Effect on the expression of and after neonatal lesion in the lymphocytes, nucleus accumbens, hippocampus and prefrontal cortex: comparative analysis between juvenile and adult Wistar rats.

Background: Neonatal lesion in the ventral hippocampus (NLVH) is a validated animal model to study schizophrenia from a neurodevelopmental perspective. This animal model is also used to investigate how neonatal lesions may alter the genetic expression of dopaminergic receptors. The present study compares mRNA expression levels of dopamine receptors ( and ) in lymphocytes and brain of NLVH animals at two different age stages: young and adult.

Methods: The NLVH procedure was performed on 20 male Wistar rats at postnatal days 5-7. The mRNA expression levels of and genes in lymphocytes, nucleus accumbens, hippocampus and prefrontal cortex were measured and analyzed at postnatal days 45 and 90. The results were compared and contrasted with respective sham groups.

Results: In lymphocytes, only in NLVH-adult group we observed mRNA expression, while mRNA expression was not observed in the NLVH-juvenile rats; on the other hand, the mRNA expression did not show significant statistical differences. In hippocampus no differences were observed between mRNA or mRNA expression when comparing juvenile/adult shams with NLVH groups. In the prefrontal area, a decrease in mRNA expression levels were observed in the NLVH-adult group (F(1,3) = 52.83,  = 0,005) in comparison to the sham-adult group. Finally, in the nucleus accumbens, a strong decrease of mRNA expression was observed in the NLVH-adult group in comparison to the sham-adult group (F(1,3) = 123,2,  < 0.001).

Conclusions: Our results show that differences in and mRNA levels in NLVH-adults are patent when compared to the sham-adult group or with the NLVH-juvenile group. These findings suggest that the expression levels may be regulated during adulthood, leading to behavioral and neurochemical changes related to schizophrenia. Therefore, more studies are necessary to determine the role of dopamine receptors as possible molecular markers for neurodevelopmental changes associated with schizophrenia.