P1075和吡那地尔对条件永生化肾小球系膜细胞中一种非钙依赖性氯电导的抑制作用。

Inhibition by P1075 and pinacidil of a calcium-independent chloride conductance in conditionally-immortal renal glomerular mesangial cells.

作者信息

Barber R D, Henderson R M

机构信息

Department of Pharmacology, University of Cambridge.

出版信息

Br J Pharmacol. 1996 Oct;119(4):772-8. doi: 10.1111/j.1476-5381.1996.tb15739.x.

DOI:10.1111/j.1476-5381.1996.tb15739.x

PMID:8904654

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1915769/

Abstract

Depolarization of mesangial cells has been shown to occur following an outward movement of chloride ions from the cell. We have shown previously that mesangial cells from the H-2Kb-tsA58 transgenic mouse possess a significant whole-cell chloride conductance and consequently are a suitable preparation for the study of potential chloride channel inhibitors. 2. The effects on the whole-cell chloride conductance of the chloride channel inhibitor, 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) and the potassium channel openers, (KCOs) P1075 and pinacidil were investigated in mesangial cells from the H-2Kb-tsA58 transgenic mouse cultured in permissive conditions (at 33 degrees C in the presence of 50 u ml-1 murine gamma-interferon). 3. In symmetrical solutions of 140 mM tetramethylammonium chloride (TMAC1) the whole-cell chloride conductance was 1.08 +/- 0.05 nS (n = 63) and this could be reversibly inhibited by 5 x 10(-5) M NPPB. 4. Both P1075 and pinacidil inhibited the whole-cell chloride conductance. This inhibition was not reversible after drug washout and was demonstrated only when drugs were applied to the extracellular surface of the cells. Very low concentrations of the drugs were found to reduce the chloride conductance after 16 h incubation but under no circumstances studied was the conductance totally inhibited, leaving a mean residual current of 0.33 +/- 0.03 nS (n = 12). 5. The effects of different peptide calcium concentrations on the magnitude of the residual current in the presence of the drugs were investigated. The residual current was reduced with 10(-8) M calcium in the pipette and increased with 10(-3) M pipette calcium. Therefore, these data suggest that P1075 and pinacidil selectively inhibit a calcium-independent chloride conductance in mesangial cells from the H-2Kb-tsA58 transgenic mouse.

摘要

系膜细胞的去极化已被证明是在氯离子从细胞向外移动后发生的。我们之前已经表明，来自H-2Kb-tsA58转基因小鼠的系膜细胞具有显著的全细胞氯电导，因此是研究潜在氯通道抑制剂的合适标本。2. 在允许条件下（33摄氏度，存在50μl/ml小鼠γ干扰素）培养的来自H-2Kb-tsA58转基因小鼠的系膜细胞中，研究了氯通道抑制剂5-硝基-2-(3-苯丙基氨基)-苯甲酸酯（NPPB）以及钾通道开放剂（KCOs）P1075和匹那地尔对全细胞氯电导的影响。3. 在140mM四甲基氯化铵（TMAC1）的对称溶液中，全细胞氯电导为1.08±0.05nS（n = 63），这可被5×10⁻⁵M NPPB可逆抑制。4. P1075和匹那地尔均抑制全细胞氯电导。药物洗脱后这种抑制不可逆，且仅当药物应用于细胞的细胞外表面时才表现出来。发现极低浓度的药物在孵育16小时后会降低氯电导，但在任何研究的情况下电导都未被完全抑制，留下的平均残余电流为0.33±0.03nS（n = 12）。5. 研究了不同肽钙浓度对药物存在时残余电流大小的影响。移液管中10⁻⁸M钙会降低残余电流，而移液管中10⁻³M钙会增加残余电流。因此，这些数据表明P1075和匹那地尔选择性抑制来自H-2Kb-tsA58转基因小鼠的系膜细胞中与钙无关的氯电导。