EFFECTS OF AN ORALLY ACTIVE VASOPRESSIN V1 RECEPTOR ANTAGONIST

Abstract

1. This paper reports on the in vitro and in vivo characteristics of a non‐peptide vasopressin V1 receptor antagonist 1‐{1‐[4‐(3‐acetylaminopropoxy)benzoyl]‐4‐piperidyl}‐3,4‐dihydro‐2(1H)‐quinolinone (OPC‐21268). 2. OPC‐21268 caused a concentration‐dependent displacement of the selective V1 receptor antagonist radioligand, [125I]‐[d(CH2)5, sarcosine7]AVP from vasopressin V1 receptors in rat liver and kidney membranes, inhibitory concentration of 50% (IC50) 4 ± 10‐8, 0.3 mol/L liver and 1.5 ± 10‐8, 0.2 mol/L kidney. OPC‐21268 had little effect on the selective V2 antagonist radioligand [3H]desGly‐NH29‐d(CH2)5[d‐Ileu2, Ileu4]AVP binding to V2 receptors in renal membranes (IC50 > 10‐4 mol/L). 3..