Figure 6.

Graded Ca²⁺ release evoked by voltage-clamp pulses. (A) Voltage-clamp pulses for 50 ms were applied from a holding potential of −50 mV to various depolarized levels, from −38 to +30 mV, in increments of 2 mV. All recordings in all panels except for (D) are plotted with gradient colors from blue to red, coded in reference to the test potentials shown in (A). (B) Whole-cell I_CaL. (C) [Ca²⁺]_blk. (D) The voltage relationship of peak I_CaL (red) and peak d[Ca²⁺]_blk/dt (blue) was recorded with test pulses in 2 mV increments, normalized by each peak value. (E) Time evolution of Y_ooo, Y_cco, Y_oco, and Y_coo. (F) Ca²⁺ accumulation in jnc is represented by Ca₀₀.