Inhibition constants of subtype-specific muscarinic antagonists in the synaptosomal fraction (P2) and the smooth muscle plasma membrane fraction (MIC2)
| Antagonist | Fraction | P2 | Fraction | MIC2 | n |
|---|---|---|---|---|---|
| log IC50 | pKi | log IC50 | pKi | ||
| Pirenzepine | 4.8 ± 0.1 | 5.3 ± 0.1 | 5.5 ± 0.1 | 5.9 ± 0.1 | 4 |
| Tripitramine | 8.2 ± 0.3 | 8.7 ± 0.3 | 8.4 ± 0.4 | 8.9 ± 0.4 | 6 |
| Methoctramine | 7.7 ± 0.06 | 7.9 ± 0.02 | 7.4 ± 0.01 | 7.8 ± 0.03 | 4 |
| Darifenacin | 6.8 ± 0.2 | 7.3 ± 0.2 | 6.8 ± 0.2 | 7.3 ± 0.2 | 6 |
| HHSiD | 5.9 ± 0.05 | 6.2 ± 0.1 | 5.9 ± 0.05 | 6.2 ± 0.06 | 4 |
Data are expressed as mean ± S.E.M. of four to six independent experiments.