Alteration by histamine-receptor blockers of the potentiation of angiotensin I in the pulmonary vascular bed.
The interaction of histamine receptor blockers and angiotensin I was studied in the isolated perfused pulmonary circulation of the rat lung. Rat colon and rabbit aorta were used as test organs, and they were continuously superfused with the effluent of lung. The response of rabbit aorta to the directly applied angiotensin II was found to be potentiated in the presence of histamine H2-receptor blockers but not H1-receptor blockers. No change was observed in rat colon in the presence of either H2- or H1-receptor blockers. Angiotensin I given through the lung caused an increased myotropic response in both assay when H2-receptor blocker was added to the perfusion medium. Histamine H1-receptor blockers did not change the potentiated response of the test organs to the angiotensin I-injected lung effluent. The possible mechanisms of the interaction of angiotensin I and histamine H2-receptor blockers are discussed.
D000803:Angiotensin I / Q000494:pharmacology*; D000809:Angiotensins / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000187:drug effects; D003106:Colon / Q000187:drug effects; D004347:Drug Interactions; D005260:Female; D006633:Histamine Antagonists / Q000494:pharmacology*; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D011652:Pulmonary Circulation / Q000187:drug effects*; D051381:Rats
D000809:Angiotensins; D006633:Histamine Antagonists; D006635:Histamine H2 Antagonists; D000803:Angiotensin I