Meynert核毁损后大鼠海马结构内生长抑素阳性神经元的变化

Changes in somatostatin-immunopositive neurons of the hippocampal formation in the Meynert-lesioned rat

目的观察Meynert核毁损后大鼠海马结构内生长抑素（SS）阳性神经元变化，探讨ss参与学习记忆的机制。方法以海人酸（1肚g／每侧）毁损双侧Meynert（NBM）核建立学习记忆障碍模型，用避暗回避实验进行行为学检测，免疫组织化学染色后光镜下观察并计数海马结构内SS阳性神经元。结果1．NBM受损后大鼠记忆力明显下降，与正常组比较具有显著性差异；2．NBM受损后各组海马结构内ss阳性神经元数鼍明显减少，与正常组比较具有高度显著性差异。细胞形态的改变主要表现为胞质着色减弱，阳性突起变短.结论NBM损毁后大鼠海马结构内sS阳性神经元数帚显著减少，此过程参与了NBM毁损导致的大鼠学习记忆障碍。

Objective To investigate the changes of somatostatin （SS）-immunopositive neurons in the hippocampal formation in Meynert（ NBM）-lesioned rat and to make a preliminaly analysis of the mechanism of SS participating in learning and memory. Methods In this study, the memory dysfunction model was established by the microinjection of kainic acid （KA） into the bilateral NBM. The passive avoidance task was used to estimate the degree of memory dysfunction. After 1-4 weeks survival, brain sections were stained by immunohistochemical technique to show the SS-immunopositive neurons. Then the SS- immunopositive neurons were counted with an optic microscope. Results Lesions of NBM could remarkably disrupt memory continuance compared with the normal group. There was a highly significant difference between the NBM-lesioned group and the normal group in the number of SS-positive neurons of hippocampa] formation（ P 〈 0.01 ）. There were a few changes of lesion in celiular morphology, which present as the slightly illegible cell outline and the shortening or disappeanig processes. Conclusion SS-positive neurons in the hippocampal formation decreased significantly in the NBM-destroyed rat and it may have a role in the memory dysfunction to a certain extent.