Figure 8.

Effects of orthovanadate on I_f. (A) The time course of If in the absence (open circles) and in the presence of orthovanadate (filled circles). The pulse protocol was the same as shown in Figure 6. The I_f amplitude was normalized to that of the first record in each experiment. The data are mean±s.e.mean of five cells. (B) After the intra- (0.2 mM) and extra-cellular (2 mM) application of orthovanadate for 20 min, 100 μM genistein was applied during the period shown by the horizontal bar. The pulse protocol was the same as shown in Figure 6. The I_f amplitude was measured as the time dependent component of hyperpolarization activated inward current. (C) Summarized results obtained from five cells. The I_f amplitude was normalized to that recorded immediately after the start of the experiments. Each column indicates mean±s.e.mean.