The localization of ion channels on myelinated axon is closely related with the saltatory conduction of action potential (AP). Abnormal changes in these channels contribute to multiple mental diseases. The development...The localization of ion channels on myelinated axon is closely related with the saltatory conduction of action potential (AP). Abnormal changes in these channels contribute to multiple mental diseases. The development of cryo-Electron Tomography (cryo-ET) has provided a promising prospect for peering into ion channels in their native environment at high resolution. Previous achievements are reviewed here on cryo-ET. Accordingly, a cryo-ET workflow is designed for understanding ion channels localization in myelinated axon, especially nodes of Ranvier, which are significant for the saltatory conduction involved in the propagation of high-speed AP. The workflow is divided into six parts: the preparation of neural cultures with myelin, antibodies and immunofluorescence staining, frozen-hydrated sample preparation, cryo-ET imaging, cryo-correlative light and electron microscopy (cryo-CLEM) imaging, three-dimensional (3D) reconstruction and refinement. The purpose is to conceive a possible solution for the problems related to ion channel compounds including localization, conformation dynamics, accessory structures of ion channel and transient regulatory factors, and thus provide insights into treating neurological diseases caused by abnormal ion channels activity.展开更多
Objective: To study the effect of KATp channel opener and its possible mechanism on the sinoatrial node cells of neonatal rats which were cultured under simulated ischemia-reperfusion. Methods: Freshly isolated sinoat...Objective: To study the effect of KATp channel opener and its possible mechanism on the sinoatrial node cells of neonatal rats which were cultured under simulated ischemia-reperfusion. Methods: Freshly isolated sinoatrial node (SAN) cells of neonatal rats were purified and cultured for 2 d, and then they were randomly divided into the control, simulated ischemia-reperfusion group (I/R group) , group intervened with KATp channel opener pinacidil (P + I/R group), KATP Channel blocking agent 5-HD (5-HD + I/R group) , and group with the 2 agents at same time (5-HD + P + I/R group) . The survival rate of cells was measured by flow cytometry and the content of intracellular calcium in the cells of each group was detected with laser confocal microscopy. Results: ① The survival rate of SAN cells in I/R group [ (51. 79±6. 28)% ] was remarkably significantly lower than in control [ (95. 08±10. 48)% ] (P < 0.001), and very significantly lower than in P + I/R group [ (63. 77±5. 35) % ] (P<0.01), however, those of 5-HD + P + I/R group [(52. 88±6. 25)% ] and 5-HD+I/R group [ (53. 16±5. 35)% ] was significantly lower compared with that in P + I/R group (P <0. 01) ; ② When the average fluorescence intensity of sinoatrial node cells in the control was regarded as 100% , the relative fluorescence intensities of each group were: ( 374±52) % in I/R group, significantly higher than that of control (P <0. 01) ; ( 162±20)% in P + I/R group, declining significantly than that of I/R group (P<0.01); (385?6)% in 5-HD+ P + I/R group and (379±44)% in 5-HD + I/R group, increasing significantly than that of I/R group (P<0.01). Conclusion: ① Simulated ischemia-reperfusion can significantly reduce the survival rate of SAN cells, and can also lead to the overload of intracellular calcium in them.② KATp channel opener, pinacidil, exerts protective effect on the cells under simulated ischemia-reperfusion, which may be associated with the decrease of intracellular calcium loading in them.展开更多
含大规模分布式光伏与柔性负荷的新型配电网运行方式愈发复杂,配电网同步测量装置(synchrophasor measurement unit for distribution network,D-PMU)优化配置可为其协同调度控制提供有效的同步测量数据。然而,在配电网发生N-1故障并进...含大规模分布式光伏与柔性负荷的新型配电网运行方式愈发复杂,配电网同步测量装置(synchrophasor measurement unit for distribution network,D-PMU)优化配置可为其协同调度控制提供有效的同步测量数据。然而,在配电网发生N-1故障并进行重构后,原有的配置方案难以满足调度控制需求。因此,提出一种考虑N-1故障重构下的D-PMU优化配置方法。首先,提出计及配电网重构的节点电压损失和网络拓扑结构的节点脆弱程度指标,划分节点权重;为保证故障重构后配电网可观,提出考虑N-1故障重构的D-PMU优化配置模型,基于配电网重构获取了网络拓扑结构,建立N-1故障重构下的可观测约束,并考虑D-PMU通道数量有限以及数据监控与采集系统(supervisory control and data acquisition,SCADA)和高级量测系统(advanced measurement infrastructure,AMI)量测信息对所提模型的影响;建立D-PMU统一优化配置模型,充分考虑经济性、正常情况下的全网可观、零注入节点、N-1故障重构可观、D-PMU通道的限制和已存在的传统量测;进一步,利用IEEE 33和IEEE 69节点系统验证该方法的可行性和有效性。展开更多
Studies have shown that a combined application of several ion channel inhibitors immediately after central nervous system injury can inhibit secondary degeneration. However, for clinical use, it is necessary to determ...Studies have shown that a combined application of several ion channel inhibitors immediately after central nervous system injury can inhibit secondary degeneration. However, for clinical use, it is necessary to determine how long after injury the combined treatment of several ion channel inhibitors can be delayed and efficacy maintained. In this study, we delivered Ca^2＋ entry-inhibiting P2X7 receptor antagonist oxidized-ATP and AMPA receptor antagonist YM872 to the optic nerve injury site via an iPRECIO-@ pump immediately, 6 hours, 24 hours and 7 days after partial optic nerve transection surgery. In addition, all of the ion channel inhibitor treated rats were administered with calcium channel antagonist lomerizine hydrochloride. It is important to note that as a result of implantation of the particular pumps required for programmable delivery of therapeutics directly to the injury site, seromas occurred in a significant proportion of animals, indicating infection around the pumps in these animals. Improvements in visual function were observed only when treatment was delayed by 6 hours; phosphorylated Tau was reduced when treatment was delayed by 24 hours or 7 days. Improvements in structure of node/paranode of Ranvier and reductions in oxidative stress indicators were also only observed when treatment was delayed for 6 hours, 24 hours, or 7 days. Benefits of ion channel inhibitors were only observed with time-delayed treatment, suggesting that delayed therapy of Ca^2＋ ion channel inhibitors produces better neuroprotective effects on secondary degeneration, at least in the presence of seromas.展开更多
文摘The localization of ion channels on myelinated axon is closely related with the saltatory conduction of action potential (AP). Abnormal changes in these channels contribute to multiple mental diseases. The development of cryo-Electron Tomography (cryo-ET) has provided a promising prospect for peering into ion channels in their native environment at high resolution. Previous achievements are reviewed here on cryo-ET. Accordingly, a cryo-ET workflow is designed for understanding ion channels localization in myelinated axon, especially nodes of Ranvier, which are significant for the saltatory conduction involved in the propagation of high-speed AP. The workflow is divided into six parts: the preparation of neural cultures with myelin, antibodies and immunofluorescence staining, frozen-hydrated sample preparation, cryo-ET imaging, cryo-correlative light and electron microscopy (cryo-CLEM) imaging, three-dimensional (3D) reconstruction and refinement. The purpose is to conceive a possible solution for the problems related to ion channel compounds including localization, conformation dynamics, accessory structures of ion channel and transient regulatory factors, and thus provide insights into treating neurological diseases caused by abnormal ion channels activity.
基金Supported by National Natural Science Foundation of China (No. 30070314)
文摘Objective: To study the effect of KATp channel opener and its possible mechanism on the sinoatrial node cells of neonatal rats which were cultured under simulated ischemia-reperfusion. Methods: Freshly isolated sinoatrial node (SAN) cells of neonatal rats were purified and cultured for 2 d, and then they were randomly divided into the control, simulated ischemia-reperfusion group (I/R group) , group intervened with KATp channel opener pinacidil (P + I/R group), KATP Channel blocking agent 5-HD (5-HD + I/R group) , and group with the 2 agents at same time (5-HD + P + I/R group) . The survival rate of cells was measured by flow cytometry and the content of intracellular calcium in the cells of each group was detected with laser confocal microscopy. Results: ① The survival rate of SAN cells in I/R group [ (51. 79±6. 28)% ] was remarkably significantly lower than in control [ (95. 08±10. 48)% ] (P < 0.001), and very significantly lower than in P + I/R group [ (63. 77±5. 35) % ] (P<0.01), however, those of 5-HD + P + I/R group [(52. 88±6. 25)% ] and 5-HD+I/R group [ (53. 16±5. 35)% ] was significantly lower compared with that in P + I/R group (P <0. 01) ; ② When the average fluorescence intensity of sinoatrial node cells in the control was regarded as 100% , the relative fluorescence intensities of each group were: ( 374±52) % in I/R group, significantly higher than that of control (P <0. 01) ; ( 162±20)% in P + I/R group, declining significantly than that of I/R group (P<0.01); (385?6)% in 5-HD+ P + I/R group and (379±44)% in 5-HD + I/R group, increasing significantly than that of I/R group (P<0.01). Conclusion: ① Simulated ischemia-reperfusion can significantly reduce the survival rate of SAN cells, and can also lead to the overload of intracellular calcium in them.② KATp channel opener, pinacidil, exerts protective effect on the cells under simulated ischemia-reperfusion, which may be associated with the decrease of intracellular calcium loading in them.
文摘含大规模分布式光伏与柔性负荷的新型配电网运行方式愈发复杂,配电网同步测量装置(synchrophasor measurement unit for distribution network,D-PMU)优化配置可为其协同调度控制提供有效的同步测量数据。然而,在配电网发生N-1故障并进行重构后,原有的配置方案难以满足调度控制需求。因此,提出一种考虑N-1故障重构下的D-PMU优化配置方法。首先,提出计及配电网重构的节点电压损失和网络拓扑结构的节点脆弱程度指标,划分节点权重;为保证故障重构后配电网可观,提出考虑N-1故障重构的D-PMU优化配置模型,基于配电网重构获取了网络拓扑结构,建立N-1故障重构下的可观测约束,并考虑D-PMU通道数量有限以及数据监控与采集系统(supervisory control and data acquisition,SCADA)和高级量测系统(advanced measurement infrastructure,AMI)量测信息对所提模型的影响;建立D-PMU统一优化配置模型,充分考虑经济性、正常情况下的全网可观、零注入节点、N-1故障重构可观、D-PMU通道的限制和已存在的传统量测;进一步,利用IEEE 33和IEEE 69节点系统验证该方法的可行性和有效性。
基金financial support from the National Health and Medical Research Council(NHMRC),Australia(APP1061791)an NHMRC Career Development Fellowship(APP1087114)
文摘Studies have shown that a combined application of several ion channel inhibitors immediately after central nervous system injury can inhibit secondary degeneration. However, for clinical use, it is necessary to determine how long after injury the combined treatment of several ion channel inhibitors can be delayed and efficacy maintained. In this study, we delivered Ca^2＋ entry-inhibiting P2X7 receptor antagonist oxidized-ATP and AMPA receptor antagonist YM872 to the optic nerve injury site via an iPRECIO-@ pump immediately, 6 hours, 24 hours and 7 days after partial optic nerve transection surgery. In addition, all of the ion channel inhibitor treated rats were administered with calcium channel antagonist lomerizine hydrochloride. It is important to note that as a result of implantation of the particular pumps required for programmable delivery of therapeutics directly to the injury site, seromas occurred in a significant proportion of animals, indicating infection around the pumps in these animals. Improvements in visual function were observed only when treatment was delayed by 6 hours; phosphorylated Tau was reduced when treatment was delayed by 24 hours or 7 days. Improvements in structure of node/paranode of Ranvier and reductions in oxidative stress indicators were also only observed when treatment was delayed for 6 hours, 24 hours, or 7 days. Benefits of ion channel inhibitors were only observed with time-delayed treatment, suggesting that delayed therapy of Ca^2＋ ion channel inhibitors produces better neuroprotective effects on secondary degeneration, at least in the presence of seromas.
