TABLE 1

Stoichiometry of CRIP_1a and CB₁ receptor expression in CB₁-HEK and CB₁-HEK–CRIP_1a cells compared with rat cerebellum

Membranes prepared from the indicated tissue sources were incubated with varying concentrations of [³H]SR141716A, as described in Materials and Methods. B_max and K_D values were derived from nonlinear regression analysis of the saturation binding curves. CRIP_1a protein values were determined by quantitative immunoblot of the indicated tissue source, using purified CRIP_1a as an internal standard, as described in Materials and Methods. Data are mean values ± S.E.M. (n = 4–6)

Tissue Source	CB₁B_max	CB₁K_D	CRIP_1a	Molar Ratio CRIP_1a/CB₁
	pmol/mg	nM	pmol/mg
CB₁-HEK	1.34 ± 0.12	1.45 ± 0.19	0.56 ± 0.13	0.42 ± 0.09
CB₁-HEK-CRIP_1a	1.17 ± 0.13	1.63 ± 0.35	8.20 ± 0.64^**	7.01 ± 0.55^**
Rat cerebellum	3.76 ± 0.31	0.49 ± 0.04	115 ± 12.2	32.02 ± 4.39

↵** P < 0.01 different from corresponding value in CB₁-HEK cells by Student’s t test with Welch’s correction (note: values from cerebellum were not included in the analysis).