Cyclic AMP stimulation of Cl- secretion by the opercular epithelium: the basolateral chloride uptake mechanism.
Cyclic AMP stimulation of Cl- secretion by the opercular epithelium: the basolateral chloride uptake mechanism.
复制标题
环 AMP 刺激岛盖上皮分泌 Cl-：基底外侧氯摄取机制。
DOI：
10.1002/jez.1402400204
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
K. Degnan
中科院分区：
文献类型：
--
作者：
K. Degnan
分离的、短路的异地沟盖上皮细胞，通过依赖于浆膜Na+的存在和布美他尼和速尿抑制的机制来分泌氯离子。在浆膜无Na+的条件下，活跃的Cl-分泌被取消。然而，随后用异丙肾上腺素或Forsklin升高细胞内环磷酸腺苷(CAMP)水平可显著刺激氯离子的分泌。这种刺激不受SITS、DDS、甲唑胺和无HCO-3溶液的影响，但可被速尿和布美他尼阻断。对细胞内相对~(36)Cl-浓度的测定表明，异丙肾上腺素刺激的内皮细胞内~(36)Cl~-依赖于Na~+，异丙肾上腺素刺激的细胞内~(36)Cl~-不依赖于Na~+。在这两种条件下，胞内36Cl-对布美他尼都是敏感的。结果表明，cAMP对Cl-分泌的刺激作用可能是通过一种Na+非依赖性的环状利尿剂抑制机制发生的，这种机制即使在Na+存在的情况下也可能是有效的。这是一种单独的氯离子摄取机制，还是cAMP引起的正常钠依赖机制的改变尚不能确定。在这两种情况下，都需要一种替代Na+梯度的方法，作为跨基底侧膜向细胞摄取氯离子的能量来源。
The isolated, short-circuited opercular epithelium of Fundulus heteroclitus, secretes Cl- by a mechanism dependent on the presence of serosal Na+ and inhibited by bumetanide and furosemide. Under serosal Na+-free conditions the active Cl- secretion is abolished. However, subsequent elevations of intracellular cyclic AMP (cAMP) levels with isoproterenol or forskolin stimulated Cl- secretion markedly. This stimulation was unaffected by SITS, DIDS, methazolamide, and HCO-3-free solutions, but was blocked by furosemide and bumetanide. Determinations of relative intracellular 36Cl- levels showed a Na+ dependence of intracellular 36Cl- in epithelia not stimulated by isoproterenol and a Na+ independence of intracellular 36Cl- in isoproterenol stimulated epithelia. In both conditions, the intracellular 36Cl- was bumetanide sensitive. The results indicate that cAMP stimulation of Cl- secretion can occur by a Na+-independent, loop diuretic-inhibitable mechanism, which may be operative even in the presence of Na+. Whether this is a separate Cl- uptake mechanism or a cAMP-induced alteration in the normal Na+-dependent mechanism could not be determined. In either instance, an alternative to the Na+ gradient as a source of energy for Cl- uptake into the cell across the basolateral membrane is required.