Park Sang Woong, Byun Doyoung, Bae Young Min, Choi Bok Hee, Park Seung Hwa, Kim Bokyung, Cho Sung Il
Artificial Muscle Research Center, Konkuk University, Choongju, Republic of Korea.
Biochem Biophys Res Commun. 2007 Jul 13;358(4):1021-7. doi: 10.1016/j.bbrc.2007.05.024. Epub 2007 May 14.
We examined the effects of fluid flow on L-type voltage-dependent Ca(2+) channel (VDCC(L)) currents in rat vascular myocytes using the nystatin perforated patch-clamp technique. The effect of fluid flow on the liquid (bathing solution)-metal (Ag/AgCl ground electrode) junction potential was also studied. With a fluid flow of 0-10 ml/min, changes in the junction potential of up to 5 mV were observed in proportion to the flow rate. Accordingly, fluid flow shifted the current-voltage (I-V) relationship of the recorded VDCC(L) currents in a positive direction. In addition to these shifts, fluid flow also increased the peak VDCC(L) current, suggesting some modulatory role for fluid flow in VDCC(L) currents. The use of a 3-M KCl agar-bridge between the ground electrode and bathing solution abnegated the potential shifts, and fluid flow increased the VDCC(L) currents in a voltage-independent manner. These results suggest that the bathing fluid flow can be both a source of erroneous voltage shift between liquid and metal junctions in the patch-clamp configuration and an important shear stress for the cells. The facilitation of VDCC(L) currents by fluid flow in vascular myocytes may contribute to the myogenic contraction of blood vessels. The mechanism by which fluid flow causes the voltage shift is vigorously discussed.
我们使用制霉菌素穿孔膜片钳技术研究了流体流动对大鼠血管平滑肌细胞中L型电压依赖性钙通道（VDCC(L)）电流的影响。还研究了流体流动对液体（浴液）-金属（Ag/AgCl接地电极）结电位的影响。当流体流速为0-10 ml/min时，观察到结电位变化高达5 mV，且与流速成正比。因此，流体流动使记录的VDCC(L)电流的电流-电压（I-V）关系正向移动。除了这些移动外，流体流动还增加了VDCC(L)电流峰值，表明流体流动对VDCC(L)电流具有某种调节作用。在接地电极和浴液之间使用3-M KCl琼脂桥消除了电位移动，并且流体流动以电压非依赖性方式增加了VDCC(L)电流。这些结果表明，在膜片钳配置中，浴液流动既可能是液体与金属结之间错误电压偏移的来源，也是作用于细胞的重要剪切应力。流体流动对血管平滑肌细胞中VDCC(L)电流的促进作用可能有助于血管的肌源性收缩。目前正在积极讨论流体流动导致电压偏移的机制。
