Contribution of shivering in leg muscles to heat production in Japanese quail

1986 ◽  
Vol 64 (4) ◽  
pp. 889-892 ◽  
Author(s):  
E. Don Stevens ◽  
J. Ferguson ◽  
V. G. Thomas ◽  
E. Hohtola
Keyword(s):  
Ambient Temperature ◽  
Japanese Quail ◽  
Heat Production ◽  
Open Circuit ◽  
Linear Rate ◽  
Ambient Temperatures ◽  
Coturnix Coturnix ◽  
Metabolic Heat ◽  
Leg Muscles ◽  
Flight Muscles

We estimated heat production in Japanese quail (Coturnix coturnix japonica) by measuring oxygen uptake using open-circuit respirometry as ambient temperature was decreased gradually from 26 to 3.5 °C. At the same time, the intensity of shivering was estimated in both the leg muscles and the flight muscles by measuring electromyograms. Metabolic heat production increased in a linear fashion as ambient temperature decreased. Shivering intensity increased at the same linear rate in the leg muscles as in the flight muscles as ambient temperature decreased. The leg muscles produce a substantial fraction (about 1/4) of the total shivering heat production at low ambient temperatures. Shivering occurred in bursts; the onset of a burst in the leg muscles was precisely synchronized with the onset of a burst in the flight muscles.

Activation of the Fibrillar Muscles in the Bumblebee During Warm-Up, Stabilization of Thoracic Temperature and Flight

1973 ◽  
Vol 58 (3) ◽  
pp. 677-688
Author(s):  
BERND HEINRICH ◽  
ANN E. KAMMER
Keyword(s):  
Heat Production ◽  
Action Potentials ◽  
Spike Frequency ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Heating And Cooling ◽  
Thoracic Temperature ◽  
Flight Muscles ◽  
Frequency Of Action Potentials ◽  
Physical Laws

1. Extracellular action potentials and thoracic temperatures (TTh) were simultaneously recorded from the fibrillar flight muscles of Bombus vosnesenskii queens during preflight warm-up, during stabilization of TTh in stationary bees, and during fixed flight. 2. In most stationary bees during warm-up and during the stabilization of TTh the rate of heat production, as calculated from thoracic temperature and passive rates of cooling, is directly related to the frequency of action potentials in the muscles. 3. The rate of heat production increases throughout warm-up primarily because of a greater spike frequency at higher TTh. 4. In stationary bees during the stabilization of TTh at different ambient temperatures (TA) the fibrillar muscles are activated by any in a continuous range of spike frequencies, rather than only by on-off responses. 5. Regulation of TTh in stationary bees may involve not only changes in the rate of heat production but also variations of heat transfer from the thorax to the abdomen. 6. During fixed flight the fibrillar muscles are usually activated at greater rates at the initiation of flight than later in flight, but the spike frequency and thus heat production are not varied in response to differences in TA and heating and cooling rates. 7. During fixed flight TTh is not regulated at specific set-points; TTh appears to vary passively in accordance with the physical laws of heating and cooling. 8. Differences in the TTh of bees in free and in fixed flight are discussed with regard to mechanisms of thermoregulation.

Poly I:C-induced fever elevates threshold for shivering but reduces thermosensitivity in rabbits

1995 ◽  
Vol 268 (5) ◽  
pp. R1266-R1272 ◽  
Author(s):  
O. Toien ◽  
J. B. Mercer
Keyword(s):  
Heat Exchanger ◽  
Ambient Temperature ◽  
Heat Production ◽  
Metabolic Heat Production ◽  
Poly I:C ◽  
Saline Injection ◽  
Hypothalamic Temperature ◽  
Square Wave ◽  
Metabolic Heat ◽  
Fever Response

Shivering threshold and thermosensitivity were determined in six conscious rabbits at ambient temperature (Ta) 20 and 10 degrees C before and at six different times after saline injection (0.15 ml iv) and polyriboinosinic-polyribocytidylic acid (poly I:C)-induced fever (5 micrograms/kg iv). Thermosensitivity was calculated by regression of metabolic heat production (M) and hypothalamic temperature (Thypo) during short periods (5-10 min) of square-wave cooling. Heat was extracted with a chronically implanted intravascular heat exchanger. Shivering threshold was calculated as the Thypo at which the thermosensitivity line crossed resting M as measured in afebrile animals at Ta 20 degrees C. There were negligible changes in shivering threshold and thermosensitivity in saline-injected rabbits. In the febrile animals, shivering threshold generally followed the shape of the biphasic fever response. At Ta 20 degrees C, shivering threshold was higher than regulated Thypo during the initial rising phase of fever and was lower during recovery. At Ta 10 degrees C the shivering thresholds were always higher than regulated Thypo except during recovery. Thermosensitivity was reduced by 30-41% during fever.

Effects of altered ambient temperature on metabolic rate during CO2 inhalation

1985 ◽  
Vol 58 (5) ◽  
pp. 1592-1596 ◽  
Author(s):  
R. P. Kaminski ◽  
H. V. Forster ◽  
G. E. Bisgard ◽  
L. G. Pan ◽  
S. M. Dorsey ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Heat Production ◽  
Pulmonary Ventilation ◽  
O2 Consumption ◽  
Breathing Frequency ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Respiratory Heat Loss ◽  
Unit Increase ◽  
Stimulation Of

The purpose of this study was to determine if the changes in O2 consumption (VO2) during CO2 inhalation could in part be due to stimulation of thermogenesis for homeothermy. Twelve ponies were exposed for 30-min periods to inspired CO2 (PIco2) levels of less than 0.7, 14, 28, and 42 Torr during the winter at 5 (neutral) and 23 degrees C ambient temperatures (TA) and during the summer at 21 (neutral TA), 30, and 12 degrees C. Elevating TA in both seasons resulted in an increased pulmonary ventilation (VE) and breathing frequency (f) (P less than 0.01) but no significant increase in VO2 (P greater than 0.05). Decreasing TA in the summer resulted in a decrease in VE and f (P less than 0.01) but no significant change in VO2 (P greater than 0.05). At neutral TA in both seasons, VO2 increased progressively (P less than 0.05) as PIco2 was increased from 14 to 28 and 42 Torr. The increases in VO2 during CO2 inhalation were attenuated (P less than 0.05) at elevated TA and accentuated at the relatively cold TA in the summer (P less than 0.05). Respiratory heat loss (RHL) during CO2 inhalation was inversely related to TA. Above a threshold RHL of 2 cal X min-1 X m-2, metabolic heat production (MHP) increased 0.3 cal X min-1 X m-2 for each unit increase in RHL during CO2 inhalation at the neutral and elevated TA. However, during cold stress in the summer, the slope of the MHP-RHL relationship was 1.6, indicating an increased MHP response to RHL.

Energy utilization in the laying hen in relation to ambient temperature

1973 ◽  
Vol 81 (1) ◽  
pp. 173-177 ◽  
Author(s):  
R. H. Davis ◽  
O. E. M. Hassan ◽  
A. H. Sykes
Keyword(s):  
Ambient Temperature ◽  
Energy Intake ◽  
Heat Production ◽  
Egg Production ◽  
Energy Utilization ◽  
Ambient Temperatures ◽  
Thermoneutral Zone ◽  
Energy Retention ◽  
The Difference ◽  
Energy Balances

SummaryEnergy balances have been determined, using the comparative slaughter procedure, over 3-week periods on groups of laying hens kept at ambient temperatures of 7·2, 15·6, 23·9, 29·4 and 35 °C.Energy intake declined as the environment became warmer (kcal ME/kg¾/day = 203· 1·13°C); heat production, as measured by the difference between energy intake and energy retention, also declined with increasing ambient temperature (kcal/kg¾/day = 151 – 1·11°C). There was a linear relationship between heat production and ambient temperature with no thermoneutral zone or critical temperature.The energy available for egg production remained almost constant at 50 kcal/kg¾/day equivalent to a rate of egg production of 82% at each ambient temperature.

Responses of young calves to low ambient temperatures at two levels of feeding

1992 ◽  
Vol 55 (3) ◽  
pp. 397-405 ◽  
Author(s):  
J. W. Schrama ◽  
A. Arieli ◽  
M. J. W. Heetkamp ◽  
M. W. A. Verstegen
Keyword(s):  
Energy Metabolism ◽  
Ambient Temperature ◽  
Rectal Temperature ◽  
Heat Production ◽  
Experimental Period ◽  
Metabolizable Energy ◽  
Ambient Temperatures ◽  
Feeding Level ◽  
Holstein Friesian ◽  
Maintenance Requirements

AbstractSeven groups of five or six Holstein-Friesian male calves were transported to an experimental farm at 2 to 3 days of age. At 6 days of age, heat production (HP) and metabolizable energy (ME) intake were measured for an 8-day period. During this period, calves were exposed to various ambient temperatures: 6, 9, 12 and 15°C. Ambient temperature was constant within days, but changed between days. Calves were fed below (four groups) or near (three groups) the maintenance requirements (290 or 460 kJ ME per kg M0·75 per day).From 6 to 14 days of age the lower critical temperature (Tc) was 12·5°C and HP increased by 8·4 kJ/kg M0·75 per day per °Cfall in ambient temperature below Tc. Both Tc and increase in HP below Tc were not affected by feeding level. Rectal temperature was lower at low ambient temperatures. The decrease in rectal temperature with ambient temperature was greatest at the low feeding level.During the experimental period, calves were not in a steady-state regarding energy metabolism. Heat production decreased with time. This decrease was affected by feeding level and ambient temperature. After arrival, the influence of both ambient temperature and feeding level on the energy metabolism of young calves increased with time.

Effects of phentolamine on thermoregulatory functions of rats to different ambient temperatures

1979 ◽  
Vol 57 (12) ◽  
pp. 1401-1406 ◽  
Author(s):  
M. T. Lin ◽  
Andi Chandra ◽  
T. C. Fung
Keyword(s):  
Heat Loss ◽  
Rectal Temperature ◽  
Heat Production ◽  
Room Temperature ◽  
Metabolic Heat Production ◽  
Central Component ◽  
Evaporative Heat Loss ◽  
Central Administration ◽  
Ambient Temperatures ◽  
Metabolic Heat

The effects of both systemic and central administration of phentolamine on the thermoregulatory functions of conscious rats to various ambient temperatures were assessed. Injection of phentolamine intraperitoneally or into a lateral cerebral ventricle both produced a dose-dependent fall in rectal temperature at room temperature and below it. At a cold environmental temperature (8 °C) the hypothermia in response to phentolamine was due to a decrease in metabolic heat production, but at room temperature (22 °C) the hypothermia was due to cutaneous vasodilatation (as indicated by an increase in foot and tail skin temperatures) and decreased metabolic heat production. There were no changes in respiratory evaporative heat loss. However, in the hot environment (30 °C), phentolamine administration produced no changes in rectal temperature or other thermoregulatory responses. A central component of action is indicated by the fact that a much smaller intraventricular dose of phentolamine was required to exert the same effect as intraperitoneal injection. The data indicate that phentolamine decreases heat production and (or) increases heat loss which leads to hypothermia, probably via central nervous system actions.

Hypoxia similarly impairs metabolic responses to cutaneous and core cold stimuli in conscious rats

1994 ◽  
Vol 77 (2) ◽  
pp. 726-730 ◽  
Author(s):  
G. G. Giesbrecht ◽  
J. E. Fewell ◽  
D. Megirian ◽  
R. Brant ◽  
J. E. Remmers
Keyword(s):  
Ambient Temperature ◽  
Core Temperature ◽  
Heat Production ◽  
Metabolic Response ◽  
Metabolic Heat Production ◽  
Conscious Rats ◽  
Metabolic Heat ◽  
Thermoregulatory Responses ◽  
Body Core ◽  
Core Cooling

Cold exposure elicits several thermoregulatory responses, including an increased metabolic heat production from shivering and nonshivering thermogenesis. The increased metabolism can be in response to body core and/or body cutaneous cooling. Hypoxic hypoxia has been shown to attenuate the metabolic response to cutaneous cooling. We measured metabolic heat production in adult conscious rats during independent cutaneous and core cooling, during normoxia and hypoxia, to 1) test the hypothesis that hypoxia suppresses the metabolic response to independent core cooling and 2) determine whether hypoxia acts preferentially on the response to cutaneous or core cooling. The animals were studied in a temperature-controlled metabolic chamber, and body core temperature was controlled by an abdominal heat exchange coil. Ambient temperature was varied (10, 19, and 28 degrees C) while core temperature was clamped at 37 degrees C or core temperature was varied (33, 35, and 37 degrees C) at a stable ambient temperature of 28 degrees C. Our data indicate that although the sensitivity of the metabolic response to core cooling is about five to six times that to cutaneous cooling. Hypoxia similarly attenuates thermoregulatory responses to both stimuli.

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

An Analysis of Pre-Flight Warm-Up in the Sphinx Moth, Manduca Sexta

1971 ◽  
Vol 55 (1) ◽  
pp. 223-239 ◽  
Author(s):  
BERND HEINRICH ◽  
GEORGE A. BARTHOLOMEW
Keyword(s):  
Ambient Temperature ◽  
Manduca Sexta ◽  
Heat Production ◽  
Blood Circulation ◽  
Cardiac Activity ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature ◽  
Wing Vibration ◽  
Rate Of Increase

The physiology of pre-flight warm-up in Manduca sexta was analysed with regard to rate of heat production, regional partitioning of heat between thorax and abdomen, and the control of blood circulation. 1. When moths which have come to equilibrium with ambient temperature undergo pre-flight warm-up, the thoracic temperature increases linearly until flight temperature (37-39 °C) is approached. 2. The rate of increase in thoracic temperature during warm-up increases directly with ambient temperature from about 2 °C/min at 15 °C to about 7.6 °C/min at 30 °C. 3. The temperature of the abdomen remains near ambient throughout the period of warm-up, but during the initial part of post-flight cooling while thoracic temperature declines sharply abdominal temperatures rise appreciably. 4. During warm-up the rate of wing vibration increases linearly with thoracic temperature. At a thoracic temperature of 15 °C the rate is about 8/sec and at 35 °C it is about 25/sec. 5. When resting animals are held by the legs they at once begin to beat their wings through a wide angle. These wing beats at any given thoracic temperature are slower than the wing vibrations characteristic of normal warm-up, but they cause thoracic temperature to increase at almost the normal rate. 6. The removal of thoracic scales causes a decrease in rate of warm-up, but in still air this does not prevent the moths from reaching flight temperature. 7. During cooling the rate of decrease in thoracic temperature is greater in live animals than in freshly killed ones. At any given difference between thoracic and ambient temperatures cooling rates are directly related to thoracic temperature. 8. In resting moths heart pulsations are usually variable with regard to rate, amplitude, rhythm, and sometimes direction, but the records of cardiac activity simultaneously obtained from thorax and abdomen show close correspondence. 9. During warm-up the records of changes in impedance from electrodes in the abdomen indicate that pulsations of the abdominal heart are either absent, greatly reduced, or at a frequency different from that simultaneously recorded from the thorax. 10. The calculated rate of heat production during warm-up is linearly related to thoracic temperature. 11. Our data are consistent with the assumption that heat produced in the thorax during warm-up is sequestered there by reduction in blood circulation between thorax and abdomen. 12. Rates of warm-up in insects are close to the values predicted on the basis of body weight from data on heterothermic birds and animals.

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