pHi dependence of Na-H exchange and H delivery in IEC-6 cells.
pHi dependence of Na-H exchange and H delivery in IEC-6 cells.
复制标题
IEC-6 细胞中 Na-H 交换和 H 输送的 pHi 依赖性。
DOI：
10.1152/ajpcell.1992.262.1.c164
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Machen,TE
中科院分区：
文献类型：
--
作者：
Sjaastad,MD;Wenzl,E;Machen,TE
Na-H交换器和未鉴定的酸加载过程的细胞内pH（pHi）依赖性用pH敏感染料2 ′，7 ′-双（2 ′，7 ′-bis）的显微荧光测定法测定了IEC-6（一种大鼠肠隐窝细胞系）中的pH释放（“H释放”）。（羧乙基）-5，6-羧基荧光素对生长在玻璃盖片上的细胞组的影响，玻璃盖片安装在无HCO 3溶液中的灌注室中（对NaCl-HCO 3交换和Na-HCO 3共转运）。使用两种方法测量Na-H交换和H递送速率。1)用NH 4Cl对细胞进行酸加载，并且在恢复期间的不同时间在添加阿米洛利之前和之后测量pHi恢复和酸化的速率。pHi恢复速率乘以固有缓冲容量（β i）得到净H流出速率，pHi降低速率（在阿米洛利治疗期间）乘以β i得到H递送速率，Na-H交换等于净H流出加上H递送。2)在对照细胞中，通过计算机对阿米洛利诱导的pHi降低（从7.36至6.65）和阿米洛利去除后pHi恢复（从6.65至7.49）的时间过程进行曲线拟合;计算pHi降低和恢复的速率;然后计算如上所述的不同pHi下的H输送、净H流出和Na-H交换。H传递和Na-H交换都是pHi依赖的，但方向相反。H递送在对照pHi下为2-7 mM/min，在pHi 6.6附近降至零。在对照pHi下Na-H交换也等于2-7 mM/min，并且这随着pHi降低而增加;在pHi 6.6下，Na-H交换为20-35 mM/min。（250字处删节）
The intracellular pH (pHi) dependencies of the Na-H exchanger and also of unidentified acid-loading processes (“H delivery”) in IEC-6, a rat intestinal crypt cell line, were determined using microspectrofluorimetry of the pH-sensitive dye 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein on groups of cells grown on glass cover slips mounted in a perfusion chamber in HCO3-free solutions (to inactivate Cl-HCO3 exchange and Na-HCO3 cotransport). Na-H exchange and H delivery rates were measured using two methods. 1) Cells were acid loaded with NH4Cl, and rates of pHi recovery and acidification were measured just before and then just after adding amiloride at various times during the recovery. Multiplying rates of pHi recovery times the intrinsic buffer capacity (beta i) yielded net H efflux rates, rates of pHi decrease (during amiloride treatment) times beta i yielded H delivery rates, and Na-H exchange equals net H efflux plus H delivery. 2) In control cells, time courses of amiloride-induced pHi decreases (from 7.36 to 6.65) and of pHi recovery following amiloride removal (from 6.65 to 7.49) were curve fit by computer; rates of pHi decrease and recovery were calculated; and H delivery, net H efflux, and Na-H exchange were then calculated at the different pHi as above. H delivery and Na-H exchange were both pHi dependent, but in the opposite directions. H delivery was 2-7 mM/min at the control pHi, decreasing to zero around pHi 6.6. Na-H exchange was also equal to 2-7 mM/min at the control pHi, and this increased as pHi decreased; at pHi 6.6, Na-H exchange was 20-35 mM/min.(ABSTRACT TRUNCATED AT 250 WORDS)