DELTA(9)-TETRAHYDROCANNABINOL, BUT NOT THE ENDOGENOUS CANNABINOID RECEPTOR-LIGAND ANANDAMIDE, PRODUCES CONDITIONED PLACE AVOIDANCE

Although exogenous cannabinoid ligands such as Delta(9)-tetrahydrocann abinol (THC) have been implicated in reward-related learning and avers ion, the hedonic effects of the endogenous cannabinoid agonist anandam ide (arachidonylethanolamide) have never been assessed. Thus, the effe cts of anandamide were tested in a place conditioning task. Male Wista r rats received THC (0.0-8.0 mg/kg) or anandamide (0.0-16.0 mg/kg) dur ing conditioning sessions. The half-life of anandamide was increased b y pretreatment with the protease inhibitor phenylmethylsulfonyl fluori de (2.0 mg/kg). A significant place aversion was found at the 1.0 and 1.5 mg/kg doses of THC. No significant place conditioning effects were found with anandamide. Locomotor activity during conditioning was sig nificantly decreased by the 1.0, 1.5, 2.0 and 4.0 mg/kg doses of THC a s well as the 8.0 and 16.0 mg/kg doses of anandamide. These results fa il to implicate the endogenous cannabinoid anandamide in reward-relate d learning or aversion.