Effects of lysine-vasopressin and oxytocin on central cardiovascular control.
1 The cardiovascular effects of intravenous and intracisternal administration of neurohypophysial peptides were compared in dogs anaesthetized with chloralose. 2 Intravenous lysine-vasopressin (0.1 to 100 mu/kg) induced a dose-dependent increase in blood pressure and a decrease in heart rate. In contrast, intracisternal lysine-vasopressin (0.01 to 10 mu/kg induced a dose-related decrease in blood pressure and did not change heart rate. 3 Intracisternal oxytocin (1 and 10 mu/kg) increased blood pressure and did not change heart rate, whereas the same doses injected intravenously were inactive. 4 Pretreatment with guanethidine (15 mg/kg i.v. 24 h beforehand) abolished the hypotensive responses to intracisternal vasopressin but not the pressor action of intravenous vasopressin. 5 The pressor responses to central injections of oxytocin were not modified by guanethidine. 6 Hypotension elicited by intracisternal vasopressin was probably due to a decrease in sympathetic tone whereas the hypertension induced by intracisternal oxytocin was independent of variations in sympathetic tone.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002946:Cisterna Magna; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D006145:Guanethidine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007267:Injections; D008236:Lypressin / Q000494:pharmacology*; D008297:Male; D010121:Oxytocin / Q000494:pharmacology*
D010121:Oxytocin; D008236:Lypressin; D006145:Guanethidine