在针刺镇痛中海马结构单位放电的变化

以记录单个神经元电活动的方法对海马结构在针刺镇痛中的作用进行研究。证明CA1,CA2和齿状回有些神经元对外周伤害性刺激,发生两种不同类型的反应。一是增频反应(伤害性兴奋神经元NEN),一种是减频反应(伤害性抑制神经元NIN)。电针穴位对多数NEN有抑制作用,而对NIN有解除抑制的效应,向动物体内注入吗啡也出现与针刺穴位类似的作用。电刺激中缝大核或中脑导水管周围灰质(PAG),对多数NEN和NIN也有影响,结果类似针刺穴位的效应。向动物侧脑室注入或微电泳5-HT,海马单位的NEN和NIN也出现与针刺穴位相同的效应。这些结果提示,针刺穴位对海马单位电活动的影响可能与脑内5-HT能神经元的活动有关。另外,也可能有内源性吗啡样物质的参与。 向侧脑室内注入大剂量的γ-氨基丁酸(GABA),也可抑制NEN的活动。但这与海马内GABA能中间神经元的生理性活动有何关系,尚需进一步证实。

The Alterations of Unit Discharges of Hippocampal Formation in Acupuncture Analgesia

The actions of the hippocampal formation were studied by recording the electrical activities of a single neuron of that area. Two different reactions of some neurons in CAl, CA2 and the dentate gyrus might occur after peripheral noxious stimulations, that is, the increasing of the reaction frequency of the nociceptive excited neurons(NEN) and the decreasing of the reaction frequency of the nociceptive inhibited neurons (NIN). Electrical acupuncture of the "points" would result in inhibiting effect on most of the NENs but disinhibiting effect on NINs, Identical effect to that of acupuncture could be created by injecting morphine to the experimental animals. Electrical stimulation of the nucleus raphe magnus or para-aqueduct gray matter(PAG) could affect the NENs and NINs in the hippocampus, and the results were similar to that of acupuncture. When 5-HT was injected into the lateral ventricle or applied to the hippocampal neurons through micro-iontophoresis, effects similar to that of acupuncture also occurred. These facts imply that the effects of peripheral "point" acupuncture on the electrical activities of the neurons of the hippocampal formation might be related to the activities of the endogenous 5-HTergic neurons, or to the endogenous morphine-like substance. The NENs would be inhibited after large amounts of GABA were injected into the lateral ventricle. The inter-relationship between this phenomenon and the activities of GABAergic interneu.rons in the hippocampus awaits further investigation.