Fig. 4.

Modulation of both integrated Ca²⁺ entry and ΔC_m was voltage-dependent. A, Superimposed traces from a single cell showing the effect of 2-MeSATP on ΔC_mevoked by a 200 msec depolarization to +20 mV from a holding potential of −90 mV with and without a 20 msec depolarizing prepulse.B, Top, Schematic diagram of prepulse (hashed line) voltage protocol. B,Bottom, Superimposed I_Ca used to evoke ΔC_m illustrated inA. Only the first 100 msec of the 200 msec test pulse are shown for clarity. C, Summary of the effects of 2-MeSATP on integrated Ca²⁺ entry and ΔC_m in the presence (open bars) or absence (filled bars) of a depolarizing prepulse (n = 9). Significant effects of 2-MeSATP on Ca²⁺ entry andC_m relative to control are indicated: ***p < 0.005; **p < 0.01; *p < 0.05. Significant differences between responses recorded with and without a prepulse are indicated by^φφφp < 0.005.