电压门控钠离子通道与癫痫

电压门控钠离子通道(voltage-gated sodium channels,VGSCs)在动作电位产生和传导中至关重要.近年来研究发现,VGSCs与癫痫发病机制有着密切关系,许多癫痫综合征的发生已被证明是由VGSCs相关突变引起,且VGSCs的两种亚基(α和β)的相关基因发生突变均可以引起癫痫发作.其中与癫痫相关的α亚基主要有Nav1.1,Nav1.2,Nav1.3,Nav1.6,Nav1.7以及Na等几种亚型.本文就电压门控钠离子通道相关基因突变致癫痫的研究进展进行综述,旨在提高对癫痫的认识.     

电压-门控Na+通道基因突变与癫痫

电压-门控Na+通道和癫痫的关系十分密切，许多癫痫综合征的发生已被证明是由Na+通道基因突变引起，且编码α和/或β亚单位的基因发生突变均可以引起癫痫。基因突变后产生的异常Na+通道蛋白引起癫痫的发病机制仍不明确。基因和细胞治疗为治疗离子通道基因突变引起的癫痫提供了新的思路。     

背根神经节电压门控钠离子通道与神经性疼痛的研究进展

神经性疼痛属于慢性疼痛,以痛觉过敏为特征,表现为自发性持续或间歇性烧灼痛,同时对疼痛刺激的反应性增高.由于发病机制尚不清楚,一直以来是困扰医学界的难题.背根神经节(DRG)作为痛觉传入的第一级神经元在痛觉的外周机制中起着极为重要的作用,对背根神经节上离子通道的认识,对于阐明神经性疼痛的机制有重要意义.本文结合近年来对背根节上电压门控钠通道的研究进展,对其与神经性疼痛的关系加以综述,望有助于同行了解相关领域的最新研究动态.     

电压门控氯通道3（ClC-3）的生物学作用及其与疾病的关系

ClC-3属于电压门控氯通道家族,存在于细胞膜和细胞质,以及某些肿瘤细胞的细胞核内,高表达于中枢神经系统、肾脏和肠道。ClC-3参与离子转运、容积调节、免疫应答、细胞迁移、增殖、分化、凋亡等生理生物学活动,近年发现ClC-3与肿瘤、糖尿病等疾病的发生密切相关。     

电压门控离子通道功能与结构分子模型

离子通道是细胞膜上特殊跨膜蛋白构成的亲水孔道,越来越多的证据表明其与兴奋性、腺体分泌、机体运动、甚至学习和记忆行为等重要生理现象密切相关,由此该领域成为当今生命学科广为注目的前沿之一。本文将简要介绍离子通道的分类和功能,并侧重阐明通道压控原理及压控通道的跨膜拓扑结构和功能分子模型。     

遗传性癫痫大鼠海马内电压门控性钠离子通道四种亚型的表达及分布

目的探讨遗传性癫痫大鼠(Tremor rat,TRM)大脑海马中,电压门控性钠离子通道Ⅰ、Ⅱ、Ⅲ、Ⅳ亚型(Na_v1.1、Na_v1.2、Na_v1.3与Na_v1.6)的表达及分布。方法 Western blot检测TRM(n=7)和Wistar大鼠(n=7)海马中Na_v1.1、Na_v1.2、Na_v1.3与Na_v1.6的蛋白表达情况。免疫荧光法进一步分析TRM及Wistar大鼠海马CAI、CA3和DG区中这四种亚型的分布与定位。结果相较于正常大鼠,TRM海马中Na_v1.1、Na_v1.2、Na_v1.3与Na_v1.6蛋白表达均明显上调(P0.01)。此外,这四种VGSC亚型在TRM海马CAI,CA3区神经元及DG区颗粒细胞中分布广泛,且主要定位在细胞膜上。结论 Na_v1.1、Na_v1.2、Na_v1.3与Na_v1.6在TRM大鼠海马中出现显著高表达,可能与遗传性癫痫发生机制有关。     

表皮生长因子促进电压门控钠通道Nav1.5表达及人乳腺癌细胞的侵袭

目的 探讨表皮生长因子(EGF)是否调节乳腺癌MDA-MB-231细胞电压门控钠通道(VGSC)Nav1.5亚型基因的表达及其可能的信号分子传导途径.方法 用Matrigel侵袭、免疫荧光定位、实时荧光定量RT.PCR(RFQ-PCR)和Western blot等方法,分别检测或探讨EGFR和Nav1.5蛋白在细胞中的表达和定位、EGF和Nav1.5对细胞侵袭的作用、EGF对Nav1.5 mRNA和蛋白水平的影响以及P13K在EGF增加侵袭中的作用.结果 MDA-MB-231细胞高表达EGF受体和Nav1.5蛋白,EGF增加细胞的侵袭达51.0%±2.6%,VGSC抑制剂Tetrodotoxin(TTX)10 μmol/L阻滞EGF诱导的细胞侵袭(P＜0.05);EGF增加Nav1.5 mRNA水平为(128±4)倍(P＜0.05),Nav1.5蛋白水平有39%±4%上升(P＜0.05).P13K抑制剂Wortmannin抑制EGF诱导的Nav1.5 mRNA和蛋白水平的增加,亦抑制EGF诱导的细胞侵袭.结论 EGF上调乳腺癌MDA-MB-231细胞VGSC Nav1.5亚型mRNA和蛋白的表达,促使乳腺癌细胞的侵袭,P13K参与EGF诱导的Nav1.5的表达和细胞的侵袭.     

电压门控氯通道C1C蛋白突变体及相关疾病研究进展

CIC是一组介导氯离子跨膜转运的蛋白质,参与细胞多种生理及病理过程.基因突变形成的异常C1C蛋白影响离子通道门控特性,从而扰乱氯离子的正常跨膜转运,可导致先天性肌强直、先天性癫痫、Bartter综合征、Dent's病、视网膜退化病及骨硬化病等多种疾病.     

大鼠肺动脉平滑肌细胞的分离及电压门控性钾电流的记录方法

目的介绍一种大鼠肺动脉平滑肌细胞(PASMCs)的急性分离方法并观察电压门控性钾电流电生理特性。方法应用胶原酶和木瓜蛋白酶联合消化法获得大鼠PASMCs,利用全细胞膜片钳技术记录PASMCs膜上的电压门控性钾通道(Kv)电流。结果在相差显微镜下观察大鼠PASMCs呈舒展梭形,边界清晰,有完整的细胞膜,胞浆均匀,数量多,活性好。结论用酶急性分离的大鼠PASMCs,容易进行全细胞膜片钳记录,方法简单、稳定、可靠。     

电压-门控Na~+通道在神经系统中的分布及与胶质瘤的关系

电压-门控Na+通道是神经元产生兴奋性所需的最基本的离子通道,在神经元静息电位的维持、动作电位的产生及传导等过程中发挥着重要的作用。目前已知至少有9种亚型的电压-门控Na+通道在神经系统中表达,它们不仅在维持神经元正常电生理活动中扮演着重要的角色,而且与神经系统许多疾患,如胶质瘤的发生发展密切相关。     

容积调控性氯离子通道与肿瘤

容积调控性氯通道在细胞的容积调节、增殖及凋亡等生理过程中发挥重要作用，其分子结构尚未确定。近年研究发现容积调控性氯通道与肿瘤细胞的增殖、侵袭、迁移、凋亡及多药耐药性等恶性生物学行为有关。随着研究深入，容积调控性氯通道将成为抗肿瘤治疗的新靶点。     

Responsiveness of voltage-gated calcium channels in SH-SY5Y human neuroblastoma cells on micropillar substrates

In this study, poly-L-lactic acid micropillar substrates were fabricated to evaluate the influence of topographic substrates on cell morphological and functional characteristics, such as spreading area, voltage-gated calcium channels (VGCCs) and membrane potential. The proliferation, spreading area, perimeter and circularity of SH-SY5Y cells interfaced with different substrates were first investigated. In addition, the cytoskeleton and focal adhesion of a cell as important manifestations of cell morphology were analyzed by immunofluorescence. VGCC responsiveness was evaluated by measuring the dynamic changes in intracellular Ca²⁺ evoked by 50 mM extracellular K⁺. To determine study whether the differences in VGCC responsiveness were caused by the differences in VGCC gene expression, the expression of N/L- type VGCCs was determined by qPCR and fluorescence staining. Notably, improved measurement of the membrane potential with potentiometric fluorescent dye TMRM was applied to determine the membrane potential of SH-SY5Y cells. Results indicated that the SH-SY5Y cells were deformed significantly to adapt to the substrates; however, no distinct effect on the proliferative ability of SH-SY5Y cells was observed. The micropillar substrates markedly influenced VGCC responsiveness, which correlated strongly with cell spreading but not with VGCC expression. The resting membrane potential of SH-SY5Y cells cultured on different substrates also changed, but no effect on responsiveness of VGCC was observed. These results suggest that the effect of the micropillar substrates on cell VGCC responsiveness may be attributed to changes in the functionality of the ion channel itself. Thus, topographic substrates can be used to engineer cell functionality in cell-based drug screening.     

The modulation of voltage-gated potassium channels by anisotonicity in trigeminal ganglion neurons

Voltage-gated potassium channels (VGPCs) play an important role in many physiological functions by controlling the electrical properties and excitability of cells. Changes in tonicity in the peripheral nervous system can activate nociceptors and produce pain. Here, using whole cell patch clamp techniques, we explore how hypo- and hypertonicity modulate VGPCs in cultured rat and mouse trigeminal ganglion (TG) neurons. We found that hypo- and hypertonicity had different effects on slow-inactivating K+ current (IK) and fast-inactivating K+ current (IA): hypotonicity increased IK but had no effect on IA while hypertonicity depressed both IK and IA. The increase of IK by hypotonicity was mimicked by transient receptor potential vanilloid 4 (TRPV4) receptor activator 4alpha-phorbol-12,13-didecanoate (4alpha-PDD) but hypotonicity did not exhibit increase in TRPV4-/- mice TG neurons, suggesting that TRPV4 receptor was involved in hypotonicity-induced response. We also found that inactivation of PKC selectively reversed the increase of IK by hypotonicity, whereas antagonism of G-protein selectively rescued the inhibitions of IK and IA by hypertonicity, indicating that different intracellular signaling pathways were required for the modulation by hypo- and hypertonicity. In summary, changes in osmolality have various effects on IK and IA and different receptors and second messenger systems are selective for the modulation of VGPCs induced by hypo- versus hypertonicity.     

CaV 2.3 电压门控性钙通道与癫痫

癫痫是神经系统疾病中较为常见的疾病之一,由大量神经元反复发作的异常放电[1]而引起的中枢神经系统短暂性功能失常为特征.癫痫的发病机制非常复杂,包括Ca2+内流引发的细胞毒性;苔藓纤维芽生假说;谷氨酸和γ-氨基丁酸及其受体结构和功能异常;氧化应激损伤等.     

Developmental exposure to lead causes inherent changes on voltage-gated sodium channels in rat hippocampal CA1 neurons

In this study, the effects of chronic lead (Pb(2+)) exposure, during day 0 of gestation (E0) to postnatal day 15 (P15), on voltage-gated sodium channel currents (I(Na)) were investigated in CA1 field of the hippocampus (CA1) neurons using the conventional whole-cell patch-clamp technique on rat hippocampal slices. We found that developmental lead exposure increased the activation threshold and the voltage at which the maximum I(Na) current was evoked, caused positive shifts of I(Na) steady-state activation curve, and enlarged I(Na) tail-currents; Pb(2+) delayed the activation of I(Na) in a voltage-dependent manner, prolonged the time course of the fast inactivation of sodium channels; Pb(2+) induced a right shift of the steady-state inactivation curve, accelerated the activity-dependent attenuation of I(Na), but made no significant effects on the time course of the recovery of I(Na) from inactivation and the fraction of inactivated channels. In addition, the co-treatment with alpha-tocopherol (VE), an effective antioxidant and free radical scavenger, completely prevented the aforementioned changes on I(Na). The alterations on I(Na) properties induced by developmental lead exposure were partly different from that in previous acute experiments under the conditions closer to physiological situation, and the process was considered related to the participating of lead in lipid peroxidation reaction, which has been reported to change the conformation and biophysical functions of membrane proteins.     

大气压冷等离子体对肿瘤细胞增殖和凋亡的影响及其机制

目的:探讨大气压冷等离子体（CAP）对人肿瘤细胞增殖和凋亡的影响。方法:将处于对数生长期的人神经胶质瘤细胞（U87）和宫颈癌细胞（Hela）接种于培养板或培养皿中,待细胞贴壁生长后,将其随机分为正常对照（control）组、氦气（He）组和CAP不同时间处理组,细胞在接受不同时间CAP处理后,采用CCK-8方法检测细胞活力,流式细胞仪检测细胞凋亡情况,蛋白印迹法检测凋亡相关蛋白caspase3和氧化应激相关蛋白Nrf2的表达水平。结果:He处理对U87和Hela细胞的增殖能力和自发凋亡无明显影响,CAP处理后两种肿瘤细胞的细胞活力均显著降低,凋亡水平明显上升,caspase3蛋白和Nrf2蛋白的表达显著增加,CAP处理时间越长,效应越明显。结论:本实验条件下的CAP处理可抑制人肿瘤细胞的增殖,并诱导其凋亡,其机制可能与CAP导致的氧化应激有关。     

H2O2对大鼠肺动脉平滑肌细胞Kv通道的作用

 目的:观察H₂O₂在常氧时对大鼠肺动脉平滑肌细胞（PASMCs）的Kv的影响, 探讨H₂O₂对肺动脉平滑肌细胞的Kv通道的作用。 方法:用酶解法急性分离单个PASMCs，以全细胞膜片钳技术记录PASMCs膜上的电压依赖性钾通道 (voltage-gated potassium channel, Kv) 电流。 结果:常氧下 H₂O₂可显著增加Kv电流，电流-电压关系曲线左上移；而且Kv电流呈浓度依赖性增加。 结论:常氧下H₂O₂ 可使Kv通道开放。     

钙激活氯通道与哮喘黏液过度分泌及气道炎症的关系

哮喘的一个重要特征是杯状细胞增生和黏液过度分泌,大量黏液难以清除引起小气道阻塞并导致气道高反应性,急性哮喘死亡患者尸检显示大小气道均有杯状细胞增生和黏液过度分泌,这种黏液过度分泌导致的气道阻塞是重症哮喘主要死因之一,有研究证实黏液过度分泌是第1秒用力呼气容积(FEV1)下降加速的独立危险因素[1].