Effect of cadmium on transmembrane Na+ and K+ transport systems in human erythrocytes.

The effects of cadmium (Cd2+) on Na+,K(+)-ATPase in disrupted human erythrocyte membranes and on various transmembrane Na+ and K+ transport systems in intact erythrocyte suspensions were studied. Cadmium2+ inhibited the erythrocyte Na+,K(+)-ATPase enzyme with a 50% inhibition at a Cd2+ concentration of 6.25 microM. The Cd2+ inhibition in the human erythrocyte was non-competitive with respect to Na+,K+, and ATP. Cadmium2+ exerted no acute effect, however, on the Na+,K(+)-ATPase pump activity as measured by the ouabain sensitive 86Rb uptake or Na+ efflux in intact red blood cells. Cadmium2+ also inhibited the Ca2+ dependent K+ channels in human red blood cells, whereas it had no effect on Na+,K+ cotransport, Na+,Li+ countertransport, anion carrier, and the number of active Na+ pump units. The data indicate that in human erythrocytes under acute conditions Cd2+ exerts an inhibitory effect on Na+,K(+)-ATPase enzyme in disrupted erythrocytes and the Ca2+ stimulated K+ efflux in intact red blood cells without affecting the Na+ pump, Na+,K+ cotransport, and Na+,Li+ countertransport activity.     

Effect of cadmium on transmembrane Na+ and K+ transport systems in human erythrocytes.

The effects of cadmium (Cd2+) on Na+,K(+)-ATPase in disrupted human erythrocyte membranes and on various transmembrane Na+ and K+ transport systems in intact erythrocyte suspensions were studied. Cadmium2+ inhibited the erythrocyte Na+,K(+)-ATPase enzyme with a 50% inhibition at a Cd2+ concentration of 6.25 microM. The Cd2+ inhibition in the human erythrocyte was non-competitive with respect to Na+,K+, and ATP. Cadmium2+ exerted no acute effect, however, on the Na+,K(+)-ATPase pump activity as measured by the ouabain sensitive 86Rb uptake or Na+ efflux in intact red blood cells. Cadmium2+ also inhibited the Ca2+ dependent K+ channels in human red blood cells, whereas it had no effect on Na+,K+ cotransport, Na+,Li+ countertransport, anion carrier, and the number of active Na+ pump units. The data indicate that in human erythrocytes under acute conditions Cd2+ exerts an inhibitory effect on Na+,K(+)-ATPase enzyme in disrupted erythrocytes and the Ca2+ stimulated K+ efflux in intact red blood cells without affecting the Na+ pump, Na+,K+ cotransport, and Na+,Li+ countertransport activity.     

Maternal ethanol consumption: effect on (Na+-K+)-ATPase in rat offspring

The activity of Mg2+-activated, ouabain-sensitive adenosine triphosphatase, (Na+-K+)-ATPase, was determined in homogenates of hypothalamus, cortex, cerebellum, and brain stem from the 19-day-old offspring of rats that were pair-fed control or (6.6%, v/v) ethanol liquid diets on a chronic basis prior to parturition. In the offspring of both control and ethanol-fed rats the specific activity of (Na+-K+)-ATPase was significantly (p less than 0.01) greater in the cortex than it was in the hypothalamus, brain stem or cerebellum (hypothalamus approximately brain stem approximately cerebellum). When the offspring of ethanol-fed and control rats were compared we observed no significant (p greater than 0.05) differences in the activity of (Na+-K+)-ATPase in any of the four brain regions examined. In addition, the results of kinetic analyses of cortical (Na+-K+)-ATPase were similar in the 19-day-old offspring of ethanol-fed rats and those whose mothers consumed either the control liquid diet or standard laboratory chow. The results of these studies suggest that the activity of the plasma membrane enzyme, (Na+-K+)-ATPase, was not affected in the 19-day-old offspring of ethanol-fed rats.     

bFGF对慢性酒精中毒大鼠脑和肝组织ATP酶活力的影响

[目的]观察碱性成纤维细胞生长因子(bFGF)对慢性酒精中毒大鼠脑组织及肝组织Na+-K+-ATP酶活力和Ca2+-Mg2+-ATP酶活力,探讨bFGF对慢性酒精中毒所致的脑损伤、肝损伤的保护作用。[方法]选择成年Wistar雄性大鼠,采用白酒灌胃建立慢性酒精中毒模型,慢性酒精中毒模型建立成功的大鼠随机抽签法分为酒精中毒对照组、生理盐水(NS)对照组和bFGF治疗组,每组10只。另10只不灌白酒作为正常对照组。bFGF治疗组大鼠白酒灌胃的同时,1 h后按12μg/kg剂量肌肉注射,共14 d。各组大鼠到相对应的时间点取出各组大鼠脑组织、肝组织制成匀浆,测定脑组织、肝组织匀浆中Na+-K+-ATP酶活力和Ca2+-Mg2+-ATP酶活力。[结果]与正常对照组相比,慢性酒精中毒后大鼠脑组织及肝组织中Na+-K+-ATP酶活力和Ca2+-Mg2+-ATP酶活力均明显降低(P﹤0.01);经bFGF治疗后脑组织及肝组织中Na+-K+-ATP酶活力和Ca2+-Mg2+-ATP酶活力均明显高于酒精中毒对照组及NS对照组(P﹤0.05)。[结论bFGF能提高慢性酒精中毒脑组织和肝组织中Na+-K+-ATP酶活力及Ca2+-Mg2+-ATP酶活力,提示bFGF对慢性酒精中毒所致的脑损伤和和肝损伤具有保护作用。     

Effects of manganese on rat brain microsomal Mg2+-Na+-K+-ATPase: in vivo and in vitro studies

The effect of manganese on brain microsomal Mg2+-Na+K+-ATPase was examined both in vitro and in vivo. Daily intraperitoneal administration of MnCl2 . 4H2O (Mn2+, 6 mg/kg) to the rats for a period of 90 days produced 10% (P less than 0.05) inhibition in the activity of Mg2+-ATPase, and 72 and 63% increases in the contents of manganese and copper, respectively, in the microsomal fraction of brain. In in vitro studies, lower concentrations of Mn2+ activated while higher concentrations inhibited the activity of brain microsomal ATPase. Addition of equal concentrations of Mn2+ + Cu2+ (8 mM) in vitro produced 8% inhibition in the activity of Mg2+-ATPase and 83% inhibition in Na+-K+-ATPase. Free Cu2+ ions were able to antagonize the effect of Mn2+ on ATPase in vitro and inhibited the activity of Mg2+-Na+-K+-ATPase with more pronounced effect of Na+-K+-ATPase. The lack of change in the activity of Na+-K+-ATPase in the brain microsomes of rats administered manganese, in spite of a significant increase in copper, could not be explained. It is, however, evident that a manganese-induced elevation in brain copper was not responsible for initiating biochemical changes in manganese neurotoxicity.     

Effects of chronic treatment with cadmium on ATPases, uptake of catecholamines, and lipid peroxidation in rat brain synaptosomes

The chronic effects of cadmium on specific activities of oligomycin-sensitive (OS) and -insensitive Mg2+ ATPase, Na(+)-K+ ATPase, lipid peroxidation, and uptake of catecholamines in brain synaptosomes of rats treated daily for 2 or 4 months were studied. Cadmium significantly decreased the specific activities of OS-Mg2+ ATPase, Na(+)-K+ ATPase, and uptake of [3H]-dopamine (3H-DA) and [3H]norepinephrine (3H-NE) and increased the lipid peroxidation.     

Effects of gossypol on the activity of kidney (Na+ + K+)-ATPase and the functions of erythrocyte membrane

Gossypol extracted from cottonseed oil, reputed to exert contraceptive action in males, may induce a side effect of hypokalemia. The cellular and molecular mechanisms by which gossypol produces hypokalemia are not quite understood. We have examined the inhibitory effect of gossypol on the activity of (Na+ + K+)-ATPase purified from the outer medulla of rabbit kidney, the half maximal inhibitory concentration (IC50) is 6.5 micron. The kinetic studies using this enzyme preparation show that gossypol is noncompetitive with ATP, Mg2+, Na+ and K+ with apparent Ki of 15.0, 13.0, 14.0 and 4.4 micron, respectively. On the other hand, in order to estimate the effects of gossypol on membrane transport of intact cells, we have investigated the effects of gossypol on the activity of (Na+ + K+)-ATPase, membrane integrity and permeability of human erythrocytes. It shows that gossypol inhibited the enzyme activity (greater than 5 micron) and expressed the hemolysis (greater than 50 micron) in vitro in a concentration-dependent manner, and increased the K+-efflux of the cells (10-40 micron). The above effects are antagonized by 1-2% bovine serum albumin. The data demonstrate that gossypol is a specific and potent membrane active agent. These results may be relevant to the in vivo actions of gossypol.     

茶多酚对甲基汞致大鼠神经毒性影响

目的研究甲基汞致大鼠神经毒性的作用机制,探讨茶多酚对甲基汞致神经毒性作用的影响。方法36只Wistar大鼠随机分成3组,对照组,染汞组(12μmol/kg),茶多酚干预组(1 mmol/kg),连续干预染毒4周,最后1次染毒后24 h,将大鼠麻醉后处死,断头取脑,冰浴下分离大脑皮质,测定Na+-K+-ATP酶、Ca2+-ATP酶活力及细胞内Ca2+、活性氧簇(ROS)含量及细胞凋亡情况。结果与对照组比较,单纯染汞组Na+-K+-ATP酶[(2.72±0.46)μmol/(h.mg)]、Ca2+-ATP酶活力[(1.52±0.26)μmol/(h.mg)]明显降低(P<0.01),细胞内Ca2+含量(239.52±44.84)nmol/L、ROS含量(313.86±35.11)及细胞凋亡率[(40.84±6.26)%]明显升高(P<0.01);与染汞组比较,茶多酚干预组Na+-K+-ATP酶活力[(3.58±0.71)μmol/(h.mg)]、Ca2+-ATP酶活力[(1.98±0.29)μmol/(h.mg)]明显升高(P<0.05或P<0.01),细胞内Ca2+含量(188.39±7.43)nmol/L、ROS含量(238.03±22.99)及细胞凋亡率[(28.31±4.34)%]明显降低(P<0.05或P<0.01)。结论茶多酚对甲基汞致大鼠神经毒性有一定拮抗作用。     

Reduced ion transport in erythrocytes of male Sprague-Dawley rats during starvation

Although several studies have suggested that the reduced activity of the Na+-K+ pump during starvation is a source of energy conservation, the hypothesis has not been tested in intact cells, nor has the contribution of passive permeability been considered in a controlled animal study. In this study three components of K+ influx (Na+-K+ pump = ouabain sensitive, cotransport = bumetanide sensitive and leak = both ouabain and bumetanide insensitive) and Na+ influx were measured with 42K+ and 24Na+ in intact red blood cells of adult male rats. During starvation rats lost an average of 28% of their body weight; pump K+ influx in cells stabilized for 2 h in incubation medium fell from 7.03 +/- 0.74 (SEM) to 4.82 +/- 0.25 mueq/(mL cells.h) with cell [Na+] of 6.4 +/- 0.9 and 4.4 +/- 0.2 mmol/L cells, respectively. Maximized Na+-K+ pump activity in Na+-loaded cells was also lower in cells of starved rats than in those of controls and was inversely correlated with extent of weight loss in the starved rats. Leak K+ influx was reduced from 0.73 +/- 0.08 to 0.47 +/- 0.03. Lower Na+ influx in cells of starved rats was not significant statistically, although alteration in passive Na+ transport was apparent. The results indicate decreases in both active and passive components of ion turnover of erythrocytes of rats during starvation.     

Influence of environmental lead on membrane ion transport in a French urban male population.

Red cell cation transports (Na(+)-K+ pump, Na(+)-K+ cotransport system, Na(+)-Li+ countertransport, and Na+ and K+ passive permeabilities) and blood and hair lead levels were measured in 129 healthy adult Caucasians not occupationally exposed to lead. In agreement with previously reported in vitro results showing a lead-induced Na(+)-K+ ATPase inhibition, Na(+)-K+ pump activity was inversely correlated with hair lead (r = -0.18, P less than 0.05); it was not significantly correlated with blood lead. Na(+)-K+ cotransport activity was inversely correlated with blood lead contents (r = -0.23, P less than 0.05) but not with hair lead. No significant correlation was found between the remaining cation transport pathways and lead levels. It is hypothesized that environmental, long-term exposure to lead may result in pump inhibition, while a recent exposition to lead may result in inhibition of the Na(+)-K+ cotransport system. Further research is required in order to determine if red cell Na(+)-K+ pump and Na(+)-K+ cotransport activities are sensitive indicators of chronic and recent exposures to lead, respectively.     

类毒素-A对PC12细胞内ATP酶活力的影响

目的 研究类毒素-A（ANTX-A）对PC12细胞内ATP酶活力的影响.方法 用不同浓度（0、10^-9、10^-8、10^-7mol/L）ANTX-A刺激PC12细胞1 h,或10^-7mol/L ANTX-A刺激PC12细胞不同时间（0、30、60、90min）后,诱导PC12细胞激活;2相刺激方法（用ANTX-A 2次处理PC12细胞）诱导PC12细胞脱敏;用比色法测定这2种状态下胞内Na^＋-K^＋-ATP酶和Ca^2＋-ATP酶活力.结果 10^-9、10^-8、10^-7mol/L ANTX-A激活PC12细胞1 h和10-7 mol/L ANTX-A激活PC12细胞30、60、120 min时,胞内Na^＋-K^＋-ATP酶活力均有下降趋势,Ca^2＋-ATP酶活力在不同激活状态均比对照组显著降低（P＜0.05,P＜0.01）,有明显的剂量-反应关系和时间-效应关系.在2相脱敏试验中,当第1相ANTX-A浓度为10^-8、10^-7mol/L时,所对应脱敏状态胞内Na^＋-K^＋-ATP酶活力也均有减少趋势,Ca^2＋-ATP酶活力比相应激活状态明显降低（P＜0.01）.结论 Ca^2＋-ATP酶在ANTX-A激活和脱敏PC12细胞过程中可能有重要调节作用.     

Effect of norepinephrine on inhibition of mouse brain (Na+ + K+)-stimulated, (Mg++)-dependent, and (Ca++)-dependent ATPase activities by ethanol

Norepinephrine (0.1 mM) has been reported to "sensitize" (Na+ + K+)-ATPase activity of rat brain homogenates to inhibition by ethanol. The present study extends these investigations to the mouse and includes other ATPase activities. We measured the effects of norepinephrine on the sensitivity of ethanol-induced inhibition of (Na+ + K+)-stimulated (E.C. 3.6.1.3), (Mg++)-dependent (E.C. 3.6.1.4) and (Ca++)-dependent ATPase activities. Whole forebrains from C57BL/6J mice were homogenized and assayed in vitro for ATPase activity using standard conditions. Ethanol (0.125-2.0 M) caused a dose-dependent inhibition of all three ATPases. Norepinephrine (0.1 mM) had no appreciable effect on ethanol's inhibition of (Na+ + K+)-stimulated or (Ca++)-dependent ATPase activities, but slightly antagonized ethanol's effect on (Mg++)-ATPase. These results suggest that norepinephrine has little effect on the sensitivities of specific ATPases to ethanol inhibition in mouse brain.     

鱼藤酮染毒大鼠纹状体某些生化指标的变化

目的观察鱼藤酮染毒对大鼠纹状体某些生化指标的影响。方法采用微量渗透泵背部埋植法观察不同剂量鱼藤酮对大鼠纹状体的影响,利用Fluoro-JadeB复合荧光尼氏染色观察染毒大鼠纹状体神经细胞的改变情况,高效液相色谱法(HPLC)检测纹状体ATP、ADP和AMP含量,采用生化实验分析Na+-K+-ATP酶和Ca2+-ATP酶的活性。结果染毒大鼠纹状体内出现大量的阳性变性神经细胞,而溶剂对照组未出现类似改变。与溶剂对照组比较,2.0和4.0mg/kg鱼藤酮组大鼠纹状体ATP含量出现显著性降低(P0.01),ADP和AMP含量则相对升高;Na+-K+-ATP酶与Ca2+-ATP酶的活性随染毒剂量的增大出现不同程度的抑制,差异具有统计学意义。结论鱼藤酮可导致纹状体ATP含量降低及Na+-K+-ATP酶与Ca2+-ATP酶活性被抑制。     

魔芋多糖对小鼠肠道吸收功能的抑制作用与机制

目的探讨魔芋多糖(konjac polysaccharide,KP)对小鼠肠道吸收功能的抑制作用与机制。方法将实验动物分为正常对照(N)、高脂(HF)和KP高、中、低剂量(KPH、KPM、KPL)共5个组,连续喂饲20d。紫外分光光度法测定小肠粘膜Na+-K+-ATP酶活性,血糖仪测定血糖并称量体重和粪便湿、干重等。结果HF组和KPH组的Na+-K+-ATP酶活性分别为16.2±1.48和11.2±1.10μmolPi/(mgpro·h),体重和餐后血糖分别为34.3±2.07g、7.5±1.15mmol/L和28.1±1.95g、4.8±0.73mmol/L。两组间各项指标的差别均有显著性意义(P<0.05)。结论KP降低小鼠餐后血糖和血清胆固醇水平,抑制体重增长、降低小肠粘膜Na+-K+-ATP酶活性,对肠道吸收功能有抑制作用。     

铅对家兔脑组织血管内皮物质及ATP酶活力的影响

目的探讨铅对家兔脑组织一氧化氮含量及ATP酶活力的影响及其机制。方法将32只家兔随机分为1个对照组和高、中、低3个染铅剂量组。经不同剂量醋酸铅灌胃染毒5d后,测定各组脑组织中内皮素（ET）、一氧化氮（NO）的含量及Na^＋-K^＋-ATP酶和Ca^2＋-Mg^2＋-ATP酶的活力。结果高、中剂量染毒组ET浓度较对照组显著升高（P〈0.05,P〈0.01）,3个剂量染毒组NO浓度均较对照组显著降低（P〈0.05,P〈0.01）;高、中剂量染毒组Na^＋-K^＋-ATP酶、Ca^2＋-Mg^2＋-ATP酶活力均较对照组显著降低（P〈0.05,P〈0.01）。结论铅可造成家兔脑组织血管内皮活力物质及ATP酶活力的异常,这种改变可能与铅所致中枢神经系统功能损害有关。     

Rapid hypertensinogenic effect of lead: studies in the spontaneously hypertensive rat.

Chronic lead exposure may cause hypertension in normotensive rats. This hypertensinogenic effect has been attributed to perturbations in the renin-angiotensin axis, the contractile response of the vascular smooth muscle, or the intracellular Ca2+ homeostasis as a consequence of the inhibition of Na(+)-K(+)-ATPase activity. In this study we examined the short-term effect of lead exposure on blood pressure, plasma renin activity, vascular contractility, and renal Na(+)-K(+)-ATPase activity and abundance in the spontaneously hypertensive rat. Our data indicate that modest lead exposure caused blood pressure elevation within two weeks in this rat strain that is genetically susceptible to the development of hypertension. This rapid blood pressure-elevating effect did not appear to depend on the mechanisms described in hypertension associated with more chronic lead exposure listed above. This acute model provides an additional approach to the study of lead-induced hypertension.     

Effects of nitrogen dioxide on red blood cells of rats: alterations of cell membrane components and populational changes of red blood cells during in vivo exposure to NO2

Male Wistar rats were exposed to 4 ppm NO2 for 10 days in order to examine the relationship between the changes in components of red cell membranes and alterations of erythrocyte population. Na+, K+-ATPase activity of red blood cell membranes of exposed animals showed a significantly higher value than that of the control at the first and fourth days of exposure and then decreased to under the control value at the seventh day. In order to examine changes in erythrocyte population, red blood cells were fractionated into four fractions according to their density using Dextran density centrifugation. The alteration of the percentage of lowest-density cells (fraction IV) of exposed animals was completely consistent with that of Na+,K+-ATPase activity in addition to that of the sialic acid content as described in a previous report (K. Kaya, T. Miura, and K. Kubota (1980). Environ. Res. 23, 397-409.). The percentage of fraction IV was 1.43- (P less than 0.05) and 1.68-fold (P less than 0.01) those of the control at the first and fourth days of exposure, respectively, and then decreased to under the control value at the seventh day. This decrease accompanied increases in the percentages of higher-density cells (fractions I and II). Examination of subfractions of red blood cells showed that Na+,K+-ATPase activity and the sialic acid content of three fractions with lower densities have higher values in exposed animals than in the control 1 day after exposure to NO2. Based on these results, it is concluded that increases in Na+,K+-ATPase activity and the sialic acid content occurring 1 day after exposure to 4 ppm NO2 were caused by elevated levels of these components in three fractions with lower densities as well as by an increase in the percentage of lowest-density cells in the erythrocyte population. It was also suggested that NO2 inhalation accelerated aging of erythrocytes with respect to density. The change in Ca2+,Mg2+-ATPase activity, in addition to that in the hexose content as described in a previous report (Kaya et al., 1980), was different from those in the sialic acid content and Na+,K+-ATPase activity. Ca2+,Mg2+-ATPase activity and the hexose content of exposed animals showed slightly reduced values 1 day after exposure to NO2. In all subfractions of red blood cells these values were slightly lower in exposed animals than in the controls. Therefore, reduction in Ca2+,Mg2+-ATPase activity and the hexose content is not due to changes in erythrocyte population.     

铅对心肌酶、钠钾泵、钙镁泵活性以及肾素、血管紧张素Ⅱ活性影响探讨

本研究同时测定了铅作业组、非铅作业组两组对象红细胞钠-钾泵、钙-镁泵活性、血浆肾素活性、血管紧张素Ⅱ以及血清心肌酶CMB、CPK、LDH活性。结果发现两组间钠-钾汞、钙-镁泵活性以及血浆肾素活性、血管紧张素Ⅱ均无显著差异,但铅作业组CMB水平与血铅水平呈正相关,提示铅负荷增加情况下可能导致心肌细胞损伤。心肌细胞受损是铅作业工人心功能受损的可能机制之一。     

Influence of thymic fraction 5 on erythrocyte (Na+ + K+)-ATPase activity in hypercholesterolemic rabbits

The effects of thymus fraction 5 injection on cholesterol, triglyceride and phospholipid levels in plasma and erythrocytes as well as on membrane-bound (Na+ + K+)-ATPase activity were investigated in rabbits fed a high-cholesterol diet for 3 months. While cholesterol feeding caused an increase in plasma and erythrocytes phospholipid levels, (Na+ + K+)-ATPase activity was found to be reduced. After high-cholesterol diet, the rabbits were given normal diet with or without thymosin F5 injections every other day for 21 days. Thymosin F5 treatment caused a significant decrease in plasma and erythrocyte phospholipid levels whereas membrane-bound (Na+ + K+)-ATPase activity was increased significantly. It is concluded that hypercholesterolemic lesions and the decreased erythrocyte ATPase activity may be eliminated by thymic extracts in rabbits.     

氟对大鼠红细胞膜Na~＋－K~＋－ATPase、Ca~（2＋）－ATPase活性的影响及“抗氟灵”的拮抗作用研究

选择健康雄性Ｗｉｓｔａｒ大鼠４０只,随机分为５组,观察氟对大鼠红细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ、Ｃａ２＋－ＡＴＰａｓｅ活性的影响及“抗氟灵”的拮抗作用。染毒及给药方式为自由饮式,染毒剂量为１８０ｍｇＦ－／Ｌ“抗氟灵浓度为２４ｇ％;染毒时间为２个月,“抗氟灵”治疗时间为１个半月。结果显示,染氟组动物红细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ、Ｃａ２＋－ＡＴＰａｓｅ活性均有显著升高,给予氟＋“抗氟灵”组比染氟组显著降低;氟中毒后给予“抗氟灵”治疗组明显低于治疗对照组。提示氟对红细胞膜Ｎａ＋－Ｋ＋－ＡＴＰａｓｅ、Ｃａ２＋－ＡＴＰａｓｅ活性有促进作用,而“抗氟灵”具有拮抗氟的作用