THE P-2Y PURINOCEPTOR-OPERATED POTASSIUM CHANNEL IS POSSIBLY REGULATED BY THE BETA-GAMMA-SUBUNITS OF A PERTUSSIS TOXIN-INSENSITIVE G-PROTEIN IN CULTURED RAT INFERIOR COLLICULUS NEURONS

In whole-cell patches of inferior colliculus neurons, ADP evoked outwardly rectifying potassium currents with a latency of <1 sec via P-2Y purinoceptor. These currents were blocked by GDP beta S, while not by pertussis toxin (PTX). Additionally, a selective protein kinase C inhibitor, GF109203X, or a selective phospholipase A(2) inhibitor, BPB, had no effect on the currents. In outside-out patches, ADP elicited single channel currents with same slope conductances as those obtained in cell-attached patches and the currents were again blocked by GDP beta S. The results presented here indicate that the P-2Y purinoceptor-operated potassium channel in inferior colliculus neurons is activated only by a plasma membrane component, most likely by a direct coupling to the beta gamma subunits of a PTX-insensitive G-protein. (C) 1995 Academic Press, Inc.