MERCURY IN CHLORIDE TRANSPORT IN SHARK RECTAL GLAND & RABBIT THICK ASCENDING LIMB

鲨鱼直肠腺中氯化物转运中的汞

• 批准号: 6575672
• 负责人: PATRICIO SILVA
• 金额: $ 17.41万
• 依托单位: MOUNT DESERT ISLAND BIOLOGICAL LAB
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6575672
• 关键词: adenosinetriphosphatase; adenylate cyclase; cell membrane; chemical binding; chlorine; ion transport; laboratory rabbit; membrane transport proteins; mercury; mercury poisoning; potassium; protein kinase A; protein kinase C; renal tubule; salt gland; saltwater environment; sharks; tissue /cell culture; toxicant interaction; transport inhibitor

The intent of this proposal is to study the mechanism of action of the toxic effect of mercury on transport by chloride transporting epithelia. Mercury inhibits chloride transport in both the shark rectal gland and the mammalian thick ascending limb but its mechanism of action mechanism of action is unknown. In the proposed set of experiments we will study the effect of organic and inorganic mercury on the transport of chloride by the shark rectal gland and compare it with that in the thick ascending limb of the loop of Henle. The mechanism of the inhibition of mercury, mercurial (both inorganic and organic) or of any compound on chloride transport by the rectal gland or the thick ascending limb can be evaluated with reference to our present understanding of transport by these cells. Inhibitory effects are possible at five different sites: 1) The site of entry of chloride into the cell, the Na-K-2CI carrier; 2) Inhibition of Na-K-ATPase with the resulting reduction in the driving force for entry of sodium, chloride and potassium via the cotransporter; 3) Inhibition of cellular metabolism resulting in insufficient ATP to power the pump; 4) Inhibition of the exit of chloride at the apical membrane by a reduction in the apical membrane conductance for chloride; 5) inhibition of potassium recycling through the potassium conductive pathway. These possibilities can be distinguished using specific transport inhibitors in combination with mercury. An additive effect of mercurial to inhibit chloride transport in the presence of specific inhibitors of these transport steps will suggest a site of action of distinct from that of the specific inhibitor. Because we have found unexpected and striking differences in the response of these two epithelia to inorganic and organic mercurial, we believe that the comparative approach will be particularly fruitful. We will examine the mechanism and the cellular site of action of mercury by determining its effect in the isolated perfused rectal gland, isolated rectal gland tubules, rectal gland membrane vesicles, rectal gland plasma membranes, thick ascending limb cells, thick ascending limb vesicles, thick ascending limb plasma membranes. Specifically we will examine the binding of mercury by plasma membranes and cytosolic proteins; the effect of mercury on the chloride cotransporter, the efflux of potassium, the chloride conductance, and its effect on transport related enzymes.

该提议的目的是研究 汞对氯化物运输上皮的运输的毒性作用。 汞抑制鲨鱼直肠腺和 哺乳动物厚的肢体，但其作用机理机理 行动是未知的。 在提议的一组实验中，我们将研究 有机和无机汞对氯化物的运输的影响 通过鲨鱼直肠腺并将其与厚升的 亨尔循环的肢体。 抑制汞，汞的机制（无机和 有机）或直肠腺上氯化物传输的任何化合物或 可以参考我们的现在评估较厚的上升肢 了解这些细胞的运输。 抑制作用是 可能在五个不同的地点：1）氯化物进入地点 细胞，NA-K-2CI载体； 2）抑制Na-k-ATPase 导致钠，氯化物进入的驱动力降低 和钾通过共转运蛋白； 3）抑制细胞代谢 导致ATP不足以为泵供电； 4）抑制 氯化物在根尖膜上的出口通过减少顶点 氯化物的膜电导； 5）抑制钾回收 通过钾导电途径。 这些可能性可能是 结合使用特定的运输抑制剂区分 汞。 汞对抑制氯化物转运的添加作用 在存在这些运输步骤的特定抑制剂的情况下 建议一个与特定抑制剂不同的作用部位。 因为我们发现响应中的意外差异 在这两个上皮和无机和有机汞中 比较方法将特别富有成果。 我们将 检查汞的机理和细胞作用位点 确定其在孤立的灌注直肠腺中的作用，分离 直肠腺小管，直肠腺膜囊泡，直肠腺等离子体 膜，较厚的肢体细胞，较厚的肢体囊泡， 较厚的肢体质膜。 具体而言，我们将检查 质膜和胞质蛋白通过汞结合；效果 汞在氯离子旋转剂，钾外排的of of 氯化物电导及其对相关酶的影响。