Affinity of cholinergic agonists and antagonists
| The Kd and Ki values were derived from [3H]Epi saturation and competition binding studies of immunoimmobilized native β2-, β4-, and α6-containing receptors prepared as described under Materials and Methods. The curves obtained from three separate experiments were fitted using a nonlinear least-squares analysis program and the F test as described by Vailati et al. (1999). The numbers in parentheses represent the percentage of coefficient of variation. | |||
|---|---|---|---|
| Ki | |||
| β2-Containing Receptors (α6-Depleted) | β4-Containing Receptors (α6-Depleted) | α6-Containing Receptorsa | |
| nM | |||
| Acetylcholine | 123 (49) | 72 (17) | 76 (26) |
| Nicotine | 131 (56) | 98 (24) | 20 (31) |
| α-Conotoxin MII | >2000 | >2000 | 66 (24) |
| Dihydro-β-erythroidine | 502 (58) | 201 (49) | 2800 (13) |
| d-Tubocurarine | 3085 (52) | 6900 (25) | 7700 (18) |
| MG624 | 12,000 (35) | 9200 (25) | 4520 (26) |
| Decamethonium | 41,000 (24) | 38,570 (28) | 35,900 (16) |
| Hexamethonium | 990,000 (18) | 373,000 (33) | 349,000 (18) |
| [3H]epibatidine (Kd, pM) | 27 (20) | 26 (16) | 35 (18) |
↵ a From Vailati et al., 1999.