Characterization of a stretch-activated potassium channel in chondrocytes.
Characterization of a stretch-activated potassium channel in chondrocytes.
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DOI：
10.1002/jcp.22075
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发表时间：
2010-05
影响因子：
5.6
通讯作者：
Barrett-Jolley, Richard
中科院分区：
文献类型：
--
作者：
Mobasheri, Ali;Lewis, Rebecca;Maxwell, Judith E. J.;Hill, Claire;Womack, Matthew;Barrett-Jolley, Richard
软骨细胞具有将负载引起的机械刺激转换成电化学信号的能力。本研究的目的是对分离的原代马软骨细胞中响应膜拉伸而激活的离子通道进行功能表征。我们使用膜片钳电生理学来功能表征该通道，并使用免疫组织化学来检查其在关节软骨中的分布。在细胞贴附贴片实验中，对贴片吸管施加负压（范围在 20-200mmHg）可激活七个贴片中六个的离子通道电流。膜电位为33mV（细胞表面积约240μm2）时，平均激活电流为45.9±1.1pA（n=≥4）。在总拉伸激活电流内解析的主要单通道的平均斜率电导为118±±19pS（n = 6），并在理论钾平衡电位EK+附近反转，表明它是高电导钾通道。这些高电导钾通道的激活被细胞外 TEA（Kd 约 900μM）和伊比利亚毒素（Kd 约 40nM）抑制。这表明电流主要由 BK 样钾 (MaxiK) 通道携带。为了进一步表征这些 BK 样通道，我们使用了由内而外的软骨细胞膜斑块：我们发现这些通道通过浴钙浓度的升高而被激活。使用 BK 通道 α1 和 β1 亚基的多克隆抗体对马软骨样本进行免疫组织化学染色，结果显示浅层软骨细胞中两个亚基均呈阳性免疫反应性。这些实验支持这样的假设：功能性 BK 通道存在于软骨细胞中，并且可能参与机械转导和化学转导。
Chondrocytes possess the capacity to transduce load-induced mechanical stimuli into electrochemical signals. The aim of this study was to functionally characterize an ion channel activated in response to membrane stretch in isolated primary equine chondrocytes. We used patch-clamp electrophysiology to functionally characterize this channel and immunohistochemistry to examine its distribution in articular cartilage. In cell-attached patch experiments, the application of negative pressures to the patch pipette (in the range of 20–200 mmHg) activated ion channel currents in six of seven patches. The mean activated current was 45.9 ± 1.1 pA (n = 4) at a membrane potential of 33 mV (cell surface area approximately 240 µm2). The mean slope conductance of the principal single channels resolved within the total stretch-activated current was 118 ± 19 pS (n = 6), and reversed near the theoretical potassium equilibrium potential, EK+, suggesting it was a high-conductance potassium channel. Activation of these high-conductance potassium channels was inhibited by extracellular TEA (Kd approx. 900 µM) and iberiotoxin (Kd approx. 40 nM). This suggests that the current was largely carried by BK-like potassium (MaxiK) channels. To further characterize these BK-like channels, we used inside-out patches of chondrocyte membrane: we found these channels to be activated by elevation in bath calcium concentration. Immunohistochemical staining of equine cartilage samples with polyclonal antibodies to the α1- and β1-subunits of the BK channel revealed positive immunoreactivity for both subunits in superficial zone chondrocytes. These experiments support the hypothesis that functional BK channels are present in chondrocytes and may be involved in mechanotransduction and chemotransduction.
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DOI：
10.1016/s1357-2725(02)00301-1
发表时间：
2003-04-01
影响因子：
4
作者：
Archer, CW;Francis-West, P
通讯作者：
Francis-West, P
影响因子：
2.4
作者：
Lippiat, JD;Standen, NB;Davies, NW
通讯作者：
Davies, NW
影响因子：
7
作者：
Mobasheri, A.;Gent, T. C.;Barrett-Jolley, R.
通讯作者：
Barrett-Jolley, R.
影响因子：
2.2
作者：
Knight, MM;Ghori, SA;Bader, DL
通讯作者：
Bader, DL
影响因子：
5.5
作者：
HODGKIN, AL;KATZ, B
通讯作者：
KATZ, B