Afferent fibers mediate the increase of met-enkephalin elicited in rat spinal cord by localized pain

Publisher Website
Google Scholar
Abstract
Met-enkephalin levels were measured in various spinal cord regions of rats chronically suffering from the inflammation of a single paw following a treatment with Freund''s adjuvant. Chronic localized pain induces a selective increase of met-enkephalin immunoreactive material (ME-IR) in the dorsal horn of the spinal cord segment which receives a direct projection from the inflamed paw. The plexus brachialis or the sciatic nerve were sectioned peripherally before inducing inflammation for functional data interpetation. Denervation prevented the increase of ME-IR concentration induced by the injection of Freund''s adjuvant. Chronic localized pain in a limb induces a change in ME-IR content which is selective for the spinal cord segment receiving a direct projection from the inflamed paw. This increase depends on an intact innervation.