He X L, Liu X, Zhu B, Xu W D, Zhang S X
Institute of Acupuncture and Moxibustion, China Academy of Traditional Chinese Medicine, Beijing.
Sheng Li Xue Bao. 1995 Dec;47(6):605-9.
Experiments were performed on male rats. The responses of dorsal horn convergent neurons in spinal cord (T12-L1) to noxious stimulation of hind paw were recorded extracellularly with glass microelectrode. When low intensity (2 V) electroacupuncture (EA) was used, the nociceptive responses of convergent neurons were inhibited by EA at "Zusanli" near noxious stimulation area, but not at "Xiaguan" far from the area. When intensity (18 V) high than the threshold of C fibers EA was applied at the far acupoint "Xiaguan", obvious analgesic effects on convergent neurons were also produced, showing an extensive analgesic effect of strong EA at acupoint. This extensive analgesic effect was abdicated by lesion of nucleus raphe magnus (NRM), but still persisted to some extent by EA at the same segment acupoint "Zusanli" with 18 V or 2 V intensity. The results suggest that, the extensive analgesia of strong EA at far segment acupoint may be mainly mediated by noxious stimulation through NRM, a negative feedback mechanism modulating pain of supraspinal cord. The analgesia due to 2 V EA at the same segment acupoint may be mainly produced by gate control in spinal cord, but also to some extend by supraspinal cord mechanism.
实验在雄性大鼠身上进行。用玻璃微电极细胞外记录脊髓（T12-L1）背角汇聚神经元对后爪伤害性刺激的反应。当使用低强度（2V）电针时，在伤害性刺激区域附近的“足三里”进行电针可抑制汇聚神经元的伤害性反应，而在远离该区域的“下关”则无此作用。当在远部穴位“下关”施加高于C纤维阈值强度（18V）的电针时，对汇聚神经元也产生明显的镇痛作用，表明强电针在穴位具有广泛的镇痛效应。这种广泛的镇痛效应在中缝大核（NRM）损毁后消失，但在同一节段穴位“足三里”以18V或2V强度进行电针时仍有一定程度的持续。结果提示，远节段穴位强电针的广泛镇痛可能主要由伤害性刺激通过NRM介导，这是一种脊髓上痛觉调制的负反馈机制。同一节段穴位2V电针产生的镇痛可能主要由脊髓闸门控制产生，但也有一定程度是由脊髓上机制介导。
