Table 2.
Dissociation constants (Ki) for muscarinic receptor antagonists in human detrusor muscle membranes
| Drug | N | Hill slopea | Ki (nM)b | Ki site 1 | Ki site 2 | % Ha, c |
|---|---|---|---|---|---|---|
| Atropine | 4 | 0.82±0.10 | 3.0 (2.1–4.3) | N/A | ||
| Trospium | 7 | 0.66±0.06 | 4.9 (3.6–6.7) | N/A | ||
| AQ-RA 741 | 6 | 0.73±0.03 | 12.3 (10.8–14.1) | 4.5 (2.8–7.2) | 97.5 (39.8–238) | 65±9 |
| 4-DAMP | 4 | 0.63±0.05 | 12.2 (9.2–16.4) | 0.23 (0.05–1.19) | 29.5 (18.5–47.1) | 22±6 |
| Methoctramine | 12 | 0.65±0.03 | 38.6 (33.4–44.7) | 13.7 (9.9–18.9) | 752 (336–1680) | 71±5 |
| Darifenacin | 11 | 0.52±0.05 | 42.0 (33.6–52.6) | 0.23 (0.11–0.53) | 146 (113–189) | 24±3 |
| AF-DX 116 | 6 | 0.75±0.05 | 170 (140–208) | N/A | ||
| Pirenzepine | 8 | 0.78±0.04 | 856 (734–998) | 0.42 (0.06–3.10) | 1134 (962–1340) | 8±2 |
Ki values were calculated according to the equation Ki=IC50/(1+200/77.1).
a
Data are expressed as mean±s.e.m.
b
Data are derived from simultaneous analysis of all competition curves and are expressed as geometric mean (95% confidence intervals).
c
% H, indicates % of high-affinity sites.