Expression of c-fos in the nucleus of the solitary tract following electroacupuncture at facial acupoints and gastric distension in rats

Clinical practice has shown that acupuncture at facial acupoints has curative effects on some visceral diseases (especially gastrointestinal diseases). However, the physiological basis has not been clarified yet. In the present study, expression of c-fos in the nucleus of the solitary tract (NTS) of rats following gastric distension and electroacupuncture (EA) at Yangbai (GB14) and Sibai (ST2) as well as Jiache (ST6) acupoints was observed by using immunohistochemistry technique. After EA at the three facial acupoints, c-fos immunoreactive (c-fos-IR) neurons were mainly distributed in the medial (mNTS) and intermediate subnucleus of the NTS, and a few were scatteredly distributed in the dorsalmedial and commissural subnucleus of the NTS. Furthermore, there is difference in the number of c-fos-IR neurons in the mNTS following EA at the three facial acupoints. The number in the EA at ST2 and GB14 group is the highest and the lowest, respectively. Gastric distension induces obviously the expression of c-fos, which is mainly confined in the mNTS. The results suggest that the noxious visceral and somatic afferent information from the stomach and face may converge in the mNTS, which may be involved in the effect of EA at facial acupoints on the gastrointestinal pain.