COEXPRESSION OF NEUROTENSIN AND C-FOS MESSENGER-RNAS IN RAT NEOSTRIATAL NEURONS FOLLOWING ACUTE HALOPERIDOL

Our previous studies have shown several fold induction of neurotensin/ neuromedin N (NT/N) primary transcripts and mature cytosolic mRNA in t he dorsolateral region of the rat neostriatum (DLSt) following a singl e dose of the neuroleptic, haloperidol. The apparent enhancement of NT /N gene transcription by haloperidol is preceded by increases in the e xpression of c-fos mRNA in the same region. The present study used dou ble-labeling in situ hybridization technique to study cellular localiz ation of NT/N and c-fos mRNA following acute haloperidol treatment. Si multaneous detection of NT mRNA and c-fos mRNA was achieved using cRNA probes synthesized in vitro with digoxigenin- and S-35-labeled UTP, r espectively. Interestingly, approximately 75% of DLSt neurons expressi ng NT/N mRNA also displayed c-fos mRNA in rats treated with haloperido l (1 mg/kg, i.p.) for 1 h. Colocalization of c-fos mRNA in haloperidol -responsive NT neurons in the DLSt suggests that haloperidol's inducti on of NT/N gene transcription may involve participation of the transcr iption factor Fos and the AP-1 consensus sequence in regulatory region of the NT/N gene.