Role of SmallFiber Afferents in Pain Mechanisms W

Authors: Phillip J Albrecht Frank L Rice

Publish Date: 2010/04/23

Volume: 14, Issue: 3, Pages: 179-188

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Abstract

Numerous mechanisms are implicated in the perception of pain Although many anatomical molecular and functional components have been identified a comprehensive and integrated theory of pain perception has yet to be firmly established that fits the diverse clinical experience Acute pain involves the activation of several varieties of small primary sensory neurons collectively termed nociceptors which have smallcaliber unmyelinated or myelinated axons C and Aδ fibers respectively that innervate all body tissues They are stimulated by noxious stimuli that activate ion channels on the endings either directly or through the release of cytokines from damaged or stressed tissues A variety of drugs successfully treats acute pain by targeting these ion channels or cytokine interactions Paradoxically several chronic neuropathic pain conditions are associated with a loss of smallcaliber axons and have an unpredictable and poor response to current drugs especially at doses that do not cause severe side effects In an attempt to further an integrated theory of pain perception this review focuses upon the presumed role of smallcaliber innervation particularly to the epidermis and cutaneous vasculature and the clinical manifestations diagnosis and treatment of pathologies of this innervationDr Phillip J Albrecht and Dr Frank L Rice have received fair market compensation for performing basic research contracts and/or consultation on behalf of Johnson Johnson AstraZeneca Endo Pharmaceuticals Vertex Pharmaceuticals Novartis Forest Laboratories and Eli Lilly Neither author has any conflicts of interest to declare

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