Identification of a non-selective cation channel current in myometrial cells isolated from pregnant rats
Identification of a non-selective cation channel current in myometrial cells isolated from pregnant rats
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DOI：
10.1007/s00424-003-1175-z
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发表时间：
2004-01-01
影响因子：
4.5
通讯作者：
Ohama, K
中科院分区：
文献类型：
--
作者：
Miyoshi, H;Yamaoka, K;Ohama, K
非选择性阳离子通道（NSCC）电流的鉴定从妊娠大鼠（18-20天）分离的子宫肌层平滑肌细胞使用全细胞膜片钳方法。NSCC电流具有线性电流/电压关系，并且与时间无关。细胞外Na+的减少实质上降低了NSCC电流的幅度，表明NSCC对Na+是可渗透的。NSCC电流被La ~（3+）和Gd ~（3+）阻断，Kd值分别为2.2和1.0 μ M。通过测量反转电位来估计各种单价阳离子对NSCC的相对渗透性。K+：Cs+：Na+：Li+的相对渗透率为1.3：1：0.9：0.8。NSCC也有一个小的，但可检测到的Ca 2+渗透性。细胞外Mg ~（2+）浓度依赖性地抑制子宫肌层NSCC电流，Kd值为0.28 mM，这可能是Mg ~（2+）抑制子宫收缩治疗早产的机制之一。我们的研究结果表明，NSCC在调节子宫肌层收缩性中起作用。
Non-selective cation channel (NSCC) currents were identified in myometrial smooth muscle cells isolated from pregnant rats (day 18-20) using the whole-cell patch clamp method. NSCC currents had a linear current/voltage relationship and were time independent. Reduction of extracellular Na+ substantially decreased the amplitude of NSCC currents, indicating that the NSCC is permeable to Na+. NSCC currents were blocked by La3+ and Gd3+ with K-d values of 2.2 and 1.0 muM, respectively. The relative permeability of various monovalent cations for NSCC was estimated by measurement of the reversal potential. The relative permeability for K+:Cs+:Na+:Li+ was 1.3:1:0.9:0.8. NSCC also had a small, but detectable, permeability for Ca2+. Extracellular Mg2+ inhibited myometrial NSCC currents concentration dependently with a K-d of 0.28 mM. The observed Mg2+ block may reasonably explain the inhibitory effect of magnesium on uterine contractions in the treatment of pre-term labor. Our results suggest that the NSCC plays a role in the regulation of myometrial contractility.