Temperature-dependent effects of ephedrine in the cold.
This experiment examined the effects of intraperitoneal ephedrine (5-25 mg/kg) on operant thermoregulatory behavior of rats in the cold (-8 degrees C), and of 10 mg/kg on metabolic rate at a thermoneutral (22 degrees C) ambient temperature (Ta) and in the cold (5 degrees C). Posttest colonic temperature (Tc) decreased dose-dependently in the behavioral tests, yet the demand for heat varied little with respect to saline except for a significant reduction at the lowest dose tested (i.e., there was no compensation for the reduced Tc induced by ephedrine). Ephedrine had a potent thermogenic effect at a Ta of 22 degrees C, increasing both metabolic rate and Tc. In the cold, ephedrine reduced Tc, but this effect could not be accounted for by a reduction in metabolism, which was not significantly different from saline.
Carlisle
H J
HJ
Department of Psychology, University of California, Santa Barbara 93106, USA.
Stock
M J
MJ
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D001833:Body Temperature Regulation / Q000187:drug effects*; D003080:Cold Temperature; D004305:Dose-Response Relationship, Drug; D004809:Ephedrine / Q000494:pharmacology*; D005260:Female; D051381:Rats; D017207:Rats, Sprague-Dawley
D004809:Ephedrine