Peripheral Administration of Tiqs and Intake of an Alcoholic Beverage

Abstract

In 1970, two findings indicated that a metabolite of ethanol (E) could combine with certain neurotransmitters to produce potential opioidergic products [1,2]. The idea is that acetylaldehyde (the first metabolic product of E) in the presence of either phenylethylamine, dopamine, norepinephrine or epinephrine yields a class of compounds called tetrahydroisoquinolines (TIQs). Subsequently, it was demonstrated that the central administration of a TIQ increased intake of E among rats [3,4,5]. Although a critical site of action of these putative metabolites of E must be in brain, the question remains:What effects do these agents have on intake of E when administered peripherally? Therefore, we tested the effects of 3 TIQs on rats’ intake of a sweetened alcoholic beverage. The 3 TIQs tested were:(a) 1,2,3,4-tetrahydroisoquinoline (1,2,3,4-TIQ); (b) tetrahydropapaveroline (THP); and (c) 1-salsolinol (SAL).