[Changes in the adrenergic regulation of thermogenesis during prolonged rat adaptation to cold].

Comparison of effects of catecholamines (noradrenaline, adrenaline, and isopropyl-noradrenaline) on oxygen consumption and body temperature and study of influence of beta- and alpha-adrenergic blocking agents (poropranolol and phentolamine) on their calorigenic effects in cold- and warm-adapted rats revealed that affinity of propranolol and all the catecholamines to beta-adrenoreceptors is enhanced. Influence of propranolol on the cold thermogenesis involves thermoregulatory metabolism decrease in warm-adapted rats and additional (compensatory) increase of thermoregulatory electrical muscle activity in cold-adapted rats. The sympathetic regulation of heat production and its changes at prolonged cold adaptation seem to be mainly of beta-adrenergic nature.