The endogenous cannabinoid anandamide shares discriminative stimulus effects with ∆(9)-tetrahydrocannabinol in fatty acid amide hydrolase knockout mice.

Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, PO BOX 980613, Richmond, VA 23298-0613, United States.
European journal of pharmacology (Impact Factor: 2.59). 02/2011; 656(1-3):63-7. DOI: 10.1016/j.ejphar.2011.01.056
Source: PubMed

ABSTRACT The endogenous cannabinoid system has been noted for its therapeutic potential, as well as the psychoactivity of cannabinoids such as Δ9-tetrahydrocannabinol (THC). However, less is known about the psychoactivity of anandamide (AEA), an endocannabinoid ligand. Thus, the goals of this study were to establish AEA as a discriminative stimulus in transgenic mice lacking fatty acid amide hydrolase (i.e., FAAH -/- mice unable to rapidly metabolize AEA), evaluate whether THC or oleamide, a fatty acid amide, produced AEA-like responding, and assess for CB(1) mediation of AEA's discriminative stimulus. Mice readily discriminated between 6mg/kg AEA and vehicle in a two-lever drug discrimination task. AEA dose-dependently generalized to itself. THC elicited full AEA-like responding, whereas oleamide failed to substitute. The CB(1) antagonist rimonabant attenuated AEA- and THC-induced AEA-appropriate responding, demonstrating CB(1) mediation of AEA's discriminative stimulus. These findings suggest that, in the absence of FAAH, AEA produces intoxication comparable to THC, and consequently to marijuana.

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