Tiapride prevents the aversive but not the rewarding effect induced by parabrachial electrical stimulation in a place preference task.

The parabrachial complex has been related to the processing of both rewarding and aversive signals. This pontine area is activated after the gastrointestinal administration of rewarding nutrients, in taste aversion learning, and in response to the reinforcing and aversive effects of some drugs of abuse. Electrical stimulation of this region can induce, in different animals, preference or aversion behaviors towards a place in a rectangular three-chamber maze task. This study examined the effect of tiapride, a D2/D3 receptor antagonist, on the aversive or rewarding effects induced by electrical stimulation of the external lateral parabrachial subnucleus (NLPBe). As previously observed, administration of tiapride interrupted the aversive effect induced by NLPBe electrical stimulation. However, in contrast to the effects of dopamine antagonists on other rewarding systems, tiapride did not impair the place preference induced by NLPBe stimulation, an activation effect that is subject to tolerance. Tiapride administration also appeared to have no effect on the horizontal motor activity (crossings) of the electrically stimulated animals. We discuss the specific relevance of parabrachial reward with respect to other reinforcing brain components or systems, especially in relation to the preference effect of drugs of abuse, such as opiates, after dopamine antagonist administration.