Fig. 6.

L-type Ca_V current is inhibited when IP₃-generating agonists are applied. A and B: currents were evoked by steps from −60 to 0 mV under control conditions and were reduced in the presence of carbachol. C and D: although inhibition of Ca²⁺ release from IP₃ receptors (IP₃Rs) with 2-APB had little effect on the L-type Ca_V current, it blocked the inhibitory effect of carbachol. E: summary for 5 experiments in which the peak inward current was measured in the absence of drugs (control) and in the presence of carbachol, 2-APB, and carbachol + 2-APB. **P < 0.01 (by ANOVA using Dunnett's post hoc test).