大鼠ASIC2a和ASIC3同聚体离子通道电生理学特性的研究

发布时间：2018-06-12 21:10

  本文选题：酸感受离子通道2a + 酸感受离子通道3　； 参考：《沈阳药科大学》2007年硕士论文

【摘要】： 酸感受离子通道(acid-sensing ion channels，，ASICs)是一类由胞外酸化所激活的阳离子通道，属于真皮钠离子通道家族。至今已经克隆出这个家族7个不同亚基：ASIC1a；ASIC1b；ASIC1b2；ASIC2a；ASIC2b；ASIC3和ASIC4。ASICs在体内分布广泛，功能复杂。其中ASIC2a和ASIC3因在酸味觉、触觉、疼痛等方面具有重要的生理学功能和病理学意义而逐渐成为研究热点。 本实验应用分子生物学技术，成功构建大鼠ASIC2a和ASIC3全长表达质粒。将编码ASIC2a和ASIC3亚基的cRNA分别注射到爪蟾卵母细胞中，使其表达并组成ASIC2a和ASIC3的同聚体离子通道，使用双电极电压钳技术记录H~+诱发电流，分析电流的药理学和门控动力学特征，观察Ca~(2+)、Na~+及K~+离子对H~+诱发电流的影响。研究发现：降低胞外液pH值可诱导出内向电流，pH值越小H~+诱发的电流幅度越大。ASIC2a的pH_(50)为5.12，ASIC3的pH_(50)为5.83。ASIC2a的内向电流具有稳态失活成分，ASIC3的内向电流具有快速和稳态失活两种成分。提高胞外Ca~(2+)浓度可降低H~+诱发的电流幅度。胞外Ca~(2+)对ASIC2a和ASIC3抑制作用的IC_(50)分别为11.98 mmol/L和9.16 mmol/L。ASIC2a和ASIC3除了对Na~+通透外，对K~+也具有一定程度的通透。 本实验以爪蟾卵母细胞为表达载体，成功建立了ASIC2a和ASIC3离子通道表达细胞模型，系统的观察了ASIC2a和ASIC3同聚体离子通道的电生理学特性及不同离子对其功能的影响。本研究结果不仅有利于进一步加深对ASICs生物学特性的了解，而且也为靶向ASICs类药物的研发提供了较为理想的筛选和评价技术平台。
[Abstract]:Acid-sensing ion channels are a kind of cationic channels activated by extracellular acidification and belong to the dermal sodium ion channel family. Up to now, seven different subunits of this family have been cloned: ASIC1b, ASIC1b2, ASIC2b2, ASIC2b, ASIC3 and ASIC4.ASICs, which are widely distributed and have complex functions in vivo. Among them, ASIC2a and ASIC3 have become the research focus because of their important physiological function and pathological significance in acid sense, tactile sense, pain and so on. In this study, the full length expression plasmids ASIC2a and ASIC3 were successfully constructed by molecular biology. The cRNA encoding ASIC2a and ASIC3 subunits were injected into Xenopus oocytes to express and form the homopolymer ion channels of ASIC2a and ASIC3 respectively. The H- induced currents were recorded by double electrode voltage clamp technique, and the pharmacological and gated characteristics of the currents were analyzed. The effects of Na ~ and K ~ + on H ~ -induced currents were observed. It was found that the lower the pH value of extracellular solution was, the greater the amplitude of inward current was. The pH of ASIC2a was 5.12 and the pH of ASIC3 was 5.83. The inward current of ASIC2a had two components: fast and steady-state inactivation. The increase of extracellular Caan2 concentration can reduce the amplitude of H- induced currents. The inhibitory effects of extracellular Caanzao 2 on ASIC2a and ASIC3 were 11.98 mmol / L and 9.16 mmol / L ASIC2a and ASIC3, respectively. The ASIC2a and ASIC3 ion channel expression cell models were successfully established using Xenopus oocytes as expression vector. The electrophysiological characteristics of ASIC2a and ASIC3 homopolymer ion channels and the effects of different ions on their function were systematically observed. The results of this study not only help to further understand the biological characteristics of ASICs, but also provide an ideal platform for screening and evaluation of targeted ASICs drugs.
【学位授予单位】：沈阳药科大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R33

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