脊髓背角神经元对胃扩张及电针“足三里”穴的反应

Responses of Spinal Dorsal-horn Neurons to Gastric Distention and Electroacupuncture of "Zusanli" Point

目的 :本实验以猫胸段具有自发活动的背角神经元的放电频率为指标 ,观察了胃扩张和电刺激左侧内脏大神经引起的神经元电活动变化以及电针左侧“足三里”穴和“三阴交”穴的影响。方法 :采用玻璃微电极脑外记录神经元的电活动。工作参数如下 ,电针穴位 :3V ,3 0Hz,方波 ,连续 1 0sec;内脏大神经 :1mA ,双脉冲 ,间隔 4ms,波宽 2 0 0 μs,连续 1 0sec;胃充盈 :8mmHg( 1 0 64kPa)。结果 :①在所观察的 2 4个神经元中 ,1 3个对胃扩张刺激呈增频反应 ,1 1个为减频反应 ;电针“足三里”穴能够翻转或拮抗这种改变 ,即抑制增频神经元 ( 62 .50± 6.52 ,与 2 3 .3 0± 6.86相比 ,P <0 .0 5,脉冲个数 ,M±SE ,下同 ) ,兴奋减频神经元 ( 1 9.1 0± 4.72 ,与 71 .60± 1 7.50相比 ,P <0 .0 5)。电针“三阴交”穴具有类似功能 ,但作用较弱 ,无统计学意义 ;②在 2 1个 ( 2 1 / 2 4)神经元中 ,电刺激左侧内脏大神经可兴奋 1 3个神经元 ,抑制 7个神经元 ,其中 3个为完全抑制 ;③刺激内脏大神经同时电针“足三里”穴可见到后者对前者显著的抑制效应。结论 :①躯体与内脏的信息在脊髓水平汇聚并整合 ,进而通过改变内脏传出神经的活动达到调整治疗的目的 ;

Objective: To observe the influence of stomach dilation or electrical stimulation of the left grea ter splanchnic nerve (GSN) on the discharge frequency of dorsal horn neurons of the thoracic (8th) spinal cord and to compare the effects of electroacupuncture of 'Zusanli'(ST 36) and 'Sanyinjiao'(SP 6) on the electrical activity of dorsal horn neurons in the cat. Methods: Healthy cats anesthetized with mixture solution of urethane (500 mg/kg) chloralose (50 mg/kg) (i.p.) were used in the present study. Glass micropipettes with tip diameter being about 1～ 2 μm were employed for recording the electrical activity of dorsal horn neurons of the spinal cord. After opening the abdominal cavity and making an incision at the junction between the pylorus and duodenum, a plastic balloon was inserted into the stomach, with the other end being connected to air pump and pressure transducer. The left GSN was isolated and placed on a silver bipolar stimulating electrode. Left 'Zusanli'(ST 36) and 'Sanyinjiao'(SP 6) were stimulated with an Electroacupuncture Apparatus (ZYZ ZOZG1) by setting the stimulating parameters being 3 V, 30 Hz and duration of 10 sec.Results: ① Of all the 24 neurons recorded, after gastric dilation, 13 were excited and 11 inhibited. Electroacupuncture of 'Zusanli' (ST 36) may turn over these changes, that is, to reduce the firing rate of the excited neurons (62.50 ±6.52 vs 23.30±6.86, P<0.05, M±SE, the same below) or to increase the firing rate of the inhibited neurons (19.10±4.72 vs 71.60±17.50, P<0.05). Electroacupuncture of'Sanyinjiao'produced the similar but weaker effect and there existed no statistical significance between pre and post EA (P>0.05). ② Of the 21 (21/24) neurons, following electrical stimulation of GSN, 13 neurons were excited and 7 inhibited. 3 (3/7) neurons were totally inhibited. Electroacupuncture at 'Zusanli' (ST 36) produced remarkable inhibition on the discharge increase of dorsal horn neurons induced by the electrical stimulation of GSN. Conclusion: ①The somatic and visceral message may converge to the spinal cord; ② Acupuncture has a bi directional regulatory action on the nocuous input of the internal organs. The research provided new evidence for the theory of 'relationship between acupoints and visceral organs' in TCM.