Cellular pH and Na+-H+ exchange activity in lens epithelium of Bufo marinus toad.
Cellular pH and Na+-H+ exchange activity in lens epithelium of Bufo marinus toad.
复制标题
蟾蜍晶状体上皮的细胞 pH 值和 Na -H 交换活性。
DOI：
10.1152/ajpcell.1988.255.5.c595
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Candia,OA
中科院分区：
文献类型：
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作者：
Wolosin,JM;Alvarez,LJ;Candia,OA
将晶状体与2，7-二羧乙基-5（6）-羧基荧光素的乙酰氧基甲酯（BCECF-AM）一起孵育，导致脱酯化的、pH敏感的、膜不可渗透形式的染料（BCECF）在透镜上皮细胞中的选择性、延长的截留，从而允许对完整晶状体中的上皮细胞内pH（pHi）进行连续荧光监测。在生理溶液中的厌氧条件下，上皮细胞保持7.36 +/- 0.14的pHi（平均值+/- SD，n = 6枚晶状体）。在不存在CO2和HCO 3-的情况下，pHi增加到7.83 +/- 0.38（n = 55）。在此条件下，无论是去除Na+或添加阿米洛利的介质中导致的pH值下降。当晶状体在细胞外Na+去除之前加载Na+时，这种酸化以阿米洛利可降解的方式增加。人工产生的细胞酸中毒的程度（诱导的“NH 4+加载”技术）显着降低细胞外Na+的存在下，或恢复其添加时，最初的离子是不存在的;后者的逆转抑制阿米洛利。这种抑制作用被莫能菌素的加入所绕过。结论上皮细胞中存在Na+-H+反向转运。
Incubation of lenses with the acetoxymethyl ester of 2,7-biscarboxyethyl-5(6)-carboxyfluorescein (BCECF-AM) led to selective, prolonged entrapment of the deesterified, pH-sensitive, membrane-impermeable form of the dye (BCECF) in the lens epithelial cells allowing, thereby, for the continuous fluorometric monitoring of epithelial intracellular pH (pHi) in intact lenses. Under anaerobic conditions in physiological solution, the epithelium maintained a pHi of 7.36 +/- 0.14 (mean +/- SD, n = 6 lenses). In the absence of CO2 and HCO3-, the pHi increased to 7.83 +/- 0.38 (n = 55). In this condition, either the removal of Na+ or the addition of amiloride to the medium resulted in a decrease of pHi. This acidification was increased in amiloride-inhibitable fashion when lenses were loaded with Na+ before extracellular Na+ removal. The extent of artificially generated cellular acidosis (induced by the "NH4+ loading" technique) was markedly decreased by the presence of extracellular Na+ or reverted on its addition when the ion was initially absent; the latter reversal was inhibited by amiloride. This inhibition was by-passed by monensin addition. The existence of a Na+-H+ antiport in the epithelial cells is concluded.