Following re-training with 1 mg/kg THC, the dose-effect curve for THC-lever responding was shifted to the left, with an ED50 value of 0.20 mg/kg (95% CI: 0.089 – 0.43 mg/kg) [Fig. 3, panel B]. Again, URB597 failed to produce significant increases in responding on the THC-associated lever (Fig. 3, panel B) and did not affect overall response rates (Fig. 3, panel D). As previously, 10 mg/kg THC continued to produce significant decreases in response rates after rats were re-trained to discriminate 1 mg/kg THC from vehicle [F(5,25)=14.43, P<0.05] (Fig. 3, panel D).
