“Certain blockers of K+ channels, for example charybdotoxin (5-50 …), Ba2+ (5-20 mM), 4-aminopyridine (5-10 mM) and quinidine (0.1-0.5 mM) reversibly … the membrane potential response to bradykinin or to Ins-P3; however, apamin (1 microM) … D-tubocurarine (0.5 mM) had no effect.”