Differential regulation of Ca 2+-activated Cl- currents in rabbit arterial and portal vein smooth muscle cells by Ca2+-calmodulin-dependent kinase
Differential regulation of Ca 2+-activated Cl- currents in rabbit arterial and portal vein smooth muscle cells by Ca2+-calmodulin-dependent kinase
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DOI：
10.1111/j.1469-7793.2001.00395.x
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发表时间：
2001-07-15
影响因子：
5.5
通讯作者：
Leblanc, N
中科院分区：
文献类型：
--
作者：
Greenwood, IA;Ledoux, J;Leblanc, N
1.在兔肺动脉（PA）、冠状动脉（CA）和门静脉（PV）平滑肌细胞上记录钙激活氯电流（I-Cl（Ca））。比较三种细胞的特性及Ca2 +-钙调素依赖性激酶II（CaMKII）的调节作用.在PA和CA肌细胞透析和灌流与K +-无媒体，移液管解决方案含有固定水平的游离Ca2+在250 nM至1 μ M的范围内诱发良好的持续，向外整流电流在约90%的细胞。CaMKII抑制剂KN-93（5al）可增加PA和CA心肌细胞I-Cl（Ca）的幅值。然而，检测这种效果的阈值细胞内Ca2+浓度是不同的两种动脉细胞类型。KN-93还增强了去极化步骤中时间依赖性电流的激活速率，减慢了复极化后尾电流的动力学，并诱导稳态激活曲线的负移。在PA肌细胞中，KN-93的作用并不反映其无活性类似物KN-92，但通过在移液管溶液中加入autocamtide-2相关的CaMKII抑制肽（ARIP）来复制。用组成型活性CaMKII（30 nM）进行细胞透析显著降低了由500 nM Ca2+诱发的I-Cl（Ca）。在PV肌细胞中，I-Cl（Ca）诱发的移液管溶液含有高达1 μ M的游离Ca2+在不到40%的细胞。KN-93应用于持续I-Cl（Ca）的细胞，在70%的细胞中产生了对电流的小抑制（类似于25%）。目前的研究表明，调节Ca2+依赖性的Cl-通道的CaMKII之间的动脉和门静脉肌细胞不同。
1. Ca2+-activated chloride currents (I-Cl(Ca)) were recorded from smooth muscle cells isolated from rabbit pulmonary (PA) and coronary artery (CA) as well as rabbit portal vein (PV). The characteristics and regulation by Ca2+-calmodulin-dependent kinase II (CaMKII) were compared between the three cell types.2. In PA and CA myocytes dialysed and superfused with K+-free media, pipette solutions containing fixed levels of free Ca2+ in the range of 250 nM to 1 muM evoked well sustained, outwardly rectifying currents in about 90% of cells. The CaMKII inhibitor KN-93 (5 al) increased the amplitude of I-Cl(Ca) in PA and CA myocytes. However, the threshold intracellular Ca2+ concentration for detecting this effect was different in the two arterial cell types. KN-93 also enhanced the rate of activation of the time-dependent current during depolarising steps, slowed the kinetics of the tail current following repolarisation, and induced a negative shift of the steady-state activation curve.3. In PA myocytes, the effects of KN-93 were not mirrored by its inactive analogue KN-92 but were reproduced by the inclusion of autocamtide-2-related CaMKII inhibitory peptide (ARIP) in the pipette solution. Cell dialysis with constitutively active CaMKII (30 nM) significantly reduced I-Cl(Ca) evoked by 500 nM Ca2+.4. In PV myocytes, I-Cl(Ca) was evoked by pipette solutions containing up to 1 muM free Ca2+ in less than 40% of cells. Application of KN-93 to cells where I-Cl(Ca) was sustained produced a small inhibition (similar to 25 %) of the current in 70% of the cells.5. The present study shows that regulation of Ca2+-dependent Cl- channels by CaMKII differs between arterial and portal vein myocytes.