Table 7.

Effects of alcuronium and gallamine on ACh-stimulated [³⁵S]GTPγS binding at M₃ receptors.

	40 nM [3H]ACh binding			[35S]GTPγS binding
	kobs [min-1]	Beq [fmol/mg prot.]	kobs [min-1]	Beq [fmol/μg prot.]	pEC50	EMAX [fold over basal]
Control	1.28 ± 0.06	357 ± 17	0.0579 ± 0.0013	530 ± 37	5.18 ± 0.03	2.94 ± 0.12
+ 1 μM alcuronium	1.00 ± 0.02*	262 ± 10*	0. 0509 ± 0.0017*	496 ± 33	5.03 ± 0.02*	2.90 ± 0.14
+ 10 μM alcuronium	0.888 ± 0.012*	199 ± 12*	0.0481 ± 0.0021*	428 ± 39*	4.82 ± 0.02*	2.87 ± 0.12
+ 1 μM gallamine	1.06 ± 0.02*	246 ± 10*	0.0525 ± 0.0015*	479 ± 29	5.01 ± 0.04*	2.83 ± 0.12
+ 10 μM gallamine	0.783 ± 0.009*	191 ± 8*	0.0492 ± 0.0015*	442 ± 27*	4.82 ± 0.01*	2.73 ± 0.15

Values of observed rates of association (k_obs) and equilibrium binding (B_eq) of 40 nM [³H]ACh with M₃ receptors were obtained by fitting Eq. 6 to data in Figure 10 (top). Values of k_obs and B_eq of 200 pM [³⁵S]GTPγS with M₃ receptors were obtained by fitting Eq. 6 to data in Figure 10 (middle). Negative logarithms of half effective concentrations (pEC₅₀) and maximum stimulatory effect (E_MAX) of acetylcholine on [³⁵S]GTPγS binding in the absence or presence of the indicated concentrations of alcuronium or gallamine were obtained by fitting Eq. 5 to the data in Figure 10 (bottom). Values are means ± SE of fits to 3 to 6 independent experiments performed in quadruplicates. *P < 0.05; significantly different from control (ACh alone) by ANOVA and Tukey-Kramer post-test.