PROPERTY OF RECEPTOR FOR VASOACTIVE INTESTINAL CONTRACTOR (VIC) EXPRESSED IN XENOPUS OOCYTES INJECTED WITH MESSENGER-RNA FROM RAT INTESTINE

Property of receptor for vasoactive intestinal contractor (VIC), a pep tide related to the endothelin family, expressed in Xenopus oocytes by injecting mRNA obtained from the intestine of rat, were studied using the voltage-clamp method. Inward-current responses to VIC (1 nM-100 n M) were evoked in a concentration-dependent manner in mRNA-injected oo cytes. Non-injected and water-injected oocytes failed to respond to VI C. The reversal potential for the VIC response was around -20 mV and t he depolarizing shift was approximately 18 mV, when the external conce ntration of Cl- was halved, in agreement with the Nernst equation. The response to VIC was suppressed either by the external application of BAPTA/AM (10 mu M) or by pertussis toxin (0.5 mu g/ml). These results indicate that the receptor for VIC, functionally expressed in Xenopus oocytes injected with rat intestinal mRNA, is coupled to pertussis tox in-sensitive G-protein and its activation leads to mobilization of int racellular Ca2+.