TABLE 4

Stoichiometry of CRIP1a and CB1 receptor expression in N18TG2 and N18TG2-CRIP1a cells

Membranes prepared from the indicated cell line were incubated with varying concentrations of [3H]CP55,940, as described in Materials and Methods. Bmax and KD values were derived from nonlinear regression analysis of the saturation binding curves. CRIP1a protein values were determined by quantitative immunoblot using purified CRIP1a as an internal standard, as described in Materials and Methods. Data are mean values ± S.E.M. (n = 4–8).

Tissue SourceCB1BmaxCB1KDCRIP1aMolar Ratio CRIP1a/CB1
pmol/mgnMpmol/mg
Control N18TG20.298 ± 0.0392.35 ± 0.330.56 ± 0.071.87 ± 0.23
N18-CRIP1a-OX10.277 ± 0.0333.02 ± 0.711.35 ± 0.16**4.87 ± 0.59**
N18-CRIP1a-OX50.270 ± 0.0504.22 ± 0.961.28 ± 0.09**4.74 ± 0.34**
N18-CRIP1a-KD0.320 ± 0.0452.49 ± 0.38N.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.