Effect of ethanol on Bergmann glia Ca2+ dynamics during motor behavior

乙醇对运动行为过程中伯格曼胶质细胞 Ca2 动力学的影响

• 批准号: 8837394
• 负责人: Martin Paukert
• 金额: $ 7.25万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8837394
• 关键词: AMPA Receptors; Acute; Adrenergic Receptor; Affect; Air; Alcohol abuse; Alcohol withdrawal syndrome; Animals; Astrocytes; Ataxia; Behavior; Behavioral; Brain; Cells; Cerebellar cortex structure; Cerebellum; Chemosensitization; Chronic; Communication; Data; Dependence; Development; Dose; Elements; Equilibrium; Ethanol; Event; Exposure to; Flare; Glutamate Receptor; Glutamates; Goals; Health; High Prevalence; Image; Injection of therapeutic agent; Investigation; Ion Channel; Lead; Light; Link; Locomotion; Measures; Mediating; Membrane; Monitor; Motor; Mus; Neuroglia; Neurons; Norepinephrine; Pathway interactions; Play; Poison; Process; Property; Purkinje Cells; Recreational Drugs; Resolution; Rest; Role; Signal Transduction; Slice; Societies; Symptoms; Synapses; Testing; Therapeutic; Time; Transgenic Mice; Tremor; Walking; Withdrawal; alcohol effect; alcohol exposure; alertness; dosage; drinking water; granule cell; in vivo; infancy; information processing; insight; motor control; neurochemistry; noradrenergic; novel; patch clamp; receptor; research study; response; socioeconomics; two-photon

DESCRIPTION (provided by applicant): Alcohol abuse has the highest prevalence and the greatest socioeconomic impact on western societies among the abused substances. Ethanol is one of the most toxic substances for the cerebellum, acutely leading to ataxic motor behavior. The circuitry in the cerebellar cortex that enables adaptive motor responses utilizes a close interaction between Bergmann glia (BG) and neuronal elements. BGs can respond to locomotion with widespread, coordinated Ca2+ transients ("flares") possibly influencing the excitability of neurons. Remarkably, not every locomotion event leads to flares, and in order to understand their function it is necessary to uncover the cellular mechanisms that link flares to behavioral context and modulate their intensity. Ethanol sensitizes GABAA receptors and reduces activation of excitatory ion channels. Chronic ethanol exposure leads to adaptation of the responsiveness of these neurochemical pathways which allows the cerebellum and brain to operate fairly normal. Withdrawal from ethanol unmasks these adaptations leading to severe tremor and other symptoms. It is not known whether ethanol has an effect on BGs despite many membrane receptors being shared among glia and neurons. To shed light on this important question, the proposed studies will use transgenic mice which express the genetically encoded Ca2+ indicator GCaMP3 selectively in all BGs, and Ca2+ responses will be analyzed with two-photon imaging while the animal is walking or resting on a linear treadmill. This approach offers the unprecedented opportunity to investigate BG function with cellular resolution over the time course of months. Our preliminary studies revealed that flares are initiated when locomotion coincides with a state of increased alertness, induced by an air puff to the flank of the animal. Preliminary in vivo pharmacological investigations support this hypothesis, suggesting that flares require activation of alpha1-adrenoceptors. Furthermore, we found that acute ethanol exposure at locomotion-relevant dosages suppresses flares reversibly. The overall goal of this proposal is to test the hypothesis that the inhibition of flares by acute ethanol exposure corresponds with ataxic motor behavior, and that during withdrawal from chronic ethanol exposure, enhancement of flares corresponds with tremor. 1), the effect of different dosages of acute ethanol injections on flares and motor coordination (rotarod, balance beam) will be investigated. In acute cerebellar slices the effect of ethanol on BG AMPA receptor currents and norepinephrine induced Ca2+ elevations will be investigated. 2), flares and tremor (EMG) will be monitored during chronic ethanol exposure and upon withdrawal. If flares are enhanced during withdrawal, it will be determined whether pharmacologically resetting flares to normal intensity will reduce tremor. Upon completion of the proposed studies the role of BG flares during normal cerebellar motor control and under the influence of ethanol will be defined in depth. The studies have the potential to lead the way towards novel, more specific treatments of ethanol withdrawal.

描述(申请人提供)：在被滥用的物质中，酒精滥用的流行率最高，对西方社会的社会经济影响最大。乙醇是对小脑毒性最大的物质之一，会剧烈地导致共济失调运动行为。小脑皮质中实现自适应运动反应的电路利用了Bergmann胶质细胞(BG)和神经元元素之间的密切相互作用。BGS可以通过广泛的、协调的钙瞬变(“耀斑”)来响应运动，可能影响神经元的兴奋性。值得注意的是，并不是每个运动事件都会导致耀斑，为了了解它们的功能，有必要揭示将耀斑与行为背景联系起来并调节其强度的细胞机制。乙醇能敏化GABAA受体，减少兴奋性离子通道的激活。长期接触酒精会导致这些神经化学通路的反应性适应，从而使小脑和大脑能够相当正常地运行。戒掉乙醇会暴露出这些适应，导致严重的震颤和其他症状。尽管神经胶质细胞和神经元之间有许多共同的膜受体，但乙醇是否对BGS有影响尚不清楚。为了阐明这个重要的问题，拟议的研究将使用在所有BGS中选择性表达遗传编码的钙指示剂GCaMP3的转基因小鼠，当动物在线性跑步机上行走或休息时，将用双光子成像分析钙的反应。这种方法提供了前所未有的机会，在几个月的时间过程中研究细胞分辨率的BG功能。我们的初步研究表明，耀斑是在运动时启动的，与动物侧翼的一次喷气引起的警觉状态相一致。初步的体内药理学研究支持这一假说，认为耀斑需要激活α1肾上腺素受体。此外，我们发现运动相关剂量的急性酒精暴露可逆地抑制耀斑。这项建议的总体目标是检验这样一种假设，即急性乙醇暴露对耀斑的抑制与共济失调运动行为相对应，而在慢性乙醇暴露戒断期间，耀斑的增强与震颤相对应。1)，研究不同剂量的急性注射乙醇对耀斑和运动协调性(转杆、平衡木)的影响。在急性小脑切片上，将研究乙醇对BG-AMPA受体电流和去甲肾上腺素引起的钙升高的影响。2)，在慢性酒精暴露期间和戒断后将监测耀斑和震颤(EMG)。如果照明弹在撤退过程中增强，将确定通过药物将照明弹重新设置为正常强度是否会减少震颤。在拟议的研究完成后，将深入确定BG信号在正常小脑运动控制和乙醇影响下的作用。这些研究有可能引领人们走向更新颖、更具体的乙醇戒断治疗方法。