Abstract: | The action of a raised intracellular pH (pHi) on transmembrane ionic currents was investigated on isolated unidentified neurons ofHelix pomatia under intracellular dialysis and membrane voltage clamping conditions. With a rise in pHi from 7.3 to 9.0 and in the simultaneous presence of an inward calcium current, the outward potassium current was considerably reduced and the current-voltage characteristic curve was shifted toward more positive membrane potential values. The inward calcium current was practically unchanged in this case. If, however, the calcium current was inhibited by the action of cadmium ions, no decrease in the outward current was observed, only a shift of the IK(V) curve toward more positive values of membrane potential. It is suggested that an increase in pHi selectively blocks the Ca-dependent component of the outward potassium current.A. A. Bogomolets Institute of Physiology, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Neirofiziologiya, Vol. 14, No. 4, pp. 426–430, July–August, 1982. |