RESUMEN
OBJECTIVE: The purpose of our study was to measure and compare the c-fos mRNA expression patterns in the nucleus accumbens (NAS) and prefrontal cortex (PFC) of rats after the administration of haloperidol (2 mg/kg) or (-)-3-PPP (2 mg/kg) plus haloperidol (2 mg/kg). METHODS: Reverse transcriptase-polymerase chain reactions (RT-PCR) were performed on total RNA from samples of the NAS and PFC of rats to detect the expression of c-fos mRNA. As internal control, beta-actin mRNA was co-amplified. The products were separated by electrophoresis, and the density of bands was quantified using an image-analysis software. RESULTS: Both the administration of haloperidol (2 mg/kg) and (-)-3-PPP (2 mg/kg) plus haloperidol (2 mg/kg) increased the c-fos mRNA expression significantly (p<0.05) in the NAS, but had no effects in the PFC. In addition, the coadministration of (-)-3-PPP (2 mg/kg) and haloperidol (2 mg/kg) demonstrated more (0.05) remarkable c-fos mRNA expressions than those obtained with the administration of haloperidol (2 mg/kg) alone. CONCLUSION: These results suggest that the coadministration of (-)-3-PPP and haloperidol may have more potent antipsychotic effect compared to the administration of haloperidol alone.