Changes in the alpha 2-adrenergic receptor subtypes gene expression in rat dorsal root ganglion in an experimental model of neuropathic pain.

We examined changes in expression of genes coding for alpha 2-AR subtypes in the dorsal root ganglion (DRG) in a rat model (spinal nerve ligation) or neuropathic pain. The present study demonstrates that the majority of DRG neurons express alpha 2C-AR mRNA and a small proportion of neurons express alpha 2A-AR mRNA, while few neurons express alpha 2B-AR mRNA in non-operated animals. In addition, alpha 2C- and alpha 2A mRNA levels in the DRG showed a significant decrease and increase, respectively in ligated animals. These findings suggest that alpha 2A- and alpha 2C-ARs in the DRG may play an important role in generating sympathetically maintained neuropathic pain.