脊髓损伤模型大鼠神经胶质细胞增殖与胶质纤维酸性蛋白的表达

背景：星形胶质细胞可以通过细胞裂解释放各种神经营养因子,并可促进损伤脊髓的修复。 目的：观察脊髓损伤模型大鼠神经胶质纤维酸性蛋白的表达及对其后肢功能恢复的影响。 方法：将SD大鼠采用Allen's法撞击T9~10节段致脊髓损伤,造模成功后蛛网膜下腔移植骨形态发生蛋白7,并设置仅蛛网膜下腔移植His蛋白的正常SD大鼠做对照。用BBB评分法评估两组大鼠后肢的运动功能,用免疫组织化学染色法和Western-blot法观察各组神经胶质纤维酸性蛋白的表达。 结果与结论：BBB评分结果显示,模型组大鼠脊髓损伤后下肢功能自行恢复率达68%。模型组脊髓损伤3和7 d,损伤区域神经胶质纤维酸性蛋白表达逐渐增加(P  < 0.05),随后逐渐下降,于脊髓损伤28 d后逐渐恢复到对照组水平(P > 0.05)。脊髓损伤后1~14 d两组胶质纤维酸性蛋白表达逐渐升高(P > 0.05)。结果证实,脊髓损伤后蛛网膜下腔移植骨形态发生蛋白7可诱导星形胶质细胞增殖,神经胶质纤维酸性蛋白的表达增强,进而促进脊髓损伤大鼠后肢功能的恢复。     

鲍曼不动杆菌外膜蛋白A通过Akt/mTOR/p70S6K信号通路引起RAW264.7细胞自噬

目的:分析鲍曼不动杆菌标准株ATCC 19606(Acinetobacter baumannii ATCC 19606)外膜蛋白A(outer membrane protein A,Omp A)对RAW264. 7细胞的自噬诱导作用。方法:建立Omp A刺激RAW264. 7细胞的模型,通过细胞免疫荧光染色、Western blot和透射电子显微镜检测Omp A对RAW264. 7细胞自噬的影响。结果:Omp A可以引起自噬蛋白LC3B-II表达升高,并抑制Akt/mTOR/p70S6K的磷酸化水平;雷帕霉素可以进一步降低mTOR和p70S6K磷酸化,并提高Omp A引起的LC3B-II表达升高。结论:鲍曼不动杆菌Omp A通过Akt/mTOR/p70S6K信号通路引起RAW264. 7细胞自噬。这为将来进一步研究鲍曼不动杆菌引起自噬的分子机制及找到对抗其感染的新方法提供理论依据。     

山楂叶总黄酮调控星形胶质细胞治疗脊髓损伤的分子机制

背景：星形胶质细胞对脊髓损伤后神经元的修复具有重要作用,有研究证明山楂叶总黄酮可促进大鼠脊髓损伤后运动功能恢复,山楂叶总黄酮是否影响星形胶质细胞促进神经元修复仍不清楚。目的：探索山楂叶总黄酮调控星形胶质细胞治疗脊髓损伤的分子机制。方法：构建脊髓星形胶质细胞与脊髓神经元transwell共培养模型,对照组为正常脊髓星形胶质细胞和正常脊髓神经元;损伤组为正常脊髓星形胶质细胞和损伤脊髓神经元;药物组为125μg/mL山楂叶总黄酮干预的正常脊髓星形胶质细胞和损伤脊髓神经元。荧光探针DCFH-DA检测脊髓神经元内活性氧的生成;实时荧光定量PCR检测脑源性神经营养因子、神经生长因子、转录因子4的表达;Western blot检测脑源性神经营养因子、神经生长因子、Wnt/β-catenin通路关键蛋白GSK-3β、phsopho-GSK-3β(ser9)、β-catenin及转录因子4的表达;免疫荧光观察Wnt/β-catenin通路关键蛋白β-catenin的表达。结果与结论：(1)损伤组活性氧生成远高于对照组(P <0.001);药物组活性氧生成低于损伤组(P <0.01),高于对照...     

大鼠脊髓胶质瘢痕形成的规律*

背景：脊髓损伤后治疗不理想的原因是脊髓组织的囊变和胶质瘢痕的形成,因此,明确胶质瘢痕的发生发展规律具有重要意义。 目的：观察大鼠脊髓损伤后脊髓胶质瘢痕形成的空间分布、时间规律,以及轴突变化特征。 方法：采用改良Allen重物坠落法建立SD大鼠脊髓损伤模型,分别于损伤后1 d,3 d,5 d,1周,2周,4周,6周,8周,10周,12周取材。以正常饲养的大鼠作对照。 结果与结论：大鼠脊髓损伤后4周开始出现致密瘢痕增生,之后瘢痕厚度平稳下降,至损伤后10周形成光滑的囊腔壁,囊腔内无胶质纤维酸性蛋白阳性星形胶质细胞,损伤区囊腔周围的胶质瘢痕内可见密集肥大的星形胶质细胞,未见神经丝蛋白阳性轴突位于囊腔内。提示脊髓损伤后4周胶质瘢痕厚度达到高峰,囊腔与残存轴突之间开始形成机械屏障,损伤后10周瘢痕厚度趋于稳定。      

电针刺激对大鼠脊髓损伤部位神经胶质纤维酸性蛋白的影响

背景:神经胶质纤维酸性蛋白是一个中间丝过渡表达蛋白,其表达水平是最常用的星形胶质细胞的特异性标志蛋白。中医治疗脊髓损伤历史悠久,大量研究表明针刺"督脉""足阳明胃经"对脊髓损伤的神经再生修复具有一定作用。目的:观察电针刺激后脊髓损伤大鼠损伤部位神经胶质纤维酸性蛋白表达的变化,进一步探讨电针刺激对脊髓损伤大鼠神经再生的影响。方法:将120只SD大鼠随机分为5组,即督脉电针组、胃经电针组、混合电针组、模型对照组和假手术组,每组24只,除假手术组不进行脊髓切断外,其他各组均制备T₁₀脊髓半横断损伤模型。每个组再随机分为治疗后3,7,14,21 d组,每亚组6只。假手术组及模型对照组不进行干预,其他3个电针组进行相应电针干预。以免疫组化法检测损伤局部神经胶质纤维酸性蛋白阳性细胞的表达;PCR、Western blot检测神经胶质纤维酸性蛋白m RNA及蛋白的表达情况。结果与结论:(1)模型对照组损伤后神经胶质纤维酸性蛋白的表达水平呈先增高后降低的趋势,与未损伤的假手术组相比差异有显著性意义(P<0.05);(2)督脉电针组、胃经电针组与模型对照组相比,神经胶质纤维酸...     

miR-146a-3p抑制胰岛素样生长因子1表达调控星形胶质细胞增殖、迁移和凋亡

背景：mi R-146a-3p水平改变是大多数神经系统疾病发病机制中的常见事件，mi R-146a-3p调节星形胶质细胞的具体机制尚未被研究。目的：验证mi R-146a-3p通过胰岛素样生长因子1调控星形胶质细胞的增殖、迁移和凋亡。方法：将12只SD大鼠随机分为假手术组和脊髓损伤组，每组6只。术后2周对大鼠脊髓组织进行了RNA-Seq测序分析，筛选出差异基因(log2FC>2)，同时挑选出Genecards数据库中脊髓损伤相关基因(Score>20)，再通过Targetscan预测mi R-146a-3p的靶基因，取这3个基因集交集，筛选出胰岛素样生长因子1为其中一个重要的目的基因。q PCR、Western blot和免疫组化分析脊髓组织中胰岛素样生长因子1的表达水平。将原代星形胶质细胞分为NC组、NC-mimics组和mi R-146a-3p mimics组，用Annexin-V/PI染色法检测细胞凋亡情况、CCK-8法检测细胞增殖情况、Transwell法检测细胞的迁移能力。结果与结论：脊髓损伤组大鼠脊髓组织中mi R-146a-3p的表达较假手术组下降(P <...     

核因子-κB p65在神经病理性疼痛大鼠脊髓中的表达定位

目的研究核因子-κB(NF-κB)p65在神经病理性疼痛大鼠脊髓背角中的表达与定位。方法建立大鼠坐骨神经慢性压迫损伤(CCI)模型;应用Western blot法检测CCI大鼠脊髓NF-κB p65的表达情况;采用免疫荧光染色双标法检测NF-κB p65蛋白在CCI大鼠脊髓背角内的亚细胞(神经元、星形胶质细胞及小胶质细胞)定位。结果 CCI大鼠的机械阈值较正常大鼠显著降低;神经损伤后,NF-κB p65表达量在脊髓组织中显著增高;NF-κB p65主要定位于脊髓背角神经元和星形胶质细胞,而在小胶质细胞中没有表达。结论 NF-κB p65在CCI大鼠脊髓中相对高表达并主要定位于脊髓背胶神经元和星形胶质细胞。     

mTOR信号通路与细胞凋亡

哺乳类动物雷帕霉素靶蛋白(mTOR)主要通过上游信号转导通路磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(PKB/Akt)/mTOR信号通路及下游信号通路mTOR/ eIF4E结合蛋白1(4EBP1)、mTOR/p70S6激酶(p70S6K)在细胞生长、增值与分化和在血管再生、蛋白合成与降解中发挥作用.细胞凋亡是细胞的一种程序性死亡,在机体发育、组织代谢中有着重要作用,而细胞凋亡的异常调节与许多疾病的发生和发展紧密相连.近年研究发现,mTOR信号通路在细胞凋亡过程中扮演了重要角色,并已被作为新的药物治疗靶点.     

雷帕霉素激活自噬改善嘌呤霉素氨基核苷诱导的足细胞损伤

目的:通过观察雷帕霉素对PAN 诱导的足细胞损伤及自噬相关蛋白表达的影响,探讨自噬在雷帕霉素保护PAN 诱导的足细胞损伤中的作用及可能机制。方法:构建PAN 诱导的足细胞损伤模型,将足细胞分成对照组(Control 组),PAN 组(加入50 μg/ ml PAN),雷帕霉素组(RAP 组:分别加入100、200、300 ng/ ml 雷帕霉素),PAN+雷帕霉素组(PAN+RAP组:细胞在用含PAN 的培养液培养前1 h,分别用100、200、300 ng/ ml 雷帕霉素进行预处理1 h)。采用Annexin V/ PI 双染法检测细胞凋亡,透射电镜观察自噬小体,Western blot 检测LC3、p62、4EBP1、P70S6K、mTOR 蛋白表达。结果:与对照组比较,PAN组足细胞凋亡增加,自噬体减少,LC3域蛋白表达下调,p62 上调,mTOR、4EBP1、P70S6K 磷酸化水平上调;与PAN 组比较,PAN+RAP 组足细胞凋亡率下降,自噬体增加,LC3域蛋白表达上调,p62 下调,mTOR、4EBP1、P70S6K 磷酸化水平下调。结论:PAN 可以抑制足细胞自噬,促进足细胞凋亡;雷帕霉素可通过激活自噬改善PAN 诱导的足细胞损伤,这种作用可能与雷帕霉素抑制mTOR/4EBP1、P70S6K 信号通路有关。     

环状RNA-SETD2通过Akt/p70S6K1信号通路抑制滋养细胞的增殖、侵袭和促进凋亡

目的 观察环状RNA-SETD2(circ-SETD2)在巨大儿产妇胎盘组织中的作用,探讨其与Akt/p70S6K1信号通路的关系.方法 收集巨大儿产妇胎盘组织,qRT-PCR和FISH实验检测circ-SETD2的表达情况;构建circ-SETD2过表达质粒并转染HTR-8/SVneo滋养细胞,通过CCK8实验、Transwell实验和流式细胞术检测过表达circ-SETD2对细胞增殖、侵袭和凋亡的影响;Western blot检测Akt/p70S6K1信号通路相关蛋白表达情况.结果 与正常体重儿胎盘相比,circSETD2在巨大儿产妇胎盘组织中表达水平显著升高(P＜0.05).在滋养细胞HTR-8/SVneo中过表达circSETD2后,细胞增殖与侵袭能力显著降低,细胞凋亡率显著升高(P＜0.05),磷酸化Akt(p-Akt)和磷酸化p70S6K1(p-p70S6K1)蛋白水平显著降低(P＜0.05),但Akt和p70S6K1表达水平无显著性变化(P＞0.05).结论 circ-SETD2在巨大儿产妇胎盘组织中表达升高;circ-SETD2过表达后可通过调节Akt/p70S6K1信号通路抑制滋养细胞增殖和侵袭,促进凋亡.     

ATP-mediated protein kinase B Akt/mammalian target of rapamycin mTOR/p70 ribosomal S6 protein p70S6 kinase signaling pathway activation promotes improvement of locomotor function after spinal cord injury in rats

The protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/p70 ribosomal S6 protein kinase (p70S6K) signaling pathway, as a central controller of cell growth, proliferation, survival, and differentiation in response to extracellular signals, growth factors, nutrient availability, energy status of the cell, and stress, has recently gained attention in neuroscience. The effects of this signaling pathway on repair of spinal cord injury (SCI), however, have not been well elucidated. ATP is increasingly recognized as an important regulator of signal transduction pathways, and plays important roles in functional recovery after nervous system injury. In the present study, we examined the ATP-induced changes of the Akt/mTOR/p70S6K signaling pathway in injured spinal cord of adult rats and potential therapeutic effects of this pathway on SCI-induced locomotor dysfunction. SCI was produced by extradural weight-drop using modified Allen's stall with damage energy of 50 g-cm force. The rats were divided into four groups: SCI plus ATP, SCI plus saline, SCI plus ATP and rapamycin, and sham-operated. Using immunostaining studies, Western blot analyses and real-time qualitative RT-PCR analyses, we demonstrated that the Akt/mTOR/p70S6K signaling pathway is present in the injured spinal cord and the expression of its components at the protein and mRNA levels is significantly elevated by exogenous administration of ATP following SCI. We observed the effectiveness of the activated Akt/mTOR/p70S6K signaling pathway in improving locomotor recovery, significantly increasing the expression of nestin, neuronal nuclei (NeuN), neuron specific enolase (NSE), and neurofilament 200 (NF200), and relatively inhibiting excessive reactive astrogliosis after SCI in a rapamycin-sensitive manner. We concluded that ATP injection produced a significant activation of the Akt/mTOR/p70S6K signaling pathway in the injured spinal cord and that enhancement of rapamycin-sensitive signaling produces beneficial effects on SCI-induced motor function defects and repair potential. We suggest that modulation of this protein kinase signaling pathway activity should be considered as a potential therapeutic strategy for SCI.     

IL2-dependent phosphorylation of 40S ribosomal protein S6 is controlled by PI-3K/mTOR signalling in CTLL2 cells

Growth factors and hormones activate global and selective protein translation by phosphorylation and therefore activation of p70 S6 kinase through a wortmannin-sensitive phosphoinositide-3 kinase (PI-3K) antiapoptotic pathway and a rapamycin-sensitive signalling pathway of mTOR. Here we demonstrate that the phosphorylation of 40S ribosomal protein S6, a physiological substrate p70 S6 kinase, was highly increased by growth-stimulation of the cytolytic T cells (CTLL2) with interleukin 2 (IL2), which was accompanied with the increased phosphorylation of p70 S6K. The activity of p70 S6K and phosphorylation of the S6 protein was completely blocked by rapamycin and significantly decreased upon treatment of the cells with wortmannin, indicating an involvement of the PI-3K pathway in concert with the signalling pathway of mTOR in IL2-dependent phos-phorylation of ribosomal protein S6. The phosphorylation and activity of PKB/Akt in IL2-stimulated CTLL2 cells were rapamycin-insensitive and reduced upon wortmannin treatment of the cells, confirming a requirement for PI-3K for Akt activity. The data support the hypothesis that Akt may act downstream to PI-3K and upstream to mTOR in an IL2-mediated signal transduction pathway that controls phosphorylation of the regulatory protein S6 in CTLL2 cells.     

Serotonin-induced growth of pulmonary artery smooth muscle requires activation of phosphatidylinositol 3-kinase/serine-threonine protein kinase B/mammalian target of rapamycin/p70 ribosomal S6 kinase 1

We have previously found that both mitogen-activated protein kinase (MAPK)- and Rho kinase (ROCK)-related signaling pathways are necessary for the induction of pulmonary artery smooth muscle cell (SMC) proliferation by serotonin (5-hydroxytryptamine [5-HT]). In the present study, we investigated the possible additional participation of a phosphatidylinositol 3-kinase (PI3K)/serine-threonine protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/p70 ribosomal S6 kinase (S6K1) pathway in this growth response. We found transient activation of Akt (Ser473) and more prolonged activation of S6K1 by 5-HT. Inhibition of PI3K with Wortmannin and LY294002 completely blocked these activations, but not that of MAPK or the ROCK substrate myosin phosphatase targeting subunit. Similarly, inhibition of MAPK and ROCK failed to block the Akt activation. Inhibition of Akt with NL-71-101 and downregulation of Akt expression with Akt small interfering RNA blocked 5-HT-induced S6K1 phosphorylation. Wortmannin, LY294002, and NL-71-101 dose-dependently inhibited 5-HT-induced SMC proliferation. 5-HT stimulated mTOR phosphorylation and the mTOR inhibitor, rapamycin, blocked activations of S6K1 and S6 ribosomal protein, and inhibited 5-HT-induced SMC proliferation. Akt phosphorylation and cell proliferation were also blocked by the antioxidants, N-acetyl-l-cysteine, Ginko biloba 501, and tiron, the reduced nicotinamide adenine dinucleotide phosphate oxidase inhibitor, diphenyleneiodonium, and the 5-HT2 receptor antagonists ketanserin and mianserin, but not by the 5-HT serotonin transporter or 5-HT 1B/1D receptor antagonists. We conclude from these studies that a parallel PI3K- and reactive oxygen species-dependent Akt/mTOR/S6K1 pathway participates independently from MAPK and Rho/ROCK in the mitogenic effect of 5-HT on pulmonary artery SMCs. From these and other studies, we postulate that independent signaling pathways leading to 5-HT-induced SMC proliferation are initiated through multiple 5-HT receptors and serotonin transporter at the cell surface.     

Estradiol attenuates the focal cerebral ischemic injury through mTOR/p70S6 kinase signaling pathway

We previously showed that estradiol prevents neuronal cell death through the activation of Akt and its downstream targets Bad and FKHR. This study investigated whether estradiol modulates the survival pathway through other downstream targets of Akt, including mammalian target of rapamycin (mTOR) and p70S6 kinase. It is known that mTOR is a downstream target of Akt and a central regulator of protein synthesis, cell growth, and cell cycle progression. Adult female rats were ovariectomied and treated with estradiol prior to middle cerebral artery occlusion (MCAO). Brains were collected 24h after MCAO and infarct volumes were analyzed. We confirmed that estradiol significantly reduces infarct volume and decreases the number of positive cells for TUNEL staining in the cerebral cortex. Brain injury-induced a decrease in phospho-mTOR and phospho-p70S6 kinase. Estradiol prevented the injury-induced decrease in Akt activation and phosphorylation of mTOR and p70S6 kinases, and the subsequent decrease in S6 phosphorylation. Our findings suggest that estradiol plays a potent protective role against brain injury by preventing the injury-induced decrease of mTOR and p70S6 kinase phosphorylation.     

IL-1β通过PI3K/Akt/mTOR途径促进神经元活化

目的:观察白细胞介素-1β(IL-1β)刺激对神经元活化的影响。方法:利用IL-1β刺激体外培养的原代神经元,运用慢病毒转染shRNA使PI3K的p85亚基(PI3K-p85)沉默、哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,m TOR)抑制剂雷帕霉素预处理阻断m TOR、酪氨酸激酶家族抑制剂PP2抑制p85向IL-1受体I型(IL-1RI)募集等方式预处理神经元,检测PI3K-p85、与IL-1RI结合的PI3K-p85、p-Akt、p-p70S6K以及微管相关蛋白2(MAP2)在神经元内的变化及相互作用;利用FM4-64染色观察各组神经元突触胞吞情况。结果:利用IL-1β刺激体外培养的海马神经元可增加细胞内PI3K-p85、p-Akt、p-p70S6K、MAP2以及与IL-1RI结合的PI3K-p85的水平(P0.05),并且神经元突触的胞吞作用明显加剧(P0.05);抑制PI3K-p85可以下调IL-1β所致的p-Akt、pp70S6k和MAP2水平增加(P0.05),神经元突触的胞吞作用减弱(P0.05);抑制m TOR也能下调IL-1β所致的PI3K-p85、p-Akt、p-p70S6K和MAP2水平增加(P0.05),神经元突触的胞吞作用减弱(P0.05);抑制p85亚基与IL-1RI的结合也可以下调IL-1β所致的p-Akt、p-p70S6K和MAP2水平增加(P0.05)。结论:促炎因子IL-1β通过IL-1RI与PI3K-p85结合使PI3K-p85活化,进而磷酸化Akt和m TOR下游物质p70S6K,促进神经元突触增生及活化,这可能是内侧颞叶癫痫向慢性化进展的机制之一。     

Melatonin prevents ischemic brain injury through activation of the mTOR/p70S6 kinase signaling pathway

We previously reported that melatonin prevents neuronal cell death in ischemic brain injury through the activation of Akt and the inhibition of apoptotic cell death. We investigated whether melatonin inhibits the apoptotic signal through the activation of a mammalian target of rapamycin (mTOR) and p70S6 kinase and its downstream target, S6 phosphorylation. It is known that mTOR is a downstream target of Akt and a central regulator of protein synthesis, cell growth, and cell cycle progression. Adult male rats were treated with melatonin (5mg/kg) or vehicle prior to middle cerebral artery occlusion (MCAO). Brains were collected at 24h after MCAO and infarct volumes were analyzed. We confirmed that melatonin significantly reduces infarct volume and decreases the number of TUNEL-positive cells in the cerebral cortex. Brain injury induced a decrease in phospho-mTOR and phospho-p70S6 kinase. Melatonin prevented the injury-induced decrease in Akt activation and phosphorylation of mTOR and p70S6 kinases, and the subsequent decrease in S6 phosphorylation. Our results suggest that melatonin prevents cell death resulting from ischemic brain injury and that its neuroprotective effects are mediated by preventing the injury-induced decrease of mTOR and p70S6 kinase phosphorylation.     

Paradigm of kinase-driven pathway downstream of epidermal growth factor receptor/Akt in human lung carcinomas

The expression/activation of epidermal growth factor receptor (EGFR) and the correlation with the phosphorylation status of downstream modulator proteins, Akt, mammalian target of rapamycin (mTOR), p70S6-kinase (S6K), ribosomal protein S6 (rS6), and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), were analyzed and EGFR/Akt signaling was evaluated in lung carcinomas. Immunohistochemical analysis of 140 cases revealed overexpression of EGFR in 37.9% and phosphorylation in 37.1%, but much less in small cell carcinoma. Combined analysis with immunoblotting revealed that when EGFR is activated, at least one of the mTOR/S6K or mTOR/4E-BP1 cascades was activated in 60% of the cases. Furthermore, constitutive activation of EGFR-Akt-mTOR was found in 17.9% of nonsmall cell lung carcinomas (NSCLCs). For each protein, the frequencies of the activation vary among histologic types. In adenocarcinoma (AC), 90% revealed mTOR activation regardless of EGFR status, and 60% of these showed activation of downstream S6K/rS6. Furthermore, mutation of EGFR was frequently accompanied by phosphorylation of EGFR and constitutive activation of entire EGFR through rS6 was observed in 50% of carcinoma harboring EGFR mutation, including squamous cell carcinoma (SCC). By clinicopathologic analysis, Akt activation was correlated with lymph node metastasis in general, but nodal metastasis was correlated with rS6 activation in AC and with mTOR activation in SCC. In conclusion, (i) constitutive activation of EGFR/Akt/mTOR pathway was present in defined subset of NSCLC; (ii) mTOR/S6K/rS6 axis is frequently activated in AC, and constitutively activated through Akt by EGFR mutation even in SCC; and (iii) mTOR and rS6 are possible determinants of nodal metastasis in SCC and AC, respectively.     

The effect of MK-801 on mTOR/p70S6K and translation-related proteins in rat frontal cortex

In experimental animals, including rats, MK-801 produces characteristic behavioural changes that model schizophrenia. It has been hypothesized that these changes accompany long-term synaptic changes, which require protein neosynthesis. We observed the effect of MK-801 on the “mammalian target of rapamycin” (mTOR)/70-kDa ribosomal protein S6 kinase (p70S6K) pathway that regulates protein synthesis in the rat frontal cortex. A single injection of MK-801 (0.5, 1, or 2 mg/kg) induced an acute increase in the phosphorylation of Akt (Ser-473) eIF4E-binding protein (4E-BP1) (Thr-37/46) and p70S6K (Thr-389). In contrast, after repeated treatment with MK-801 (1 mg/kg for 5 or 10 days), the phosphorylation of Akt (Ser-473), mTOR (Ser-2481), 4E-BP1 (Thr-37/46), p70S6K (Thr-389), and S6 (Ser-240/244) increased. Thus, proteins in the mTOR/p70S6K pathway are modulated in chronic MK-801 animal models. These findings may suggest that repeated MK-801 treatment activates the signal transduction pathways involved in the initiation of protein synthesis in the rat frontal cortex.