DIFFERENTIAL EXPRESSION OF NURR1 IN THE VENTRAL TEGMENTAL AREA OF LOW AND HIGH NICOTINE-RESPONDER RATS

PASTOR, V. ; ANDRÉS, M.E. ; BERNABEU, R.

Huerta Grande, Cordoba.

Congreso; First join meeting of the Argentine Society fro Neurosciences; 2009

The transcription factor Nurr1, a member of the NGFI-B family of nuclear orphan receptors, is highly expressed in rodent midbrain dopamine neurons and is essential for their phenotypic development and maintenance. There are several lines of evidence indicating that nicotine produces behavioral effects via actions on the mesolimbic dopamine system. However, it is still unknown whether Nurr1 participates in nicotine-induced behavioral changes. Locomotor horizontal activity in rats is a behavioral index of nicotine effect on the brain. We evaluated the locomotor response to an acute nicotine injection, obtaining two groups: high and low responder rats. In these animals, we measured Nurr1 protein expression in the ventral tegmental area (VTA). In addition, we trained the animals in a conditioned place preference (CPP) test, in order to evaluate nicotine rewarding properties in these two behavioral groups. Our results showed that in the VTA of high nicotine responders, Nurr1 expression is increased compared to low responders. These two behavioral groups displayed no significant differences in the CPP test. These preliminary findings indicate that an increased expression of Nurr1 in the VTA accompany nicotine-induced locomotor activity. However, low and high responder rats performed equally when rewarding properties of nicotine were assessed by CPP.