尾核阿片μ受体参与电针及皮层SmⅠ区对束旁核伤害性反应的抑制

OPIOID μ RECEPTORS IN CAUDATE NUCLEUS CONTRIBUTE TO ELECTROACUPUNCTURE AND Sm ⅠGENERATING INHIBITION ON NOCICEPTIVE RESPONSES OF Pf NEURONS *

为探索尾核（ｃａｕｄａｔｅｎｕｃｌｅｕｓ，Ｃｄ）是否参与电针及皮层体感运动Ⅰ区（ｓｅｎｓｏｒｉｍｏｔｏｒａｒｅａⅠｏｆｔｈｅｃｅｒｅｂｒａｌｃｏｒｔｅｘ，ＳｍⅠ）对束旁核（ｐａｒａｆａｓｃｉｃｕｌａｒｎｕｃｌｅｕｓ，Ｐｆ）神经元伤害性反应的调节，以及Ｃｄ中阿片受体是否参与并通过何种受体参与这一调节，本实验用Ｃｄ头部化学毁损及微量注射阿片受体拮抗剂的方法，观察到Ｃｄ毁损前电针及兴奋皮层均可抑制Ｐｆ的伤害性反应，而毁损后这种抑制效应消失；注射纳洛酮或阿片μ受体拮抗剂βＦＮＡ后，电针及兴奋皮层ＳｍⅠ区对Ｐｆ伤害性反应的抑制作用被取消，而分别注射δ和κ受体拮抗剂ＩＣＩ１７４，８６４和ｎｏｒＢＮＩ则不产生影响。基于已证明大脑皮层参与电针对Ｐｆ伤害性反应的调节，本结果提示：Ｃｄ参与针刺镇痛中皮层ＳｍⅠ区对Ｐｆ神经元伤害性反应的抑制，Ｃｄ中阿片肽主要通过μ受体参与抑制作用。

The present experiments aimed to investigate whether the caudate nucleus (Cd) was involved in cortical sensorimotor area Ⅰ(Sm Ⅰ) generating descending modulation of the parafascicular nucleus (Pf) in acupuncture analgesia (AA),and what type of opiate receptors in Cd were involved.It was found that nociceptive responses of Pf neurons could be inhibited by electroacupuncture (EA) and excitation of Sm Ⅰ before lesion of Cd,but not after lesion.After microinjection of naloxone of β-FNA,the specific antagonist for opioid μ receptors ,into Cd ,the inhibitory effect of EA of activation of Sm Ⅰ on nociceptive responses of the Pf neurons was abolished,but it was not influenced by microinjection of nor-BNI and ICI174,864,the specific antagonists for opioid κ and δ receptors,respectively,Together with our previous findings that EA could activate cortical neurons to participate in descending modulation of activities of pf neurons,the present results suggest that Cd is associated with Sm Ⅰ generating descending inhibition on nociceptive responses of Pf neurons in AA,and it is most likely that opiates in Cd may be involved in this inhibition through μ,but not κ of δ receptors.