Fig. 4.

tBK current depends on Ca²⁺ release via ryanodine receptors. Ai: effect of caffeine application after currents were evoked by steps from −60 to 0 mV. Aii: caffeine-sensitive difference current obtained by digital subtraction of traces in Ai. Aiii: summary data for 4 experiments in which peak tBK current was measured before (control) and after caffeine application. Bi: tBK current was also blocked in the presence of ryanodine. Bii: ryanodine-sensitive difference current. Biii: summary data for 7 experiments in which peak tBK current was measured before (control) and after ryanodine application. *P < 0.05, **P < 0.01 (by paired t-test).