title: The vascular responses of the isolated perfused bovine external ear to exogenous histamine and 5-HT (serotonin).
abstract: The responses of the vasculature of isolated, non-sensitized, bovine external ears to histamine and serotonin (5-HT) were evaluated while they were being perfused with Krebs-Henseleit solution. Histamine (10(-5) mol/L to 5 x 10(-3) mol/L) and 5-hydroxytryptamine (5-HT) (10(-9) mol/L to 10(-2) mol/L) caused increased vascular resistance. Mepyramine (10(-7) mol/L), cimetidine (10(-5) mol/L) and atropine (10(-6) mol/L) inhibited the responses to histamine. The responses to 5-HT were inhibited by methysergide (10(-9) mol/L) and potentiated by morphine (10(-5) mol/L). These results suggest the presence of H1 and H2 histamine, and 5-HT receptors in bovine auricular vessels, all of which cause net vasoconstriction.
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Canada.
authors.forename: K I
authors.initials: KI
authors.lastname: Eghianruwa
authors.forename: P
authors.initials: P
authors.lastname: Eyre
mesh_terms: D000818:Animals; D002417:Cattle; D004431:Ear, External / Q000098:blood supply; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006633:Histamine Antagonists / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008954:Models, Biological; D010477:Perfusion / Q000662:veterinary; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D012867:Skin / Q000098:blood supply*; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D006633:Histamine Antagonists; D012702:Serotonin Antagonists; D012701:Serotonin; D006632:Histamine