FIGURE 3.

Comparison of CB1R desensitization produced by chronic SCB treatment. CHO-hCB1 cells were exposed to vehicle (filled squares) or a receptor saturating concentration of Δ⁹-THC (1 μM, filled circles) or AB-PINACA (1 μM, open squares) for 24 h. Following chronic exposure, cells were washed extensively to remove residual drug and the ability of increasing concentrations (10^-10 to 10^-5) CP-55,940 to modulate adenylyl cyclase activity was examined. Data points presented are the mean ± SEM of basal intracellular cAMP in the presence of CP-55,940 following chronic treatment with the respective vehicle or drug. Curve fitting of concentration-effect curves via non-linear regression was employed to determine the IC₅₀ (measure of potency) and I_max (measure of efficacy) for adenylyl cyclase modulation by CP-55,940 following chronic exposure to vehicle or each agonist. The mean ± SEM and statistical comparison of IC₅₀ and I_max values calculated for each SCB are presented and discussed in the Results section.