High-speed detection of stimulant-induced cortical ACh release

描述(由申请人提供)：本提案重点介绍兴奋剂药物对皮质胆碱能传递的影响。这是由一种理论驱动的，即皮质胆碱能传递的变化介导了被认为有助于成瘾过程中渴望和复发的过度注意偏差。这种对注意力资源的垄断使吸毒者偏向于处理与毒品有关的线索，并降低了评估替代行为和应对策略的可能性。更彻底地了解这些认知变化背后的神经生物学机制，将有助于开发更有效的方法来处理这一重大公共卫生问题。拟议的实验利用一种创新的酶选择性微电极阵列来揭示精神刺激剂(尼古丁和苯丙胺)对皮质神经化学的影响。这些研究旨在验证使用这些微电极作为胆碱能传递的灵敏测量来快速、原位检测细胞外ACh。ACH导出的信号将以远远超过传统技术的时间(即每秒)和空间(即10-20微米)分辨率来确定。我们将首先在麻醉的大鼠身上测试这种电化学方法(以优化几个电化学、神经生物学和程序变量)。在优化了电化学记录的参数后，我们将在清醒的大鼠中验证该方法，在给予精神刺激剂和环境刺激后，这些刺激已经被证明按照更传统的方法增加了皮质ACh的释放。但是，这只是一系列关于药物滥用条件下注意机制的神经化学的重要实验的起点。我们将第一次能够在一个与认知过程一致的时间框架内研究胆碱能传递，这些认知过程与皮质胆碱能传递有关，并被认为是强迫药物使用的基础。以同样的方式，增强的伏安技术，以及对DA阶段释放的关注，揭示了伏隔DA对药物寻找行为的贡献的新视角。ACh和胆碱敏感的微电极阵列将使我们能够测量亚秒时间段和离散区域内的胆碱能传递，以解决成瘾的重要问题。

DESCRIPTION (provided by applicant): This proposal focuses on the effects of stimulant drugs on cortical cholinergic transmission. It is driven by the theory that changes in cortical cholinergic transmission mediate the hyper-attentional biases postulated to contribute to processes of craving and relapse in addiction. This monopolization of attentional resources bias the addict toward the processing of drug-related cues and reduces the likelihood of evaluating alternative behaviors and coping strategies. A more thorough understanding of the neurobiological mechanisms underlying these cognitive changes will aid in the development of more efficacious ways to treat this major public health problem. The proposed experiments utilize an innovative enzyme-selective microelectrode array to reveal the effects of psychostimulants (nicotine and amphetamine) on cortical neurochemistry. The studies are designed to validate the rapid, in situ detection of extracellular ACh using these microelectrodes as a sensitive measure of cholinergic transmission. ACh-derived signals will be determined at a temporal (i.e. second-by-second) and spatial (i.e. 10-20 mu m) resolution that far exceeds conventional techniques. We will first test this electrochemical method in anaesthetized rats (in order to optimize several electrochemical, neurobiological, and procedural variables). After optimizing the parameters of electrochemical recording, we will then validate the method in awake rats following the administration of psychostimulants and environmental stimuli - stimuli that have been shown to increase cortical ACh release following more conventional methods. But, this is only a starting point for a series of important experiments on the neurochemistry of attentional mechanisms in conditions of drug abuse. For the first time, we will be able to study cholinergic transmission within a time-frame that is consistent with the cognitive processes that have been linked to cortical cholinergic transmission and believed to underlie compulsive drug use. In much the same fashion that enhanced voltammetric techniques, and the focus on phasic DA release, have revealed new perspectives on the contributions of accumbens DA to drug-seeking behaviors the ACh- and choline-sensitive microelectrode arrays will allow us to measure cholinergic transmission in subsecond time periods and within discrete regions in order to address important issues in addiction.