Effects of long scotophase and cold acclimation on heat production in two diurnal rodents

1982 ◽  
Vol 148 (1) ◽  
pp. 77-81 ◽  
Author(s):  
A. Haim
Keyword(s):  
Cold Acclimation ◽  
Heat Production

THERMOGENESIS DUE TO EXERCISE AND COLD IN WARM- AND COLD-ACCLIMATED RATS

1963 ◽  
Vol 41 (1) ◽  
pp. 629-634 ◽  
Author(s):  
J. S. Hart ◽  
L. Jansky
Keyword(s):  
Cold Acclimation ◽  
Heat Production ◽  
Nonshivering Thermogenesis ◽  
Maximum Heat ◽  
Temperature Range ◽  
Sustained Effort ◽  
Extreme Cold

In both warm- and cold-acclimated rats, heat production was measured while the animals were at rest and running at maximum sustained effort at temperatures from 30 °C to those giving maximum thermogenesis. In both these groups, the maximum heat production during exercise did not exceed the maximum at rest in extreme cold. Exercise substituted for shivering in warm-acclimated rats and, at temperatures below 10 °C, resulted in hypothermia. Heat derived from exercise added to nonshivering thermogenesis in cold-acclimated rats above −20 °C. Below −20 °C, exercise substituted for shivering as in warm-acclimated rats at higher temperatures, and the rats became hypothermic. Extension of the temperature range for activity by cold acclimation appears to result from development of nonshivering thermogenesis, which, unlike shivering, is not eliminated by exercise.

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

Thermoregulation and cold acclimation in a hibernator, Citellus tridecemlincatus

1965 ◽  
Vol 20 (3) ◽  
pp. 398-404 ◽  
Author(s):  
Hermann Pohl ◽  
J. Sanford Hart
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Cold Acclimation ◽  
Heat Production ◽  
Natural Habitat ◽  
Thermal Conductance ◽  
Muscular Activity ◽  
Local Heat ◽  
Ground Squirrels ◽  
Production Body

In the thirteen-lined ground squirrel, Citellus tridecemlineatus, the maintenance of body temperature and oxygen consumption in the cold is improved by acclimation to 18 and 6 C in the laboratory. Heat production at -30 C was greater in animals acclimated to 6 C, whether or not they had been previously hibernating, than in squirrels kept at 28 C. Oxygen consumption was correlated to body weight0.41. This relationship was not significantly affected by changes in ambient temperature. Local heat flow from the dorsal thorax was similar at a given temperature in all acclimation groups but the thermal conductance was greater and the cardiac-subcutaneous temperature difference was smaller in squirrels acclimated to 6 and 18 C. Although shivering was equally high in warm- and cold-acclimated ground squirrels in the cold, nonshivering thermogenesis occurred in curarized cold-acclimated animals exposed to cold or injected with noradrenaline. The results of the study suggest that ground squirrels are regularly exposed to temperatures in their natural habitat which induce considerable cold acclimation. oxygen consumption—heat production; body temperature—heat conductance; muscular activity Submitted on July 6, 1964

scholarly journals Cold Tolerance in Hypothyroid Rabbits: Role of Skeletal Muscle Mitochondria and Sarcoplasmic Reticulum Ca2+ ATPase Isoform 1 Heat Production

Endocrinology ◽  
2008 ◽  
Vol 149 (12) ◽  
pp. 6262-6271 ◽  
Author(s):  
Ana Paula Arruda ◽  
Luisa A. Ketzer ◽  
Mariana Nigro ◽  
Antonio Galina ◽  
Denise P. Carvalho ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Cold Acclimation ◽  
Cold Tolerance ◽  
Heat Production ◽  
Cold Exposure ◽  
Muscle Enzymes ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Brown Adipose

Brown adipose tissue (BAT) is involved in rat and mice thermoregulation, and heat produced by BAT depends on the concerted action of thyroid hormones and catecholamines. Little is known about cold-induced thermogenesis in mammals that have little or no BAT, such as rabbits. In these animals, thermogenesis primarily occurs in skeletal muscle. In this work, we have studied the effect of cold acclimation (4 C for 10 d) in normal and hypothyroid rabbits. It is known that hypothyroid rats die after a few hours of cold exposure. We now show that, different from rats, hypothyroid rabbits sustain their body temperature and survive after 10 d cold exposure. When compared with rabbits kept at room temperature, the muscles of cold-exposed rabbits showed a dark red color characteristic of oxidative muscle fibers. According to this pattern, we observed that in both normal and hypothyroid rabbits, cold exposure promotes an increase in oxygen consumption by skeletal muscle mitochondria. Moreover, in red muscle, cold acclimation induces an increase in the expression and activity of sarcoplasmic reticulum Ca2+ ATPase isoform 1 (SERCA1), one of the muscle enzymes involved in heat production. We conclude that rabbit cold tolerance is probably related to increased muscle oxidative metabolism and heat production by SERCA1 and that these changes are not completely dependent on normal thyroid function.

Parallel measurements of heat production and thermogenin content in brown fat cells during cold acclimation of rats

1986 ◽  
Vol 6 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Erik Steen Hansen ◽  
Jens Knudsen
Keyword(s):  
Cold Acclimation ◽  
Heat Production ◽  
Continuous Flow ◽  
Specific Protein ◽  
Competitive Elisa ◽  
Brown Fat ◽  
Fat Cells ◽  
Two Parameters ◽  
Parallel Measurements ◽  
Thermogenic Capacity

The maximum thermogenic capacity of brown fat cells from control and cold acclimated rats was measured using a continuous-flow microcalorimetric system, The content of the 32.000 D, brown fat specific protein, thermogenin, was measured in the cells used for heat production measurements by competitive ELISA. The ratio between the maximal thermogenic capacity and the amount ofthermogenin for control and cold acclimated rats was compared. It was found that the ratio between the two parameters decreased during cold acclimation due to a decrease in maximal thermogenic capacity and an increase in the amount ofthermogenin, indicating regulation of heat production either at thermogenin or receptor level.

scholarly journals Seven days of cold acclimation substantially reduces shivering intensity and increases nonshivering thermogenesis in adult humans

2019 ◽  
Vol 126 (6) ◽  
pp. 1598-1606 ◽  
Author(s):  
Kyle Gordon ◽  
Denis P. Blondin ◽  
Brian J. Friesen ◽  
Hans Christian Tingelstad ◽  
Glen P. Kenny ◽  
...  
Keyword(s):  
Cold Acclimation ◽  
Core Temperature ◽  
Heat Production ◽  
Cold Exposure ◽  
Cold Water ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Metabolic Changes ◽  
Whole Body ◽  
Nonshivering Thermogenesis

Daily compensable cold exposure in humans reduces shivering by ~20% without changing total heat production, partly by increasing brown adipose tissue thermogenic capacity and activity. Although acclimation and acclimatization studies have long suggested that daily reductions in core temperature are essential to elicit significant metabolic changes in response to repeated cold exposure, this has never directly been demonstrated. The aim of the present study is to determine whether daily cold-water immersion, resulting in a significant fall in core temperature, can further reduce shivering intensity during mild acute cold exposure. Seven men underwent 1 h of daily cold-water immersion (14°C) for seven consecutive days. Immediately before and following the acclimation protocol, participants underwent a mild cold exposure using a novel skin temperature clamping cold exposure protocol to elicit the same thermogenic rate between trials. Metabolic heat production, shivering intensity, muscle recruitment pattern, and thermal sensation were measured throughout these experimental sessions. Uncompensable cold acclimation reduced total shivering intensity by 36% ( P = 0.003), without affecting whole body heat production, double what was previously shown from a 4-wk mild acclimation. This implies that nonshivering thermogenesis increased to supplement the reduction in the thermogenic contribution of shivering. As fuel selection did not change following the 7-day cold acclimation, we suggest that the nonshivering mechanism recruited must rely on a similar fuel mixture to produce this heat. The more significant reductions in shivering intensity compared with a longer mild cold acclimation suggest important differential metabolic responses, resulting from an uncompensable compared with compensable cold acclimation. NEW & NOTEWORTHY Several decades of research have been dedicated to reducing the presence of shivering during cold exposure. The present study aims to determine whether as little as seven consecutive days of cold-water immersion is sufficient to reduce shivering and increase nonshivering thermogenesis. We provide evidence that whole body nonshivering thermogenesis can be increased to offset a reduction in shivering activity to maintain endogenous heat production. This demonstrates that short, but intense cold stimulation can elicit rapid metabolic changes in humans, thereby improving our comfort and ability to perform various motor tasks in the cold. Further research is required to determine the nonshivering processes that are upregulated within this short time period.

THERMOGENESIS DUE TO EXERCISE AND COLD IN WARM- AND COLD-ACCLIMATED RATS

1963 ◽  
Vol 41 (3) ◽  
pp. 629-634 ◽  
Author(s):  
J. S. Hart ◽  
L. Jansky
Keyword(s):  
Cold Acclimation ◽  
Heat Production ◽  
Nonshivering Thermogenesis ◽  
Maximum Heat ◽  
Temperature Range ◽  
Sustained Effort ◽  
Extreme Cold

In both warm- and cold-acclimated rats, heat production was measured while the animals were at rest and running at maximum sustained effort at temperatures from 30 °C to those giving maximum thermogenesis. In both these groups, the maximum heat production during exercise did not exceed the maximum at rest in extreme cold. Exercise substituted for shivering in warm-acclimated rats and, at temperatures below 10 °C, resulted in hypothermia. Heat derived from exercise added to nonshivering thermogenesis in cold-acclimated rats above −20 °C. Below −20 °C, exercise substituted for shivering as in warm-acclimated rats at higher temperatures, and the rats became hypothermic. Extension of the temperature range for activity by cold acclimation appears to result from development of nonshivering thermogenesis, which, unlike shivering, is not eliminated by exercise.

Catecholamines and cold thermogenesis in sheep

1969 ◽  
Vol 47 (8) ◽  
pp. 719-724 ◽  
Author(s):  
A. J. F. Webster ◽  
J. H. Heitman ◽  
F. L. Hays ◽  
G. P. Olynyk
Keyword(s):  
Urinary Excretion ◽  
Cold Stress ◽  
Cold Acclimation ◽  
Heat Production ◽  
Adult Sheep ◽  
Noradrenaline And Adrenaline

Experiments were performed to assess the role of catecholamines in cold thermogenesis in warm- and cold-acclimated adult sheep. Urinary excretion of both noradrenaline and adrenaline increased in sheep exposed to cold. Propranolol (1 mg/kg) reduced cold thermogenesis in warm- and cold-acclimated sheep by 8% and 12% respectively. Noradrenaline and adrenaline infusions at 1 μg/kg min for 30 min had no significant effect on the rate of heat production of warm- or cold-acclimated sheep. Phenoxybenzamine (3.0 mg/kg) almost abolished cold thermogenesis in warm-acclimated sheep. Cold-acclimated animals treated with phenoxybenzamine were able to maintain homeothermy during severe cold stress. These findings support previous reports which suggest that catecholamines are involved in metabolic cold acclimation in the sheep, but indicate clearly that they have no direct thermogenic effect in cold-acclimated adults of this species.

scholarly journals The relationship of muscle electrical activity, tremor and heat production to shivering thermogenesis in Japanese quail

1986 ◽  
Vol 125 (1) ◽  
pp. 119-135 ◽  
Author(s):  
E. Hohtola ◽  
E. D. Stevens
Keyword(s):  
Electrical Activity ◽  
Cold Acclimation ◽  
Japanese Quail ◽  
Heat Production ◽  
Neural Control ◽  
Power Spectra ◽  
Amplitude Distribution ◽  
Pectoral Muscle ◽  
Temperature Acclimation ◽  
Emg Activity

We measured the electrical activity and the tremor of the pectoral muscle and total body heat production in control and cold-acclimated Japanese quail at +26 degrees C, +12 degrees C and +2 degrees C before and after 3 weeks of acclimation, using electromyography, accelerometer recordings, and indirect calorimetry. Japanese quail shiver in 0.2- to 3-s bursts that occur in groups. An increase in both the frequency and the duration of bursts and burst groups contributes to the increase in heat production by shivering at low temperatures. A compilation of shivering patterns in birds is given and its implications for the neural control and phylogeny of shivering are discussed. A rather non-specific increase in electromyographic (EMG) activity and heat production was observed after cold acclimation at all experimental temperatures, although many of the normal signs of cold acclimation (e.g. decrease in gonad mass, increase in heart mass and serum triiodothyronine) were seen. The increase in muscle electrical activity was greater than the increase in oxygen uptake, which resulted in a lower VO2/EMG ratio. The amplitude distribution of muscle electrical activity remained normal, but a shift towards higher frequencies occurred in the EMG spectra of cold-acclimated birds. Despite the increase in muscle electrical activity, power spectra of accelerometer recordings indicated that the amplitude of the muscle tremor was lower in cold-acclimated birds. The increase in the high-frequency components of the EMG indicates that decreased synchronization of motor unit firing may account for the lower tremor amplitude. We suggest that this change is adaptive because it reduces heat loss and/or because more fatigue-resistant motor units are recruited. These results show that temperature acclimation modifies the neural control of shivering in skeletal muscle.

Marker Trait Association for Autumn Cold Acclimation and Growth Rhythm in Pinus sylvestris

2003 ◽  
Vol 18 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Reza Yazdani ◽  
Jan-erik Nilsson ◽  
Christophe Plomion ◽  
Gaurov Mathur
Keyword(s):  
Pinus Sylvestris ◽  
Cold Acclimation ◽  
Growth Rhythm ◽  
Trait Association
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