Fig. 8. The effects of protein kinase C modulation on Ca²⁺ transients and STOCs. (A) Following depolarisation from a holding potential of -70 mV to -20 mV (iii), H-7 (10 µM), a protein kinase C inhibitor, had no significant effect on STOC frequency or amplitude (i) or on the ability of carbachol (CCh; iv) to inhibit these responses (i). (B) Following depolarisation from a holding potential of -70 mV to -18 mV, PKC_19-36 (3 mM), an impermeant PKC inhibitor added to the patch pipette, failed to affect the ability of either InsP₃ () or CCh (iv) to inhibit STOC frequency or amplitude (i). (C) Following depolarisation from a holding potential of -70 mV to -20 mV (iv) indolactam (10 µM), which activates protein kinase C, slightly decreased [Ca²⁺]_i (ii), did not alter the InsP₃-evoked Ca²⁺ transient (; ii) but significantly reduced STOC frequency (i), see text.