TABLE 1

Comparison of ligand binding parameters for WT and C6.47(355) mutant human CB1 receptors Binding parameters were determined in cellular membranes prepared from WT and mutant CB1 transfected CHO cells as described under Materials and Methods. The binding affinities shown represent the mean ± S.E.M. of at least three independent determinations each performed in quadruplicate.

	[³H]WIN55212–2		[³H]CP55940		K_i vs. [³H]CP55940
	K_d	B_max	K_d	B_max	AM841	AM4043	AM4056	Δ⁹-THC
	nM	pmol / g	nM	pmol / g	nM
WT	18.3 ± 0.99	1030 ± 90	6.7 ± 0.34	1069 ± 73	9.05 ± 2.06^a	3.99 ± 0.87	2.99 ± 0.47	89.9 ± 0.97
C6.47(355)S	22.5 ± 1.03	1040 ± 27	9.0 ± 1.30	1043 ± 40	10.46 ± 0.88	6.07 ± 0.54	9.88 ± 1.12	103.4 ± 16.4
C6.47(355)A	19.7 ± 0.85	1069 ± 34	7.5 ± 0.25	1029 ± 27	11.32 ± 0.29	5.42 ± 0.22	5.97 ± 0.94	51.3 ± 2.45^†
C6.47(355)L	20.2 ± 0.82	1013 ± 82	20.2 ± 1.48^*	1012 ± 84	58.09 ± 11.69^**	40.50 ± 1.30^*	38.08 ± 4.98^*	34.2 ± 6.69^†

↵ a Apparent K_i value
↵* P < 0.0001, analysis of variance
↵** P < 0.0007, analysis of variance
↵† P < 0.05, Bonferroni's post hoc test