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Magnetic field effects on pineal gland melatonin synthesis: comparative studies on albino and pigmented rodents
Abstract
Previous investigations have shown that the inhibitory effects of an earth-strength magnetic field on albino rat pineal melatonin synthesis is dependent on optic input. The possibility that ocular pigmentation might play a role in mammalian magnetosensitivity was explored in the present study by comparing hooded rat and golden hamsters with albino rats. Pineal melatonin synthesis, i.e. N-acetyl-transferase activity and melatonin content, was utilized as a parameter for assessing magnetosensitivity. In both rat strains nocturnal pineal melatonin synthesis was markedly inhibited following a single 30-min magnetic field stimulus consisting of a 50 degree rotation of the earth's field horizontal component. However, golden hamsters did not respond to the same magnetic stimulus, indicating a species-specific magnetosensitivity that is apparently independent of ocular pigmentation. Possible reasons for these differences are discussed.
... That pigmentation may play a crucial role in retinal MF detection was suggested by the finding that pigmented golden hamsters did not respond to MF stimulation whereas unpigmented Sprague-Dawley (SD) and hypopigmented (Long-Evans) rats showed an MF-induced inhibition of pineal melatonin synthesis (15). ...
... The ability of an artifical earth-strength MF to inhibit pineal melatonin synthesis in albino rodents (15,16,22,32) is confirmed by the present findings. We extend these results by showing that the magnetosensitivity is independent of the animal's sex. ...
... Therefore, wavelength and quantity of photons inducing a photoreceptor activation--which appears to be required for MF effects (22)--may be important, rather than the amount of light impinging on the animal's eye. An MF response was observed in hooded rats despite their retinal pigmentation (15). However, in hooded rats retinal pigmentation may be different from that in totally pigmented animals, as the fur of hooded rats is hypopigmented. ...
The ambient geomagnetic field influences a variety of biological phenomena. Electrical and biochemical parameters of the rodent pineal gland are influenced by the alteration of weak magnetic fields (MF), the magnetic receptor probably residing in the retina. However, open questions concern the role of retinal pigmentation as well as species- and sex-specific differences in MF perception. We therefore exposed male and female naturally pigmented and albino Mongolian gerbils, as well as Sprague-Dawley (SD) rats to a 60 degrees rotation of the horizontal component of the ambient MF. Alteration of nocturnal pineal melatonin content and N-acetyltransferase (NAT) activity were utilized as a parameter for assessing magneto-sensitivity. In pigmented gerbils, MF exposure resulted in no significant changes in pineal melatonin synthesis. In contrast, albino gerbils and SD rats exhibited--regardless of sex--significant decreases in pineal NAT activity and melatonin content following MF exposure. These results suggest that in rodents hypopigmentation appears to favor magnetoperception. The available evidence indicates that the pigmentation of the retina could play a crucial role.
... Kato et al. (23) reported that exposure of albino (Wistar-King) rats for 6 weeks to 50 Hz MF at 1 µT suppressed melatonin concentrations, both during the day and night, in both the plasma and pineal gland. Olcese and Reuss (24) investigated effects of combined 60 Hz vertical electric field and 60 Hz horizontal MF exposure for 6 weeks on non-human primates and found no signs of a reduction in serum melatonin concentrations in a series of three experiments. However, in another small experiment using a different exposure paradigm, they reported nearly complete suppression of the normal nocturnal rise in serum melatonin concentrations, indicating that different animal species respond differentially to different parameters of time-varying magnetic fields (25). ...
... Kato et al. (23) reported that melatonin concentration in plasma as well as in the pineal gland in rats was suppressed after exposure to a circularly polarized 50 Hz magnetic field at 1, 5, 50 or 250 µT for 6 weeks. Olcese and Reuss (24) showed that 30 min magnetic field exposure inhibited the Nacetyltransferase (NAT) activity and the melatonin content of the pineal gland in both albino Sprage-Dawley and pigmented Long-Evans (black-hooded) rat strains. Since melatonin has been shown to suppress chemically induced mammary tumorigenesis in the rat (55,56), a decrease in pineal melatonin production by MF has been implicated in the carcinogenesis of mammary tumors (22). ...
Magnetic fields (MF) of 60 Hz at 1.2 µT were previously shown to inhibit the antiproliferative effect of melatonin on MCF-7 cells (Liburdy,R.P., 1993, J. Pimeal Res. 14, 89‐ 97). In addition, three laboratories (Blackman,C.F. and Benane,S.G., 1998; Luben,R.A. and Morgan,A.P., 1998; Morris,J.E., Chrisler,W.B., Miller,D.L., Sasser,L.B. and Anderson,L.E., 1998; 20th Annual Meeting of the Bioelectromagnetics Society, At. Pete Beach, FL) independently reported results consistent with this finding. In this study, we investigated the molecular basis of the biological effects of MF using MCF-7 cells. Only 1a melatonin receptors were identified by the [ 125 I]melatonin binding assay and RT‐PCR analysis. Moreover, preceding exposures to MF of 100 µT for 3, 5 and 7 days blocked the melatonininduced inhibition of cAMP accumulation in a time-dependent manner, while none of the melatonin receptor functions or GTPase and adenylyl cyclase activities were affected. Estrogen-evoked cell proliferation was not altered by MF either. Exposure to 1.2 µT MF exerted the same effects on the melatonin-signaling pathway as that to 100 µT. Thus, this is the first study to provide evidence that MF may cause uncoupling of signal transduction from melatonin receptors to adenylyl cyclase.
... It was concluded that the experiments provided significant proof that electromagnetic fields in the extremely low frequency (elf)-range influence human circadian rhythms, and therefore, human beings. Similar results have been obtained with other organisms, revealing the influence of shielding the geomagnetic field (or applied fields in the geomagnetic range) on a variety of rodents [10][11][12][13][14][15][16][17][18] , Musca flies 3 , Drosophila 4 , and birds 7 . There is a notable paucity of negative results, although some studies revealed no effect in specific rodent strains 13,14,18 , inconsistent results 19 , or no association with circadian responses in humans (with the authors discussing the shortcomings of the study replicating changes in the GMF) 20 . ...
... Similar results have been obtained with other organisms, revealing the influence of shielding the geomagnetic field (or applied fields in the geomagnetic range) on a variety of rodents [10][11][12][13][14][15][16][17][18] , Musca flies 3 , Drosophila 4 , and birds 7 . There is a notable paucity of negative results, although some studies revealed no effect in specific rodent strains 13,14,18 , inconsistent results 19 , or no association with circadian responses in humans (with the authors discussing the shortcomings of the study replicating changes in the GMF) 20 . A novel application of the "candidate gene approach" for these GMF/circadian interactions would yield a rather specific list of candidate properties: a gene that was a molecular magnetosensor. ...
For nearly fifty years, multiple experiments have repeatedly established the influence of the geomagnetic field (GMF) on the circadian system of vari- ous organisms, including humans. Recent work on the cryptochrome genes, core components of the circadian system, fun- damentally involved with orchestrating bi- ological adaptions to the day/night cycle, have also identified the gene product as a putative magnetoreceptor. Cryptochrome thus represents the idealised "candidate gene" for GMF-circadian interactions. Indeed, it has recently been demonstrated that this gene is responsible for the mag- netosensitivity of the circadian system in Drosophila. Such investigations of circadi- an-GMF interactions have been primarily evaluated under the hypothesis that the GMF may be acting as a "secondary zeit- geber" (beyond the primary "time-giver" of the day/night cycle) for circadian systems. However, this paper demonstrates that there are clear logical and experimental objections to such a hypothesis. Most no- tably, no animal has ever been success- fully entrained to the GMF in the absence of other stimuli, despite such experiments representing the most common control in circadian biology. Thus, it is argued that a new explanatory framework is required, the foundations of which are outlined in a second paper—"The Compass within the Clock - Part 2: Does cryptochrome radical- pair based signalling contribute to temper- ature-robustness of circadian systems?"
... On the other hand physiologically-patterned, weak magnetic fields with much less absolute energy can also affect biological systems. Interaction and synergism between light and weak biofrequency-relevant magnetic fields were shown decades ago by Olcese and Reuss (1986) for rats during a discriminatory task. The presence of a weak (1 lux) red light enhanced the animals' capacities to discern the presence or absence of an extremely low frequency magnetic field. ...
Synergisms between a physiologically patterned magnetic field that is known to enhance planarian growth and suppress proliferation of malignant cells in culture and three light emitting diode (LED) generated visible wavelengths (blue, green, red) upon planarian regeneration and melanoma cell numbers were discerned. Five days of hourly exposures to either a physiologically patterned (2.5-5.0 μT) magnetic field, one of three wavelengths (3 kLux) or both treatments simultaneously indicated that red light (680 nm), blue light (470 nm) or the magnetic field significantly facilitated regeneration of planarian compared to sham field exposed planarian. Presentation of both light and magnetic field conditions enhanced the effect. Whereas the blue and red light diminished the growth of malignant (melanoma) cells, the effect was not as large as that produced by the magnetic field. Only the paired presentation of the blue light and magnetic field enhanced the suppression. On the other hand, the changes following green light (540 nm) exposure did not differ from the control condition and green light presented with the magnetic field eliminated its effects for both the planarian and melanoma cells. These results indicate specific colors affect positive adaptation that is similar to weak, physiologically patterned frequency modulated (8-24 Hz) magnetic fields and that the two forms of energy can synergistically summate or cancel.
... Effects of temperature (in mammals and reptiles), artificial magnetic field (in homeotherms), water salinity (in fish), nutritional factors, olfactory stimuli and various stress conditions (in mammals) have been investigated (cf. Vollrath 1981;Semm 1983;Vivien-Roels 1983;Vivien-Roels and P{:vet 1983;Cremer-Bartels et al. 1984;Underwood 1985;Reuss and Olcese 1986;Olcese and Reuss 1986). These experimental manipulations affect (a) ultrastructure, (b) enzymatic activities (e.g., NAT and HIOMT), (c) intracellular concentrations of some mol-Evolution and Environmental Control of Secretory Processes 115 ecules (RNA and proteins), (d) daily rhythms in the content of serotonin and melatonin and (e) spontaneous electrical activity of pineal cells. ...
The pineal organ (pineal gland or epiphysis) of vertebrates displays an unusual anatomical diversity (Oksche 1965) as well as an unusual evolution of its cell types, particularly the pineal transducers (Collin 1971; Oksche 1971; Collin and Oksche 1981). In spite of their morphological heterogeneity, pineal organs of different vertebrate species share a common function: they are components of the circadian system and, as such, effect major physiological and behavioral adjustments to daily as well as seasonal fluctuations in the environment (Collin et al. 1986a).
... Researchers have suggested several mechanisms for a possible oncostatic action of melatonin (36) such as scavenging radicals (37) enhancing immunology (38), stimulating gap-junction intercellular communication (39,40), and/or downregulating circulating levels of neuroendocrine reproductive axis hormones (41). Experimental data with rodents of 50/60-Hz magnetic field exposure and melatonin secretion are inconclusive (42)(43)(44)(45). One recent study reported that melatonin inhibited proliferation of a human endometrial cancer cell line (Ishikawa cells) in vitro (46). ...
Endometrial cancer is associated with endogenous and exogenous estrogen excess. Some investigators have posited that electromagnetic fields may influence cancer risk through estrogenic hormonal mechanisms; however, there have been no studies reporting on electric blanket exposure in relation to endometrial cancer. The authors examined this possible association between endometrial cancer risk and electric blanket or mattress cover use as part of a population-based, case-control study. This analysis included incident endometrial cancer cases 40-79 years of age, interviewed during 1994 (n = 148; response rate, 87%) and identified from the Wisconsin tumor registry. Female controls of similar age were randomly selected from population lists (n = 659; response rate, 85%). Information regarding electric blanket and mattress cover use and endometrial cancer risk factors was obtained through structured telephone interviews approximately 1 year after diagnosis. After adjustment for age, body mass index, and postmenopausal hormone use, the risk of endometrial cancer was similar among ever users (odds ratio = 1.04, 95% confidence interval: 0.70, 1.55) and among current users (odds ratio = 0.87, 95% confidence interval: 0.49, 1.54) as compared with never users. Despite its small size and potential misclassification of exposure, this study provides evidence against an association between electric blanket or mattress cover use and endometrial cancer.
... Various studies have indicated that magnetic field (MF) exposures suppress nighttime pineal melatonin content or blunt the nocturnal rise in circulation [11]. Although MF exposure effects have been found in some [12][13][14][15] but not all studies [13,16,17], comparisons are complicated by the use of different exposure paradigms, infrequent blood collection protocols, and the number of different rodent species used. Recent experiments in the adult Djungarian hamster also indicate that acute exposure to a 60-Hz MF (1 gauss for 15 min beginning 2 h before dark) delays or blunts the nighttime melatonin rhythm in long days [18,19]. ...
Photoperiodic regulation of the melatonin rhythm was studied in juvenile Djungarian hamsters to test the hypothesis that magnetic field (MF) exposures disrupt sexual maturation. Juveniles in long or short days postweaning were exposed each day to a 1-gauss 60-Hz MF (15 min, 2 h before lights-off). At age 25 days, nighttime duration of the melatonin rise in the pineal gland and circulation of sham-treated controls (adjacent coil system but without current) was < 8 h in long-day juveniles and nearly 13 h in short-day hamsters. This is the first study in juveniles to demonstrate that the melatonin rhythm duration is regulated by photoperiod and that reproductive development was not disrupted by daily or acute MF exposures; puberty was initiated in long days but arrested by short days, irrespective of MF treatment. In a replicate study, MF exposures had no effect on the duration of increased melatonin. In the initial and the replicate study, amplitude differences in the nighttime pineal or serum melatonin rise possibly reflected inherent variability in repetitive melatonin rhythms. In addition, effects of daily melatonin injections to arrest puberty were not blocked by daily MF exposures. The findings support the conclusion that MF exposures fail to disrupt photoperiodic time measurement or the neuroendocrine mechanism regulating reproductive maturation in the juvenile Djungarian hamster.
... The previously proposed melatonin hypothesis of GMS [15,16,18,31,38,39,41,42] is predicated on observations that GMA or applied magnetic fields in the geomagnetic range have been associated with lower mean nocturnal melatonin secretion (or its major metabolite 6-hydroxymelatonin-sulfate: 6-OHMS) in studies of both healthy individuals and CV patients [15,16,41,47,48]. Such findings have been confirmed in animal experimental studies [49 -54], although some negative results have been obtained [52,54] (see electronic supplementary material, table). Moreover, melatonin plays a central role in the regulation of diverse biological functions, and the other observed relationships of GMA (e.g. ...
A controversial body of literature demonstrates associations of geomagnetic storms (GMS) with numerous cardiovascular, psychiatric and behavioural outcomes. Various melatonin hypotheses of GMS have suggested that temporal variation in the geomagnetic field (GMF) may be acting as an additional zeitgeber (a temporal synchronizer) for circadian rhythms, with GMS somehow interfering with the hypothesized system. The cryptochrome genes are known primarily as key components of the circadian pacemaker, ultimately involved in controlling the expression of the hormone melatonin. Cryptochrome is identified as a clear candidate for mediating the effect of GMS on humans, demonstrating the prior existence of several crucial pieces of evidence. A distinct scientific literature demonstrates the widespread use of geomagnetic information for navigation across a range of taxa. One mechanism of magnetoreception is thought to involve a light-dependent retinal molecular system mediated by cryptochrome, acting in a distinct functionality to its established role as a circadian oscillator. There is evidence suggesting that such a magnetosense--or at least the vestiges of it--may exist in humans. This paper argues that cryptochrome is not acting as secondary geomagnetic zeitgeber to influence melatonin synthesis. Instead, it is hypothesized that the cryptochrome compass system is mediating stress responses more broadly across the hypothalamic-pituitary-adrenal (HPA) axis (including alterations to circadian behaviour) in response to changes in the GMF. Two conceptual models are outlined for the existence of such responses--the first as a generalized migrational/dispersal strategy, the second as a stress response to unexpected signals to the magnetosense. It is therefore proposed that GMS lead to disorientation of hormonal systems in animals and humans, thus explaining the effects of GMS on human health and behaviour.
... In experimental animals, external magnetic fields, when applied at night, acutely suppress the activity of the melatonin synthesizing enzymes serotonin N-acetyltransferase (SNAT) and hydroxyindole-0-methyl transferase (HIOMT), reduces the pineal content of cyclic adenosine monophosphate (CAMP) (Rudolph et al., 1988) as well as nocturnal melatonin secretion (Cremer-Bartels et al., 1983;Welker et al., 1983;Olcese & Reuss, 1986). Consequently, since melatonin inhibits dopamine functions (and thus may be acting as an endogenous neuroleptic-type hormone), external application of magnetic fields would be expected to increase dopaminergic activity in the striatal/mesolimbic areas and to ameliorate the bradykinesia, rigidity, and resting tremor of PD. ...
It was found that moderate electromagnetic shielding, which attenuates constant and variable components of the geomagnetic field (19 h per day for 10 days), induces in male rats the development of depression-like behavior. This behavior is diagnosed on the basis of increased passive swimming time and a decreased duration of active swimming in the Porsolt test. These behaviors reach their peak on days 3–4 of the experiment. The daily administration of 1 mg/kg exogenous melatonin reduces these depression-like behaviors as soon as day 1 of the experiment, and this effect persists throughout all stages of the experiment. Electromagnetic shielding and the administration of 1 mg/kg exogenous melatonin do not change the levels of intraspecies aggressiveness. An increase in melatonin dosage to 5 mg/kg even further reduces depression-like symptoms and stops the increase in intraspecies aggressiveness during the experiment. The conclusion is made that melatonin plays an important role in the mechanisms of physiological effects of a weakened electromagnetic geomagnetic field.
To maintain homeostasis, mammals possess precise coordinating control systems that react to changes in the internal and external environments. Among these controllers are the interacting neural and endocrine systems, which are among the prime physiological regulators of the body. Perturbations caused by environmental factors such as electric, magnetic, or electromagnetic fields can be manifested by functional changes in these regulatory systems of the body. Acting alone or in concert, the various components of the neuroendocrine system play a central role in the integrative activities that are required for homeostasis.
Wilson et al. (1981, 1983, 1986) demonstrated that exposure of rats to electric fields for 3 weeks both reduces, by about 50%, the amplitude of the nocturnal peak in melatonin production by the pineal gland and delays, by about 2 hours, the time of peak melatonin production. Semm (1983), Welker et al. (1983), and Olcese and Reuss (1986) have demonstrated magnetic field effects on pineal melatonin synthesis in rodents.
The consequences of electromagnetic exposure for human health are receiving increasing scientific attention and have become the subject of a vigorous public debate. In the present study we evaluated the effects of magnetic field on pineal function in man and rat.
Two groups of Wistar male rats were exposed to 50-Hz magnetic fields of either 1,10 or 100 μT. The first group was exposed for 12 h and the second for 30 days (18 h per day). Short-term exposure depressed both pineal NAT activity and nocturnal serum melatonin concentration, but only with the highest intensity used (100 μT). Long-term exposure to a magnetic field of 10 and 100 μT significantly depressed the nighttime peak of serum melatonin concentration and pineal NAT activity. Our results show that sinusoidal magnetic field altered the production of melatonin through inhibition of pineal NAT activity. Both the duration and the intensity of exposure played an important role in this effect.
In the second step of this study, 32 young men (20–30 years old) were divided into two groups (control group, i.e., sham-exposed: 16 subjects; exposed group: 16 subjects). The subjects were exposed to the magnetic field from 2300 h to 0800 h (i.e., for 9 h) while lying down. In one experiment the exposure was continuous; in the second one, the magnetic field was intermittent. No significant differences were observed between sham-exposed (control) and exposed men for serum melatonin, 6-sulfatoxymelatonin, immunological and hematological variables, and serum cortisol.
This study suggests that, at least under the conditions used in our experiment, acute exposure to either a continuous or an intermittent 50-Hz magnetic field of 10 μT does not affect plasma melatonin concentration or its circadian rhythm in healthy young men.
The preliminaries of this conference have revealed that there is a fair amount of scepticism among scientists regarding possible interrelationships between the pineal gland hormone melatonin and cancer. I am sure that by the end of this conference we will be in a better position to judge for ourselves whether or not the scepticism is justified. In my view, despite the scepticism, scientists have a moral obligation towards the public, and especially the hundreds of thousands of cancer patients, to explore even the remotest possibilities to prevent, cure, or at least alleviate the suffering of this disease. On the other hand, it is mandatory not to waste public money, but to discontinue a specific branch of research once we are convinced that it is no longer promising.
For centuries the idea that animals respond to ambient magnetic fields (MF) has been restricted largely to speculations based on rare observations in the field. However, in the past few decades a slow but gradual increase in scientific interest has begun to delineate some aspects of magnetoreception in vertebrates (Adey, 1981; Gould, 1983; Kirschvink, 1989). The ultimate goal of these studies has been, and continues to be, the identification of physiological and anatomical components of a magnetoreceptor.
Organisms have evolved in the presence of a variety of magnetic and electromagnetic fields. These naturally occurring fields include the earth’s geomagnetic field, electromagnetic fields (EMFs) resulting from solar radiation, and EMFs associated with tropospheric labilities such as lightning discharges and other atmospheric changes. In the last six decades there has been an explosive growth in man-made electromagnetic fields associated with the expanding electric power distribution systems and communication networks. In addition, many people are now exposed to various types of magnetic and electromagnetic fields in both the workplace and at home.
Magnetic fields (MF) can influence biological systems in a wide range of animal species and humans. We report here on the influence of static MF, locally applied to the brain area, on immune system performances in the rat. In the first series of experiments two AKMA micromagnets (M) with the influx density of 600 Gauss were bilaterally implanted (with “N” polarity facing the cranial bones) and fixed to the skull posterior to the fronto-parietal suture (parietal brain exposure). Rats implanted with iron beads (I) and sham-operated (SO) rats served as controls. Animals were exposed to MF or I during different periods of time before and after immunization with several soluble or cellular antigens. We report here on the in vivo immunoregulating effects of centrally applied MF on plaque-forming cell (PFC) response, local hypersensitivity skin reactions and experimental allergic encephalomyelitis. The selective influence of MF applied to different brain regions on PFC response was evaluated, as well. For this purpose, two M were bilaterally implanted in the area of (a) frontal, (b) parietal and (c) occipital brain regions. Rats were under the influence of MF for 20 days before and 4 days after immunization with sheep red blood cells. Groups of nonimmunized rats were exposed for 14, 24 and 34 days to parietally implanted M or I, and the number of peripheral blood CD4+ and CD8+ cells determined by mouse anti-rat W3/25 and MRC OX 8 monoclonal antibodies.
The results show an overall in vivo immunopotentiation of humoral and cell-mediated immune responses in rats exposed to MF. Furthermore, these immunomodulating effects of centrally applied MF depend on at least two basic parameters, time of exposure and brain region exposed. The highest immune performance was obtained after exposure of the occipital brain region for a total period of 24 days. The results provide further evidence of the complex interrelationship between the environment, the central nervous system and the immune system.
This paper addresses the model predictive control (MPC) problem of a hybrid system that consists of a continuous-time linear system and a directed graph, called here directed-graph type hybrid systems (DGHS). One of the keys to such a problem is to represent a directed graph in an effective form in order to reduce the original problem into the mixed integer problem. This paper gives a solution to this issue by representing it with a time-varying linear system model with a relatively small number of binary input (free) variables. Furthermore, an online method for updating a model of a time-varying directed graph is proposed. Finally, it is shown by numerical examples that the proposed method is effective.
Data were obtained from the literature on the annual pattern of manic‐depressive attacks and on the time of admission to psychiatric hospitals. These data were correlated with the contemporaneous geomagnetic activity, using the Spearman rank correlation coefficient. The magnetic indices Ap, aa and Na were used, indices which are sensitive to solar corpuscular radiation. Manic‐depressive attacks and geomagnetic disturbances exhibited prominent seminannual patterns, with the correlations positive and statistically significant in half the tests. No significant outcomes were obtained with the admission data. The literature on geomagnetic effects on melatonin and on a melatonin dysfunction in depression is briefly reviewed, and a possible geomagnetic factor in depression is hypothesized.
Environmental risk factors affect human biological system to different extent from modification of biochemical reaction to cellular catastrophe. There are considerable public concerns about electromagnetic fields and endocrine disruptors. Their risk assessments have not been fully achieved because of their scientific uncertainty: electromagnetic fields just modify the bioreaction in the restricted cells and endocrine disruptors are quite unique in that their expression is dependent on the exposure periods throughout a life. Thus, we here describe their molecular characterization to establish the new risk assessments for environmental physicochemicals.
The annual pattern of human conceptions in the United States of America for the eleven year interval from Jan., 1967 thru Dec, 1976 were analyzed with a regression technique. Initially an orbital model, consisting of two sine curves, one with an period of one year that peaked in June and the other with a semiannual period that peaked in March and September, was fitted to the monthly values of conceptions for the 132 months of the 11 year interval. Separate analyses were conducted for each state. An analysis of variance indicated that the orbital model was a significant predictor for all states except Montana and North Dakota. Inspection of the residuals revealed systematic trends that were accounted for by adding other predictor variables. A latitudinal trend in the percentage of the variance accounted for by the orbital model was established, as well as a latitudinal trend in the residuals that indicated systematic changes with latitude in April and July values. The annual pattern of “mood swings”; in patients with seasonal affective disorders was found to enter the regression equation at higher latitudes. The previously established latitudinal trend in seasonal affective disorder and in multiple sclerosis were discussed and compared to the latitudinal trend in conceptions.
This study investigated the effects of MRI on receptor-mediated activation of pineal gland indole biosynthesis. Exposure of rats to MRI reduced the effects of isoproterenol on pineal serotonin andN-acetylserotonin levels suggesting that strong magnetic fields and/or radio-frequency pulsing used in MRI inhibited beta-adrenergic activation of the gland. There was no effect of MRI on saline controls.
In addition to the well-documented seasonal cycles of mating and birth, there are also significant seasonal cycles of illness and death among many animal populations. Challenging winter conditions (i.e., low ambient temperature and decreased food availability) can directly induce death via hypothermia, starvation, or shock. Coping with these challenges can also indirectly increase morbidity and mortality by increasing glucocorticoid secretion, which can compromise immune function. Many environmental challenges are recurrent and thus predictable; animals could enhance survival, and presumably increase fitness, if they could anticipate immunologically challenging conditions in order to cope with these seasonal threats to health. The annual cycle of changing photoperiod provides an accurate indicator of time of year and thus allows immunological adjustments prior to the deterioration of conditions. Pineal melatonin codes day length information. Short day lengths enhance several aspects of immune function in laboratory studies, and melatonin appears to mediate many of the enhanced immunological effects of photoperiod. Generally, field studies report compromised immune function during the short days of autumn and winter. The conflict between laboratory and field data is addressed with a multifactor approach. The evidence for seasonal fluctuations in lymphatic tissue size and structure, as well as immune function and disease processes, is reviewed. The role of pineal melatonin and the hormones regulated by melatonin is discussed from an evolutionary and adaptive functional perspective. Finally, the clinical significance of seasonal fluctuations in immune function is presented. Taken together, it appears that seasonal fluctuations in immune parameters, mediated by melatonin, could have profound effects on the etiology and progression of diseases in humans and nonhuman animals. An adaptive functional perspective is critical to gain insights into the interaction among melatonin, immune function, and disease processes.
Magnetoencephalographic (MEG) recordings of parkinson's disease (PD) patients were obtained using of a whole-head 122-channel magnetometer SQUID and analyzed with linear signal Fourier statistical analysis. External transcranial magnetic stimulation in the order of pico Tesla (pTMS) was applied on the above patients with proper field characteristics (Intensity: 1-7.5pT, frequency: the α – rhythm of the patient: 8-13Hz) with the ones obtained prior to pTMS. The MEG recordings after the application of pTMS were shown a rapid attenuation of the abnormal brain activity followed by an increase of the low frequency components toward the patients' α – rhythm. In addition were seen improvement and normalization of their EEGs and MEGs.
The sections in this article are:
Environmental protection of Antarctica is a fundamental principle of the Antarctic Treaty. Impact assessment and significance evaluation are due for every human activity on the remote continent. While chemical and biological contaminations are widely studied, very little is known about the electromagnetic pollution levels. In this frame, we have evaluated the significance of the impact of Mario Zucchelli Antarctic Station (Northern Victoria Land) on the local geomagnetic field. We have flown a high resolution aeromagnetic survey in drape mode at 320m over the Station, covering an area of 2km(2). The regional and the local field have been separated by a third order polynomial fitting. After the identification of the anthropic magnetic anomaly due to the Station, we have estimated the magnetic field at the ground level by downward continuation with an original inversion scheme regularized by a minimum gradient support functional to avoid high frequency noise effects. The resulting anthropic static magnetic field at ground extends up to 650m far from the Station and reaches a maximum peak to peak value of about 2800nT. This anthropic magnetic anomaly may interact with biological systems, raising the necessity to evaluate the significance of the static magnetic impact of human installations in order to protect the electromagnetic environment and the biota of Antarctica.
Breast cancer incidence rates have increased substantially over the past several decades in most Westernized countries, with
great variation in incidence rates between countries (Kamangar et al. 2006). Given such patterns of breast cancer incidence
and the fact that established risk factors for breast cancer explain less than half of all incident cases (Madigan et al.
1995), it has been widely suggested that the environment may play an important role in breast cancer etiology. Several classes
of environmental exposures have been investigated in relation to breast cancer risk, with sources of exposure as diverse as
the proposed mechanisms linking exposure to breast cancer risk.
There has been increasing concern over possible human health risks associated with exposure to alternating current (AC) magnetic
fields induced by transmission and distribution systems. To accurately assess the possible health risk, it is necessary to
conduct a wide range of studies with appropriate exposure systems both for animal and human subjects. Because AC transmission
lines are three phase, the magnetic field at ground level tends to be elliptically polarized (Deno, 1976) and is represented
fairly well by a rotating vector. In the laboratory, this rotating vector can be simulated by the sum of horizontal and vertical
magnetic fields 90° out of phase. It is very important to allow the simultaneous exposure of as many animals as possible.
An exposure facility must be designed to fill these requirements.
Presumably unrelated behaviors (e.g. psychiatric admissions, seizures, heart failures) have been correlated with increased
global geomagnetic activity. We have suggested that all of these behaviors share a common source of variance. They are evoked
by transient, dopamine-mediated paroxysmal electrical patterns that are generated within the amygdala and the hippocampus
of the temporal lobes. Both the probability and the propagation of these discharges to distal brain regions are facilitated
when nocturnal melatonin levels are suppressed by increased geomagnetic activity. In support of this hypothesis, the present
study demonstrated a significant correlation of Pearsonr=0.60 between mortality during the critical 4-day period that followed induction of libic seizures in rats and the ambient
geomagnetic activity during the 3 to 4 days that preceded death; the risk increased when the 24 h geomagnetic indices exceeded
20 nT for more than 1 to 2 days.
Although the behavioral changes observed generally are subtle, the above mentioned studies on rodents, baboons, and humans, do indicate that some cognitive functions are influenced acutely by ELF magnetic field exposure.
Ziel der vorliegenden Arbeit war es, die vorhandenen experimentellen und epidemiologischen Studien zum Zusammenhang zwischen der Exposition gegenüber elektromagnetischen Feldern und dem Krebsrisiko zusammenzustellen und zu bewerten. Dafür wurden mittels Medline – Recherche 165 Originalarbeiten und Übersichtsarbeiten analysiert. Die experimentellen Studien können die Frage, wie Krebs durch elektromagnetische Felder entstehen könnte, nicht beantworten. Es gibt allerdings vielversprechende Ansätze mit nachvollziehbaren Hypothesen, die in Zukunft eine Erklärung liefern könnten, wie z. B. die Melatoninhypothese oder den Ansatz, elektromagnetische Felder als Promotoren oder Copromotoren zu untersuchen. Die epidemiologischen Studien belegen keinen Zusammenhang zwischen nicht-beruflicher Exposition mit elektromagnetischen Feldern extrem niedriger Frequenz und Krebsrisiko, weder bei Kindern noch bei Erwachsenen. Im beruflichen Bereich dagegen gibt es Hinweise auf eine Korrelation langandauernder, gleichbleibender Belastung mit starken Feldern und einem erhöhten Leukämie- und Gehirntumorrisiko. Zukünftige Studien auf diesem Gebiet müssen diverse relevante mögliche Confounder berücksichtigen, die Exposition jedes Probanden am Arbeitsplatz und zu Hause muß gemessen werden, adäquate Poweranalysen zur Ermittlung der benötigten Fallzahlen sind unerläßlich. Zu den Auswirkungen hochfrequenter Felder gibt es nur wenige Studien. Die vorliegenden Ergebnisse geben keine Hinweise auf ein erhöhtes Krebsrisiko.
To test the hypothesis that the wavelength (color) of ambient lightning should modulate experiences of a sensed presence when the right hemisphere was stimulated by weak, burst-firing magnetic fields, volunteers were exposed for 30 min to this condition or to a sham field while they sat (eyes opened) in either dim red, green, or white light. Subjects exposed to the magnetic field reported significantly more visual sensations along the left side in red light and along the right side in green light. The significant interaction between ambient color and the field treatment was due to the marked increase in experiences of dizziness, sensed presence, "ego-alien" thoughts, and detachment from the body and "being somewhere else" for subjects exposed to the magnetic field while sitting in red light. The concurrence of entoptic images experienced within the upper left peripheral visual field and the sensed presence supported the hypothesis that both are associated with the intrusion of right hemispheric processes into left hemispheric awareness.
Application of external weak magnetic fields recently has been reported to be efficacious in the treatment of a 62-year-old patient with idiopathic Parkinson's disease (PD) complicated by levodopa-induced fluctuations in motor response ("on-off"). I report an additional case of a 67-year-old man with idiopathic PD and levodopa-related motor fluctuations who likewise experienced marked and sustained improvement in Parkinsonian symptoms and amelioration of "on-off" symptoms following the application of external weak magnetic fields. Based on these observations it is concluded that artificial weak magnetic fields may be beneficial for the treatment of PD complicated by levodopa-related "on-off" phenomenon. Furthermore, since in experimental animals external magnetic fields alter the secretion of melatonin, which in turn has been shown to regulate striatal and mesolimbic dopamine-mediated behaviors, it is proposed that the antiParkinsonian effects of weak magnetic fields are mediated via the pineal gland.
We have recently reported that application of external, weak magnetic fields attenuated seizures in epileptic patients (Anninos et al., 1991). However, the mechanisms by which magnetic stimulation reduces seizure activity are unknown. We present four non-selected epileptic patients the first to be rated by the senior author, in whom treatment with magnetic fields attenuated the severity of seizures and also altered the circadian occurrence of seizures. The first patient, a 27-year old woman, had generalized tonic-clonic seizures which occurred almost exclusively at night. Following treatment with magnetic fields she experienced attenuation of seizures which then occurred only after waking up in the morning. The second patient, a 42-year old man, had generalized tonic-clonic seizures which occurred randomly during the day and night. Treatment with magnetic fields resulted in disappearance of nocturnal seizures with seizures now occurring exclusively during the day. The third patient, a 21-year old woman had generalized tonic-clonic seizures which occurred randomly during the day. After treatment with magnetic fields she was free of seizures for 7 months, but recently experienced one attack in the morning hours while sleeping. The fourth patient, a 39-year old woman had secondary generalized seizures since the age of 12. Prior to treatment with magnetic fields she had 8-10 seizures daily which occurred randomly during the day and night hours. Magnetic treatment resulted in attenuation in seizure frequency (1-2/day) with seizures now occurring only during the day. We propose, therefore, that since the pineal gland is a magnetosensitive organ which "transduces" environmental information of the light-dark cycle and of the earth's magnetic field into an endocrine message mediated via the circadian release of melatonin, and since it is recognized that melatonin attenuates seizure activity, artificial magnetic fields attenuate seizure activity by altering the functions of the pineal gland.
Levodopa-induced dyskinesias are a common complication of chronic dopaminergic therapy in patients with Parkinson's disease (PD). The overall prevalence of levodopa-induced dyskinesias ranges from 40%-90% and is related to the underlying disease process, pharmacologic factors, and to the duration of high dose levodopa therapy. The mechanisms underlying the emergence of levodopa-induced dyskinesias are unknown, although most investigators favor the theory that striatal dopamine receptor supersensitivity is directly responsible for the development of these abnormal movements. In laboratory animals, the pineal hormone melatonin has been shown to regulate striatal dopaminergic activity and block levodopa-induced dyskinesias (Cotzias et al., 1971). Since the pineal gland is known to be a magnetosensitive organ and as application of external magnetic fields has been shown to alter melatonin secretion, we studied the effects of application of external artificial weak magnetic fields in a Parkinsonian patient with severe levodopa-induced dyskinesias ("on-off"). Application of weak magnetic fields with a frequency of 2 Hz and intensity of 7.5 picotesla (pT) for a 6 minute period resulted in a rapid and dramatic attenuation of Parkinsonian disability and an almost complete resolution of the dyskinesias. This effect persisted for about 72 hours after which the patient regressed to his pretreatment state. To ascertain if the responses elicited in the laboratory were reproducible, the patient was instructed to apply magnetic fields of the same characteristics daily at home. These subsequent treatments paralleled the initial response with a sustained improvement being maintained during an observation period lasting at least one month. This case demonstrates the efficacy of weak magnetic fields in the treatment of Parkinsonism and motor complications of chronic levodopa therapy.
The discovery of rapid eye movement (REM) sleep by Aserinsky and Kleitman in 1953 initiated the impetus for sleep research and specifically the investigations of the effects of REM sleep deprivation (RSD) on animal and human behavior. The behavioral effects of RSD include the enhancement of motivational and "drive"-related behaviors. In laboratory animals, RSD has been reported to increase appetite, sexual behavior, aggressiveness, and locomotor activity. Moreover, RSD reportedly improves mood in patients with endogenous depression and heightens appetite and sexual interest in normal subjects. Since "drive"-related behaviors are thought to involve activation of limbic dopaminergic reward sites, RSD may enhance motivational behaviors through an action on limbic dopaminergic functions. In the present communication, we present two patients (one with multiple sclerosis and the other with Parkinson's disease) in whom treatment with magnetic fields produced behavioral effects which paralleled those observed in REM-sleep-deprived animals and humans. We propose, therefore, that the behavioral and mental effects of treatment with magnetic fields may be mediated via RSD and, by inference, involve activation of limbic dopaminergic reward sites.
Seasonal affective disorder is characterized by recurrent winter depression associated with hypersomnia, overeating, and carbohydrate craving. The severe form of winter depression affects about 5% of the general population and is believed to be caused by light deficiency. About 70%-80% of patients with winter depression experience attenuation of symptoms when exposed to bright light therapy. Hypotheses pertaining to the pathogenesis of winter depression implicate the effects of light on different characteristics of circadian rhythms. One of the environmental factors which may be implicated, in addition to light, in the pathophysiology of winter depression is the geomagnetic field. There is strong indication that the pineal gland is a magnetosensitive system and that changes in the ambient magnetic field alter melatonin secretion and synchronize the circadian rhythms. In man, shielding of the ambient magnetic field significantly desynchronizes circadian rhythms which could be gradually resynchronized after application of magnetic fields. The strength of the environmental magnetic field diminishes during the winter months, leading to increased susceptibility for desynchronization of circadian rhythms. Thus, since the acute application of magnetic fields in experimental animals resembles that of acute exposure to light with respect to melatonin secretion (i.e., suppression of melatonin secretion), magnetic treatment might be beneficial for patients with winter depression. In addition, since the environmental light and magnetic fields, which undergo diurnal and seasonal variations, influence the activity of the pineal gland, we propose that a synergistic effect of light and magnetic therapy in patients with winter depression would be more physiological and, therefore, superior to phototherapy alone.(ABSTRACT TRUNCATED AT 250 WORDS)
The nightly production and secretion of melatonin by the pineal gland, an endocrine organ near the anatomical center of the brain, provides important time-of-day and time-of-year information to the remainder of the body. In mammals, the circadian rhythm of melatonin (low levels during the day and high levels at night) is synchronized by the prevailing light:dark environment with the retinas of the eyes doing the photoreception required for the induction of this rhythm. The advent of artificial light sources has allowed animals or humans to be exposed to light at unusual times, i.e., during the night. Light falling on the retinas at night leads to a rapid depression in the production and secretion of melatonin by the pineal gland. The magnitude of the drop in circulating melatonin due to light exposure at night is related to the brightness (intensity) as well as the wavelength (color) of light to which humans are exposed. The lowered melatonin values following unusual light exposure at night provide erroneous information to a number of organs that respond to the melatonin message since the signal implies it is day when, in fact, it is still night. Besides visible light, certain ultraviolet wavelengths as well as extremely low frequency electric and magnetic fields may also disturb the melatonin rhythm. These nonvisible wavelengths may influence the circadian melatonin rhythm by mechanisms similar to those by which light causes disturbances of melatonin production and release.
We have recently demonstrated that Magnetoencephalographic (MEG) brain measurements in patients with seizure disorders show significant MEG activity often in the absence of conventional EEG abnormalities. We localized foci of seizure activity using the mapping technique characterized by the ISO-Spectral Amplitude (ISO-SA) on the scalp distribution of specified spectral components or frequency bands of the emitted MEG Fourier power spectrum. In addition, using an electronic device, we utilized the above recorded activity to emit back the same intensity and frequency of magnetic field to the presumed epileptic foci. Using this method we were able, over the past two years, successfully to attenuate seizure activity in a cohort of over 100 patients with various forms of epilepsy. We now present in more detail three randomly selected patients with partial seizures in whom application of an external artificial magnetic field of low intensity produced a substantial attenuation of seizure frequency during an observation period extending from 10 to 14 months. All patients had previously obtained only partial response to conventional anticonvulsant therapy. Attenuation in seizure frequency was associated with normalization of the MEG activity. These cases demonstrate that artificial magnetic treatment may be a valuable adjunctive procedure in the management of partial seizures. The possible mechanisms underlying the anticonvulsant properties of magnetic stimulation at both cellular and systemic levels are discussed. Specifically, since the pineal gland has been shown to be a magnetosensitive organ which forms part of a combined compass-solar clock system, and since it exerts an inhibitory action on seizure activity in both experimental animals and humans, we discuss the potential pivotal role of the pineal gland in the long term anticonvulsant effects of external artificial magnetic stimulation.
The prominent endogenous cycle of the sun, with a period of approximately 11 years, is correlated with human conceptions. Time series methods (periodograms and periodic regression analyses) established that an approximate 11-year period exists in the data on births in the 20th century (1909-1985) in the United States and in New Zealand. Statistical comparisons indicated a reliable and direct relationship of conceptions with the approximately 11-year sunspot cycle. These findings were discussed in terms of the possible mediating role of geomagnetic disturbances and other factors that have been suggested in the literature to mediate human conception.
This study investigated the effects of MRI on receptor-mediated activation of pineal gland indole biosynthesis. Exposure of rats to MRI reduced the effects of isoproterenol on pineal serotonin and N-acetylserotonin levels suggesting that strong magnetic fields and/or radio-frequency pulsing used in MRI inhibited beta-adrenergic activation of the gland. There was no effect of MRI on saline controls.
Data obtained from the literature on the annual pattern of human conceptions and plasma melatonin at high latitudes indicated that simple annual rhythms do not exist. Instead, prominent semiannual rhythms are found, with equinoctial troughs and solsticial peaks. A prominent semiannual environmental event is the magnetic disturbance induced by the solar wind. The semiannual magnetic disturbances are worldwide, but most pronounced in the auroral zones where the corpuscular radiation enters the atmosphere. Magnetic indices that predominantly reflect these events were obtained from the literature and correlated with the melatonin and conception data. Significant and inverse correlations were found for Inuit conceptions and the melatonin data. The correlations obtained for 48 contiguous states of the United States indicated that only the extreme northern states exhibited this relationship. These data were compared with a previous correlational study in the United States which established that sunshine was correlated with conceptions in the middle latitude and southern states. An hypothesis of dual control by electromagnetic and magnetic energies is proposed: melatonin is a progonadal hormone in humans controlled by both factors, depending on their relative strength. Other studies are reviewed regarding the possible factors involved in determining the annual pattern of human conceptions. Demographic studies of geographic variation in temporal patterns of conceptions, with particular regard to variations of the magnetic fields on the earth's surface, may provide some insight into the efficacy of these different factors.
The literature on biological effects of weak electromagnetic fields of a frequency of 200 MHz or less is surveyed. The topic has been extraordinarily controversial, in part because of disputed assertions about a role for electromagnetic fields in carcinogenesis or production of abnormalities in growth and development. There is fairly widespread acceptance of certain beneficial effects, particularly the stimulation of healing. An increasing number of reports point to interactions between static magnetic fields and time-varying fields in the production of some effects. Safety implications are noted along with the hypothetical possibility of production of experimental artifacts by electromagnetic fields in MRS research.
Previously it was demonstrated that experimental alteration of the ambient magnetic field at night significantly reduced catecholamine levels in the retinae of Sprague-Dawley rats. As this effect appeared to depend on intact photoreceptors, it seemed of interest to examine whether the dopamine response to altered magnetic fields (MFs) differed between rod-dominant retinae and cone-dominant retinae. Furthermore, the effect of MFs on daytime dopamine content was explored. As in previous nocturnal investigations, dopamine levels in light-adapted (i.e. daytime) retinae from albino rats were significantly reduced by MFs. In the cone-dominant retina of the pigment ground squirrel, a similar MF effect was observed. However, in the rod-dominant retina of the golden hamster, dopamine levels increased significantly following daytime MF exposure. These results indicate that the retinal dopaminergic system is differentially responsive to MFs in various rodent species. Hence, the retina may play an important role in the perception of MFs by mammals.
Magnetosensitivity of the rat's pineal cyclic adenosine monophosphate (cAMP) system was investigated. During their dark phase, rats were exposed for one hour to a static magnetic field (MF) inverting the horizontal component of the natural MF. MF-exposed animals showed a 38% decrease in pineal cAMP content (1.21 pmol/pineal gland) compared to a non-exposed control group (1.96 pmol/pineal gland).
Mice given morphine displayed diel rhythms in the latency of their behavioral response to placement on a hot plate, there being a several fold increase in their nocturnal reaction times. Exposure to a rotating magnetic field eliminated the day-night analgesia rhythms, reducing over 5-10 days the enhanced nocturnal latencies to those found during the day. The attenuation returned to normal nocturnal levels several days after removal of the rotating magnetic field and could be subsequently re-established by reapplication of the magnetic field condition. It is suggested that these changes in analgesia may reflect alterations in the activity of the pineal gland during exposure to magnetic fields.
Sensory-neural, biochemical-metabolic, and physiological anomalies occur in albino mammals. There are ontogenic and biochemical parallels between the senses, peripheral nervous system, endocrine glands, metabolism, and melanin pigmentation. All albino mammals examined have abnormal optic systems. Many drugs cannot be adequately evaluated in an albino model because of melanin's ability to bind and interact with some chemicals. There is evidence that a general reduction in melanin pigment is correlated with a paucity of amino acids necessary for normal chemical function of the brain. There is a high probability that enzyme levels indicative of metabolic performance are deficient in the liver and kidneys oif albinos. Congenital defects are associated with hypopigmentation in animal models and human syndromes. Melanin is found in abundance in the eye, inner ear, and midbrain where neural impulses are initiated indicating a possible role as an electrophysiologic mechanism. Microwave irradiation differentially affects albino and pigmented animals. Implications of these observations and other reports of anomalies associated with hypopigmentation suggest caution in the use of albino and other hypomelanotic animals as normal models in biological research.
The electrical activity of about 30% of a homing pigeon’s pineal cells can be altered by changing the horizontal or vertical component of the natural magnetic field, using two pairs of Helmholtz coils. The cells respond to a rapid and/or gradual change in the magnetic field with either excitation or inhibition. In some of the sensitive cells the responses to magnetic field changes could not be repeated.
Previous studies have shown that earth-strength magnetic fields (MF), i.e. in the range of 10-4 Tesla (T), are capable of significantly inhibiting nocturnal pineal melatonin synthesis as measured by pineal N-acetyltransferase activity (NAT) and pineal melatonin content. As nuclear magnetic resonance (NMR) imaging has become an important diagnostic procedure, it was decided to explore the effects of NMR-strength MF on pineal melatonin synthesis in the rat. Experiments were conducted under dim red light at 02:30 h in a Brucker NMR tomograph (field strength 0.14 T). Thirty minutes of exposure failed to affect pineal NAT activities or melatonin content significantly. Possible explanations for this lack of effect of a strong MF on pineal melatonin synthesis include (1) the presence of a 'magnetic window' which 'filters out' abnormally strong MFs or (2) a magnetosensitivity which depends less on intensity changes but more on orientational changes of the MF.
Schulten K. Magnetic field effects in chemistry and biology // Festkörperprobleme / J. Treusch, ed.
Braunschweig, 1982. V. 22. P. 61–83.
Studies of the effects of environmental low frequency electromagnetic fields on isolated cellular systems and tissue preparations derived from brain, bone, blood, and pancreas are reported. Behavioral effects of 60 Hz fields were examined in monkeys. Bioeffects of low level microwave fields modulated at 60 Hz and other ELF frequencies were also examined. Findings in the present studies emphasize a key role for cell membrane surfaces in detecting ELF environmental fields. Two broad groups of exposure techniques have been utilized. In the ELF spectrum, 60 Hz environmental fields were imposed on monkeys during behavioral task performance. Field intensities from 50 to 1000 V/m were tested in different experiments. The monkeys were exposed to a horizontal electric field. In tissue and cell culture preparations, ELF electric fields were generated by passing current between electrodes in the solutions bathing the tissue. Tissue and cell preparations were also tested with low frequency, pulsed magnetic fields by placing the biological preparation inside Helmholtz coils. For ELF dosimetry measurements in tissue preparations, electric gradients were measured directly in relation to specific axes of tissue and cell preparations. Exposures to ELF modulated 450 MHz microwave fields were conducted in two different systems, one uses a large anechoic horn chamber, the other utilizes a Crawford cell, a double-tapered coaxial system.Environmental field levels and tissue components of these fields were studied collaboratively using implantable tissue probes developed by BRH. Concurrent environmental field levels were based on measurements with other BRH probes and a NARDA microwave probe system. (ERB)
1.
Yellowfin tuna,Thunnus albacares, were trained individually to discriminate between two Earth-strength magnetic fields by differential reinforcement of a swimming response.
2.
Seven subjects, of which two were trained with a double blind procedure designed to control for the possibility of cues from the experimenter, learned to discriminate between ambient and altered fields (Figs. 1–3).
3.
Two additional fish trained with the same double blind procedure failed to discriminate between two magnetic fields in which the gradients of intensity were equal and opposite (Fig. 4).
4.
The results suggest that the responses to magnetic fields by yellowfin tuna are neurally mediated and that magnetic field detection by this species can be analyzed by the same means as other sensory modalities.
Displaced juvenile alligators,Alligator mississipiensis, were released on land in a 9 m diameter dodecagonal arena to test their ability to orient in the absence of terrestrial landmarks. Navigational ability seemed to improve with age. When displaced along a fairly direct route yearlings (age 7–14 months) compensated for their displacement, moving in the direction from the arena to their home sites. When displaced by a circuitous route, yearlings failed to compensate for their displacement, exhibiting instead simple compass orientation in a direction that would have returned them to water had they been released on land near the site where they were captured. The older juveniles were oriented in a homeward direction under all displacement and test conditions.The latter animals may have been using geomagnetic map information to select their homeward directions as the errors in their homeward bearings correlated with small deviations in the geomagnetic field's dip angle at the time of the test (1980r
s=–0.6047,P=0.0131, all testsr
s= –0.4652,P=0.0084). This effect appeared to depend on a very short-term assessment of geomagnetic conditions, as values measured 20 min before or 30 min after the tests began did not correlate with the directions the animals moved. The older juveniles appeared to use magnetically quiet hours on the night of their capture as the baseline from which to measure the geomagnetic deviations that occurred at the time of the arena test. The magnitude of the magnetic effect in the older animals suggests that the geomagnetic information may have been used to perform a map step, as small fluctuations in dip angle correlated with much larger deviations in homeward bearings. In addition, the compass-oriented yearlings and the seemingly route-based behavior of the homeward-oriented yearlings did not appear to be influenced by geomagnetic conditions. These findings have many parallels in results obtained from bird orientation studies, providing evidence that navigation may share a common basis in different vertebrate groups.
Two groups ofEurycea lucifuga were trained to move bidirectionally within separate training corridors by alternately supplying moisture to limestone-filled compartments located at each end. Both corridors were aligned horizontally along the magnetic North-South axis of the earth. One corridor was enclosed within a cube coil which rotated the magnetic field horizontally 90 clockwise, so that the group contained in this corridor moved perpendicular to the North-South axis of the magnetic field. The other corridor was in the normal earth's field so that this second group moved parallel to the horizontal North-South component of the magnetic field. Testing involved releasing both groups in the center of a cross-shaped testing assembly made up of the two training corridors. The two groups were confined together in a release device for 60 min before release. In several tests the two groups were significantly oriented (PP
Night N-acetyltransferase activity is suppressed by red and white light; the red light intensity, however, must be 10 times higher. Short light pulses also suppress night N-acetyltransferase; the higher the light intensity, the shorter the pulse is effective.
The pineal enzyme, serotonin N-acetyltransferase, exhibits a circadian rhythm of activity with nocturnal levels 15–30 times greater than those observed during a light period in the rat. This rhythm has been shown to be under visual control mediated by the sympathetic innervation to the pineal. The present study examined the participation of visual pathways and other central mechanisms in the regulation of pineal serotonin N-acetyltransferase activity. Following destruction of all visual pathways by blinding, the rhythm in enzyme activity is no longer controlled by the pattern of diurnal lighting and becomes free-running. Destruction of the primary optic tracts, the accessory optic tracts, or both of these components of the central retinal projection together, does not alter visual entrainment of the enzyme rhythm. In the absence of these pathways the only central retinal projection known to exist is a retinohypothalamic pathway branching directly off the optic chiasm to terminate bilaterally in the suprachiasmatic hypothalamic nuclei. Selective ablation of these nuclei, sparing the optic chiasm, abolishes the circadian rhythm in pineal serotonin N-acetyltransferase. This effect is mimicked by a knife cut across the medial hypothalamus caudal to the suprachiasmatic nuclei and by bilateral lesions transecting the medial forebrain bundle within the lateral hypothalamus, but a hypothalamic knife cut just rostral to the nuclei has no effect upon the rhythm. It is concluded that the retinohypothalamic projection to the suprachiasmatic nuclei is essential for maintaining the entrainment to light of the circadian rhythm in pineal serotonin N-acetyltransferase activity in the rat. In addition, the observations presented here suggest that the suprachiasmatic nuclei represent a central rhythm generator having projections directed caudally into the medial hypothalamus and into the medial forebrain bundle in the lateral hypothalamus.
Locomotor activity in hamsters, Mesocricetus auratus, in 24 hr LD cycles with light from 06.00 to 18.00 hr and simultaneously in imposed 26 hr weak magnetic cycles (ranges varying from 0.260 to 0.008 gauss), significantly reflected both periods. A 24 hr circadian pattern (ca. 200% of mean) was modulated by a concurrent 26 hr circadian pattern (range ca. 14% of mean).
In view of the reported involvement of the retinae in mediating magnetic field effects on pineal function in rats, the present study sought to test the hypothesis - based on theoretical calculations - that dim light activation of photoreceptors is necessary for magnetoreception by the retinae. Adult male rats were exposed to a single nocturnal inversion of the earth's magnetic field in the presence or absence of dim red light. Pineal gland N-acetyltransferase and hydroxyindole-O-methyltransferase activities were measured as indices of magnetosensitivity. In animals exposed to dim red light, pineal enzyme activities were inhibited significantly by the magnetic stimulus in comparison to controls (dim red light only). In contrast, the pineal response to a magnetic stimulus was absent in total darkness. These results support the notion that photoreceptor stimulation by dim light is necessary for the perception of weak magnetic fields.
In order to elucidate whether magnetic field effects on mammalian pineal function are direct, or instead indirect via retinal disturbances, acutely blinded and intact male rats were subjected to a single nocturnal magnetic stimulus. Then pineal N-acetyltransferase activity and melatonin content were assayed. Only in intact animals did the magnetic stimulus significantly reduce pineal activity, i.e. no effects were detected in blinded animals. These data point to a retinal magnetosensitivity which may serve to modulate pineal gland function.
Sprague-Dawley albino rats or Long-Evans pigmented rats were exposed during the dark phase of the daily light:dark cycle to various intensities of a sunlight-stimulating white fluorescent light (0.022, 0.044, 0.110, 0.220, 0.440 or 2.200 microW/cm2) for 30 min; pineal glands and trunk blood samples were then collected and assayed for melatonin by radioimmunoassay. Albino rats exposed to irradiances of 0.110 microW/cm2 or less had pineal melatonin levels that were not significantly different from those of unexposed animals; higher irradiances significantly (P less than 0.001) reduced melatonin levels. In contrast, as little as 0.022 microW/cm2 significantly (P less than 0.02) reduced pineal and serum melatonin levels in the pigmented rats. These results suggest that something other than the simple presence or absence of eye pigmentation is the critical factor in determining the sensitivity of the rat's pineal to retinal-mediated photic suppression of melatonin synthesis.
Recently, Schulten postulated on the basis of his experiments and quantum-mechanical calculations that variations of the strength of the earth's magnetic field may influence reactions in biological systems. In this paper groups of birds were subjected to different variations of low magnetic-field strength. The influence of these variations on the enzyme hydroxyindol-O-methyl transferase (HIOMT) was determined. HIOMT is unique to the retina and the pineal gland and seems to be involved in regulation of light-adaptation processes. A significant effect was found, which can be interpreted as being in agreement with Schulten's theory. These observations were further supported by our examination of the influence of magnetic field variation on human night-vision acuity. Whereas the magnetic influence on the avian retina may be interpreted in connection with navigation, the importance for the human retina remains to be elucidated.
Extracellular recordings from rat pinealocytes reveal different cell responses following experimental changes in the horizontal component of the ambient magnetic field. While two-thirds of the units recorded did not respond at all, one group is activated, the activation continuing after switching off the magnetic stimuli. These cells were not further activated by a second stimulus. Another group comprises cells characterized by a sustained inhibition or excitation, respectively, during magnetic stimulation. These cells could be influenced by a second stimulus. After guinea pigs and homing pigeons the rat is now the third species in which the pineal gland has been shown electrophysiologically to respond to changes of the ambient magnetic field.
In the present study the effects of artificial magnetic fields on pineal serotonin-N-acetyltransferase (NAT) activity and melatonin content in male Sprague-Dawley rats were investigated to study the secretory activity of the pineal gland. Experimental inversion of the horizontal component of the natural magnetic field, performed at night-time, led to a significant decrease of both parameters investigated. During day-time, this effect was less conspicuous. During night-time, inversion of the horizontal component is followed by a reduced pineal secretory activity for about 2 h. After 24 h exposure to the inverted horizontal component, return to the natural condition was followed by a renewed clear depression of pineal NAT activity and melatonin content, indicating that the main stimulus is not the inverted magnetic field itself but rather its change. Changing the inclination of the local magnetic field from 63 degrees to 58 degrees, 68 degrees or 78 degrees, respectively also decreased the secretory activity of the rat pineal gland.
Direct-current magnetic fields of 10 to 100 gauss cause a significant short-term reduction of the in vitro electroretinographic b-wave response in turtle retina. This response compression is not accompanied by the usual reduction in retinal sensitivity that occurs with background illumination. Furthermore, this effect is obtained only briefly after the offset of ambient lighting in the diurnal light-dark cycle of nonhibernating animals.
The purpose of this study was to test the influence of various irradiances of cool white fluorescent light on the suppression of pineal N-acetyltransferase activity (NAT) and melatonin content in hamsters. Groups of animals were exposed to light irradiances ranging from 0.00-1.86 microwatts (microW)/cm2 for 20 min during the night. Both pineal NAT and melatonin were similarly depressed by the light irradiances in a dose-related manner. The shape of the resultant dose-response curves and the calculated ED50 for NAT (0.066 microW/cm2) and melatonin (0.058 microW/cm2) were remarkably similar. These findings may be relevant to the physiological control of the pineal by natural illumination.
Recent studies have shown that extremely low-frequency (ELF) electric fields1 and radiofrequency amplitude-modulated electromagnetic fields2,3,25 can influence ion fluxes in neural tissue. Furthermore, the application of low-frequency magnetic (LFM) fields in the successful treatment of non-union fractures and pseudo-arthrosis has been widely reported4-6. Stimulated by these findings and the wide variety of effects reported in other biological systems7-10, we have set out to establish a model system for studying the biological effects of such low-frequencyfields that readily allows analysis of their mechanism of action. Clonal lines in tissue culture are an obvious choice for such a model, first, because the analysis is simplified by the presence of only one cell type and second, because the geometry of the biological sample can be specified to allow precise quantitation of applied field strengths and induced current densities. One such clonal line, designated PC12, is a likely candidate for such an approach as it expresses many properties of differentiated sympathetic neurones11-16, including calcium-dependent release of newotransmitters11,12,14. We report here that 3H-noradrenaline(NA) release from PC12 cells is stimulated by an inductively coupled 500-Hz LFM field with a magnitude comparable with certain cholinergic stimuli in this system.
From quantum mechanical and relativity principles applied to an observer using a bounded superconductive detector, any magnetic or electric field, which superficially may appear steady and homogeneous, should be perceived to have a wavelength and frequency which are functions of the size of the detector as well as of the energy density of the field. From the Heisenberg uncertainty principle, equations are derived for the uncertainties of measurement of field energy and of detector size as imposed by the principles of quantum mechanics, even if the instruments of measurement are perfect. If energy density is sufficiently low and/or size of detector is sufficiently small, then numerical values and geometries of the fields become unmeasurable by any experimental method but topological properties of the system may still be measurable. A method for estimation of size of superconductive microregions in materials or in living systems is derived. It is calculated that if superconductive microdetectors exist in living systems capable of detection of 0.1 to 1.0 gauss magnetic fields, then minimum superconductive detector diameters of 7.9 and 2.6 microns respectively are required, and these magnetic fields will have perceived effects equivalent to wavelengths of 7.9 and 2.6 microns respectively (the infrared region of light). The estimated detector sizes are comparable with the sizes of mitochondria, melanin granules, and retinal rods.
Although magnetic fields can influence biological systems, including those of man and other vertebrates, no central nervous structure has been identified that might be involved in their detection. From a theoretical point of view, the pineal organ might be such a structure for the following reasons: (1) It is involved in the regulation of circadian rhythms and is thus essential for migratory restlessness ('Zugunruhe'). Orientation at that time can be altered by an artificial magnetic field (MF) with a direction differing by 90 degrees from that of the Earth. Circadian rhythms can be inhibited from phase shifting by compensation of the Earth's MF and can be influenced by an artificial MF. (2) The pineal organ is strongly dependent on its sympathetic innervation and the sympatho-adrenergic system as a whole is sensitive to magnetic stimuli. (3) The pineal organ is a light-sensitive time-keeping organ and could form part of a combined compass--solar-clock system, which has been postulated for maintaining orientation in birds. We have therefore investigated the effect of a MF on electrophysiological activity of the guinea pig pineal organ, which is a useful system for such studies on individual cells. We report here that activity was depressed by an induced MF and restored when the MF was inverted.
Migratory birds and homing pigeons can apparently obtain directional information from the Earth's magnetic field. The effect is difficult to detect, and discussion of the possible process of magnetic field detection by birds seems so far to have foundered on the simple fact that the orientational effect of the Earth's magnetic field on a single electron spin associated with a molecule of animal tissue would be of the order 10(-8) eV--almost certainly too small to be detectable biologically. Here I direct attention to a process which would overcome this basic problem, and which also seems to provide an explanation of all the main features of published data. It is a mechanism in principle only, however, and is discussed here in no more detail than is necessary to clarify the basic ideas and to provide a basis for further investigation.
Biochemical and electrophysiological investigations on the magnetic sensitivity of the pineal organ
- S Reuss
- J Olcese
- L Vollrath
- P Semm
Reuss, S., Olcese, J., VoUrath, L. and Semm, P., Biochemical and electrophysiological investigations on the magnetic
sensitivity of the pineal organ, Proc. Germ. ZooL Sot., 78
in press.
Magnetosensititivy of the mammalian pineal gland: dependence on an optic input
- J Olcese
- S Reuss
- L Vollrath
Olcese, J., Reuss, S. and Vollrath, L., Magnetosensititivy
of the mammalian pineal gland: dependence on an optic input, Pflfigers Arch., Suppl., Vol. 403 (1985) R 41.
Magnetosensitivity of the mammalian pineal gland: dependence on an optic input
- Olcese