Sex- and estrous cycle-related differences in the effects of acute antipsychotic drug administration on neurotensin-containing neurons in the rat brain

The effects of a single injection of haloperidol (2.0 mg/kg), a typical ant ipsychotic drug, on neurotensin (NT) concentrations and NT/neuromedin N (NT /NN) mRNA expression in adult female and male rats were examined. There wer e significant estrous cycle stage-related differences in both NT concentrat ions and NT/NN mRNA expression in female control rats. Although acute admin istration of haloperidol increased NT concentrations and NT/NN mRNA express ion in the caudate/putamen and nucleus accumbens of both male and female ra ts, haloperidol did not increase NT/NN mRNA expression during diestrus 2 or NT concentrations during proestrus in the nucleus accumbens of female rats . These results indicate the presence of both sex- and estrous cycle-relate d differences in the regulation of NT-containing neurons and in the effects of antipsychotic drug administration on the NT system of the rat brain.