Figure 10. R-type channels contribute to activation of the currents underlying afterpotentials.

A, averaged inward tail currents from four cells in the presence of apamin were markedly reduced, but not completely abolished, in the presence of 40 nmωAga IVA and 10 μm nifedipine. B, averaged outward tail currents from three cells in the presence of 9AC were markedly reduced, but not completely blocked, in the presence of 10 μm nifedipine and 300 nmωCgtx GVIA. Subsequent addition of 300 μm Cd²⁺ blocked the remaining outward currents.