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.

Gallamine6.08 ± 0.16−3#34.12 ± 0.21*−3#4
Strychnine5.13 ± 0.05−3#33.55 ± 0.36*−3#4
Brucine5.42 ± 0.14−3#34.21 ± 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.