Synaptic and intrinsic exitability in motoneurons in a mouse model of ALS.

ALS 小鼠模型中运动神经元的突触和内在可退出性。

基本信息

批准号：
7615431
负责人：
Katharina Ann Quinlan
金额：
$ 5.53万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
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：
2009-01-02 至 2011-01-01
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7615431
关键词：
Acute Adolescent Adult Age Alanine Back Buffers Calcium Cells Cessation of life Chronic Dendrites Development Diagnosis Disease Dyes Effectiveness Electrodes Employee Strikes Evaluation Exposure to FDA approved Future Genes Glutamates Glycine Hypertension Image In Vitro Isradipine Leg Link Mediating Membrane Potentials Methods Motor Neurons Mus Muscle Mutation Napping Neonatal Nerve Degeneration Neurodegenerative Disorders Neurons Newborn Infant Pacemakers Paralysed Parkinson Disease Patients Pharmaceutical Preparations Predisposition Preparation Property Rattus Reflex action Rest Riluzole Route Slice Spinal Cord Substantia nigra structure Superoxide Dismutase Synapses Time Wild Type Mouse Work channel blockers drug development effective therapy excitotoxicity mouse model neuronal excitability patch clamp postnatal presynaptic response

项目摘要

DESCRIPTION (provided by applicant): This study will examine postnatal development of intrinsic and synaptic excitability in motoneurons from the mouse model for familial ALS, the SOD1G93A mouse. ALS is a slowly progressing disease marked by loss of motoneurons resulting in paralysis and finally death. Motoneurons that are vulnerable to ALS have low buffering capacity for intracellular calcium (Ca2+), and excitotoxicity through excessive Ca2+ entry is a possible mechanism of neurodegeneration in ALS. This study will examine changes during maturation in the two main routes excessive Ca2+ entry could occur: increased synaptic excitation and/or an increase in the intrinsic excitability of the motoneuron. Intrinsic excitability is mediated by both persistent Na+ channels (NaP) and Cav1.3 Ca2+ channels which produce the persistent inward current (PIC). Riluzole, the only FDA approved drug for ALS, works in two ways, blocking NaP, and decreasing presynaptic glutamate release. Unfortunately riluzole loses effectiveness over time, so exploration of other potential treatments for ALS is needed. Isradipine, a dihydropiradine antagonist effective in blocking Cav1.3 Ca2+ channels will be applied and motoneuron excitability will be assessed in neonatal, juvenile and adult mice. Although a major portion of the PIC consists of NaP in young rats, during maturation the contribution of Ca2+ increases to about 50%. The adult onset of ALS could be linked to this shift from a Na+ to Ca2+-mediated PIC. In Parkinson's disease, maturation of Na+-dependant pacemaker activity in juvenile substantia nigra neurons to Cav1.3- mediated activity in adults causes degeneration, and if Na+-dependent activity is brought back in adults with prolonged exposure to isradipine, these neurons were less susceptible to the disease. A similar Ca++ dependent susceptibility could develop in aging motoneurons of SOD1G93A mice, and isradipine could be an effective treatment. Therefore I propose to study intrinsic and synaptic excitability, including somal and dendritic Ca2+ levels in normal and SOD1G93A mice and the effects of short- and long-term isradipine exposure on motoneuron hyperexcitability in SOD1G93A mice from neonatal through adult ages. I will record from lumbar and sacral motoneurons using whole cell patch clamp and sharp electrode intracellular recording, and using multiphoton imaging and Ca2+ sensitive dye, examine dendritic Ca2+ influx at all timepoints. This study will assess the potential of a new treatment for ALS, isradipine, a drug currently FDA approved for management of hypertension. In addition, this work may reveal more accurate methods of early ALS diagnosis, through evaluation of the reflex responses from the leg muscles.

描述（由申请人提供）：本研究将检查来自家族ALS的小鼠模型SOD1G93A小鼠的运动神经元内固有和突触兴奋性的产后发展。 ALS是一种缓慢进展的疾病，其标志是运动神经元的丧失，导致瘫痪，最后死亡。容易受到ALS的运动神经元的细胞内钙（Ca2+）的缓冲能力低，并且通过过度Ca2+进入的兴奋性毒性是ALS中神经变性的可能机制。这项研究将检查在两个主要途径中成熟过程中的变化，可能会发生过多的Ca2+进入：突触激发增加和/或运动神经元的内在兴奋性增加。固有的兴奋性是由持续的Na+通道（NAP）和CAV1.3 Ca2+通道介导的，它们产生了持续的内向电流（PIC）。 Riluzole是唯一获得ALS的FDA批准的药物，以两种方式工作，阻塞NAP并减少突触前谷氨酸释放。不幸的是，Riluzole随着时间的流逝失去了有效性，因此需要对ALS的其他潜在治疗进行探索。 Isradipine，一种有效阻断CAV1.3 Ca2+通道的二氢丙氨酸拮抗剂将被应用，并在新生儿，少年和成年小鼠中评估运动神经元的兴奋性。尽管PIC的主要部分是在年轻大鼠中午睡的，但在成熟期间，Ca2+的贡献增加到约50％。 ALS的成年发作可能与从Na+到Ca2+介导的PIC的转变有关。在帕金森氏病中，Na+依赖性的起搏器活性的成熟在NIGRA神经元中对CAV1.3-介导的成人活性会导致变性，并且如果在长期暴露于Isradipine的成年人中，这些神经元会引起Na+依赖性活性，这些神经元对这些神经元的暴露较少，那么这些神经元就对这种疾病的易感性较小。在SOD1G93A小鼠的衰老运动神经元中可能会发展出类似的Ca ++敏感性，Isradipine可能是一种有效的治疗方法。因此，我建议研究固有和突触的兴奋性，包括正常和SOD1G93A小鼠中的som和dendritic Ca2+水平，以及短期和长期以伊拉迪平暴露对新生儿的SOD1G93A小鼠在SOD1G93A小鼠中的短期和长期Isradipine暴露的影响。我将使用全细胞贴片夹和尖锐的电极内记录从腰部和s骨运动神经元记录，并使用多光子成像和Ca2+敏感染料在所有时间点检查树突状Ca2+膨胀。这项研究将评估针对ALS，Isradipine的新治疗方法，Isradipine是一种目前批准用于管理高血压的药物。此外，通过评估腿部肌肉的反射反应，这项工作可能揭示了更准确的ALS诊断方法。