IDENTIFICATION OF ANION AND CATION PATHWAYS IN THE INNER MITOCHONDRIAL-MEMBRANE BY PATCH CLAMPING OF MOUSE-LIVER MITOPLASTS
IDENTIFICATION OF ANION AND CATION PATHWAYS IN THE INNER MITOCHONDRIAL-MEMBRANE BY PATCH CLAMPING OF MOUSE-LIVER MITOPLASTS
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DOI：
10.1007/bf01870459
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发表时间：
1991-11-01
影响因子：
2.4
通讯作者：
TEDESCHI, H
中科院分区：
文献类型：
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作者：
ANTONENKO, YN;KINNALLY, KW;TEDESCHI, H
用膜片钳技术测量，pH从6.8到8.3使线粒体内膜基质侧碱化导致+/-40 mV电流可逆性增加3.2+/-0.2pA(平均值+/-SE，n=21)。目前的增加被添加的镁离子和降低的pH以分级的方式逆转。在0.5、1和2M KCl处进行单通道事件的检测。0.15M KCl中的单通道幅度大约相当于15ps。全膜片电流的翻转电位表明，线粒体膜在pH为6.8时以阳离子选择性为主，P(K)/P(Cl)=32(n=6)。碱性pH(8.3)处理增加了电流和阴离子通透性(P(K)/P(Cl)=16，n=6)。当加入低浓度(12-mU-M)的普萘洛尔时，膜变得完全阳离子选择性。两亲性药物胺碘酮(4-mU-M)、心得安(70-mU-M)和奎宁(0.6 mM)几乎阻断了所有的电流。三丁基锡也能抑制该pH依赖性电流。这些结果与线粒体膜内存在两条通路相一致。一种是阳离子选择性，一般开放；另一种是阴离子选择性，由碱性pH诱导。碱性pH激活通道可能对应于其他人从悬浮研究中推测的内膜阴离子通道。
Alkalinization of the matrix side of the mitochondrial inner membrane by pH shifts from 6.8 to 8.3 caused a reversible increase in current of 3.2 +/- 0.2 pA (mean +/- SE, n = 21) at +/- 40 mV measured using patch-clamp techniques. The current increase was reversed in a graded fashion by the addition of Mg2+ as well as a reduction in pH. Detection of single-channel events was done at 0.5, 1 and 2 M KCl. The single-channel amplitude in 0.15 M KCl corresponds to approximately 15 pS. Reversal potentials derived from whole patch currents indicated that the inner mitochondrial membrane was primarily cation selective at pH 6.8 with a P(K)/P(Cl) = 32 (n = 6). Treatment with alkaline pH (8.3) increased the current and anion permeability (P(K)/P(Cl) = 16, n = 6). The membrane becomes completely cation selective when low concentrations (12-mu-M) of the drug propranolol are added. The amphiphilic drugs amiodarone (4-mu-M), propranolol (70-mu-M) and quinine (0.6 mM) blocked almost all of the current. The pH-dependent current was also inhibited by tributyltin. These results are consistent with the presence of two pathways in the inner mitochondrial membrane. One is cation selective and generally open and the other is anion selective and induced by alkaline pH. The alkaline pH-activated channel likely corresponds to the inner membrane anion channel postulated by others from suspension studies.