缺氧对培养的猪肺内皮细胞胞浆游离钙的影响

本文应用荧光探针Ｆｕｒａ－１／ＡＭ测定胞浆游离钙浓度（［Ｃａ＾２＋］ｉ）技术，观察培养的猪肺动脉内皮细胞［Ｃａ＾２＋］ｉ在缺氧时变化。实验发现：向细胞悬液中充氮气造成缺氧时，肺动脉内皮细胞［Ｃａ＾２＋］ｉ升高８１±２１％（Ｐ＜０．０５，ｎ＝８）。结果提示肺动脉内皮细胞钙信使系统可能参与缺氧所致血管反应。     

人工细胞抗高血压因子对人脐静脉VSMC胞浆及核内Ca^2＋水平的影响

采实验用Ｆｌｕｏ－３／ＡＭ染色在激光扫描共聚焦显微镜下观察了红细胞抗高血压因子（ａｎｔｉｈｙｐｅｒｔｅｎｓｉｖｅ ｆａｃｔｏｒ,ＡＨＦ）对人脐静脉ＶＳＭＣ胞浆（〗Ｃａ＾２＋〖）及核内（〖Ｃａ＾２＋〗ｎ）游离钙离了瓣影响。结果表明：ＡＨＦ（１０＾－４ｇ／ｍＬ）明显抑制Ｂａｙ ｋ８６４４（１０＾－６ｍｏｌ／Ｌ）ＫＣｌ（６０ｍｍｏｌ／Ｌ）,ＡｎｇⅡ（１０＾－６ｍｏｌ／Ｌ）及ＩＰ３（１０＾－５ｍｏｌ／Ｌ）     

低氧对肺动脉内皮细胞分泌一氧化氮的影响

以内皮细胞合成了一氧化氮（ＥＤＮＯ）的代谢产物ＮＯ＾－２为指标，观察了低氧条件下猪肺动脉内皮细胞合成分泌ＥＤＮＯ及细胞内Ｃａ＾２＋浓度的变化，发现低氧时内皮细胞合成分泌的ＥＤＮＯ明显增加，但随着低氧时间延长，增加的幅度减小，内皮细胞的（Ｃａ２＋）ｉ显著增加。而低氧培养时间的长短对（Ｃａ＾２＋）ｉ没有明显的影响。结果表明，低氧条件下内皮细胞（Ｃａ＾２＋）ｉ的增加是ＥＤＮＯ合成分泌增加的重要原因之一。     

多聚C1q诱导免疫细胞的Ca^2＋动员

多聚Ｃｌｑ与人Ｔ细胞系Ｊｕｒｋａｔ、Ｂ细胞系Ｒａｊｉ和ＭΦ系Ｕ９３７细胞表面ＣｌｑＲ相互作用，诱导＾４５Ｃａ＾２＋跨膜快速内流，刺激［Ｃａ＾２＋］ｉ迅速增高，前者可为质膜Ｃａ＾２＋通道阻滞剂Ｖｅｒａｐａｍｉｌ所阻断，后者能被胞外Ｃａ＾２＋络合剂ＥＧＴＡ部分抑制，被蛋白酪氨酸激酶（ＰＴＫ）抑制剂Ｇｅｎｉｓｔｅｉｎ完全消除。资料表明，Ｃｌｑ／ＣｌｑＲ系统介导的信号转导机制涉及内Ｃａ＾２＋和外Ｃａ＾２＋     

P物质对人脐静脉张力及内皮细胞Ca2+的调控及其机制

目的：观察P物质（SP）对人脐静脉张力的调节及其对体外培养人脐静脉内皮细胞（HUVEC）膜上Ca^2 通道及胞浆内游离Ca^2 浓度[(Ca^2 )i]的调控作用。方法：应用常规生理记录仪，记录SP对人脐静脉张力的影响，用共聚焦激光扫描显微术和膜片钳单通道记录技术对体外培养HUVEC胞浆内（Ca^2 )i、膜上Ca^2 通道开放情况进行观察。结果：SP具有内皮依赖性舒张人脐静脉的作用，促使体外培养HUVEC胞膜上Ca^2 通道开放和胞浆内（Ca^2 ）i明显升高。结论：SP对人脐静脉张力的舒张作用可能通过HUVEC胞浆内储存的（Ca^2 ）i释放和膜上Ca^2 通道开放，达到其调节效应。     

山莨菪碱对蛛网膜下腔出血后基底动脉产生EDRF的作用及抗…

用山莨菪碱（６５４－２）防治蛛网膜下腔出血（ＳＡＨ）后脑血管痉挛，观察６５４－２对基底动脉中ＥＤＲＦ，ＭＤＡ，ＳＯＤ，ｃＧＭＰ，Ｃａ＾２＋，Ｎａ＾２＋的影响。结果表明，应用６５４－２后降低了基底动脉中ＭＤＡ产生及Ｃａ＾２＋Ｎａ＾＋的含量，与ＳＡＨ组比，ＥＤＲＦ释放增加，ＳＯＤ活性及ｃＧＭＰ水平提高，基底动脉内皮细胞受到保护，基底动脉收缩幅度减小。提示，６５４－２可通过保护内皮细胞，减轻氧自由基损伤     

H^＋——Ca^2＋交换在心肌细胞缺氧复氧过程中所致Ca^2＋超负荷…

多数资料表明，在心肌细胞发生氧反常和ｐＨ反常后，Ｈ＾＋－Ｎａ＾＋，Ｎａ＾＋－Ｃａ＾２＋交换加强是细胞内Ｃａ＾２＋超载的重要机制，我们的研究表明，造成细胞Ｃａ＾２＋超载的原因，除Ｈ＾＋－Ｎａ＾＋，Ｎａ＾＋－Ｃａ＾２＋交换外，尚有Ｈ－Ｃａ＾２＋交换参加，本实验证实，在细胞缺氧１０，２０，３０和４０ｍｉｎ时，经Ｈ＾＋－Ｃａ＾２＋交换进入细胞的Ｃａ＾２＋量占同一时点细胞摄Ｃａ＾２＋总量的比率分别为（％），     

下丘脑[Ca^2＋]i,cAMP在家兔EGTA性发热机制中的作用

用６０只新西兰兔分两部分进行实验。（１）用１２只制备下丘脑细胞悬液，在离体条件下，应用Ｆｕｒａ－２荧光指示剂测定细胞内Ｃａ＾２＋浓度（Ｃａ＾２＋］ｉ）。结果表明，用ＥＧＴＡ络合神经细胞外Ｃａ＾２＋而降低细胞外Ｃａ＾２＋浓度时，下丘脑神经细胞（［Ｃａ＾２＋］ｉ）明显降低（Ｐ＞０．０１）；相反，增加细胞外Ｃａ＾２＋浓度，则［Ｃａ＾２＋］ｉ明显增高（Ｐ＞０．０１）。（２）用４８只家兔分４组，分别向侧脑室     

镁对大鼠缺氧再给氧心肌细胞内游离钙的影响

目的和方法：用ＡＣＡＳ５７０粘附式细胞仪，以荧光素染色法观察镁（Ｍｇ２＋）对体外培养乳鼠心肌细胞内游离钙（Ｃａ２＋）的影响及对缺氧再给氧时细胞内Ｃａ２＋作用。结果：细胞外Ｍｇ２＋降至０３ｍｍｏｌ·Ｌ－１，细胞内Ｃａ２＋荧光强度上升速度加快，达到稳定所需时间延长，出现Ｃａ２＋振荡曲线。增加Ｍｇ２＋浓度可使细胞内Ｃａ２＋降低。Ｍｇ２＋还可以显著减少缺氧再给氧时细胞内Ｃａ２＋，Ｐ＜００１。结论：细胞外低Ｍｇ２＋可导致细胞内Ｃａ２＋增加，Ｍｇ２＋有维持正常心肌细胞内Ｃａ２＋稳定性及拮抗缺氧再给氧时细胞内Ｃａ２＋超载作用     

极低频弱磁场对PC-12瘤细胞胞内游离钙离子浓度的影响

采用极低频弱磁对鼠嗜铬细胞瘤ＰＣ－１２株系细胞进行照射,利用显微荧光技术动态监测胞内游离钙离子浓度（［Ｃａ＾２＋］ｉ）的变化,实验结果表明：５０Ｈｚ,１００μＴ的正弦磁场照射引起［Ｃａ＾２＋］ｉ明显升高;而在同等强度的静磁场和２０００Ｈｚ正弦磁场照射下,［Ｃａ＾２＋］ｉ基本维持不变,进一步的实验说明［Ｃａ＾２＋］ｉ的升高部分源于细胞外Ｃａ＾２＋的跨膜内流,部分源于胞内钙库的释放。证实了一定强度下特     

淋巴细胞膜钾通道及其功能

离子通道在淋巴细胞活化过程中发挥重要作用.钾通道是淋巴细胞膜上的一类重要离子通道,分为2类电压门控钾通道(Kv)和钙激活的钾通道(KCa).Kv有3个亚型n,n'和l型.KCa可分为2类小电导KCa和中电导KCa°Kv是维持细胞静息膜电位的主要承担者.Kv和KCa对Ca2+信号具有重要的调节作用,从而分别在细胞活化的启动和维持阶段发挥主要作用.Kv通过和蛋白激酶的偶联参与了胞内激活信号转导过程.另外,Kv和氯通道共同作用调节细胞容积.对钾通道的深入研究将有助于新型免疫调节剂的研制.     

伤口巨噬细胞离子通道活动的实验研究

目的：研究伤口巨噬细胞离子通道活动的特点。方法：采用cell-attached膜片离子单通道记录方法。结果：伤口巨噬细胞膜上可记录到离子通道自发开放，这些自发性开放的通道包括以钾离子为载体的阳离子通道与以氯离子为载体的阴离子通道。文中对伤口巨噬细胞离子通道的生理功能进行了初步探讨。     

Ion channels and membrane rafts in apoptosis

Ion channels have been demonstrated to be a central element in the induction and the execution of apoptosis. In particular, mitochondrial ion channels, including not only the permeability transition pore but also a mitochondrial, ATP-sensitive (mK_ATP) channel as well as a mitochondrial calcium-activated potassium channel are involved critically in apoptotic changes in mitochondria. Ion channels in the cell membrane that are altered by induction of apoptosis include potassium, chloride and calcium channels. The Kv1.3 potassium channel belongs to the best-characterized ion channels involved in apoptosis and a genetic model of cells deficient for Kv1.3 has indicated a critical role for Kv1.3, at least in some forms of apoptosis. The mechanisms regulating ion channels during apoptosis are, however, still poorly defined. Recent studies have suggested a function for distinct membrane domains, termed rafts, in the cell membrane for the regulation of ion channels during apoptosis. Small sphingolipid- and cholesterol-enriched membrane domains are modified by many apoptotic stimuli to form large ceramide-enriched membrane platforms. These platforms serve to cluster receptor molecules, to re-organize intracellular signalling molecules including ion channels, to bring ion channels into close contact with their regulators and/or to separate proteins from a specific ion channel. Finally, the lipid composition of the cell membrane might be involved directly in ion channel regulation.     

儿童失神癫痫易感基因的研究

尽管近年来发现有少数非离子通道编码基因参与人类特发性癫痫（idiopathic eplepsies，IE），但更多的遗传学研究证实，离子通道在IE的遗传病理机制中起核心作用。离子通道基因突变是一些罕见类型的单基因遗传IE的常见病因，被称为通道病。但离子通道基因突变仅能解释IE的少数家系或散发病例，更大的难题来自于对复杂遗传IE的研究，它们未知的遗传模式、表型异质性和综合征亚型间不确定的遗传背景重叠限制了遗传图谱的绘制。失神癫痫是常见的IE亚型，呈复杂遗传方式。现共发现有11个基因与失神癫痫有关联，其中有4种编码神经元钙通道亚单位。因此钙通道基因是失神癫痫的重要候选基因。失神癫痫钙通道基因的遗传学研究可能是复杂遗传IE病因研究的最佳切入点，并有利于最终阐明失神癫痫的分子机制。     

利多卡因的脑保护机制

利多卡因具有脑保护作用，其机制与下列因素有关：阻断膜Na+-K+交换,ATP的消耗减少,因而减少自由基的产生,同时抑制缺血脑细胞Ｋ+外流及游离脂肪酸释放；抑制膜上电压依赖性Ca2+通道，减轻H2O2诱导的脂质过氧化反应；有效减轻缺血再灌注时神经细胞离子的紊乱,阻止细胞内Na+浓度的升高,降低突触前的谷氨酸释放；抑制线粒体的有氧代谢,降低线粒体内能量物质代谢速率,趋缓乳酸水平的升高,从而减轻细胞内乳酸的堆积,提高细胞对缺氧的耐受力；抑制缺血脑灌注后脑型肌酸激酶的释放,从而使脑缺血时的神经膜保持稳定；改善细胞渗透压和ATP的利用及Ca2+的清除等,从而起到保护神经的作用。     

生长抑素对人脐静脉内皮细胞Ca2+及其膜通道的调控研究

目的观察生长抑素(SOM)对人脐静脉内皮细胞(HUVEC)膜上Ca2+通道及胞浆内游离Ca2+浓度([Ca2+]i)的调控作用.方法应用共聚焦激光扫描显微术(CLSM)和膜片钳单通道记录技术对体培养HUVEC胞浆内[Ca2+]i、膜上Ca2+通道开放情况进行观察.结果SOM促使HUVEC胞浆内[Ca2+]i明显升高.胞膜上Ca2+通道的开放出现1～2 min的潜伏期后也开放但其开放概率明显降低.结论SOM对HUVEC胞浆内[Ca2+]i的调节可能首先通过细胞内储存的Ca2+释放及稍后的细胞膜上Ca2+通道开放,从而达到其调节效应.     

Regulation of STREX exon large conductance, calcium-activated potassium channels by the beta4 accessory subunit

Large conductance (BK-type) calcium-activated potassium channels utilize alternative splicing and association with accessory beta subunits to tailor BK channel properties to diverse cell types. Two important modulators of BK channel gating are the neuronal-specific beta4 accessory subunit (beta4) and alternative splicing at the stress axis hormone-regulated exon (STREX). Individually, these modulators affect the gating properties of the BK channel as well as its response to phosphorylation. In this study, the combined functional consequences of STREX and the mouse beta4 subunit on mouse BK channel biophysical properties were investigated in transfected HEK 293 cells. Surprisingly, we found that the combined effects of STREX and beta4 are non-additive and even opposite for some properties. At high calcium, beta4 and the STREX individually share properties that promote BK channel opening via slowing of deactivation. However, the combined effects are a speeding of deactivation and a decreased open probability. beta4 also inhibits BK channel opening by a slowing of activation. This effect occurs across calcium concentrations in the absence of STREX, but predominates only at low calcium for STREX containing channels. BK channel responses to phosphorylation status are also altered by the combination of the beta4 subunit and STREX. beta4/STREX channels show a slowing of activation kinetics following dephosphorylation whereas beta4 channels lacking STREX do not. In contrast, beta4 confers a speeding of activation in response to cyclic AMP-dependent phosphorylation in channels lacking STREX, but not in channels containing STREX. These results indicate that the combination of the beta4 subunit and STREX confers non-additive and unique properties to BK channels. Analysis of expression in brain slices suggests that STREX and beta4 mRNA overlap expression in the dentate gyrus of the hippocampus and the cerebellar Purkinje cells, suggesting that these unique properties of BK channels may underlie BK channel gating in these cells.     

Epinephrine activates outward rectifying K channel in Madin-Darby canine kidney cells

Patch-clamp recordings were used to study the epinephrine dependent activation of ion channels in the cell membrane of cultured subconfluent renal epithelial (MDCK) cells. The patch-current was dominated by two populations of K channels. The spontaneously active population of K channels shows an inward rectifying behavior. Addition of epinephrine to the cell exterior, after the patchpipette had been sealed to the cell membrane, increased the open probability of the inward rectifying K channel and shifted the membrane potential in the hyperpolarizing direction. The epinephrine induced hyperpolarization occurs in the range of seconds and is caused by activation of outward-rectifying K channels. The outward-rectifying K channel could not be observed under control conditions. Epinephrine activated channels always appeared in clusters of four to nine channels. Both populations of K channels are modulated in their open probability by cytoplasmic free calcium and voltage.     

血管活性肠肽对人脐静脉内皮细胞Ca~(2+)及其膜通道的调控

目的　观察血管活性肽 (VIP)对人脐静脉内皮细胞 (HUVEC)膜上Ca2 + 通道及胞浆内游离Ca2 +([Ca2 + ]i)的调控作用。方法　应用共聚焦激光扫描显微术 (CLSM)和膜片钳单通道记录技术对体外培养HU VEC胞浆内 [Ca2 + ]i、膜上Ca2 + 通道开放情况进行观察。结果　VIP促使HUVEC胞膜上Ca2 + 通过道的开放概率和胞浆内 [Ca2 + ]i 均明显升高。结论　IVP对HUVEC胞浆内 [Ca2 + ]i的调节可能除通过细胞内储存的Ca2 +释放外还依赖细胞膜上Ca2 + 通道开放 ,从而达到其调节效应