RISPERIDONE DOES NOT ELEVATE NEUROTENSIN MESSENGER-RNA IN RAT NUCLEUS-ACCUMBENS AND CAUDATE-PUTAMEN

THE ability of the novel antipsychotic drug risperidone to alter striatal neurotensin mRNA levels was investigated and compared with the typical antipsychotic drug haloperidol. Quantitative in situ hybridization studies revealed that risperidone treatment does not affect neurotensin mRNA levels in nucleus accumbens or caudate-putamen. This absence of effect contrasts with the dramatic increases in neurotensin mRNA seen after haloperidol treatment in these brain regions. Our results, while conforming the atypical nature of risperidone, do not support the notion that neurotensin elevation in the nucleus accumbens is necessary for the development of an antipsychotic effect.