Effects of noradrenaline and carbachol on temperature regulation of cold-stressed and cold-acclimated rats.
1 Noradrenaline (20 micrograms) and carbachol (1 microgram) injected into the anterior hypothalamus of rats at an ambient temperature of 23 degrees C evoked significant falls in core temperature and increases in tail temperature. 2 When rats were cold-stressed (4 degrees C for 90 min) or cold-acclimated (4 degrees C for 4 weeks) and the above amine injections repeated, only carbachol evoked significant falls in core temperature and neither amine increased tail temperature. 3 Central injections of noradrenaline and carbachol also evoked increases in plasma glucose concentrations but not plasma non-esterified fatty acid (NEFA) concentrations in control, acutely cold-stressed and cold-acclimated rats. 4 Although concentrations of plasma glucose and blood lactate of rats were unaffected by cold exposure to 4 degrees C for 1 to 28 days, glucose oxidation rate of both cold-stressed and cold-acclimated rats was significantly greater than in rats at 23 degrees C. Concentrations of plasma NEFA were increased after 1 to 28 days of cold exposure.
D000064:Acclimatization; D000818:Animals; D001786:Blood Glucose / Q000097:blood; D001831:Body Temperature / Q000187:drug effects; D001833:Body Temperature Regulation / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D002217:Carbachol / Q000494:pharmacology*; D003080:Cold Temperature; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006019:Glycolysis / Q000187:drug effects; D007031:Hypothalamus; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D013312:Stress, Physiological / Q000503:physiopathology*
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D002217:Carbachol; D009638:Norepinephrine