Microinjections of SCH23390 and haloperidol into striatal subregions differentially affect water intake in the rat

The nigrostriatal dopamine neurotransmission system is known to mediate various types of functional behaviors. Systemic administration of dopamine antagonists impairs drinking behavior induced by different dipsogenic agents. The present study was designed to further characterize the potential neural loci for hypodipsia under dopamine receptor blockade of the striatum via local administrations of SCH23390 and haloperidol. Water deprived rats were bilaterally implanted with cannula aimed at either the dorsomedial or ventrolateral striatum (DMS or VLS). Water intake was measured for 30 min after the intrastriatal microinjection. Results showed that the VLS site was more sensitive to DA receptor blockade than the DMS site to affect water consumption. However, only local infusion of haloperidol, rather than SCH23390, into the VLS site significantly reduced water intake. These data indicate that drinking performance can be sensitive to the heterogeneous functions of the striatum associated with specific dopamine receptor subtypes.