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Regulation of voltage-gated calcium channels during chronic BZ treatment in rats

大鼠慢性 BZ 治疗过程中电压门控钙通道的调节

基本信息

批准号：
8447061
负责人：
Damien Eugene Earl
金额：
$ 1.24万
依托单位：
UNIVERSITY OF TOLEDO HEALTH SCI CAMPUS
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-04-01 至 2013-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8447061
关键词：
Accident and Emergency department Address Adolescent Aminobutyric Acids Anxiety Anxiety Disorders Benzodiazepines Brain Calcium Calcium Channel Calcium Channel Inhibition Cells Central Nervous System Depressants Chronic Clinical Dependence Diazepam Dihydropyridines Electrons Embryo Epilepsy Ethanol Excision Fluorescent Dyes Flurazepam Fura-2 Glutamate Receptor Half-Life High voltage activated calcium channel Hippocampus (Brain)Human Image Imaging Techniques Immunoblotting Kidney Label Lead Light Link Measures Mediating Membrane Membrane Potentials Methods Microscopic Modeling Monitor Neuraxis Neurons Nimodipine Patch-Clamp Techniques Pharmaceutical Preparations Pharmacologic Substance Phosphorylation Physical Dependence Physiological Play Protocols documentation Rattus Recombinants Regulation Reporting Role Sleeplessness Slice Societies Substance Withdrawal Syndrome Surface T-Lymphocyte Techniques Testing Time Visit Water Withdrawal density dihydropyridine drug of abuse drug withdrawal gamma-Aminobutyric Acid hippocampal pyramidal neuron in vivo kidney cell new therapeutic target nonmedical use novel prevent prototype ratiometric receptor receptor function trafficking voltage

项目摘要

DESCRIPTION (provided by applicant): Benzodiazepines (BZs) enhance inhibitory gamma-aminobutyric acid type A receptors (GABARs) in the central nervous system and are clinically used to treat insomnia, anxiety, and seizure disorders. Misuse of CNS depressant drugs, such as the BZs, is of growing concern. There has been increased non-medical use of CNS depressants among adolescents since 2001 and BZ misuse and abuse resulted in over 150,000 emergency room visits in 2004. Of particular concern is the fact that chronic BZ use can lead to physical dependence manifested by a withdrawal syndrome, which limits the clinical usefulness of BZs. Our lab models BZ dependence using a well-established protocol of chronic treatment of rats with the BZ, fluraze- pam (FZP). We have linked withdrawal anxiety to enhanced excitatory receptor function in the rat hippocam- pal CA1 region. We also discovered that voltage-gated calcium channel (VGCC) current density doubles during chronic FZP treatment and remains elevated following withdrawal. Interestingly, selectively blocking calcium influx through L-type VGCCs with nimodipine prevented the excitatory receptor changes and associated withdrawal anxiety, suggesting that L-VGCCs play a critical role in BZ withdrawal phenomena. The overall objective of this project is to determine the mechanisms of L-VGCC modulation during FZP treatment and withdrawal, as this could suggest a previously unknown mechanism of developing BZ physiological dependence. The specific aims of this project are to: 1) Determine if GABAR-mediated depolarization, known to be induced by chronic BZ treatment, activates L- VGCCs during FZP withdrawal using electrophysiologic and fluorescent calcium-imaging techniques. 2) Investigate changes in L-VGCC subunit expression and phosphorylation after chronic FZP treatment, using immunoblot, immunofluorescent, and electron microscopic techniques. 3) Investigate the often unrecognized ability of BZs to directly modulate L-VGCC function. Direct inhibition of recombinant L-VGCCs by BZs will be measured using whole-cell patch clamp techniques. Chronic misuse of prescription benzodiazepines (BZs) can result in physical dependence and remains a major concern in today's society. The results of this project could reveal a novel mechanism of neuroadaptive changes mediating the BZ withdrawal phenomenon, which current evidence suggests may be similar to other frequently abused CNS depressants, such as ethanol. Elucidation of this mechanism could reveal new therapeutic targets for BZ withdrawal, and possibly withdrawal from other drugs of abuse.

描述（由申请人提供）：苯二氮卓类（BZ）可增强中枢神经系统中的抑制性γ-氨基丁酸A型受体（GABAR），临床上用于治疗失眠、焦虑和癫痫发作。滥用中枢神经系统抑制药物，如BZ，越来越受到关注。自2001年以来，青少年中CNS抑制剂的非医疗使用有所增加，2004年BZ误用和滥用导致超过150，000次急诊室就诊。特别值得关注的是，长期使用BZ可能导致身体依赖，表现为戒断综合征，这限制了BZ的临床用途。我们的实验室模型BZ依赖性使用一个完善的协议，慢性治疗大鼠的BZ，fluraze-pam（FZP）。我们已经将戒断焦虑与大鼠海马CA 1区兴奋性受体功能增强联系起来。我们还发现，电压门控钙通道（VGCC）电流密度在慢性FZP治疗期间加倍，并在停药后保持升高。有趣的是，尼莫地平选择性地阻断钙离子通过L型VGCC的内流阻止了兴奋性受体的变化和相关的戒断焦虑，这表明L-VGCC在BZ戒断现象中起着关键作用。本项目的总体目标是确定FZP治疗和停药期间L-VGCC调节的机制，因为这可能表明以前未知的BZ生理依赖性发展机制。该项目的具体目的是：1）使用电生理学和荧光钙成像技术确定已知由慢性BZ治疗诱导的GABAR介导的去极化是否在FZP戒断期间激活L-VGCC。2)采用免疫印迹、免疫荧光和电子显微镜技术研究慢性FZP治疗后L-VGCC亚基表达和磷酸化的变化。3)研究BZ直接调节L-VGCC功能的能力。将使用全细胞膜片钳技术测量BZ对重组L-VGCC的直接抑制。长期滥用处方苯二氮卓类药物（BZ）可导致身体依赖，仍然是当今社会的一个主要问题。该项目的结果可能揭示一种新的神经适应性变化机制，介导BZ戒断现象，目前的证据表明，这可能类似于其他经常滥用的CNS抑制剂，如乙醇。阐明这一机制可以揭示BZ戒断的新治疗靶点，并可能从其他滥用药物中戒断。