title: Vasopressin V1-receptor stimulation produces a positive inotropic response without affecting pHi in guinea pig papillary muscles.
abstract: Effects of arginine-vasopressin (AVP) on the contractile force, action potential (AP) and intracellular pH (pHi) were studied in isolated guinea pig papillary muscles using conventional and ion-selective microelectrode techniques. AVP increased the developed tension and the resting tension, and these responses were attenuated by the V1-receptor antagonist OPC-21268 (1-(1-[4-(3-acetylaminopropoxy)benzoyl]-4-piperidyl)-3,4-dihydro-2 (1H)- quinolinone). However, AVP failed to affect AP configuration or pHi. These results suggest that AVP produces a positive inotropy by mechanism(s) other than intracellular alkalinization.
authors.affiliation: Department of Pharmacology, School of Medicine, Chiba University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: H
authors.initials: H
authors.lastname: Uemura
authors.forename: T
authors.initials: T
authors.lastname: Saito
authors.forename: Y
authors.initials: Y
authors.lastname: Masuda
authors.forename: H
authors.initials: H
authors.lastname: Nakaya
mesh_terms: D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D009200:Myocardial Contraction / Q000187:drug effects*; D010210:Papillary Muscles / Q000187:drug effects / Q000378:metabolism; D017483:Receptors, Vasopressin / Q000187:drug effects*; D013268:Stimulation, Chemical; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D017483:Receptors, Vasopressin; D014662:Vasoconstrictor Agents; D001127:Arginine Vasopressin