An investigation of chloride‐bicarbonate exchange in the sheep cardiac Purkinje fibre.
An investigation of chloride‐bicarbonate exchange in the sheep cardiac Purkinje fibre.
复制标题
羊心脏浦肯野纤维中氯化物-碳酸氢盐交换的研究。
DOI：
10.1113/jphysiol.1986.sp016259
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
R. Vaughan
中科院分区：
文献类型：
--
作者：
R. Vaughan
使用液体离子交换剂Cl选择性微电极和玻璃凹尖pH选择性微电极测量了分离的绵羊心脏浦肯野纤维的细胞内Cl活性（aiCl）和细胞内pH（pHi）。去除外部Cl（葡萄糖醛酸取代）使aiCl从约20降至约4 mmol/l：残留水平可能是由Cl敏感电极上的细胞内干扰引起的。在稳定状态下，将纤维重新暴露于增加的外部Cl水平会产生增加的aiCl水平。稳态aiCl对外部Cl活度aoCl的依赖性大致为双曲线，aoCl约为9.5 mmol/l时，回收率为50%。在所有水平的外部Cl测试，Cl积累到一个水平远高于预测的被动电化学平衡。将贫Cl纤维暴露于不同水平的外部Cl中，aiCl随时间呈指数上升。据估计，aiCl的初始上升速率是aoCl的饱和函数，在aoCl约为33 mmol/l时出现半最大效应。上升速率比使用公布的Cl渗透系数PCl值从恒定场理论预测的上升速率高约10倍。如果在恒定的外部pH（pHo）条件下发生外部HCO 3浓度（[HCO 3]o）的变化，即当[HCO 3]o的降低伴随着CO2分压（PCO 2）的同时降低时，稳态aiCl基本上对这些变化不敏感。相反，如果PCO 2保持恒定，则[HCO 3]o的变化（从而产生pHo的变化）导致aiCl的反向变化。aiCl的这种变化也伴随着pHi的变化：当aiCl增加时，pHi降低，反之亦然。阴离子交换抑制剂DIDS（4，4-二异硫氰酸基二苯乙烯二磺酸）消除了[HCO 3]o和pH值变化对aiCl的影响（在恒定的PCO 2下）。此外，DIDS降低了pHo对pHi的影响。无Cl溶液中aiCl的下降和重新暴露于含Cl溶液后Cl的后续再吸收均因[HCO 3]o的降低而减慢（恒定pH值，减少PCO 2）。Cl的再摄取和洗脱都是[HCO 3]o的饱和功能，半最大效应发生在[HCO 3]o为1 - 1.3 mmol/l时。Cl的再吸收几乎不受去除外部Na（双，2-羟乙基，二甲基铵取代）的影响。氯的再摄取不受阿米洛利（1 mmol/l）的影响，但减慢了piretanide（1 mmol/l）。（400字处截断摘要）
Intracellular Cl activity (aiCl), and intracellular pH (pHi) were measured in isolated sheep cardiac Purkinje fibres using a liquid ion exchanger Cl‐selective micro‐electrode and a glass recessed‐tip, pH‐selective micro‐electrode. Removal of external Cl (glucuronate substituted) produced a fall in aiCl from about 20 to about 4 mmol/l: the residual level is probably caused by intracellular interference on the Cl‐sensitive electrode. Re‐exposure of the fibre to increased levels of external Cl produced, in the steady state, increased levels of aiCl. The dependence of steady‐state aiCl upon external Cl activity, aoCl, was roughly hyperbolic with 50% recovery occurring at an aoCl of about 9.5 mmol/l. At all levels of external Cl tested, Cl was accumulated to a level much higher than that predicted for passive electrochemical equilibrium. Exposure of a Cl‐depleted fibre to various levels of external Cl produced an exponential rise with time in aiCl. The initial rate‐of‐rise in aiCl was estimated to be a saturating function of aoCl, with a half‐maximal effect occurring at an aoCl of about 33 mmol/l. The rate‐of‐rise was about 10‐fold greater than that predicted from constant‐field theory using published values for PCl, the Cl permeability coefficient. Steady‐state aiCl was essentially insensitive to changes in external HCO3 concentration, [HCO3]o, if these changes were made at a constant external pH, pHo, i.e. when a reduction in [HCO3]o was accompanied by a simultaneous reduction in the partial pressure of CO2, PCO2. In contrast, if PCO2 was maintained constant, then a change in [HCO3]o (thus producing a change in pHo) resulted in an inverse change in aiCl. This change in aiCl was also accompanied by a change in pHi: when aiCl increased, pHi decreased and vice versa. The anion‐exchange inhibitor, DIDS (4,4‐diisothiocyanato‐stilbene disulphonic acid) abolished the effect on aiCl of changes in [HCO3]o and pHo (at constant PCO2). Furthermore DIDS reduced the influence of pHo upon pHi. Both the fall of aiCl in Cl‐free solution and the subsequent reuptake of Cl following re‐exposure to Cl‐containing solution were slowed by a reduction in [HCO3]o (constant pHo, reduced PCO2). Both reuptake and wash‐out of Cl were saturating functions of [HCO3]o with half‐maximal effect occurring at an [HCO3]o of 1‐1.3 mmol/l. The reuptake of Cl was little affected by removal of external Na (bis,2‐hydroxy ethyl, dimethyl ammonium substituted). The reuptake of Cl was unaffected by amiloride (1 mmol/l) but slowed by piretanide (1 mmol/l).(ABSTRACT TRUNCATED AT 400 WORDS)
培养鸡心脏细胞中的钾-氯化物共转运。
DOI：
10.1152/ajpcell.1985.249.3.c337
发表时间：
1985
期刊：
The American journal of physiology
影响因子：
--
作者：
Piwnica-Worms,D;Jacob,R;Horres,CR;Lieberman,M
通讯作者：
Lieberman,M