Maxi K+ channel in apical membrane of vestibular dark cells.
Maxi K+ channel in apical membrane of vestibular dark cells.
复制标题
前庭暗细胞顶膜中的 Maxi K 通道。
DOI：
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发表时间：
1992
影响因子：
--
通讯作者：
P. Wangemann
中科院分区：
文献类型：
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作者：
S. Takeuchi;D. C. Marcus;P. Wangemann
记录从前庭暗细胞从半规管的沙鼠，以确定是否离子通道可能参与的过程中的K+分泌的顶膜补丁。两种非选择性阳离子通道[Am. J.Physiol.262（Cell Physiol.31）：C1430-C1436，1992]和K（+）-选择性通道。在对称的145 mM KCl溶液中，K（+）-选择性通道的电流-电压（I-V）关系为线性，表明不存在整流，电导为240 +/- 8 pS（n = 8）。在不对称的K+和Na+溶液中，K+单独携带电流的Goldman-Hodgkin-Katz方程可以拟合到I-V关系，得到K+渗透率为5.78 × 10 ~（-13）cm ~ 3/s（n = 12）。该通道被证明是不可渗透的Li+，NH 4+，N-甲基-D-葡糖胺，和Cl-。通道活性随着去极化和游离[Ca 2 +]的增加而增加;对于+40至-60 mV之间的电压，最强的调节发生在10（-6）至10（-5）M Ca 2+范围内。四乙基铵（2 × 10（-2）M）从胞质侧对开放概率（Po）没有影响，但从细胞外侧完全抑制活性。Ba 2+（5 × 10（-3）M）、维拉帕米（10（-4）M）、奎宁（10（-4）M）和奎尼丁（10（-4）和10（-3）M）可降低Po，而利多卡因（5 × 10（-3）M）对Po没有可测量的影响，但降低了振幅。Rb+和Cs+要么渗透性差，要么部分阻断通道的电压依赖性方式。（250字处删节）
Recordings were made on excised apical membrane patches from vestibular dark cells from the semicircular canal of gerbils to determine if ion channels could be involved in the process of K+ secretion. Both nonselective cation channels [Am. J. Physiol. 262 (Cell Physiol. 31): C1430-C1436, 1992] and K(+)-selective channels were found. The K+ channels occurred in only 0.7% of the patches. In symmetrical 145 mM KCl solutions, the current-voltage (I-V) relation of the K(+)-selective channel was linear, indicating the absence of rectification, and the conductance was 240 +/- 8 pS (n = 8). The Goldman-Hodgkin-Katz equation for current carried solely by K+ could be fitted to the I-V relation in asymmetrical K+ and Na+ solutions and yielded a K+ permeability of 5.78 x 10(-13) cm3/s (n = 12). The channel was shown to be impermeable to Li+, NH4+, N-methyl-D-glucamine, and Cl-. Channel activity increased with depolarization and with increasing free [Ca2+]; for voltages between +40 and -60 mV, the strongest regulation occurred in the range 10(-6) to 10(-5) M Ca2+. Tetraethylammonium (2 x 10(-2) M) had from the cytosolic side no effect on the open probability (Po) but completely inhibited activity from the extracellular side. Po was reduced by Ba2+ (5 x 10(-3) M), verapamil (10(-4) M), quinine (10(-4) M), and quinidine (10(-4) and 10(-3) M), while lidocaine (5 x 10(-3) M) had no measurable effect on Po but decreased the amplitude. Rb+ and Cs+ were either poorly permeable or partially blocked the channel in a voltage-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)
DOI：
10.1016/0304-4157(87)90003-7
发表时间：
1987
期刊：
Biochimica et biophysica acta
影响因子：
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作者：
Wills,NK;Zweifach,A
通讯作者：
Zweifach,A
沙鼠椭圆囊非感觉区对 Cl- 的跨上皮电反应。
DOI：
10.1016/0005-2736(89)90454-9
发表时间：
1989
期刊：
Biochimica et biophysica acta
影响因子：
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作者：
Marcus,DC;Marcus,NY
通讯作者：
Marcus,NY