Passive K+-Cl- fluxes in low-K+ sheep erythrocytes: modulation by A23187 and bivalent cations.
Passive K+-Cl- fluxes in low-K+ sheep erythrocytes: modulation by A23187 and bivalent cations.
复制标题
低 K 绵羊红细胞中的被动 K -Cl - 通量：A23187 和二价阳离子的调节。
DOI：
10.1152/ajpcell.1985.249.3.c271
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Lauf,PK
中科院分区：
文献类型：
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作者：
Lauf,PK
低K+（LK）绵羊红细胞的哇巴因抗性（OR）K+通量的一部分是Cl-依赖性的（K+-Cl-转运），并通过细胞肿胀可逆激活或通过N-乙基马来酰亚胺（NEM）处理不可逆激活。研究了离子载体A23187加二价阳离子（Me 2+）或乙二醇-双（β-氨基乙基醚）-N，N '-四乙酸（EGTA）对对照或NEM处理的LK细胞中K+-Cl-转运的影响。提出了以下意见。1)A23187（6 μ M），在10%（体积/体积）的红细胞压积和1 mM EGTA的存在下，激活几倍OR K+-Cl-运输在萎缩或肿胀的细胞，但未能刺激进一步的K+-Cl-通量在NEM处理的细胞。2)在没有EGTA的情况下，但在非常低的外部Ca 2+浓度[（Ca 2+）0 = 10（-7）M）下，A23187在对照组中刺激OR K+-Cl-通量小于EGTA，并且在NEM处理的细胞中轻微抑制OR K+-Cl-通量。3)当[Ca ~（2+）]o升高到10（-3）M时，在皱缩、肿胀或NEM处理的细胞中，OR K ~+-Cl ~-通量几乎完全受到抑制。4)其他Me 2+抑制OR K+-Cl-通量在A23187的存在下，按以下顺序降低效力：Mn 2+比Ca 2+大得多比Mg 2+大得多比Sr 2+大得多比Ba 2+。5)A23187 +/- EGTA对OR K ~+-Cl ~-流的刺激和A23187 + Ca ~（2+）对OR K ~+-Cl ~-流的抑制是可逆的，且不显著改变细胞ATP。6)A23187加EGTA的刺激作用，可能是通过Me 2+去除，对K+-Cl-通量和其抑制Ca 2+可逆地取消在代谢耗尽的细胞。（250字处删节）
A fraction of the ouabain-resistant (OR) K+ flux of low-K+ (LK) sheep erythrocytes is Cl- dependent (K+-Cl- transport) and is activated reversibly by cell swelling or irreversibly by treatment with N-ethylmaleimide (NEM). The effect of the ionophore A23187 plus bivalent cations (Me2+) or ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA) was studied on K+-Cl- transport in control or NEM-treated LK cells. The following observations were made. 1) A23187 (6 microM), at a hematocrit of 10% (vol/vol) and in the presence of 1 mM EGTA, activated severalfold OR K+-Cl- transport in shrunken or swollen cells but failed to stimulate further K+-Cl- flux in NEM-treated cells. 2) In the absence of EGTA, but at very low external Ca2+ concentrations [( Ca2+]o = 10(-7) M), A23187 stimulated OR K+-Cl- flux in controls less than with EGTA and inhibited it slightly in NEM-treated cells. 3) When [Ca2+]o was raised to 10(-3) M, an almost complete inhibition of OR K+-Cl- fluxes occurred in shrunken, swollen, or NEM-treated cells. 4) Other Me2+ inhibited OR K+-Cl- flux in the presence of A23187 in the following order of decreasing potency: Mn2+ much greater than Ca2+ greater than Mg2+ greater than Sr2+ much much greater than Ba2+. 5) Stimulation of OR K+-Cl- flux by A23187 +/- EGTA and inhibition by A23187 + Ca2+ were reversible and did not alter significantly cellular ATP. 6) The stimulatory effect of A23187 plus EGTA, perhaps by Me2+ removal, on K+-Cl- flux and its inhibition by Ca2+ were reversibly abolished in metabolically depleted cells.(ABSTRACT TRUNCATED AT 250 WORDS)