Unless specified, all chemicals were obtained from Sigma-Aldrich (St Louis, MO, USA) or Fisher Chemicals (Fair Lawn, NJ, USA). AM3506 was synthesized at Northeastern University as described.19,20 SR141716 (Rimonabant) was provided by the National Institute on Drug Abuse Drug Supply program. Both drugs were dissolved in dimethylsulfoxide and aliquoted for storage at −80 °C. For in vivo administration, AM3506 was suspended in a 9:1 saline/dimethylsulfoxide solution and SR141716 was suspended in an 18:1:1 saline/Tween/dimethylsulfoxide solution. For systemic treatment, drugs were injected intraperitoneally in a volume of 10 ml/kg body weight. For intra-amygdala microinfusions, drugs were suspended as described above and infused, via bilateral 33-G injectors (Plastics One, Roanoke, VA, USA) projecting 1 mm past the guide cannula, in a volume of 0.5 μl per hemisphere over 2 min using a syringe pump (Harvard Apparatus PHD 22/2000, Holliston, MA, USA). Injectors were left in place for a further 3 min to allow diffusion into the tissue.
