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[Difference in properties of spontaneous electric activities of visceral nociceptive neurons in bilateral anterior cingulate gyrus of cats.] [Ariticle in Chinese]

WU Min-Fan, YAO Yang, LI Yu-Fang, YANG Yu, TENG Guo-Xi

Department of Physiology, Shenyang Medical College, Shenyang 110034, China； Department of Pharmacology, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China； Laboratory of Neurophysiology, Brain Research Institute, China Medical University, Shenyang 110001, China

Abstract

The aim of the present study is to explore the role of anterior cingulate gyrus (ACG) in bilateral cerebral cortex in visceralnociceptive sensation. Electrical stimulation of greater splanchnic nerve (GSN) was used as visceral nociceptive stimulus, and intracellularrecording techniques in vivo was used to record and analyze the responses to stimuli and spontaneous electric activities of theneurons in the bilateral ACG. According to the responses to electrical stimulation of GSN, the neurons in the bilateral ACG were dividedinto GSN-stimulus-relative neurons (GSRNs) and GSN-stimulus-irrelative ones. According to the characteristics of the evoked responsesto electrical stimulation of the GSN, GSRNs could be further classified into visceral nociceptive neurons (VNNs) and nonvisceralnociceptive neurons (NVNNs). VNNs included specific visceral nociceptive neurons (SVNNs) and non-specific visceralnociceptive neurons (NSVNNs). The results showed that the percentage of GSRNs in the contralateral ACG (38.18%) was signifi- cantly higher than that in the ipsilateral ACG (29.49%, P<0.01), suggesting although GSN afferent fibers project to bilateral ACG, theymainly project to the contralateral ACG. Compared with ipsilateral ACG, contralateral ACG possessed lower proportion of SVNNsand higher proportion of NSVNNs (P<0.01). The absolute values of resting potentials (RP) of GSRNs, VNNs, NVNNs and SVNNs inipsilateral ACG were less than those of corresponding neurons in contralateral ACG. However, there were no significant differences inthe absolute values of RP of NSVNNs between ipsilateral and contralateral ACG. There were no significant differences in modes,frequencies and amplitudes of spontaneous electric activities of VNNs and NVNNs between ipsilateral and contralateral ACG.Additionally, the percentage of neurons having spontaneous electric activities from VNNs was significantly higher than that fromNVNNs, which indicated that the excitability of VNNs was higher than that of the NVNNs in bilateral ACG. These results suggest thatthe patterns and degrees of the responses to nociceptive GSN-stimulation of the ipsilateral and contralateral ACG are different, thusproviding new experimental data for the asymmetry of functions of the bilateral brain.

Key words: anterior cingulate gyrus; visceral pain; nociceptive neuron; intracellular potential; spontaneous biological electric activity

Received: 2010-08-12　　Accepted: 2010-09-08

Corresponding author: 吴敏范　　E-mail: minfanwu0594@sina.com.cn

Citing This Article：

WU Min-Fan, YAO Yang, LI Yu-Fang, YANG Yu, TENG Guo-Xi. [Difference in properties of spontaneous electric activities of visceral nociceptive neurons in bilateral anterior cingulate gyrus of cats.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (5): 450-454 (in Chinese with English abstract).