Issue Archive

[Effect of spontaneous firing of injured dorsal root ganglion neuron on excitability of wide dynamic range neuron in rat spinal dorsal horn.] [Article in Chinese]

SONG Ying, ZHANG Yong-Mei, XU Jie, WU Jing-Ru, QIN Xia, HUA Rong

1Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou 221004, China； Department of Emergency Medicine, the 97th Hospital of PLA, Xuzhou 221000, China

Abstract

The aim of the paper is to study the effect of spontaneous firing of injured dorsal root ganglion (DRG) neuron in chronic compression of DRG (CCD) model on excitability of wide dynamic range (WDR) neuron in rat spinal dorsal horn. In vivo intracellular recording was done in DRG neurons and in vivo extracellular recording was done in spinal WDR neurons. After CCD, incidence of spontaneous discharge and firing frequency enhanced to 59.46% and (4.30 ± 0.69) Hz respectively from 22.81% and (0.60 ± 0.08) Hz in normal control group (P < 0.05). Local administration of 50 nmol/L tetrodotoxin (TTX) on DRG neuron in CCD rats decreased the spontaneous activities of WDR neurons from (191.97 ± 45.20)/min to (92.50 ± 30.32)/min (P < 0.05). On the other side, local administration of 100 mmol/L KCl on DRG neuron evoked spontaneous firing in a reversible way (n = 5) in silent WDR neurons of normal rats. There was 36.36% (12/33) WDR neuron showing after-discharge in response to innocuous mechanical stimuli on cutaneous receptive field in CCD rats, while after-discharge was not seen in control rats. Local administration of TTX on DRG with a concentration of 50 nmol/L attenuated innocuous electric stimuli-evoked after-discharge of WDR neurons in CCD rats in a reversible manner, and the frequency was decreased from (263 ± 56.5) Hz to (117 ± 30) Hz (P < 0.05). The study suggests that the excitability of WDR neurons is influenced by spontaneous firings of DRG neurons after CCD.

Key words: chronic compression of DRG; dorsal root ganglion neuron; wide dynamic range neuron; spontaneous firing; after-discharge

Received: 2013-02-20　　Accepted: 2013-05-09

Corresponding author: 宋英　　E-mail: jysongying979@163.com

Citing This Article：

SONG Ying, ZHANG Yong-Mei, XU Jie, WU Jing-Ru, QIN Xia, HUA Rong. [Effect of spontaneous firing of injured dorsal root ganglion neuron on excitability of wide dynamic range neuron in rat spinal dorsal horn.] [Article in Chinese] . Acta Physiol Sin 2013; 65 (5): 533-539 (in Chinese with English abstract).