Rimonabant (National Institute on Drug Abuse, Rockville, MD), Δ9-THC (National Institute on Drug Abuse, Rockville, MD), and CP-55,940 (Pfizer, Groton, CT) were dissolved in a 1:1 mixture of absolute ethanol and alkamuls-620 (Rhone-Poulenc, Princeton, NJ), and diluted with saline in a final ratio of 1:1:18 (ethanol/alkamuls/saline). The vehicle consisted of the 1:1:18 (ethanol/alkamuls/saline) solution. All systemic injections were given through the i.p. route of administration in a volume of 1 ml/kg. All intracerebral injections were given bilaterally in an injection volume of 0.5 μl per side.
