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Effects of eicosapentaenoic acid and docosahexaenoic acid on plasma membrane fluidity of aortic endothelial cells

LIPIDS 1999年第12期34卷 1297-1304页

作者： Hashimoto, M Hossain, MS Yamasaki, H Yazawa, K Masumura, S Shimane Med Univ Dept Physiol Izumo Shimane 6938501 Japan Sagami Chem Res Ctr Sagamihara Kanagawa 229 Japan

We investigated the relative effects of n-3 eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) on the plasma membrane fluidity of endothelial cells (EC) cultured from the thoracic aorta by determining fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) and its cationic derivative trimethylamino-DPH (TMA-DPH). Fluidity assessed by TMA-DPH demonstrated no significant differences in plasma membranes of vehicle (dimethyl sulfoxide;DMSO)-, EPA-, and DHA-treated EC. Plasma membrane fluidity assessed by DPH polarization, however, was significantly higher in the order of DHA > EPA > DMSO. Total cholesterol content decreased significantly by 28.4 and 15.9% in the plasma membranes of DHA- and EPA-treated cells, respectively. Total phospholipid content remained unaltered in the plasma membranes of the three groups of cells;however, the molar ratio of total cholesterol to phospholipid decreased significantly only in the membranes of DHA-treated EC. The unsaturation index in the plasma membranes of EPA- and DHA-treated cells increased by 35.7 and 64.3%, respectively, compared with that in the plasma membranes of control cells. The activities of catalase and glutathione peroxidase in the whole-cell homogenates, and levels of lipid peroxides in either the whole-cell homogenates or in plasma membrane fractions were not altered in EPA- or DHA-treated EC. These results indicate that the influence of DHA is greater than that of EPA in increasing plasma membrane fluidity of vascular EC. We speculate that the greater effect of DHA compared to EPA is due to its greater ability to decrease membrane cholesterol content or the cholesterol/phospholipid molar ratio, or both, and also to its greater ability in elevating the unsaturation index in the plasma membranes of EC.

关键词：主动脉/代谢过氧化氢酶/代谢细胞膜/药物作用细胞培养的胆固醇/代谢二苯己三烯/类似物和衍生物二十二碳六烯酸类/药理学二十碳五烯酸/药理学内皮血管/药物作用脂肪酸类/代谢荧光染料谷胱甘肽过氧化酶/代谢过氧化脂质类/代谢膜流动性/药物作用磷脂类/代谢大鼠 Wistar 动物女(雌)性大鼠

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Modulation of liposomal membrane fluidity by flavonoids and isoflavonoids

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ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 2000年第1期373卷 102-109页

作者： Arora, A Byrem, TM Nair, MG Strasburg, GM Michigan State Univ Dept Food Sci & Human Nutr E Lansing MI 48824 USA Michigan State Univ Dept Hort Bioact Nat Prod Lab E Lansing MI 48824 USA Michigan State Univ Natl Food Safety & Toxicol Ctr E Lansing MI 48824 USA

The polyphenolic structures of flavonoids and isoflavonoids confer them with the ability to scavenge free radicals and to chelate transition metals, a basis for their potent antioxidant abilities, Another possible contributory mechanism toward their antioxidant activities is their ability to stabilize membranes by decreasing membrane fluidity, In this study, the effects of representative flavonoids, isoflavonoids, and their metabolites on membrane fluidity and their preferential localization in the membrane were investigated using large unilamellar vesicles (LUVs) as the membrane models, These results were compared with those of cholesterol and alpha-tocopherol. Changes in fluorescence anisotropy values for a series of n-(9-anthroyloxy) fatty acid probes (n = 6, 12, 16) upon addition of the test compounds were used to monitor alterations in membrane fluidity at graded depths in lipid bilayer. The results of the study suggest that the flavonoids and isoflavonoids, similar to cholesterol and alpha-tocopherol, partition into the hydrophobic core of the membrane and cause a dramatic decrease in lipid fluidity in this region of the membrane. Localization of flavonoids and isoflavonoids into the membrane interiors and their resulting restrictions on fluidity of membrane components could sterically hinder diffusion of free radicals and thereby decrease the kinetics of free radical reactions. (C) 2000 Academic Press.

关键词：色满类/药理学黄烷酮类类黄酮物质/药理学荧光偏振荧光染料染料木黄酮/药理学异黄酮类/药理学脂质体/化学脂质体/药物作用膜流动性/药物作用棕榈酸类芦丁/药理学硬脂酸类

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Hepatotoxicity of tacrine: Occurrence of membrane fluidity alterations without involvement of lipid peroxidation

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JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS 2000年第1期294卷 160-167页

作者： Galisteo, M Rissel, M Sergent, O Chevanne, M Cillard, J Guillouzo, A Lagadic-Gossmann, D Univ Rennes 1 Fac Sci Pharmaceut & Biol INSERM U456 F-35043 Rennes France

Tacrine (THA), used in the treatment of Alzheimer's disease, is known to induce hepatotoxicity, the mechanisms of which remain to be fully established. We have previously shown that THA reduced intracellular glutathione concentration in rat hepatocytes in primary culture, thus pointing to a possible role for oxidative stress in THA toxicity. To test this, the effects of antioxidant molecules, namely, the flavonoids silibinin, silibinin dihydrogensuccinate, and silymarin, were evaluated on the toxicity of THA in cultured rat hepatocytes. This toxicity was investigated after a 24-h treatment over a concentration range from 0 to 1 mM, in the presence or absence of antioxidant (1 and 10 mu M). We found that simultaneous treatment of hepatocytes with any of the antioxidants and THA remained ineffective on the lactate dehydrogenase release induced by THA. Then, the production of lipid-derived radicals (to estimate lipid peroxidation) was measured in THA (0.05-0.50 mM)-treated cells using a spin-trapping technique coupled to electron paramagnetic resonance (EPR) spectroscopy. No increase of the EPR signal was observed over the period of 30 min to 24 h. In contrast, treatment of cells with the spin label 12-doxyl stearic acid followed by EPR spectroscopy showed that THA (0.05 and 0.25 mM) rapidly increased hepatocyte membrane fluidity. Extracellular application of GM1 ganglioside (60 mu M) both reversed this increase in fluidity and partially reduced lactate dehydrogenase release on THA exposure. In conclusion, this work indicates that early alterations of membrane fluidity, not resulting from lipid peroxidation, are likely to play an important role in the development of THA toxicity.

关键词：细胞培养的胆碱酯酶抑制剂/毒性电子自旋共振谱学 G(M1)神经节苷脂/药理学氢离子浓度 L-乳酸脱氢酶/分泌脂质过氧化作用/药物作用肝/药物作用膜流动性/药物作用大鼠 Sprague-Dawley 水飞蓟素/药理学他克林/毒性动物男(雄)性大鼠

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Glucocorticoid-induced alterations of renal sulfate transport

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JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS 2000年第2期294卷 658-663页

作者： Sagawa, K Darling, IM Murer, H Morris, ME SUNY Buffalo Dept Pharmaceut Amherst NY 14260 USA Univ Zurich Inst Physiol Zurich Switzerland

Glucocorticoid administration decreases renal sodium/phosphate cotransport in the proximal tubule due to a down-regulation of the sodium/phosphate cotransporter but has no effect on the sodium-dependent transport of glucose or proline. The objectives of the present investigation were to determine the effects of the glucocorticoid methylprednisolone (MPL) on 1) inorganic sulfate renal clearance in rats in vivo, 2) sodium/sulfate cotransport in kidney cortex membrane vesicles, and 3) the cellular mechanism of the MPL-induced alterations in sulfate renal transport. Male adrenalectomized Wistar rats received an i.v. dose of 50 mg/kg MPL or the vehicle. Urine samples were collected for 12 h after the administration of MPL, and blood samples were collected at the midpoint of the urine collection. Other animals were sacrificed at 4, 6, and 12 h after MPL administration, and the kidney cortex was removed for RNA or membrane preparations. Kidney cortex sodium/sulfate cotransporter (NaSi-1) mRNA levels were determined by reverse transcription-polymerase chain reaction and NaSi-1 protein levels were determined by enzyme-linked immunosorbent assay. The urinary excretion rate and renal clearance of sulfate were significantly increased in MPL-treated animals (144.0 +/- 27.0 versus 65.3 +/- 21.3 mu mol/12 h/kg and 0.208 +/- 0.038 versus 0.078 +/- 0.025 ml/min/kg, mean +/- S.E., n = 9-12 in treated versus control). The V-max value for sodium-dependent sulfate transport in brush border membrane vesicles (representing reabsorption in the proximal tubules) was significantly decreased in MPL-treated animals compared with controls (0.68 +/- 0.07 versus 0.88 +/- 0.05 nmol/mg of protein/10 s, mean +/- S.E.). There was no change in the K-m value for sodium/sulfate cotransport in brush-border membrane and no change in sulfate/anion exchange in basolateral membrane vesicles. Membrane fluidity in brush border membrane and basolateral membrane vesicles, determined by the fluorescence polarizat

关键词：消炎药/药理学生物转运载体蛋白质类/代谢阳离子转运蛋白质类荧光偏振糖皮质激素类/药理学肾皮质/药物作用肾皮质/代谢动力学膜流动性/药物作用甲泼尼龙/药理学微绒毛/药物作用微绒毛/代谢 RNA 信使/代谢大鼠 Wistar 硫酸盐类/血液硫酸盐类/代谢硫酸盐类/尿协同转运子动物男(雄)性大鼠

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Oxytocin receptors and cholesterol: interaction and regulation

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EXPERIMENTAL PHYSIOLOGY 2000年第Sup1期85卷 41S-49S页

作者： Gimpl, G Burger, K Politowska, E Ciarkowski, J Fahrenholz, F Johannes Gutenberg Univ Mainz Inst Biochem D-55099 Mainz Germany Univ Gdansk Dept Chem PL-80952 Gdansk Poland

Cholesterol affects the ligand binding function of the oxytocin receptor in a highly specific manner. While the structurally-related cholecystokinin receptor shows a strong correlation between the membrane fluidity and its binding function, the oxytocin receptor behaves differently. A stringent and unique requirement of the affinity state of the oxytocin receptor for structural features of the sterol molecule has been found. The molecular requirements differ both from those postulated for sterol-phospholipid interactions and from those known to be necessary for the activity of other proteins. Employing a new detergent-free subcellular fractionation protocol, a two-fold enrichment of the oxytocin receptors (10-15% of total receptors) has been detected in the cholesterol-rich, caveolin-containing membrane domains of the plasma membrane. While most of the properties of the oxytocin receptors were indistinguishable in cholesterol-poor versus cholesterol-rich membrane compartments, high-affinity oxytocin receptors localised in caveolin-enriched low-density membranes showed about a 3-fold higher stability against thermal denaturation at 37 degrees C compared with the oxytocin receptors localised in high-density membranes. Moreover, addition of cholesterol to the cholesterol-poor high-density membranes fully protected the oxytocin receptors against thermal denaturation and partially rescued high-affinity oxytocin binding. Although the membrane fluidity of the caveolin-enriched domains was lower than that in the high-density membranes, there was no correlation between the stability of oxytocin receptors and the fluidity level of the membrane domains. Finally, in a molecular modelling approach a putative cholesterol binding motif on the extracellular surface of the oxytocin receptor was found.

关键词：结合部位/药物作用结合部位/生理学窖蛋白1 细胞质膜微囊蛋白细胞膜/化学细胞膜/代谢细胞培养的胆固醇/代谢胆固醇/药理学基因报告绿色荧光蛋白质类指示剂和试剂/代谢肾/细胞学发光蛋白质类/遗传学膜流动性/药物作用膜流动性/生理学膜蛋白质类/代谢模型分子受体胆囊收缩素/代谢受体催产素/化学受体催产素/遗传学受体催产素/代谢重组蛋白质类/化学重组蛋白质类/代谢甾类/药理学转染人类

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Mitonmycin C对小鼠腹水肝癌细胞膜脂的作用

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中国医科大学学报 1988年第3期 178-181页

作者：朱明晏

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EFFECTS OF LIPID-PHASE SEPARATION ON THE FILIPIN ACTION ON MEMBRANES OF ERGOSTEROL-REPLACED TETRAHYMENA CELLS, AS STUDIED BY FREEZE-FRACTURE ELECTRON-MICROSCOPY

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BIOCHIMICA ET BIOPHYSICA ACTA 1979年第2期550卷 269-278页

作者： SEKIYA, T KITAJIMA, Y NOZAWA, Y GIFU UNIV SCH MED DEPT BIOCHEM KAKAMIGAHARA GIFU 504 JAPAN

The effects of lipid-phase separation on the filipin action on pellicle membranes of ergosterol-replaced T. pyriformis cells were studied by freeze-fracture EM. The pellicle membranes with phase separations induced by chilling from ***. C (growth temperature) to lower temperatures (30, 22 and ***. C) were treated with filipin. This produced filipin-induced lesions (pits) only in the particulated (liquid) regions along the margin between solid and liquid domains, while they were produced in the particle-free (solid) areas when membranes were chilled to ***. C. The pellicle membranes with lesions induced by filipin at ***. C were chilled to ***. C. This chilling raised larger particle-free areas and more condensed particle-aggregations on those membranes with the filipin treatment. The membrane fluidity affects induction and development of the ergosterol-filipin complex in the membrane.

关键词：细胞膜/药物作用细胞膜/代谢细胞膜/超微结构麦角固醇/代谢非律平/药理学冷冻断裂膜流动性/药物作用膜脂质类/代谢显微镜检查电子聚烯类/药理学四膜虫梨形/药物作用动物

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辛伐他汀对冠心病患者血小板膜流动性及血小板粘附性的影响

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中国病理生理杂志 2002年第13期18卷 1694页

作者：舒娟吕卓人田刚耿涛陕西西安交通大学第一医院心内科 710061

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