Histamine, histamine antagonists and regional blood flow.
The effects of mepyramine, a selective histamine H1-receptor antagonist, and metiamide, a selective histamine H2-receptor antagonist, have been determined on the cardiovascular response to intravenous infusions of a large dose of histamine, 1 X 10(-7) mol/kg/min. Pretreatment with either mepyramine, 2.5 X 10(-6) mol/kg, or metiamide, 2 X 10(-6) mol/kg/min, had no significant effect on the fall in blood pressure or fall in total peripheral resistance during histamine infusion. Pretreatment with mepyramine, 2.5 X 10(-6) mol/kg, and metiamide, 2 X 10(-6) mol/kg/min, abolished the fall in blood pressure and total peripheral resistance during infusion of histamine. Histamine-induced vasodilatation in the stomach was unaltered by pretreatment with mepyramine but abolished by pretreatment with metiamide. Histamine-induced coronary vasodilation was reduced slightly by pretreatment with mepyramine and substantially by pretreatment with metiamide. Coronary vasodilatation was abolished by treatment with mepyramine and metiamide.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D004347:Drug Interactions; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006632:Histamine / Q000494:pharmacology*; D008297:Male; D008785:Metiamide / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology*; D011738:Pyrilamine / Q000494:pharmacology*; D012039:Regional Blood Flow / Q000187:drug effects; D013890:Thiourea / Q000031:analogs & derivatives*; D014655:Vascular Resistance / Q000187:drug effects
D011725:Pyridines; D008785:Metiamide; D006632:Histamine; D013890:Thiourea; D011738:Pyrilamine