TABLE 2

Parameters characterizing the interaction of orthosteric ligands with the equilibrium binding of [³H]dimethyl-W84 and [³H]NMS at M₂ receptors

The data are mean values ± S.E.M. of three to seven independent experiments. For details see text.

	[³H]dimethyl-W84		[³H]NMS		logK_X,orthoster - logK_i,orthoster
Orthosteric agent	logK_X,orthoster	α	logK_i,orthoster	n_H	logK_X,orthoster - logK_i,orthoster
(+)-Dexetimide	9.03±0.07	0.02±0.03	8.93±0.19	1.07±0.08	0.10
NMS	9.40±0.12	0.19±0.03	9.37±0.16^a	1.01±0.05	0.03
(-)-Scopolamine	8.63±0.12	0.08±0.01	8.59±0.19	1.01±0.08	0.04
Atropine	8.36±0.07	0.20±0.02	8.66±0.20	1.01±0.08	-0.30
AF-DX 384	8.03±0.06	0.09±0.02	8.09±0.26	0.96±0.13	-0.06
NBS	6.77±0.07	0.07±0.02	6.78±0.20	1.04±0.08	-0.01
(-)-Levetimide	5.18±0.04^b	—^b	5.32±0.17	1.02±0.08	N.D.