Noradrenergic mediation of the positive reinforcing properties of ethanol: I. Suppression of ethanol consumption in laboratory rats following dopamine-beta-hydroxylase inhibition

Abstract

Ethanol-drinking rats were injected with the dopamine-beta-hydroxylase inhibitor FLA-57, prior to free-choice presentations of ethanol and water either for 5 alternate days (25 or 40 mg/kg i.p.) or for 5 consecutive days (45 mg/kg i.p.). In all cases, the FLA-57 treated animals markedly attenuated ethanol consumption while vehicle-injected controls showed no change from baseline. In the post-injection period ethanol intake gradually returned to baseline levels. Biochemical assays revealed that whole brain norepinephrine levels following injection of FLA-57 (15-60 mg/kg i.p.) were significantly depressed while dopamine and serotonin levels were slightly increased. It is suggested that norepinephrine may be involved in the mediation of the positive reinforcing properties of ethanol regulating its self-administration.