Affinity (pKB) and functional cooperativity with ACh (logαβACh) estimates of the prototypical NAMs in [35S]GTPγS binding accumulation assay at the wild-type and N410K+T423K M2 mAChRs
Values represent the mean ± S.E. from at least three experiments performed in duplicate.
| WT | N410K+T423K | |||||
|---|---|---|---|---|---|---|
| pKBa | LogαβAChb | nc | pKBa | LogαβAChb | n | |
| Gallamine | 6.08 ± 0.16 | −3# | 3 | 4.12 ± 0.21* | −3# | 4 |
| Strychnine | 5.13 ± 0.05 | −3# | 3 | 3.55 ± 0.36* | −3# | 4 |
| Brucine | 5.42 ± 0.14 | −3# | 3 | 4.21 ± 0.22* | −3# | 4 |
↵a Negative logarithm of the allosteric modulator equilibrium dissociation constant.
↵b Logarithm of the functional cooperativity for the interaction between the modulator and ACh; in all instances, the interaction was indistinguishable from competition (F-test), indicative of very high negative cooperativity (αβ → 0), and thus cooperativity values were constrained to an arbitrarily low value, #.
↵c Number of experiments performed.
↵* Significantly different from the corresponding value at the wild type (P < 0.05), Student’s t test.
↵# Arbitrarily low value.