Vladimir M Kovalzon

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Verified

Vladimir verified their affiliation via an institutional email.

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• Ph.D.
• Principal Investigator at Severtsov Institute of Ecology and Evolution

Electroencephalogram (EEG), brain and abdominal temperature, and motor activity were recorded for the first time in 18 adult males of facultative hibernator, the Mongolian hamster, during hibernation under controlled laboratory conditions in winter. At room temperature, clear synchronous circadian rhythms of motor activity and body temperature were...

Aiming to answer the question of how the rest-activity cycle and subcutaneous temperature change with a decrease in ambient temperature, we studied the following species of predatory mammals: domestic cats (Felis catus, n = 4), Far Eastern forest (Amur) cats (Prionailurus bengalensis euptilura, n = 3), Eurasian lynxes (Lynx lynx, n = 3), sables (Ma...

Insects are a potential source of novel bioactive compounds with pharmaceutical applications. Our previous study revealed the presence of antioxidant system proteins in the aqueous extract of Ulomoides dermestoides Fairmaire 1893 larvae, which exhibited high antioxidant activity in vitro and improved cognitive and motor functions in aging mice. To...

The influences of dietary characteristics on sleep quality in humans currently constitute an acute problem, as harmonious interactions with the outside world in urbanized societies impose the need for a sufficient level of wakefulness, which is provided by full-length sleep. An important factor is sleep quality: fragmented sleep, regardless of dura...

Based on the analysis of extensive clinical, psychophysiological and experimental data, the author comes to the conclusion that the widespread idea of the cerebral information processing during sleep related to previous wakefulness and necessary for the formation of long-term memory and other cognitive resources of the brain is inapplicable. This h...

For most cases of endogenous depression (major depression), the hypothesis of monoamine deficiency, despite a number of limitations it faces, is still considered the most acceptable explanation. The main difficulty faced by this hypothesis is the reason for the decrease in the level of cerebral monoamines (primarily serotonin) during depression. It...

We have previously shown that the aqueous extract of the Ulomoides dermestoides darking beetle (the Tenebrionidae family) biomass contains a powerful complex of antioxidant substances of protein and non-protein nature. Considering the crucial role of ROS in the development of neurodegeneration, we set out to test the biological activity of this ext...

In humans and other vertebrates pannexin protein family was discovered by homology to invertebrate gap junction proteins. Several biological functions were attributed to three vertebrate pannexins members. Six clinically significant independent variants of the PANX1 gene lead to human infertility and oocyte development defects, and the Arg217His va...

The effect of aqueous extracts of the biomass of the adult Ulomoides dermestoides beetle on the delayed effects of the defoliant paraquat causing parkinsonism in experimental mice was evaluated. The motor activity of the animals was analyzed in behavioral tests using a rotarod and a vertical pole. The number of tyrosine hydroxylase-immunopositive n...

The effect of aqueous extracts of the biomass of the adult beetle Ulomoides dermestoides on the delayed effects of defoliant paraquat causing parkinsonism in experimental mice was evaluated. The motor activity of the animals was analyzed in behavioral tests using a rotarod and a vertical pole. The number of tyrosine hydroxylase-immunopositive neuro...

Sleep is not considered a pathological state, but it consumes a third of conscious human life. This share is much more than most optimistic life extension forecasts that biotechnologies or experimental and medical interventions can offer. Are there insurmountable physical or biological limitations to reducing the duration of sleep? How far can it b...

For the first time, continuous registration of motor activity and electroencephalogram for 40 days was carried out in four individuals of the naked mole rat (Heterocephalus glaber) in isolated conditions in the laboratory. A clear circadian rhythm of motor activity was found, with a gradual decrease during the night and an increase during the day,...

In development of the «serotonin» hypothesis of depression put forward by I.P. Lapin and G.F. Oxenkrug in 1969, the combination of the two factors is proposed which are responsible for depression formation: reduced “basal” 5-HT cerebral level and excessive duration of early morning REM sleep periods during which the release of cerebral serotonin ce...

Pannexins are a family of three proteins which play an important role in intercellular communications. This study shows that mice with knockout of the Panx1 gene(Panx1–/–) have elevated levels of movement activity and increased proportions of waking, due to decreases in slow-wave sleep, as compared with control animals, as a result of decreases in...

Objective: To evaluate an influence of intracerebral L-lactate concentration on sleep-wake cycle. Material and methods: Twenty adult male white rats preliminary implanted (under general anesthesia) with the electrodes for neocortical EEG and a single cannula to a lateral ventricle were used as subjects. A 5 µl bolus of either saline or a solutio...

Objectives. To confirm the authors’ previous suggestion that mutations in the Panx1 gene (pannexin-1) may play an important role in the development of impairments to the sleep-waking cycle. Materials and methods. Studies were carried out using mice with knockout of the Panx1 gene. Experiments used continuous 24-h EEG recording of the EEG and motor...

This review addresses contemporary experimental data on the functioning of the main neurotransmitter systems of the brain involved in arousal reactions and the maintenance of waking.

Adult male mice C57BL/6 (n = 105) were divided into five groups. The first group served as a control. In the 2nd–5th groups, the animals were treated subcutaneously with 40 mg/kg of proneurotoxin MPTP (methylphenyltetrahydropyridine), which forms a state similar to the initial stage of Parkinson’s disease over a 2-week period. Mice of groups 3–5 da...

Aim: To test the hypothesis of a possible role of the Panx1 (pannexin-1) mutation in changing the sleep - wake cycle. Material and methods: Continuous 24 h recording of the EEG and movement activity in Panx1 knockout and wild type mice was performed. Results and conclusion: A significant increase in wake percentage at the expense of a decrease...

During brain homeostasis, both neurons and astroglia release ATP that is rapidly converted to adenosine in the extracellular space. Pannexin-1 (Panx1) hemichannels represent a major conduit of non-vesicular ATP release from brain cells. Previous studies have shown that Panx1−/− mice possess severe disruption of the sleep-wake cycle. Here, we review...

Five groups of C57Bl/6JSto mice (groups 1–5) were tested on a vertical pole two weeks after s.c. administration (groups 2–5) of the proneurotoxin methylphenyltetrahydropyridine (MPTP) at a dose of 40 mg per kg, which at this time induces sensorimotor impairments similar to the early stage of Parkinson’s disease. Mice of group 1 served as controls....

Novel experimental data concerning the function of the basic cerebral neuromediator systems which take part in arousal reactions and waking maintenance are regarding in the review.

There were two stages in the history of the studies on ascending reticular activating system of the brain (ARAS). The first stage began with the ARAS discovery by Magoun and Moruzzi and the following investigations using the methods of stimulation and lesion at that time mainly in acute cats. These studies led to the hypothesis of a “diffuse” and “...

Computer programs for the automatic analysis of the electroencephalogram (EEG) from humans and animals have entered wide use and are successfully employed in many areas of physiological research. They are of particular value for sleep studies, as traditional expert analysis of polysomnograms (PSG) is very laborious. The aim of the present work was...

Pannexins are membrane channel proteins that play a role in a number of critical biological processes (Panchin et al., 2000; Shestopalov, Panchin, 2008). Among other cellular functions, pannexin hemichannels serve as purine nucleoside conduits providing ATP efflux into the extracellular space (Dahl, 2015), where it is rapidly degraded to adenosine....

Circadian disturbances related to Parkinson’s disease are reviewed, and possible pathogenetic mechanisms are discussed. The role of dopaminergic system degeneration in the development of circadian dysfunction is emphasized. The accumulation of α-synuclein in the suprachiasmatic nucleus is considered as a possible mechanism of circadian dysfunction...

Circadian disturbances related to Parkinson’s disease are reviewed, and possible pathogenetic mechanisms are discussed. The role of dopaminergic system degeneration in the development of circadian dysfunction is emphasized. The accumulation of α-synuclein in the suprachiasmatic nucleus is considered as a possible mechanism of circadian dysfunction...

Background: Previously, we have shown that transgenic cells bearing the GDNF gene with deleted pre- and pro-regions (mGDNF) can release transgenic GDNF. The medium conditioned by transgenic cells with mGDNF induced axonal growth in rat embryonic spinal ganglion in vitro. Here we demonstrate a neurotrophic effect of mGDNF on PC12 cells in vitro as...

Mice with previously implanted electrodes for recording the cortical electroencephalogram and electromyograms underwent all-day baseline videopolysomnography with a 12/12 light cycle, after which animals received doses of 24 or 48 mg/kg of the neurotoxin precursor MPTP (1-methyl-4-phenyl-1.2.3.7-tetrahydropyridine) or physiological saline (controls...

Five groups of C57Bl/6JSto mice (groups 1-5) were tested on a vertical pole 2 weeks since subcutaneous administration of proneurotoxin MPTP (40 mg per kg b. w.) to groups 2-5. Group 1 served as control. It is known that this MPTP dosage forms within 2 weeks sensorimotor disturbances similar to the initial stage of Parkinson's disease. One week befo...

Actuality of the studies of sleep-wakefulness cycle and its disorders creates the necessary prerequisites for a new medical field, the clinical somnology or sleep medicine. There are definitions for such terms as REM and NREM (non-REM) sleep in this review. Other main terms: cycles, phases and stages of sleep, are described. Cerebral waking mechani...

Abstract—The results of study on the sleep–wakefulness cycle in experimental models of the preclinical and early clinical stages of Parkinson’s disease are presented and compared with clinical examples. The conclu� sion is made that the enhancement of behavioral activity and decrease in the total duration of the slow�wave and paradoxical sleep in m...

Computer programs for automatic sleep scoring of human and animals EEG records are widely used in many branches of physiological research. They are particularly useful during the sleep research because the traditional methods requiring human expert scoring of long records are very laborious and time-consuming. The aim of this work was to investigat...

The structure, morphological and neurochemical bindings ofhistaminergic system of the brain as one of the most important mechanisms of waking maintenance, are regarded. The biochemistry of histamine turnover and histamine receptors are briefly described. The special role of the relation between histamine and orexin/hypocretin systems is stressed. S...

A group of mice with preliminary implanted (under general anesthesia) electrodes for cortical EEG and nuchal EMG was subjected to continuous baseline 24-hr video and digital polysomnographic recording with the 12/12 light/dark schedule, and then injected subcutaneously with 24 or 48 mg/kg of MPTP toxin or (the control group) saline. The recordings...

Introduction The search for early markers of Parkinson’s disease (PD) is one of the most important problems in the struggle against neurodegenerative illnesses. It is well known that large set of sleep-wake disorders occur with PD, including RBD, daytime sleepiness, night sleep disturbance etc. The nature of these is generally unknown. Not infreque...

The structure and the morphological and neurochemical connections of the histaminergic system of the brain, which plays one of the most important roles in maintaining wakefulness, are considered. The biochemistry of histamine metabolism and histamine receptors is briefly described. The special role of the relation between the histamine system and o...

Parkinson’s disease (PD) is one of the most socially relevant illnesses. Sleep disturbances in PD are common and manifold; they are present, according to different data, in 45–98% of all patients and include insomnia, parasomnia, hypersomnia, and other symptoms. Many of these symptoms appear several years before the development of movement disorder...

Disputable questions of modern somnology, the neuroscience branch involving wakefulness-sleep cycle regulation, circadian and diurnal rhythms and other related problems, are regarded. Among them are the questions of the extent of similarity of the alternation of active-rest periods in the nematode, fruit fly, zebrafish and other simple model organi...

The effects of sleep deprivation produced using a carousel method on the consolidation of spatial memory were studied in rats (male Wistar rats) after one-day training using the Frick et al. protocol (2000) in a Morris water maze. Data were obtained providing evidence that the memory trace after rapid 3-h training was retained for one day. Sleep de...

The C57BL/6 mice were subjected to a chronic combined stress which resulted in the induction of a depressive-like state. The occurrence of a depressive-like state was defined by a decrease in sensitivity to the reward determined by the diminished preference of sweetened solutions over regular drinking water. Such decrease is generally considered as...

Brief anatomical, physiological and neurochemical basics of the regulation of wakefulness, slow wave (NREM) sleep and paradoxical (REM) sleep are regarded as representing by the end of the first decade of the second millennium.

The notions on the anatomical, physiological and neurochemical mechanisms of the regulation of wakefulness, slow wave (NREM) sleep and paradoxical (REM) sleep formed by the end of the first decade of the 21st century are briefly reviewed. Keywordswakefulness–slow wave (NREM) sleep–paradoxical (REM) sleep–orexin/hypocretin

The effect of sleep deprivation by 'carousel' method on spatial memory consolidation in a Morris water maze was studied in Wistar male rats after one-day learning (in accordance to a protocol by Frick et al., 2000). It was found that after fast 3-hr learning the memory trace retains during 24-hr. Twenty four hour sleep deprivation followed learning...

Main achievements in general and molecular genetics of sleep, especially NREM sleep, are regarded. Among them, discovery of such heredity disorders, as FFI, FASPS and DSPS, the finding of genetic hallmarks of sleep EEG, etc.

Chronic experiments on laboratory rats with implanted electrodes for recording neocortical and hippocampal EEG and cervical muscle electromyogram traces were performed to study the effects of strong treatments inducing diffuse damage to brain tissue on subsequent sleep. Four different experimental models were used: one "chronic" (generalized cerebr...

Studies on rats divided into two groups with different sensitivities on the basis of manifest convulsive activity in response to pentylenetetrazol kindling showed that both "tolerant" and "sensitive" rats showed convulsive discharges on EEG traces. However, as compared with values in "tolerant" rats, the number of convulsive discharges in "sensitiv...

A short note about the life and personality of Maria Manasseina (also known as Marie von Manassein, Marie de Manaceine), a Russian woman-doctor of the second half of the nineteenth century, a pioneer in biochemistry and experimental somnology.

Effects of strong stress inducing diffuse damage of the brain tissue on subsequent sleep were studied in rats preliminary implanted with chronic electrodes for the neocortical and hippocampal EEG as well as EMG of the neck muscles. An acute and three chronic experimental models were used: general cerebral ischemia induced by a permanent unilateral...

Rats were subjected to pentylenetetrazol kindling and divided into 2 groups according to their ability to demonstrate convulsions: the "sensitive" and "tresistant" rats groups. Both groups demonstrated EEG afterdischarges; however, the number of the EEG seizures in "sensitive" rats was 60% higher, the latency by 45 sec longer, and the total duratio...

In order to induce the state of anhedonia, a key symptom of depression, mice were subjected to a one-month stress procedure comprised of various stressors. Anhedonic state was defined by a reduction of preference for sucrose solution over tap water. Conventional cortical and neck-muscle electrodes were implanted to control and stressed animals unde...

Depression is a mental illness with a core feature of anhedonia, a decreased ability to experience pleasures. Depression is also characterized by specific changes in the sleep structure. Stress can precipitate depressive disorders, which are accompanied by characteristic sleep impairment and, at the same time, affect sleep during other stress-relat...

To test the hypothesis that certain peptide complexes can cause effects that cannot be exerted by the same peptides when used separately, the effect of a tripeptide combination of delta sleep-inducing peptide (DSIP), neuropeptide tyrosine (NPY), and atrial natriuretic peptide/factor (ANP/ANF) was studied. In accordance with theoretical vector analy...

Delta sleep-inducing peptide (DSIP) was isolated from rabbit cerebral venous blood by Schoenenberger-Monnier group from Basel in 1977 and initially regarded as a candidate sleep-promoting factor. However, the link between DSIP and sleep has never been further characterized, in part because of the lack of isolation of the DSIP gene, protein and poss...

Irradiation of animals with ultrashort impulses of ultra-broadband magnetic irradiation with an impulse repetition frequency of 6 Hz for 1 h induced changes in the spectral composition of cerebral cortex electrical activity in rats, measured over the 5 min immediately after irradiation, as compared with controls. In particular, there was suppressio...

1-hour exposure to ultra-short impulse low-frequency (6 Hz) superbroad band electromagnetic radiation altered cortical EEG in rats just after the exposure and increased the paradoxical sleep in rabbits within 16-22 hours following the radiation.

The sleep-inducing activity of Delta Sleep-Inducing Peptide (DSIP) and its 13 synthetic analogs has been studied on rabbits with preliminary implanted electrodes. The peptides were injected into the lateral ventricle of cerebrum. Polygraphic computer monitoring of sleep-wake states was carried out at daytime for 7-12 h. DSIP and most analogs had no...

The sleep-inducing activity of Delta Sleep-Inducing Peptide (DSIP) and its 13 synthetic analogs has been studied on rabbits with preliminary implanted electrodes. The peptides were injected into the lateral ventricle of cerebrum. Polygraphic computer monitoring of sleep–wake states was carried out at daytime for 7–12 h. DSIP and most analogs had no...

Basal sleep amounts in adrenalectomized rats (AdX), as compared to intact animals, exhibit a significant increase in slow-wave sleep (SWS), a tendency towards an increase in paradoxical sleep (PS), and circadian rhythms (SWS and PS) flattened in amplitude. An immobilization stress (IS) of 1 h, imposed on AdX rats at the beginning of the dark period...

Polygraphic recordings were performed during 12-h dark period in 18 adrenalectomized rats with implanted electrodes for ECoG and EMG under normal conditions and following 1-h immobilization period. The exposure of rats to emotional immobilization stress evoked a highly significant increase in sleep which was especially pronounced for the slow wave...

Effects of muramyl peptides from bacterial cell walls (MDP and GMDP), their fragments, steric isomers and structural analogues were studied on sleep in rabbits. An increase in the SWS, decrease in PS, rise in body temperature were found following minimal doses, whereas pathological responses in the EEG and sleep as well as pyrogenic effects occurre...

Peptide [D-AIa2]DSIP markedly increases the representation of NREM and REM sleep delayed by several hours from the onset of infusion and lasting after the infusion till the end of the 12-hour night period in a chamber. Peptide [D-Tyr1]DSIP increases NREM sleep during hours IV and XI of recordings. Analogs of these peptides have no noticeable effect...

Muramyl peptides (MPs) possess immunostimulatory, pyrogenic and somnogenic activities. The structural requirements of MPs for each of these activities are different though certain MPs, e.g. muramyl dipeptide (NAM-L-ala-D-isogln) possess all three activities. Several MPs are proposed for use as immune adjuvants; somnogenic and pyrogenic activities w...

Hypnogenic effects of 3 DSIP analogs with a higher stability against aminopeptidase activity have been studied in rabbits and rats using intraventricular administration (injections and infusions). An analog (D-Ala-2) DSIP augmented slow wave and paradoxical sleep within the 5th, 8th and 11th hours of the recording period. An analog (D-Val-2) DSIP m...

Unihemispheric and bihemispheric sleep deprivation were performed in bottlenose dolphins. One brain hemisphere was capable of being deprived of delta (0.5-3.0 Hz) sleep in the former condition. Here, an increase in sleep pressure was observed during sleep deprivation in the deprived hemisphere. In the recovery sleep, following unihemispheric sleep...

Effects of intracerebroventricular administration of 3 DSIP analogues with higher stability against proteolysis, on subsequent sleep were studied in rabbits and rats previously implanted with electrodes and cannulas. Significant increase of total sleep time (mainly due to slow wave sleep) after administration of the peptides (D-Trp1) DSIP and (D-Ty...

Delta Sleep-Inducing Peptide (DSIP) was not previously found to possess hypnogenic properties. Its analogue (D-TrpI)DSIP was more stable against aminopeptidases. Its intracerebrovascular administration in doses of 0.7, 7 and 70 micrograms/kg body weight induced a significant increase in slow wave sleep (by 40%; p less than 0.01, U-test) and rectal...

DSIP and its analogues, [D-Trp1]-DSIP, [D-Tyr1]-DSIP, and [D-Trp1]-DSIP1-6, were injected ICV (7 nmol/kg) into rats at dark onset, and the sleep-wake activity was recorded during the 12-hr dark period and the subsequent 12-hr light period. The effects were evaluated with respect to baseline records obtained after artificial CSF injections. DSIP did...

Eighty-eight adult white rats were divided into 9 groups. Groups 1 and 2 served as controls. The rats of Group 3 were repeatedly aroused during 4 days at the very onset of each REM-sleep period by direct midbrain reticular formation stimulation. This deprivation decreased the daily amount of REM-sleep by 70%, while slow-wave sleep was reduced by 10...

88 adult male rats were divided into 9 groups. Group I and II served as controls. The rats of group III were repeatedly aroused during 4 days at the very onset of each paradoxical sleep period by direct MRF stimulation. This deprivation reduced the daily amount of paradoxical sleep by 70%, while the slow wave sleep was reduced by 10% only. In group...

Rats were repeatedly arused from REM sleep by the stimulation via implanted midbrain reticular electrodes. The 4-day seprivation reduced REM sleep by 50% whereas the slow-wave sleep was only reduced by 10%. There was no evidence of a disruption in the animal behaviour during the deprivation and no changes of emotional responsiveness in the "open-fi...