Expression of dopaminergic transcription factors in prenatally stressed adult rats

MR KATUNAR, A. BRUSCO Y MC ANTONELLI

Puccon, Chile

Simposio; III Neurotoxiccity Society Meeting; 2007

Neurotoxicity Society (NTS)

Stress applied to the gestant dam was shown to produce long-term effects on the adult offspring. We have previously shown that prenatal stress (PS) increases D2-type dopamine (DA) receptor levels with a concomitant reduction in dopamine release after amphetamine stimulation in prenatally stressed rats of 4 weeks old and a significant reduction of dendritic arborization, synaptic contacts and a pronounced astrocytic reaction. The precise anatomical localization and functional differentiation of dopaminergic neurons is achieved through  the effect and gradient disposition of several induction signals. It has recently been identified two transcription factors Nurr1 and Pitx3 wich are expressed at critical moments of DA neurons differentiation.Their genetic expression is activated immediately after these neurons determination and maintained through adult life. Employing an inmunocitochemistry approach, we studied the expression levels of these factors in mesencephalon slices of prenatally stressed adult rats.  Nurr1 expression was localized in periaqueductal ependymals cells, whereas Pitx3 expression was restricted to Sustantia Nigra, compact and reticular (SNc and SNr) and to ventral tegmental area (VTA). PS rats showed an increse in Pitx3 positive nucleus. Since Pitx3 modulates the expression of the key enzyme in dopamine synthesis, tirosine hidroxylase, the increase of Pitx3 in the adult prenatally stressed rat might be a compensatory mechanism to counteract the decrease of dopamine levels observed at early stages.