CALCIUM GRADIENTS AND EXOCYTOSIS IN CHROMAFFIN CELLS

描述（改编自研究者的申请）：Ca2+进入 通过电压敏感的Ca2+通道是胞吐的触发器， 可兴奋细胞 最近的证据表明，空间定位的Ca2+ 梯度对于调节胞吐作用是重要的。 这个目标 提出了将脉冲激光钙离子成像与共焦光斑技术联合收割机 用最先进的测量方法检测Ca2+瞬变 单细胞胞吐（膜片钳和伏安测量） 为了研究Ca2+梯度对胞吐的调节， 肾上腺嗜铬细胞 这些实验旨在解决 以下问题。 (1)是什么生理机制控制着 胞吐部位Ca 2+梯度的发展和程度？ (2)什么 是Ca2+梯度和胞吐作用之间的关系， 去极化刺激？ (3)短去极化序列， 高效的胞吐刺激，改变Ca2+梯度， 募集分泌囊泡 (4)Ca2+通道的作用 在Ca2+信号定位和Ca2+缓冲？ (5)做 胞吐位点表现为功能性“活性区”？ （6）什么是 Ca2+梯度和GTP结合蛋白在分泌性细胞募集中的作用 囊泡到胞吐部位

DESCRIPTION (adapted from the investigator's application): Ca2+ entry through voltage sensitive Ca2+ channels is the trigger for exocytosis in excitable cells. Recent evidence suggests that spatially localized Ca2+ gradients are important for regulating exocytosis. The goal of this proposal is to combine the pulsed laser Ca2+ imaging and confocal spot detection of Ca2+ transients with state-of-the-art methods for measuring exocytosis from single cells (patch clamp and voltametric measurements) in order to investigate the regulation of exocytosis by Ca2+ gradients in adrenal chromaffin cells. The experiments are designed to address the following questions. (1) What are the physiological mechanisms that control the development and extent of Ca2+ gradients at exocytotic sites? (2) What is the relationship between the Ca2+ gradients and exocytosis during depolarizing stimuli? (3) How do trains of short depolarizations, which are highly effective stimuli for exocytosis, alter the Ca2+ gradients and recruit secretory vesicles? (4) What are the roles of Ca2+ channel localization and Ca2+ buffers in Ca2+ signal localization? (5) Do the exocytotic sites behave as functional 'active zones'? And (6) what are the roles of Ca2+ gradients and GTP-binding proteins in recruitment of secretory vesicles to the exocytotic sites?