Alterations in regional brain neurotensin concentrations produced by atypical antipsychotic drugs.

Classical antipsychotic drugs, such as haloperidol, have been shown to increase the concentrations of neurotensin (NT) selectively in the nucleus accumbens and caudate nucleus of the rat. Several novel, putative antipsychotic drugs have also been found to produce increases in NT content in one or both of these brain regions. The present study sought to compare the effects of chronic treatment with three clinically efficacious atypical antipsychotic drugs, sulpiride, rimcazole and remoxipride, on regional brain NT concentrations to those of haloperidol. The concentrations of NT in five discrete brain regions were determined by a sensitive and specific radioimmunoassay. As previously reported, haloperidol increased NT concentrations in both the nucleus accumbens and caudate nucleus. Sulpiride and rimcazole produced significant increases in the concentration of NT in the caudate. NT concentrations were unaltered in any brain region by remoxipride at either of the doses tested. These data provide additional evidence for specific increases in regional brain NT concentrations produced by antipsychotic drugs.