Antagonist affinity constants (log affinity constants or pKBvalues) for mammalian muscarinic receptors3-a
| Antagonist | Receptor subtype | ||||
|---|---|---|---|---|---|
| M1 | M2 | M3 | M4 | M5 | |
| Atropine | 9.0–9.7 | 9.0–9.3 | 8.9–9.8 | 9.1–9.6 | 8.9–9.7 |
| Pirenzepine | 7.8–8.5 | 6.3–6.7 | 6.7–7.1 | 7.1–8.1 | 6.2–7.1 |
| Methoctramine | 7.1–7.8 | 7.8–8.3 | 6.3–6.9 | 7.4–8.1 | 6.9–7.2 |
| 4-DAMP | 8.6–9.2 | 7.8–8.4 | 8.9–9.3 | 8.4–9.4 | 8.9–9.0 |
| Himbacine | 7.0–7.2 | 8.0–8.3 | 6.9–7.4 | 8.0–8.8 | 6.1–6.3 |
| AF-DX 384 | 7.3–7.5 | 8.2–9.0 | 7.2–7.8 | 8.0–8.7 | 6.3 |
| Tripitramine | 8.4–8.8 | 9.4–9.6 | 7.1–7.4 | 7.8–8.2 | 7.3–7.5 |
| Darifenacin | 7.5–7.8 | 7.0–7.4 | 8.4–8.9 | 7.7–8.0 | 8.0–8.1 |
| Guanylpirenzepine | 7.7 | 5.5 | 6.5 | 6.5 | 6.8 |
| PD 102807 | 5.3 | 5.7 | 6.2 | 7.3 | 5.2 |
| MT33-b | 7.1 | <6 | <6 | 8.7 | <6 |
| MT73-b | 9.8 | <6 | <6 | <6 | <6 |
↵3-a Data are from a variety of mammalian species, including human: Hulme et al., 1990; Caulfield, 1993; Maggioet al., 1994; Eglen et al., 1996; Nunn et al., 1996; Adem and Karlsson, 1997; Caulfield, 1997; Levine and Birdsall, 1997; Jolkkonen et al., 1994.
↵3-b Toxins from Eastern Green Mamba venom.