海马NDMA受体与胃肌间神经丛NOS神经元分布在慢性应激性胃运动变化中的关系

 目的 探讨慢性应激对大鼠胃功能和胃肠神经系统的影响，并分析其海马谷氨酸（Glu）离子型受体机制。方法 通过建造慢性应激性抑郁模型大鼠，结合脑立体定位及微量注射Glu和N-甲基-D-天冬氨酸（NMDA）受体阻断剂MK-801，对实验鼠进行糖水偏爱等行为学检测、胃内压记录及胃内在神经丛的一氧化氮合酶(Nitric oxide synthase，NOS)阳性神经元表达的组织化学检测。结果 慢性不可预见性温和应激（CUMS）动物表现出抑郁样行为，且胃运动减弱；海马注射NMDA受体阻断剂MK-801，可以反转CUMS的效应；海马注射Glu，能增加游泳不动时间，但对胃运动无影响。CUMS使胃肌间神经丛NOS阳性神经元数量减少（73.74±16.38/LPF，P<0.05），神经节数量减少（4.25±1.34/LPF， P<0.05），但每个神经节内神经元数量明显增加（6.55±2.37，P<0.05）；海马注射MK-801，能改善CUMS引起的神经节数量减少的现象。结论 慢性应激诱发的抑郁样行为与海马Glu 及其NMDA受体有关，而胃活动的减弱可能与海马NMDA受体变化影响胃肌间神经丛NOS神经元分布格局有关

Relationships between hippocampal NMDA receptor and NOS positive neurons in myenteric nerve plexus in stomach of CUMS rats

Objective To investigate the involvement of hippocampal glutamate and NMDA receptor in the effect of CUMS on gastric function and enteric nervous system(ENS).Methods Chronic unpredictability mild stress(CUMS)-induced depression model was established in SD rats,intra-hippocampal microinjections of Glu and non-competitive antagonist of N-methyl-D-aspartic acid(NMDA) receptor(MK-801) were respectively adopted by rat brain stereotaxic coordinates.The behavioral observations were conducted by sucrose preference test and forced swimming test.The intra-gastric pressure was recorded and the expression of Nitric oxide synthase(NOS) positive neurons in myenteric nerve plexus in stomach was detected as well.Results CUMS rats showed depression-like behavioral changes and weaker gastric motility as compared to control.Pretreated with MK-801 could reverse these CUMS effect,while microinjection of Glu,instead of CUMS,could increase the duration of immobility in forced swimming test,but has no effect on gastric motility.CUMS rats had lower expression of NOS positive neurons [(73.74±16.38)/LPF,P<0.05] and positive ganglions number[(4.25±1.34)/LPF,P<0.05] compared with control,but the number of NOS positive neurons in every ganglion was increased(6.55±2.37,P<0.05).Pretreated with MK-801 may rescue the decline of the number of positive ganglions.Conclusion CUMS may regulate the activity of NMDA receptor in hippocampus,change the configuration of NOS positive neurons in ENS and weaken the gastric motility.While the effects of CUMS on depression-like behavioral changes due to both Glu and NMDA receptor in hippocampus.