title: Centrally induced hypotension and bradycardia after administration of alpha-methylnoradrenaline into the area of the nucleus tractus solitarii of the rat.
abstract: 1 In anaesthetized rats, bilateral injections of alpha-methylnoradrenaline, noradrenaline or adrenaline into the area of the nucleus tractus solitarii (NTS) of the brain stem caused dose-dependent decreases of systemic arterial blood pressure and heart rate. The effects of alpha-methylnoradrenaline were most pronounced and lasted longest. 2 The cardiovascular effects of alpha-methylnoradrenaline appeared to be restricted to the medio-caudal part of the NTS. 3 Prior administration of the alpha-adrenoceptor blocking agent, phentolamine, reversed the fall in blood pressure and heart rate induced by alpha-methylnoradrenaline into an increase. 4 Systemic administration of atropine combined with vagotomy potentiated the inhibitory effects of alpha-methylnoradrenaline on the cardiovascular system.
mesh_terms: D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D004837:Epinephrine / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects*; D007267:Injections; D008297:Male; D008526:Medulla Oblongata; D008771:Nordefrin / Q000008:administration & dosage / Q000494:pharmacology*; D009638:Norepinephrine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D051381:Rats; D013997:Time Factors; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D001285:Atropine; D008771:Nordefrin; D009638:Norepinephrine; D004837:Epinephrine; D010646:Phentolamine