The human δ2 glutamate receptor gene is not mutated in patients with spinocerebellar ataxia

The human glutamate receptor delta 2 gene （GRID2） shares 90%homology with the orthologous mouse gene. The mouse Grid2 gene is involved with functions of the cerebellum and sponta-neous mutation of Grid2 leads to a spinocerebellar ataxia-like phenotype. To investigate whether such mutations occur in humans, we screened for mutations in the coding sequence of GRID2 in 24 patients with familial or sporadic spinocerebellar ataxia and in 52 normal controls. We de-tected no point mutations or insertion/deletion mutations in the 16 exons of GRID2. However, a polymorphic 4 nucleotide deletion （IVS5-121_-118 GAGT） and two single nucleotide polymor-phisms （c.1251G〉T and IVS14-63C〉G） were identiifed. The frequency of these polymorphisms was similar between spinocerebellar ataxia patients and normal controls. These data indicate that spontaneous mutations do not occur in GRID2 and that the incidence of spinocerebellar ataxia in humans is not associated with GRID2 mutation or polymorphisms.     

Two types of auditory glutamatergic synapses and their implications for repairing damaged central auditory pathways

<正>For the mammalian brain to process and decipher the rich panoply of sounds that abound in the world,nature has evolved an elegant collection of neural circuits dedicated to this task.Indeed,the complexity,variety and number of neural pathways devoted to computing auditory information is unique among sensory modalities(Kaas,2008).After     

Effects of diazepam on glutamatergic synaptic transmission in the hippocampal CA1 area of rats with traumatic brain injury

The activity of the Schaffer collaterals of hippocampal CA3 neurons and hippocampal CA1 neurons has been shown to increase after fluid percussion injury. Diazepam can inhibit the hyperexcitability of rat hippocampal neurons after injury, but the mechanism by which it affects excitatory synaptic transmission remains poorly understood. Our results showed that diazepam treatment significantly increased the slope of input-output curves in rat neurons after fluid percussion injury. Diazepam significantly decreased the numbers of spikes evoked by super stimuli in the presence of 15 μmol/L bicuculline, indicating the existence of inhibitory pathways in the injured rat hippocampus. Diazepam effectively increased the paired-pulse facilitation ratio in the hippocampal CA1 region following fluid percussion injury, reduced miniature excitatory postsynaptic potentials, decreased action-potential-dependent glutamine release, and reversed spontaneous glutamine release. These data suggest that diazepam could decrease the fluid percussion injury-induced enhancement of excitatory synaptic transmission in the rat hippocampal CA1 area.     

Overexpression of C-terminal fragment of glutamate receptor 6 prevents neuronal injury in kainate-induced seizure via disassembly of GluR6-PSD95-MLK3 signaling module

Our previous study showed that when glutamate receptor （GluR）6 C terminus-containing peptide conjugated with the human immunodeficiency virus Tat protein （GluR6）-9c is delivered into hippocampal neurons in a brain ischemic model, the activation of mixed lineage kinase 3 （MLK3） and c-Jun NH2-terminal kinase （JNK） is inhibited via GluR6-postsynaptic density protein 95 （PSD95）. In the present study, we investigated whether the recombinant adenovirus （Ad） carrying GluR6c could suppress the assembly of the GluR6-PSD95-MLK3 signaling module and decrease neuronal cell death induced by kainate in hippocampal CA1 subregion. A seizure model in Sprague-Dawley rats was induced by intraperitoneal injections of kainate. The effect of Ad- Glur6-9c on the phosphorylation of INK, MLK3 and mitogen-activated ldnase kinase 7 （MKK7） was observed with western immunoblots and immunohistochemistry. Our findings revealed that overexpression of GluR6c inhibited the interaction of GluR6 with PSD95 and prevented the kainate-induced activation of INK, MLK3 and MKK7. Furthermore, kainate-mediated neuronal cell death was significantly suppressed by GluR6c. Taken together, GluR6 may play a pivotal role in neuronal cell death.     

U0126对谷氨酸神经毒性损伤模型大鼠的脑保护作用

目的 探索U0126对脑组织谷氨酸神经毒性的保护作用及可能机制。方法 健康成年雄性SD大鼠皮层注射 N-甲基-D-天冬氨酸（NMDA）建立脑组织谷氨酸神经毒性模型。首先,采用不同浓度 NMDA（50、100、200mmol/L）及处理不同时间（3、6、12、24 h）筛选最佳的建模条件。根据选定的最佳条件,实验设对照组、MAPK/ERK1/2抑制剂U0126单独处理组（2 g/L）、NMDA组（200 mmol/L）、不同浓度（0.5、1、2 g/L）U0126联合NMDA处理组。各组处理24 h后处死动物,脑组织切片后行HE染色组织评价损伤;蛋白质印迹法检测损伤部位环氧合酶-2（COX-2）、诱导型一氧化氮合酶（iNOS）、Caspase-3（活化形式）及磷酸化ERK1/2（p-ERK1/2）表达水平,确定U0126在脑组织谷氨酸神经毒性损伤中的保护作用。结果 （1）NMDA以时间和浓度依赖的方式导致大鼠皮层兴奋毒性损伤,激活MAPK/ERK1/2信号通路,加重脑组织损伤,选取200 mmol/L NMDA处理24 h进行建模。（2）与对照组相比,NMDA组脑损伤部位COX-2、iNOS、Caspase-3（活化形式）、p-ERK1/2表达明显增加。U0126+NMDA处理组与NMDA组相比,COX-2、NOS、Caspase-3（活化形式）、p-ERK1/2表达水平随U0126浓度升高而降低,脑损伤的面积显著减小。结论 U0126对大鼠皮层谷氨酸神经毒性损伤具有保护作用,其机制可能与抑制ERK1/2激活及其下游的炎症、凋亡信号途径有关。     

铅对原代培养星形胶质细胞谷氨酸转运体的影响

目的探讨铅暴露对星形胶质细胞(AS)中GLAST和GLT-1蛋白表达及转运体功能的影响。方法取出生1~3 d Wistar大鼠的仔鼠星形胶质细胞进行原代培养,以胶质纤维酸性蛋白(GFAP)染色鉴定细胞纯度后,进行0(对照组)、50、100、200及400μmol/L乙酸铅染毒,染毒时间为72 h。倒置显微镜下观察细胞形态并采集图像;以AlamarBlue法检测细胞活力;以Western blot法检测GLAST和GLT-1蛋白的表达;以同位素标记法测定谷氨酸转运体功能。结果 50和100μmol/L铅暴露组的细胞形态与对照组相比,未见明显改变;200μmol/L铅暴露72 h后,少量细胞开始脱壁,细胞间隙增大;400μmol/L铅暴露组细胞变大,突起变短或消失,脱壁细胞数量明显增多。与对照组相比,各浓度铅暴露组的AS活力均降低(P0.05),100、200和400μmol/L铅暴露组的GLT-1蛋白含量下降(P0.05),但各浓度铅暴露组的GLAST蛋白含量无显著改变。100、200和400μmol/L铅暴露组的3H-Glu放射性低于对照组,差异均有统计学意义(P0.05)。结论铅暴露可明显抑制AS中GLT-1蛋白的表达,并导致AS的Glu转运体功能下降。     

复方罗红霉素凝胶剂的制备与质量控制

目的研制复方罗红霉素凝胶剂。方法以壳聚糖为凝胶材料按药剂学原理制备复方罗红霉素壳聚糖凝胶剂;采用紫外分光光度法测定复方罗红霉素含量;采用容量法测定谷氨酸锌含量。结果该凝胶剂制备工艺简单,质量控制方法可行,质量稳定。结论本品符合中国药典凝胶剂项下有关的各项规定。     

羧基肽酶-H抗体与LADA患者胰岛β细胞功能关系的横断面研究

目的：探讨羧基肽酶-H自身抗体（CPH—Ab）与成人隐匿性自身免疫性糖尿病（LADA）患者胰岛β细胞功能的关系,以进一步明确其对LADA的诊断价值。方法：选择临床初诊2型糖尿病（T2DM）患者545例,采用放射配体法检测血清CPH—Ab和谷氨酸脱羧酶抗体（GAD-Ab）滴度,以筛出的CPH-Ab阳性患者为病例组,以GAD—Ab阳性患者和抗体阴性的T2DM患者为对照组,比较3组研究对象的胰岛β细胞功能（以空腹和餐后2hC肽值表示）,分析CPH-Ab与成人隐匿性自身免疫性糖尿病（LADA）患者胰岛β细胞功能的关系。结果：CPH—Ab阳性患者的空腹C肽介于GAD-Ab阳性与两种抗体（GAD-Ab和CPH—Ab）均阴性的T2DM患者之间（P〈0.05）,以病程分层后三者的C肽值仍具有统计学意义（均P〈0．05）,而以BMI分层无明显差异（均P〉0．05）。经以年龄、起病年龄、病程、性别等为协变量校正后,3组间的空腹C肽和餐后2hC肽值仍存在显著性差异（均P〈0,001）,其中CPH—Ab^＋组仅空腹C肽低于Ab—T2DM组（P〈0,05）,而GAD—Ab^＋组空腹和餐后2hC肽均低于Ab^-T2DM组（P〈0．05和P〈0．01）。胰岛素缺乏患者在CPH-Ab^＋组、GAD-Ab^＋组和Ab—T2DM组的比例分别为27．6％（8／29）,48．1％（8／52）和13．5％（54／400）,三者间差异有统计学意义（P〈0.001）。多元线性逐步回归分析提示,GAD-Ab,BMI和空腹血糖对T2DM患者的空腹C肽和餐后2hC肽均有影响（均P〈0．05）,而CPH-Ab与二者均无统计学相关（均P〉0．05）。结论：CPH抗体对LADA患者胰岛β细胞功能的影响不如GAD-Ab显著,CPH-Ab对LADA患者胰岛功能衰减的作用需前瞻性研究。     

褪黑素对吗啡依赖催促戒断大鼠不同脑区谷氨酸和γ-氨基丁酸含量的影响

目的 观察褪黑素(melatonin,MT)对吗啡催促戒断大鼠不同脑区谷氨酸(glutamate,Glu)和γ-氨基丁酸(gamma-aminobutyric acid,GABA)水平变化的影响.方法 以剂量递增法连续5 d背部皮下注射盐酸吗啡复制慢性吗啡依赖模型.实验分生理盐水对照组(normal saline,NS)、吗啡依赖组(morphine,MOR)、催促戒断组(naloxone,NAL)和褪黑素治疗组(MT组),采用高效液相色谱法(high performance liquid chromatograph,HPLC)测定大鼠脑桥、中脑、海马、间脑和纹状体Glu和GABA含量.结果 与NS组相比,MOR组大鼠脑桥Glu含量明显升高(P＜0.01)而中脑、海马、间脑和纹状体则未见明显变化,脑桥、中脑、间脑和纹状体GABA含量明显升高(P＜0.05,P＜0.01);NAL组脑桥、中脑、海马、间脑和纹状体Glu含量进一步显著升高(P＜0.05,P＜0.01),而GABA含量则迅速下降(P＜0.05,P＜0.01);与NAL组相比,MT抑制吗啡催促戒断大鼠脑内Glu水平的升高(P＜0.05,P＜0.01)和GABA水平的下降(P＜0.05,P＜0.01).结论 MT对吗啡依赖纳洛酮催促戒断大鼠不同脑区的Glu和GABA水平具有调节作用.     

激动mGluR8可缓解母婴分离模型大鼠的内脏高敏感

背景:激动亲代谢型谷氨酸受体8(mGluR8)在中枢神经系统中有抗痛觉过敏的作用,但在胃肠道的研究甚少.内脏高敏感为肠易激综合征(IBS)的病因之一.目的:探讨mGluR8对母婴分离(NMS)模型大鼠内脏高敏感的影响及其可能的机制.方法:24只SD雄性新生大鼠随机分为正常对照(NC)组、NMS组和mGluR8特异性激动...