We investigated whether uninjured cutaneous @entity7183 nociceptors in primates develop abnormal responses after partial denervation of the skin. Partial denervation was induced by tightly ligating spinal nerve L6 that innervates the dorsum of the foot. Using an in vitro skin-nerve preparation, we recorded from uninjured single afferent nerve fibers in the superficial peroneal nerve. Recordings were made from 32 @entity7183 nociceptors 2-3 wk after ligation and from 29 @entity7183 nociceptors in control animals. @entity2647 , a selective alpha1-adrenergic agonist, and @entity16495 (UK), a selective alpha2-adrenergic agonist, were applied to the receptive field for 5 min in increasing concentrations from 0.1 to 100 microM. Nociceptors from in vitro control experiments were not significantly different from nociceptors recorded by us previously in in vivo experiments. In comparison to in vitro control animals, the afferents found in lesioned animals had 1) a significantly higher incidence of spontaneous activity, 2) a significantly higher incidence of response to @entity2647 , and 3) a higher incidence of response to UK. In lesioned animals, the peak response to @entity2647 was significantly greater than to UK, and the mechanical threshold of @entity2647 -sensitive afferents was significantly lower than for @entity2647 -insensitive afferents. Staining with protein gene product 9.5 revealed an approximately 55% reduction in the number of unmyelinated terminals in the epidermis of the lesioned limb compared with the contralateral limb. Thus uninjured cutaneous @entity7183 nociceptors that innervate skin partially denervated by ligation of a spinal nerve acquire two abnormal properties: spontaneous activity and alpha-adrenergic sensitivity. These @entity853 may contribute to @entity9 .

Uninjured XXXX nociceptors develop spontaneous activity and alpha-adrenergic sensitivity following L6 spinal nerve ligation in monkey.

@entity853 :: ('MESH:D009139', 'Disease') :: ['abnormalities in nociceptor function'] @entity7183 :: ('10185', 'Species') :: ['C-fiber'] @entity16495 :: ('MESH:C015620', 'Chemical') :: ['UK14304'] @entity2647 :: ('MESH:D010656', 'Chemical') :: ['phenylephrine', 'Phenylephrine'] @entity9 :: ('MESH:D009437', 'Disease') :: ['neuropathic pain']
@entity7183 :: (10185,Species) :: ['C-fiber']
