title: Mechanisms implicated in the histamine response of the sheep ureterovesical junction.
abstract: The isotonic response of the sheep ureterovesical junction to histamine receptor agonists and antagonists was studied in vitro. Histamine (10(-7)-10(-4) M) produced a concentration-dependent contraction which was dependent on the extracellular calcium concentrations. Nifedipine (10(-9)-10(-6) M) partially inhibited the contractile response to histamine. 2-Methylhistamine and 2-pyridylethylamine elicited contractile effect in a concentration-related manner. The order of potency was histamine greater than 2-methylhistamine greater than 2-pyridylethylamine. Dimaprit and 4-methylhistamine produced no response in this tissue. The histamine contraction was antagonized by mepyramine, the pA2 value being 8.41, but not by cimetidine (10(-4) M). Scopolamine (10(-5) M) and indomethacin (10(-6) M) had an inhibitory effect. Phentolamine (10(-5) M), propranolol (10(-7)) and hexamethonium (10(-6) M) did not alter the histamine-induced contractions. The present results indicate that the response to histamine in sheep ureterovesical junction is mediated mainly by a direct action on the smooth muscle through excitatory histamine H1-receptors and partly by an indirect action via the stimulation of intramural cholinergic nerves.
authors.affiliation: Department of Physiology, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Benedito
authors.forename: D
authors.initials: D
authors.lastname: Prieto
authors.forename: L
authors.initials: L
authors.lastname: Rivera
authors.forename: G
authors.initials: G
authors.lastname: Costa
authors.forename: A
authors.initials: A
authors.lastname: García-Sacristán
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000502:physiology; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000502:physiology; D011969:Receptors, Histamine H1 / Q000187:drug effects / Q000502:physiology; D011970:Receptors, Histamine H2 / Q000187:drug effects / Q000502:physiology; D012756:Sheep; D014513:Ureter / Q000187:drug effects* / Q000502:physiology; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology
chemical_list: D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D011969:Receptors, Histamine H1; D011970:Receptors, Histamine H2; D006632:Histamine; D002118:Calcium