双(7)-他克林对慢性脑缺血老龄鼠海马胶质细胞可塑性及学习记忆功能的干预作用

目的探讨双(7)-他克林(B7T)对持续性低血流灌注脑缺血老年大鼠学习记忆损害及海马胶质细胞可塑性的干预作用。方法雄性SD大鼠30只,随机分为缺血组、对照组和干预组,每组10只。Morris水迷宫实验评估大鼠学习记忆功能,免疫组织化学染色及图像分析技术检测海马CA1区胶质细胞的数量、胞质突起长度等可塑性变化。结果缺血组海马CA1区锥体细胞排列稀疏紊乱,凋亡多见;对照组和干预组锥体细胞排列整齐而密集,凋亡细胞少见。缺血组海马CA1区胶质细胞酸性蛋白(GFAP)阳性细胞和胞质突起长度明显少于对照组和干预组。缺血组逃逸时间明显多于对照组和干预组;缺血组在平台象限停留时间和跨越平台区域的次数明显少于对照组和干预组(P<0.05.P<0.01)。缺血组、对照组及干预组海马CA1区GFAP阳性细胞的数量、胞质突起长度与空间记忆改善呈正相关。结论 B7T可通过促进海马胶质细胞的可塑性改变,改善慢性脑缺血所致的学习记忆认知障碍。胶质细胞的可塑性变化是学习记忆功能改善的重要病理修复机制。     

Cysteine residues 87 and 320 in the amino terminal domain of NMDA receptor GluN2A govern its homodimerization but do not influence GluN2A/GluN1 heteromeric assembly

N-Methyl-D-aspartate receptors（NMDARs） play a central role in various physiological and pathological processes in the central nervous system.And they are commonly composed of four subunits,two GluN1 subunits and two GluN2 or GluN3 subunits.The different subunit compositions make NMDARs a heterogeneous population with distinct electrophysiological and pharmacological properties and thus with different abilities to conduct neuronal activities.The subunit composition,assembly process,and final structure of assembled NMDARs have been studied for years but no consensus has been achieved.In this study,we investigated the role of the amino terminal domain（ATD） of GluN2A in regulating NMDAR assembly.The ATD of GluN2A was first expressed in heterogeneous cells and the homodimer formation was investigated by fluorescent resonance energy transfer and non-reducing SDS- PAGE electrophoresis.Each of the three cysteine residues located in the ATD was mutated into alanine,and the homodimerization of the ATD or GluN2A,as well as the heteromeric assembly of NMDARs was assessed by non-reducing SDS- PAGE electrophoresis,co-immunoprecipitation and immunocytochemistry.We found that two cysteine residues,C87 and C320,in the ATD of the GluN2A subunit were required for the formation of disulfide bonds and GluN2A ATD homodimers.Furthermore,the disruption of GluN2A ATD domain dimerization had no influence on the assembly and surface expression of NMDARs.These results suggest that the two ATD domains of GluN2A are structurally adjacent in fully-assembled NMDARs.However,unlike GluN1,the homomerization of the ATD domain of GluN2A is not required for the assembly of NMDARs,implying that GluN2A and GluN1 play unequal roles in NMDAR assembly.     

卵巢未成熟型畸胎瘤合并抗NMDA受体脑炎2例报告

1 病例资料 病例1为28岁女性患者,已婚已育,因“记忆力减退18 d,加重伴胡言乱语、意识减退1周”收入我院神经内科.患者入院前30 d前出现进行性的记忆力减退、幻听,进而出现哭闹、唱歌、手舞足蹈等异常行为,并伴有呕吐、发热、抽搐等症状.曾于当地医院检查脑电图未见癫痫波,全腹部CT平扫示:盆腔巨大占位,考虑畸胎瘤可能.胸部CT提示:双肺炎症伴双侧胸腔积液.为进一步治疗于2015年6月18日至我院神经内科就诊,拟“颅内感染:继发性癫痢,畸胎瘤?肺部感染”收入院.入院后检查:神志浅昏迷,言语不能;双侧瞳孔直接、间接对光反射均迟钝;眼泪多,口水多,四肢肌张力减弱,肌力不配合,颈软稍微抵抗,Kemig征(+).血清肿瘤标记物CA125 119.8U/mL,SCC-Ag 3.9 ng/mL,血清抗N-甲基-D-天冬氨酸(antiN-methyl-D-aspartate,NMDA)受体抗体阳性,脑脊液抗NMDA受体抗体阳性.妇科超声检查提示:盆腔巨大混合性包块(约12 cm×9 cm),畸胎瘤可能.修正诊断:抗NMDA受体脑炎,畸胎瘤.入院后予以头孢曲松钠抗感染,更昔洛韦抗病毒,氯硝西泮、托吡酯控制癫痫发作,同时予以甲泼尼龙、丙种球蛋白、环磷酰胺免疫抑制,血浆置换2次.患者经治疗后无癫痫持续发作,但仍处于昏睡状态,治疗效果欠满意.经我院妇产科、神经内科、麻醉科专家会诊后于2015年7月10日行全麻下剖腹探查术.术中见:左侧卵巢肿瘤,直径约25 cm,表面有破口,子宫大小正常,活动可,右侧卵巢表面见约2 cm×1.5 cm囊肿,双侧输卵管外观正常.     

右美托咪定预处理抑制脑缺血再灌注时谷氨酸的释放及其受体机制研究

目的  评价右美托咪定预处理对大鼠全脑缺血再灌注损伤时海马谷氨酸（Glu）及其受体NMDAR1（NR1）表达的影响。方法  雄性Wistar大鼠90只,体重250~300 g,采用随机数字表法,将其分为3组（n =30）：假手术组（S组）、全脑缺血再灌注组（I/R组）和右美托咪定组（D组）,采用四血管阻断法制备全脑缺血再灌注损伤模型。D组于全脑缺血前2 h经尾静脉注射右美托咪定3μg/kg,随后以3μg/（kg·h）速率输注120 min,I/R组给予等容量生理盐水。应用Combs评分系统评价大鼠神经运动功能的缺损情况;采用脑微透析技术结合高效液相色谱（HPLC）检测大鼠海马细胞外Glu水平的变化;采用免疫组织化学方法检测海马CA1区NR1蛋白表达。结果  与S组比较,I/R组和D组大鼠平衡木和引绳肌力试验评分下降（P <0.05）,海马细胞外Glu的水平增高（P <0.05）,海马CA1区NR1表达上调（P <0.05）;与I/R组比较,D组大鼠平衡木和引绳肌力试验评分升高（P <0.05）,海马细胞外Glu的水平降低（P <0.05）,海马CA1区NR1表达下调（P <0.05）。 结论 右美托咪定可减轻大鼠全脑缺血再灌注损伤,改善神经运动功能的缺损,其机制与抑制Glu释放和下调NR1表达有关。

     

Antihyperalgesic effects of ginseng total saponins in a rat model of incisional pain

Background

The aim of this study was to assess whether intraperitoneal administration of ginseng total saponins (GTS) has antihyperalgesic effects in a rat model of incisional pain. The proinflammatory responses and reversal of the antihyperalgesic effect of GTS by N-methyl-d-aspartate (NMDA) or naloxone were also evaluated.

Materials and methods

Rats were injected intraperitoneally with 0.9% saline vehicle or various doses of GTS before or after a plantar incision. Paw withdrawal in response to application of the von Frey filament with the lowest bending force marked the mechanical withdrawal threshold (MWT). Blood samples were collected for the assessment of serum interleukin (IL)-1β and IL-6 levels. The IL levels were measured using an enzyme-linked immunosorbent assay kit. Rats were injected intraperitoneally with NMDA or naloxone before the GTS injection to assess the reversal of the antihyperalgesic effect of GTS.

Results

The MWT measured 2 h after the plantar incision increased significantly after the postincision administration of 50, 100, or 200 mg/kg of GTS compared with the MWT at 2 h after plantar incision. The MWT also increased significantly after the preincision injection of 100 or 200 mg/kg of GTS compared with the MWT of the vehicle control. Administration of GTS suppressed the postincision rise in serum IL-1β levels and NMDA inhibited the increase in the MWT compared with GTS alone.

Conclusions

Intraperitoneal administration of GTS before or after surgery induces antihyperalgesic effects in a rat model of incisional pain. The effects on mechanical hyperalgesia may be associated with anti-inflammatory cytokines and NMDA signaling.     

NMDA受体2A亚基磷酸化对幼鼠肝缺血再灌注后脑损伤及远期认知功能障碍的影响

目的 评价肝缺血再灌注 （HIR） 对幼鼠海马以及远期认知功能的影响, 并探讨N-甲基-D-天冬氨酸受体 2A亚基 （NR2A） 磷酸化在其中发挥的作用。方法 健康C57小鼠54只, 2周龄, 体质量6～9 g, 采用随机数字表法分为3组 （n=18）： 假手术组 （S）、 HIR组 （I） 和NR2A抑制剂NVP-AAM077处理组 （N）。建立70% HIR模型, N组于术后连续3 d每天予NVP-AAM077 （10 mg/kg） 腹腔注射。S组和I组以相同方式腹腔注射等体积生理盐水。每组随机取 10只小鼠于术后3 d处死, 分离血清并取脑组织, 酶联免疫吸附测定 （ELISA） 检测血清脑损伤标志物S100β和神经元特异性烯醇化酶 （NSE） 水平, HE染色观察海马组织病理改变, Western blot检测cleaved caspase-3、 NR2A、 p-NR2A Y1325蛋白水平。其余小鼠于术后30 d进行Morris水迷宫实验, 评价远期认知功能。结果 与S组比较, I组与N组血清S100β和NSE水平明显升高, 海马组织水肿, 细胞排列紊乱, cleaved caspase-3、 p-NR2A Y1325蛋白水平升高, 平台所在象限滞留时间缩短 （P＜0.05）; 与I组比较, N组血清S100β和NSE水平降低, 海马神经元病理损伤减轻, cleaved caspase-3、 p-NR2A Y1325蛋白水平下降, 平台所在象限滞留时间明显延长 （P＜0.05）。3组之间NR2A表达水平、 逃逸潜伏期差异无统计学意义 （P＞0.05）。结论 幼鼠HIR可导致脑损伤和远期认知功能障碍, 其机制可能与 NR2A Y1325过度磷酸化介导的兴奋性毒性和细胞凋亡有关。     

Involvement of adenosine and glutamate receptors in the induction of c-fos in the striatum by haloperidol

The psychostimulant drugs amphetamine and cocaine induce the expression of immediate early genes, such as c-fos, in the striatum via D₁ dopamine receptor activation. This occurs primarily in the striato-nigral neurons. Conversely, neuroleptic drugs, such as haloperidol, which block D₂-type dopamine receptors, induce c-fos expression in striatal neurons projecting to the globus pallidus. In order to gain insight into the neurochemical substrates of neuroleptic-induced c-fos expression, we examined the effects of adenosine A₂ and N-methyl-D-aspartate (NMDA) receptor antagonists as well as inhibition of nitric oxide synthase, on haloperidol-induced Fos immunoreactivity in the striatum. While blockade of D₁ receptors had no effect on haloperidol-induced Fos expression, adenosine A₂ receptor antagonists decreased the number of neurons in the striatum expressing haloperidol-induced Fos by half. NMDA receptor antagonists also potently blocked the induction of Fos immunoreactivity by haloperidol, while inhibition of nitric oxide synthase activity had no effect. These results indicate that in the presence of a dopamine D₂ antagonist, Fos expression in striato-pallidal neurons is mediated in part through activation of A₂ receptors by adenosine, and via NMDA receptor activation by glutamate. © 1996 Wiley-Liss, Inc.     

Ammonia metabolism,the brain and fatigue; revisiting the link

This review addresses the ammonia fatigue theory in light of new evidence from exercise and disease studies and aims to provide a view of the role of ammonia during exercise. Hyperammonemia is a condition common to pathological liver disorders and intense or exhausting exercise. In pathology, hyperammonemia is linked to impairment of normal brain function and the onset of the neurological condition, hepatic encephalopathy. Elevated blood ammonia concentrations arise due to a diminished capacity for removal via the liver and lead to increased exposure of organs, such as the brain, to the toxic effects of ammonia. High levels of brain ammonia can lead to deleterious alterations in astrocyte morphology, cerebral energy metabolism and neurotransmission, which may in turn impact on the functioning of important signalling pathways within the neuron. Such changes are believed to contribute to the disturbances in neuropsychological function, in particular the learning, memory, and motor control deficits observed in animal models of liver disease and also patients with cirrhosis. Hyperammonemia in exercise occurs as a result of an increased production by contracting muscle, through adenosine monophosphate (AMP) deamination (the purine nucleotide cycle) and branched chain amino acid (BCAA) deamination prior to oxidation. Plasma concentrations of ammonia during exercise often achieve or exceed those measured in liver disease patients, resulting in increased cerebral uptake. In this article we propose that exercise-induced hyperammonemia may lead to concomitant disturbances in brain function, potentially through similar mechanisms underpinning pathology, which may impact on performance as fatigue or reduced function, especially during extreme exercise.     

孕期酒精暴露对子代大鼠学习记忆及海马N-甲基-D-天冬氨酸受体2B亚基表达的影响

目的 研究孕期酒精暴露对子代大鼠学习记忆及海马N-甲基-D-天冬氨酸(NMDA)受体2B亚基(NR2B)表达的影响.方法 按照随机数字表法,将雌性SD大鼠随机分为正常对照组、饮酒对照组和孕期酒精暴露组,每组各8只;饮酒法建立大鼠孕期酒精暴露模型,子代成年后,采用Y-型迷宫测试子鼠学习记忆成绩;采用聚合酶链反应分析子鼠海马组织NR2B mRNA的表达;采用免疫荧光法检测子鼠海马区NR2B蛋白表达.结果 (1)各组子鼠成年后学习记忆成绩的差异有统计学意义(F=4.566,P＜0.05),孕期酒精暴露组子鼠学习记忆成绩[(43.00±15.33)次]比正常对照组[ (25.13±12.35)次]和饮酒对照组[(26.12±11.95)次]明显下降(P均＜0.05);(2)各组子鼠成年后海马组织中NR2B mRNA表达差异有统计学意义(F=29.795,P＜0.01),孕期酒精暴露组子鼠海马区NR2B mRNA表达(0.97±0.14)较正常对照组(0.52±0.10)和饮酒对照组(0.62±0.12)明显上升(P均＜0.01);孕期酒精暴露组子鼠海马区NR2B蛋白表达明显增加.结论 孕期酒精暴露对子代大鼠的神经损伤可能与NMDA受体亚基NR2B蛋白表达的上调有关.