Background The effect of chronic stress on cognitive functions has been one of the hot topic in neuroscience. But there has been much controversy over its mechanism. Such single stressor applied in the past could not ...Background The effect of chronic stress on cognitive functions has been one of the hot topic in neuroscience. But there has been much controversy over its mechanism. Such single stressor applied in the past could not simulate complicated living circumstances that people confronted with. The aim of this study was to investigate the effects of chronic multiple-stress on learning and memory as well as on the levels of calcium/calmodulin-dependent protein kinase Ⅱ（CaMKⅡ）, calmodulin （CAM） mRNA, and cAMP-response element binding protein （CREB） mRNA in the hippocampus of rats. Methods The rats were divided randomly into stressed and control groups. The stressed group was given chronic multiple-stress for 6 weeks to set up a chronic multiple-stressed model. The rats＇ performance of spatial learning and memory was tested using Morris Water Maze （MWM） and Y-maze. Meanwhile, the expressions of CAMKII, CAM mRNA and CREB mRNA of rats＇ hippocampus were detected by immunohistochemistry, Western blot and reverse transcription-polymerase chain reaction （RT-PCR）, respectively. In addition, the width of synaptic cleft and the thickness of post-synaptic densities （PSD） were observed in the hippocampal CA3 region of rats by electron microscopy. Results After exposure to chronic multiple-stress for 6 weeks, the ability of learning and memory of the stressed group was higher than that of the control group （P〈0.05, P〈0.01）. The width of synaptic cleft was smaller and the thickness of PSD was larger in the hippocampal CA3 region of the stressed group than in that of the control group （P〈0.01）. The CAMKII immunostaining of the stressed group was stronger than that of the control group in the stratum radiatum and oriens of the hippocampal CA1 and CA3, especially in the stratum oriens. Quantitative analysis indicated that the expression of CAMKII, CAM mRNA, and CREB mRNA in the hippocampus of the stressed group was higher than that of the control group （P〈0.05, P〈0.01）. Conclusions The 展开更多
钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)是一种在学习和记忆形成机制中具有重要作用的蛋白激酶,它存在于大多数组织中,但以神经元中表达量最高。大多数具有激酶活性的蛋白分子在组织中的表达量...钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)是一种在学习和记忆形成机制中具有重要作用的蛋白激酶,它存在于大多数组织中,但以神经元中表达量最高。大多数具有激酶活性的蛋白分子在组织中的表达量都相对较低,所以CaMKⅡ在神经系统中高度表达具有其特殊意义。该文将较为全面的对CaMKⅡ的分子结构与自身磷酸化特征、亚细胞空间定位及其在突触可塑性中的作用进行综述。展开更多
目的急性缺血缺氧可致心功能受损和心律失常,钙离子在其中起重要作用,慢性缺氧对心功能及心肌细胞内钙离子活动同样产生影响,但机制不同。该研究拟通过慢性缺氧动物模型,研究慢性缺氧对心肌细胞内钙调素(calmodulin,CaM)、钙/钙调素依...目的急性缺血缺氧可致心功能受损和心律失常,钙离子在其中起重要作用,慢性缺氧对心功能及心肌细胞内钙离子活动同样产生影响,但机制不同。该研究拟通过慢性缺氧动物模型,研究慢性缺氧对心肌细胞内钙调素(calmodulin,CaM)、钙/钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinase Ⅱ,CaMKⅡ)的表达及其对细胞内Ca2+活动的影响,深入了解慢性缺氧对心脏功能及电活动的影响机制。方法通过吸入低浓度含氧气体(FiO2:10%)建立慢性缺氧大鼠动物模型。在实验1周和3周时,应用RT-PCR,Western Blot方法分别检测对照组和慢性缺氧组动物心肌细胞内CaM和CaMKⅡγ、CaMKIIδmRNA和蛋白表达;分离并培养正常心肌细胞和缺氧3周细胞,应用激光共聚焦法分别检测两种心肌细胞内Ca2+活动,同时应用CaMKⅡ特异性抑制剂KN-62,观察CaMKII在慢性缺氧下对心肌细胞内Ca2+活动的影响。结果实验1周和3周时,慢性缺氧大鼠心肌细胞内CaM和CaMKIIγ、CaMKIIδ的mRNA和蛋白表达均较正常动物高(P<0.01);在缺氧1周和3周组动物间CaM和CaMKIIδ也存在差异(P<0.01),但CaMKⅡγ无差异(P>0.05)。激光共聚焦研究发现,慢性缺氧心肌细胞内Ca2+活动其钙波振幅虽和正常心肌细胞无差异(P>0.05),但钙波时程延长(P<0.01);应用KN-62后,慢性缺氧动物钙波振幅和时程改变较明显(P<0.01)。结论慢性缺氧可使大鼠心肌细胞内CaM和CaMKⅡ合成代偿性增加,保持大鼠心肌细胞内钙稳态,从而在一定时期内维持心功能稳定。但随缺氧时间延长,心功能可受损并可致心律失常。展开更多
目的:研究钙/钙调蛋白依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)和活化T细胞核因子(nuclear factor of activated T cells,NFAT)是否参与急性肾损伤(acute kidney injury,AKI)中肾小管上皮细胞(renal tu...目的:研究钙/钙调蛋白依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)和活化T细胞核因子(nuclear factor of activated T cells,NFAT)是否参与急性肾损伤(acute kidney injury,AKI)中肾小管上皮细胞(renal tubular epithelial cells,RTEC)凋亡并探讨其机制。方法:阿霉素(adriamycin,ADR)干预人近端肾小管上皮细胞HK-2建立RTEC凋亡模型,小干扰RNA(small interfering RNA,siRNA)沉默NFAT基因,流式细胞术测细胞凋亡率。ADR干预6~8周龄雌性BALB/c小鼠建立AKI模型,将小鼠分为3组:正常对照组、ADR组和ADR+CaMKⅡ抑制剂KN-93干预组,每组5只。酶联免疫吸附实验检测小鼠血清肌酐浓度。Western blot检测体内外Bax、Bcl-2、p-CaMKⅡ、CaMKⅡ及核NFAT的蛋白水平。结果:与正常对照组相比,ADR干预下,HK-2细胞凋亡率显著升高(P<0.01),小鼠血清肌酐和Bax蛋白表达显著升高,而Bcl-2蛋白表达显著下降(P<0.05)。ADR干预下,HK-2细胞和小鼠肾组织中CaMKⅡ活性(p-CaMKⅡ/t-CaMKⅡ)与核蛋白NFAT表达皆显著升高(P<0.01)。ADR干预的HK-2细胞和小鼠中抑制CaMKⅡ活性后,HK-2细胞凋亡率显著降低,小鼠血清肌酐和Bax蛋白表达显著回降,而Bcl-2蛋白表达显著回升,核蛋白NFAT表达显著回降(P<0.05)。此外,用钙调蛋白激活CaMKⅡ后HK-2细胞凋亡率显著升高(P<0.05);激活CaMKⅡ同时予siRNA沉默NFAT,HK-2细胞凋亡率显著降低(P<0.05)。结论:CaMKⅡ/NFAT通路激活可促进AKI小鼠肾小管上皮细胞凋亡。展开更多
基金supported by High School Science and Technology Fund Planning Project of Tianjin Municipality,China(No.20060206)the Scientific Research Fund of Tianjin Medical University,China(No.2011ky33)
基金This study was supported by a grant from the National Natural Science Foundation of China (No. 30270446).
文摘Background The effect of chronic stress on cognitive functions has been one of the hot topic in neuroscience. But there has been much controversy over its mechanism. Such single stressor applied in the past could not simulate complicated living circumstances that people confronted with. The aim of this study was to investigate the effects of chronic multiple-stress on learning and memory as well as on the levels of calcium/calmodulin-dependent protein kinase Ⅱ（CaMKⅡ）, calmodulin （CAM） mRNA, and cAMP-response element binding protein （CREB） mRNA in the hippocampus of rats. Methods The rats were divided randomly into stressed and control groups. The stressed group was given chronic multiple-stress for 6 weeks to set up a chronic multiple-stressed model. The rats＇ performance of spatial learning and memory was tested using Morris Water Maze （MWM） and Y-maze. Meanwhile, the expressions of CAMKII, CAM mRNA and CREB mRNA of rats＇ hippocampus were detected by immunohistochemistry, Western blot and reverse transcription-polymerase chain reaction （RT-PCR）, respectively. In addition, the width of synaptic cleft and the thickness of post-synaptic densities （PSD） were observed in the hippocampal CA3 region of rats by electron microscopy. Results After exposure to chronic multiple-stress for 6 weeks, the ability of learning and memory of the stressed group was higher than that of the control group （P〈0.05, P〈0.01）. The width of synaptic cleft was smaller and the thickness of PSD was larger in the hippocampal CA3 region of the stressed group than in that of the control group （P〈0.01）. The CAMKII immunostaining of the stressed group was stronger than that of the control group in the stratum radiatum and oriens of the hippocampal CA1 and CA3, especially in the stratum oriens. Quantitative analysis indicated that the expression of CAMKII, CAM mRNA, and CREB mRNA in the hippocampus of the stressed group was higher than that of the control group （P〈0.05, P〈0.01）. Conclusions The
文摘钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinaseⅡ,CaMKⅡ)是一种在学习和记忆形成机制中具有重要作用的蛋白激酶,它存在于大多数组织中,但以神经元中表达量最高。大多数具有激酶活性的蛋白分子在组织中的表达量都相对较低,所以CaMKⅡ在神经系统中高度表达具有其特殊意义。该文将较为全面的对CaMKⅡ的分子结构与自身磷酸化特征、亚细胞空间定位及其在突触可塑性中的作用进行综述。
文摘目的急性缺血缺氧可致心功能受损和心律失常,钙离子在其中起重要作用,慢性缺氧对心功能及心肌细胞内钙离子活动同样产生影响,但机制不同。该研究拟通过慢性缺氧动物模型,研究慢性缺氧对心肌细胞内钙调素(calmodulin,CaM)、钙/钙调素依赖性蛋白激酶Ⅱ(calcium/calmodulin-dependent protein kinase Ⅱ,CaMKⅡ)的表达及其对细胞内Ca2+活动的影响,深入了解慢性缺氧对心脏功能及电活动的影响机制。方法通过吸入低浓度含氧气体(FiO2:10%)建立慢性缺氧大鼠动物模型。在实验1周和3周时,应用RT-PCR,Western Blot方法分别检测对照组和慢性缺氧组动物心肌细胞内CaM和CaMKⅡγ、CaMKIIδmRNA和蛋白表达;分离并培养正常心肌细胞和缺氧3周细胞,应用激光共聚焦法分别检测两种心肌细胞内Ca2+活动,同时应用CaMKⅡ特异性抑制剂KN-62,观察CaMKII在慢性缺氧下对心肌细胞内Ca2+活动的影响。结果实验1周和3周时,慢性缺氧大鼠心肌细胞内CaM和CaMKIIγ、CaMKIIδ的mRNA和蛋白表达均较正常动物高(P<0.01);在缺氧1周和3周组动物间CaM和CaMKIIδ也存在差异(P<0.01),但CaMKⅡγ无差异(P>0.05)。激光共聚焦研究发现,慢性缺氧心肌细胞内Ca2+活动其钙波振幅虽和正常心肌细胞无差异(P>0.05),但钙波时程延长(P<0.01);应用KN-62后,慢性缺氧动物钙波振幅和时程改变较明显(P<0.01)。结论慢性缺氧可使大鼠心肌细胞内CaM和CaMKⅡ合成代偿性增加,保持大鼠心肌细胞内钙稳态,从而在一定时期内维持心功能稳定。但随缺氧时间延长,心功能可受损并可致心律失常。
