TABLE 4.

Stoichiometry of CRIP_1a and CB₁ receptor expression in N18TG2 and N18TG2-CRIP_1a cells

Membranes prepared from the indicated cell line were incubated with varying concentrations of [³H]CP55,940, 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 using purified CRIP_1a as an internal standard, as described in Materials and Methods. Data are mean values ± S.E.M. (n = 4–8).

Tissue Source	CB1 Bmax	CB1 KD	CRIP1a	Molar Ratio CRIP1a/CB1
	pmol/mg	nM	pmol/mg
Control N18TG2	0.298 ± 0.039	2.35 ± 0.33	0.56 ± 0.07	1.87 ± 0.23
N18-CRIP1a-OX1	0.277 ± 0.033	3.02 ± 0.71	1.35 ± 0.16**	4.87 ± 0.59**
N18-CRIP1a-OX5	0.270 ± 0.050	4.22 ± 0.96	1.28 ± 0.09**	4.74 ± 0.34**
N18-CRIP1a-KD	0.320 ± 0.045	2.49 ± 0.38	N.D.	N.D.

^**P < 0.01 different from corresponding value in control N18TG2 cells by one-way ANOVA with posthoc Dunnett’s test. N.D., not determined.