Abstract
Conditioned taste aversions induced by pairing the consumption of saccharin with an amphetamine injection are attenuated in rats with depletion of central catecholamines caused by intraventricular administration of 6-hydroxydopamine (6-OHDA). The hypothesis that dopamine (DA) depletion is responsible for this effect was tested. The reduction in conditioning caused by intraventricular 6-OHDA could not be duplicated either with injections of 6-OHDA into the substantia nigra (Experiment 1) or with intraventricular 6-OHDA injections in animals pretreated with desmethylimipramine (Experiment 2). Both treatments, however, produced large depletions of telencephalic DA. 6-Hydroxydopa infusions caused a preferential loss of telencephalic norepinephrine (NE) but also failed to alter taste aversion learning. It is concluded that the effect of intraventricular 6-OHDA on amphetamine-induced aversions was the result of depletion of both NE and DA. In a third experiment the generality of the effect was examined by pairing saccharin consumption with injections of the amphetamine congener fenfluramine. Depletion of both NE and DA failed to alter fenfluramine-induced aversions. Infusion of 6-OHDA into the substantia nigra, however, retarded the extinction of such an aversion. Evidence is discussed for a peripheral site of action for fenfluramine in the conditioned aversion paradigm.
Published Version
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