羊栖菜多糖对荷瘤小鼠红细胞膜Na+,K+-ATPase活性的影响

报道了羊栖菜多糖 （SFPS）对S180A小鼠,EAC小鼠,L615 小鼠红细胞膜Na+,K+-ATPase的活性的影响。结果表明：SFPS能明显抑制S180A小鼠,EAC小鼠,L615小鼠红细胞膜Na+,K+-ATPase的活性。本文结果提示,SFPS 的这一作用可能是其促进荷瘤小鼠红细胞免疫功能的机理之一。     

仙人掌多糖对荷瘤小鼠肿瘤细胞钙泵的影响

研究了食用仙人掌多糖、药用仙人掌多糖对S180小鼠肿瘤细胞膜Ca2 -ATPase的活性影响.结果表明,二者均能明显抑制荷瘤小鼠肿瘤细胞膜上Ca2 -ATPase的活性.仙人掌多糖的这一作用改变了荷瘤小鼠细胞膜的物质、能量平衡,推测其作用可能表现为促进肿瘤细胞的凋亡.     

秦皮乙素对S180小鼠肿瘤细胞膜功能的影响

研究秦皮乙素对S_(180)小鼠肿瘤细胞膜功能的影响.采用抑瘤实验检测秦皮乙素对S_(180)小鼠体内抗肿瘤活性;采用荧光光度法检测秦皮乙素对S_(180)小鼠肿瘤细胞膜流动性的影响;采用比色法检测秦皮乙素对S_(180)小鼠肿瘤细胞膜Na~+,K~+-ATPase和Ca~(2+),Mg~(2+)-ATPase活性、含唾液酸量、封闭度的影响.秦皮乙素各组小鼠平均瘤重均低于阴性对照组,均可降低肿瘤细胞膜流动性、Na+,K+-ATPase和Ca~(2+),Mg~(2+)-ATPase活性和膜封闭度,均可抑制肿瘤细胞膜唾液酸的生成.秦皮乙素抑制肿瘤细胞的生长与改变肿瘤细胞膜功能有关.     

库拉索芦荟多糖对S180小鼠红细胞膜脂流动性的影响

目的：研究库拉索芦荟多糖对S180荷瘤小红细胞膜脂流动性的影响。方法：采用荧光分光光度法进行研究，结果：库拉索芦荟多糖可使荷瘤小鼠红细胞膜微粘度下降，膜流动性升高。结论：库拉索芦荟多糖可以改善荷瘤机体的血液循环，提高红细胞免疫粘附肿瘤细胞的能力。     

芦荟多糖对荷瘤小鼠肿瘤细胞膜功能的影响

研究芦荟多糖对荷瘤小鼠肿瘤细胞膜功能的影响.采用荧光分光光度法、SDS-聚丙烯酰胺凝胶电泳以及唾液酸试剂盒分别测定库拉索和木立2种芦荟多糖对S180小鼠肿瘤细胞膜脂流动性、膜蛋白及唾液酸含量的影响.结果表明,2种芦荟多糖各剂量组均能不同程度地降低S180小鼠肿瘤细胞膜脂流动性、膜交联蛋白百分比含量和唾液酸的含量,且两种多糖中、高剂量组具有显著性(P<0 05或P<0 01).提示,芦荟多糖对S180小鼠肿瘤细胞膜功能具有抑制作用,提示其可能为芦荟多糖发挥抗肿瘤作用的主要机制之一.     

超重女性有氧运动对红细胞代谢的影响作用

有氧运动是人体在氧气充分供应的情况下进行的体育锻炼,红细胞代谢时可运输氧气,研究超重女性有氧运动对红细胞代谢产生的影响作用具有十分重要的意义。对64名超重女性进行为期三周的有氧运动。通过流式细胞检测法检测超重女性体内红细胞膜的PS外翻量,对有氧运动前后的血脂、PS外翻及Na+K+-ATPase和Ca2+Mg2+-ATPase酶三维活性进行检验。实验结果表明:有氧运动干预之前,轻度超重组女性体内的PS外翻量与其余两组有明显的差别(P≤0.05),HDL在轻度超重组和重度超重组之间有明显的区别;有氧运动干预后,Na+K+-ATPase的活性有显著提高(P≤0.05),红细胞膜的PS外翻量虽然有降低的趋势,但差异不显著。说明在红细胞脂质代谢紊乱的初期,红细胞膜PS外翻量比血脂指标更能体现超重女性的体重发展情况。有氧运动能够有效提高红细胞膜膜Na+K+-ATPase酶的活性,提高红细胞膜PS的外翻量,同时加快红细胞的代谢速度。     

龙葵碱对肿瘤细胞膜ATP酶活性的影响

荷瘤小鼠分为治疗组(37．50mg／kg、18．75mg／kg、9．37mg／kg)和对照组(生理盐水组、环磷酰胺组30mg／kg),分别测定各组肿瘤细胞膜的Na^ ,K^ -ATPase及Ca^2 ,Mg^2 -ATPase活性．结果表明龙葵碱(37．50mg／kg、18．75mg／kg)对S180小鼠及H22小鼠肿瘤细胞膜Na^ ,K^ -ATPase及Ca^2 ,Mg^2 -ATPase活性均有明显的抑制作用,并且其抑制作用呈量效正相关．因此龙葵碱这一作用可能是其抗肿瘤作用机理之一．     

大负荷跑台运动对大鼠心肌细胞膜Na+-K+-ATPase、Ca2+-ATPase与肌浆网Ca2+-ATPase活性的影响

目的:探讨大负荷跑台运动对大鼠心肌细胞膜钠钾泵(Na+-K+-ATPase)、钙泵(Ca2+-ATPase)与肌浆网钙泵(Ca2+-ATPase)活性的影响。方法:选择30只成年雄性SD大鼠分为空白对照组和运动后24 h组以及运动后即刻组。结果:运动后即刻组的Na+-K+-ATPase、Ca2+-ATPase活性均显著低于其他两组,(P<0.05);运动后24 h组的Ca2+-ATPase显著低于其他两组,(P<0.05);电镜观察可见运动后24 h组的肌细胞及肌浆网出现肿胀,肌原纤维结构出现明显的损伤;运动后即刻组的线粒体结构出现明显的损伤。结论:大负荷跑台运动会导致大鼠心肌细胞膜钠钾泵(Na+-K+-ATPase)、钙泵(Ca2+-ATPase)与肌浆网钙泵(Ca2+-ATPase)活性的降低。     

姜黄素对荷瘤小鼠红细胞免疫功能的影响

研究姜黄素对S180和H22荷瘤小鼠红细胞免疫功能的影响.观察姜黄素对荷瘤小鼠红细胞免疫黏附肿瘤细胞的能力;观察姜黄素对荷瘤小鼠红细胞免疫调节因子活性的影响;采用DPH荧光探针,用荧光偏振法测定荧光偏振度(P),并计算膜的微黏度(η)研究红细胞膜脂流动性(LFU).姜黄素能对两种荷瘤小鼠均具有非常显著的抑瘤作用;能够升高两种荷瘤小鼠的红细胞黏附肿瘤细胞的花环率;显著提高两种荷瘤小鼠红细胞C3b受体花环促进率,降低其抑制率;提高两种荷瘤小鼠的红细胞膜的流动性.姜黄素可能是通过提高两种荷瘤小鼠红细胞免疫调节因子活性及红细胞膜脂流动性.从而恢复荷瘤小鼠红细胞免疫功能进而达到抗肿瘤目的.     

锌-金属硫蛋白对力竭运动大鼠肝脏和股四头肌线粒体ATPase损伤的保护作用

通过锌-金属硫蛋白(Zn-MT)的补充干预观察对大鼠肝脏和股四头肌线粒体ATPase的影响,探讨Zn-MT对线粒体ATPase保护作用的机制.用雄性SD大鼠30只,随机分为安静对照组、运动对照组、补充Zn-MT+运动组.按Bedford运动模型运动至力竭后即刻处死,取肝脏和股四头肌制备线粒体备测.测定肝脏和股四头肌线粒体Na+,K+-ATPase、Ca2+-ATPase,Mg2+-ATPase活性,并进行有关统计学检验.结果表明,Zn-MT可以抑制由于力竭运动造成的肝脏和股四头肌中Na+,K+-ATPase、Ca2+-ATPase,Mg2+-ATPase活性的下降.     

还生口服液抗癌作用机制的研究

报道了还生口服液对荷瘤小鼠（Ｓ１８０、ＥＡＣ、Ｌ６１５）癌细胞膜、红细胞膜Ｎａ＋，Ｋ＋－ＡＴＰａｓｅ活性的影响和对荷瘤小鼠红细胞膜免疫功能的影响。结果表明，还生口服液可显著抑制癌细胞膜、荷瘤小鼠红细胞膜Ｎａ＋，Ｋ＋－ＡＴＰａｓｅ的活性，同时可显著提高荷瘤小鼠红细胞膜的免疫功能，可使红细胞免疫复合物花环率（ＲＦＩＲ）降低，而使红细胞Ｃ３ｂ受体花环率（ＲＢＣ—Ｃ３ｂＲＲ）、红细胞Ｃ３ｂ受体花环促进率（ＲＦＥＲ）显著提高。本文结果揭示，还生口服液抗癌作用机制有部分是通过抑制癌细胞膜，荷瘤机体红细胞膜Ｎａ＋，Ｋ＋－ＡＴＰａｓｅ的活性，提高荷瘤机体红细胞免疫功能完成的。     

薏苡仁酯对荷瘤小鼠红细胞免疫功能及Na~+,K~+-ATPase活性的影响

薏苡仁酯对荷瘤小鼠红细胞免疫功能具有显著的促进作用，对红细胞膜上的Ｎａ＋，Ｋ＋－ＡＴＰａｓｅ有抑制作用。其抑制作用呈量效正相关。薏苡仁酯的后一作用可能是其促进荷瘤小鼠红细胞免疫功能的机理之一。     

Crystal structure of the sodium-potassium pump

The Na+,K+-ATPase generates electrochemical gradients for sodium and potassium that are vital to animal cells, exchanging three sodium ions for two potassium ions across the plasma membrane during each cycle of ATP hydrolysis. Here we present the X-ray crystal structure at 3.5 A resolution of the pig renal Na+,K+-ATPase with two rubidium ions bound (as potassium congeners) in an occluded state in the transmembrane part of the alpha-subunit. Several of the residues forming the cavity for rubidium/potassium occlusion in the Na+,K+-ATPase are homologous to those binding calcium in the Ca2+-ATPase of sarco(endo)plasmic reticulum. The beta- and gamma-subunits specific to the Na+,K+-ATPase are associated with transmembrane helices alphaM7/alphaM10 and alphaM9, respectively. The gamma-subunit corresponds to a fragment of the V-type ATPase c subunit. The carboxy terminus of the alpha-subunit is contained within a pocket between transmembrane helices and seems to be a novel regulatory element controlling sodium affinity, possibly influenced by the membrane potential.     

Crystal structure of the plasma membrane proton pump

A prerequisite for life is the ability to maintain electrochemical imbalances across biomembranes. In all eukaryotes the plasma membrane potential and secondary transport systems are energized by the activity of P-type ATPase membrane proteins: H+-ATPase (the proton pump) in plants and fungi, and Na+,K+-ATPase (the sodium-potassium pump) in animals. The name P-type derives from the fact that these proteins exploit a phosphorylated reaction cycle intermediate of ATP hydrolysis. The plasma membrane proton pumps belong to the type III P-type ATPase subfamily, whereas Na+,K+-ATPase and Ca2+-ATPase are type II. Electron microscopy has revealed the overall shape of proton pumps, however, an atomic structure has been lacking. Here we present the first structure of a P-type proton pump determined by X-ray crystallography. Ten transmembrane helices and three cytoplasmic domains define the functional unit of ATP-coupled proton transport across the plasma membrane, and the structure is locked in a functional state not previously observed in P-type ATPases. The transmembrane domain reveals a large cavity, which is likely to be filled with water, located near the middle of the membrane plane where it is lined by conserved hydrophilic and charged residues. Proton transport against a high membrane potential is readily explained by this structural arrangement.     

Ion permeation through the Na+,K+-ATPase

P-type ATPase pumps generate concentration gradients of cations across membranes in nearly all cells. They provide a polar transmembrane pathway, to which access is strictly controlled by coupled gates that are constrained to open alternately, thereby enabling thermodynamically uphill ion transport (for example, see ref. 1). Here we examine the ion pathway through the Na+,K+-ATPase, a representative P-type pump, after uncoupling its extra- and intracellular gates with the marine toxin palytoxin. We use small hydrophilic thiol-specific reagents as extracellular probes and we monitor their reactions, and the consequences, with cysteine residues introduced along the anticipated cation pathway through the pump. The distinct effects of differently charged reagents indicate that a wide outer vestibule penetrates deep into the Na+,K+-ATPase, where the pathway narrows and leads to a charge-selectivity filter. Acidic residues in this region, which are conserved to coordinate pumped ions, allow the approach of cations but exclude anions. Reversing the charge at just one of those positions converts the pathway from cation selective to anion selective. Close structural homology among the catalytic subunits of Ca2+-, Na+,K+- and H+,K+-ATPases argues that their extracytosolic cation exchange pathways all share these physical characteristics.     

Extrusion of calcium from rod outer segments is driven by both sodium and potassium gradients

Calcium is transported across the surface membrane of both nerve and muscle by a Na+-dependent mechanism, usually termed the Na:Ca exchange. It is well established from experiments on rod outer segments that one net positive charge enters the cell for every Ca2+ ion extruded by the exchange, which is generally interpreted to imply an exchange stoichiometry of 3 Na+:1 Ca2+. We have measured the currents associated with the operation of the exchange in both forward and reversed modes in isolated rod outer segments and we find that the reversed mode, in which Ca2+ enters the cell in exchange for Na+, depends strongly on the presence of external K+. The ability of changes in external K+ concentration ([K+]o) to perturb the equilibrium level of [Ca2+]i indicates that K+ is co-transported with calcium. From an examination of the relative changes of [Ca2+]o, [Na+]o, [K+]o and membrane potential required to maintain the exchange at equilibrium, we conclude that the exchange stoichiometry is 4 Na+:1 Ca2+, 1 K+ and we propose that the exchange should be renamed the Na:Ca, K exchange. Harnessing the outward K+ gradient should allow the exchange to maintain a Ca2+ efflux down to levels of internal [Ca2+] that are considerably lower than would be possible with a 3 Na+:1 Ca2+ exchange.