On the inotropic actions of arginine vasopressin in ventricular muscle of the guinea pig heart.
Arginine vasopressin (AVP) (0.03-3 microM) produced transient negative responses that were followed by slowly developing positive inotropic responses in guinea pig papillary muscles. The inotropic responses were antagonized by OPC-21268 (10 microM), but not by OPC-31260, and suppressed by neomycin (3 mM). The negative inotropic response was hardly affected by staurosporine (10 nM) and H-7 (10 microM). AVP (1 microM) elicited a transient decrease followed by a slowly developing increase in I(Ca). The latter increase in I(Ca) was not elicited in the presence of staurosporine (1 nM). These results indicate that AVP stimulates V1 receptors that couple to phosphoinositide hydrolysis and thereby increases intracellular Ca2+ and activates protein kinase C.
Fujisawa
S
S
Department of Pharmacology, Akita University School of Medicine, Japan.
Iijima
T
T
D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000494:pharmacology*; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000187:drug effects*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology; D016276:Ventricular Function
D065092:Antidiuretic Hormone Receptor Antagonists; D010880:Piperidines; D015363:Quinolones; D001127:Arginine Vasopressin; C068644:OPC 21268; D019311:Staurosporine