CALCIUM GRADIENTS AND EXOCYTOSIS IN CHROMAFFIN CELLS

描述(改编自调查人员的申请)：CA2+条目 通过电压敏感的钙通道是胞吐作用的触发因素 可兴奋的细胞。最近的证据表明，空间定域化的钙离子 梯度对于调节胞吐作用很重要。这样做的目的是 建议将脉冲激光钙离子成像与共聚焦光斑相结合 用最先进的测量方法检测钙瞬变 单细胞胞吐作用(膜片钳和伏安法) 为探讨钙离子梯度对胞吐作用的调节作用。 肾上腺嗜铬细胞。这些实验旨在解决 以下是问题。(1)控制的生理机制是什么 胞吐部位钙离子梯度的发展和程度？(2)什么 钙离子梯度与胞吐作用之间的关系 去极化刺激？(3)短的去极化序列是如何 高效的胞吐刺激，改变钙离子梯度和 招募分泌小泡？(4)钙通道的作用是什么 钙信号定位中的定位和钙缓冲？(5) 胞吐部位是功能性的“活动区”吗？和(6)什么是 钙离子梯度和GTP结合蛋白在分泌物募集中的作用 到胞吐部位的囊泡？

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?