Zhen Ci Yan Jiu. 1995 ; 20(1): 15-9.

[Influence of SmI lesion on acupuncture-induced analgesia in thalamic Pf neurons and effects of iontophoretic ACh on their nociceptive responses]

Chen Z, Shi H, Wu G, Zheng X, Xu W.

Institute of Acupuncture and Moxibustion, China Academy of Traditional Chinese Medicine, Beijing.

This study aimed to investigate the role of ACh in SmI emanating descending modulation of thalamic Pf neurons in acupuncture analgesia. Multi-micropipettes were used for both extracellularly recording responses of thalamic Pf neurons to noxious stimulation of the plantar area and drug application in rats. It was found that (1) lesion of SmI obviously attenuated the inhibitory effect of EA applied at "Zusanli" and "Huantiao" points on nociceptive responses in Pfneurons; (2) after lesion of SmI iontophoretic application of ACh markedly suppressed the nociceptive responses of Pf neurons, which was significantly different from the effect of iontophoretic NaCl (as the control) showing no influence on them; (3) the inhibition induced by iontophoretic ACh applied in the rats with lesion of SmI was similar to that produced by EA applied in those with SmI intact. It is indicated that EA can activate SmI to release ACh to exert descending modulation, in which ACh is involved in SmI originating descending regulation of Pf neruons in acupuncture analgesia.