Figure 2. Effect of kurtoxin on the T-type calcium current in canine Purkinje cells.

A, kurtoxin selectively blocks the T-type component of the calcium current in Purkinje cells. The current was elicited by a test pulse at −25 mV from a holding potential of −90 mV, in control conditions and after the application of 200 nm kurtoxin, as indicated. Both the control and drug recordings were performed in the presence of 20 μm TTX (see Methods for rationale). B, time course for the T-type calcium current inhibition by kurtoxin. The horizontal bars on top of the graph indicate the bath solution applied. C, average current–voltage plots obtained in n = 3 cells under control conditions and after application of kurtoxin (see legend). The holding potential was −70 mV and test pulses were applied from −60 to +55 mV at 5 mV intervals. Error bars represent the s.e.m.