Effects of tetrahydropapaveroline in the nucleus accumbens and the ventral tegmental area on ethanol preference in the rat.

Numerous studies have attempted to identify sites of action in brain that are sensitive to the dopamine-aldehyde condensation product, tetrahydropapaveroline (THP). Recent studies performed by Myers and his co-workers have uncovered diverse sites of action in the brain. The present experiments were based on the hypothesis that the dopamine-aldehyde condensation products would be most reactive at those synapses that were dominated by the parent amine. To test this hypothesis, rats were implanted with bilateral cerebral cannulae in those brain regions that define the rostral-caudal aspects of two major dopaminergic systems: the mesolimbic system and the nigrostriatal system. Following surgery, rats were given single, bilateral injections of 1.0 microgram THP. The results suggest that a single injection of THP tends to augment the rat's preference for ethanol, when THP is placed in regions of the brain that correspond to the mesocorticolimbic system which in this study included certain aspects of the posterior hypothalamus. THP did not change the rat's preference for ethanol when the compound was injected into the nigrostriatal system.