| Abstract: | The effect of external pH on the amplitude of currents through single sodium channels in cultured mouse neuroblastoma cells C 1300, clone N18A-1 was studied. Currents through single sodium channels in outside-out membrane patches were measured at normal (7.2) and low (5.4) pH of the external solution. With a decrease of the external pH to 5.4, about two-fold reversible reduction of the amplitude of single sodium channel currents (at testing potentials of -10-30 mV) was observed. The data obtained confirm the suggestion that the inhibition of macroscopic sodium currents with lowering of pH of the extracellular solution is due to the decrease in the ionic current flowing through single open channels. |
