右美托咪啶通过抑制超极化激活内向电流减轻机械性触诱发痛
张芳¹, 古瑞², 冯亚星², 张耀雷², 李薇², 李婷², 张明^2,3,*
1陕西省西安市公安消防支队卫生队，西安 710003；²成都军区总医院中心实验室，成都 610083；³空军军医大学南京医院麻醉与围术期医学科，西安 710032
摘要
本文旨在研究右美托咪啶(dexmedetomidine, DEX)对慢性压迫背根神经节(chronic compression of dorsal root ganglion, CCD)引起的机械性触诱发痛的作用及机制。制备Sprague Dawley (SD)大鼠CCD模型，用痛行为学方法检测机械性触诱发痛，用全细胞膜片钳技术检测背根神经节(dorsal root ganglion, DRG) C类和Aδ类神经元兴奋性和超极化激活内向电流(hyperpolarization-activated inward currents, Ih)的变化。结果显示：鞘内注射DEX显著减轻CCD大鼠机械性触诱发痛(P < 0.05)；在CCD大鼠DRG C类和Aδ类神经元上，DEX显著提高细胞基强度和后超极化电位，降低Ih电流密度。上述结果提示，DEX可能通过抑制C类和Aδ类DRG神经元Ih电流，降低神经元兴奋性，从而减轻神经病理性疼痛。
关键词： 右美托咪啶; 背根神经节; 机械性触诱发痛; 超极化激活内向电流; 神经病理性疼痛
分类号：Q424

Dexmedetomidine suppresses mechanical allodynia by inhibiting hyperpolarization- activated inward current
ZHANG Fang¹, GU Rui², FENG Ya-Xing², ZHANG Yao-Lei², LI Wei², LI Ting², ZHANG Ming^2,3,*
1The Police Fire Brigade Health Team, Xi’an 710003, China；²Central Laboratory, General Hospital of Chengdu Military Command, Chengdu 610083, China；³Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Airforce Medical University of People’s Liberation Army of China, Xi’an 710032, China
Abstract
The purpose of the present study was to investigate the effects of dexmedetomidine (DEX) on neuropathic pain in the chronic compression of dorsal root ganglion (CCD) rat model and the underlying mechanism. Pain behavioral tests were applied to observe the effects of DEX on mechanical allodynia in Sprague Dawley (SD) rats. Whole cell patch clamp was used to observe the influence of DEX on excitability and hyperpolarization-activated inward current (Ih) of C- and Aδ-type dorsal root ganglion (DRG) neurons. The results showed that mechanical allodynia of CCD rats was significantly inhibited by DEX (P < 0.05). In C- and Aδ-type DRG neurons from the CCD rats, DEX significantly increased rheobase and after hyperpolarizing potential, as well as decreased Ih current density. These results suggest that DEX could attenuate the neuropathic pain in the CCD rats, and the mechanism might be related to the depressed Ih current density and excitability of C- and Aδ-type DRG neurons.
Key words: dexmedetomidine; dorsal root ganglion; mechanical allodynia; hyperpolarization-activated inward currents; neuropathic pain

收稿日期：2017-09-25　　录用日期：2018-01-26
通讯作者：张明　　E-mail: artzhangming@163.com
DOI: 10.13294/j.aps.2018.0034
引用本文：
张芳, 古瑞, 冯亚星, 张耀雷, 李薇, 李婷, 张明. 右美托咪啶通过抑制超极化激活内向电流减轻机械性触诱发痛[J]. 生理学报 2018; 70 (3): 253-261.
ZHANG Fang, GU Rui, FENG Ya-Xing, ZHANG Yao-Lei, LI Wei, LI Ting, ZHANG Ming. Dexmedetomidine suppresses mechanical allodynia by inhibiting hyperpolarization- activated inward current. Acta Physiol Sin 2018; 70 (3): 253-261 (in Chinese with English abstract).



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