EXOCYTOSIS FROM ADRENAL CHROMAFFIN CELLS

肾上腺髓质儿茶酚胺的钙依赖性胞吐作用 嗜铬细胞是肾上腺髓质和 对心血管和新陈代谢有重要影响。它还可用作 儿茶酚胺和其他神经递质的胞吐模型 来自神经末梢和细胞的激素。研究中的一个主要问题 胞吐作用是指不能改变细胞内环境。 细胞以一种可重现和方便的方式。在初步研究中，我们 用洋地黄使牛肾上腺质膜渗漏 骨髓细胞单层培养至胞外钙离子及可溶性 胞浆蛋白在不明显改变储存颗粒的情况下 稳定性。洋地黄素治疗暴露细胞内突起 参与胞吐作用以指导实验操作。胞吐作用 洋地黄素处理的嗜铬细胞需要微摩尔的钙离子，并且是最佳的 在含镁三磷酸腺苷溶液中。经洋地黄素处理的嗜铬细胞 用于研究胞吐作用所涉及的细胞内过程。这就做 表征和研究二价离子和三磷酸腺苷的依赖性， 钙质蛋白的作用，以及其他可溶性胞浆蛋白的作用 蛋白质磷酸化，以及渗透力在胞吐作用中的作用。

The Ca++ dependent exocytosis of catecholamine from adrenal medullary chromaffin cells is fundamental to the function of the adrenal medulla and has important cardiovascular and metabolic effects. It also serves as a model for exocytosis of catecholamines and other neurotransmitters and hormones from nerve terminals and cells. A major problem in the study of exocytosis has been the inability to alter the intracellular milieu of cells in a reproducible and convenient manner. In a preliminary study we have rendered leaky with digitonin the plasma membrane of bovine adrenal medullary cells in monolayer culture to extracellular Ca++ and soluble cytosolic proteins without significantly altering storage granule stability. Digitonin treatment exposes the intracellular processes involved in exocytosis to direct experimental manipulation. Exocytosis in digitonin-treated chromaffin cells requires micromolar Ca++ and is optimal in MgATP-containing solution. Digitonin-treated chromaffin cells will be used to study the intracellular processes involved in exocytosis. I will characterize and investigate the divalent ion and ATP dependencies, the role of calmoculin, and other soluble cytosolic proteins, the role of protein phosphorylation, and the role of osmotic forces in exocytosis.