【作者】 宋静；

【导师】 牛侨；

【作者基本信息】 山西医科大学 ， 劳动卫生与环境卫生学， 2014， 博士

【摘要】 第一部分：急性、亚慢性铝暴露对大鼠海马LTP损害作用及对AMPA受体外化的影响从本课题组的前期研究结果发现，在亚慢性染铝致大鼠学习记忆损害的动物模型中，海马细胞内AMPA受体亚单位的表达量降低，说明AMPA受体与铝损害学习记忆的机制有关。同时AMPA受体作为LTP的主要表达机制，我们有理由认为AMPA受体可能是铝损害LTP机制之一。所以，本项目拟通过急性和亚慢性铝暴露，观察不同剂量铝对大鼠海马LTP的影响，以及在损害LTP的情况下，AMPA受体外化（AMPA受体亚基GluR1、GluR2分别在胞膜和总蛋白中蛋白表达量）的改变，为阐明铝损害LTP的机制研究提供有力的实验依据。第一章急性铝暴露对大鼠海马LTP的影响目的：探讨急性铝暴露对大鼠海马LTP的影响。方法：对照组、低、中、高染铝组大鼠通过侧脑室给药的方式分别一次性接受生理盐水、2.43μg Al(mal)3、12.15μg Al(mal)3和60.75μug Al(mal)3，给药容积为5μl，5min内缓慢匀速注入。采用在体海马CA1区LTP及PPF记录技术，记录fEPSP。结果：各个剂量组在给药前和给药后5min、15min、30min的fEPSP幅度变化不大，无统计学差异(P>0.05)；侧脑室内注射生理盐水及不同剂量Al(mal)3后不影响PPF，与注射前相比没有显著性差异(P>0.05)， Al(mal)3未对突触前释放产生影响；对照组在高频刺激后fEPSP即刻增大至（221±10）%，1h后仍保持在（190±27）%，但注射了Al(mal)3的中高剂量组在在高频刺激后fEPSP即刻增大的幅度仅为（165±21）%和（149±8）%，在1h之后，中剂量组fEPSP幅度仅保持在（140±13）%，高剂量组fEPSP幅度几乎回到了高频刺激前的基础水平（110±7）%，与对照组组比显著降低（P<0.05），低剂量组虽然在高频刺激后fEPSP即刻增大的幅度达到了（194±19）%，与对照组无差别(P>0.05)，但在30min及1h后，幅度降低到了（164±13）%和（157±8）%，比对照组明显降低，由此可见，Al(mal)3对LTP的诱导与维持的抑制成明显的剂量依赖性。结论： Al(mal)3对LTP的诱导与维持的有明显的抑制作用，并呈现出显著的剂量依赖性，这可能与铝损害突触后机制（如，NMDAR、AMPAR等谷氨酸受体）有关。第二章急性铝暴露对大鼠海马AMPA受体外化的影响目的：探讨急性铝暴露对海马AMPA受体外化的影响。方法：对照组、低、中、高染铝组大鼠通过侧脑室给药的方式分别一次性接受生理盐水、2.43μg Al(mal)3、12.15μgAl(mal)3和60.75ug Al(mal)3，给药容积为5μl，5min内缓慢匀速注入。在电生理实验结束后断头取海马，分别提取总蛋白和膜蛋白，采用Western-blot的方法检测AMPA受体亚单位GluR-1、GluR-2的蛋白表达水平。结果：总蛋白中，低、中、高染铝组上述两种亚单位的蛋白表达量无变化，且与对照组相比，无统计学差异（P>0.05）；膜蛋白中，低、中、高染铝组上述两种亚单位的蛋白表达量呈逐下降的趋势，且与对照组相比，有统计学差异（P<0.05）。结论：急性铝暴露未影响AMPA受体的蛋白合成，但抑制了AMPA受体从胞浆向胞膜的转运（外化）。第三章亚慢性铝暴露对大鼠海马LTP的影响目的：探讨亚慢性铝暴露对大鼠海马LTP的影响。方法：健康成年雄性SD大鼠24只，按体重随机分为4组：生理盐水、低剂量组Al(mal)3（0.41mg/kg）、中剂量组Al(mal)3（0.82mg/kg）与高剂量组Al(mal)3（1.23mg/kg），腹腔注射染毒8周后，采用在体海马CA1区LTP记录技术，记录fEPSP。结果：对照组在高频刺激后fEPSP即刻增大至（191±9）%，30min时保持在（154±15）%，60min后降低到（139±12）%；低剂量组fEPSP幅度在高频刺激后1min、30min、60min时的幅度分别为（195±17）%、（153±21）%和（131±18）%，与对照组比较，无统计学差异（P>0.05）；中剂量组fEPSP幅度在高频刺激后1min、30min、60min时的幅度分别为（176±21）%、（132±20）%和（117±7）%，与对照组比较，30min、60min时的幅度有统计学差异（P <0.05），与低剂量组比较30min时的幅度有统计学差异（P<0.05）；高剂量组fEPSP幅度在高频刺激后1min、30min、60min时的幅度分别为（175±40）%、（106±5）%和（85±10）%，与对照组比较，30min、60min时的幅度有统计学差异（P<0.05），与低剂量组比较30min、60min时的幅度有统计学差异（P<0.05），与中剂量组比较30min、60min时的幅度有统计学差异（P<0.05）。结论：亚慢性铝暴露对大鼠海马CA1区LTP呈显著的抑制作用，并成一定的剂量依赖性。第四章亚慢性铝暴露对大鼠海马AMPA受体蛋白外化的影响目的：探讨亚慢性铝暴露对海马AMPA受体外化的影响。方法：健康成年雄性SD大鼠24只，按体重随机分为4组：生理盐水、低剂量组Al(mal)3（0.41mg/kg）、中剂量组Al(mal)3（0.82mg/kg）与高剂量组Al(mal)3（1.23mg/kg），腹腔注射染毒8周，在电生理实验结束后断头取海马，分别提取总蛋白和膜蛋白，采用Western-blot的方法检测AMPA受体亚单位GluR-1、GluR-2的蛋白表达水平。结果：总蛋白中，高剂量组GluR-1蛋白表达量且与对照组相比，显著降低（P <0.05），中、高剂量组的GluR-2蛋白表达量与对照组比较明显降低（P<0.05），且高剂量组的GluR-2蛋白表达量与低剂量组相比降低明显（P <0.05）；膜蛋白中，两种亚单位的蛋白表达量随着染毒剂量的增加呈逐渐下降的趋势，中、高剂量组GluR-1、 GluR-2蛋白表达量且与其对照组相比，显著降低（P<0.05），且高剂量组的GluR-1蛋白表达量与低剂量组相比降低明显（P<0.05）。结论：亚慢性铝暴露不但抑制了AMPA受体从胞浆向胞膜的转运（外化），而且也抑制了AMPA受体的合成。第二部分铝损害AMPA受体外化的信号转导机制研究从本文第一部分的研究结果来看，AMPA受体参与铝损害大鼠海马LTP的发生机制，而其信号转导机制还不清楚。本部分研究拟采用在体电生理技术、western-blot和ELISA方法观察在急性铝暴露的情况下，伴随LTP损害情况下，RAS、MAPK、PI3K通路各个信号分子的表达情况，以及使用RAS活化剂的情况下，LTP及各个信号分子的变化。通过此次研究初步阐明AMPA受体外化在铝损害大鼠海马LTP中的作用及其信号转导机制，为铝致学习记忆损伤的机制研究及未来的干预研究提供有力的依据。第一章RAS在铝致大鼠LTP损害过程中的作用研究第一节急性铝暴露对大鼠海马RAS活性的影响目的：探讨急性铝暴露对大鼠海马RAS蛋白活性的影响。方法：对照组、低、中、高染铝组大鼠通过侧脑室给药的方式分别一次性接受生理盐水、2.43μg Al(mal)3、12.15μgAl(mal)3和60.75μg Al(mal)3，给药容积为5μl，5min内缓慢匀速注入。在电生理实验LTP测定结束后，断头取海马提蛋白，采用ELISA法测定RAS蛋白活性。结果：随着染铝剂量的增加，RAS活性呈逐渐下降的趋势，经统计学分析，与对照组比较，中、高剂量组的RAS活性显著下降（P<0.05）。结论：急性铝暴露会抑制RAS蛋白的活性，RAS活性的降低可能与铝损害LTP有密切关系。第二节RAS活化剂EGF在铝致大鼠LTP损害中的拮抗作用研究目的：探讨RAS活化剂EGF在铝致大鼠LTP损害的拮抗作用。方法：健康成年雄性SD大鼠24只，按体重随机分为4组：对照组（生理盐水）、EGF组.、Al+EGF组与Al组。采用侧脑室注射的方式一次性给予对照组大鼠5μl生理盐水，给予EGF组大鼠60ngEGF，给予Al+EGF组大鼠12.15μgAl和60ngEGF，给予Al组大鼠12.15μgAl。采用在体海马CA1区LTP记录技术，记录fEPSP。在电生理实验LTP测定结束后，断头取海马提蛋白，采用ELISA法测定RAS蛋白活性。结果：高频刺激后，对照组fEPSP幅度立即升高到（191±25）%，30min时保持在（179±22）%，60min后仍能保持在（156±27）%，而单纯染铝组fEPSP幅度在1min时为（160±4）%，在30min时持续下降到（132±15）%，而到60min时已完全恢复致基线水平（115±12）%，说明12.15ugAl显著的抑制了LTP的诱导和维持，这与我们第一部分第一章的结果相一致。EGF作为RAS的活化剂，我们在观察它是否会拮抗Al对LTP的抑制作用之前，我们首先观察了单独使用EGF是否会引起LTP的变化。结果显示，60ngEGF组高频刺激后fEPSP幅度在1min、20min时分别是（224±28）%和（189±14）%，与对照组比较幅度升高很明显（P<0.05），但到了30min、40min、60min时，fEPSP幅度与对照组一致，无明显差别（P>0.05）。此结果显示，EGF可以增强早期的LTP诱导，但到了后期作用减弱。最后我们联合使用了12.15ugAl和60ng EGF，结果我们惊喜的发现，EGF可以拮抗Al导致的LTP损害，在高频刺激后的1min、20min时，12.15ug Al+60ng EGF组fEPSP幅度分别为（183±5）%和（158±15）%，与单独使用12.15ugAl组比较，有了明显的上升（P <0.05），但到了30min、40min、60min时，fEPSP幅度与12.15ugAl组一致，无明显差别（P>0.05）。此结果说明EGF可以拮抗Al对LTP诱导的早期损害，但到了后期，这种拮抗作用减弱。结论：RAS活化剂的EGF可以拮抗急性铝暴露致LTP早期损害作用，急性铝暴露致大鼠海马LTP损害与RAS蛋白活性降低有关。第二章PI3K/PKB通路在铝致大鼠LTP损害过程中的作用研究目的：探讨PI3K/PKB通路在铝致大鼠LTP损害过程中的作用。方法：健康成年雄性SD大鼠24只，按体重随机分为4组：对照组（生理盐水）、EGF组.、Al+EGF组与Al组。采用侧脑室注射的方式一次性给予对照组大鼠5μl生理盐水，给予EGF组大鼠60ngEGF，给予Al+EGF组大鼠12.15μgAl和60ngEGF，给予Al组大鼠12.15ugAl。在电生理实验LTP测定结束后，断头取海马提蛋白，采用ELISA法测定PKB蛋白活性，采用western-blot法测定GluR1S831和S845位点磷酸化水平。结果：与对照组比较，单独给予12.15μg Al后，PKB活性明显下降（P <0.05），单独给予60ng EGF后，PKB活性明显升高（P <0.05），当联合给予12.15μgAl和60ng EGF后，与单独染铝组相比，PKB活性又有明显的回升（P<0.05）；与对照组比较，单独给予12.15μg Al后，GluR1S831和S845位点磷酸化水平明显下降（P <0.05），单独给予60ng EGF后，其磷酸化水平明显升高（P <0.05），当联合给予12.15μgAl和60ng EGF后，与单独染铝组相比，其磷酸化水平又有明显的回升（P <0.05）。结论：铝可能通过RAS-PI3K信号转导通路致AMPA受体磷酸化障碍，进而影响AMPA受体外化，最终表现出LTP的诱导受到抑制。第三章MAPK/ERK通路在铝致大鼠LTP损害过程中的作用研究目的：探讨MAPK/ERK通路在铝致大鼠LTP损害过程中的作用。方法：健康成年雄性SD大鼠24只，按体重随机分为4组：对照组（生理盐水）、EGF组.、Al+EGF组与Al组。采用侧脑室注射的方式一次性给予对照组大鼠5ul生理盐水，给予EGF组大鼠60ngEGF，给予Al+EGF组大鼠12.15μgAl和60ngEGF，给予Al组大鼠12.15μgAl。在电生理实验LTP测定结束后，断头取海马提蛋白，采用ELISA法测定ERK蛋白活性。结果：与对照组比较，单独给予12.15μgAl后，ERK活性明显下降（P <0.05），单独给予60ng EGF后，ERK活性明显升高（P <0.05），当联合给予12.15μgAl和60ng EGF后，与单独染铝组相比，ERK活性又有明显的回升（P <0.05）。结论：铝可抑制RAS-MAPK信号转导通路。但由于未检测GluR2L S841的磷酸化水平，所以还不能确定RAS-MAPK信号转导通路是否可致AMPA受体磷酸化障碍，从而导致LTP受到抑制。结论：急性及亚慢性铝暴露均会损害大鼠海马LTP的诱导和维持，这种损害的程度与铝的剂量有关，即呈现一定的剂量反应关系。铝通过抑制AMPA受体亚单位的外化及合成从而损害大鼠海马LTP的诱导和维持。“RAS→PI3K/PKB→GluR1S831和S845位点磷酸化→GluR1插入突触”通路与铝损害大鼠海马LTP有关。RAS→MAPK/ERK信号转导通路与铝损害大鼠海马LTP有关，但是否是通过引起AMPA受体磷酸化异常进而影响AMPA受体外化最终导致LTP损害的还有待于进一步研究。更多还原

【Abstract】 PartⅠ The damage of acute and subchronic aluminum exposure onhippocampal LTP and AMPA receptor trafficking in ratsAlpha-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA)-type glutamatereceptors (AMPAR) are multimeric proteins composed of GluR1, GluR2, GluR3, and GluR4subunits that mediate the majority of fast excitatory transmission in the central nervous system.The trafficking of GluR1and GluR2from intracellular pools to synaptic sites alters synapticstrength and has been recognized as a central mechanism of LTP. Since Al has been reportedaffecting LTP, may it be related to AMPAR? However, few studies on the effects of Al onAMPAR have been performed. Surprisingly, in a previous study, we observed decreasedexpression of glutamate receptors, including AMPARs, in the hippocampus after subchronic Alexposure in rats.On the basis of the previous study on the effects of Al on AMPAR and the possibleinvolvement of AMPAR in LTP, the present study was aimed to investigate the effects of acuteand subchronic treatment with different doses of aluminum-maltolate complex (Al (mal)3) onLTP and the total and membrane levels of the GluR1and GluR2AMPAR subunits in the rathippocampus. Here, a possible link between LTP dysfunction and AMPAR expression followingAl exposure was also explored.Chapter Ⅰ Effects of acute Al exposure on LTP in ratsObjective To explore the effects of acute Al exposure on LTP in rats. Methods Theexperiments were performed on24adult male rats (weight220-250g) that were kept underconstant temperature and humidity conditions with free access to food and water. The rats wererandomly divided into four groups (6rats/group): control group, low-dose group, medium-dosegroup and high-dose group. The rats received one dose of5μL of saline (control group) or a single dose of Al(mal)3(2.43,12.15or60.75μg Al) over5min via intracerebroventricular (i.c.v.)injection. fEPSP in CA1region were recorded by field potentiation technique in vivo. Results The basalfEPSP of60.75ug grops in preinjection and in postinjection were （109±4）%and（111±7）%respectively, no significant difference（P>0.05）. The fEPSP amplitudes of the control group were221%±10%,195%±30%and190%±27%at1,30and60min after HFS, respectively. Theaverage fEPSP amplitudes of the2.43μg Al group were164%±13%at30min and157±8%at60min after HFS, which represented a slight but statistically significant decrease compared to thecontrol group (P<0.05); these values dropped to165%±21%,155%±11%and140%±13%in the12.15μg Al group (P<0.05) and further decreased to149%±8%,139%±12%and110%±7%inthe60.75μg Al group (P<0.05). Notably, the suppression of LTP by Al was apparent between theAl and control groups (P<0.05), and further suppression was apparent with increasing Alconcentrations. At same time, Al(mal)3did not affect paired pulse facilitation（PPF）ratio（P>0.05）. Conclusion Acute Al treatment obviously suppressd the LTP in rat hippocampal CA1region in a dose-dependent manner in vivo, probably through postsynaptic mechanism but notpresynaptic transmitter release.Chapter Ⅱ Effects of acute Al exposure on AMPA receptors trafficking in ratsObjective To explore the effects of acute Al exposure on AMPA receptors trafficking inrats. Methods Animals and treatments were same with chapterⅠ. The expression of AMPARsubunit proteins (GluR1and GluR2) in both total and membrane-enriched extracts from the CA1area of rat hippocampus were detected by Western blot assay. Results None of the threedosages (2.43,12.15and60.75μg of Al) of Al(mal)3induced significant changes in GluR1(P>0.05) or GluR2(P>0.05) in the total extracts. However, significant decreases in GluR1(P<0.05) and GluR2(P<0.05) were found in the membrane-enriched extracts. With increasing Alconcentrations, the expressions of GluR1and GluR2proteins gradually decreased. Comparedwith the control group, the GluR1and GluR2levels of12.15μg Al group and the60.75μg Algroup were significantly decreased (P<0.05). Conclusion Acute Al treatment produceddose-dependent decreases of GluR1and GluR2in membrane extracts but not in total extracts,suggesting that the trafficking of AMPA receptor subunits from intracellular pools to synapticsites during HFS-induced LTP was suppressed.Chapter Ⅲ Effects of subchronic Al exposure on LTP in ratsObjective To explore the effects of subchronic Al exposure on LTP in rats. Methods Theexperiments were performed on24adult male rats that were kept under constant temperature and humidity conditions with free access to food and water. The rats were randomly divided into fourgroups (6rats/group): control group, low-dose group, medium-dose group and high-dose group.The rats received saline (control group) or Al(mal)3(0.41,0.82, or1.23mg/kg) viaintraperitoneal (i.p.) injection for8weeks. Hippocampal LTP in CA1region were recorded byfield potentiation technique in vivo. Results The fEPSP amplitudes of the control group were154%±15%and139%±12%at30and60min after HFS, respectively. The average fEPSPamplitudes of the0.41mg/kg Al group were153±21%and131±18%at the same time, whichrepresented no significant decrease compared with the control group (P>0.05); these valuesdropped to132%±20%and117%±7%in the0.82mg/kg Al group (P<0.05) and furtherdecreased to106%±40%and85%±10%in the1.23mg/kg Al group (P<0.05). Notably, thesuppression of LTP by Al was apparent between the Al and control groups (P<0.05), and furthersuppression was apparent with increasing Al concentrations. Conclusion Subchronic Altreatment obviously suppressd the LTP in rat hippocampal CA1region in a dose-dependentmanner in vivo.Chapter Ⅳ Effects of subchronic Al exposure on AMPA receptors trafficking in ratsObjective To explore the effects of subchronic Al exposure on AMPA receptors trafficking inrats. Methods Animals and treatments were same with chapterⅢ. The expression of AMPARsubunit proteins (GluR1and GluR2) in both total and membrane-enriched extracts from the CA1area of rat hippocampus were detected by Western blot assay. Results In contrast to the acuteexperiment, subchronic Al treatment caused dose-dependent decreases in GluR1and GluR2thatwere not restricted to the membrane extracts(P<0.05), but were present in the total extracts (P<0.05). Compared with the control group, the GluR-1level of the1.23mg/kg Al group and theGluR-2levels of the0.82mg/kg Al and1.23mg/kg Al groups decreased gradually in the totalextracts (P<0.05). Similarly, in the membrane-enriched extracts, the GluR-1and GluR-2levelsof the0.82mg/kg Al and1.23mg/kg Al groups also decreased gradually (P<0.05). ConclusionSubchronic Al treatment produced dose-dependent decreases of GluR1and GluR2both inmembrane extracts and in total extracts, suggesting that the trafficking of AMPA receptor and theexpression of AMPA receptor subunit proteins was suppressed.PartⅡ Study on involvement of signal transduction pathway of AMPAreceptor trafficking in aluminum-induced impairment of hippocampal LTP inratsOn the basis of the previous study of the possible involvement of AMPAR in the damage on hippocampal LTP by aluminum, the present study was aimed to investigate the signaltransduction pathway of AMPA receptor trafficking.ChapterⅠThe role of RAS in the damage on hippocampal LTP by aluminum in ratsSection1Effects of acute aluminum exposure on RAS activity in rats hippocampusObjective To explore the effects of acute Al exposure on RAS activity in rats hippocampus.Methods The experiments were performed on24adult male rats that were kept under constanttemperature and humidity conditions with free access to food and water. The rats were randomlydivided into four groups (6rats/group): control group, low-dose group, medium-dose group andhigh-dose group. The rats received one dose of5μL of saline (control group) or a single dose ofAl(mal)3(2.43,12.15or60.75μg Al) over5min via intracerebroventricular (i.c.v.) injection.Following electrophysiological recordings, the test of RAS activity were conducted by ELISA.Results With the increase of Al exposed dose, RAS activity decreased gradually. Compared withthe control group, the RAS activity of the medium-dose and high-dose group decreasedsignificantly (P<0.05). Conclusion Acute Al treatment obviously suppressd the RAS activity ofrat hippocampus during HFS-induced LTP was suppressed.Section2The antagonism of RAS activator EGF on suppression of hippocampal LTP byaluminumObjective To explore the antagonism of RAS activator EGF on hippocampal LTP suppressedby aluminum. Methods The experiments were performed on24adult male rats that wererandomly divided into four groups (6rats/group): control group, EGF group, EGF+Al groupand Al group. The rats received one dose of5μL of saline (control group),60ng EGF （EGFgroup）,12.15μg Al+60ng EGF (EGF+Al group),12.15μg Al (Al group) over5min viaintracerebroventricular (i.c.v.) injection. Hippocampal LTP in CA1region was recorded by fieldpotentiation technique in vivo. Results The fEPSP amplitudes of the control group were194%±25%,179%±22%and156%±27%at1,30and60min after HFS, respectively; Theaverage fEPSP amplitudes of the Al group were160%±4%,132%±15%and115%±12%at thesame time, which represented a statistical decrease compared with the control group (P<0.05);The average fEPSP amplitudes of the EGF group were224%±28%and189%±14%at1,20min after HFS, which represented a statistical increase compared with the control group (P<0.05), but on difference was found at30,40,60min after HFS(P>0.05);The average fEPSPamplitudes of the EGF+Al group were183%±5%and158%±15%at1,20min after HFS, which represented a statistical return compared with the Al group (P<0.05), but on difference wasfound at30,40,60min after HFS(P>0.05). Conclusion The RAS activator EGF couldantagonize the early suppression of hippocampal LTP by aluminum.Chapter Ⅱ The role of PI3K/PKB signal transduction pathway of AMPA receptortrafficking in the damage on hippocampal LTP by aluminum in ratsObjective To explore the role PI3K/PKB signal transduction pathway of AMPA receptortrafficking in the damage on hippocampal LTP by aluminum in rats. Methods Animals andtreatments were same with chapterⅠsection2. Following electrophysiological recordings, thephosphorylation of GluR1S831和S845and the PKB activity of rat hippocampus were detectedby Western blot assay and ELISA. Results Compared with the control group, thephosphorylation of GluR1S831和S845and the PKB activity of Al group significantlydecreased (P<0.05), but these values of EGF group statistically increased(P<0.05); Comparedwith the Al group, these values of EGF+Al group obviously return (P<0.05). Conclusion Thedepression of AMPA receptors phosphorylation mediated by PI3K/PKB signal transductionpathway may relate to the damage on hippocampal LTP by aluminum in rats.Chapter Ⅲ The role of MAPK/ERK signal transduction pathway of AMPA receptortrafficking in the damage on hippocampal LTP by aluminum in ratsObjective To explore the role MAPK/ERK signal transduction pathway of AMPA receptortrafficking in the damage on hippocampal LTP by aluminum in rats. Methods Animals andtreatments were same with chapterⅠsection2. Following electrophysiological recordings, ERKactivity of rat hippocampus was detected by ELISA. Results Compared with the control group,the ERK activity of Al group significantly decreased (P<0.05), but the value of EGF groupstatistically increased(P<0.05).; Compared with the Al group, the value of EGF+Al groupobviously return (P<0.05). Conclusion The MAPK/ERK signal transduction pathway may relateto the damage on hippocampal LTP by aluminum in rats, but the involvement of AMPA receptorsphosphorylation is not clear.Conclusions:Acute and subchronic aluminum exposure obviously and dose-dependentlysuppressed LTP in the rat hippocampal CA1region in vivo.The suppression on LTP induced by aluminum may be related to both trafficking and decreases in the expression of AMPA receptor subunit proteins.RAS→PI3K/PKB→GluR1S831和S845signal transduction pathway may relate tothe damage on hippocampal LTP by aluminum in rats.RAS→MAPK/ERK signal transduction pathway may relate to the damage onhippocampal LTP by aluminum in rats, but the involvement of AMPA receptorsphosphorylation is not clear.更多还原