Figure 6. Effects of 18β-GA on electrical coupling between bladder smooth muscle cells.

In the presence of nifedipine (10 μM), two independent electrodes were placed axially with a measured separation. Hyperpolarizing currents, with amplitudes of 0.5 nA, caused a hyperpolarization detected at the second electrode (Aa). 18β-GA (40 μM) depolarized the membrane and abolished the electrotonic potential (Ab). After washing out 18β-GA, the membrane potential recovered to the original level and the electrotonic potential was restored (Ac). In a separate preparation, almost identical membrane potential changes were recorded from both electrodes (Ba andb). 18β-GA (40 μM) depolarized the membrane and increased the amplitude of membrane potential changes in both cells (Bc andd). Each trace represents the mean of 8-10 recordings. Scale bar on the right of Ac refers to all traces in A. Scale bar on the right of Bd refers to all traces in B.