Table 1

Effects of genetic modifications on the binding properties of muscarinic M₃ receptors

	[³H]NMS		Gallamine		Alcuronium
	K_d	k_off	pK_diss	pK_A	α	pK_diss	pK_A	α
	nM	min⁻¹	M			M
Wild-type M₃	0.29 ± 0.006	0.05 ± 0	3.91 ± 0.02	4.7 ± 0.08	4.3 ± 0.6	3.70 ± 0.04	3.9 ± 0.09	2.6 ± 0.3
Wild-type M₂	0.75 ± 0.05^1-150	0.34 ± 0.02^1-150	4.80 ± 0.19^1-150	6.4 ± 0.03^1-150	11 ± 0.4^1-150	6.90 ± 0.10^1-150	6.1 ± 0.2^1-150	0.3 ± 0.05^1-150
Modifications in o1 of M₃
R133G	0.49	0.07 ± 0.002^1-150	4.44 ± 0.08^1-150	NM	Close to 1^1-159	3.71 ± 0.18	3.9 ± 0.03	1.8 ± 0.2
	(0.50; 0.48)
Modifications in o2 of M₃
K213T	0.33	0.05 ± 0.002	4.01 ± 0.01	4.5 ± 0.18	2.9 ± 0.4	3.79 ± 0.05	4.1 ± 0.08	1.6 ± 0.03
	(0.32; 0.34)
P217D	0.31	0.06 ± 0.002^1-150	4.30 ± 0.04^1-150	4.8 ± 0.01	4.2 ± 1.0	4.03 ± 0.15	4.1 ± 0.05	2.4 ± 0.5
	(0.31; 0.31)
P217D ⁺P218E	0.39	0.06 ± 0.002^1-150	4.23 ± 0.06^1-150	4.6 ± 0.06	4.0 ± 0.8	3.95 ± 0.02^1-150	4.2 ± 0.03	2.1 ± 0.4
	(0.39; 0.39)
o2M₂	0.27 ± 0.03	0.06 ± 0.003^1-150	4.75 ± 0.04^1-150	5.8 ± 0.05^1-150	4.8 ± 0.5	4.72 ± 0.01^1-150	4.8 ± 0.04^1-150	3.1 ± 0.8
Modifications in o3 of M₃
K523N	0.65	0.15 ± 0.003^1-150	4.54 ± 0.003^1-150	6.1 ± 0.06^1-150	16.0 ± 1.9^1-150	4.69 ± 0.04^1-150	4.7 ± 0.20^1-150	1.8 ± 0.3
	(0.65; 0.66)
KFN	0.49 ± 0.11	0.22 ± 0.02^1-150	4.12 ± 0.07^1-150	6.4 ± 0.17^1-150	46.5 ± 12.0^1-150	4.72 ± 0.12^1-150	NM	Close to 1^1-159
DSKFN	0.74 ± 0.12^1-150	0.21 ± 0.01^1-150	4.21 ± 0.04^1-150	6.3 ± 0.11^1-150	25.1 ± 3.8^1-150	4.67 ± 0.07^1-150	4.4 ± 0.12^1-150	0.3 ± 0.03^1-150

Data are means ± S.E.M. of three to nine experiments; individual results have been shown where n < 3.

↵1-150 , Significantly different from wild-type M₃(p < 0.05 by Student's two-tailed t test);
↵1-159 , Although clearly different from wild-type M₃, significance could not be evaluated numerically because of flat binding curves.
NM, not measurable because the binding curves were flat.