高糖环境对Mü ller细胞谷氨酸转运体及谷氨酰胺合成酶表达的影响

目的:研究高糖环境对原代培养新生7天SD乳鼠视网膜Mü ller细胞谷氨酸转运合成系统的影响及其可能机制.方法:新生7天SD乳鼠视网膜Mü ller细胞原代培养并模拟高糖环境构建乳鼠视网膜mü ller细胞体外高糖环境模型.处理分为3组:对照组,高糖组,高糖+白藜芦醇干预组.培养时间为24h,通过western blot等检测方法,对照观察各组Mü ller细胞谷氨酸转运体(GLAST)、谷氨酰胺合成酶(GS)的表达情况.结果:模拟高糖环境可以造成新生SD乳鼠视网膜Mü ller细胞谷氨酸转运体(GLAST)表达的降低(0.225 fold VS control,P＜0.05),并导致其表达的谷氨酰胺合成酶(GS)表达水平的显著降低(0.653 fold VS control,P＜0.05);而干预药物白藜芦醇作用后可明显逆转新生SD乳鼠Mü ller细胞谷氨酸转运体(GLAST) (1.133 fold VS H G group,P＜0.05)、谷氨酰胺合成酶(GS) (1.720 fold VS HG group,P＜0.05)等蛋白的表达水平.结论:模拟高糖环境可以影响视网膜Mü ller细胞谷氨酸转运体(GLAST)、谷氨酰胺合成酶的表达,其结局可能导致视神经细胞因谷氨酸堆积而导致的兴奋性毒性,白藜芦醇能提高Mü ller细胞谷氨酸转运体(GLAST)、谷氨酰胺合成酶表达,从而保护视神经细胞.     

缺氧对鼠视网膜Müller细胞GLAST和GS表达及功能的影响

研究了缺氧对鼠视网膜Müller细胞谷氨酸转运体(L-glutamate/L-aspartate transporter,GLAST)和谷氨酰胺合成酶(glutamine synthetase,GS)表达的影响,及对谷氨酸摄取的作用.采用出生3～7天的小鼠视网膜组织进行Müller细胞培养,采用125μmol/L的氯化钴(CoCl2)溶液分别进行缺氧干预6、12、24、48和72 h,不加CoCl2溶液培养的Müller细胞为正常对照.采用RT-PCR法、Western blot法和免疫细胞化学染色法检测GLAST和GS的表达,并检测谷氨酸摄取及细胞凋亡情况.结果显示,缺氧早期GLAST表达较正常对照组增强(P<0.001),CoCl2溶液干预12 h后达到最强(P<0.05),之后逐渐降低.CoCl2溶液干预72 h后GLAST表达与正常对照组相比无明显差异(P>0.05).而缺氧也使GS的表达较正常对照组增加(P<0.001),CoCl2溶液干预48 h后GS表达最强(P<0.001),之后开始下降.缺氧促进Müller细胞对谷氨酸的摄取,CoCl2溶液干预48 h后L-[3,4-3H]-谷氨酸的摄取量最大(P<0.005),之后开始下降.CoCl2溶液干预后,Müller细胞死亡数较正常对照组无明显差异(P>0.05).结果表明,在一定时间范围内缺氧能够增强Müller细胞GLAST及GS的表达,增加谷氨酸的摄取.但持续缺氧最终会引起Müller细胞功能失代偿,从而导致谷氨酸的代谢能力降低.     

视神经损伤后视网膜Müller细胞未折叠蛋白反应相关因子IRE-1与GLAST的表达

目的：研究视神经损伤后视网膜Müller细胞中是否有未折叠蛋白反应（UPR）及其与L一谷氨酸/L一天门冬氨酸转运体（GLAST）的关系。方法：视神经钳夹伤模型建立成功后,运用HE染色观察视网膜神经节细胞数目改变,免疫化学染色,免疫荧光双标记,western-blot观察UPR相关因子需肌醇酶1（IRE-1）与GLAST的表达及相关性。结果：视神经钳夹伤后IRE-1与GLAST在视网膜Muller细胞上共表达,,术后第一天前呈上升趋势,在第一天达到顶峰,后呈下降趋势,第七天下降明显。结论：视神经损伤后,IRE-1与GLAST的趋势变化有一定相关性,提示未折叠蛋白反应可能是调控GLAST变化的原因之一。     

视神经损伤后视网膜Müller 细胞未折叠蛋白反应 相关因子IRE-1 与GLAST 的表达

目的:研究视神经损伤后视网膜Müller细胞中是否有未折叠蛋白反应(UPR)及其与L一谷氨酸/L一天门冬氨酸转运体(GLAST)的关系。方法:视神经钳夹伤模型建立成功后,运用HE染色观察视网膜神经节细胞数目改变,免疫化学染色,免疫荧光双标记,western-blot观察UPR相关因子需肌醇酶1(IRE-1)与GLAST的表达及相关性。结果:视神经钳夹伤后IRE-1与GLAST在视网膜Muller细胞上共表达,,术后第一天前呈上升趋势,在第一天达到顶峰,后呈下降趋势,第七天下降明显。结论:视神经损伤后,IRE-1与GLAST的趋势变化有一定相关性,提示未折叠蛋白反应可能是调控GLAST变化的原因之一。     

牛磺酸对高糖培养下视网膜Mü ller细胞GFAP和TAUT表达的影响

目的：通过检测高糖培养条件下视网膜Mü ller细胞神经纤维酸性蛋白（glial fibrillary acid protein,GFAP）和牛磺酸转运蛋白（taurine transporter,TAUT）的表达变化,观察葡萄糖对Mü ller细胞牛磺酸（taurine）转运功能的影响,探讨牛磺酸对早期糖尿病视网膜病（DR）可能的保护作用.方法：高糖培养大鼠视网膜Mü ller细胞,用免疫细胞荧光化学双染色、Western blotting技术检测不同浓度牛磺酸干预下Mü ller细胞GFAP及TAUT的蛋白表达.结果：高糖可引起Mü ller细胞GFAP表达增强,TAUT表达减弱;牛磺酸可减弱高糖引起的Mü ller细胞GFAP表达增强,TAUT在0.1mmol/L～10 mmo1/L的牛磺酸干预后表达增强.结论：牛磺酸可以抑制高糖导致的Müller细胞功能改变.     

GS、E—cadherin和β-catenin在肝细胞癌中的表达及其临床意义

目的探讨谷氨酰胺合成酶（glutamine synthetaseGS）、E-钙粘蛋白（E—cadherin）和β-连环蛋白（β-catenin）在肝细胞癌中的表达及其与临床病理特征和预后的关系。方法采用免疫组织化学Envision法检测182例肝细胞癌和92例癌旁肝组织中GS、E-cadherin和β-catenin的表达情况,并分析其与临床病理特征和预后的关系。结果GS在肝细胞癌阳性表达率为77．5％,明显高于癌旁肝组织（4．3％）,差异显著（P〈0．05）;肝细胞癌E—cadherin和β-catenin异常表达率分别为59．3％和58．8％,亦高于癌旁肝组织（30．4％和26．1％）,差异显著（P〈0．05）。肝细胞癌中GS的表达与TNM分期、转移和术后复发显著相关（P〈0．05）;E—cadherin和β-catenin异常表达与脉管内瘤栓、TNM分期、转移和术后复发显著相关（P〈0．05）。肝细胞癌中GS表达与E-cadherin、β-catenin异常表达正相关。结论肝细胞癌中GS的高表达,与E-cadherin和β-catenin表达的下调,可能是肝细胞癌侵袭和转移的重要机制之一,联合检测GS、E-cadherin和β-catenin可能有助于判断肝细胞癌的恶性程度、转移潜能及预后分析。     

Wnt信号通路GS蛋白在胃癌中的表达和临床意义

目的：研究wnt信号通路的中GS蛋白（谷氨酰胺合成酶）在胃癌组织中的表达,探索其在胃癌发生、发展中的意义。方法：用免疫组织化学法测定胃癌组织（110例）、肠化生组织（30例）、不典型增生组织（20例）及慢性浅表性胃炎组织（60例）中GS蛋白表达。用快速尿素酶法与病理组织切片染色法检测上述各组织中HP感染的情况,并予统计学分析比较其差异。结果：胃癌组织GS高蛋白表达与组织分型、分化程度、淋巴结转移密切相关（P〈0．05）,与肿瘤大小、部位、TNM分期、Borrmann分型、性别、年龄等无明显相关（P〉0．05）。GS表达与HP感染密切相关。结论：GS蛋白高表达同胃癌生物学行为密切相关,在胃癌的发生、发展中起重要作用。     

牛磺酸对高糖培养下视网膜Mü ller细胞GFAP和TAUT表达的影响

目的:通过检测高糖培养条件下视网膜Müller细胞神经纤维酸性蛋白(glial fibrillary acid protein,GFAP)和牛磺酸转运蛋白(taurine transporter,TAUT)的表达变化,观察葡萄糖对Müller细胞牛磺酸(taurine)转运功能的影响,探讨牛磺酸对早期糖尿病视网膜病(DR)可能的保护作用。方法:高糖培养大鼠视网膜Mǜller细胞,用免疫细胞荧光化学双染色、Western blotting技术检测不同浓度牛磺酸干预下Müller细胞GFAP及TAUT的蛋白表达。结果:高糖可引起Müller细胞GFAP表达增强,TAUT表达减弱;牛磺酸可减弱高糖引起的Müller细胞GFAP表达增强,TAUT在0．1mmol/L～10mmol/L的牛磺酸干预后表达增强。结论:牛磺酸可以抑制高糖导致的Müller细胞功能改变。     

肾小球系膜细胞中硫氧还蛋白1过表达对基质金属蛋白酶9表达的影响

为进一步探讨硫氧还蛋白1（thioredoxin1,Trx1）过表达对高糖环境下肾小球系膜细胞基质金属蛋白酶9（Matrix metalloproteinase9．MMP0）表达的影响．采用RT-PCR和明胶酶谱法检测细胞中MMP-9mRNA和酶活性的变化．用脂质体介导瞬时转染法转染正义Trx1及反义Trx1,观察高糖环境Trx1过表达对MMP9表达的影响．结果表明．HBZY-1高糖组与正常糖组比较,MMP9mRNA在12h,24h,48h时表达增加（P〈0．05）,同时酶活性于12h、24h、48h也明显增高（P〈0．01）．转染正义Trx1组细胞,MMP．9mRNA水平及MMP9酶活性,在高糖组与正常糖组差异无统计学意义（P〉0．05）;但转染反义Trx1组和未转染组细胞的MMP9 mRNA水平及酶活性．高糖组均比正常糖组表达增加,差异有统计学意义（P〈0．01）．提示Trx1过表达可抑制高糖环境诱导的肾小球系膜细胞MMP9高表达．     

TXNIP在高糖诱导的小鼠视网膜Müller细胞自噬中的作用及相关机制

目的:探讨硫氧还蛋白相互作用蛋白(thioredoxin interacting protein,TXNIP)对高糖诱导的小鼠视网膜Müller细胞自噬的影响及其可能机制。方法:采用高糖诱导体外培养的小鼠视网膜Muller细胞,通过RNA干扰降低TXNIP的表达,免疫荧光、Western blot和Real-time PCR检测自噬相关蛋白及丝氨酸/苏氨酸激酶/雷帕霉素靶蛋白(serine/threonine kinase 1/mechanistic target of rapamycin kinase,AKT/m TOR)的表达。结果:高糖诱导的Muller细胞中TXNIP、微管相关蛋白1轻链3α(microtubule associated protein 1 light chain 3 alpha,LC3Ⅱ)、Sequestosome1(p62/SQSTMl)的表达均显著增加(P<0.05);而TXNIP敲降的Muller细胞中自噬相关特征性蛋白(LC3Ⅱ、P62)的表达则显著降低(P<0.05)。结论:TXNIP可能通过AKT/m TOR信号通路来抑制糖尿病性视网膜病变中Müller细胞自噬活性,并引起细胞发生凋亡。     

G1对EA.hy926内皮细胞内质网应激的抑制作用

目的观察GPR30受体激动剂G1对高糖诱导的EA.hy926内皮细胞内质网应激(endoplasmic reticulum stress,ERS)的影响。方法选用EA.hy926内皮细胞为研究对象,分为3组:正常对照组(Con,17.51mmol/L葡萄糖)、高糖组(HG,33.3mmol/L葡萄糖)、高糖+G1组(HG+G1,HG+1umol/L G1),利用流式细胞术检测3组细胞凋亡率,Western blot法检测ERS相关分子Bip、IRE1、PERK及凋亡分子Bax、Bcl-2的表达变化,RT-PCR法检测Bip和CHOP的mRNA表达变化。结果 HG组与Con组比较,细胞凋亡率明显升高(P0.01),Bip、IRE1、PERK及凋亡分子Bax表达上调(P0.01,P0.05或P0.001),Bcl-2的表达下调(P0.01),Bip mRNA、CHOP mRNA表达上调(P0.001及P0.01);HG+G1组与HG组比较,细胞凋亡率明显降低(P0.05),Bip、IRE1、PERK及凋亡分子Bax表达下调(P0.05或P0.01),Bcl-2的表达上调(P0.05),Bip mRNA、CHOP mRNA表达下调(P0.001及P0.01)。结论 GPR30受体激动剂G1可抑制EA.hy926内皮细胞内质网应激。     

Resveratrol Prevents Retinal Dysfunction by Regulating Glutamate Transporters,Glutamine Synthetase Expression and Activity in Diabetic Retina

This study investigated the effects of resveratrol (RSV) on retinal functions, glutamate transporters (GLAST) and glutamine synthetase (GS) expression in diabetic rats retina, and on glutamate uptake, GS activity, GLAST and GS expression in high glucose-cultured Müller cells. The electroretinogram was used to evaluate retinal functions. Müller cells cultures were prepared from 5- to 7-day-old Sprague–Dawley rats. The expression of GLAST and GS was examined by qRT-PCR, ELISA and western-blotting. Glutamate uptake was measured as ³H-glutamate contents of the lysates. GS activity was assessed by a spectrophotometric assay. 1- to 7-month RSV administrations (5 and 10 mg/kg/day) significantly alleviated hyperglycemia and weight loss in diabetic rats. RSV administrations also significantly attenuated diabetes-induced decreases in amplitude of a-wave in rod response, decreases in amplitude of a-, and b-wave in cone and rod response and decreases in amplitude of OP2 in oscillatory potentials. 1- to 7-month RSV treatments also significantly inhibited diabetes-induced delay in OP2 implicit times in scotopic 3.0 OPS test. The down-regulated mRNA and protein expression of GLAST and GS in diabetic rats retina was prevented by RSV administrations. In high glucose-treated cultures, Müller cells’ glutamate uptake, GS activity, GLAST and GS expression were decreased significantly compared with normal control cultures. RSV (10, 20, and 30 mmol/l) significantly inhibited the HG-induced decreases in glutamate uptake, GS activity, GLAST and GS expression (at least P < 0.05). These beneficial results suggest that RSV may be considered as a therapeutic option to prevent from diabetic retinopathy.     

Immunohistochemical Localization of GFAP and Glutamate Regulatory Proteins in Chick Retina and Their Levels of Expressions in Altered Photoperiods

Moderate to intense light is reported to damage the chick retina, which is cone dominated. Light damage alters neurotransmitter pools, such as those of glutamate. Glutamate level in the retina is regulated by glutamate–aspartate transporter (GLAST) and glutamine synthetase (GS). We examined immunolocalization patterns and the expression levels of both markers and of glial fibrillary acidic protein (GFAP, a marker of neuronal stress) in chick retina exposed to 2000 lux under 12-h light:12-h dark (12L:12D; normal photoperiod), 18L:6D (prolonged photoperiod), and 24L:0D (constant light) at post-hatch day 30. Retinal damage (increased death of photoreceptors and inner retinal neurons and Müller cell hypertrophy) and GFAP expression in Müller cells were maximal in 24L:0D condition compared to that seen in 12L:12D and 18L:6D conditions. GS was present in Müller cells and GLAST expressed in Müller cell processes and photoreceptor inner segments. GLAST expression was decreased in 24L:0D condition, and the expression levels between 12L:12D and 18L:6D, though increased marginally, were statistically insignificant. Similar was the case with GS expression that significantly decreased in 24L:0D condition. Our previous study with chicks exposed to 2000 lux reported increased retinal glutamate level in 24L:0D condition. The present results indicate that constant light induces decreased expressions of GLAST and GS, a condition that might aggravate glutamate-mediated neurotoxicity and delay neuroprotection in a cone-dominated retina.     

BDNF regulates GLAST and glutamine synthetase in mouse retinal Müller cells

This study investigated whether brain-derived neurotrophic factor (BDNF) regulates the L-glutamate/L-aspartate transporter (GLAST) and glutamine synthetase (GS) in mouse retinal Müller cells (RMCs) under normal and hypoxic conditions. Mouse RMCs were treated with recombinant human BDNF (50, 75, 100, 125, or 150 ng/ml) for 24 h or underwent hypoxia induced by CoCl(2) (125 μM; 6, 12, 24, 48, or 72 h). An additional group underwent combined treatment with BDNF (100 ng/ml; 24, 48, 72, or 96 h) and CoCl(2) (125 μM/ml; 72 h). GLAST and GS mRNA and protein expression, L-[3,4-3H]-glutamic acid uptake, and apoptosis were assessed. BDNF dose-dependently up-regulated GLAST and GS mRNA and protein and increased glutamate uptake. Similarly, in early-stage CoCl(2)-induced hypoxia, GLAST and GS were up-regulated and glutamate uptake increased, but these decreased over time. BDNF also up-regulated GLAST and GS and increased glutamate uptake when RMCs under CoCl(2) induced hypoxic condition. However, BDNF treatment 24 h before CoCl(2) had no effect on GLAST or GS expression. CoCl(2) alone or combined with BDNF did not induce apoptosis. Hypoxia rapidly increased GLAST and GS expressions. This effect was transient, perhaps due to compensatory mechanisms that reduce GLAST and GS by 72 h. BDNF can up-regulate GLAST and GS and increase glutamate uptake during hypoxia, and these functions may underlie its neuroprotective effects.     

波动性高糖对肾小管上皮细胞Wnt／β-catenin信号途径的影响

肾脏纤维化分为肾小球硬化和肾小管间质纤维化（tubular interstitial fibrosis,TIF）,而TIF过程与肾损伤具有密切的关系。TIF是由于细胞外基质的过度沉积造成的,肌成纤维细胞是TIF发生发展过程中产生细胞外基质的主要细胞,该过程被成纤维细胞激活,涉及上皮细胞向肌成纤维细胞的转分化^[1-2]。Wnt／β-catenin信号途径涉及细胞增殖、肿瘤发生与转移的调控。β-catenin是Wnt信号途径的关键分子,在细胞的生长与分化过程中起着重要的作用,     

白藜芦醇对高糖条件下大鼠晶状体上皮细胞线粒体活性氧产生及内质网的影响

目的：探讨白藜芦醇（resveratrol,Res）对高糖条件下大鼠晶状体上皮细胞（LECs）凋亡、线粒体活性氧产生以及内质网表达的影响。方法：用含30 mmol·L-1葡萄糖浓度的培养基体外培养LECs,随后加入25 mg·L-1Res共培养48 h。流式细胞术检测LECs细胞凋亡情况和线粒体膜电位的变化。激光共聚焦显微镜观察线粒体活性氧变化情况,并用免疫组化法检测内质网表达。结果：在高糖培养条件下,与对照组相比,LECs死亡率明显增高,线粒体膜电位降低,活性氧增多。内质网阳性率明显下降。经Rev干预后,细胞凋亡率显著降低,线粒体膜电位和内质网阳性率均升高,活性氧产生明显减少（P〈0.05）。结论：白藜芦醇能在一定程度上减轻糖尿病性白内障大鼠晶状体凋亡的发生并维持正常细胞器功能,从而延缓白内障的发生和发展。     

脑内谷氨酸、乳酸以及葡萄糖对中重型脑外伤患者病情的评价意义

目的：应用微透析技术对于中重型脑外伤患者进行持续脑内谷氨酸、乳酸以及葡萄糖,分析结果以评价以上因素与患者病情的关系。方法：选择我院2006年3月-2009年11月颅脑外科和ICU收治的急性颅脑损伤患者32例,根据GCS分为重度昏迷组和中度昏迷组,均行急诊手术治疗,并在手术直视下置入微透析探针,置入后第4天拔除,定时收集透析液约10μl,于术前以及术后第1、2、3、4天收取标本并立即送检,分别检测患者标本中的谷氨酸、乳酸和葡萄糖含量,并结合患者预后进行分析。结果：中度昏迷组乳酸与谷氨酸值在手术后呈进行性下降,与术前比较,术后第2、3、4天差异有统计学意义（P〈0．05）,乳酸值的变化与谷氨酸变化趋势相近,与术前比较,在术后第3、4天差异有统计学意义（P〈0．05）,葡萄糖值与术前比较,术后第2、3、4天差异有统计学意义（P〈0．05）;重度昏迷组谷氨酸、乳酸和葡萄糖与术前比较,三者均在第4天出现有统计学意义的变化。重度昏迷组谷氨酸测量值在各个观察点均高于中度昏迷组测量值（P〈0．05）,乳酸值亦明显高于中度昏迷组测量值（P〈O．05）,葡萄糖测量值两组术前测量值差异无统计学意义（P〉0．05）,自术后第1天始,中度昏迷组各个时间点测量值明显高于重度昏迷组。结论：结合患者的GCS评分,应用微透析技术实时监测患者脑内谷氨酸、乳酸以及葡萄糖的含量变化,能很好的把握患者的病情,有效指导临床治疗。     

EPO修饰增强Muller细胞对RCS大鼠视网膜变性的干预效果

目的：研究人源促红细胞生成素（hEPO）修饰的Müller（hEPO-Müller）细胞对视网膜退行性病变大鼠的干预作用。方法通过质粒转染法构建hEPO和GFP的Müller细胞稳转株（hEPO-Müller和GFP-Müller）;以体外共培养和体内细胞移植为研究体系,利用RT-PCR和冰冻切片及免疫荧光染色的方法检测hEPO-Müller对RCS大鼠视网膜退行性病变的干预作用。内核层与外核层厚度比较采用t检验。结果本实验成功构建了hEPO-Müller和GFP-Müller细胞系。将RCS大鼠的视网膜组织剥离并在体外不同条件下培养两周后测定视网膜各核层厚度发现,与对照细胞裂解液共培养组的内核层（15.94±1.77）μm和外核层（24.81±3.03）μm的厚度相比较,两核层的厚度分别在hEPO组为（23.03±3.29）μm,（33.92±7.59）μm（P〈0.05）;Müller 组为（24.81±2.02）μm,（32.15±3.03）μm（P〈0.05）;hEPO-Müller组为（32.40±8.35）μm,（40.25±3.29）μm（n=3, P〈0.01）;以hEPO-Müller组厚度增加最为显著（P〈0.05）。提示EPO和Müller细胞对视网膜变性都有干预作用且两者可以叠加。将hEPO-Müller和GFP-Müller分别移植到RCS大鼠的视网膜下腔,四周后取视网膜进行冰冻切片检测,染色结果显示,细胞移植后有更多的外核层细胞存活,且同样也是hEPO-Müller组的外核层细胞更多。此外,Müller移植并不会促进视网膜的胶质化。结论移植Müller细胞可以减缓RCS大鼠视网膜变性,而经hEPO修饰的Müller细胞对视网膜变性有更好的干预作用。因此,Müller细胞可以作为一种供体细胞兼携带hEPO等营养因子的载体用于视网膜变性的治疗。     

Differential perturbation of neuronal and glial glutamate transport systems in retinal ischaemia

Glutamate is the major excitatory neurotransmitter in the retina and is removed from the extracellular space by an energy-dependent process involving neuronal and glial cell transporters. The radial glial Müller cells express the glutamate transporter, GLAST, and preferentially accumulate glutamate. However, during an ischaemic episode, extracellular glutamate concentrations may rise to excitotoxic levels. Is this catastrophic rise in extracellular glutamate due to a failure of GLAST? Using immunocytochemistry, we monitored the transport of the glutamate transporter substrate, D-aspartate, in the retina under normal and ischaemic conditions. Two models of compromised retinal perfusion were compared: (1) Anaesthetised rats had their carotid arteries occluded for 7 days to produce a chronic reduction in retinal blood flow. Retinal function was assessed by electroretinography. D-aspartate was injected into the eye for 45 min. Following euthanasia, the retina was processed for D-aspartate, GLAST and glutamate immunocytochemistry. Although reduced retinal perfusion suppresses the electroretinogram b-wave, neither retinal histology, GLAST expression, nor the ability of Müller cells to uptake D-aspartate is affected. As this insult does not appear to cause excitotoxic neuronal damage, these data suggest that GLAST function and glutamate clearance are maintained during periods of reduced retinal perfusion. (2) Occlusion of the central retinal artery for 60 min abolishes retinal perfusion, inducing histological damage and electroretinogram suppression. Although GLAST expression appears to be normal, its ability to transport D-aspartate into Müller cells is greatly reduced. Interestingly, D-aspartate is transported into neuronal cells, i.e. photoreceptors, bipolar and ganglion cells. This suggests that while GLAST is vitally important for the clearance of excess extracellular glutamate, its capability to sustain inward transport is particularly susceptible to an acute ischaemic attack. Manipulation of GLAST function could alleviate the degeneration and blindness that result from ischaemic retinal disease.