Mechanisms of Alcohol Withdrawal Seizures: Role of L-type Ca2+ Channels

酒精戒断发作的机制：L 型 Ca2 通道的作用

• 批准号: 8185879
• 负责人: Prosper N'Gouemo
• 金额: $ 28.22万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-01 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8185879
• 关键词: Accounting; Alcohol Withdrawal Seizures; Alcohol abuse; Alcohol withdrawal syndrome; Biological Assay; Brain; Brain Stem; Cell Surface Proteins; Cell surface; Cyclic AMP-Dependent Protein Kinases; Data; Dihydropyridines; Electrophysiology (science); Emergency Situation; Epilepsy; Etiology; Exhibits; Gene Expression; Goals; Human; Inferior Colliculus; Knockout Mice; Literature; Medical; Medicine; Messenger RNA; Microinjections; Modeling; Molecular; Molecular Genetics; Molecular Target; Mus; Neurons; Outcome; Pattern; Pharmacology; Phosphorylation; Play; Predisposition; Preparation; Prevention; Principal Investigator; Property; Protein Subunits; Proteins; Public Health; Publishing; RNA; RNA Interference; Rattus; Reporting; Research; Research Proposals; Resistance; Risk; Role; Seizures; Signal Transduction; Slice; Testing; Tonic - clonic seizures; Western Blotting; Withdrawal; Work; alcohol response; base; channel blockers; crosslink; density; dihydropyridine; effective therapy; improved; in vivo; innovation; knock-down; mRNA Expression; novel therapeutic intervention; novel therapeutics; prevent; programs; protein expression; research study

DESCRIPTION (provided by applicant): Alcohol withdrawal seizures (AWS) are one of the most common medical emergencies, but their underlying mechanisms are poorly understood. The inferior colliculus (IC) is thought to play an important role in initiating acoustically-evoked AWS. In a rat model, epileptiform bursts from IC neurons are critical in initiating acoustically-evoked AWS, and dihydropyridines (L-type Ca2+ channels blockers) suppressed these seizures. The extent to which L-type Ca2+ channels (LTCCs) contribute to generating epileptiform bursts in IC neurons following alcohol withdrawal is unknown. Which of the two LTCC classes (CaV1.2 and CaV1.3) present in IC neurons contribute to AWS is also unknown. Our overall goal is to understand how controlling LTCCs and related Ca2+ signaling can be use to prevent and treat AWS. The objective of this application is to investigate AWS etiology in rats and mice by determining the role of LTCCs in the mechanisms underlying IC neuronal hyperexcitability in response to alcohol withdrawal. Our central hypothesis is that CaV1.3 LTCC activity is required for IC neurons to generate epileptiform bursts that initiate AWS. This hypothesis is based on substantial preliminary data from our rat AWS model, with further support from published reports that: i) blockade of LTCCs suppresses acoustically-evoked AWS, ii) the current density of LTCCs increases markedly in IC neurons following alcohol withdrawal associated with enhanced seizure susceptibility, and iii) LTCCs of the other class, CaV1.2, are not upregulated in IC neurons following alcohol withdrawal. The rationale for the proposed research is that understanding the role of LTCCs in AWS initiation has the potential to improve our ability to prevent and control these seizures. Our central hypothesis will be tested by pursuing three specifics aims: 1) Determine to what extent LTCCs contribute to generating epileptiform bursts and Ca2+ spikes in IC neurons following alcohol withdrawal; 2) Determine to what extent phosphorylation, cell surface protein expression, and mRNA expression of CaV1.3 LTCCs are associated with the enhanced current density in IC neurons following alcohol withdrawal; and 3) Determine if acoustically-evoked AWS can be generated in CaV1.3a1 knockout mice and rats in which CaV1.3a1 subunits are knocked down by short-interfering RNA microinjection into IC neurons. Our approach is innovative because it uses molecular genetics combined with electrophysiology and pharmacology to determine the role of CaV1.3 LTCCs in IC neuronal hyperexcitability and resulting AWS. Our proposed research is significant because the experiments will identify an LTCC- dependent mechanism essential to AWS initiation, fundamentally advancing the field of alcohol abuse and identifying a new molecular target for novel therapeutic approaches to AWS prevention and treatment. PHS 398/2590 (Rev. 06/09) Page Continuation Format Page PUBLIC HEALTH RELEVANCE: Alcohol withdrawal seizures (AWS) are one of the most common medical emergencies, but low risk, effective therapies are lacking. L-type Ca2+ channels are thought to be implicated in neuronal firing patterns in the brain known to initiate AWS in a rat model of the human condition. The proposed research is relevant to public health because the experiments will clarify the role of L-type Ca2+ channels in AWS initiation, which is essential if better medicines for these seizures are to be developed. PHS 398/2590 (Rev. 11/07) Page Continuation Format Page

描述(申请人提供)：酒精戒断发作(AWS)是最常见的医疗紧急情况之一，但其潜在机制尚不清楚。下丘(IC)被认为在启动声诱发的AWS中起着重要作用。在大鼠模型中，IC神经元的癫痫样发作在启动声诱发的AWS中起关键作用，二氢吡啶(L类钙通道阻滞剂)可抑制这些癫痫发作。酒精戒断后，L型钙通道(LTCC)在多大程度上参与了中枢神经元癫痫样发作的发生，目前尚不清楚。IC神经元中存在的两个LTCC类别(CaV1.2和CaV1.3)中的哪一个对AWS有贡献也是未知的。我们的总体目标是了解如何利用控制LTCC和相关的钙信号来预防和治疗AWS。本应用的目的是通过确定LTCCs在酒精戒断反应中IC神经元过度兴奋的机制中的作用，来研究AWS的病因学。我们的中心假设是，CaV1.3 LTCC活动是IC神经元产生癫痫样脉冲从而启动AWS所必需的。这一假说是基于我们的大鼠AWS模型的大量初步数据，并得到了已发表报告的进一步支持，即：i)阻断LTCC可抑制声诱发的AWS，ii)酒精戒断后IC神经元中LTCC的电流密度显著增加，与癫痫敏感性增强相关，以及iii)另一类LTCC CaV1.2在酒精戒断后不在IC神经元中上调。这项拟议研究的基本原理是，了解LTCC在AWS启动中的作用有可能提高我们预防和控制这些癫痫发作的能力。我们的中心假说将通过追求三个特定目标来验证：1)确定LTCC在多大程度上有助于酒精戒断后IC神经元产生癫痫样发作和钙尖峰；2)确定CaV1.3 LTCC的磷酸化、细胞表面蛋白表达和mRNA表达在多大程度上与酒精戒断后IC神经元的电流密度增加有关；以及3)确定是否可以在CaV1.3a1基因敲除的小鼠和大鼠中产生声音诱发的AWS，其中CaV1.3a1亚单位被微注射到IC神经元中。我们的方法是创新的，因为它使用分子遗传学结合电生理学和药理学来确定CaV1.3 LTCC在IC神经元超兴奋性和由此产生的AWS中的作用。我们提出的研究具有重要意义，因为这些实验将识别对启动AWS至关重要的LTCC依赖机制，从根本上推动酒精滥用领域的发展，并为AWS预防和治疗的新治疗方法确定新的分子靶点。PHS 398/2590(06/09版)页面续格式页面 公共卫生相关性：酒精戒断发作(AWS)是最常见的紧急医疗事件之一，但缺乏低风险、有效的治疗方法。L类型的钙通道被认为与大脑中神经元放电模式有关，已知的神经元放电模式在人类条件下的大鼠模型中启动AWS。这项拟议的研究与公共健康相关，因为这些实验将阐明L类型的钙通道在AWS启动中的作用，如果要开发更好的治疗这些癫痫发作的药物，这是必不可少的。PHS 398/2590(11/07版)页面续格式页面