Effects of SNP on KCa currents in outside-out membrane patches of vascular SMCs. (a) SNP increased, but the subsequently applied IbTX blocked the single channels in the same membrane patch. The dashed lines beside each trace indicate the closed channel level. (b) The concentration-dependent excitatory effect of SNP on the NPo of KCa channels. n = 6 for each data point. A total of three batches of cells were used in this study. Membrane potential, –30 mV. *P < 0.05 vs. control. ms, millisecond; pA, picoampere.