Parameter estimates from [3H]NMS off-rate assays Parameters for the inhibition of [3H]NMS dissociation measured at a single time were derived from fitting three assays such as those shown in Fig. 4 to a logistic function. pEC50 is —log of the concentration causing 50% of the maximal effect; according to the allosteric model it corresponds to the log affinity of thiochrome for the [3H]NMS-occupied receptor. Emax is the dissociation rate constant of [3H]NMS, expressed as a percentage of control, in the presence of a saturating concentration of thiochrome. Predicted indicates the pEC50 value predicted by multiplying the mean estimates of affinity and the cooperativity with [3H]NMS from the equilibrium assays summarized in Table 1.
| Subtype | pEC50 | Slope | Emax | Predicted |
|---|---|---|---|---|
| % | ||||
| M1 | 3.40 ± 0.04 | 1.7 ± 0.1 | 0.1 ± 0.1 | 3.94 |
| M2 | 3.52 ± 0.06 | 1.6 ± 0.1 | 1.7 ± 1.7 | 3.87 |
| M3 | 3.17 ± 0.06 | 1.7 ± 0.1 | 0.0 ± 0.0 | 4.23 |
| M4 | 3.59 ± 0.03 | 1.5 ± 0.1 | 0.6 ± 0.6 | 3.77 |
| M5 | 2.81 ± 0.17 | 1.3 ± 0.3 | 15 ± 15 |