VOLATILE ANESTHETICS AND NEURONAL CALCIUM

神经元将电和化学刺激转化为 钙离子转位和钙离子传递的生理意义信息 重新分配。调查人员将在拟议的 研究表明，挥发性麻醉剂(VA)、氟烷和异氟烷， 干扰正常的细胞外和细胞内钙转运和 分布，以及VA对钙稳态(转位和 重分布)取决于刺激的类型。研究将在一个 人神经母细胞瘤细胞系SH-SY5Y细胞 肾上腺素能神经元，在原代培养的大鼠海马神经元和在 转染N型钙通道α和β亚基的HEK293细胞。 利用细胞内钙荧光、单通道和全细胞 膜片钳，去甲肾上腺素(NA)分泌的放射性同位素测量，以及 分子生物学技术产生N型钙通道，我们将 实现以下具体目标：1)确定调解机制 维生素A诱导K-诱发的细胞[Ca~(2+)]-Cyt瞬变增加并确定 Va还能增强电刺激引起的[Ca~(2+)]Cyt瞬变； 找出导致维生素A诱导的抑郁的机制 卡巴胆碱诱发的[钙]细胞；瞬变；3)研究钙的来源 调节VA对神经元L型钙通道的作用；4)研究VA 对N型钙通道的作用及G蛋白的参与； 研究哪些钙来源对于调节NA的释放是重要的， VA暴露是否改变[Ca~(2+)]Cyt和NA释放之间的关系， 并确定VA对NA释放的作用是否依赖于暴露 Vas的时间到了。这些调查的结果将有助于确定 钙稳态的改变是血管紧张素转换酶的基本作用 它们与麻醉过程直接相关。这项研究将导致 作为VA靶标的细胞器和分子的鉴定 将有助于未来更具体的麻醉药的开发。

Neurons translate electrical and chemical stimuli into physiologically meaningful information by Ca2+ translocation and redistribution. The hypothesis the investigators will test in the proposed studies is that the volatile anesthetics (VA), halothane and isoflurane, interfere with normal extra- and intracellular Ca2+ translocation and distribution, and that the VA effect on Ca2+ homeostasis (translocation and redistribution) depends on the type of stimuli. Studies will be performed in a human neuroblastoma cell line, SH-SY5Y cells, that has many characteristics of adrenergic neurons, in rat hippocampal neurons in primary culture, and in HEK293 cells transfected with alpha and beta subunits of N-type Ca2+ channels. Using intracellular Ca2+ fluorescence, single channel and whole cell patch-clamp, radioisotopic measurement of noradrenaline (NA) secretion, and molecular biologic techniques to generate N-type Ca2+ channels, we will accomplish the following specific aims: 1) identify the mechanisms mediating the VA-induced increase in the K+-evoked [Ca2+]cyt transient and determine if VA also enhance [Ca2+]cyt transients resulting from electrical stimulation; 2) identify the mechanisms that lead to the VA-induced depression of the Carbachol-evoked [Ca2+]cyt; transient; 3) investigate the source of Ca2+ that modulates the VA action on neuronal L-type Ca2+ channels; 4) investigate the VA action on N-type Ca2+ channels, and the involvement of G-proteins; and 5) investigate which sources of Ca2+ are important for mediating NA release, whether VA exposure alters the relationship between [Ca2+]cyt and NA release, and determine whether the VA action on NA release is dependent on the exposure time to Vas. The results of these investigations will help to establish that modifications of Ca2+ homeostasis are a fundamental effect of the Vas and that they are directly related to the process of anesthesia. This study will lead to the identification of organelles and molecules that are targets of VA's that will assist in the future development of more specific anesthetic drugs.