Retinoic acid, homeostatic plasticity and cocaine craving

视黄酸、稳态可塑性和可卡因渴望

• 批准号: 10320467
• 负责人: Marina Elizabeth Wolf
• 金额: $ 54.55万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10320467
• 关键词: Abstinence; Acute; Area; Attenuated; Brain; Brain region; Cells; Cocaine; Cocaine Dependence; Cocaine Users; Cocaine withdrawal; Cues; Data; Development; Disinhibition; Enterobacteria phage P1 Cre recombinase; Enzymes; Exhibits; Exposure to; Fiber; Glutamates; Hippocampus (Brain); Home; Human; Incubated; Lead; Link; Maintenance; Mediating; Modeling; Neurons; Nucleus Accumbens; Pathway interactions; Permeability; Pharmaceutical Preparations; Phase; Photometry; Population; Proteins; Rattus; Relapse; Role; Saline; Signal Transduction; Synapses; Synaptic Transmission; Synaptic plasticity; Testing; Transgenic Organisms; Translations; Tretinoin; Withdrawal; Work; base; cocaine self-administration; cocaine use; craving; experimental study; falls; knock-down; new therapeutic target; novel; patch clamp; prevent; receptor; response; synthetic enzyme; tool; transmission process

Project Summary We will use the `incubation of craving' model to study a major challenge in treating cocaine addiction, that is, the persistence of vulnerability to cue-induced relapse even after long periods of abstinence. In this model, rats exhibit progressive intensification (incubation) of cue-induced craving after withdrawal from extended-access cocaine self-administration. Incubation of craving also occurs in humans. Previously, we showed that Ca2+- permeable AMPARs (CP-AMPARs; homomeric GluA1) accumulate in synapses on medium spiny neurons (MSN) of the nucleus accumbens (NAc) core after ~30 days of withdrawal. Thereafter, their activation is required for expression of incubated cocaine craving. Thus, understanding CP-AMPAR plasticity may provide clues about how the intensity of craving is regulated. Work from our lab and others has shown that cocaine withdrawal is associated with multiple adaptations that predict reduced activity or Ca2+ signaling in NAc MSN. However, little is known about how this might be linked to CP-AMPAR insertion. A promising candidate is a form of homeostatic plasticity involving retinoic acid (RA) signaling. Work in hippocampal neurons has shown that Ca2+ levels associated with ongoing synaptic transmission are sufficient to suppress RA synthesis. However, after a period of inactivity, RA synthesis is disinhibited. This increases GluA1 translation, enabling a homeostatic increase in synaptic strength via insertion of homomeric GluA1 CP-AMPARs. CP-AMPAR accumulation in the NAc core during incubation of craving may likewise involve reduced Ca2+ (see above) and we recently showed that it is associated with increased GluA1 translation. Based on these similarities to RA-mediated homeostatic plasticity in hippocampus and on other data, we hypothesize that cocaine withdrawal is associated with decreased Ca2+ signaling in MSN, leading to disinhibition of RA synthesis, increased GluA1 translation and increased synaptic levels of homomeric GluA1 CP-AMPARs. Aim 1 will test the relationship between excitatory transmission, RA synthesis, and GluA1 translation in cultured NAc MSN (co-cultured with cortical cells to restore glutamate inputs). Aim 2 will use fiber photometry to test the hypothesis that baseline Ca2+ in NAc core MSN is reduced during cocaine withdrawal, although it may transiently increase during cue-induced seeking tests and this increase may be augmented as incubation of craving occurs. Transgenic rats expressing Cre recombinase in D1 or A2a receptor-positive MSN (A2a is a marker for D2 MSN) will enable both MSN populations to be studied. In Aim 3, whole-cell patch clamp recordings in identified D1 or A2a NAc core MSN will determine if acute manipulation of RA signaling alters CP-AMPAR levels and if protein translation is involved. Then, we will determine if knocking down a critical RA synthetic enzyme in NAc core during cocaine withdrawal attenuates CP-AMPAR accumulation and maintenance of incubated craving after long withdrawal. Conversely, we will knock down the enzyme that degrades RA in saline rats to determine if a long-term increase in RA is sufficient to increase CP-AMPARs. Overall, our studies will use state-of-the-art tools to test a conceptually novel hypothesis for incubation of craving.

项目概要 我们将使用“渴望的孵化”模型来研究治疗可卡因成瘾的一个主要挑战，即 即使在长期禁欲之后，仍然容易受到提示诱发的复发的影响。在这个模型中，大鼠 退出扩展访问后，提示诱发的渴望逐渐增强（孵化） 可卡因自我给药。人类身上也会出现贪欲的酝酿。之前，我们证明了 Ca2+- 可渗透性 AMPAR（CP-AMPAR；同聚 GluA1）在中等多棘神经元的突触中积累 停药约 30 天后伏隔核 (NAc) 核心的 (MSN)。此后，需要激活它们 用于表达孵化的可卡因渴望。因此，了解 CP-AMPAR 可塑性可能提供以下线索： 如何调节渴望的强度。我们实验室和其他实验室的工作表明，可卡因戒断是 与预测 NAc MSN 中活性或 Ca2+ 信号传导降低的多种适应相关。然而，很少 已知这与 CP-AMPAR 插入有何联系。一个有前途的候选者是一种稳态形式 涉及视黄酸（RA）信号传导的可塑性。海马神经元的研究表明 Ca2+ 水平 与正在进行的突触传递相关的物质足以抑制 RA 合成。然而一段时间后 如果不活动，RA 合成就会受到抑制。这增加了 GluA1 的翻译，从而使体内稳态增加 通过插入同聚 GluA1 CP-AMPAR 来增强突触强度。 CP-AMPAR 在 NAc 核心中积累 在渴望的孵化过程中，同样可能涉及减少 Ca2+（见上文），我们最近表明，它是 与 GluA1 翻译增加有关。基于与 RA 介导的稳态可塑性的这些相似性 在海马体和其他数据中，我们假设可卡因戒断与 Ca2+ 减少有关 MSN 中的信号传导，导致 RA 合成去抑制、GluA1 翻译增加和突触增加 同聚 GluA1 CP-AMPAR 的水平。目标 1 将测试兴奋性传递、RA 之间的关系 培养的 NAc MSN 中的合成和 GluA1 翻译（与皮质细胞共培养以恢复谷氨酸输入）。 目标 2 将使用光纤光度测定法来测试 NAc 核心 MSN 中的基线 Ca2+ 在 可卡因戒断，尽管在提示诱导的寻找测试期间它可能会暂时增加，并且这种增加可能会导致 随着渴求的产生而增强。在 D1 或 A2a 中表达 Cre 重组酶的转基因大鼠 受体阳性 MSN（A2a 是 D2 MSN 的标记）将使两个 MSN 群体都能得到研究。在目标 3 中， 确定的 D1 或 A2a NAc 核心 MSN 中的全细胞膜片钳记录将确定是否急性操作 RA 信号传导会改变 CP-AMPAR 水平以及是否涉及蛋白质翻译。然后，我们将确定是否敲击 在可卡因戒断过程中，NAc 核心中关键的 RA 合成酶下降会减弱 CP-AMPAR 的积累 以及长期戒断后维持潜藏的渴望。相反，我们会击倒这种酶 降解盐水大鼠中的 RA，以确定 RA 的长期增加是否足以增加 CP-AMPAR。 总体而言，我们的研究将使用最先进的工具来测试概念上新颖的渴望孵化假设。