抄録
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 ionselective 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.
