Intracellular chloride activity in quiescent cat papillary muscle.
Intracellular chloride activity in quiescent cat papillary muscle.
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静止猫乳头肌中的细胞内氯离子活性。
DOI：
10.1152/ajpheart.1980.238.4.h487
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
J. L. Walker
中科院分区：
文献类型：
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作者：
K. Spitzer;J. L. Walker
使用氯化物液体离子交换剂微电极测量静止猫乳头肌中的细胞内氯化物活性（α iCl）。将肌肉灌注在含有对照浓度的氯化物 (146.1 mM) 和 2.7、4.4 或 5.4 mM 钾的碳酸氢盐缓冲溶液中。所得平均膜电位分别为-96.2、-86.8和-80.6 mV。相比之下，α iCl 和氯化物平衡电位不会因外部钾的这些变化而改变，并且在从动物中取出组织后长达 10 小时内保持稳定在 11 mM 和 -60 mV。该 α iCl 值大约比假设氯离子被动分布时预测的值大 2-4 倍。细胞内干扰的上限根据外部氯化物灌注量低进行估算，结果发现不大于 2-3 mM。长时间暴露于用 N-2-羟乙基哌嗪-N'-2-乙磺酸 (HEPES) 缓冲的不含碳酸氢盐的溶液不会降低 α iCl 的表观值，表明细胞内碳酸氢盐的细胞内干扰不会显着影响 α iCl 的测量。这些结果表明，氯化物可以逆着电化学梯度进入猫乳头肌。
Intracellular chloride activity (alpha iCl) was measured in quiescent cat papillary muscles with chloride liquid ion-exchanger microelectrodes. Muscles were superfused in bicarbonate-buffered solutions containing a control concentration of chloride (146.1 mM) and either 2.7, 4.4, or 5.4 mM potassium. The resulting mean membrane potentials were -96.2, -86.8, and -80.6 mV, respectively. In contrast, alpha iCl and the chloride equilibrium potential were unchanged by these alterations in external potassium and remained stable at 11 mM and -60 mV for up to 10 h following removal of the tissue from the animal. This value of alpha iCl is approximately 2-4 times greater than that predicted assuming chloride is passively distributed. The upper limit of intracellular interference was estimated from low external chloride superfusion and found to be no greater than 2-3 mM. Prolonged exposure to bicarbonate-free solutions buffered with N-2-hydroxyethyl piperazine-N'-2-ethanesulfonic acid (HEPES) did not reduce the apparent value of alpha iCl, suggesting that intracellular interference from intracellular bicarbonate does not significantly influence the measurement of alpha iCl. These results suggest that chloride can move into cat papillary muscle against an electrochemical gradient.