Expression of N-methyl-D-aspartic acid 2A-B and 2B receptors in anterior thalamic nucleus and subiculum complex of rats

BACKGROUND：Glutamate acid ionotropic receptor N-methyl-D-aspartic acid （NMDA） takes part in long-term potentiation, thereby influencing the process of learning and memory. OBJECTIVE： To verify expression of NMDA 2A/B and 2B receptors in the anterior thalamic nucleus and subiculum complex of rats. DESIGN, TIME AND SETTING： A single-sample observation was performed at Department of Anatomy in Dalian Medical University （Dalian, Liaoning, China） from April to September in 2007. MATERIALS： Ten adult Wistar rats were used for this study, as well as rabbit anti-NMDA 2A/B and 2B antibodies. METHODS： The rats were anesthetized and perfused, followed by brain resection and coronal sectioning of the brain tissue. A 1：3 series was selected for immunohistochemistry, using antibodies specific to NMDA 2A/B and 2B receptors. Photos were taken using the Nikon image analysis system. MAIN OUTCOME MEASURES： Expression and distribution of immunohistochemistry staining of NMDA 2A/B and 2B receptor subunits. RESULTS： There were a large number of NMDA 2A/B and 2B receptor-positive neurons distributed throughout the anterior dorsal thalamic nucleus. In the anterior ventral thalamic nucleus, distribution of positive neurons was rare, staining intensity was lighter, and cell bodies were smaller compared with the anterior dorsal thalamic nucleus. In the subiculum complex, staining intensity of NMDA 2A/B and 2B-positive neurons was weakest in the molecular layer and stronger in the pyramidal layer, in particular the region with large cell bodies adjacent to the molecular layer. In the multiform layer, more positive neurons of various sizes were detected. CONCLUSION： NMDA 2A/B and 2B receptor subunits were richly distributed in the anterior thalamic nucleus, with a small difference existing between the anterior dorsal nucleus and anterior ventral nucleus. These neurons were also differentially distributed within the three layers of the subiculum complex.

Basal Forebrain Cholinergic Innervation Induces Depression-Like Behaviors Through Ventral Subiculum Hyperactivation

Malfunction of the ventral subiculum(vSub),the main subregion controlling the output connections from the hippocampus,is associated with major depressive disorder(MDD).Although the vSub receives cholinergic innervation from the medial septum and diagonal band of Broca(MSDB),whether and how the MSDB-to-vSub cholinergic circuit is involved in MDD is elusive.Here,we found that chronic unpredictable mild stress(CUMS)induced depression-like behaviors with hyperactivation of vSub neurons,measured by c-fos staining and whole-cell patch-clamp recording.By retrograde and anterograde tracing,we confirmed the dense MSDB cholinergic innervation of the vSub.In addition,transient restraint stress in CUMS increased the level of ACh in the vSub.Furthermore,chemogenetic stimulation of this MSDB-vSub innervation in ChAT-Cre mice induced hyperactivation of vSub pyramidal neurons along with depression-like behaviors;and local infusion of atropine,a muscarinic receptor antagonist,into the vSub attenuated the depression-like behaviors induced by chemogenetic stimulation of this pathway and CUMS.Together,these findings suggest that activating the MSDB-vSub cholinergic pathway induces hyperactivation of vSub pyramidal neurons and depression-like behaviors,revealing a novel circuit underlying vSub pyramidal neuronal hyperactivation and its associated depression.

Low-frequency Stimulation at the Subiculum Prevents Extensive Secondary Epileptogenesis in Temporal Lobe Epilepsy

Secondary epileptogenesis is characterized by increased epileptic susceptibility and a tendency to generate epileptiform activities outside the primary focus.It is one of the major resultants of pharmacoresistance and failure of surgical outcomes in epilepsy,but still lacks effective treatments.Here,we aimed to test the effects of low-frequency stimulation(LFS)at the subiculum for secondary epileptogenesis in a mouse model.Here,secondary epileptogenesis was simulated at regions both contralateral and ipsilateral to the primary focus by applying successive kindling stimuli.Mice kindled at the right CA3 showed higher seizure susceptibilities at both the contralateral CA3 and the ipsilateral entorhinal cortex and had accelerated kindling processes compared with naive mice.LFS at the ipsilateral subiculum during the primary kindling progress at the right CA3 effectively prevented secondary epileptogenesis at both the contralateral CA3 and the ipsilateral entorhinal cortex,characterized by decreased seizure susceptibilities and a retarded kindling process at those secondary foci.Only application along with the primary epileptogenesis was effective.Notably,the effects of LFS on secondary epileptogenesis were associated with its inhibitory effect at the secondary focus through interfering with the enhancement of synaptic connections between the primary and secondary foci.These results imply that LFS at the subiculum is an effective preventive strategy for extensive secondary epileptogenesis in temporal lobe epilepsy and present the subiculum as a target with potential translational importance.

吗啡相关环境线索调节腹侧海马下托区谷氨酸和γ-氨基丁酸的释放

目的研究吗啡相关环境线索能否调节腹侧海马下托区谷氨酸和γ-氨基丁酸的释放。方法采用条件性位置偏爱和条件性位置厌恶模型分别建立与吗啡奖赏、厌恶相关的环境线索。采用微透析和高效液相荧光检测法测定上述环境线索下大鼠腹侧海马下托区细胞外谷氨酸和γ-氨基丁酸的浓度。结果吗啡奖赏相关环境线索引起腹侧海马下托区细胞外γ-氨基丁酸浓度下降了约11%,吗啡厌恶相关的环境线索引起腹侧海马下托区细胞外的谷氨酸浓度增加了约230%。结论吗啡相关的环境线索可能通过不同的神经环路调节腹侧海马下托区神经递质的释放。

雌激素替代治疗大鼠海马结构PKC阳性细胞的变化

目的 :观察雌性大鼠行去势后以及雌激素替代治疗海马结构蛋白激酶C ( proteinkinaseC ,PKC)阳性细胞的变化 ,通过该模型研究绝经期后女性情绪烦躁、记忆下降等神经精神症状的分子机制。方法 :将大鼠分为对照组、去势 3个月组和去势后雌激素替代治疗 3个月组 ,用免疫组织化学方法检测海马结构PKC阳性细胞的变化。结果 :PKC阳性细胞主要分布于下托和齿状回的颗粒层 ,其中齿状回内的阳性细胞较下托的多。去势 3个月组与对照组相比 ,齿状回内的PKC阳性细胞没有显著性减少 (P >0 .0 5 ) ,下托PKC阳性细胞显著减少 (P <0 .0 5 ) ;雌激素治疗组与对照组相比 ,下托细胞数量有所减少 ,但无显著性差异 (P >0 .0 5 )。结论 :海马结构下托PKC阳性细胞的减少可能在绝经后女性情绪烦躁、记忆下降等症状中起重要的作用。

Calbindin-D28k在出生前人海马本部及下托神经元的表达及其变化

本实验采用免疫组织化学方法研究了１３～３８ 周人胎儿海马本部及下托含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 神经元的分布和发育。结果表明：在１３～１４ 周时，许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞可见于ＣＡ１ 区锥体细胞层中部及深部，随着胎龄增大，ＣＡ１ 区含Ｃａｌ－ｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞的数量及密度逐渐下降，最终消失，并且这种下降及消失首先从含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞区浅部开始，然后向深部推进；在１３～２８ 周期间，ＣＡ２ 和ＣＡ３ 区也有许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞，但至３２ 周以及其后，ＣＡ３ 和ＣＡ２ 区则不见含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞，仅在ＣＡ２ 与ＣＡ１ 交界区见到少量弱染的含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞。此外，在２８～３８ 周期间，ＣＡ３ 和ＣＡ２ 区锥体细胞层周围可见许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 的苔藓纤维，其密度随胎龄增大而增加。１４～３８ 周期间，许多含Ｃａｌｂｉｎｄｉｎ－Ｄ２８ｋ 的锥体细胞也出现于下托锥体细胞层全层及前下托锥体细胞层浅部（细胞岛区）及中部。这些区域含Ｃａｌ－ｂｉｎｄｉｎ－Ｄ２８ｋ 锥体细胞的数量及染色强度在１４～２４

吗啡依赖大鼠伏隔核与海马腹侧下托放电频率的改变

目的:用胞外记录的方法分别观察伏隔核和海马腹侧下托对吗啡的反应性,探讨其在药物心理依赖形成过程中所处的地位。方法:吗啡依赖大鼠及正常大鼠各10只,依照大鼠脑立体定向图谱,将电极下至将要记录核团附近,依次注射吗啡、纳洛酮,观察各核团对药物的反应性。结果:吗啡依赖组大鼠伏隔核放电频率从15Hz±s3Hz变化至<3Hz甚至放电中断,正常组大鼠从6Hz±s2Hz变化至0·5-3Hz;吗啡依赖组大鼠海马腹侧下托放电频率7Hz±s2Hz变化不明显,正常组放电频率6Hz±s2Hz变化不明显。结论:在药物心理依赖形成过程中,伏隔核发生了较明显的变化,而海马腹侧下托变化不明显。

眼镜蛇毒对成年大鼠下托Nestin表达的影响

目的探讨眼镜蛇毒对成年大鼠下托巢蛋白(Nestin)阳性神经细胞表达的影响。方法采用免疫组织化学方法,观察并比较Nestin阳性细胞在眼镜蛇毒组、生理盐水组、正常对照组大鼠下托的表达。结果眼镜蛇毒组大鼠下托Nestin阳性神经细胞比生理盐水组、正常对照组表达明显增强(P<0.01)。结论眼镜蛇毒对大鼠下托Nestin表达有上调作用。

大鼠隔-下托投射定位关系的确定

目的:研究隔-下托投射定位关系。材料与方法:1％ WGA-HRP与10％ HRP混合液用微量注射器注射入大鼠背侧下托,存活36h,取材。海马切片用H_2O_2-DAB显色确定注射点位置,隔区切片用TMB显色显示逆行标记神经元。结果:HRP逆行标记细胞主要出现于同侧内侧隔核(MS)和斜带核(NDBV),Bregma点0.70mm～0.48mm的平面上达到高峰。对侧MS和NDBV仅见少量逆行标记神经元。结论:下托接受同侧MS-NDBV大量神经元投射,其中背海马下托前部与MS-NDBV的中部存在明显定位关系。

Alzheimer病的MR诊断价值探索

目的:探讨MR在Alzheimer病的临床诊断价值。材料与方法:将80例已临床诊断为Alzheimer病的病例编为试验组,另将80例临床排除老年性痴呆诊断的病例编为对照组,将两者的颅脑各部分脑萎缩的情况进行对照研究。结果:与对照组相比,实验组病例的海马结构、海马旁结构及胼胝体有较明显萎缩。结论:MR检查在Alzheimer病的诊断方面具有不可低估的价值。

Subicular pyramidal neurons gate drug resistance in temporal lobe epilepsy

OBJECTIVE To understand the underlying mechanisms of drug resistant temporal lobe epilepsy(TLE).METHODS In vivo and vitro electrophysiology,optogenetics and chemogenetics were used in a classic multi-drug resistant TLE model.RESULTS Subicular pyramidal neuron activity was not inhibited by the anti-epileptic drug phenytoin in drug resistant rats.This phenomenon was specific to the subiculum,but did not involve surrounding temporal lobe regions.Selective inhibition of subicular pyramidal neurons by both optogenetics and chemogenetics reversed drug resistance.In contrast,selective activation of subicular pyramidal neurons directly induced drug resistance in drug responsive rats.Furthermore,long-term low frequency stimulation at the subiculum,which is clinically feasible,inhibited the activity of subicular pyramidal neurons and reversed drug resistance.CONCLUSION Subicular pyramidal neurons might be a key ″ switch″ mediating drug resistance in TLE and represent a new potential target for more precise treatment of drug resistant TLE.

大白鼠海马下托的皮质和皮质下核团的传入纤维联系——HRP法研究

使用HRP逆行轴浆运输技术观察了大白鼠海马下托的皮质和皮质下核团传入纤维联系。向腹侧下托和背侧下托投射的皮质区包括:Brodmann’s 28、27、35、13、25、51b区前份和29区后份;向下托投射的皮质下核团包括:Broca’s斜角带、内侧隔核、上乳头体核,下乳头体丘脑束核、中缝背核、正中中缝核、蓝斑核、丘脑连合核,皮质杏仁核及对侧海马结构的CA_(3)、CA_(4)亚区。这些结果表明,大白鼠海马下托是皮质向海马结构投射的主要接受区。但是在实验中没有观察到新皮质区向下托的纤维投射。在啮齿类动物这个进化等极上,新皮质区似乎尚未与海马结构建立纤维联系。实验结果还说明,皮质下核团向海马下托和CA亚区均有纤维投射,但是向腹侧下托投射的皮质下核团数目更多。

内镜下后、下鼓室精细解剖及变异观察

目的探讨国人后、下鼓室各骨嵴及隐窝之间的毗邻关系及存在形态,为临床提供解剖学数据。方法遴选80例中耳(成人灌注新鲜冰冻尸头20具和耳内镜手术40例),在0°和30°耳内镜下经外耳道进入中耳,对后、下鼓室相关区域进行解剖和观察,记录后、下鼓室各骨嵴及隐窝形态并制成图表。结果①岬小桥出现率为62.50%(50/80),实性骨嵴、桥状骨嵴占比分别为52.50%、10.00%;②岬下脚出现率为52.50%(42/80),实性骨嵴、桥状骨嵴占比分别为41.25%、11.25%;③岬末脚出现率为52.50%(42/80),实性骨嵴、桥状骨嵴占比分别为46.25%、6.25%;④上述结构变异使后鼓室窦及鼓室窦毗邻关系分为经典型(50.00%)、融合型(47.50%)、分隔型(1.25%)、限制型(1.25%);⑤鼓索嵴、椎体嵴、茎突嵴三者出现占比分别为67.50%(54/80)、75.00%(60/80)、57.50%(46/80)。结论耳内镜可以清晰地显露显微镜难以观察的解剖结构,国人后、下鼓室部分骨嵴及隐窝呈现不同的形态。