VOLATILE ANESTHETICS AND NEURONAL CALCIUM

挥发性麻醉剂和神经钙

• 批准号: 7032602
• 负责人: THOMAS Joseph John BLANCK
• 金额: $ 31.43万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-10-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7032602
• 关键词: anesthetics; calcium channel; calcium flux; calcium indicator; glutamate receptor; glutamate transporter; glutamates; halothane; isoflurane; laboratory rat; membrane channels; neuroimaging; neuropharmacology; paralysis; spinal ganglion; spinal nerves; tissue /cell culture; voltage /patch clamp; voltage gated channel; anesthetics; calcium channel; calcium flux; calcium indicator; glutamate receptor; glutamate transporter; glutamates; halothane; isoflurane; laboratory rat; membrane channels; neuroimaging; neuropharmacology; paralysis; spinal ganglion; spinal nerves; tissue /cell culture; voltage /patch clamp; voltage gated channel

DESCRIPTION (provided by applicant): Immobility mediated by volatile anesthetics (VAs) appears to result largely from depression of excitatory neurotransmission at the spinal cord level. Neurons transform electrical and chemical stimuli into meaningful physiological signals by the regulation of intracellular Ca2+ concentration and compartmentalization. Chemicals that act at particular Ca2+ regulatory sites have been shown to alter the MAC of VAs. At the cellular level, VAs have been shown to inhibit voltage-dependent Ca2+ channels and Ca2+ transients in neuronal cells. We hypothesize that Volatile anesthetics produce immobility by inhibiting spinal cord neurons through the modulation of Ca2+ channels and signaling. We will test this hypothesis by comparing the effects of tree VAs, isoflurane, halothane, and F3, with that of two structurally related molecules that fail to produce immobility (non-immobilizers (NIMs)), F6 and F8. Effects on voltage-dependent (L- and N-type) and ligand (glutamate)-activated Ca2+ channels, glutamate-mediated neuronal excitability, and glutamate release from synaptosomes will be explored. Initial studies will involve human SH-SY5Y neuroblastoma cells as a model system to identify prospective targets of drug action. We will also study dorsal root ganglion neurons (DRG), and spinal ventral horn (VH)- motor neurons in primary culture as well as synaptosomes, all isolated from the adult rat spinal cord. The specific aims will determine whether VAs and NIMs (1) differ in their block of plasma membrane L- and N-type voltage dependent Ca2+ channels; (2a) differ in their block of capacitative- glutamate activated cationic Ca2+ channels; (2b) change the sensitivity of glutamate for evoking cytoplasmic Ca2+ transients, and action on glutamate-activated ionotropic and/or metabotropic receptors; and (2c) differ in their effect on the presynaptic release of glutamate from spinal cord synaptosomes and its dependence on Ca2+. Whole cell and patch voltage- and current-clamp, and fluorescence methodologies including imaging for measuring intracellular Ca2+, plasma membrane potential, and glutamate release will be employed. The results of these studies will yield important molecular insights into Ca2+ signaling in neurons and clarify the relevance of VA effects on Ca2+ signaling to the immobility aspect of VA-mediated anesthesia.

描述（由申请人提供）：挥发性麻醉药（VAS）介导的固定性似乎主要是由于脊髓水平的兴奋性神经传递的抑郁而导致的。神经元通过调节细胞内Ca2+浓度和分区化，将电和化学刺激转化为有意义的生理信号。在特定CA2+调节位点起作用的化学物质已显示可改变VA的MAC。在细胞水平上，VAS已显示可抑制神经元细胞中电压依赖性的Ca2+通道和Ca2+瞬变。我们假设挥发性麻醉药通过通过调节Ca2+通道和信号传导抑制脊髓神经元来产生固定性。我们将通过比较树Vas，异氟烷，硫烷和F3的影响与两个结构相关的分子（未产生固定性（非Immmobilizers（Nims）），F6和F8的效果。将探索对电压依赖性（L型和N型）和配体（谷氨酸）激活CA2+通道，谷氨酸介导的神经元兴奋性以及突触体释放谷氨酸的影响。最初的研究将涉及人类SY5Y神经母细胞瘤细胞作为模型系统，以识别药物作用的前瞻性靶标。我们还将研究背根神经神经元（DRG）和脊柱腹角（VH） - 原发性培养物和突触体中的运动神经元，为运动小体，为成年大鼠脊髓分离。具体的目的将确定VAS和NIMS（1）在其质膜L和N型电压依赖性Ca2+通道的块中是否有所不同； （2a）它们的电容 - 谷氨酸激活的阳离子Ca2+通道的块有所不同； （2b）改变谷氨酸对诱发细胞质Ca2+瞬变的敏感性，并对谷氨酸激活的离子型和/或代替受体的作用； （2C）它们对从脊髓突触小体从突触前释放的影响及其对Ca2+的依赖性的影响。全细胞和斑块电压和电流夹，以及荧光方法，包括用于测量细胞内Ca2+，质膜电位和谷氨酸释放的成像。这些研究的结果将产生对神经元中Ca2+信号传导的重要分子见解，并阐明VA对Ca2+信号的影响与VA介导的麻醉的不动性方面的相关性。