Increases in plasma cyclic AMP dependent on endogenous catecholamines.
Administration of tyramine (with or without phentolamine) as well as induction of ether anesthesia or insulin hypoglycemia caused a sharp increase in plasma cyclic AMP in rats. Based on the findings that the treatment of rats with reserpine, 6-hydroxydopamine, cocaine or propranolol totally abolished tyramine-induced increases in plasma cyclic AMP, it was concluded that catecholamines released from sympathetic neuronal terminals by tyramine could activate adenylate cyclase via the stimulation of postsynaptic beta-adrenoceptors. In contrast, catecholamines secreted from adrenal medulla were largely responsible for the increase in plasma cyclic AMP induced by ether anesthesia; whereas glucagon, in addition to adrenal catecholamines, played a significant role in hypoglycemia-induced increases in plasma cyclic AMP. Assay of plasma cyclic AMP following these stimuli is very promising as a test for adrenergic activities in experimental and clinical studies.
D000818:Animals; D002395:Catecholamines / Q000502:physiology*; D003042:Cocaine / Q000494:pharmacology; D000242:Cyclic AMP / Q000097:blood*; D004986:Ether / Q000494:pharmacology; D006892:Hydroxydopamines / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D008297:Male; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D012110:Reserpine / Q000494:pharmacology; D013618:Tachyphylaxis; D013997:Time Factors; D014439:Tyramine / Q000494:pharmacology
D002395:Catecholamines; D006892:Hydroxydopamines; D007328:Insulin; D004986:Ether; D012110:Reserpine; D011433:Propranolol; D000242:Cyclic AMP; D003042:Cocaine; D014439:Tyramine; D010646:Phentolamine