Table 1.
Electrophysiological Parameters
| Channel | f or f′ | IBa/ICa | Erev | V1/2 | k | n | |
|---|---|---|---|---|---|---|---|
| Oocytes | CaV1.2 | 0.61 ± 0.02 | 1.72 ± 0.11 | 89.1 ± 4.0 | 5.4 ± 0.6 | 9.5 ± 0.3 | 8 |
| D707A | 0.10 ± 0.01 | 1.53 ± 0.05 | 92.8 ±4.8 | 5.2 ± 0.9 | 9.8 ± 0.5 | 13 | |
| D707G | 0.24 ± 0.03 | 1.94 ± 0.13 | 94.8 ± 4.0 | 7.2 ± 0.8 | 9.0 ± 0.6 | 5 | |
| D707N | 0.49 ± 0.04 | 2.63 ± 0.03 | 87.8 ± 2.5 | 10.0 ± 0.6 | 9.8 ± 0.5 | 5 | |
| D707E | 0.35 ± 0.02 | 3.58 ± 0.24 | 88.0 ± 8.1 | 8.5 ± 1.0 | 8.7 ± 0.5 | 6 | |
| E1115A | 0.14 ± 0.02 | 0.92 ± 0.01 | 49.8 ± 1.0 | 1.7 ± 0.3 | 8.6 ± 0.2 | 8 | |
| G364D-D707G | 0.30 ± 0.02 | 2.98 ± 0.26 | 88.7 ± 6.1 | 10.4 ± 1.2 | 9.3 ± 0.2 | 7 | |
| D707G-G1116D | 0.60 ± 0.02 | 2.28 ± 0.29 | 89.2 ± 4.3 | 4.8 ± 3.3 | 8.1 ± 0.6 | 6 | |
| D707A-A1417D | 0.45 ± 0.01 | 1.63 ± 0.14 | 83.9 ± 4.2 | 5.2 ± 1.1 | 8.9 ± 0.4 | 9 | |
| E1119A | 0.59 ± 0.02 | 1.73 ± 0.18 | 88.9 ± 3.6 | 6.3 ± 1.1 | 9.1 ± 0.2 | 6 | |
| D1420A | 0.60 ± 0.02 | 1.88 ± 0.23 | 79.3 ± 2.7 | 5.8 ± 1.9 | 10.0 ± 0.2 | 5 | |
| HEK293 | CaV 1.2 | 0.59 ± 0.02 | 1.57 ± 0.38 | 77.5 ± 3.0 | 7.1 ± 2.0 | 6.5 ± 0.6 | 8 |
| D707A | 0.17 ± 0.02 | 1.94 ± 0.21 | 80.5 ± 1.8 | 11.8 ± 0.5 | 8.7 ± 0.2 | 6 | |
| D707E | 0.40 ± 0.04 | 2.86 ± 0.52 | 73.3 ± 2.9 | 11.3 ± 2.1 | 6.8 ± 0.5 | 4 | |
| E1115A | 0.36 ± 0.04 | 1.00 ± 0.15 | 68.5 ± 1.5 | −0.5 ± 2.0 | 7.8 ± 0.5 | 6 | |
| CaV1.3 | 0.73 ± 0.01 | 1.58 ± 0.11 | 75.6 ± 3.0 | −8.5 ± 1.1 | 7.3 ± 0.5 | 6 | |
| D726A | 0.15 ± 0.05 | 1.85 ± 0.16 | 81.1 ± 1.3 | −8.6 ± 0.9 | 7.1 ± 0.4 | 8 | |
| E1121A | 0.63 ± 0.02 | 1.09 ± 0.08 | 61.9 ± 3.0 | −15.3 ± 1.7 | 7.8 ± 0.4 | 9 | |
| CaV2.1 | 0.26 ± 0.03 | 1.64 ± 0.39 | 46.9 ± 7.0 | −7.7 ± 0.8 | 3.2 ± 0.6 | 7 | |
| D667A | 0.04 ± 0.03 | 1.81 ± 0.12 | 56.4 ± 3.2 | −4.7 ± 1.4 | 3.8 ± 0.9 | 6 | |
| E1461A | 0.12 ± 0.02 | 1.07 ± 0.13 | 34.0 ± 1.2 | −8.8 ± 0.5 | 3.4 ± 0.2 | 5 |
f is defined as R300 for Ba2+ – R300 for Ca2+ where R300 = I300/I0 where I300 and I0 are current amplitudes at 300 ms post-depolarization and at the peak current, respectively. f′ is defined as R800 for Ba2+ – R800 for Ca2+ where R800 = I800/I0 where I800 and I0 are current amplitudes at 800 ms post-depolarization and at the peak current, respectively. f and f′ were determined at membrane potential of +20 and +10 mV, respectively. IBa/ICa is the Ba2+ and Ca2+ peak current amplitude ratio. Erev is the reversal potential. V1/2 is the midpoint of activation. k is the slope factor of the activation curve. Erev, V1/2, and k were determined using Ca2+ as the charge carrier. n is the number of experiments. Data were fit to I = Gmax * (Vm − Erev)/(1 + exp (V1/2 − Vm)/k), where I is the measured peak current at each test potential (Vm) and Gmax is the maximal macroscopic conductance. Data are expressed as mean values ± SEM.