Mechanisms underlying opposing neuronal responses to brief vs. prolonged dopamine

神经元对短暂多巴胺和长时间多巴胺反应相反的机制

• 批准号: 8210997
• 负责人: Deborah Jean Baro
• 金额: $ 32.52万
• 依托单位: GEORGIA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-05 至 2013-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8210997
• 关键词: American; Binding; Biochemical; CREB1 gene; Characteristics; Chronic; Cocaine; Confocal Microscopy; Cost of Illness; Crustacea; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclic AMP-Responsive DNA-Binding Protein; Dominant-Negative Mutation; Dopamine; Dopamine D1 Receptor; Dopamine D2 Receptor; Dose; Drug abuse; Electrophysiology (science); Global Change; Grant; Hour; Imagery; Ion Channel; Ions; Kv4 channel; Lead; Learning; Life; Measures; Mediating; Membrane; Memory; Modeling; Modification; Molecular; Molecular Biology; Names; Neurons; Pharmaceutical Preparations; Phosphorylation; Potassium; Principal Investigator; Prize; Process; Reporting; Research; Research Priority; Rewards; Signal Transduction; Societies; Synapses; Techniques; Testing; Transcript; addiction; classical conditioning; cocaine use; density; prevent; programs; response; reuptake; tool; transcription factor

DESCRIPTION (provided by applicant): Drug abuse is a chronic and devastating disease, costing society over 200 billion per year. The problem is widespread; in 2004, over 34 million Americans reported lifetime use of cocaine. One of NIDA's top research priorities is finding drugs to block cocaine's effects, which will require an understanding of the molecular mechanisms of addiction. Persistent use of cocaine leads to maladaptations in reward-related learning such that the drug is prized above all other rewards, and is compulsively sought after and used, despite severe negative consequences (addiction). Cocaine prevents dopamine (DA) reuptake. A single dose of an addictive drug can elevate synaptic DA for hours. It is not clear how repeated, prolonged elevations in [DA] disrupt the normal mechanisms of associative learning and memory. Such processes depend upon the flow of ions through channels in the neuronal membrane (ion currents); therefore, the densities and characteristics of ion channels in the neuronal membrane help to determine the neuron's capacity to engage in mechanisms of learning and memory. Both cocaine and DA are known to alter ion current densities. Perhaps cocaine-induced aberrations in learning and memory are due to changes in ion current densities resulting from prolonged elevations in DA. Elucidating the processes by which prolonged elevations in synaptic DA lead to changes in ion current densities may lead to a deeper appreciation for how addiction usurps the normal mechanisms of reward related learning and memory. The transient potassium current (IA) is important for learning and memory. Kv4 channels mediate IA. Using a model circuit, the crustacean pyloric network, we found that when DA binds to its receptors, D1 and D2, they produce global biochemical signals that have different effects on IA density over the short- and long-term. For example, in response to a brief application of DA, D2 receptors mediate an increase in IA density. On the other hand, a prolonged 4hr. application of DA produces a D2 mediated, persistent decrease in IA density 10-12 hrs. after DA has been removed. This proposal focuses on the mechanism(s) by which brief versus prolonged applications of DA produce opposing effects on IA density. We specifically test the hypothesis that DA induces global changes in [cAMP] that then alter the phosphorylation state of both Kv4 channels and a transcription factor named CREB. Whereas changes in Kv4 channels are relatively short-lived, modifications in CREB activity are long-lived and result in alterations in Kv4 transcript number. Here we propose to use molecular biology and electrophysiology techniques to measure and correlate changes in global [cAMP], IA density and shal transcript number. Furthermore, pharmacological tools will be used to antagonize or mimic global changes in [cAMP] to determine if they underlie the changes in IA density and shal transcript number. Additionally, expression of a dominant-negative CREB protein and visualization of protein kinase A translocation using confocal microscopy will help to determine if CREB is involved in mediating the long-term response. One of NIDA's top research priorities is finding drugs to block cocaine's effects. This will require an understanding of the mechanisms by which cocaine acts. Cocaine causes a prolonged exposure of neurons to dopamine, which in turn causes many alterations to neuronal function. This grant aims to understand the mechanisms by which prolonged dopamine alters neuronal function.

描述（由申请人提供）：药物滥用是一种慢性、毁灭性的疾病，每年给社会造成的损失超过 2000 亿美元。这个问题很普遍； 2004年，超过3400万美国人报告终生吸食可卡因。 NIDA 的首要研究重点之一是寻找阻止可卡因作用的药物，这需要了解成瘾的分子机制。持续使用可卡因会导致与奖励相关的学习适应不良，因此该药物比所有其他奖励都更受重视，并且尽管会产生严重的负面后果（成瘾），但仍会受到强迫性的追捧和使用。可卡因可阻止多巴胺 (DA) 的再摄取。单剂量的成瘾药物可以使突触 DA 升高数小时。目前尚不清楚[DA]的反复、长时间升高如何破坏联想学习和记忆的正常机制。这些过程取决于离子通过神经元膜通道的流动（离子电流）；因此，神经元膜中离子通道的密度和特征有助于确定神经元参与学习和记忆机制的能力。众所周知，可卡因和 DA 都会改变离子电流密度。也许可卡因引起的学习和记忆异常是由于 DA 长期升高导致离子电流密度的变化所致。阐明突触 DA 的长期升高导致离子电流密度变化的过程可能会导致人们更深入地了解成瘾如何篡夺与奖励相关的学习和记忆的正常机制。瞬时钾电流（IA）对于学习和记忆很重要。 Kv4 通道调解 IA。使用甲壳动物幽门网络模型电路，我们发现当 DA 与其受体 D1 和 D2 结合时，它们会产生全局生化信号，这些信号在短期和长期内对 IA 密度产生不同的影响。例如，短暂使用 DA 后，D2 受体会介导 IA 密度增加。另一方面，延长了4小时。 DA 的应用会产生 D2 介导的 IA 密度持续降低 10-12 小时。 DA 被删除后。该提案重点关注 DA 的短暂应用与长期应用对 IA 密度产生相反影响的机制。我们特别测试了以下假设：DA 诱导 [cAMP] 的整体变化，然后改变 Kv4 通道和名为 CREB ​​的转录因子的磷酸化状态。尽管 Kv4 通道的变化相对短暂，但 CREB ​​活性的改变却是长期存在的，并会导致 Kv4 转录本数量的变化。在这里，我们建议使用分子生物学和电生理学技术来测量和关联全局 [cAMP]、IA 密度和 shal 转录本数量的变化。此外，药理学工具将用于拮抗或模拟[cAMP]的整体变化，以确定它们是否是IA密度和shal转录本数量变化的基础。此外，显性失活 CREB ​​蛋白的表达和使用共聚焦显微镜观察蛋白激酶 A 易位将有助于确定 CREB ​​是否参与介导长期反应。 NIDA 的首要研究重点之一是寻找阻断可卡因作用的药物。这需要了解可卡因的作用机制。可卡因会导致神经元长时间暴露于多巴胺，从而导致神经元功能发生许多改变。该资助旨在了解延长多巴胺改变神经元功能的机制。

项目成果

Tonic 5nM DA stabilizes neuronal output by enabling bidirectional activity-dependent regulation of the hyperpolarization activated current via PKA and calcineurin.

• DOI: 10.1371/journal.pone.0117965
• 发表时间: 2015
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Krenz WD;Rodgers EW;Baro DJ
• 通讯作者: Baro DJ

Tonic dopamine induces persistent changes in the transient potassium current through translational regulation.

• DOI: 10.1523/jneurosci.2194-11.2011
• 发表时间: 2011-09-14
• 期刊: The Journal of neuroscience : the official journal of the Society for Neuroscience
• 作者: Rodgers EW;Krenz WD;Baro DJ
• 通讯作者: Baro DJ

Cell specific dopamine modulation of the transient potassium current in the pyloric network by the canonical D1 receptor signal transduction cascade.

细胞特异性多巴胺通过经典 D1 受体信号转导级联调节幽门网络中的瞬时钾电流。

• DOI: 10.1152/jn.00195.2010
• 发表时间: 2010
• 期刊: Journal of neurophysiology
• 影响因子: 2.5
• 作者: Zhang,Hongmei;Rodgers,EdmundW;Krenz,Wulf-DieterC;Clark,MerryC;Baro,DeborahJ
• 通讯作者: Baro,DeborahJ

D(2) receptors receive paracrine neurotransmission and are consistently targeted to a subset of synaptic structures in an identified neuron of the crustacean stomatogastric nervous system.

• DOI: 10.1002/cne.22225
• 发表时间: 2010-02-01
• 期刊: The Journal of comparative neurology
• 作者: Oginsky MF;Rodgers EW;Clark MC;Simmons R;Krenz WD;Baro DJ
• 通讯作者: Baro DJ

Dopaminergic tone persistently regulates voltage-gated ion current densities through the D1R-PKA axis, RNA polymerase II transcription, RNAi, mTORC1, and translation.

• DOI: 10.3389/fncel.2014.00039
• 发表时间: 2014
• 期刊: Frontiers in cellular neuroscience
• 影响因子: 5.3
• 作者: Krenz WD;Parker AR;Rodgers EW;Baro DJ
• 通讯作者: Baro DJ