Competitor | [3H]NMS | [Xanomeline] | pKH3-a | pKL3-b | pKI3-c | nH3-d |
---|---|---|---|---|---|---|
nm | nm | |||||
CCh | 0.2 | 5.25 ± 0.15 (40.8%) | 3.75 ± 0.13 | 0.56 ± 0.083-e | ||
Xanomeline | 0.2 | 7.51 ± 0.03 | 0.92 ± 0.11 | |||
2 | 7.38 ± 0.09 | 1.02 ± 0.14 | ||||
Atropine | 0.2 | 8.50 ± 0.15 | 0.94 ± 0.08 | |||
0.4 | 30 | 8.75 ± 0.07 | 0.97 ± 0.08 | |||
0.6 | 100 | 8.64 ± 0.07 | 0.94 ± 0.07 |
Competition binding experiments were conducted for 1 hr at 37° in HEPES buffer as outlined in the text. Parameters derived from nonlinear regression analysis are presented as the mean ± standard error of three determinations conducted in triplicate.
↵3-a Negative logarithm of the dissociation constant for the high affinity agonist binding site; percentage of binding sites is given in parentheses.
↵3-b Negative logarithm of the dissociation constant for the low affinity agonist binding site.
↵3-c Negative logarithm of the dissociation constant for binding to a single affinity site, calculated as described in Experimental Procedures.
↵3-d Logistic slope factor.
↵3-e Significantly different from unity.