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. 2001 Apr 10;98(8):4699–4704. doi: 10.1073/pnas.051628998

Figure 2.

Figure 2

Facilitation of Cav2.1 and Cav2.2a. (A) Prepulse facilitation of Cav2.1 channels. A 4-ms test pulse (test 1) to the indicated test potential was applied from the holding potential of −60 mV. After 1 s, a 10-ms conditioning prepulse to +100 mV was applied, the cell was repolarized to −60 mV for 10 ms, and a second 4-ms test pulse (test 2) identical to test-pulse 1 was applied. Means ± SEM of Ba2+ tail currents were plotted against test-pulse potentials. ○, test 1; ●, test 2. (B) Prepulse facilitation of Cav2.2a channels. As in A, except 10-ms test pulses were used, and the repolarization was for 1 ms to −70 mV. ○, test 1; ●, test 2. Current traces shown above A and B were recorded during and after test 1 and test 2 at +30 mV. (C) Voltage dependence of facilitation. A 4-ms (α1) or 10-ms (Cav2.2a) test pulse to +30 mV was applied from the holding potential of −60 mV (Cav2.1) or −70 mV (Cav2.2a). After 1 s, a 10-ms conditioning prepulse to the indicated potential was applied, the cell was repolarized to −60 mV (Cav2.1) for 10 ms or −70 mV (Cav2.2a) for 1 ms, and a second 4-ms (Cav2.1) or 10-ms (Cav2.2a) test pulse (test 2) to +30 mV was applied. Peak tail currents following each test pulse were measured. The facilitation ratio was calculated by dividing currents in test 2 by the currents in test 1, and means ± SEM of normalized facilitation ratios were plotted against the conditioning pulse potential. ●, Cav2.1; ○, Cav2.2a.