中缝大核在刺激视上核镇痛中的作用

ROLE OF NUCLEUS MAGNUS RAPHE IN ANALGRESIS CAUSED BY STIMULATING SUPRAOPTIC NUCLEUS

运用核团灌流液的放免测定和高压液相色谱法以及核团内注射拮抗剂，观察了化学刺激下丘脑视上核（ＳＯＮ）对中缝大核（ＮＲＭ）灌流液内催产素（ＯＴ）、精氨酸加压素（ＡＶＰ）和５－羟色胺（５－ＨＴ）含量的影响以及ＮＲＭ内注射ＡＶＰ、５－ＨＴ或ＯＴ受体拮抗剂对痛阈（ＰＴ）的影响。结果表明：ＳＯＮ内注射Ｌ－谷氨酸（Ｌ－Ｇｌｕ）１０μｇ后动物痛阈明显升高，ＮＲＭ灌流液中ＯＴ和５－ＨＴ的含量明显高于对照组水平，ＡＶＰ的含量仅有一过性增加。ＮＲＭ内注射ｏＴ或５－ＨＴ拮抗剂可逆转化学刺激ＳＯＮ引起的镇痛作用；而ＡＶＰ的Ｖ＿(１／２)受体拮抗剂也轻度抑制这种镇痛作用，但Ｖ＿１拮抗剂对此作用无影响。以上结果提示：在刺激ＳＯＮ镇痛中，ＯＴ起着重要作用，Ｌ－Ｇｌｕ刺激ＳＯＮ的ＯＴ细胞释放ＯＴ，作用于ＮＲＭ细胞的ＯＴ受体和Ｖ＿２受体而产生镇痛作用，５－ＨＴ在此过程中也发挥重要作用。

Radioimmunoassay and high pressure liquid chromatography of perfusate from nucleusmagnus raphe(NRM)were used to measure the changes of oxytocin(OT),arginine vasopressin(AVP)and serotonin(5-HTj content,and the effect of injection of OT,AVP or 5-HT antago-nists into N RM on pain threshold(PT)after injection of glutamic acid(L-Glu)into supraopticnucleus(5ON).The results showed that chemical stimulation of SON could elevate the content ofOT and 5-HT in perfusate from N RM,but caused only transient increase in AVP content.OTand 5-HT antagonists could reverse the increase of PT caused by stimulation of SON,and V_(1/2) antagonist of AVP could inhibit the analgesic effect,but V1 antagonist failed toblock this action.These resuIts suggested that OT released by SON might play an important rolein process of analgesia induced by stimulation of SON. OT might act on OT and V_2 receptors ofNRM to produce analgesia and 5-HT receptor might be involved in this action.