Figure 4.
Effect of VILIP-2 on CaV2.1/β2a channels after trains of repetitive depolarizations. CaV2.1/β2a channel currents were evoked by 1 s test pulses to +10 mV before (gray) or after (black) a 600 ms train of 5 ms depolarizations to +20 mV (+10 mV for IBa) at 100 Hz. A 2 min interval was maintained between applications of this protocol to allow the effects of the previous stimuli to return to baseline. Current amplitudes were normalized to the peak current of the first test pulse. Mean normalized currents during test pulse 1 (gray) and test pulse 2 (black) are overlaid. A, ICa, CaV2.1/β2a alone. B, IBa, CaV2.1/β2a alone. C, ICa, CaV2.1/β2a plus VILIP-2. D, IBa, CaV2.1/β2a plus VILIP-2. E, Bar graph presenting facilitation as the pulse ratio (P2/P1) at the time of the peak current in each panel (mean ± SEM). Error bars represent SEM.