Potencies of the antimuscarinic ligands used in the present study assessed against human cloned muscarinic receptor subtypes
Human cloned receptors were expressed in Chinese hamster ovary cell membranes. Binding was measured as competition with [3H]N-methyl-scopolamine. Data represent the mean of three to six experiments ± S.E.M. expressed as Ki in nanomolar.
| Compound | hM1 | hM2 | hM3 | hM4 | hM5 | M2/M1 |
|---|---|---|---|---|---|---|
| Scopolamine | 0.83 (0.05) | 5.3 (1.4) | 0.34 (0.06) | 0.38 (0.07) | 0.34 (0.11) | 6.4 |
| Biperiden | 2.2 (0.23) | 102 (24) | 5.3 (1.3) | 3.1 (0.8) | 4.4 (1.4) | 46 |
| Pirenzepine | 43 (14) | 4200 (1370) | 468 (172) | 148 (53) | 237 (122) | 98 |
| VU0255035 | 124 (62) | 8530 (4000) | 2000 (628) | 2430 (854) | 4970 (1390) | 69 |
| SCH226206 | 1240 (255) | 30 (11) | 529 (194) | 76 (20) | 128 (14) | 0.02 |