Greenwood I A, Large W A
Department of Pharmacology and Clinical Pharmacology, St. George's Cardiovascular Research Group, St. George's Hospital Medical School, London SW17 0RE, United Kingdom.
Am J Physiol. 1998 Nov;275(5):H1524-32. doi: 10.1152/ajpheart.1998.275.5.H1524.
In rabbit portal vein smooth muscle cells, application of a hypotonic external solution caused cell swelling and evoked an outwardly rectifying Cl- current. The hypotonicity-activated current was markedly reduced by the anti-estrogen tamoxifen (10 microM) and was inhibited by DIDS in a voltage-dependent manner [the concentration required to inhibit the current by 50% (IC50) at -50 and +100 mV was 21 and 5 microM DIDS, respectively]. Indanyloxyacetic acid 94 (IAA-94) and niflumic acid also inhibited the hypotonicity-activated current, with 50% inhibition produced at concentrations of approximately 200 and 100 microM, respectively. In isotonic conditions, application of tamoxifen and DIDS to cells decreased the holding current due to the inhibition of a resting conductance that was outwardly rectifying and reversed at the Cl- equilibrium potential. These data show that rabbit portal vein myocytes have a resting Cl- conductance that is enhanced by cell swelling; its possible physiological role is discussed.
在兔门静脉平滑肌细胞中，应用低渗外部溶液会导致细胞肿胀并诱发外向整流性氯离子电流。抗雌激素他莫昔芬（10微摩尔）可显著降低低渗激活电流，二异丙基氨基磺酸钠（DIDS）以电压依赖性方式抑制该电流[-50和+100毫伏时抑制电流50%（半数抑制浓度，IC50）所需的DIDS浓度分别为21和5微摩尔]。茚满氧基乙酸94（IAA-94）和氟尼酸也抑制低渗激活电流，分别在约200和100微摩尔浓度时产生50%的抑制作用。在等渗条件下，将他莫昔芬和DIDS应用于细胞会降低钳制电流，这是由于抑制了一种外向整流且在氯离子平衡电位处反转的静息电导。这些数据表明兔门静脉肌细胞具有一种静息氯离子电导，该电导会因细胞肿胀而增强；文中讨论了其可能的生理作用。
