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[Changes in voltage-gated potassium currents in the trigeminal neurons after a chronic constriction of infraorbital nerve.] [Ariticle in Chinese]

LI Na, LI Chao, FAN Juan, JIANG Xiao-Zhong, LI Jin-Bao, DENG Xiao-Ming, MA Bei

Department of Anaesthesia, Changhai Hospital, Second Military Medical University, Shanghai 200433, China； Department of Stomatology, Changzheng Hospital, Second Military Medical University, Shanghai 200002, China； Department of Physiology, Second Military Medical University, Shanghai 200433, China

Abstract

The purpose of this study was to establish a model of trigeminal neuralgia (TN) through an approach from lower edge of cheekbone and to observe the functional changes in the voltage-gated potassium currents in the cultured trigeminal ganglion (TG) neurons. Thirty Sprague-Dawley male rats were divided into two groups, the sham-operated (sham) group and the operated group. The TN model was carried out by using a chronic constriction injury of the infraorbital nerve (ION-CCI) from lower edge of cheekbone. Peripheral pain threshold test and whole-cell patch clamp recording were used to determine the difference between sham and ION-CCI rats. The withdrawal threshold of whisker pad in operated side of ION-CCI rat was decreased significantly from 6 d after operation and then maintained until 21 d, with the lowest on the 15th day. The threshold of whisker pad in non-operated side of operated rats was also decreased significantly compared with that in the sham group. Delayed rectifier potassium current (IK) in cultured ION-CCI TG neurons was decreased significantly compared with that in the sham group. Transient outward potassium currents (IA) in both operated and nonoperated sides of TG neurons from ION-CCI rats were also reduced significantly compared with that in the sham group. The present study provided a new method of ION-CCI. In this model, the decrease of IA and IK might contribute, at least in part, to the decrease in mechanical pain threshold of whisker pad and the subsequent hyperalgia.

Key words: trigeminal neuralgia; potassium channels, voltage-gated; trigeminal ganglion; patch-clamp techniques;

Received: 2008-10-31　　Accepted: 2008-12-11

Corresponding author: 邓小明　　E-mail: xmdeng@anesthesia.org.cn

Citing This Article：

LI Na, LI Chao, FAN Juan, JIANG Xiao-Zhong, LI Jin-Bao, DENG Xiao-Ming, MA Bei. [Changes in voltage-gated potassium currents in the trigeminal neurons after a chronic constriction of infraorbital nerve.] [Ariticle in Chinese] . Acta Physiol Sin 2009; 61 (1): 72-78 (in Chinese with English abstract).