Cuthbert A W, Shum W K
J Membr Biol. 1978;40 Spec No:221-45. doi: 10.1007/BF02026008.
Specific binding of 14C-amiloride to the mucosal surface of frog skin epithelium (Rana temporaria) has been used as a measure of the number of sodium entry sites. All binding measurements were made with the mucosal surface bathed in a solution containing 1.1 mM sodium. When manipulations were used which increased the intracellular concentration of sodium the amount of amiloride bound was reduced. The manipulations included flushing the mucosal surface with solutions containing 111 mM sodium after serosal efflux was inhibited with ouabain or potassium removal. Similar results were obtained when cells were loaded with lithium. These effects on amiloride binding did not appear to depend on changes in membrane potential or upon changes in affinity of amiloride for its binding site. It appears that inhibition of serosal sodium efflux from the epithelium causes a reduction of mucosal sodium influx by making entry sites unavailable. This latter may be a result, directly or indirectly, of the sodium concentration in the sodium transport pool.
利用14C-氨氯吡脒与蛙皮上皮（林蛙）黏膜表面的特异性结合来衡量钠进入位点的数量。所有结合测量均在黏膜表面浸浴于含1.1 mM钠的溶液中进行。当采用增加细胞内钠浓度的操作时，氨氯吡脒的结合量会减少。这些操作包括在用哇巴因抑制浆膜外流或去除钾后，用含111 mM钠的溶液冲洗黏膜表面。当细胞用锂加载时也获得了类似结果。这些对氨氯吡脒结合的影响似乎不取决于膜电位的变化或氨氯吡脒对其结合位点亲和力的变化。似乎上皮细胞浆膜钠外流的抑制通过使进入位点不可用而导致黏膜钠内流减少。后者可能直接或间接地是钠转运池中钠浓度的结果。
