SMALL TRANSEPITHELIAL OSMOTIC GRADIENTS AFFECT APICAL SODIUM PERMEABILITY IN FROG-SKIN

被引:10
作者
BRODIN, B
NIELSEN, R
机构
[1] Laboratory of Biological Chemistry A, August Krogh Institute, University of Copenhagen, Copenhagen, DK-2100
来源
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY | 1993年 / 423卷 / 5-6期
关键词
RANA-TEMPORARIA; SODIUM CHANNEL; OSMOLARITY; MICROELECTRODE; OSMOTIC RECEPTOR; DIMETHYLSULFOXIDE;
D O I
10.1007/BF00374935
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
The aim of the present study was to investigate the effects of small, unilateral changes in solution osmolarity on active sodium transport and cellular electrophysiological parameters in frog skin. The active sodium transport across the skin was measured as the amiloride-sensitive short-circuit current (I(sc)) and cellular potential was monitored with microelectrodes, while small (+/- 20 mOsm) osmotic gradients were imposed on the skin. Increasing the osmolarity of the apical bathing solution (or decreasing the osmolarity of the basolateral solution) increased I(SC), lowered tissue resistance (R), depolarized the cellular potential and decreased the fractional resistance of the apical membrane, which indicates an increased apical sodium permeability. Conversely, a similar increase in basolateral osmolarity (or a decrease in apical osmolarity) lowered the I(sc), increased R, hyperpolarized the cells and increased the fractional resistance of the apical membrane, indicating a decrease in apical sodium permeability. The results indicate that the osmotic gradient across the skin, rather than solution osmolarity as such, is responsible for the observed changes in I(sc) and apical sodium permeability after small osmotic perturbations.
引用
收藏
页码:411 / 417
页数:7
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