Parameters for the interaction of brucine with [3H]NMS and ACh at m1—m5 muscarinic receptors
| Subtype | Assay | Log affinity | Cooperativity | n | ||
|---|---|---|---|---|---|---|
| Unoccupied receptor | [3H]NMS-occupied receptor | [3H]NMS | ACh | |||
| m1 | Nonequilibrium | 4.73 ± 0.02 | 4.68 ± 0.05 | 0.87 ± 0.08 | 3 | |
| Equilibrium | 4.58 ± 0.05 | 4.54 ± 0.07 | 0.91 ± 0.04 | 1.60 ± 0.103-a | 5 | |
| m2 | Nonequilibrium | 4.25 ± 0.06 | 4.53 ± 0.04 | 1.91 ± 0.04 | 3 | |
| Equilibrium | 4.53 ± 0.04 | 4.74 ± 0.05 | 1.59 ± 0.06 | 0.28 ± 0.05 | 4 | |
| m3 | Nonequilibrium | 3.70 ± 0.05 | 3.51 ± 0.04 | 0.52 ± 0.01 | 2 | |
| Equilibrium | 3.52 ± 0.08 | 2.92 ± 0.13 | 0.25 ± 0.03 | 0.52 ± 0.10 | 4 | |
| m4 | Nonequilibrium | 4.63 ± 0.05 | 4.54 ± 0.03 | 0.84 ± 0.09 | 4 | |
| Equilibrium | 4.77 ± 0.15 | 4.49 ± 0.13 | 0.54 ± 0.06 | 0.33 ± 0.11 | 4 | |
| m5 | Nonequilibrium | |||||
| Equilibrium | 4.31 ± 0.06 | 3.29 ± 0.02 | 0.10 ± 0.02 | 0.07 ± 0.01 | 2 | |
↵3-a Significantly different from 1, p < 0.005, two-tailed t test.