Dopaminergic mediation of reward: evidence gained using a natural reinforcer in a behavioral contrast paradigm.

Previous studies suggest a dopaminergic basis for the apparent reward properties of self-stimulation of certain brain areas with electrical current. The data of this present study indicate that there may be a dopaminergic role in the perceived hedonic quality of natural reinforcers. Using a classical behavioral contrast paradigm, we observed in rats that the perceived reward of a saccharin solution was decreased by haloperidol and increased by apomorphine, in doses that did not cause non-specific performance effects.