Analgesia induced by perineural clonidine is enhanced in persistent neuritis.

Alpha 2-adrenoceptors are concentrated near sites of peripheral nerve injury or inflammation, primarily on immune cells, and their activation reduces inflammation and hypersensitivity to tactile stimuli. These results were obtained during acute inflammation, but the efficacy of alpha2-adrenoceptor stimulation in persistent inflammation has not been tested. Here, we show that perineural injection of the alpha2-adrenoceptor agonist, clonidine, reduces hypersensitivity in persistent sciatic neuritis with an onset more rapid than acute neuritis.

Spinal glial activation contributes to postoperative mechanical hypersensitivity in the rat.

Unlabelled: The activation of spinal cord microglia and astrocytes after peripheral nerve injury or inflammation contributes to behavioral hypersensitivity. The contribution of spinal cord glia to mechanical hypersensitivity after hind paw incision has not been investigated previously. Male Sprague-Dawley rats underwent a unilateral plantar hind paw incision, and the development of mechanical hypersensitivity was assessed by using von Frey filaments.