Effects of vasopressin on phosphoinositide hydrolysis and myocardial contractility.
The effects of vasopressin on phosphoinositide hydrolysis, ventricular contractility and adrenoceptor-mediated inotropy were studied in the rabbit. Vasopressin caused an accumulation of [3H]inositol monophosphate in ventricular slices prelabelled with myo-[3H]inositol, whereas it elicited a small but definite negative inotropic effect. In addition, vasopressin attenuated the positive inotropic effect elicited via alpha 1- and endothelin receptors without affecting the beta-adrenoceptor-mediated effect. The nonpeptide-selective V1 receptor antagonist OPC 21268 (a quinolinone derivative) inhibited the vasopressin-induced accumulation of [3H]inositol monophosphate. The present results indicate that vasopressin stimulates phosphoinositide hydrolysis via V1 receptors, but inhibits force and the alpha 1-mediated positive inotropic effect in the rabbit ventricular myocardium.
Endoh
M
M
Department of Pharmacology, Yamagata University School of Medicine, Japan.
Takanashi
M
M
Norota
I
I
D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006352:Heart Ventricles / Q000187:drug effects / Q000294:innervation; D006868:Hydrolysis / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010716:Phosphatidylinositols / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D015363:Quinolones / Q000494:pharmacology; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011943:Receptors, Adrenergic, beta / Q000187:drug effects
D065092:Antidiuretic Hormone Receptor Antagonists; D010716:Phosphatidylinositols; D010880:Piperidines; D015363:Quinolones; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D001127:Arginine Vasopressin; C068644:OPC 21268