Activity-dependent Nurr1 and NGFI-B gene expression in adult mouse olfactory bulb.

Previous studies showed that Nurr1 is essential to development of the dopamine phenotype in midbrain, but not for dopaminergic neurons intrinsic to the olfactory bulb (OB). The current study investigated the distribution of Nurr1 and NGFI-B as well as a role for both of these related orphan receptors in tyrosine hydroxylase (TH) expression in OB. Both NGFI-B and Nurr1 mRNAs were found in the glomerular and granule cell layers of OB. In contrast, only Nurr1 occurred in midbrain dopamine neurons. Both receptors as well as TH exhibited down-regulation in OB in response to odor deprivation produced by unilateral naris closure. These data suggest that in OB, both Nurr1 and NGFI-B may participate in development and regulation of the dopamine phenotype.