Optical imaging of dopamine kinetics in prefrontal cortex of normal and schizophrenia model mice

项目总结 精神分裂症是一种令人衰弱的终生精神疾病，全球患病率为1%。它的特点是 通过积极的症状(妄想、幻觉、思维混乱)，消极的症状(平淡的情感， 快感缺乏)和认知症状(执行功能、注意力和工作方面的缺陷 内存(WM))。虽然阳性症状可以用抗精神病药物有效地控制，但没有 对阴性和认知症状的治疗。 最近对精神分裂症患者的PET成像证实存在皮质多巴胺(DA)缺陷 在与地方检察官提出挑战后，释放了毒品安非他明(Amph)。长期以来，大脑皮层多巴胺的这种不足 被认为在精神分裂症的阴性和认知症状的病理中起关键作用，包括 WM中的赤字。由于缺乏研究单一突触分辨率的神经传递的工具 VIVO，这种赤字的性质还有待确定。 为了用单一突触分辨率研究体内DA神经传递，我们优化了一种新的工具 用于对小鼠进行体内多光子成像。荧光假神经递质(FFN)是一种荧光底物 对于多巴胺转运体(DAT)、去甲肾上腺素转运体(NET)和囊泡单胺转运体 (VMAT)，它们被吸收到轴突的突触前突触，在那里它们随后被加载到 突触前小泡。FFN以前曾用于急性脑片实验，以允许确定 然而，在突触释放的动力学中，它们在体内的应用是一个未发表的应用。我们已经使用了FFN 成像活体大脑皮层中儿茶酚胺的神经传递。在这个项目中，我们将利用多光子 FFN和GCaMP6f在体显像记录大鼠中脑突触前皮质终末的DA释放 WT和精神分裂症模型小鼠的内侧前额叶皮质在AMPH诱导的电诱发过程中， 并在WM的一项任务中自发释放。 该建议实现了一种新的方法来检查体内释放的DA在WT和两个小鼠模型 精神分裂症首次测量在AMPH诱导释放和 WM的一项任务。阐明精神分裂症小鼠模型多巴胺缺陷的机制可能提供 精神分裂症患者发生变化的关键翻译信息，并可能揭示新的靶点 有助于未来的治疗策略。

PROJECT SUMMARY Schizophrenia is a debilitating lifelong psychiatric disorder with a worldwide prevalence of 1%. It is characterized by positive symptoms (delusions, hallucinations, disorganized thinking), negative symptoms (flattened affect, anhedonia, paucity of speech) and cognitive symptoms (defects in executive function, attention, and working memory (WM)). While the positive symptoms can be effectively managed with antipsychotic drugs, there are no treatments for the negative and cognitive symptoms. Recent PET imaging of schizophrenic patients has confirmed that there is a cortical dopamine (DA) deficit following a challenge with the DA releasing drug amphetamine (AMPH). This deficit in cortical DA has long been thought to play a critical role in the pathology of the negative and cognitive symptoms of schizophrenia, including the deficit in WM. Due to a lack of tools with which to study neurotransmission with single synapse resolution in vivo, the nature of this deficit has yet to be determined. In order to study DA neurotransmission in vivo with single synapse resolution, we have optimized a novel tool for in vivo multiphoton imaging of mice. Fluorescent false neurotransmitters (FFNs) are fluorescent substrates for the DA transporter (DAT), the norepinephrine transporter (NET), and the vesicular monoamine transporter (VMAT), that are taken up into the presynaptic boutons of axons where they are subsequently loaded into presynaptic vesicles. FFNs have previously been used in acute brain slice experiments to allow determination of the kinetics of synaptic release, however, their use in vivo is an unpublished application. We have used FFNs to image catecholamine neurotransmission in the cortex in vivo. For this project, we will utilize multiphoton imaging in vivo of FFNs and GCaMP6f, to record DA release from presynaptic mesocortical terminals in the medial prefrontal cortex of WT and schizophrenia model mice both during AMPH induced electrically evoked, and spontaneous release and during a task of WM. This proposal implements a novel method to examine DA release in vivo in WT and two mouse models of schizophrenia to provide the first measurement of in vivo kinetics of DA during both AMPH induced release and a task of WM. Elucidating the mechanism underlying DA deficits in schizophrenia mouse models may provide key translational information for the changes that occur in schizophrenic patients and may reveal new targets to aid future therapeutic strategies.