生后小鼠不同年龄阶段视网膜片层化及胶质细胞发育特点

目的:观察小鼠视网膜片层化过程中胶质细胞增殖及与双极细胞分化的关系。方法:各个年龄小鼠共计123只。应用免疫荧光和HE染色法对各个年龄的小鼠视网膜形态结构及胶质细胞的增殖、分化进行观察。结果:星形胶质细胞按照离心型的模式发育,P0时仅在视乳头和邻近周围区域出现幼稚的星形胶质细胞,尔后细胞突起相互缠绕形成的网状联系中出现中空"管样"结构,细胞形态呈现典型的星状外形,类似血管网的脉络。P6时小鼠视网膜Müller细胞零星的表达GS,双极细胞也开始表达少量的PKC-α,尔后Müller细胞GS阳性表达逐渐增加,而PKC-α阳性细胞伸向节细胞层的轴突更加密集,树突和胞体的数量也增多,P14时双极细胞的发育过程基本完成。同时,小鼠视网膜GS和PKC-α双标记,发现Müller细胞内、外突上发出许多细小的侧突与双极细胞的胞体相接触,提示Müller细胞在双极细胞的分化、迁移过程中伴着很重要的角色。结论:在小鼠视网膜片层化过程中,胶质细胞起着关键性作用,Müller细胞在双极细胞的分化、迁移过程中起重要作用。     

新生小鼠吸入高氧视网膜的血管发育与胶质纤维酸性蛋白表达的变化

目的:研究新生小鼠吸入高氧视网膜病(ROP)过程中胶质纤维酸性蛋白(GFAP)表达的变化规律,探讨Müller细胞与血管发育的关系。方法:实验用生后7 d(P7)C57BL/6J小鼠。ROP模型组在75%氧环境中饲养。在P9、P12、P14、P17和P21等不同时间取眼球,分别用ADP酶组织化学染色方法显示视网膜血管发育及免疫组织化学方法标记视网膜GFAP的表达。结果:小鼠视网膜血管生后开始发育,P21基本成熟;吸高氧后从P14开始出现新生血管,在P17~P21达到高峰。模型鼠视网膜Müller细胞从P14起内侧突起开始表达GFAP,到P21已遍布细胞全层。结论:高氧可导致视网膜发育晚期大量血管新生,且与GFAP表达的变化规律相一致,提示Müller细胞与视网膜血管发育关系密切。     

N-甲基-N-亚硝脲诱导的大鼠视网膜感光细胞损伤模型中Müller细胞增殖和细胞因子分泌的变化

目的:建立N-甲基-N-亚硝脲(N-methyl-N nitrosourea,MNU)损伤视网膜的模型,研究视网膜神经元凋亡对Müller细胞生物学特性的影响及神经营养因子的表达变化。方法:腹腔注射MNU建立视网膜损伤模型,免疫荧光染色方法研究感光细胞缺失对Müller细胞的生物学特性的影响,并检测主要神经营养因子表达的变化。结果:TUNEL法显示,腹腔注射MNU后2 d,视网膜外核层细胞凋亡现象明显。核增殖抗原(PCNA)及细胞周期素CyclinD_1的表达明显增高。与此同时,Müller细胞也开始表达神经干细胞抗原巢蛋白(nestin);RT-PCR显示胰岛素样生长因子(IGF),碱性成纤维细胞生长因子(bFGF)和肝细胞生长因子(HGF)mRNA的表达均升高。结论:在视网膜受到损伤时,Müller细胞增殖、去分化呈现出干细胞的特性。而视网膜中IGF、bFGF和HGF等细胞因子的表达明显增高,提示视网膜损伤后可能通过大量分泌细胞生长因子,促进Müller细胞的增殖。     

过表达Cdh1蛋白对高糖诱导的视网膜Müller细胞株GFAP表达的影响

目的 探讨过表达Cdh1蛋白对高糖诱导的视网膜Müller细胞株GFAP表达的影响.方法 培养的Müller细胞分为4组:对照组(Control)、高糖组(HG group,30 mmol/L葡萄糖)、Cdh1过表达组(Cdh1,30 mmol/L葡萄糖+过表达Cdh1蛋白的慢病毒载体)、病毒阴性对照组(NC-Cdh1,30 mmol/L葡萄糖+慢病毒载体稀释液),显微镜下观察Müller细胞一般生长状况,免疫荧光检测GFAP在Müller细胞的表达情况,Western blot检测Müller细胞GFAP及Cdh1蛋白的相对表达.结果 HG组和NC-Cdh1组GFAP表达水平明显高于Control组,Cdh1明显低于Control组(P＜0.05);Cdh1组GFAP表达水平明显低于HG组,Cdh1高于HG组(P＜0.05),而HG组和NC-Cdh1组之间无统计学意义(P＞0.05).结论 过表达Cdh1蛋白下调高糖诱导的视网膜Müller细胞GFAP表达,对高糖诱导的Müller细胞损伤起到保护作用.     

Müller细胞在增殖性糖尿病视网膜病变中的最新研究进展

Müller细胞是脊椎动物视网膜中的主要胶质细胞, 其纵向跨越整个视网膜, 几乎与视网膜中的每一种细胞类型都有接触。因其独特的定位, 可以参与维持视网膜内稳态所需的各种功能。增殖性糖尿病视网膜病变(proliferative diabetic retinopathy, PDR)是糖尿病的眼部并发症, 在炎症的作用下内皮细胞、神经元和神经胶质细胞之间相互作用造成眼底微血管病变。在PDR中, Müller细胞经历反应性胶质增生, 一方面起到保护视网膜的作用, 另一方面, 由于炎性细胞因子/趋化因子的水平升高, 可导致瘢痕和视网膜新生血管形成, 损害玻璃体。由此可见, Müller细胞胶质化对于视网膜有着双重作用。另外, Müller细胞表达低密度脂蛋白受体相关蛋白-1(low density lipoprotein receptor associated protein 1, LRP1), LRP1对新生血管和炎症有着密切联系。对Müller细胞、PDR玻璃体和LRP1展开研究可能为"趋利避害"提供新思路。     

糖基化终末产物对培养的兔视网膜Müller细胞bFGF表达的影响

目的:观察在不同剂量糖基化终产物(AGEs)条件下,对体外培养的视网膜Müller细胞碱性成纤维生长因子(b FGF)表达的影响及其机制。方法:采用免疫细胞化学及透射电镜方法鉴定体外培养的兔视网膜Müller细胞;应用免疫细胞化学方法半定量观察640μl/2 000μl AGEs条件下视网膜Müller细胞b FGF表达的变化;利用RT-PCR技术观察AGEs、PKC抑制剂Calphostin C对视网膜Müller细胞b FGF mRNA表达的影响。结果:640μl/2 000μl AGEs可刺激视网膜Müller细胞表达b FGF,Calphostin C可明显抑制AGEs引起的b FGF mRNA表达的增加,在浓度为50 nmol/L时其抑制作用最强。结论:AGEs刺激Müller细胞b FGF的表达,发挥促血管生成的作用,b FGF mRNA的表达可能是通过激活PKC途径实现的。     

GMFB在高糖处理的Müller细胞中的表达及其对Müller细胞的影响

目的:利用高糖处理Müller细胞,研究高糖条件下胶质细胞成熟因子B(glia maturation factor-β,GMFB)的表达情况和GMFB对Müller细胞的影响,揭示GMFB细胞在糖尿病视网膜病变中可能的作用机制,为糖尿病视网膜病变的治疗提供新的策略。方法:(1)用25mmol/L葡萄糖处理Müller细胞0,1,2,4和6 h,采用Western Blot检测GMFB的表达;(2)用自噬双标腺病毒(mRFP-GFP-LC3)感染Müller细胞后,1μg/ml重组蛋白GMFB处理Müller细胞0,2,4,8,12 h,采用Western Blot和免疫荧光检测自噬情况;(3)1μg/ml GMFB处理Müller细胞24 h为实验组,以未处理组作为对照组,进行RNAseq,检测其基因差异表达谱,选取其中表达差异大于1.5倍且P0.05的基因作为差异表达的基因,对其进行基因本体论(gene ontology,GO)分析及京都基因和基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)富集分析。结果:(1)经高糖处理的Müller细胞早期出现GMFB表达上调,以2 h处理组的GMFB上调最为显著,提示高糖刺激早期能引起Müller细胞的GMFB表达升高;(2)重组蛋白GMFB处理Müller细胞后,Western Blot在第4 h检测到自噬被诱导,但很短暂。我们在24 h用免疫荧光检测,没有发现红绿荧光强度变化,提示双标自噬系统检测未检测到自噬发生,可能与不同检测方法的敏感性不同有关。(3)对GMFB处理24 h的Müller细胞抽提总RNA,进行RNAseq检测,显示在被检测的14411个基因中,实验组和正常组间有显著差异表达的基因有152个。与对照组相比,实验组基因表达显著上调的有103个,下调的有44个。通过GO分析表明,GMFB与细胞代谢、细胞催化等生物过程相关。KEGG分析进一步发现GMFB与细胞黏附分子、轴突导向和胞质DNA感受通路等多条信号通路密切相关。同时,炎症基因IL-33表达降低,提示GMFB有神经保护的作用。结论:GMFB在高糖诱导的Müller细胞中表达明显上调,说明GMFB可能影响细胞间连接,参与炎症反应信号通路等。该工作为理解GMFB在糖尿病视网膜病变中的作用机制提供了有益的线索。GMFB在糖尿病视网膜病变的作用机制需要进一步验证。     

胰岛素对体外培养的视网膜Müller细胞VEGF变化影响的研究

目的:观察在不同浓度胰岛素条件下,体外培养的兔视网膜Müller细胞的血管内皮生长因子(vascular endothelial growth factor, VEGF)表达的变化.方法: 采用免疫细胞化学法和ELISA方法,定性定量测定不同浓度胰岛素条件下体外培养的兔视网膜Müller细胞VEGF的表达. 结果:胰岛素能明显增强VEGF的表达. 结论: 高浓度胰岛素可增强Müller细胞VEGF的表达,这种VEGF表达水平的升高可能是胰岛素促进糖尿病视网膜病变的因素之一.     

Müller细胞反应性胶质化在急性高眼压致大鼠视网膜损伤中作用

 目的 观察Müller细胞反应性胶质化在急性高眼压(AOH)大鼠视网膜中变化及其抑制对视网膜损伤的影响。方法 建立大鼠AOH青光眼模型,分为正常对照(Ctrl)、AOH和AOH+玻璃体内注射胶质毒素α-氨基己二酸(AAA)后再灌注1、3和5d组,以及单纯AAA和AOH+PBS对照组。TUNEL染色检测细胞凋亡,GFAP免疫荧光染色反应Müller细胞反应性胶质化程度,Thy-1染色标记视网膜神经节细胞(RGCs)。结果 AOH可致大鼠视网膜内丛状层和内核层明显变薄、神经节细胞层内细胞排列紊乱和数量减少,并诱发Müller细胞反应性胶质化(GFAP表达增加)。同时,AAA抑制Müller细胞反应性胶质化可明显缓解AOH所致RGCs丢失和凋亡发生。结论 Müller细胞反应性胶质化参与AOH所致视网膜损伤,抑制其反应性胶质化可能是改善高眼压性青光眼视网膜病变的一种有效治疗方法。     

大鼠Mlüler细胞的体外培养及免疫组织化学鉴定

Müller细胞是视网膜中一种非常重要的胶质细胞。成熟的Müller细胞发出很多分支包围、分隔神经元的胞体和突起[1]。研究表明Müller细胞在外伤或光损伤后可表达多种生长因子,这些生长因子除对神经元具有保护作用外[2],对细胞外环境也具有调控作用[3]。因此,Müller细胞在视网膜中的作用正日益受到人们的重视。而Müller细胞的培养方法主要有组织块贴壁培养法和酶解法。本实验应用酶解法成功分离了大鼠视网膜的Müller细胞,并进行体外培养、免疫组化鉴定,为进一步研究胶质细胞在中枢神经系统的作用提供实验基础。1材料和方法1.1实验动物…     

Intermediate filament complement of the normal and gliotic canine retina.

Intermediate filament expression of various cell types in the adult canine normal and gliotic retina was determined by an immunoperoxidase method of using monoclonal antibodies on aldehyde-fixed tissues. In the normal retina, vimentin was present in astrocytes in the nerve fibre layer, horizontal cell processes, and Müller cell fibres from the internal limiting membrane to the outer nuclear layer. Neurofilamentous axons were noted in the nerve fibre, inner plexiform layer, and outer plexiform layer, although the degree of staining intensity varied among the three molecular weight neurofilament antisera used. Glial fibrillary acidic protein (GFAP) staining was confined to the nerve fibre and ganglion cell layer; this was interpreted as representing fibrous astrocytes. Astrocyte density varied according to retinal topography with an increased number around retinal blood vessels and in the peripapillary retina. Quantitative, but not qualitative differences in staining for vimentin and the neurofilaments were noted in degenerative, gliotic retinas. In common with several other mammalian species previously studied, the canine Müller cells accumulate or express GFAP under pathological conditions involving a gliotic response.     

Neuronal and glial cell types revealed by NADPH-diaphorase histochemistry in the retina of a teleost fish, the grass goby ( Zosterisessor ophiocephalus , Perciformes, Gobiidae)

The grass goby is a mud-burrowing fish with a rich retinal vasculature appropriate to its hypoxic habitat. NADPH-diaphorase histochemistry was performed on retinal sections and wholemounts to reveal cells that contain nitric oxide synthase and so may be presumed to synthesise nitric oxide, a gaseous intercellular messenger with many roles including vasodilation. Structures that were consistently stained by this method included cone ellipsoids, horizontal cells, Müller cells and their processes, large displaced ganglion cells in the inner nuclear layer (identified by their axons), large interstitial ganglion cells in the inner plexiform layer, and capillary endothelial cells. In wholemounts, horizontal cells were seen to form a regular pattern, contacting each other at their dendritic terminals. Some cells in the ganglion cell layer were weakly stained, but stained bipolar and amacrine cells were not seen. The diaphorase-positive large ganglion cells all formed large, sparsely branched dendritic trees, arborizing near the scleral border of the inner plexiform layer. The displaced and interstitial cells seemed to belong to distinct morphological types, the interstitial cells having smaller somata and trees. Analysis of their spatial distributions in one representative retina confirmed this: the displaced cells formed a highly regular mosaic with a mean spacing (nearest-neighbour distance) of 303 μm, whereas the interstitial cells formed a separate mosaic, almost as regular but with a smaller mean spacing of 193 μm, rising to 217 μm in a sample that excluded the area retinae temporalis. Spatial correlogram analysis showed that these two mosaics were spatially independent. Nitric oxide probably has many roles in the retina. The presence of its synthetic enzyme in Müller cells, which communicate with retinal blood vessels, is consistent with a role in the control of retinal blood flow. Its function in large, mosaic-forming retinal ganglion cells is unknown. Accepted: 29 April 1999     

Highly sialylated N-CAM is expressed in adult mouse optic nerve and retina

Summary The localization of the neural cell adhesion molecule (N-CAM) and its highly sialylated form, which is prevalent in young tissues and has therefore been called embryonic neural cell adhesion molecule, was studied in the developing and adult mouse optic nerve and retina immunohistologically and immunochemically. At embryonic and early postnatal ages, neuroblasts and young postmitotic neurons, Müller cells and astrocytes in the retina, and retinal ganglion cell axons and all glial cells in the optic nerve express highly sialylated neural cell adhesion molecule. Beginning with the third postnatal week, highly sialylated neural cell adhesion molecule disappears from retinal ganglion cell axons in the optic nerve and from neuronal cell bodies and processes in the retina. In addition, it is not detectable on oligodendrocytes in 3-week-old animals. However, highly sialylated neural cell adhesion molecule continues to be expressed in the adult optic nerve and retina by astrocytes and Müller cells. On these cells it is only absent from cell membranes contacting basal lamina. Weakly sialylated neural cell adhesion molecule, in contrast, is expressed by all cell types of retina and optic nerve during development and in the adult. The loss of highly sialylated neural cell adhesion molecule from neurons and oligodendrocytes must therefore be considered as a cell type-specific conversion of the so-called embryonic to the adult form of neural cell adhesion molecule and does not simply reflect the disappearance of neural cell adhesion molecule from these cells. Weakly sialylated neural cell adhesion molecule, however, is absent from outer segments of photoreceptor cells and, as is the case for the highly sialylated form, from glial cell surfaces contacting basal lamina. Thus, the expression of highly sialylated neural cell adhesion molecule by pre- and postmitotic neurons and by oligodendrocytes is restricted mainly to the period of histogenetic events in retina and optic nerve, i.e. cell division, cell migration, dendritic and axonal growth and synaptogenesis. In addition to the observation that this form of neural cell adhesion molecule is less adhesive than the weakly sialylated, adult form, it is likely that highly sialylated neural cell adhesion molecule plays an important role during dynamic morphogenetic events. Furthermore, the expression of highly sialylated neural cell adhesion molecule by astrocytes and Müller cells in adult optic nerves and retinae suggests some histogenetically plastic functions for these cells in the adult mouse visual system.     

Neuronal and glial cell types revealed by NADPH-diaphorase histochemistry in the retina of a teleost fish, the grass goby (Zosterisessor ophiocephalus, Perciformes, Gobiidae)

The grass goby is a mud-burrowing fish with a rich retinal vasculature appropriate to its hypoxic habitat. NADPH-diaphorase histochemistry was performed on retinal sections and wholemounts to reveal cells that contain nitric oxide synthase and so may be presumed to synthesise nitric oxide, a gaseous intercellular messenger with many roles including vasodilation. Structures that were consistently stained by this method included cone ellipsoids, horizontal cells, Müller cells and their processes, large displaced ganglion cells in the inner nuclear layer (identified by their axons), large interstitial ganglion cells in the inner plexiform layer, and capillary endothelial cells. In wholemounts, horizontal cells were seen to form a regular pattern, contacting each other at their dendritic terminals. Some cells in the ganglion cell layer were weakly stained, but stained bipolar and amacrine cells were not seen. The diaphorase-positive large ganglion cells all formed large, sparsely branched dendritic trees, arborizing near the scleral border of the inner plexiform layer. The displaced and interstitial cells seemed to belong to distinct morphological types, the interstitial cells having smaller somata and trees. Analysis of their spatial distributions in one representative retina confirmed this: the displaced cells formed a highly regular mosaic with a mean spacing (nearest-neighbour distance) of 303 µm, whereas the interstitial cells formed a separate mosaic, almost as regular but with a smaller mean spacing of 193 µm, rising to 217 µm in a sample that excluded the area retinae temporalis. Spatial correlogram analysis showed that these two mosaics were spatially independent. Nitric oxide probably has many roles in the retina. The presence of its synthetic enzyme in Müller cells, which communicate with retinal blood vessels, is consistent with a role in the control of retinal blood flow. Its function in large, mosaic-forming retinal ganglion cells is unknown.     

Expression of aquaporin-1 immunoreactivity by photoreceptor cells in the mouse retina

Aquaporin water channels play a crucial role in the maintenance of ionic and osmotic homeostasis in the neural tissue. In the sensory retina, aquaporin-4 is expressed by Müller glial cells, predominantly in the inner retina, while aquaporin-1 is expressed mainly in the outer retina. However, it is unknown whether aquaporin-1 expression occurs in Müller cells or photoreceptor cells. By using immunohistochemical staining of retinal slices from rds mice, we show that the immunoreactivity for aquaporin-1 disappears along with the photoreceptor cell degeneration. In suspensions of dissociated retinal cells from control mice, photoreceptor cells expressed aquaporin-1 immunoreactivity while Müller cells were largely devoid of staining. The data suggest that photoreceptor cells, but not Müller cells, express aquaporin-1 in the murine retina.     

Neuronal expression of P2X3 purinoceptors in the rat retina

P2X3 purinoceptors are involved in fast, excitatory neurotransmission in the nervous system, and are expressed predominantly within sensory neurons. In this study, we examined the cellular and synaptic localization of the P2X3 receptor subunit in the retina of the rat using immunofluorescence immunohistochemistry and pre-embedding immunoelectron microscopy. In addition, we investigated the activity of ecto-ATPases in the inner retina using an enzyme cytochemical method. The P2X3 receptor subunit was expressed in the soma of a subset of GABA immunoreactive amacrine cells, some of which also expressed protein kinase C-alpha. In addition, punctate immunoreactivity was observed within both the inner and outer plexiform layers of the retina. Double labeling studies showed that P2X3 receptor puncta were associated with both rod and cone bipolar cell axon terminals in the inner plexiform layer. Ultrastructural studies indicated that P2X3 receptor subunits were expressed on putative A17 amacrine cells at sites of reciprocal synaptic input to the rod bipolar cell axon terminal. Moreover, we observed P2X3 immunolabeling on amacrine cell processes that were associated with cone bipolar cell axon terminals and other conventional synapses. In the outer retina, P2X3 immunoreactivity was observed on specialized junctions made by putative interplexiform cells. Ecto-ATPase activity was localized to the inner plexiform layer on the extracellular side of all plasma membranes, but was not apparent in the ganglion cell layer or the inner nuclear layer, suggesting that ATP dephosphorylation occurs exclusively in synaptic regions of the inner retina. These data provide further evidence that purines participate in retinal transmission, particularly within the rod pathway.     

Synapsin I expression in the rat retina during postnatal development

Summary The expression of the synapsin I gene was studied during postnatal development of the rat retina at the mRNA and protein levels. In situ hybridization histochemistry showed that synapsin I mRNA was expressed already in nerve cells in the ganglion cell layer of the neonatal retina, while it appeared in neurons of the inner nuclear layer from postnatal day 4 onward. Maximal expression of synapsin I mRNA was observed at P12 in ganglion cells and in neurons of the inner nuclear layer followed by moderate expression in the adult. At the protein level a shift of synapsin I appearance was observed from cytoplasmic to terminal localization during retinal development by immunohistochemistry. In early stages (P4 and P8), synapsin I was seen in neurons of the ganglion cell layer and in neurons of the developing inner nuclear layer as well as in the developing inner plexiform layer. In the developing outer plexiform layer synapsin I was localized only in horizontal cells and in their processes. Its early appearance at P4 indicated the early maturation of this cell type. A shift and strong increase of labelling to the plexiform layers at P12 indicated the localization of synapsin I in synaptic terminals. The inner plexiform layer exhibited a characteristic stratified pattern. Photoreceptor cells never exhibited synapsin I mRNA or synapsin I protein throughout development.Abbreviations GCL ganglion cell layer - INB inner neuroblast layer - INL inner nuclear layer - IPL inner plexiform layer - ONB outer neuroblast layer - ONL outer nuclear layer - OPL outer plexiform layer     

Lamina formation in the Mongolian gerbil retina (Meriones unguiculatus)

Retinae of nocturnal rodents, such as mice and rats, are almost exclusively rod-dominated. The gerbil, in contrast, shows active periods during day and night and uses both rod- and cone-based vision. However, its retina has not been studied in detail, except for one developmental study analysing its prenatal period (Wikler et al. 1989). Here, the formation of the laminar structure of the gerbil retina was studied from birth until late adult stages. At birth, the retina consisted of a wide neuroblastic layer, with 30% of cells still dividing, a rate decreasing to nearly zero by P6. Shortly after birth, segregation of a ganglion cell layer began. All retinal layers reached their final size around P20, as determined from DAPI-stained cryosections. Müller glial cells developed their typical structure from P1 onwards, e.g. announcing an outer plexiform layer (OPL) at P5, as analysed by the Ret-G7 and glutamine synthetase antibodies. The analyses of the inner retina were performed by antibodies to calretinin (CR) and calbindin (CB). CR is expressed in ganglion cells followed by amacrine cells from P1 onwards; their processes formed four subbands in the inner plexiform layer (IPL) and appeared sequentially after P5 until P20. CB stained a subtype of horizontal cells with their processes into the OPL from P14 onwards. The rod-specific antibody rho4D2 announced photoreceptors at P4, showing signs of outer segments from P10 onwards. The study shows that the formation of all retinal layers in the gerbil occurs postnatally. This and the fact that the gerbil retina is not exclusively rod-dominated could render the gerbil a valuable model for in vitro studies of retinogenesis in rodents.     

Bioluminescent imaging of Ca2+ activity reveals spatiotemporal dynamics in glial networks of dark-adapted mouse retina

Glial Ca²⁺ excitability plays a key role in reciprocal neuron–glia communication. In the retina, neuron–glia signalling is expected to be maximal in the dark, but the glial Ca²⁺ signal characteristics under such conditions have not been evaluated. To address this question, we used bioluminescence imaging to monitor spontaneous Ca²⁺ changes under dark conditions selectively in Müller cells, the principal retinal glial cells. By combining this imaging approach with network analysis, we demonstrate that activity in Müller cells is organized in networks of coactive cells, involving 2–16 cells located distantly and/or in clusters. We also report that spontaneous activity of small networks (2–6 Müller cells) repeat over time, sometimes in the same sequential order, revealing specific temporal dynamics. In addition, we show that networks of coactive glial cells are inhibited by TTX, indicating that ganglion and/or amacrine neuronal cells probably regulate Müller cell network properties. These results represent the first demonstration that spontaneous activity in adult Müller cells is patterned into correlated networks that display repeated sequences of coactivations over time. Furthermore, our bioluminescence technique provides a novel tool to study the dynamic characteristics of glial Ca²⁺ events in the retina under dark conditions, which should greatly facilitate future investigations of retinal dark-adaptive processes.