Parameters of [3H]RTX binding to VR in spinal cord of several species, including humans
| Species | Kd | Cooperativity Index | Capsaicin | Capsazepine |
|---|---|---|---|---|
| pM | Ki, μM | Ki, μM | ||
| High (pM)-affinity binding | ||||
| Rat (1–3) | 13–31 | 1.9–2.3 | 0.3–5.0 | 3.3–4.0 |
| Mouse (4) | 18 | 2.1 | N.D. | N.D. |
| Pig (5) | 88 | 2.3 | 9.7 | 6.8 |
| Moderate (nM)-affinity binding | ||||
| Human (6, 7) | 0.9–11.0 | 1.1–1.4 | 0.3–1.1 | 0.06–0.3 |
| Monkey (8) | 3,000 | 1.0 | 17.0 | 3.0 |
| Guinea pig (7) | 5,000 | 1.0 | 0.5 | 0.1 |
N.D., not determined. References indicated in parentheses: (1)Ács et al., 1994a; (2) Szallasi and Blumberg, 1993a; (3) Szallasi et al., 1993b; (4) Szallasi, 1994; (5) Ács and Blumberg, 1994; (6) Ács et al., 1994b; (7) Szallasi and Goso, 1994; (8) T. Biró and P.M. Blumberg, unpublished observations.