Watsky M A
Department of Physiology and Biophysics, University of Tennessee, Memphis 38163, USA.
Am J Physiol. 1995 Dec;269(6 Pt 1):C1385-93. doi: 10.1152/ajpcell.1995.269.6.C1385.
The influence of serum, lysophosphatidic acid (LPA), and hyposmotic stress on the ion channel activity of normal and cryo-injured rabbit corneal keratocytes was investigated. Whole cell currents were examined using the amphotericin perforated-patch technique. In cells from wounded corneas, fetal bovine serum activated large, holding voltage-insensitive, fast-activating, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)-, flufenamic acid-, and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB)-blockable outward currents showing inactivation at depolarized voltages. LPA activated identical currents, also only in cells from wounded corneas. Blocker and reversal potential experiments characterized the current as a Cl- currents (Icl). Lysophosphatidylcholine (10 microM) failed to activate the current. An identical current was activated by hyposmotic stimulation in cells from control and wounded corneas. Hyposmotic stimulation also activated Icl in cells from wounded corneas that were unresponsive to LPA. We conclude that serum, LPA, and hypotonic stress activate Icl in keratocytes from wounded corneas. We also conclude that LPA is a serum factor that can activate Icl and that hyposmotic activation may work through a signaling pathway separate from that of LPA.
研究了血清、溶血磷脂酸（LPA）和低渗应激对正常及冷冻损伤兔角膜基质细胞离子通道活性的影响。采用两性霉素穿孔膜片钳技术检测全细胞电流。在来自受伤角膜的细胞中，胎牛血清激活了大的、与钳制电压不敏感、快速激活、可被4,4'-二异硫氰基芪-2,2'-二磺酸（DIDS）、氟芬那酸和5-硝基-2-（3-苯丙基氨基）苯甲酸（NPPB）阻断的外向电流，该电流在去极化电压下表现出失活。LPA也仅在来自受伤角膜的细胞中激活了相同的电流。阻断剂和反转电位实验将该电流表征为氯离子电流（Icl）。溶血磷脂酰胆碱（10 microM）未能激活该电流。低渗刺激在来自对照和受伤角膜的细胞中激活了相同的电流。低渗刺激也在对LPA无反应的来自受伤角膜的细胞中激活了Icl。我们得出结论，血清、LPA和低渗应激激活了来自受伤角膜的基质细胞中的Icl。我们还得出结论，LPA是一种可激活Icl的血清因子，且低渗激活可能通过与LPA不同的信号通路起作用。
