Radioautographic localization of sodium pump sites in rabbit intestine.
Radioautographic localization of sodium pump sites in rabbit intestine.
复制标题
兔肠道钠泵部位的放射性摄影定位。
DOI：
10.1083/jcb.53.3.704
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发表时间：
1972-06
影响因子：
7.8
通讯作者：
Stirling, C E
中科院分区：
文献类型：
--
作者：
Stirling, C E
直接证明钠泵的细胞定位构成了解决肠钠吸收的关键问题。利用锇固定的冻干组织的硅树脂浸渍环氧切片，制备了哇巴因-3H和菊粉-3H的光镜放射自显影，结果表明：兔小肠的侧膜而非刷状缘膜与哇巴因-3H结合（高比活性），亲和力如此之大，以至于随后在不含哇巴因的培养基中洗涤对结合几乎没有影响;侧膜结合对于低比活性哇巴因-3H不明显，并且绒毛核心中的菊粉-3H和哇巴因-3H（低比活性）不与细胞间隙平衡。哇巴因-3H和菊糖-14C空间的初步示踪测量也与这些发现一致。由于哇巴因是主动钠转运的特异性抑制剂，这些观察结果为以下观点提供了直接支持：通过对水的渗透力，将钠泵入细胞间隙导致流体从这些空间流出进入细胞间隙。
Direct demonstration of the cellular location of sodium pumping constitutes a key problem in the solution of intestinal sodium absorption. Utilizing silicone-impregnated epoxy sections of freeze-dried, osmium-fixed tissue, ouabain-3H and inulin-3H light microscope radioautographs have been produced which show that: lateral but not brush border membranes of rabbit small intestine bind ouabain-3H (high specific activity) with an affinity so great that a subsequent washing in ouabain-free medium has little effect on binding; lateral membrane binding is not apparent with low specific activity ouabain-3H, and inulin-3H and ouabain-3H (low specific activity) in the cores of the villi do not equilibrate with the intercellular spaces. Preliminary tracer measurements of ouabain-3H and inulin-14C spaces also agree with these findings As ouabain is a specific inhibitor of active sodium transport, these observations provide direct support for the view that lateral membrane pumping of sodium into the intercellular spaces causes, through osmotic forces on water, a flow of fluid out of these spaces into the interstitium.