Steven F. Glotzbach's research while affiliated with Stanford University and other places

Publications (32)

Article
Full-text available
Evaporation of water from the skin is an important mechanism in thermal homeostasis. Resistance hygrometry, in which the water vapor pressure gradient above the skin surface is calculated, has been the measurement method of choice in the majority of pediatric investigations. However, resistance hygrometry is influenced by changes in ambient conditi...
Article
Full-text available
Hypothalamic warming induces panting in cats; in young kittens, panting is interspersed with slower breathing periods. The nature of neural mechanisms underlying these interspersed periods of nonpanting polypnea is unclear. We determined developmental characteristics of nonpanting breathing during thermal stress in kittens and adult cats. Warming e...
Article
The preoptic/anterior hypothalamic (POAH) area of 12-48-day-old unanaesthetized, unrestrained kittens was warmed with a diathermic probe to assess respiratory responses to a central thermal challenge during sleep. During quiet sleep (QS), warming of the POAH by 1.4-3.8 degrees C induced periods of tachypnoea (panting) interspersed with periods of s...
Article
The study of biological rhythms and the influence of environmental factors in the timing and synchronization of different rhythmic events have important implications for neonatal health. Preterm infants in the neonatal intensive care unit (NICU) are deprived of the patterned influences of maternal sleep, temperature, heart rate, and hormonal cycles...
Article
Full-text available
Timing and amplitude characteristics of diaphragmatic muscle activity following bilateral local warming of the preoptic area/anterior hypothalamic region (POAH) were studied during sleep in free-moving, intact adult cats. Warming of the POAH increased local brain temperature by 1.4-3.7 degrees C and elicited thermal tachypnea (panting) during quiet...
Article
The mammalian "biological clock," which resides in the hypothalamic suprachiasmatic nucleus, has an important role in both the timing and organization of sleep and in the coordination of sleep with other physiological rhythms such as temperature regulation and respiratory control. We wished to describe the development of the circadian system in nor...
Article
The role that nursery light variability may play in modulating infant biological rhythms is being studied in Stanford Medical Center's Neonatal Intensive Care (NICU) and Intermediate Care (IN) Nurseries. In this investigation, spatial and temporal variability in illuminance was determined at 20 sites within each nursery over a 5-day period. The ana...
Article
Full-text available
Evidence suggests that infant-parent co-sleeping represents the species-wide pattern of sleep in which human infant physiology evolved. The hypothesis evaluated in this manuscript is that the co-sleeping environment may foster development of optimal sleep patterning in infants and confer other benefits, including reducing the risk of the sudden inf...
Article
A clinical scoring system was used to determine retrospectively whether the severity of bronchopulmonary dysplasia (BPD) in 67 preterm infants at 21 to 27 days of age would predict the need for home supplemental oxygen or growth retardation (weight less than 5th percentile at 12 months of age). The scoring system was composed of five variables, inc...
Article
The prevalence and characteristics of periodic breathing in preterm infants were measured by 24-hour impedance pneumograms in 66 preterm infants before discharge from the nursery. Four periodic breathing parameters (percentage of periodic breathing per quiet time, number of episodes of periodic breathing per 100 minutes of quiet time, mean duration...
Article
Periodic breathing cycle duration (PCD), the time interval from the beginning of one respiratory pause to the beginning of the next pause within an episode of periodic breathing (PB), was measured by examination of 24-h impedance pneumograms in 51 preterm infants. Calculations of the SD of PCD within a given PB episode (approximately 3 s) and compa...
Article
Changes in arousal state in a euthermic mammal exert powerful influences on major neural regulatory systems. Changes in behavioral state occur at body temperature (Tb) greater than 25 degrees C during hibernation. However, no information exists regarding alterations in arousal states during deep torpor. In this study we used a combination of electr...
Article
Periodic breathing (PB) has been related to both normal and pathologic respiratory system control in infants. However, comparison of the results of separate studies has been limited by the variability in procedures used by different investigators to quantify PB. In this study we scored 15 24-hr impedance pneumograms using the criteria of Parmelee e...
Article
Periodic breathing (PB) has been studied extensively in both normal term infants and term infants presumed to be at high risk for sudden infant death syndrome (SIDS); however, little is known about the incidence and significance of PB in preterm infants. Twenty-four hour impedance pneumograms were obtained from 108 preterm infants prior to their di...
Article
Sleep characteristics were compared in young adult and aged cats over a range of environmental temperatures from 5 to 35 degrees C. Although both groups exhibited sleep disruptions as ambient temperatures decreased, transient arousals were increased at temperature extremes in the aged group compared to young adults. Declining efficiency of thermore...
Chapter
the thermoregulatory system is particularly convenient and interesting for studies of the influence of arousal state on homeostatic processes. State-related changes in thermoregulatory functions are substantial and are a general phenomenon in mammals and birds. The sleep phase of the daily rest/activity cycle is associated with decreases in metabol...
Article
Single unit activity was recorded from the suprachiasmatic nucleus (SCN) and preoptic/anterior hypothalamus (POAH) of unrestrained Wistar rats during sleep and wakefulness. Regularly firing cells, which are abundant in in vitro SCN preparations and have been considered the basis of a central neuronal oscillator, were conspicuously absent in this pr...
Article
Male Wistar rats chronically catheterized in the jugular vein were entrained to a 12 L:12 D (lights on at 07.00 h) photoperiod. [1-14C]Leucine was administered in behaving rats at either 10.00 (day) or 22.00 (night) h. After 45 min of incubation animals were sacrificed, brains frozen, sectioned, and autoradiographed. The relative amount of label in...
Article
The characteristics of the mammalian thermoregulatory system are dependent upon arousal state. During NREM sleep thermoregulatory mechanisms are intact but body temperature is regulated at a lower level than during wakefulness. In REM sleep thermoregulatory effector mechanisms are inhibited and thermal homeostasis is severely disrupted. Thermosensi...
Chapter
This chapter focuses on the interrelation between sleep and temperature regulation. The possibility of interaction between the thermoregulatory system and arousal state controlling systems requires a new look at studies on the involvement of the hypothalamus on the control of arousal states. The effects of hypothalamic lesions and electrical stimul...
Article
Unanesthetized, unrestrained kangaroo rats (Dipodomys) were studied to examine the changes in the frequency and duration of sleep states caused by long-term manipulations of hypothalamic temperature (Thy) at a thermoneutral (30 degrees C) and a low (20 degrees C) ambient temperature (Ta). A cold stimulus present in either the hypothalamus or the sk...
Article
Electroencephalogram (EEG), electrooculogram, electromyogram, and electrocardiogram were recorded from ground squirrels (Citellus beldingi and C. lateralis) during the summer and also during the hibernation season. Summer recordings revealed that the animals spent an average of 66% of the 24-h period asleep (49% of the 12-h light period and 84% of...
Article
The relationship between hypothalamic temperature and metabolic heat production was measured during wakefulness, slow-wave sleep, and paradoxical sleep in unrestrained kangaroo rats (Dipodomys). Hypothalamic temperature was manipulated with chronically implanted, water-perfused thermodes while cortical electroencephalogram, electromyogram, metaboli...
Article
Water-perfused thermodes were chronically implanted around the preoptic nuclei and hypothalamus (POH) of kangaroo rats (Dipodomys ingens). Responses in rate of metabolic heat production to manipulations of POH temperature (Thy) were measured in unanesthetized, unrestrained animals at ambient temperatures of 10, 20, 25, and 30 degreeC. The threshold...

Citations

... Well-documented energy-saving tactics are sleep, daily torpor, and prolonged torpor-also called hibernation (Davenport 1992;Davis 1976;Geiser and Ruf 1995;Heller et al. 1978). To compensate for energetic challenges imposed by relatively low T a or decreased food supply (or both), certain birds and mammals lower T b , heart rate, and respiration and fall into torpid states (Geiser and Ruf 1995). ...
... In mammals, including humans, the daily rhythms are coordinated with the external light-dark cycles by an innate timing system, the circadian clock [55]. This system has a hierarchical structure where the master pacemaker in the hypothalamic suprachiasmatic nucleus controls clocks in peripheral tissues (e.g., the heart circadian clock) by sending neuronal and hormonal signals [23,25]. The failure of synchrony between the master clock and the peripheral clocks can occur, for instance, due to an alteration of the external environment. ...
... There are several potential mechanisms whereby OSAS might alter energy expenditure. Resting energy expenditure is reduced during sleep and could be similarly affected by daytime hypersomnolence (10,11). ...
... Much of the relatively recent work on the metabolic torpor spectrum has focused on mammals (Boyles et al., 2020;Kräuchi and Deboer, 2011;Reher and Dausmann, 2021;Ruf and Geiser, 2015;van Breukelen and Martin, 2015). Energetic, neurological (electroencephalogram, EEG), transcriptomic and ecological evidence exists for a physiological continuum from shallow to deep torpor in mammals, as found in several ground squirrel species, marmots and kangaroo rats (Berger, 1984;Canale et al., 2012;Florant and Heller, 1977;Glotzbach and Heller, 1976;Heller, 1979Heller, , 1978Walker et al., 1977Walker et al., , 1979. Some bird species are known to use shallow torpor at night or when fasted, while others regularly use deep torpor (Ruf and Geiser, 2015). ...
... Thus, from these kinds of experiments, it is uncertain whether hypoxia alters the capacity to generate body heat under low temperature conditions, alters heat loss and heat production pathways differently, or reflects an underlying central mechanism. Ground squirrels and other hibernating mammals have served as model animals for elucidating underlying thermoregulatory mechanisms common to mammalian T b control (Hammel et al. 1973; Heller et al. 1974; Florant & Heller, 1977; Larkin & Heller, 1996). Not only do they exhibit a profound reduction in T b and metabolism in hypoxia (Barros et al. 2001) and a high degree of hypoxia tolerance (Drew et al. 2007; Levesque & Tattersall, 2009), they also possess a very high α (Heller, 1978, 1979), a profound, cold-activated thermogenesis from brown adipose tissue (Milner et al. 1989), and have been shown to progressively lower T th as they enter into hibernation (Heller et al. 1977). ...
... It has been shown that sleep reduces the thresholds and gains of the autonomic temperature defense mechanisms and expands the interthreshold zone (the temperature range for activation of metabolic heat production or evaporative heat loss). 63,69,73 These threshold changes are modest in SWS but much stronger in REM sleep (Box 28.1). 63,68 As a consequence, CBT and skin temperatures There are several lines of evidence supporting the notion that thermoregulation is limited or absent during REM sleep. ...
... This new finding not only is of importance to the resulting energy savings but also has implications for the mechanisms controlling thermoregulatory heat production. It appears that the sensation of incoming external heat is integrated with the hypothalamic T b set point and results in a lower threshold for increasing thermoregulatory heat production (Hammel et al., 1963;Glotzbach and Heller, 1975), causing a drop of T b . However, as P. sungorus do not lower T b when exposed to increasing T a , the sensation of the incoming radiation must be interpreted differently, perhaps via thermoreceptors oriented towards the lamp or the differential between peripheral thermoreceptors oriented towards or away from the lamp. ...
... However, whether or not global inhibition of transcription occurs remains unclear (Carey and Martin, 1996;Hittel and Storey, 2002) and transcription modulation during torpor seems to be tissue dependent (Soukri et al., 1996;van Breukelen and Martin, 2001). Torpor state during hibernation is characterized by a virtual cessation of neuronal activity in the cortical and midbrain areas (Strumwasser, 1959;South, 1972;Walker et al., 1977;Igelmund, 1995). Although the neural circuits involved in the regulation of mammalian hibernation have not been fully characterized, the onset of the torpor phase of hibernation is thought to involve hypothalamic activation and inhibition of the cerebral cortex, whereas arousals are induced by hypothalamic functions (Mihailovic et al., 1968;Kilduff et al., 1989Kilduff et al., , 1993Bitting et al., 1994;O'Hara et al., 1999;Ruby et al., 2002). ...
... Ambient temperatures outside of the TNZ can impact overall sleep duration and architecture, though note that REM sleep is far more sensitive to changes in ambient temperatures than NREM sleep (Amici et al., 2008;Cerri et al., 2005;Kumar et al., 2009;Parmeggiani, 2000;Szymusiak and Satinoff, 1981). Warm ambient temperatures often promote both REM and NREM sleep, with maximum sleep benefits at the upper end of the TNZ (Mahapatra et al., 2005;Sakaguchi et al., 1979;Schmidek et al., 1972;Sichieri and Schmidek, 1984). If temperatures are too high, however, it can lead to increased wakefulness (Kumar et al., 2009). ...
... Hibernation lies at the extreme end of a continuum of depressed activity states that begins with slow-wave sleep (FIGURE 3A) (7, 78, 114). Because humans typically spend a significant proportion of every night in slow-wave sleep with lowered metabolic rate and reduced body temperature (39,53,65,66), we can conclude that the physiological mechanisms needed to orchestrate depressed metabolism and permit a decline of core body temperature are innately present. Hibernators enter torpor from slow-wave sleep (51,117). ...