牛肾上腺嗜铬细胞中咖啡因诱导的胞吐作用缺乏Ca2+和ATP依赖的引发阶段：与Ca2+的比较。

Lack of Ca2+- and ATP-dependent priming stage in caffeine-induced exocytosis in bovine adrenal chromaffin cells: comparison with Ca2+.

Matsumura C, Kuwashima H, Kimura T

Department of Dental Pharmacology, The Nippon Dental University School of Dentistry at Niigata, Hamauracho, Japan.

J Auton Pharmacol. 2000 Feb;20(1):31-6. doi: 10.1046/j.1365-2680.2000.00161.x.

Abstract

Caffeine (20-40 mM) secreted catecholamines from beta-escin-permeabilized bovine adrenal chromaffin cells in the presence or absence of 2 mM MgATP. The caffeine-induced catecholamine secretion in the presence of MgATP was to the same extent as that in the absence of MgATP. 2. Ca2+ (0.1-10 microM) induced a significantly greater secretion of catecholamines in the presence of MgATP than in the absence of MgATP. 3. ML-9 (100 microM) and ML-7 (100 microM), myosin light chain kinase inhibitors, and W-7 (100 microM) and trifluoperazine (TFP; 30 microM), calmodulin antagonists, inhibited the Ca2+-induced catecholamine secretion in the presence of MgATP but not in the absence of MgATP. They did not inhibit the caffeine-induced catecholamine secretion in the presence of MgATP. 4. The ATP-independent phase in Ca2+-dependent exocytosis is thought to be associated with the final step that ultimately leads to fusion, while the ATP-dependent phase is thought to be associated with a vesicle priming reaction. Therefore, these results suggest that the ATP-requiring priming stage is lacking in the process of caffeine-induced exocytosis in bovine adrenal chromaffin cells.

摘要

在存在或不存在2 mM MgATP的情况下，咖啡因（20 - 40 mM）可促使经β-七叶皂苷通透处理的牛肾上腺嗜铬细胞分泌儿茶酚胺。在存在MgATP时咖啡因诱导的儿茶酚胺分泌与不存在MgATP时的程度相同。2. 在存在MgATP的情况下，Ca2 +（0.1 - 10 microM）诱导的儿茶酚胺分泌比不存在MgATP时显著更多。3. 肌球蛋白轻链激酶抑制剂ML - 9（100 microM）和ML - 7（100 microM），以及钙调蛋白拮抗剂W - 7（100 microM）和三氟拉嗪（TFP；30 microM），在存在MgATP时抑制Ca2 +诱导的儿茶酚胺分泌，但在不存在MgATP时则不抑制。它们在存在MgATP时不抑制咖啡因诱导的儿茶酚胺分泌。4. 依赖Ca2 +的胞吐作用中不依赖ATP的阶段被认为与最终导致融合的最后一步相关，而依赖ATP的阶段被认为与囊泡引发反应相关。因此，这些结果表明在牛肾上腺嗜铬细胞咖啡因诱导的胞吐作用过程中缺乏需要ATP的引发阶段。