Plasticity of GABA input to VTA dopamine neurons in opioid use disorders

阿片类药物使用障碍中 VTA 多巴胺神经元 GABA 输入的可塑性

基本信息

批准号：
10512049
负责人：
Michael J Beckstead
金额：
--
依托单位：
OKLAHOMA CITY VA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-10-01 至 2025-09-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10512049
关键词：
Ablation Abstinence Affect Affinity Chromatography Aging Alleles Area Astrocytes Attention Behavior Behavioral Bioinformatics Brain Breeding Cell Nucleus Chest Clinical Code Cre lox recombination system Cues DNA Data Dependovirus Development Disease Disinhibition Electrophysiology (science)Enterobacteria phage P1 Cre recombinase Family member Female Fentanyl Gene Expression General Population Genes Genetic Glean Hypothalamic structure Individual Injections Intake Knock-out Knowledge Label Lateral Link LoxP-flanked allele Maintenance Measures Mediating Molecular Mus Neurons Neurotensin Neurotensin Receptors Neurotransmitters Nociception Nuclear Nucleic Acids Nucleus Accumbens Opioid Opioid Receptor Overdose Pain Pain management Pathway interactions Peptides Pharmaceutical Preparations Physiological Procedures Property Psychological reinforcement Public Health Quality of life RNA Rattus Receptor Signaling Recording of previous events Relapse Ribosomes Risk Role Self Administration Signal Transduction Site Slice Source Suicide Synapses Synaptic Transmission Synaptic plasticity System Techniques Testing Titrations Translating Ventral Tegmental Area Veterans Viral Virus Withdrawal Work Writing adverse outcome aldehyde dehydrogenase 1 analog cell type chronic pain management designer receptors exclusively activated by designer drugs dopamine transporter dopaminergic neuron drug reinforcement epigenomics experience experimental study gamma-Aminobutyric Acid gene interaction improved innovation male mouse genetics mu opioid receptors neuronal excitability neurophysiology new therapeutic target novel opioid abuse opioid epidemic opioid exposure opioid use opioid use disorder optogenetics patch clamp prescription opioid presynaptic receptor remifentanil side effect suicidal risk tool transcriptome transcriptomics treatment strategy vesicular GABA transporter

项目摘要

Despite their dangers, the number of opioid prescriptions written for veterans has increased sharply since 2000, and veterans are more prone than the general population to both suicide and the development of use disorders following opioid treatment. Target receptors for opioids are widely expressed throughout the brain and periphery, but their reinforcing properties are largely mediated by their action in mesocorticolimbic areas such as the ventral tegmental area (VTA) and the nucleus accumbens (NAc). In the VTA, activation of presynaptic mu-opioid receptors is known to blunt release of the inhibitory neurotransmitter GABA, thus “disinhibiting” dopamine neuron activity. Preliminary work has established that the modulatory peptide neurotensin can activate presynaptic neurotensin 1 receptors (NtsR1) to enhance GABA release in the VTA. While this novel form of synaptic plasticity would be expected to directly counteract the effects of opioids, it is not known how repeated opioid exposure interacts with neurotensin effects on GABA signaling. Opioids and neurotensin are both known to modulate pain; however, there are significant gaps in our knowledge of how these compounds interact at the synaptic and circuit level in the VTA to affect drug reinforcement. Improved treatments for opioid use disorders are desperately needed, both for the general population but also for aging veterans that will increasingly develop painful conditions that require long-term treatment. The proposed studies are necessary to determine the feasibility of targeting the neurotensin system to modulate reinforcement and relapse in individuals that no longer can control their opioid intake. We will combine brain slice electrophysiology and cell type-specific molecular techniques with self- administration of the opioid remifentanil in mice to explore these issues. The use of operant self-administration in mice offers several key advantages: mice are able to titrate their intake based on individual sensitivity, and using mice instead of rats opens up the powerful tools of mouse genetics (i.e., Cre-lox technology) to experimental manipulations. The hypothesis to be tested is that a history of remifentanil self-administration decreases neurotensin-induced enhancement of GABA release in the NAc  VTA circuit, removing a critical break on dopamine neuron excitability during drug intake to increase reinforcement. Experiments in Aim 1 will identify the sensitivity of individual GABA inputs in the VTA to neurotensin, and determine how plasticity is affected by remifentanil self-administration as well as following a forced abstinence. Experiments in Aim 2 will use chemogenetics to activate specific GABA inputs to determine their effect on remifentanil self-administration behavior and cue responding following a forced abstinence. A novel cell type-specific neurotensin receptor knockout will provide additional information on the role of specific cell types on opioid self-administration. Experiments in Aim 3 will use a discovery approach to determine transcriptomic and epigenomic alterations following remifentanil self-administration in single cell types of the VTA. This will be done with several novel NuTRAP (Nuclear Tagging and Translating Ribosome Affinity Purification) mouse lines under the control of Cre recombinase that allow for labeling and isolation of both DNA and RNA from specific cell types. Improved strategies are desperately needed to improve the quality of life for veterans at risk of adverse consequences following opioid treatment. Data obtained will delineate the behavioral and physiological interactions between GABA input to the VTA, neurotensin signaling, and opioid exposure, and identify novel gene and receptor targets for exploration as treatments for opioid use disorders.

尽管存在危险，但自那以来，为退伍军人开出的阿片类药物处方数量急剧增加 2000 年，退伍军人比一般人群更容易自杀，并且发展使用阿片类药物治疗后的疾病在整个大脑中广泛表达。和周围，但它们的增强特性很大程度上是由它们在中皮质边缘区域的作用介导的例如腹侧被盖区 (VTA) 和伏隔核 (NAc) 在 VTA 中，激活已知突触前 mu-阿片受体会减弱抑制性神经递质 GABA 的释放，因此 “去抑制”多巴胺神经元活性。神经降压素可以激活突触前神经降压素 1 受体 (NtsR1)，以增强 VTA 中 GABA 的释放。虽然这种新型突触可塑性有望直接抵消阿片类药物的作用，但它是目前尚不清楚重复暴露阿片类药物如何与神经降压素对阿片类药物和 GABA 信号传导的影响相互作用。众所周知，神经降压素都可以调节疼痛；然而，我们对如何调节疼痛的了解还存在很大差距。这些化合物在 VTA 的突触和回路水平上相互作用，影响药物强化。对于普通人群和老龄化来说，迫切需要治疗阿片类药物使用障碍退伍军人将越来越多地出现需要长期治疗的痛苦状况。需要进行研究以确定针对神经降压素系统进行调节的可行性不再能够控制阿片类药物摄入量的个体的强化和复发。我们将脑切片电生理学和细胞类型特异性分子技术与自我在小鼠中施用阿片类药物瑞芬太尼来探索这些问题。小鼠实验具有几个关键优势：小鼠能够根据个体敏感性调整摄入量，并且使用小鼠代替大鼠开启了小鼠遗传学的强大工具（即 Cre-lox 技术）待检验的假设是瑞芬太尼自我给药史。减少 NAc → VTA 回路中神经降压素诱导的 GABA 释放增强，消除关键的目标 1 中的实验将在药物摄入过程中破坏多巴胺神经元的兴奋性。确定 VTA 中单个 GABA 输入对神经降压素的敏感性，并确定可塑性如何受瑞芬太尼自我给药以及目标 2 中的强制戒断实验的影响。使用化学遗传学激活特定的 GABA 输入以确定其对瑞芬太尼自我给药的影响强制戒酒后的行为和提示反应。基因敲除将提供有关特定细胞类型对阿片类药物自我给药的作用的更多信息。目标 3 中的实验将使用发现方法来确定转录组和表观基因组的改变在对 VTA 的单细胞类型进行瑞芬太尼自我给药后，这将通过几篇小说来完成。 Cre 控制下的 NuTRAP（核标记和翻译核糖体亲和纯化）小鼠品系允许从特定细胞类型中标记和分离 DNA 和 RNA 的重组酶。迫切需要采取策略来改善面临不良后果风险的退伍军人的生活质量阿片类药物治疗后获得的数据将描述之间的行为和生理相互作用。 GABA 输入至 VTA、神经降压素信号传导和阿片类药物暴露，并识别新基因和受体探索治疗阿片类药物使用障碍的目标。