Fig. 5.

Effect of xestospongin C and 2-APB on voltage-gated Ca²⁺ current (I_Ca). I_Ca was recorded under whole-cell voltage clamp in response to 500-ms steps to 0 mV, applied every 30 s from V_h = −80 mV, in Cs⁺/Na⁺-containing solutions (see Section 2). The traces (A) show I_Ca evoked by the first step (black) and the step applied 10 min after (grey) in control (a), in 2 μM xestospongin C (b) and in 30 μM 2-APB (c). The normalized peak I_Ca (I_test/I_first) is plotted over time (B) in control (circle, n = 7), in 2 μM xestospongin C (triangle, n = 4) and in 30 μM 2-APB (square, n = 5). The drug application moment is depicted by the arrow.