کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9720976 | 1473268 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Peripheral axonal injury results in reduced μ opioid receptor pre- and post-synaptic action in the spinal cord
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
علوم اعصاب سلولی و مولکولی
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چکیده انگلیسی
In both the spared nerve injury (SNI) and spinal nerve ligation (SNL) rat peripheral neuropathic pain models the presynaptic inhibitory effect of the μ opioid receptor (MOR) agonist (DAMGO) on primary afferent-evoked excitatory postsynaptic currents (EPSCs) and miniature EPSCs in superficial dorsal horn neurons is substantially reduced, but only in those spinal cord segments innervated by injured primary afferents. The two nerve injury models also reduce the postsynaptic potassium channel opening action of DAMGO on lamina II spinal cord neurons, but again only in segments receiving injured afferent input. The inhibitory action of DAMGO on ERK (extracellular signal-regulated kinase) activation in dorsal horn neurons is also reduced in affected segments following nerve injury. MOR expression decreases substantially in injured dorsal root ganglion neurons (DRG), while intact neighboring DRGs are unaffected. Decreased activation of MOR on injured primary afferent central terminals and the second order neurons they innervate may minimize any reduction by opioids of the spontaneous pain mediated by ectopic input from axotomized small diameter afferents. Retention of MOR expression and activity in nearby non-injured afferents will enable, however, an opioid-mediated reduction of stimulus-evoked and spontaneous pain carried by intact nociceptor afferents and we find that intrathecal DAMGO (1000 ng) reduces mechanical hypersensitivity in rats with SNL. Axotomy-induced changes in MOR may contribute to opioid- insensitive components of neuropathic pain while the absence of these changes in intact afferents may contribute to the opioid sensitive components.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Pain - Volume 117, Issues 1â2, September 2005, Pages 77-87
Journal: Pain - Volume 117, Issues 1â2, September 2005, Pages 77-87
نویسندگان
Tatsuro Kohno, Ru-Rong Ji, Nobuko Ito, Andrew J. Allchorne, Katia Befort, Laurie A. Karchewski, Clifford J. Woolf,