GRM3 and Addictive alcohol use: The efficacy of NAAG peptidase inhibition in reversing the effects of ethanol treatment (Figs. 3, 4, 5, 6) is consistent with the view that group II receptors, particularly mGluR3, are among the more promising targets for the development of drugs to treat alcohol addiction [76–78] Heterotropic group II glutamate receptor agonists reduce drug seeking, conditioned place preference and stress-induced reinstatement in animal models of alcohol addiction [76, 79, 80].