Possible involvement of beta 2-adrenoceptors in hyperthermic effect of l-ephedrine in rats.

The experiments were conducted in order to examine the mechanism of hyperthermia induced by l-ephedrine in rats. beta-Adrenoceptor agonists have been known to enhance normal body temperature. Therefore, the effect of various beta-adrenoceptor agonists on body temperature in rats was examined to clarify the mechanism of action of l-ephedrine. The results showed that drugs with beta 2-adrenoceptor agonist activity and l-ephedrine caused hyperthermia in rats and this effect was selectively inhibited by pretreatment of animals with propranolol (a mixed beta-adrenoceptor antagonist) or butoxamine (a selective beta 2-adrenoceptor antagonist). These results suggest that hyperthermic action of l-ephedrine may largely be due to its effect on beta-adrenoceptors.