Surface potentials and sodium entry in frog skin epithelium.
Surface potentials and sodium entry in frog skin epithelium.
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DOI：
10.1113/jphysiol.1981.sp013977
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发表时间：
1981-12
期刊：
影响因子：
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通讯作者：
D. Benos;R. Latorre;J. Reyes
中科院分区：
文献类型：
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作者：
D. Benos;R. Latorre;J. Reyes
1.研究了离体牛蛙皮肤顶膜表面电位的改变对钠离子内流的影响。2.外部离子强度的变化对蛙皮肤上皮细胞的Na转运速率几乎没有影响。3.铀酰离子（UO 2（2+），2.5 mM）诱导磷脂酰丝氨酸单分子膜的表面电位发生+145 mV的变化，并诱导磷脂酰胆碱单分子膜的表面电位发生+60 mV的变化。4. UO 2（2+）抑制R中的短路电流（Isc）最多20%。catesbeiana皮肤，而刺激40%的R.颞叶皮肤在存在10（-4）M‐amiloride的情况下，UO 2（2+）既不能刺激Isc，也不能抑制Isc。5.从上面的第1点和第2点，我们得出结论，位于顶膜的Na选择性进入位点附近的表面电荷密度很小（大于1 e-/600 A2）。使用UO 2（2+）获得的结果表明，钠离子进入不受膜表面电位变化的影响。
1. The effects which alterations in the surface potential of the apical membrane of isolated Rana catesbeiana skin have on Na entry were examined. 2. Changes in the external ionic strength have little effect upon the rate of Na transport across the frog skin epithelium. 3. Uranyl ion (UO2(2+), 2.5 mM) induces a +145 mV change in the surface potential of phosphatidylserine monolayers, and a +60mV change in the surface potential of monolayers made from phosphatidylcholine. 4. UO2(2+) inhibits the short‐circuit current (Isc) by a maximum of 20% in R. catesbeiana skin, while stimulating Isc by 40% in R. temporaria skin. Neither Isc stimulation nor inhibition by UO2(2+) can be seen in the presence of 10(‐4) M‐amiloride. 5. From points 1 and 2 above, we conclude that the surface charge density in the neighbourhood of the Na‐selective entry site located in the apical membrane is small (greater than 1e‐/600 A2). The results obtained using UO2(2+) suggest that Na entry is not affected by changes in the membrane surface potential.