Thermoregulatory control during pregnancy and lactation in rats

1997 ◽  
Vol 83 (3) ◽  
pp. 837-844 ◽  
Author(s):  
Heather L. Eliason ◽  
James E. Fewell
Keyword(s):  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Thermal Conductance ◽  
Thermoregulatory Response ◽  
Linear Temperature ◽  
Metabolic Chamber ◽  
Linear Temperature Gradient ◽  
Thermoneutral Zone ◽  
Pregnancy And Lactation ◽  
Near Term

Eliason, Heather L., and James E. Fewell.Thermoregulatory control during pregnancy and lactation in rats. J. Appl. Physiol. 83(3): 837–844, 1997.—Although the mechanisms remain unknown, maternal core temperature (Tc) decreases near term of pregnancy and is increased throughout lactation in rats. The purpose of our present experiments was to determine whether pregnancy and lactation shift the thermoneutral zone of rats and to investigate whether the changes in maternal Tcduring pregnancy and lactation result from “forced” or “regulated” thermoregulatory responses. Conscious, chronically instrumented nonpregnant and pregnant and lactating rats were studied both in a thermocline (a chamber with a linear temperature gradient from 12 to 36°C) and in a metabolic chamber to determine the influence of pregnancy and lactation on selected ambient temperature as well as the thermoregulatory response to changes in ambient temperature. We found that selected ambient temperature, oxygen consumption, and thermal conductance did not change in rats studied in a thermocline as Tc decreased near term of pregnancy. There was, however, a downward shift in the thermoneutral zone of rats studied in a metabolic chamber near term of pregnancy. During lactation, selected ambient temperature decreased in rats studied in a thermocline as oxygen consumption and Tc increased. The thermoneutral zone of lactating rats was not different from that of nonpregnant animals. Thus our data provide evidence that the decrease in Tc near term of pregnancy in rats results from a regulated thermoregulatory response, whereas the increase in Tc during lactation results from a forced thermoregulatory response.

Thermoregulation in rats during early postnatal maturation: importance of nitric oxide

2003 ◽  
Vol 285 (6) ◽  
pp. R1366-R1372 ◽  
Author(s):  
Sulleman S. Malik ◽  
James E. Fewell
Keyword(s):  
Nitric Oxide ◽  
Oxygen Consumption ◽  
Methyl Ester ◽  
Ambient Temperature ◽  
Oxide System ◽  
Peak Oxygen Consumption ◽  
Linear Temperature ◽  
Postnatal Maturation ◽  
Metabolic Chamber ◽  
Rat Pups

Experiments were carried out to determine the role of nitric oxide in mediating autonomic and behavioral thermoregulatory control in rat pups on postnatal days 1-2, 5-6, and 10-11. For an experiment, each pup received a subcutaneous injection of vehicle, NG-nitro-d-arginine methyl ester (d-NAME; 100 mg/kg), or NG-nitro-l-arginine methyl ester (l-NAME; 100 mg/kg) before being placed in a metabolic chamber or in a thermocline with a linear temperature gradient of 23 to 43°C. In the metabolic chamber, oxygen consumption and core temperature were measured as ambient temperature was decreased from 40 to 15°C over a 60-min period. Decreasing ambient temperature elicited an increase in oxygen consumption in all age groups that received vehicle or d-NAME. The lower critical temperature and peak oxygen consumption upon exposure to cold after vehicle were 41 ± 10 ml · kg-1 · min-1 at 30°C, 43 ± 12 ml · kg-1 · min-1 at 28°C, and 55 ± 11 ml · kg-1 · min-1 at 25°C in the 1- to 2-, 5- to 6-, and 10- to 11-day-old pups, respectively. Administration of l-NAME abolished the oxygen consumption response to cold in the 1- to 2- and 5- to 6-day-old pups and significantly attenuated the oxygen consumption response to cold in the 10- to 11-day-old pups. Selected ambient temperature in the thermocline was not significantly affected by prior administration of d-NAME or l-NAME compared with vehicle. Thus our data provide evidence that the nitric oxide system plays a role in mediating autonomic but not behavioral thermoregulatory control in rat pups during early postnatal maturation.

Autonomic and behavioral thermoregulation in guinea pigs during postnatal maturation

1997 ◽  
Vol 83 (3) ◽  
pp. 830-836 ◽  
Author(s):  
James E. Fewell ◽  
Maria Kang ◽  
Heather L. Eliason
Keyword(s):  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Ambient Temperature ◽  
Guinea Pigs ◽  
Thermal Environment ◽  
Thermal Conductance ◽  
Behavioral Thermoregulation ◽  
Postnatal Maturation ◽  
Metabolic Chamber ◽  
Oxygen Requirements

Fewell, James E., Maria Kang, and Heather L. Eliason.Autonomic and behavioral thermoregulation in guinea pigs during postnatal maturation. J. Appl. Physiol. 83(3): 830–836, 1997.—Serial experiments were carried out on seven chronically instrumented Hartley-strain guinea pigs at 1, 3, and 5 wk of age to define their autonomic and behavioral thermoregulatory profiles and to test the hypothesis that they have the mechanisms in place shortly after birth that allow them to optimize their energy expenditure for thermoregulation by selecting a thermal environment that requires the lowest metabolic oxygen requirements. Each animal was studied in both a thermocline to determine selected ambient temperature and in a metabolic chamber to determine the thermoregulatory response to forced changes in ambient temperature. In the thermocline, the guinea pigs at all postnatal ages selected an ambient temperature that placed core temperature, oxygen consumption, thermal conductance, heart rate, and respiratory rate at levels comparable to those observed at ambient temperatures in which minimal oxygen consumption occurred in the metabolic chamber. Thus our experiments provide evidence that guinea pigs have the neurophysiological mechanisms in place shortly after birth that allow them to optimize their energy expenditure for thermoregulation by selecting a thermal environment that corresponds to the lowest metabolic oxygen requirements.

Influence of pregnancy on the febrile response to ICV administration of PGE1 in rats studied in a thermocline

1997 ◽  
Vol 82 (5) ◽  
pp. 1453-1458 ◽  
Author(s):  
Heather L. Eliason ◽  
James E. Fewell
Keyword(s):  
Ambient Temperature ◽  
Body Core Temperature ◽  
Prostaglandin E ◽  
Thermoregulatory Response ◽  
Febrile Response ◽  
Pregnant Rats ◽  
Thermoneutral Zone ◽  
Brown Adipose ◽  
Body Core ◽  
Near Term

Eliason, Heather L., and James E. Fewell. Influence of pregnancy on the febrile response to ICV administration of PGE1 in rats studied in a thermocline. J. Appl. Physiol. 82(5): 1453–1458, 1997.—Rats near term of pregnancy have an attenuated febrile response to intracerebroventricular (ICV) injection of prostaglandin E1(PGE1) when they are studied at an ambient temperature below their thermoneutral zone. Given that nonshivering thermogenesis in brown adipose tissue is impaired in rodents near term of pregnancy, it is possible that the attenuated febrile response is forced by impairment of this component of the autonomic thermoregulatory response. If this were the case, then near-term pregnant rats should develop a “normal” fever after PGE1 administration if they were studied in a thermocline where they could utilize behavioral as well as autonomic thermoregulatory effectors to increase their body core temperature (Tbc). Experiments were, therefore, carried out on 13 nonpregnant and 14 pregnant chronically instrumented rats in a thermocline (temperature gradient 10–40°C) to investigate their Tbc responses to ICV injection of PGE1. ICV injection of 0.2 μg PGE1 produced significant increases in Tbc and fever index in both nonpregnant and pregnant animals ( day 19 of gestation); the increases, however, were significantly attenuated in the pregnant compared with the nonpregnant rats. Behavioral (e.g., selected ambient temperature) and autonomic (e.g., oxygen consumption) thermoregulatory effectors were activated to increase Tbc after ICV PGE1 in both groups of animals, but the duration of activation was shortened in pregnant compared with nonpregnant rats. The abbreviated thermoregulatory effector responses and the resulting attenuated febrile response to PGE1 in the pregnant rats may have resulted from a pregnancy-related activation of an endogenous antipyretic system.

The metabolic rate and thermal conductance of the eastern barred bandicoot (Perameles gunnii) at different ambient temperatures

2003 ◽  
Vol 51 (6) ◽  
pp. 603 ◽  
Author(s):  
M. P. Ikonomopoulou ◽  
R. W. Rose
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Conductance ◽  
The Body ◽  
High Metabolic Rate ◽  
Ambient Temperatures ◽  
Reduced Body ◽  
Thermoneutral Zone ◽  
Reproductive Females

We investigated the metabolic rate, thermoneutral zone and thermal conductance of the eastern barred bandicoot in Tasmania. Five adult eastern barred bandicoots (two males, three non-reproductive females) were tested at temperatures of 3, 10, 15, 20, 25, 30, 35 and 40°C. The thermoneutral zone was calculated from oxygen consumption and body temperature, measured during the daytime: their normal resting phase. It was found that the thermoneutral zone lies between 25°C and 30°C, with a minimum metabolic rate of 0.51 mL g–1 h–1 and body temperature of 35.8°C. At cooler ambient temperatures (3–20°C) the body temperature decreased to approximately 34.0°C while the metabolic rate increased from 0.7 to 1.3 mL g–1�h–1. At high temperatures (35°C and 40°C) both body temperature (36.9–38.7°C) and metabolic rate (1.0–1.5 mL g–1 h–1) rose. Thermal conductance was low below an ambient temperature of 30°C but increased significantly at higher temperatures. The low thermal conductance (due, in part, to good insulation, a reduced body temperature at lower ambient temperatures, combined with a relatively high metabolic rate) suggests that this species is well adapted to cooler environments but it could not thermoregulate easily at temperatures above 30°C.

Temperature regulation and cold acclimation in the golden hamster

1965 ◽  
Vol 20 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Hermann Pohl
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Cold Acclimation ◽  
Heat Production ◽  
Golden Hamster ◽  
Thermal Conductance ◽  
Muscular Activity ◽  
The Body ◽  
Ambient Temperatures

Characteristics of cold acclimation in the golden hamster, Mesocricetus auratus, were 1) higher metabolic rate at -30 C, 2) less shivering when related to ambient temperature or oxygen consumption, and 3) higher differences in body temperature between cardiac area and thoracic subcutaneous tissues at all ambient temperatures tested, indicating changes in tissue insulation. Cold-acclimated hamsters also showed a rise in temperature of the cardiac area when ambient temperature was below 15 C. Changes in heat distribution in cold-acclimated hamsters suggest higher blood flow and heat production in the thoracic part of the body in the cold. The thermal conductance through the thoracic and lumbar muscle areas, however, did not change notably with lowering ambient temperature. Marked differences in thermoregulatory response to cold after cold acclimation were found between two species, the golden hamster and the thirteen-lined ground squirrel, showing greater ability to regulate body temperature in the cold in hamsters. hibernator; oxygen consumption— heat production; body temperature — heat conductance; muscular activity — shivering; thermoregulation Submitted on July 6, 1964

Photoperiodic effects on body size and energetics of the collared lemming, Dicrostonyx groenlandicus

1988 ◽  
Vol 66 (4) ◽  
pp. 835-841 ◽  
Author(s):  
P. S. Reynolds ◽  
D. M. Lavigne
Keyword(s):  
Body Size ◽  
Ambient Temperature ◽  
Core Temperature ◽  
Thermal Conductance ◽  
Seasonal Patterns ◽  
Metabolic Rates ◽  
Ambient Temperatures ◽  
Thermoneutral Zone ◽  
Dicrostonyx Groenlandicus ◽  
Phylogenetic Adaptation

Resting metabolic rates of adult collared lemmings, Dicrostonyx groenlandicus, acclimated from weaning to either long, "summer" (22L:2D) or short, "winter" (2L:22D) photoperiod at 15 °C were examined as a function of ambient temperature. Winter morphs were significantly heavier than summer morphs (73.8 ± 7.7 (SD) and 54.5 ± 7.2 (SD) g, respectively). However, there were no differences in mass-specific metabolic rates between treatments at 15 and 20 °C. At low ambient temperatures (0 and −10 °C), metabolic rates of summer morphs were significantly higher than those of winter morphs, indicating a shift in the thermoneutral zone with photoperiod acclimation. There were no significant differences in core temperature between morphs at any ambient temperature. Thermal conductance of winter morphs was significantly lower (0.05 mL O2 (g∙h∙°C)−1) than that of summer morphs (0.09 mL O2 (g∙h∙°C)−1). Comparisons with other myomorph rodents do not support the contention that lemmings have unusually high metabolic rates. However, minimal thermal conductances of lemmings were much lower than expected on the basis of body size. These data suggest that although lemmings may differ in seasonal patterns of energetics from other microtines, there is little evidence to support the assertion that high rates of metabolism are characteristic of all microtines, or that observed basal rates represent a phylogenetic adaptation to cold.

Thermal energetics of Nyctophilus geoffroyi (Chiroptera : Vespertilionidae) at the southern limits of its distribution

2003 ◽  
Vol 51 (1) ◽  
pp. 43 ◽  
Author(s):  
K. J. Dixon ◽  
R. W. Rose
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Rate ◽  
New South ◽  
Thermal Conductance ◽  
Reproductive Condition ◽  
Thermoneutral Zone ◽  
Downward Shift ◽  
South Wales ◽  
Thermal Energetics

The energetics of the lesser long-eared bat, Nyctophilus geoffroyi, at the southern limits of its distribution was examined to determine whether this species shows any latitudinal variation in this aspect of its physiological ecology. Estimates of metabolic rate were obtained from the oxygen consumption of adult bats in a non-reproductive condition. Values for the thermoneutral zone were similar but thermal conductance was lower than for bats from mainland of Australia. Euthermic body temperature was higher (37.4 ± 0.2°C) and the ambient temperature at which N. geoffroyi entered torpor has a downward shift of 10°C at the southern limits of its distribution. The basal metabolic rate (1.12 ± 0.14 mL O2 g–1 h–1) also was lower than in lower latitudes. Thermal conductance of the bats in Tasmania was lower than that found in New South Wales or Western Australia (0.29 v. 0.38–0.39 mL O2 g–1 h–1 °C–1). All of these differences are apparently adaptations to a cooler environment.

scholarly journals Coordination of autonomic and behavioral thermoregulatory responses during exposure to a novel stimulus in rats

1998 ◽  
Vol 275 (3) ◽  
pp. R673-R676 ◽  
Author(s):  
Karin E. Dymond ◽  
James E. Fewell
Keyword(s):  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Psychological Stress ◽  
Core Temperature ◽  
Intraperitoneal Injection ◽  
Temperature Response ◽  
Metabolic Chamber ◽  
The Core ◽  
Duration Magnitude ◽  
Effector Mechanisms

The induction of psychological stress in rats is accompanied by an elevation of core temperature. Our experiments were carried out to determine whether the latency, duration, magnitude, or effector mechanisms of the core temperature response to psychological stress would be altered when rats were allowed to use behavioral as well as autonomic thermoregulation. Core temperature, oxygen consumption, and ambient temperature were measured in adult rats before and after handling and a sham intraperitoneal injection. Seven rats were studied in a thermocline (gradient of 7 to 42°C) and eight rats were studied in a metabolic chamber (25°C). The rats studied in the thermocline selected a warm ambient temperature following the sham intraperitoneal injection and exhibited an increase in core temperature of shorter latency, greater magnitude, and greater duration than those studied in the metabolic chamber. The rats studied in the metabolic chamber exhibited an oxygen consumption response of greater magnitude and duration than the animals studied in the thermocline. Thus the characteristics in addition to the effector mechanisms of the core temperature response to psychological stress are altered when rats are allowed to use behavioral as well as autonomic thermoregulatory effectors.

scholarly journals Microfluidic Platform for Analyzing the Thermotaxis of C. elegans in a Linear Temperature Gradient

2017 ◽  
Vol 33 (12) ◽  
pp. 1435-1440 ◽  
Author(s):  
Sunhee YOON ◽  
Hailing PIAO ◽  
Tae-Joon JEON ◽  
Sun Min KIM
Keyword(s):  
Temperature Gradient ◽  
Linear Temperature ◽  
Microfluidic Platform ◽  
C Elegans ◽  
Linear Temperature Gradient

Body temperature regulation and oxygen consumption in young chicks fed thyroid hormone

1991 ◽  
Vol 69 (7) ◽  
pp. 1842-1847 ◽  
Author(s):  
Gregory K. Snyder ◽  
Joseph R. Coelho ◽  
Dalan R. Jensen
Keyword(s):  
Oxygen Consumption ◽  
Thyroid Hormone ◽  
Body Temperature ◽  
Ambient Temperature ◽  
Cold Exposure ◽  
Elevated Serum ◽  
Body Temperatures ◽  
Serum Thyroid Hormone ◽  
Regulate Body Temperature ◽  
Young Chicks

In chicks the ability to regulate body temperature to adult levels develops during the first 2 weeks of life. We examined whether the ability of young chicks to regulate body temperature is increased by elevated levels of the thyroid hormone 3,3′5-triiodothyronine. By 13 days following hatch, body temperatures of chicks were not significantly different from those expected for adult birds. Furthermore, at an ambient temperature of 10 °C, 13-day-old control chicks were able to maintain body temperature, and elevated serum thyroid hormone levels did not increase rates of oxygen consumption or body temperature above control values. Six-day-old chicks had body temperatures that were significantly lower than those of the 13-day-old chicks and were not able to regulate body temperature when exposed to an ambient temperature of 10 °C. On the other hand, 6-day-old chicks with elevated serum thyroid hormone had significantly higher rates of oxygen consumption than 6-day-old control chicks, and were able to maintain constant body temperatures during cold exposure. The increased oxygen consumption rates and improved ability to regulate body temperature during cold exposure were correlated with increased citrate synthase activity in skeletal muscle. Our results support the argument that thyroid hormones play an important role in the development of thermoregulatory ability in neonate birds by stimulating enzyme activities associated with aerobic metabolism.

Sign in / Sign up

Export Citation Format

Share Document