Summary of IBa inhibition by baclofen and c-Vc1.1 in HEK 293T cells transiently coexpressing GABABRs and Cav2.1 or Cav2.3 channels
| Cav2 channel | IBa inhibition (%) | |
| c-Vc1.1 (200 nM) | Baclofen (50 µM) | |
| Human Cav2.3d | 23 ± 2.9 (8) | 33.1 ± 1.8 (8) |
| Human Cav2.3d (Y1761F) | 1.7 ± 0.3 (11)a | 21.9 ± 1.8 (11)c |
| Human Cav2.3d (Y1765F) | 11.3 ± 3.0 (10)b | NS28.9 ± 2.7 (10) |
| Human Cav2.3c | 28.0 ± 4.0 (10) | 44.0 ± 3.0 (10) |
| Human Cav2.3c (Y1761F) | 0.37 ± 0.3 (8)a | 14.6 ± 1.8 (8)c |
| Human Cav2.3c (Y1765F) | 15.0 ± 3.2 (10)b | 28.9 ± 2.7 (10)d |
| Human Cav2.1 | 0 (8) | 44.4 ± 1.9 (9) |
| Human Cav2.1 (L1852T) | 7.2 ± 1.4 (8)a | NS50.6 ± 2.8 (8) |
| Human Cav2.1 (Q1856E) | 6.6 ± 1.7 (8)b | NS47.9 ± 3.0 (8) |
| Rabbit Cav2.1 | #20.0 ± 4.0 (7) | #50.0 ± 5.0 (8) |
| Cav2 channel | IBa inhibition (%) | |
| c-Vc1.1 (200 nM) | Baclofen (50 µM) | |
| Human Cav2.3d | 23 ± 2.9 (8) | 33.1 ± 1.8 (8) |
| Human Cav2.3d (Y1761F) | 1.7 ± 0.3 (11)a | 21.9 ± 1.8 (11)c |
| Human Cav2.3d (Y1765F) | 11.3 ± 3.0 (10)b | NS28.9 ± 2.7 (10) |
| Human Cav2.3c | 28.0 ± 4.0 (10) | 44.0 ± 3.0 (10) |
| Human Cav2.3c (Y1761F) | 0.37 ± 0.3 (8)a | 14.6 ± 1.8 (8)c |
| Human Cav2.3c (Y1765F) | 15.0 ± 3.2 (10)b | 28.9 ± 2.7 (10)d |
| Human Cav2.1 | 0 (8) | 44.4 ± 1.9 (9) |
| Human Cav2.1 (L1852T) | 7.2 ± 1.4 (8)a | NS50.6 ± 2.8 (8) |
| Human Cav2.1 (Q1856E) | 6.6 ± 1.7 (8)b | NS47.9 ± 3.0 (8) |
| Rabbit Cav2.1 | #20.0 ± 4.0 (7) | #50.0 ± 5.0 (8) |
Values represent mean ± SEM; n, number of experiments in parentheses. NS, not significantly different from wild-type modulation. One-way ANOVA with Bonferroni post-hoc testing was used to test for statistically significant differences except when comparing the effect of c-Vc1.1 on wild-type or mutant Cav2.1 (one-way ANOVA on ranks with Tukey test). Data marked with a hash symbol were not included in the statistical analysis. Note that the percentage of inhibition with transiently expressed human Cav2.1 or Cav2.3c channels and transiently coexpressed GABABRs (above) is similar (within the statistical margin of error) to that obtained with stably expressed human Cav2.1 or Cav2.3c channels in the presence of transiently coexpressed GABABRs (see Table 1).
P < 0.001 versus Cav2.3d with c-Vc1.1; P < 0.001 versus Cav2.3c with c-Vc1.1; and P = 0.002 versus human Cav2.1 with c-Vc1.1.
P = 0.003 versus Cav2.3d with c-Vc1.1; P = 0.008 versus Cav2.3c with c-Vc1.1; and P = 0.002 versus human Cav2.1 with c-Vc1.1.
P = 0.003 versus Cav2.3d with baclofen and P < 0.001 versus Cav2.3c with baclofen.
P < 0.001 versus Cav2.3c with baclofen.