去传入神经引起大鼠延髓后角P物质、胆囊收缩素、神经降压肽、亮-脑啡肽变化机制的探讨

STUDY ON THE MECHANISM OF CHANGES OF SUBSTANCE P, CHOLECYSTOKININ, NEUROTENSIN, LEUCIN-ENKEPHALIN WITHIN THE RAT MEDULLARY DORSAL HORN BY DEAFFERENTATION

去传入神经可引起后角一些肽类变化和含肽的大颗粒小泡以胞吐的形式在非突触部位释放。为了探讨这一作用机制,本文切除一侧刚髭部皮肤,应用免疫组化方法观察并定量分析术后不同时间延髓后角浅层SP、CCK、NT、L-ENK阳性纤维的变化及利多卡因对后角浅层SP的影响。结果显示:术后1小时,延髓后角浅层SP损伤侧较对照侧升高,第3～7天未见显著性减少或升高,第8天开始脱失(P<0.05),第14天脱失更甚,第30天开始恢复,第90～120天基本恢复。CCK变化基本同SP。NT、L-ENK术后不同时间(7～120天),两侧比较未见显著性差异(P>0.05)。应用和多卡因后,后角浅层SP损伤侧较对照侧未见明显减少(P>0.05)。根据上述结果,本文推测:去传入神经导致延髓后角浅层神经肽的变化,可能是神经损伤区(神经瘤或再生芽)产生异常电活动,引起延髓后角浅层神经肽释放的结果。

Previous studies have demonstrated that the changes of neuropeptides may be induced and neuropeptides containing large granular vesicles may release their contents by exocytosis at nonsynaptic sites within the dorsal horn of spinal cord and medulla oblongata of rat by deafferentation. In order to study the mechanism, we used immunohistochemistry to examine the changes of immunoreactive fibers of substance P (SP), cholecystokinin (CCK), neurotensin (NT), leucinenkephalin (L-ENK) and the effect of lidocaine on SP in the superficial dorsal horn of medulla oblongata at different survival times after a unilateral skin excision in the vibrissae area. Some of the quantitative observations were carried out with an automated image analysis system. The results indicated that SP immunoreactive fibers were increased slightly in the superficial dorsal horn of lesion side as compared with the contralateral control 1 hour after operation. From the 3rd to the 7th day no change was found with SP staining. The depletion of SP started on the 8th day (P<0.05) and further depletion was seen on the 14th day. SP staining started to recover partly on the 30 th day. The difference of SP staining between two sides (lesion and control sides) was gradualy diminished in the 90th-120th day. The changes of CCK were similar to those of SP. NT and L-ENK on the ipsilateral superficial dorsal horn to the lesionarea from the 7th to the 120th day after operation were not significantly increased or decreased (P>0.05).SP staining was not remarkably reduced in the superficial dorsal horn of lesion side between the 8th and the 14day after the injection of 1％ lidocaine. Our findings suggested that the changes of neuropeptides in the superficial dorsal horn of medulla oblongata induced by deafferentation may be due to the abnormal neuronal activity from the neuronal lesion area (neuroma) resulting in the release of neuropeptides.