Nicotine [(-)-nicotine hydrogen tartrate] (Sigma, USA) was dissolved in saline (pH corrected to 7.0) and injected s.c. or i.v. (-)-Cocaine HCl (RTI international, USA) and injected i.v. The PPAR-α agonist methOEA (methyl oleoylethanolamide; donated by Dr. Daniele Piomelli, University of California, Irvine) was dissolved in 2% Tween80, 2% ethanol, and sterile water. The PPAR-α agonist WY14643 ([[4-Chloro-6-[(2,3-dimethylphenyl)amino]-2-pyrimidinyl] thio]acetic acid; Tocris, USA) and PPAR-α antagonist MK886 (1-[(4-Chlorophenyl)methyl]-3-[(1,1-dimethylethyl)thio]-a,a-dimethyl-5-(1-methylethyl)-1H-Indole-2-propanoic acid; Tocris, USA) were dissolved in 2-4% Tween 80, 30% DMSO, and sterile water. MethOEA, WY14643 and MK886 were injected i.p. (1 ml/kg) in rats and i.m. (0.3 ml/kg) in monkeys, except for electrophysiology, where methOEA was injected i.v. Dose selection was based on previous studies using WY14643 (8,16,17), methOEA (KDS5104) (18) and MK886 (8,16).
