Noradrenergic Modulation on Dopaminergic Neurons

It is now well accepted that there is a close relationship between noradrenergic and dopaminergic neurons in the brain, especially referring to the modulation of the locus coeruleus–norepinephrine (LC-NE) system on dopamine transmission. The disturbance of this modulation may contribute to neurodegeneration of dopaminergic neurons in Parkinson’s disease. In this article, we briefly review evidence related to such modulation. Firstly, we illustrated the noradrenergic innervation and functional implication for the LC-NE system and nigra–striatum dopaminergic system. Furthermore, we depicted neuroprotective effects of the LC-NE on dopaminergic neurons in vivo and in vitro. Moreover, we present data implicating the potential mechanisms underlying the modulation of the LC-NE system on dopaminergic neurons, in particular the effects of NE as a neurotrophic factor and through its ability to stimulate the expression of other neurotrophic factors, such as the brain-derived neurotrophic factor. Finally, we discussed other mechanisms intrinsic to NE’s effects. A better understanding of the noradrenergic modulation on dopaminergic neurons may be rewarding by significant advances in etiologic study and promising treatment of Parkinson’s disease.