Matsumura C, Kuwashima H, Kimura T
Department of Dental Pharmacology, The Nippon Dental University School of Dentistry at Niigata, Hamauracho, Japan.
J Auton Pharmacol. 1999 Apr;19(2):115-21. doi: 10.1046/j.1365-2680.1999.00125.x.
We have used stage-specific assays for ATP-dependent priming and for Ca(2+)-activated triggering in the absence of ATP to examine the effects of myosin light chain kinase (MLCK) inhibitors, ML-9 and ML-7, and calmodulin antagonists, W-7 and trifluoperazine (TFP), on regulated exocytosis in beta-escin-permeabilized bovine adrenal chromaffin cells. Ca2+ (0.1-30 microM) induced a significantly greater secretion of catecholamines in the presence of MgATP (2 mM) than in the absence of MgATP. ML-9 (30 and 100 microM), ML-7 (30 and 100 microM), W-7 (30 and 100 microM) and TFP (10 and 30 microM) inhibited the Ca(2+)-induced catecholamine secretion in the presence of MgATP, but did not affect the catecholamine response to Ca2+ in the absence of MgATP. In intact cells all these compounds inhibited catecholamine secretion in responses to acetylcholine (100 microM) and high K+ (40 mM). The results obtained in permeabilized cells suggest that the calmodulin-MLCK system plays an essential role in the ATP-requiring priming stage but not in the Ca2(+)-triggered fusion step in the exocytotic process in bovine adrenal chromaffin cells.
我们使用了针对ATP依赖性引发以及在无ATP情况下Ca(2+)激活触发的阶段特异性检测方法，来研究肌球蛋白轻链激酶（MLCK）抑制剂ML-9和ML-7以及钙调蛋白拮抗剂W-7和三氟拉嗪（TFP）对β-七叶皂苷通透的牛肾上腺嗜铬细胞中调节性胞吐作用的影响。在存在MgATP（2 mM）的情况下，Ca2+（0.1 - 30 microM）诱导的儿茶酚胺分泌比无MgATP时显著更多。ML-9（30和100 microM）、ML-7（30和100 microM）、W-7（30和100 microM）和TFP（10和30 microM）在存在MgATP时抑制了Ca(2+)诱导的儿茶酚胺分泌，但在无MgATP时不影响儿茶酚胺对Ca2+的反应。在完整细胞中，所有这些化合物都抑制了对乙酰胆碱（100 microM）和高钾（40 mM）反应的儿茶酚胺分泌。在通透细胞中获得的结果表明，钙调蛋白-MLCK系统在牛肾上腺嗜铬细胞胞吐过程中需要ATP的引发阶段起重要作用，但在Ca2(+)触发的融合步骤中不起作用。
