title: Effect of histamine on aorta preparations of different species.
abstract: The effect of histamine (10(-8) to 10(-3)M) on aorta preparations of 5 different species was studied. In aortic ring segments, precontracted by norepinephrine, three types of dose-response curves were found: relaxation (rat), contraction (guinea-pig, cat, mouse) and relaxation followed by contraction at higher doses (rabbit). In relaxed preparations, histamine either had no effect (rat) or elicited a contraction (rabbit, guinea-pig). All the contraction effects proved to be H1-mediated as they were antagonized by mepyramine. These contraction effects were maintained or even increased after rubbing the endothelial surface of the vessel, which suggests a direct action on muscular structures. The differences between the species in the dose-response curves to histamine appeared to be determined by the role of the endothelial structures, which can induce an H1-mediated (rat) or an H2-mediated (rabbit) relaxation or may have no influence (guinea-pig).
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D002415:Cats; D002927:Cimetidine / Q000494:pharmacology; D006168:Guinea Pigs; D006632:Histamine / Q000494:pharmacology*; D066298:In Vitro Techniques; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011738:Pyrilamine / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D013045:Species Specificity
chemical_list: D002927:Cimetidine; D006632:Histamine; D011738:Pyrilamine; D000109:Acetylcholine; D009638:Norepinephrine