Differences in basal cannabinoid CB1 receptor function in selective brain areas and vulnerability to voluntary alcohol consumption in fawn hooded and Wistar rats

Aim: To specify the functional activity of cannabinoid CB1 receptor in alcohol-preferring Fawn Hooded and alcohol nonpreferring Wistar rats under naive conditions. Method: Cannabinoid CB1 (WIN-55,212)-stimulated [S-35]-GTPgammas binding autoradiography, and cannabinoid CB1 receptor gene expression were measured in rats of both strains that received only water. Results: Cannabinoid CB1 receptor stimulated [S-35]-GTPgammas binding was significantly lower in cingulate cortex (Cg), caudate-putamen (CPu), nucleus accumbens (Acc), ventromedial hypothalamic nucleus (VMN), amygdaloid area (AMG), fields (CA1, CA3) of the hippocampus and dentate gyrus (DG) in Fawn Hooded than in Wistar rats, whereas no differences were found either in substantia nigra pars reticulata (SNr) nor CA2 field of the hippocampus. In addition, cannabinoid CB1 receptor gene expression was lower in Cg, CPu, VMN and CA3 field of the hippocampus in Fawn Hooded than in Wistar rats. Conclusions: We speculate that lower cannabinoid function appears to be related to greater vulnerability to alcohol consumption. Cannabinoid CB1 receptor may represent a key target in the treatment of alcohol dependence.