pKD or pKi values reported for muscarinic receptor antagonists at the five muscarinic receptor subtypes
Values shown are selected pKD (indicated by *) or pKi values. Where a range is given the mean value in parentheses was used for the correlation analysis. Only estimates obtained from studies that used a physiological buffer are included here.
| Antagonist | M1 | M2 | M3 | M4 | M5 |
|---|---|---|---|---|---|
| Atropinea | 9.4, r | 9.0, r | 9.3, r | 9.7, r | 9.4, r |
| Darifenacinb | 7.8, h | 7.0, h | 8.8, h | 7.7, h | 8.0, h |
| 4-DAMPa | 8.9, r | 8.2, r | 9.2, r | 9.1, r | 8.9, r |
| Himbacinea | 6.7, h | 7.9, h | 6.9, h | 7.8, h | 6.1, h |
| Methoctraminea | 6.7–7.0*, h (6.85) | 7.3*, h | 6.1–6.3*, h (6.2) | 7.0*, h | 6.3*, h |
| Pirenzepinea | 7.8, h | 6.0–6.4, h (6.2) | 6.6, h | 7.3, h | 6.6, h |
| p-F-HHSiDa | 7.5, h | 6.4, h | 7.6, h | 7.3, h | 6.3, h |
| HHSiDa | 7.7, h | 6.7–6.8, h (6.75) | 7.7, h | 7.7, h | 6.8, h |
r and h indicate studies using tissues containing muscarinic receptors taken from rats or humans, respectively.
↵a Values from the International Union of Basic and Clinical Pharmacology database, http://www.iuphar-db.org/DATABASE/FamilyMenuForward?familyId=2, for acetylcholine receptors (muscarinic).
↵b Values from Loury et al. (1999).