The nucleus accumbens is a site of action for the inhibitory effect of ritanserin on ethanol intake in rats.

The present study evaluated the effect of central injections of the 5-HT2/1C receptor antagonist, ritanserin, on ethanol intake in rats with developed preference for 3% ethanol. Intracerebroventricular (ICV) injections of ritanserin (10 micrograms/rat/day for 10 days) decreased ethanol preference, while subcutaneous (SC) treatment with the same dose was ineffective. Ritanserin ICV, 1 microgram/rat/day, did not reduce alcohol preference. Bilateral injections of ritanserin into the nucleus accumbens (NAC; 0.5 microgram/site/day for 10 days) produced a prompt and very pronounced suppression of ethanol preference, without affecting total fluid intake. Bilateral injections of ritanserin (0.5 microgram/site/day for 10 days) into the ventral tegmental area (VTA) or into the medial prefrontal cortex (MPC) evoked only slight and variable reduction of ethanol preference. Injections of ritanserin, 5 micrograms/site/day, into the VTA gave a nonselective suppression of the ingestive behavior. The present results provide evidence for a central site of action for the effect of ritanserin on ethanol intake and suggest that the NAC might be a highly sensitive site for its action. Since the NAC is a major target of the mesolimbic dopaminergic system, they also suggest that the effect of ritanserin might be due to interference with this system.