Figure 6. I_Cav activation by AP-waveform commands.

I_Cav activated by AP1 (A) and AP2 (B) commands. C and D show the corresponding cumulative Ca²⁺influx (Q_Cav). The dashed lines indicate the zero I_Cav or Q_Cav. E, a family of I_Cav traces activated by IV1 protocol, recorded in the same cell as panels A and C. F, comparison of I_Cav waveforms activated by AP commands and step depolarisations. Circles represent the voltage dependence of peak I_Cav traces activated by the depolarizing steps in E. Blue and red curves represent the I_Cavs activated by AP1 and AP2, plotted as a function of their voltage waveforms. The red arrows illustrate the direction of the current progression with time in response to AP2 command. Both currents loop clockwise, beginning and ending at the top left corner of the panel; the current activated by AP2 (red trace) has an additional anticlockwise loop, covering ∼−5 to +15 mV potential range, nested within the main current loop.