Development of thermoregulation in Richardson's ground squirrel, Spermophilus richardsonii

1980 ◽  
Vol 58 (5) ◽  
pp. 890-895 ◽  
Author(s):  
Teresa M. Dolman
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Ground Squirrel ◽  
Metabolic Response ◽  
Thermal Conductance ◽  
Subsequent Growth ◽  
Normal Body Temperature ◽  
Normal Body ◽  
Spermophilus Richardsonii ◽  
Newborn Animals

Development of thermoregulation in Spermophilus richardsonii was investigated by determining the ability of neonates to maintain a normal body temperature when exposed to 30 and 25 °C, to maintain an elevated oxygen consumption (cubic centimetre oxygen per gram per hour) at 21 °C compared with that at 35 °C, and to move toward a warm object and assume curling postures when exposed to the cold. Newborn animals were essentially poikilothermic but by day 5 showed strong thermotaxis. By 30 days, the age of emergence from natal burrows, homeothermy had developed to the point at which normal body temperature could be maintained for at least 2 h at an ambient temperature of 25 °C. This process was correlated with improvements in heat production and heat retention. Subsequent growth was marked by a decreased metabolic response to cold (21 °C) owing to decreasing thermal conductance.

STUDIES ON THE ADRENAL AND THYROID GLANDS OF THE GROUND SQUIRREL DURING HIBERNATION

1954 ◽  
Vol 11 (2) ◽  
pp. 125-133 ◽  
Author(s):  
V. L. VIDOVIC ◽  
V. POPOVIC
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Thyroid Gland ◽  
Environmental Conditions ◽  
Ground Squirrel ◽  
Radioactive Iodine ◽  
Ground Squirrels ◽  
Normal Body Temperature ◽  
Thyroid Glands ◽  
Total Adrenalectomy

SUMMARY Hibernation in the ground squirrel ends within 1–2 hr after total adrenalectomy and does not recur. Survival time after adrenalectomy in laboratory-kept ground squirrels during November and December was longer than it was during September-October and February-March. Body temperature during hibernation (4–18° C) was restored to normal (37° C) within 1–2 hr after adrenalectomy, the animals being kept in a room at 17° C. Oxygen consumption was measured in ground squirrels on the 6th and 7th days after adrenalectomy at 31–32° and 4° C respectively. Maximum consumption occurred at 4° C; normal body temperature was retained. The 131I uptake by the thyroid of non-hibernating ground squirrels is considerably smaller in early Autumn (September-October) than during the winter months. Radioactive iodine is not accumulated by the thyroid gland of the hibernating ground squirrel, but 3 days after adrenalectomy the amount of 131I accumulated is equivalent to that taken up by the gland of the non-hibernating animal. The effects of adrenalectomy in the hibernating and non-hibernating ground squirrel are compared with those obtained in hypothermic rats maintained in similar environmental conditions.

Adaptation to cold: energy metabolism in an atypical lagomorph, the arctic hare (Lepus arcticus)

1973 ◽  
Vol 51 (8) ◽  
pp. 841-846 ◽  
Author(s):  
Lawrence C. H. Wang ◽  
Douglas L. Jones ◽  
Robert A. MacArthur ◽  
William A. Fuller
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Thermal Conductance ◽  
Volume Ratio ◽  
The Arctic ◽  
Normal Body Temperature ◽  
Ambient Temperatures ◽  
Normal Body ◽  
Arctic Hare

Unlike other lagomorphs or any other mammals living in a cold environment, the basal metabolic rate of the arctic hare, Lepus arcticus monstrabilis (0.36 cm3 O2/g per hour) was only 62–83% of the values predicted from its body weight. The minimum thermal conductance (0.010 cm3 O2/g per hour per degree centigrade) was also reduced to only 51–59% of its weight-specific value (0.019–0.017 cm3 O2/g per hour per degree centigrade). The normal body temperature (38.9C), however, was comparable to that of other lagomorphs. The daily energy consumption between ambient temperatures of −24 and 12.5C was between 262 and 133 kcal, which is 6–43% above the minimum resting values at corresponding ambient temperatures.It is concluded that the reduction of surface area to volume ratio and the effectiveness of its insulation are sufficient compensations so that the arctic hare can maintain a normal body temperature with a depressed basal metabolic rate. Such a reduction of metabolism is energetically adaptive for a species living exclusively in a cold and relatively barren habitat.

ROLE OF THE ADRENAL CORTEX IN THE ADAPTATION OF THE MONOTREME TACHYGLOSSUS ACULEATUS TO LOW ENVIRONMENTAL TEMPERATURE

1973 ◽  
Vol 58 (3) ◽  
pp. 513-523 ◽  
Author(s):  
M. L. AUGEE ◽  
I. R. McDONALD
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Plasma Glucose ◽  
Prolonged Exposure ◽  
Metabolic Response ◽  
Normal Body Temperature ◽  
Normal Body ◽  
Exposure To Cold ◽  
Blood Glucose Concentrations

SUMMARY When exposed to a low ambient temperature of 5 °C, adrenalectomized echidnas were able to increase their metabolic rate and to maintain their body temperature within the normal range for no more than 48 h — less than 12 h in five out of six animals. Thereafter, activity, metabolic rate, cardiac rate and body temperature declined and the animals became torpid. When maintained with daily i.m. injections of 1–2 mg cortisol acetate/kg, adrenalectomized echidnas maintained activity and normal body temperature in the cold environment indefinitely. When cortisol injections were withheld and exposure to cold continued, normal body temperature was maintained for a further 10 days, after which it declined rapidly. The onset of torpor was always preceded by a marked fall in plasma glucose concentration, as occurred in normal, but fasted, echidnas after prolonged exposure to cold. Both cortisol and corticosterone have glucocorticoid activity in echidnas, and torpor was prevented in adrenalectomized echidnas by preventing the fall in plasma glucose with either intermittent injections or constant rate infusions of glucose solutions. The adrenal glands of normal echidnas exposed repeatedly to low environmental temperatures showed marked hypertrophy and increase in lipid content. It is concluded that adrenocortical secretions are necessary for the metabolic response to cold stress in these prototherian mammals, and a major role of the corticosteroids is in maintenance of normal blood glucose concentrations, presumably by enhancing hepatic gluconeogenesis.

scholarly journals The metabolic response of the Bradypus sloth to temperature

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5600 ◽  
Author(s):  
Rebecca Naomi Cliffe ◽  
David Michael Scantlebury ◽  
Sarah Jane Kennedy ◽  
Judy Avey-Arroyo ◽  
Daniel Mindich ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Energy Expenditure ◽  
High Power ◽  
Metabolic Response ◽  
Metabolic Responses ◽  
Metabolic Depression ◽  
Wide Range ◽  
Energetic Constraints ◽  
Power Costs

Poikilotherms and homeotherms have different, well-defined metabolic responses to ambient temperature (Ta), but both groups have high power costs at high temperatures. Sloths (Bradypus) are critically limited by rates of energy acquisition and it has previously been suggested that their unusual departure from homeothermy mitigates the associated costs. No studies, however, have examined how sloth body temperature and metabolic rate vary with Ta. Here we measured the oxygen consumption (VO2) of eight brown-throated sloths (B. variegatus) at variable Ta’s and found that VO2 indeed varied in an unusual manner with what appeared to be a reversal of the standard homeotherm pattern. Sloth VO2 increased with Ta, peaking in a metabolic plateau (nominal ‘thermally-active zone’ (TAZ)) before decreasing again at higher Ta values. We suggest that this pattern enables sloths to minimise energy expenditure over a wide range of conditions, which is likely to be crucial for survival in an animal that operates under severe energetic constraints. To our knowledge, this is the first evidence of a mammal provisionally invoking metabolic depression in response to increasing Ta’s, without entering into a state of torpor, aestivation or hibernation.

Effects of successive carbon monoxide exposures on delayed neuronal death in mice under the maintenance of normal body temperature

1991 ◽  
Vol 179 (2) ◽  
pp. 836-840 ◽  
Author(s):  
Hirohisa Ishimaru ◽  
Toshitaka Nabeshima ◽  
Akira Katoh ◽  
Hirotaka Suzuki ◽  
Taneo Fukuta ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Body Temperature ◽  
Neuronal Death ◽  
Delayed Neuronal Death ◽  
Normal Body Temperature ◽  
Normal Body

scholarly journals Distribution of Pediatric Vital Signs in the Emergency Department: A Nationwide Study

Children ◽  
2020 ◽  
Vol 7 (8) ◽  
pp. 89
Author(s):  
Woori Bae ◽  
Kyunghoon Kim ◽  
Bongjin Lee
Keyword(s):  
Emergency Department ◽  
Heart Rate ◽  
Body Temperature ◽  
Respiratory Rate ◽  
Life Support ◽  
Vital Signs ◽  
Reference Ranges ◽  
Normal Body Temperature ◽  
Heart Rates ◽  
Normal Body

To effectively use vital signs as indicators in children, the magnitude of deviation from expected vital sign distribution should be determined. The purpose of this study is to derive age-specific centile charts for the heart rate and respiratory rate of the children who visited the emergency department. This study used the Korea’s National Emergency Department Information System dataset. Patients aged <16 years visiting the emergency department between 1 January 2016 and 31 December 2017 were included. Heart rate and respiratory rate centile charts were derived from the population with normal body temperature (36 to <38 °C). Of 1,901,816 data points retrieved from the database, 1,454,372 sets of heart rates and 1,458,791 sets of respiratory rates were used to derive centile charts. Age-specific centile charts and curves of heart rates and respiratory rates showed a decline in heart rate and respiratory rate from birth to early adolescence. There were substantial discrepancies in the reference ranges of Advanced Paediatric Life Support and Pediatric Advanced Life Support guidelines. Age-based heart rate and respiratory rate centile charts at normal body temperature, derived from children visiting emergency departments, serve as new evidence-based data and can be used in follow-up studies to improve clinical care for children.

scholarly journals The Importance of Changes in Body Temperature in Paediatric Surgery and Anaesthesia

1973 ◽  
Vol 1 (6) ◽  
pp. 480-485 ◽  
Author(s):  
Nerida M. Dilworth
Keyword(s):  
Body Temperature ◽  
Newborn Infant ◽  
Paediatric Anaesthesia ◽  
Considerable Importance ◽  
Accidental Hypothermia ◽  
Paediatric Surgery ◽  
Normal Body Temperature ◽  
Normal Body ◽  
The Subject

An understanding of the maintenance of normal body temperature, and the manner in which surgery, anaesthesia, and related procedures may disturb thermoregulation, is of considerable importance in paediatric anaesthesia. The subject of accidental hypothermia, with particular reference to the newborn infant, is reviewed; and hyperpyrexia is briefly discussed.

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.

Sign in / Sign up

Export Citation Format

Share Document