Table 1.

Effects of cannabinoids on the internalization of CB₁ receptors in F-11 cells

Treatment	F-11 surface labeling (Cy3)	F-11 intracellular labeling (Alexa 488)
(+)-WIN55212 (30)	0.39  ± 0.071-160	1.73  ± 0.33*
(+)-WIN-55212/SR141716A (29)	0.77  ± 0.13	0.66  ± 0.09
(−)-WIN55212 (28)	0.77  ± 0.11	1.18  ± 0.19
Vehicle (30)	1.00  ± 0.10	1.00  ± 0.11
SR141716A (31)	1.12  ± 0.33	0.96  ± 0.14

The Cy³-conjugated secondary antibody labeled receptors remained on the cell surface after cannabinoid incubation, whereas the Alexa 488-conjugated secondary antibody-labeled receptors were internalized. Values are mean (±SEM) fluorescence intensity levels measured from defined intracellular and plasma membrane regions and normalized relative to vehicle controls. The number of cells are given in parentheses and were taken from four independent experiments. Cannabinoids and related compounds were applied at 1 μm. Multiple comparisons between groups within each column was made with ANOVA with Dunnett's post hoc test comparing results with those for vehicle alone.

^*p < 0.05;

F1-160: p < 0.01.