Alpha- and beta-adrenergic receptor blockers and the effects of noradrenaline on heat production and body temperature.

Noradrenaline (NA) administered systemically or into the lateral cerebral ventricle (ICV) in appropriate doses increased heat production and colonic temperature in 1-12 day-old guinea pigs. The effect of systemically applied NA could be blocked by systemically applied beta-adrenergic receptor blockers, while beta-blockers administered centrally or alpha-adrenergic blockers injected systemically or centrally had no effect on the action of systemically applied NA. Accordingly, the effect of systemically applied NA was mediated by peripheral beta-adrenergic receptors. The effect of centrally applied NA was blocked by alpha-adrenergic receptor antagonists applied into the lateral cerebral ventricle and attenuated by systemically applied phentolamine, but not by phenoxybenzamine or ergotamine. Beta-adrenergic receptor blocking agents applied either ICV or systemically had no effect on the action of centrally applied NA. It is concluded that ICV applied NA acts through central alpha-adrenergic receptors.