Table 7.
IC50 values for inhibition of rat α6/α3β4 mutants and α6/α3β2β3 nAChRs by α-Ctxs
Values in parentheses indicate the 95% CI of the data obtained from at least four oocytes per IC50 determination. The log(IC50 ratio) was calculated by dividing the IC50 value for each nAChR:α-Ctx combination (nAChR:PeIA analog, nAChR mutant:α-Ctx, or nAChR mutant:PeIA analog) by the IC50 for the WT:WT combination; negative values indicate higher potency, and positive values indicate lower potency. The -fold change in IC50 = nAChR:PeIA analog/WT:WT, nAChR mutant:α-Ctx/WT:WT, or nAChR mutant:PeIA analog/WT:WT. Differences between IC50 values are considered substantial if ≥0.5 log units or ≥3-fold. WT, WT receptor or WT α-Ctx.
| nAChR:α-Ctx | IC50 | Log (IC50 ratio) | Change in IC50 |
|---|---|---|---|
| nm | -fold | ||
| α6/α3β4:PeIA | 154 (143–166)a | ||
| α6/α3β4Q119L:PeIA | 203 (166–250)a | 0.1 | 1 |
| α6/α3β4:[P13Q]PeIA | 8,231 (5,784–11,710)a | 1.7 | 53 |
| α6/α3β4Q119L:[P13Q]PeIA | >10,000 | >1.8 | >65 |
| α6/α3β4:[P13R]PeIA | 51,780 (29,710–90,270)a | 2.5 | 336 |
| α6/α3β4Q119L:[P13R]PeIA | >10,000 | >1.8 | >65 |
| α6/α3β4Q119F:PeIA | 241 (212–274)a | 0.2 | 2 |
| α6/α3β4Q119F:[P13Q]PeIA | 35,170 (24,000–51,520) | 2.4 | 228 |
| α6/α3β4Q119F:[P13R]PeIA | >10,000 | >1.8 | >65 |
| α6/α3β2β3:PnIA | 3.3 (3.0–3.6)a | ||
| α6/α3β4:PnIA | 8,456 (5,419–13,290)a | ||
| α6/α3β4Q119L:PnIA | 942 (744–1,192) | −1.0 | 0.1 |
| α6/α3β4Q119F:PnIA | 684 (533–878) | −1.1 | 0.1 |
a Data previously shown for ease of comparison.