Mechanisms underlying increased cocaine self-administration in Npas2 knockout mice

Npas2 敲除小鼠可卡因自我给药增加的机制

基本信息

批准号：
9922270
负责人：
Lauren Marie DePoy
金额：
$ 6.74万
依托单位：
UNIVERSITY OF PITTSBURGH AT PITTSBURGH
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-05-01 至 2021-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9922270
关键词：
Acute Affect Behavior Brain Cellular Structures Chronic Circadian Dysregulation Circadian Rhythms Clozapine Cocaine Coupled Cytoskeletal Proteins Data Dendritic Spines Development Female Future Gene Expression Genes Genetic Polymorphism Genetic Transcription Glutamates Homologous Gene Human Image Intake Knock-out Knockout Mice Label Lead Light Long-Term Effects Measures Molecular Motivation Mus Mutation Neurons Nucleus Accumbens Oxides Pattern Periodicity Pharmaceutical Preparations Pharmacology Play Property Prosencephalon Proteins Public Health Rattus Regulation Relapse Reporting Research Rewards Rodent Role Self Administration Sleep Sleep Fragmentations Stains Structure Substance Addiction Symptoms Synapses Tissues Tomatoes Training Volition Wild Type Mouse Withdrawal addiction base cell type cellular targeting circadian circadian pacemaker cocaine exposure cocaine relapse common symptom conditioned place preference density designer receptors exclusively activated by designer drugs glutamatergic signaling insight knock-down male molecular clock neurotransmission nonhuman primate novel pleasure preference relating to nervous system transcription factor transmission process

项目摘要

Project Summary/Abstract Disruptions in circadian rhythms are not only a common symptom of addiction, but also contribute to the development of substance dependence. However, the mechanisms by which circadian dysregulation impacts addiction are largely unknown. Mutations and polymorphisms in circadian clock genes have been shown to augment addiction-related behaviors in rodents and are associated with vulnerability to substance dependence in humans. CLOCK and NPAS2 are key regulators of the molecular clock. NPAS2 is similar to CLOCK in structure and function, however, there are key differences in the expression patterns of these proteins. CLOCK is ubiquitously expressed in the brain, while NPAS2 is highly, rhythmically expressed in the nucleus accumbens (NAc) and is enriched in D1 expressing neurons. Our lab found that while a mutation in the Clock gene increases cocaine preference and self-administration in mice, Npas2 knockout (KO) mice have decreased cocaine preference. These results suggest that NPAS2 and CLOCK play unique roles in regulating reward-related behaviors. However, my recent data show that despite a reduction in cocaine preference, Npas2 KO mice have increased cocaine self-administration. Instead of measuring cocaine preference, which is based on the pharmacology of cocaine and its pleasurable effects, self-administration measures active, volitional, chronic drug intake, as well as the reinforcing and motivational properties of cocaine, and relapse-like behavior. Since preference and drug intake are fundamentally different measures, the mechanisms by which NPAS2 affects these reward-related behaviors are likely unique. However, further research is needed to understand how alterations in circadian genes might be exacerbating drug intake. This proposal will focus on identifying possible cellular and molecular mechanisms underlying increased drug intake in Npas2 KO mice. Recently our lab found that Npas2 knockdown in the NAc increases glutamatergic transmission and AMPA/NMDAR ratio specifically in D1 neurons. Cocaine exposure alters glutamatergic transmission in the NAc and this is known to regulate self- administration and reinstatement. In addition, Npas2 KO increases dendritic spine density in the NAc, which could contribute to this increase in transmission. These results suggest that changes in glutamatergic neurotransmission could underlie increased cocaine self-administration in Npas2 KO mice. In this proposal, I aim to determine how NPAS2 regulates D1 glutamatergic signaling and whether increased transmission in the NAc contributes to increased cocaine self-administration in Npas2 KO mice. In order to understand how glutamatergic signaling is altered, I will first determine how Npas2 KO affects cellular structure and targeted RNA expression in NAc D1 neurons. Subsequently, I will attempt to normalize self-administration in Npas2 KO mice by inhibiting D1 NAc neurons. Together, these aims will begin to identify potential cellular and molecular mechanisms underlying the complicated role of NPAS2 in reward.

项目摘要/摘要昼夜节律的干扰不仅是成瘾的常见症状，而且有助于依赖物质的发展。但是，昼夜节律失调影响的机制成瘾基本上是未知的。昼夜节律基因中的突变和多态性已显示为增强啮齿动物中与成瘾相关的行为，与依赖物质依赖性有关在人类中。时钟和NPAS2是分子时钟的关键调节剂。 NPAS2与时钟相似但是，结构和功能，这些蛋白质的表达模式存在关键差异。钟在大脑中无处不在，而NPAS2在伏隔核中有节奏表达（NAC），并富含D1表达神经元。我们的实验室发现，虽然时钟基因中的突变增加在小鼠中可卡因的偏好和自我给药，NPAS2敲除（KO）小鼠可卡因降低偏爱。这些结果表明NPAS2和时钟在调节奖励相关的方面起着独特的作用行为。但是，我最近的数据表明，尽管可卡因偏好降低了，但NPAS2 KO小鼠的增加可卡因自我管理。而不是测量可卡因偏好，这是基于可卡因的药理学及其令人愉悦的效果，自我管理措施活跃，自愿性，慢性药物摄入量，以及可卡因的增强和动机性和类似复发的行为。自从偏好和药物摄入从根本上是不同的措施，NPAS2影响的机制这些与奖励相关的行为可能是独一无二的。但是，需要进一步的研究来了解如何昼夜节律的改变可能会加剧药物摄入量。该建议将重点识别可能 NPAS2 KO小鼠的药物摄入量增加的细胞和分子机制。最近我们的实验室发现 NAC中的NPAS2敲低会增加谷氨酸能的传播和AMPA/NMDAR比率。 D1神经元。可卡因暴露会改变NAC中的谷氨酸能传播，这众所周知可以调节自我管理和恢复。此外，NPAS2 KO增加了NAC中的树突状脊柱密度，该密度可能有助于这种传播的增加。这些结果表明谷氨酸能的变化神经传递可能是在NPAS2 KO小鼠中增加可卡因自我给药的基础。在这个建议中，我旨在确定NPAS2如何调节D1谷氨酸能信号传导以及是否增加 NAC有助于增加可卡因在NPAS2 KO小鼠中的自我管理。为了了解如何谷氨酸能信号改变了，我将首先确定NPAS2 KO如何影响细胞结构和靶向RNA NAC D1神经元中的表达。随后，我将尝试在NPAS2 KO小鼠中归一化自我给药通过抑制D1 NAC神经元。这些目标在一起将开始鉴定潜在的细胞和分子 NPAS2在奖励中的复杂作用的基础机制。