中缝隐核对兔奥迪氏括约肌肌电活动的影响

Effect of nucleus raphe obscurus on myoelectric activity of sphincter of Oddi in rabbits

实验用电生理学和微量注射法观察了兔中缝隐核（ＮＲＯ）对奥迪氏括约肌肌电活动的影响。动物禁食但自由饮水，１８～２４ｈ后用乌拉坦（１．０ｇ／ｋｇ）静脉麻醉，用双极康铜丝电极引导奥迪氏括约肌肌电。发现ＮＲＯ内微量注射谷氨酸（３４０ｍｍｏｌ／Ｌ，０．１μｌ）ｓ可使奥迪氏括约肌肌电活动加强，与在ＮＲＯ内微量注射生理盐水或者将谷氨酸（３４０ｍｍｏｌ／Ｌ，０．１μｌ）注射到 ＮＲＯ以外的地方相比，具有显著差异（Ｐ＜０．０１）； ＮＲＯ内微巨注射 Ｎ－ｍｅｔｈｙｌ－Ｄ－ａｓｐａｒｔａｔｅ（ＮＭ－ＤＡ）受体阻断剂氯胺酮（１８０ｍｍｏｌ／Ｌ，０．１μｌ），可消除谷氨酸的效应，而将微量非 ＮＭＤＡ受体阻断剂 ＣＮＱＸ（２ｍｍｏｌ／Ｌ，０．１μｌ）注入ＮＲＯ，可使奥迪氏括约肌肌电加强，且不能阻断谷氨酸的作用；将微量ＧＡＢＡ（１ｍｏｌ／Ｌ，０．１μｌ）注射到ＮＲＯ内，可明显抑制奥迪氏括约肌肌电的发生。外周应用Ｍ－受体阻断剂阿托品（０．２ｍｇ／ｋｇ）或双侧颈部迷走神经切断，可阻断微量谷氨酸注射到 ＮＲＯ内所引起的效应；静脉注射α－受体阻断剂酚妥拉明（１．５ ｍｇ／ｋｇ）、心得安（１．５ｍｇ／ｋｇ）或自Ｔ３－４处切断脊髓。

The aim of the present study was to investigate the role of nucleus raphe obscurus (NRO) in reg-ulating the motility of sphincter of Oddi (SO). After fasting about 18-24 h, the rabbits were anesthetized with urethane (1.0 g/kg) , and the myoelectric signals of SO were induced by a pair of copper electrodes in-serted into the subscra. The results of microinjecton of various drugs into NRO are as follows. After glutamate (340 mmol/L, 0.1μl) was injected, activity of SO was excited. With microiniection of GABA (1 mol/L, 0. 1μl)，the spike burst of SO was inhibited. Following micruinjection of ketamine (180 rnrnol/L, 0. lμl), a kind of N-methyl-D-aspartate (NMDA) receptor antagonist, SO motility was inhibited and the effect of glutamate was abolished. Injection of 6-cyano-7-nitmquinoxaline-2,3-dione (CNQX) (2 mmol/L, 0.1 μ1), a non-NMDA receptor antagonist, also excited the myoelectric activity of SO, but did not inhibit the effect of gluta-mate. The effect of glutamate was abolished by intravenous injection of atropine (0.2 mg/kg) or bilateral vago-tomy,but not by injection of phentolamine (1 .5 mg/kg) or propronalol (1 .5 mg/kg), or by transection of the spinal cord.The above results indicate that NRO mediation of SO activity is due to the effect of glutamate on the NMDA receptors in the nucleus, the output of which is sent through vagal nerve and peripheral M choliner-gic receptor to excert excitation of gallbladder motility.