TABLE II.
CaV1.2 and Mutant CaV1.2 G-V Relationships
| Ba2+ | Ca2+ | |||
| Construct | V0.5 (mV) | Ka | V0.5 (mV) | Ka |
| CaV1.2, β2a | −2.1 ± 3.1 | 7.0 ± 0.5 | 7.8 ± 2.6 | 9.2 ± 0.8 |
| CaV1.2 AAA, β2a | −0.7 ± 4.4 | 6.7 ± 1.2 | 7.6 ± 2.9 | 8.7 ± 0.8 |
| CaV1.2 | 11.2 ± 3.2 | 8.2 ± 1.0 | 21.0 ± 1.7 | 10.1 ± 0.5 |
| CaV1.2 HotA, β2a | 9.6 ± 4.3 | 8.1 ± 1.4 | 20.9 ± 1.4 | 10.2 ± 0.4 |
| CaV1.2 GGG, β2a | 8.2 ± 2.5 | 8.0 ± 0.8 | 16.8 ± 3.2 | 9.9 ± 0.7 |
| CaV1.2 6G, β2a | 4.7 ± 2.4 | 7.7 ± 0.9 | 18.4 ± 2.0 | 9.7 ± 0.9 |
| CaV1.2 GGG | 8.8 ± 3.9 | 8.8 ± 1.0 | 16.5 ± 3.4 | 10.7 ± 0.8 |
V0.5 and slope factor values for CaV1.2 and mutants in barium and calcium. Data were fit using the equation I = Gmax * (Vm − Vrev)/(1 + exp (V0.5 − Vm)/Ka), where I is the measured peak current at each Vm, Gmax is the maximal conductance, Vm is the test potential, Vrev is the reversal potential, V0.5 is the midpoint of activation, and Ka is the slope factor (Kanevsky and Dascal, 2006). n-values are identical to the values for equivalent constructs in Table I.