在醋酸盐培养基中孵育的兔肾皮质切片中的钠-氢离子交换

Sodium-hydrogen ion exchange in rabbit renal cortical slices incubated in acetate media.

作者信息

Macknight A D, McLaughlin C W, Scott R J

机构信息

Department of Physiology, University of Otago Medical School, Dunedin, New Zealand.

出版信息

J Physiol. 1988 Apr;398:523-41. doi: 10.1113/jphysiol.1988.sp017055.

DOI:10.1113/jphysiol.1988.sp017055

PMID:2839675

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1191785/

Abstract

Thin slices (0.2-0.3 mm) of rabbit renal cortex have been incubated in isosmotic oxygenated acetate media at 25 degrees C with or without ouabain (10(-3) M), amiloride (2 x 10(-3) M) or iodoacetamide (10(-3) M). 2. Slices in normal isosmotic 146 mM-sodium-132 mM-acetate media swelled as reported previously (Cooke & Macknight, 1984). This swelling was not prevented by amiloride or by metabolic inhibition. 3. Slices in isosmotic 132 mM-choline-132 mM-acetate media gained much less water and were little affected by ouabain, amiloride or metabolic inhibition. Choline was able to substitute neither for sodium nor for potassium in activating preparations of renal cortical Na+-K+-ATPase in chloride or in acetate media. 4. Slices in isosmotic 20 mM-sodium-132 mM-acetate medium swelled nearly as much as did slices in normal sodium acetate medium. However, this swelling was impaired markedly by amiloride, by ouabain and by metabolic inhibition. 5. There was a direct correlation between medium sodium concentration and slice water content as sodium was increased from 1.25 to 30 mM in 132 mM-acetate media. However, up to a sodium concentration of 10 mM, amiloride (2 x 10(-3) M) completely prevented this increase in water content. 6. Increasing medium amiloride concentration from 10(-5) to 10(-3) M progressively inhibited cellular swelling in 10 mM-sodium-132 mM-acetate medium. It is concluded that, under these experimental conditions, the dominant pathway for hydrogen ion extrusion from the cells was via amiloride-sensitive sodium-hydrogen exchange. 7. The results are discussed in terms of a model which explains cellular swelling in acetate media in terms of (a) non-ionic diffusion of acetic acid across plasma membranes impermeable to the acetate anion, (b) removal from the cells of the hydrogen ion gained with the acetate by amiloride-sensitive sodium-hydrogen counter-transport and (c) subsequent extrusion of sodium from the cell accompanied by potassium uptake via the ouabain-sensitive Na+-K+-ATPase. 8. The results provide evidence for ion movements across the luminal plasma membrane of proximal tubular cells in rabbit renal cortical slices.

摘要

将兔肾皮质的薄片（0.2 - 0.3毫米）在25摄氏度下于等渗充氧乙酸盐培养基中孵育，培养基中添加或不添加哇巴因（10⁻³ M）、氨氯吡咪（2×10⁻³ M）或碘乙酰胺（10⁻³ M）。2. 如先前报道（库克和麦克奈特，1984年），置于正常等渗的146 mM - 钠 - 132 mM - 乙酸盐培养基中的薄片会肿胀。氨氯吡咪或代谢抑制并不能阻止这种肿胀。3. 置于等渗的132 mM - 胆碱 - 132 mM - 乙酸盐培养基中的薄片吸水量少得多，且几乎不受哇巴因、氨氯吡咪或代谢抑制的影响。胆碱在氯化物或乙酸盐培养基中激活肾皮质钠 - 钾 - ATP酶制剂时，既不能替代钠也不能替代钾。4. 置于等渗的20 mM - 钠 - 132 mM - 乙酸盐培养基中的薄片肿胀程度几乎与置于正常乙酸钠培养基中的薄片相同。然而，这种肿胀明显受到氨氯吡咪、哇巴因和代谢抑制的损害。5. 在132 mM - 乙酸盐培养基中，随着钠浓度从1.25 mM增加到30 mM，培养基钠浓度与薄片含水量之间存在直接相关性。然而，在钠浓度达到10 mM之前，氨氯吡咪（2×10⁻³ M）完全阻止了含水量的这种增加。6. 在10 mM - 钠 - 132 mM - 乙酸盐培养基中，将培养基氨氯吡咪浓度从10⁻⁵ M增加到10⁻³ M可逐渐抑制细胞肿胀。得出的结论是，在这些实验条件下，细胞排出氢离子的主要途径是通过氨氯吡咪敏感的钠 - 氢交换。7. 根据一个模型对结果进行了讨论，该模型从以下方面解释了乙酸盐培养基中的细胞肿胀：(a) 乙酸通过质膜的非离子扩散，质膜对乙酸根阴离子不可渗透；(b) 通过氨氯吡咪敏感的钠 - 氢逆向转运从细胞中去除与乙酸结合获得的氢离子；(c) 随后细胞排出钠并通过哇巴因敏感的钠 - 钾 - ATP酶摄取钾。8. 这些结果为兔肾皮质切片近端肾小管细胞管腔质膜上的离子运动提供了证据。