Perineural XXXX activation inhibits spinal cord neuroplasticity and tactile allodynia after @entity128 .

@entity1 @entity268 @entity1338 @entity23510 @entity128 @entity1342 @entity1897 @entity56 @entity158 @entity35 @entity1118
BACKGROUND: @entity128 in animals increases alpha(2)-adrenoceptor expression in dorsal root ganglion cells and results in novel excitatory responses to their activation, perhaps leading to the phenomenon of sympathetically maintained @entity158 . In contrast to this notion, peripheral alpha(2)-adrenoceptor stimulation fails to induce @entity158 in @entity1 with @entity1118 . We hypothesized that alpha(2) adrenoceptors at the site of @entity128 play an inhibitory, not excitatory role. METHODS: Partial sciatic nerve ligation was performed on @entity35 , resulting in a reduction in withdrawal threshold to tactile stimulation. Animals received perineural injection at the injury site of @entity1338 , saline, or @entity1338 plus an alpha(2)-adrenergic antagonist, and withdrawal threshold was monitored. Immunohistochemistry was performed on the sciatic nerve ipsi- and contralateral to injury and on the spinal cord. RESULTS: @entity1338 reduced this @entity56 in a dose-dependent manner, and this was blocked by an alpha(2A)-preferring antagonist. Perineural @entity1338 injection had a slow onset (days) and prolonged duration (weeks). Systemic or intrathecal @entity1338 , or transient neural blockade with @entity1342 , had short lasting or no effect on @entity56 . @entity23510 immunostaining was increased near the site of @entity1897 , both in neurons and in immune cells (macrophages and T lymphocytes). Phosphorylated @entity268 response element binding protein (pCREB) in lumbar spinal cord was increased ipsilateral to @entity128 , and this was reduced 1 week after perineural @entity1338 injection. CONCLUSIONS: These data suggest that peripheral alpha(2) adrenoceptors are concentrated at the site of @entity1897 , and their activation receptors produce long-lasting reductions in abnormal spinal cord gene activation and mechanical @entity56 .
