TABLE 2

Empirical inhibition binding parameters for ACh, McN-A-343, AC-42, and 77-LH-28-1 against [3H]NMS at the M2-WT and M2-EDGE-YT mAChRs Values represent the mean ± S.E.M. from three experiments performed in triplicate. pKB(High) and pKB(Low) are the negative logarithms of the apparent high- and low-affinity equilibrium dissociation constants, respectively, FH is the fraction of the receptors exhibiting high-affinity binding, and nH is the Hill slope.

M2-WT M2-EDGE-YT
pKB(High) pKB(Low)FHnH pKB(High) pKB(Low)FH nH
ACh 7.08 ± 0.13 5.61 ± 0.17 0.59 ± 0.07 0.62 ± 0.06# 6.40 ± 0.12* 5.10 ± 0.16 0.59 ± 0.07 0.69 ± 0.08#
McN-A-343 6.14 ± 0.16 4.89 ± 0.08 0.15 ± 0.07 0.79 ± 0.07# 6.14 ± 0.16 4.89 ± 0.08 0.51 ± 0.08* 0.67 ± 0.09#
AC-42 5.42 ± 0.06 0.98 ± 0.12 5.86 ± 0.05* 0.88 ± 0.08
77-LH-28-1 6.23 ± 0.03 0.91 ± 0.06 7.33 ± 0.11 5.73 ± 0.12 0.55 ± 0.06 0.82 ± 0.04#
  • # Significantly different (P < 0.05) from 1.

  • * Significantly different (P < 0.05) from the corresponding control value within the same treatment group.