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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

Received: 2017-09-25　　Accepted: 2018-01-26

Corresponding author: 张明　　E-mail: artzhangming@163.com

DOI: 10.13294/j.aps.2018.0034

Citing This Article：

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).