title: Increased expression of cutaneous α1-adrenoceptors after chronic constriction injury in rats.
abstract: α1-Adrenoceptor expression on nociceptors may play an important role in sympathetic-sensory coupling in certain neuropathic pain syndromes. The aim of this study was to determine whether α1-adrenoceptor expression was upregulated on surviving peptidergic, nonpeptidergic, and myelinated nerve fiber populations in the skin after chronic constriction injury of the sciatic nerve in rats. Seven days after surgery, α1-adrenoceptor expression was upregulated in the epidermis and on dermal nerve fibers in plantar skin ipsilateral to the injury but not around blood vessels. This α1-adrenoceptor upregulation in the plantar skin was observed on all nerve fiber populations examined. However, α1-adrenoceptor expression was unaltered in the dorsal hind paw skin after the injury. The increased expression of α1-adrenoceptors on cutaneous nociceptors in plantar skin after chronic constriction injury suggests that this may be a site of sensory-sympathetic coupling that increases sensitivity to adrenergic agonists after nerve injury. In addition, activation of upregulated α1-adrenoceptors in the epidermis might cause release of factors that stimulate nociceptive signaling.
  
  
  CONCLUSIONS
  Our findings indicate that peripheral nerve injury provokes upregulation of α1-adrenoceptors on surviving nociceptive afferents and epidermal cells in the skin. This might contribute to sympathetically maintained pain in conditions such as complex regional pain syndrome, painful diabetic neuropathy, and postherpetic neuralgia.
authors.affiliation: Centre for Research on Chronic Pain and Inflammatory Diseases, Murdoch University, Perth, Western Australia.
authors.forename: Eleanor S
authors.initials: ES
authors.lastname: Drummond
authors.affiliation: Centre for Research on Chronic Pain and Inflammatory Diseases, Murdoch University, Perth, Western Australia.
authors.forename: Linda F
authors.initials: LF
authors.lastname: Dawson
authors.affiliation: Centre for Research on Chronic Pain and Inflammatory Diseases, Murdoch University, Perth, Western Australia.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Finch
authors.affiliation: Department of Anesthesia, Faculty of Dentistry, and The Alan Edwards Centre for Research on Pain, McGill University, Montréal, Quebec, Canada.
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Bennett
authors.affiliation: Centre for Research on Chronic Pain and Inflammatory Diseases, Murdoch University, Perth, Western Australia. Electronic address: P.Drummond@murdoch.edu.au.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Drummond
mesh_terms: D000818:Animals; D002908:Chronic Disease; D003251:Constriction, Pathologic; D004817:Epidermis / Q000294:innervation / Q000378:metabolism / Q000473:pathology; D006614:Hindlimb / Q000098:blood supply / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D008297:Male; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000378:metabolism* / Q000473:pathology; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D009619:Nociceptors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*; D012584:Sciatic Nerve / Q000293:injuries; D020426:Sciatic Neuropathy / Q000378:metabolism* / Q000473:pathology; D012867:Skin / Q000098:blood supply / Q000294:innervation / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation
chemical_list: D018340:Receptors, Adrenergic, alpha-1
keywords: chronic constriction injury; keratinocytes; neuropathic pain; nociceptors; sensory-sympathetic coupling; α(1)-adrenoceptors