尾核不但参与躯体运动的调节

也和感觉机能有关。我们以往的工作表明

刺激大鼠尾核头部能够激活大多数中缝大核(NRM)神经元的自发放电和抑制其伤害性刺激诱发的反应;在尾核头部前区微量注射吗啡也能明显地抑制NRM神经元的伤害感受性反应;电针“足三里”穴激活NRM神经元自发放电和抑制伤害感受性反应的效应在电解损毁双侧尾核头部后明显降低。这些结果均表明

尾核头部参与对疼痛的调节和控制;其效应至少有一部分是通过脑Experiments were performed on the male rats (250-350g) anesthetized with urethane (1.0g/kg i. p). The unit discharge of nucleus raphe magnus (NRM) was extracellularly recorded with glass microelectrode. The influ- ences of naloxone and DA injected in the head of caudate nucleus on effect of electroacupuncture (EA) upon NRM neurons were observed. 1. Influence of naloxone microinjected in the head of caudate nucleus on effect of EA The firing rate of major NRM neurons was not altered and nociceptive response was slightly increased by the operation itself of microinjectng na- loxone in the head of caudate nucleus (n=10). But after injection of na- loxone (5μg/ 1μl on each side

n=17) into the caudate nucleus

the effect of EA on NRM neurons was clearly attenuated. The naloxone administrarion group was compared with the control group injected saline in the caudate nucleus (n=15)

the reduction of inhibition of EA on the nociceptive re- sponse was statistically significant during 1-25 min. These results suggested that the effect of EA on NRM neurons could be abolished by local injecti- on of naloxone into the head of caudate nucleus and that OLS in this re- gion was involved in the acupuncture analgesia. 2. Influence of DA microinjected in the head of caudate nucleus on effect of EA The firing rate and its nociceptive response of major NRM neurons we- re unaffected by the operation itself of microinjecting DA into the caudate nucleus (n=12). The effect of EA on NRM neurons was not evidently attenuated following local injection of DA (4μg/1μl on each side. n=16) into the caudate nucleus

but the post-effect of EA was obviously shortened by DA. Compared with control group injected saline

the difference of noci- ceptive response in both was satistically significant during 10-15 min. These result suggested that the effect of EA on NRM neurons could be shortened by local injection of DA into the head of caudate nucleus and DA in this region played some antagonism on acupuncture analgesia.