Synaptic mechanisms underlying reward seeking and compulsive drug use

奖励寻求和强迫性药物使用的突触机制

• 批准号: 10018360
• 负责人: Veronica A Alvarez
• 金额: $ 244.66万
• 依托单位: NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10018360
• 关键词: A kinase anchoring protein; Acute; Addictive Behavior; Affect; Agonist; Alcohol abuse; Alcohol consumption; Alcohols; Animals; Appetitive Behavior; Behavior; Behavioral; C57BL/6 Mouse; Cells; Chemosensitization; Chronic; Cocaine; Cocaine Abuse; Compulsive Behavior; Consummatory Behavior; Consumption; Corpus striatum structure; Corticotropin-Releasing Hormone; Corticotropin-Releasing Hormone Receptors; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Data; Development; Disease; Dopamine; Dopamine D1 Receptor; Dopamine D2 Receptor; Dorsal; Down-Regulation; Drug effect disorder; Drug usage; Environment; Ethanol; Genetic; Globus Pallidus; Goals; Human; Hypersensitivity; In Vitro; Individual; Intake; Interneurons; Journals; Knockout Mice; LRRK2 gene; Laboratories; Link; Locomotion; Mediating; Messenger RNA; Motivation; Mus; Muscarinic Acetylcholine Receptor; Neurobiology; Neurons; Neuropeptides; Neurosciences; Nucleus Accumbens; Outcome; Output; Parkinson Disease; Pathway interactions; Pharmaceutical Preparations; Physiological; Play; Population; Production; Proteins; Psychological reinforcement; Publications; Publishing; Quinine; Receptor Activation; Regulation; Reporting; Research; Response to stimulus physiology; Rewards; Rodent; Role; Sedation procedure; Self Administration; Signal Transduction; Stimulus; Stress; Synapses; Taste Perception; Testing; Transgenic Mice; Ventral Striatum; Vertebral column; alcohol behavior; alcohol exposure; alcohol response; alcohol seeking behavior; alcohol sensitivity; alcohol use disorder; cholinergic; drinking; drug abuse vulnerability; drug of abuse; gene product; in vivo; insight; male; motivated behavior; mouse model; novel; optogenetics; pre-clinical; preference; receptor; resilience; response; sedative; tool; transmission process

Project A: Preclinical mouse model reveals a mechanism linking two known vulnerability factors for alcohol abuse: heightened alcohol stimulation and low striatal dopamine D2 receptors (Study accepted for publication and currently under press in Cell Reports). Alcohol produces both stimulant and sedative effects in humans and rodents. In humans, alcohol abuse disorder is associated with a higher stimulant and lower sedative responses to alcohol. Here we show this association is conserved in mice and demonstrate a causal link with another liability factor: low expression of striatal dopamine D2 receptors (D2Rs). Using transgenic mouse lines, we found that selective loss of D2Rs on striatal medium spiny neurons enhances sensitivity to ethanol stimulation and generates resilience to ethanol sedation. These mice also display higher preference and escalation of ethanol drinking, which continues despite aversive outcomes. We found that striatal D1R activation is required for ethanol stimulation and this signaling is enhanced in mice with low striatal D2Rs. Together, these data demonstrate a link between two vulnerability factors for alcohol abuse and offer evidence for a mechanism where low striatal D2Rs triggers D1R hypersensitivity, ultimately leading to compulsive-like drinking. Project B: Striatal cholinergic interneurons are a novel target of corticotropin releasing factor (CRF) (study published in the Journal of Neuroscience). While the presence of CRF receptors in the dorsal and ventral striatum has been acknowledged, the cellular identity and the functional consequences of the receptor activation is unknown. Here we report that striatal cholinergic interneurons express CRF-R1 receptors and are acutely activated by the neuropeptide CRF that is released in response to salient environmental stimuli. Cholinergic interneurons make less than 1 % of the cells in the striatum but are critical regulators of the striatal circuitry and its output. CRFs fast and potent activation of cholinergic interneurons could then have far reaching behavioral implications across motivated behaviors controlled by the striatum. Summary: Cholinergic interneurons (CINs) are critical regulators of striatal network activity and output. Changes in CIN activity are thought to encode salient changes in the environment and stimulus-response-outcome associations. Here we report that the stress-associated neuropeptide corticotropin releasing factor (CRF) produces a profound and reliable increase in the spontaneous firing of CINs in both dorsal striatum (DS) and nucleus accumbens (NAc) through activation of CRF type 1 receptors (CRF-R1), production of cAMP and reduction in spike accommodation in male mice. The increase of CIN firing by CRF results in the activation muscarinic acetylcholine receptors type 5, which mediate potentiation of dopamine transmission in the striatum. This study provides critical mechanistic insight into how CRF modulates striatal activity and dopamine transmission in the NAc to likely account for CRF facilitation of appetitive behaviors. Project C: Lack of LRRK2, a Parkinsons disease-related protein, promotes compulsive-like and high alcohol intake in mice (study to be submitted for publication). Chronic alcohol exposure alters striatal function and drives compulsive alcohol-seeking despite negative consequences, one of the hallmarks of alcohol use disorders. The striatum plays a central role in goal-directed behaviors and it is thought to undergo long-lasting changes that drive addictive behaviors. We previously found that the Lrrk2 gene is upregulated in the striatum of animals that show inflexible alcohol drinking as defined by high alcohol preference even after its taste-adulteration. The Lrrk2 gene product is an AKAP that regulates PKA availability at spines and it is involved in synaptic modulation in striatal neurons. We hypothesized that the Lrrk2 gene through its modulation of PKA signaling downstream of dopamine D1 receptors (D1R) is involved in facilitating compulsive alcohol taking. To prove this hypothesis, we first tested whether alcohol drinking can modulate Lrrk2 levels in C57BL/6 mice. Using qPCR and RNAscope, we found that alcohol drinking increased mRNA levels for Lrrk2 in the dorsal striatum, in both D1R and D2R-expressing neurons, the two classes of projection neurons in the striatum. Interestingly and contrary to our prediction, alcohol reduced total protein levels for Lrrk2 in the dorsolateral striatum. To assess whether a preexisting downregulation of Lrrk2 protein levels is sufficient to change alcohol drinking, we tested different Lrrk2 cell-specific knockout mice on alcohol drinking tasks and other alcohol-related behaviors. We found that mice lacking Lrrk2 constitutively show enhanced alcohol consumption. Similarly, when the Lrrk2 gene was specifically deleted in D1R neurons, mice showed an increased and persistent alcohol consumption even after quinine adulteration compared to littermate controls. Moreover, these D1-Lrrk2-KO mice consumed more alcohol in an operant self-administration task and showed higher breakpoint, an indication of higher motivation to consume alcohol. Additionally, D1-Lrrk2-KO mice showed enhanced alcohol-induced locomotion, a response that is mediated by dopamine D1R, as well as are more sensitive to a D1-like receptor agonist. These findings suggest that Lrrk2 regulation of PKA activity downstream of D1R in direct-pathway striatal neurons plays an important role in regulating alcohol consummatory behaviors.

项目A：临床前小鼠模型揭示了一种机制，将两个已知的酒精滥用脆弱性因素联系起来：酒精刺激增强和纹状体多巴胺D2受体降低（研究已接受出版，目前正在Cell Reports上出版）。酒精对人类和啮齿动物都有刺激和镇静作用。在人类中，酒精滥用障碍与对酒精的较高刺激和较低镇静反应有关。在这里，我们表明这种关联是保守的小鼠，并证明与另一个责任因素的因果关系：纹状体多巴胺D2受体（D2 Rs）的低表达。使用转基因小鼠系，我们发现，选择性损失的D2 Rs纹状体中型多刺神经元增强敏感性乙醇刺激，并产生弹性乙醇镇静。这些小鼠还表现出更高的偏好和酒精饮用的升级，尽管结果令人厌恶，但这种情况仍在继续。我们发现，纹状体D1 R激活是乙醇刺激所必需的，并且这种信号在纹状体D2 R低的小鼠中增强。总之，这些数据表明了酒精滥用的两个脆弱性因素之间的联系，并为低纹状体D2 R触发D1 R超敏反应，最终导致强迫性饮酒的机制提供了证据。 项目B：纹状体胆碱能中间神经元是促肾上腺皮质激素释放因子（CRF）的新靶点（研究发表在《神经科学杂志》上）。虽然背侧和腹侧纹状体中存在CRF受体已被承认，但受体激活的细胞身份和功能后果尚不清楚。在这里，我们报告说，纹状体胆碱能中间神经元表达CRF-R1受体，并急性激活的神经肽CRF，释放响应显着的环境刺激。胆碱能中间神经元在纹状体中的细胞中占不到1%，但却是纹状体回路及其输出的关键调节器。CRF对胆碱能中间神经元的快速有效激活可能对纹状体控制的动机行为产生深远的行为影响。胆碱能中间神经元（CINs）是纹状体网络活动和输出的关键调节因子。CIN活动的变化被认为编码了环境和刺激-反应-结果关联的显著变化。在这里，我们报告说，应激相关的神经肽促肾上腺皮质激素释放因子（CRF）产生一个深刻的和可靠的增加自发放电的CINs在背侧纹状体（DS）和背侧纹状体核（NAc）通过激活CRF 1型受体（CRF-R1），生产cAMP和减少尖峰的住宿在雄性小鼠。CRF增加CIN放电导致毒蕈碱乙酰胆碱受体5型活化，其介导纹状体中多巴胺传递的增强。这项研究提供了关键的机制洞察CRF如何调节纹状体活动和多巴胺在NAc的传输，可能占CRF促进食欲行为。 项目C：缺乏LRRK 2，一种帕金森病相关蛋白，促进小鼠的强迫性和高酒精摄入（研究提交出版）。长期酒精暴露会改变纹状体功能，并驱使强迫性酒精寻求，尽管有负面后果，这是酒精使用障碍的标志之一。纹状体在目标导向行为中起着核心作用，并且被认为经历了驱动成瘾行为的长期变化。我们以前发现，Lrrk 2基因在动物的纹状体中上调，这些动物表现出不灵活的饮酒，即使在其味道掺假后也表现出高酒精偏好。Lrrk 2基因产物是一种AKAP，其调节棘上PKA的可用性，并参与纹状体神经元的突触调节。我们假设Lrrk 2基因通过调节多巴胺D1受体（D1 R）下游的PKA信号传导参与促进强迫性饮酒。为了证明这一假设，我们首先测试了饮酒是否可以调节C57 BL/6小鼠中的Lrrk 2水平。使用qPCR和RNAscope，我们发现饮酒增加了背侧纹状体中Lrrk 2的mRNA水平，在D1 R和D2 R表达神经元中，纹状体中的两类投射神经元。有趣的是，与我们的预测相反，酒精降低了背外侧纹状体中Lrrk 2的总蛋白水平。为了评估预先存在的Lrrk 2蛋白水平下调是否足以改变饮酒，我们测试了不同的Lrrk 2细胞特异性敲除小鼠的饮酒任务和其他酒精相关行为。我们发现缺乏Lrrk 2的小鼠表现出增强的酒精消耗。类似地，当Lrrk 2基因在D1 R神经元中被特异性删除时，与同窝对照相比，即使在奎宁掺假后，小鼠也表现出增加和持续的酒精消耗。此外，这些D1-Lrrk 2-KO小鼠在操作性自我给药任务中消耗更多的酒精，并显示出更高的断点，这表明消耗酒精的动机更高。此外，D1-Lrrk 2-KO小鼠表现出增强的酒精诱导的运动，这是一种由多巴胺D1 R介导的反应，并且对D1样受体激动剂更敏感。这些发现表明，Lrrk 2调节PKA活性下游的D1 R在直接通路纹状体神经元中起着重要的作用，在调节酒精消费行为。