Figure 8. Isoprenaline-induced increase of the nicardipine-sensitive currents at 0.1 mM [Ca²⁺]_o.

A and B, I_Ca,L was suppressed by decreasing [Ca²⁺]_o to 0.1 mM, and the sustained inward current was obtained as the difference between the control (^) and that in the presence of 1 μM nicardipine (•) at test potentials indicated. The recording was repeated before (A) and during (B,^) the application of 100 nM isoprenaline in the same cell (input capacitance = 61 pF). The holding potential was -80 mV and the pulse duration was 800 ms. C, I-V relationships of the nicardipine-sensitive late current obtained in a different cell from that in A at 0.1 mM [Ca²⁺]_o (input capacitance = 62 pF).