ADP indirectly supports activation of non-selective cation channels by AlF complex in guinea-pig chromaffin cells.

Infusion of the G protein activator, AlF complex, into guinea-pig adrenal chromaffin cells produced an inward non-selective cation current (INS) at -55 mV. Under metabolically suppressed conditions, this current was abolished by removal of ATP from the AlF-containing pipette solution. ADP could substitute for ATP in generation of the current. This supporting action of ADP was eliminated by addition to the AlF solution of the ATP-consuming system (hexokinase and 2-deoxyglucose). A similar generation of INS occurred when AMP and phosphocreatine were simultaneously added to AlF solution, but not when either of the agents was added separately. These results suggest that under conditions of whole-cell current recordings, the machinery for ATP production is preserved and that ADP indirectly supports generation of INS by the AlF complex.