Effects of the cannabinoid antagonists AM281 and AM630 on deprivation-induced intake in Lewis rats.

Male Lewis rats (two groups of 10) received intracerebroventricular injections of either AM 630 (vehicle, 2.5, 5, 10 and 20 microg) or AM 281 (vehicle, 5, 10, 20 and 40 microg) following overnight food deprivation. The CB2 antagonist AM 630 failed to block deprivation-induced intake at 0.5, 1, 2, 4 and 6 h. The CB1 antagonist AM 281 significantly blocked intake following 20 microg (1 h) and 40 microg (1, 2, 4 and 6 h). Results are discussed with respect to cannabinoid receptor systems' involvement in ingestion and the differential pharmacological profiles of AM 630 and AM 281.