Figure 6.

Cytosolic alkaline pH inhibits I_AP. (A) Representative I_AP recorded under pH_i 8.3 (Upper) and pH_i 7.1 (Lower). (B) I_AP at +100 mV measured under various pH_i from 7.1 to 8.3. The voltage protocol was the same in A and B as given in Fig. 1B, but only current traces at +100 mV are shown in B. (C) Effect of pH_i on I_AP peak amplitudes at +100 mV from experiments as performed in B (n = 4–12). Pipette solutions with nominally zero free Ca²⁺ concentrations and varied pH_i, and standard bath solution were used.