Physiological Thermoregulation Research Articles

Effects of prostaglandin antagonist SC-19220 on body temperature and on hyperthermic responses to prostaglandin E 1 and leukocytic pyrogen in the cat

Intravenous injection of SC-19220 (3–9 mg/kg) caused dose-related hypothermic responses in cats. Repeated administration of SC-19220 resulted in tolerance to its hypothermic action. During SC-19220-induced hypothermia, the hyperthermic activity of both prostaglandin E 1 and leukocytic pyrogen was reduced or abolished. Neither prostaglandin E 1 nor leukocytic pyrogen was antagonized when given shortly after recovery from SC-19220-induced hypothermia or by doses of SC-19220 which did not cause hypothermia. Although these results may indicate a role of prostaglandins in normal physiological thermoregulation, it is also possible that production of hypothermia by SC-19220 is unrelated to prostaglandin antagonism.

Pharmacokinetic analysis of pharmacological effects and drug disposition acetaminophen and 4-aminoantipyrine.

After the administration of antipyretics, the pharmacological response intensity versus time course was expressed quantitatively using a pharmacokinetic method. Acetaminophen and 4-aminoantipyrine were used as the antipyretics. After the administration of these drugs, plasma level, brain level and urinary excretion of the drug were determined as the drug disposition data. Metabolic rate, vaporization rate, rectal temperature and skin temperature were also determined as the pharmacological effects. From the observed data, an electrical analog was constructed to simulate the effects of antipyretics including physiological thermoregulation. The results indicate that the time course of pharmacological effects are reasonably simulated by a single mathematical model.

Comparative Physiology of Thermoregulation. Volume III: Special Aspects of Thermoregulation. G. Causey Whittow

Previous articleNext article No AccessNew Biological BooksComparative Physiology of Thermoregulation. Volume III: Special Aspects of Thermoregulation. G. Causey Whittow Knut Schmidt-NielsenKnut Schmidt-Nielsen Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 49, Number 3Sep., 1974 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/408130 Views: 1Total views on this site PDF download Crossref reports no articles citing this article.

Heart rate and physiological thermoregulation in a basking turtle, Pseudemys scripta elegans

1. 1. The physiological capacity of Pseudemys scripta elegans to alter The rate of body temperature change was determined by comparing rate of heating ( T a = 40°C) to rate of cooling ( T a = 5°C). 2. 2. Living turtles usually heated faster than they cooled while dead turtles heated and cooled at the same rate, which was slower than the rate of living turtles. 3. 3. Physical activity was accompanied by increased heart rate. 4. 4. Heart rate was faster during heating than during cooling. 5. 5. Evidence suggests that although heart rate was involved in the thermorelationship of the turtle, it was probably not the major factor causing the faster rate of T b change during heating than during cooling.

Temperature regulation responses of ornate box turtles, Terrapene ornata, to heat

1. 1. Eleven ornate box turtles after being preheated to 30°C core temperature were exposed to 38,41,43·3,48 and 51°C experimental environments to assess their ability to thermoregulate. 2. 2. Exposure to 38 and 41°C was not a heat stress for these turtles as evidenced by absence of restless activity, very little evaporative weight loss, no frothing and no change in heart rate. 3. 3. Frothing was adopted as an indicator of maximum physiological thermoregulation because after frothing commenced, core to air temperature gradients were established. Core to air gradients were larger in the hotter environments and onset of frothing began earlier during the heat exposure. At 48°C an 8·5°C core to air gradient was maintained for 3 hr and at 51°C a 10·5°C core to air gradient was maintained for 1·5 hr. 4. 4. Increased heart rate and evaporation of saliva and urine were effective responses which accompanied thermal balance. Weight loss appears to be a much better index of thermal stress than is heart rate.

Maximum oxygen consumption and heat loss facilitation in small homeotherms by He-O2.

ROSENMANN, MARIO, AND PETER MORRISON. Maximum oxygen consumption and heat loss facilitation in small homeotherms by He-02 . Am. J. Physiol. 226(3) : 490495. 1974.-The high thermal conductance of an 80% He-20y0 02 atmosphere was used to elicit maximum metabolism (Mmax) in moderate cold in species ranging from 7-g pygmy mice (Baiomys taylori) to 250-g white rats, including redpolls (Acanthis J?ammea), two vesper mice (Calomys d&la, C. callosus), tundra voles (Microtus oeconomus), and four strains of Mus musculus. Values slightly exceeded those in similar animals using other methods to confirm the low metabolic ratio (Mmax/M, in) in rodents (4-8 X). Submaximal values at higher temperatures defined thermal conductance in He-02 and air. In different species the ratios of these conductances ranged from 1.4 to 2.6, differences which relate to the extent and quality of the respective insulation. M,,, was obtained at 13-70°C warmer in He-02 than required in air for the same metabolic effort. Avoidance of low-temperature technology and freezing injury, elimination of treadmills and training in running, prompt attainment of M,,., (3-10 min after He-02 exposure), and obviation of shaving or wetting procedures are advantages of the present technique.

The ecological significance of thermoregulatory responses to heat stress shown by two populations of an Australian murid, Rattus fuscipes

1. 1. Both populations of Rattus fuscipes thermoregulate well at ambient temperatures below their lower critical temperatures, being assisted by low thermal conductances that vary directly with ambient temperature. 2. 2. All animals remain normothermic when subjected to temperatures within their thermoneutral zones, although they become hyperthermic at higher temperatures. Evaporative cooling is less effective as a means of delaying lethal hyperthermia than in other Australian Rattus species. 3. 3. The two populations of R. fuscipes studied show minor differences in thermoregulatory ability which correlate well with differences in their environments. 4. 4. The absence of R. fuscipes from relatively hot parts of northern Australia, whilst being abundant in cooler, southern areas, can be explained in terms of the thermoregulatory physiology of this species.

Physiology of thermoregulation in the pika, Ochotona princeps.

The mean body temperature of pika measured by radiotelemetry under field and laboratory conditions was 40.1 °C (range = 37.9–42.7) over an ambient temperature range of −9.3 to 24 °C. The maximum daily fluctuation in any one individual was less than 2.6 °C and no seasonal difference in the level of body temperature maintained was observed. Hyperthermia and death occurred after a 2-h exposure to ambient temperatures higher than 28 °C, inclusive.The basal metabolic rate was 1.53 cc O2/g h and the thermal conductance was between 0.096 and 0.050 cc O2/gh °C, 143% and 101–53%, respectively, of their predicted weight-specific values. The relatively high body temperature of pika is attributed to its high basal metabolic rate and good insulation. The low thermal conductance, which indicates a reduction of energy consumption at ambient temperatures below the lower critical temperature (21 °C), favors the overwinter survival of this species when only limited food storage is available.

Temperature Regulation of the Pyrrhuloxia and the Arizona Cardinal

Temperature Regulation of the Pyrrhuloxia and the Arizona Cardinal

Physiology of Brood Incubation in the Bumblebee Queen, Bombus vosnesenskii

ONE of the parameters affecting the rate of growth and reproduction of poikilothermic organisms is temperature. In social insects such as bumblebees1–3, which must build up their colonies rapidly to complete the cycle within a single season, the maintenance of a high nest temperature would permit the more rapid development of the poikilothermic eggs, larvae and pupae. Although heat production by bumblebees in their nests4 has been observed since the last century, little is known about nest temperature regulation in the initial stages of colony founding5–7. The queen initiating the colony in the spring perches on her brood clump containing the eggs which develop into the first set of workers1–6. I report here on the temperatures of the brood clump, the attending queen, and her thermoregulatory physiology.

Thermoregulatory Responses to Heat Stress in Four Species of Birds Weighing Approximately 40 Grams

Thermoregulatory Responses to Heat Stress in Four Species of Birds Weighing Approximately 40 Grams

Biology of Myotis thysanodes and M. lucifugus (Chiroptera: Vespertilionidae)—I. Thermoregulation

1. 1. Thermoregulatory patterns and levels of controlled body temperature ( T b) in adult female Myotis thysanodes and M. lucifugus throughout their stay in maternity colonies are significantly affected by stage of reproduction and even more by stage of pregnancy, but are not affected by abundance of body fat or age. 2. 2. It is impossible to distinguish regulating bats from conforming bats in ambient temperatures ( T a's) above 20–24°C, with bats of both species becoming partially hyperthermic above these T a's. 3. 3. Minimum T b required for initiation of flight averages 30·3 and 24·3°C, for M. lucifugus and M. thysanodes, respectively, while neonates of these two species begin to regulate at about 9 1 2 and 4 1 2 days after birth, respectively. 4. 4. Behavioral aspects of thermoregulation may be as important as physiological thermoregulation in the biology of these species.

Influence of water vapor pressure on the apparent capacity for physiological thermoregulation in reptiles

The rate of body temperature change was determined as lizards,Dipsosaurus dorsalis, were heated and cooled between 20 and 40 ° C, at various ambient water vapor pressures (WVP). While changes in WVP did not affect the rate of cooling, the rate of temperature change during heating increased exponentially with increasing WVP (Fig. 4). The ratio of the rate of body temperature change during cooling to the rate of change during heating was reduced 48% in dead animals and 36% in live animals by increasing the WVP during heating from 8 to 47 mm Hg (Fig. 5).

Temperature Regulation in Mice of the Genus Scotinomys

Body temperature and metabolism were examined in Scotinomys teguina and S. xerampelinus during 2.5-hour exposures to ambient temperatures between 0 and 35° C Thennal conductance at temperatures below thermoneutrality averaged 0.34 cc O2/g/hr/°C in the smaller species, teguina , and 0.28 cc 02/g/hr/°C in xerampelinus . The difference in mean conductance between species is statistically significant. During exposure to ambient temperatures near 35° C, deaths occurred in xerampelinus but not in teguina . In the range 0 to 5°C, hypothermia was more common in teguina than in xerampelinus . These differences in thermophysiology between the species are correlated with altitudinal distribution; xerampelinus is restricted to cool or cold highlands and teguina is found at lower, warmer altitudes. Although both are montane, tropical species, they adhere to broad patterns of thermoregulatory physiology established in studies of North American peromyscines of the genera Peromyscus, Reithrodontomys , and Baiomys .

Physiological thermoregulation in turtles

Physiological thermoregulation in turtles

Control of Temperature: Comparative Physiology of Thermoregulation . Vol. 1, Invertebrates and Nonmammalian Vertebrates. G. Causey Whittow. Academic Press, New York, 1970. x, 334 pp., illus. $17.50.

Control of Temperature: <i>Comparative Physiology of Thermoregulation</i> . Vol. 1, Invertebrates and Nonmammalian Vertebrates. G. Causey Whittow. Academic Press, New York, 1970. x, 334 pp., illus. $17.50.

Comparative Physiology of Thermoregulation. Volume 1: Invertebrates and Nonmammalian Vertebrates.G. Causey Whittow

<i>Comparative Physiology of Thermoregulation. Volume 1: Invertebrates and Nonmammalian Vertebrates.</i>G. Causey Whittow

Effect of intrahypothalamic infusion of acetylcholine on behavioural and physiological thermoregulation in the rat.

CHANGES in body temperature can be produced by local application of drugs to the preoptic and anterior area of the hypothalamus. The direction of these responses varies with the drug and the species1–4. The physiological response induced by the drug may be accompanied by a complementary behavioural thermoregulatory response: local heating of the hypothalamus, which produces physiological heat dissipation responses5, also results in decreases in rate of response for peripheral heat6,7. Similarly, local cooling produces increased rectal temperature and increased rates of response for heat7,8.

Effects of preoptic lesions on heat-escape responding and colonic temperature in the rat☆

Abstract Rats trained to bar-press to escape heat were found to increase their response rates and to show increments in both pre- and post-session colonic temperature levels after bilateral lesions were made in the “heat loss center”. The results are consistent with the thesis that rats with preoptic damage show disturbed physiological thermoregulation but generally retain enough behavioral thermoregulatory capacity to avoid death by hyperthermia. The post-operative behavioral thermoregulation, however, is not adequate to enable animals with preoptic lesions to hold their body temperatures at previous levels.

Gaseous Metabolism and Water Relations of the Zebra Finch, Taeniopygia castanotis

Gaseous Metabolism and Water Relations of the Zebra Finch, Taeniopygia castanotis