Upregulation of 伪₁-adrenoceptors on cutaneous nerve fibres after partial sciatic nerve ligation and in complex regional pain syndrome type II

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• 作者：Peter D. Drummond ; Eleanor S. Drummond ; Linda F. Dawson ; Vanessa Mitchell ; Philip M. Finch ; Christopher W. Vaughan ; Jacqueline K. Phillips
• 关键词：伪1-Adrenoceptors ; Upregulation ; Partial sciatic nerve lesion ; Complex regional pain syndrome ; Immunohistochemistry
• 刊名：Pain
• 出版年：March, 2014
• 年：2014
• 卷：155
• 期：3
• 页码：606-616
• 全文大小：2203 K

文摘

After peripheral nerve injury, nociceptive afferents acquire an abnormal excitability to adrenergic agents, possibly due to an enhanced expression of 伪₁-adrenoceptors (伪₁-ARs) on these nerve fibres. To investigate this in the present study, changes in 伪₁-AR expression on nerve fibres in the skin and sciatic nerve trunk were assessed using immunohistochemistry in an animal model of neuropathic pain involving partial ligation of the sciatic nerve. In addition, 伪₁-AR expression on nerve fibres was examined in painful and unaffected skin of patients who developed complex regional pain syndrome (CRPS) after a peripheral nerve injury (CRPS type II). Four days after partial ligation of the sciatic nerve, 伪₁-AR expression was greater on dermal nerve fibres that survived the injury than on dermal nerve fibres after sham surgery. This heightened 伪₁-AR expression was observed on nonpeptidergic nociceptive afferents in the injured sciatic nerve, dermal nerve bundles, and the papillary dermis. Heightened expression of 伪₁-AR in dermal nerve bundles after peripheral nerve injury also colocalized with neurofilament 200, a marker of myelinated nerve fibres. In each patient examined, 伪₁-AR expression was greater on nerve fibres in skin affected by CRPS than in unaffected skin from the same patient or from pain-free controls. Together, these findings provide compelling evidence for an upregulation of 伪₁-ARs on cutaneous nociceptive afferents after peripheral nerve injury. Activation of these receptors by circulating or locally secreted catecholamines might contribute to chronic pain in CRPS type II.