损毁双侧伏核对电针“足三里”激活中缝大核效应的影响

<正> 我们以往的工作证明电针大鼠“足三里”可激活中缝大核(NRM)神经元,并抑制其伤害性反应。这种效应可被纳洛酮所翻转。NRM是下行抑制系统的主要起源部位又可看做脑内镇痛系统的最后驿站。它的活动的受脑内高位镇痛中枢的调控,在整体内发挥镇痛作用。我们以往研究了导水管周围灰质(PAG)和尾核对NRM的调控作用,看到损毁PAG和尾核头部后电针“足三里”的镇痛作用均明显减弱。代核为位于脑中线附近的结构,有吗啡受体及脑啡肽能神经纤维的分布。伏核微量注射吗啡可引起镇痛作

THE INFLUENCE OF LESION OF BILATERAL N. ACCUMBENS UPON THE EFFECTS OF ELECTROACUPUNCTURE ON NRM NEURONS

Our previous work demonstrated that periaqueductal gray matter (PA G) and head of N. caudate participate in the effect of EA on neuron of N. raphe magnus (NRM), and the action involve in endorphin within them. N. accumbens (NAC) was a structure near the middle line of brain, in which there were some enkephalinergic fibers and opiate receptor. But it is unknown whether it participates in the effect of EA on neuron of NRM, a origin of the descending pain inhibitory system. To solve the problem the unit discharge of NRM in the rat was recorded extracellularlywith glass microelectrode, and the effect of EA on it was observed after lesion of bi- lateral NAC with electrolysis. The results were obtained as follows. 1. The effect of EA of "Zusanli" on the excitatory neurons of NRM (n=13) were observed. The increase of spontaneous discharge at o, 5 and 15 min and decrease of nociceptive response at o - 20 and 30 min a- fter EA for 5 mins was statistically significant. 2. After lesion bilateral N. accumbens, the effects of EA on the excitatory neuron in NRM (n=15) were obviously diminished. The spo- ntaneus discharge was only activated at o min, but at 5 - 30 min they all were approached the control level before EA. The nociceptive response was only lower than control at o min, and it was higher than control level at 5～30 min, even it was quite evident at 15～20 min. The data suggest N. accumbens participate in the analgesia induced by activation of EA on NRM neuron. 3. Aftter lesion of bilateral N. accumbens, the effect of injection (i.p.) of fentanyl on NRM neurons had not evident change. Nociceptive response was inhibited, and it was statistically significant at 15, 20 min. But the effect was lower than control group (7 excitatory neurons.) Sponta- neus discharge was also inhibited for a certain degree. The results showed that the influence of N. accumbens on effect of opiates was weaker than EA.