The importance of the adrenergic beta-receptors for thermogenesis and survival of acutely cold-exposed mice

1969 ◽  
Vol 47 (5) ◽  
pp. 427-434 ◽  
Author(s):  
C.-J. Estler ◽  
H. P. T. Ammon
Keyword(s):  
Survival Rate ◽  
Heat Production ◽  
Cold Exposure ◽  
Blocking Agent ◽  
Special Importance ◽  
Receptor Blocking ◽  
Acute Cold Exposure ◽  
Adrenal System ◽  
Beta Receptors ◽  
Β Receptor

In normal warm-adapted mice a lowering of the ambient temperature to 0 °C was followed by piloerection, shivering, and an increase of oxygen consumption, which prevented a serious hypothermia. The survival rate after 4 h cold exposure was 82%. Mice pretreated with a β-receptor blocking agent, propranolol, MJ 1999, or INPEA, showed piloerection and shivering when exposed to 0 °C, but their ability to increase heat production was impaired. Depending upon the dose of the β-receptor blocking agent used, the increase in the metabolic rate was diminished, and rectal temperature and survival rate dropped sharply. After 25 μg/g MJ 1999, only 13% of the animals survived. After 20 μg/g propranolol or 100 μg/g INPEA all animals died. The results give evidence for the importance of the sympatho–adrenal system in general for the maintenance of body temperature and the survival after acute cold exposure, and for the special importance of the adrenergic β-receptors, which are necessary for the animals to increase their heat production.

Effects of beta-adrenergic blockade on the heart rate and energy expenditure of sheep during feeding and during acute cold exposure

1968 ◽  
Vol 46 (4) ◽  
pp. 577-583 ◽  
Author(s):  
A. J. F. Webster ◽  
F. L. Hays
Keyword(s):  
Heart Rate ◽  
Energy Expenditure ◽  
Cold Exposure ◽  
Blocking Agent ◽  
Minor Importance ◽  
Adrenergic Blockade ◽  
Beta Adrenergic ◽  
Cardiac Responses ◽  
Acute Cold Exposure ◽  
Series Of Experiments

Heart rates, respiratory exchange, and rectal temperatures of five sheep were measured during 4 h exposure to −30 °C and during a 3-h period at +8 °C in which the sheep fed for 1 h. Propranolol, a beta-adrenergic receptor blocking agent, was infused at 0.25, 0.5, and 1.0 mg/kg in both series of experiments. These doses blocked isoproterenol-induced tachycardia. Exposure of the untreated sheep to −30 °C produced marked increases in both energy expenditure and heart rate. Propranolol infusion at 0.25 and 0.5 mg/kg had no effect on energy expenditure but almost totally abolished cardioacceleration in response to cold. Propranolol at 1.0 mg/kg significantly reduced energy expenditure at −30 °C. Both heart rate and energy expenditure increased markedly in the untreated sheep during feeding. Propranolol at 0.25, 0.5, and 1.0 mg/kg had significantly similar effects on heart rate during feeding, reducing the absolute values attained at only 12%. Cardioacceleration during feeding was, however, reduced by 46% because propranolol infusion increased heart rate in the prefeeding period. Propranolol at 0.5 mg/kg had no effect on energy expenditure during feeding. It was concluded that the sympathetic system, acting through the beta receptors, is of major importance in controlling the metabolic and cardiac responses of sheep to acute cold exposure, but of minor importance in initiating and regulating these responses during feeding.

SEASONAL CHANGES IN THE PHYSIOLOGICAL RESPONSE OF MAN TO AN ACUTE COLD STRESS

1967 ◽  
Vol 45 (1) ◽  
pp. 13-27 ◽  
Author(s):  
F. Girling
Keyword(s):  
Cold Stress ◽  
Heat Production ◽  
Cold Exposure ◽  
Seasonal Changes ◽  
Human Subjects ◽  
Minute Ventilation ◽  
Acute Cold Exposure ◽  
Air Temperatures ◽  
The Individual ◽  
Shivering Thermogenesis

Eight male human subjects, resting supine, and wearing swim trunks only, were exposed to an ambient temperature of 8.5 °C for 1 hour in the first week of each month from February 1964 to January 1965 inclusive. Skin, rectal, and air temperatures were measured with thermistor probes. Percentage oxygen in expired air and minute ventilation were measured, and heat production was calculated by Weir's method. Electrical activity from the muscles of all four limbs was measured to determine shivering response. Control values of resting respiration and heat production were obtained under comfortably warm conditions and showed marked seasonal variation, with minimum values in spring and maximum values in later summer. In the response to acute cold exposure, marked seasonal changes were found also which were superimposed on the seasonal changes in control values. The response to cold exposure indicated maximum acclimatization to cold in the spring and minimum in later summer. These results are discussed in terms of three modes of response to the cold stress: (i) insulative cooling, (ii) shivering thermogenesis, and (iii) nonshivering thermogenesis. The degree of acclimatization and temperature of exposure may determine the individual mode of response.

scholarly journals Hemodynamic Effects of an Adrenergic β-Receptor Blocking Agent, Kö1366 in Old Subjects

1977 ◽  
Vol 8 (4) ◽  
pp. 471-484
Author(s):  
Fujio TERASAWA ◽  
Masao IKEDA ◽  
Takaomi SUZUKI ◽  
Hon Ying LIE ◽  
Masuji SEKI
Keyword(s):  
Blocking Agent ◽  
Hemodynamic Effects ◽  
Receptor Blocking ◽  
Β Receptor
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