کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2494847 1115582 2008 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Selective ablation of dorsal horn NK1 expressing cells reveals a modulation of spinal alpha2-adrenergic inhibition of dorsal horn neurones
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب رفتاری
پیش نمایش صفحه اول مقاله
Selective ablation of dorsal horn NK1 expressing cells reveals a modulation of spinal alpha2-adrenergic inhibition of dorsal horn neurones
چکیده انگلیسی

Activity in descending systems from the brainstem modulates nociceptive transmission through the dorsal horn. Intrathecal injection of the neurotoxin saporin conjugated to SP (SP–SAP) into the lumbar spinal cord results in the selective ablation of NK1 receptor expressing (NK1+ve) neurones in the superficial dorsal horn (lamina I/III). Loss of these NK1+ve neurones attenuates excitability of deep dorsal horn neurones due to a disruption of both intrinsic spinal circuits and a spino-bulbo-spinal loop, which activates a descending excitatory drive, mediated through spinal 5HT3 receptors.Descending inhibitory pathways also modulate spinal activity and hence control the level of nociceptive transmission relayed to higher centres. To ascertain the spinal origins of the major descending noradrenergic inhibitory pathway we studied the effects of a selective alpha2-adrenoceptor antagonist, atipamezole, on neuronal activity in animals pre-treated with SP–SAP. Intrathecal application of atipamezole dose dependently facilitated the mechanically evoked neuronal responses of deep dorsal horn neurones to low intensity von Frey hairs (5–15 g) and noxious thermal (45–50 °C) evoked responses in SAP control animals indicating a physiological alpha2-adrenoceptor control. This facilitatory effect of atipamezole was lost in the SP–SAP treated group. These data suggest that activity within noradrenergic pathways have a dependence on dorsal horn NK1+ve cells. Further, noradrenergic descending inhibition may in part be driven by lamina I/III (NK1+ve) cells, and mediated via spinal alpha2-adrenoceptor activation. Since the same neuronal population drives descending facilitation and inhibition, the reduced excitability of lamina V/VI WDR neurones seen after loss of these NK1+ve neurones indicates a dominant role of descending facilitation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuropharmacology - Volume 54, Issue 8, June 2008, Pages 1208–1214
نویسندگان
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