The objective of this study was to examine if (R)-methanandamide, a metabolically stable chiral analog of the endogenous ligand anandamide, is a cannabimimetic with a lower efficacy than delta9-THC. Employing a two-lever choice drug discrimination procedure, rats were trained to discriminate between 1.8, 3.0, or 5.6 mg/kg delta9-tetrahydrocannabinol (delta9-THC) and vehicle. Different training...