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（由申请人提供）：酗酒的患病率最高，社会经济对虐待物质中西方社会的影响最大。乙醇是小脑最有毒的物质之一，急性导致了共济失调的运动行为。小脑皮层中的电路使自适应运动反应采用了Bergmann Glia（BG）和神经元元素之间的紧密相互作用。 BG可以用广泛的，协调的Ca2+瞬变（“耀斑”）对运动作出反应，可能会影响神经元的兴奋性。值得注意的是，并非每个运动事件都会导致耀斑，为了了解其功能，有必要揭示将耀斑与行为环境联系起来并调节其强度的细胞机制。乙醇使GABAA受体敏感并减少兴奋性离子通道的激活。慢性乙醇暴露会导致这些神经化学途径的反应能力适应，这使小脑和大脑可以相当正常。从乙醇中提取这些适应，导致严重的震颤和其他症状。尽管有许多膜受体在神经胶质和神经元之间共享，但尚不知道乙醇是否对BGS有效。为了阐明这个重要问题，拟议的研究将使用转基因小鼠在所有BG中选择性地表达遗传编码的Ca2+指标GCAMP3，而Ca2+反应将通过两光子成像进行分析，而动物正在行走或在线性跑步机上行走或休息。这种方法提供了前所未有的机会，可以在几个月的时间过程中使用蜂窝分辨率调查BG功能。我们的初步研究表明，当运动与机敏的增强状态相吻合时，会引发耀斑，这是由于动物侧面的空气泡芙引起的。初步体内药理学研究支持了这一假设，表明耀斑需要激活α1-肾上腺素受体。此外，我们发现与运动相关剂量的急性乙醇暴露会可逆地抑制耀斑。该提案的总体目标是检验以下假设：急性乙醇暴露对耀斑的抑制与共同运动的行为相对应，并且在退出慢性乙醇暴露期间，耀斑的增强与震颤相对应。 1）将研究不同剂量的急性乙醇对耀斑和运动配位的影响（Rotarod，Balance Beam）。在急性小脑切片中，将研究乙醇对BG AMPA受体电流和去甲肾上腺素诱导的Ca2+升高的影响。 2），在慢性乙醇暴露期间和退出后将监测耀斑和震颤（EMG）。如果在戒断过程中增强了耀斑，则将确定药理学将耀斑重置为正常强度是否会降低震颤。拟议的研究完成后，将深入定义BG耀斑在正常小脑运动控制中并在乙醇的影响下的作用。这些研究有可能引导新颖，更具体的乙醇戒断治疗方法。