NICOTINIC MODULATION OF DOPAMINE RELEASE STUDIED WITH A CHANNEL-BASED BIOSENSOR

描述(申请人提供)：调节多巴胺释放是滥用药物可能劫持奖赏回路并导致上瘾的一种方式。例如，尼古丁通过多巴胺能神经元突触前终末上的尼古丁受体直接调节多巴胺的释放。然而，目前监测多巴胺释放及其调制的方法缺乏一个重要的时空敏感性水平，而这种敏感性在谷氨酸和GABA突触等快递质突触中被视为理所当然。快速突触靶细胞上的配基门控通道允许以低于1ms的时间分辨率忠实地检测单量子。用目前应用于多巴胺突触的电化学和光学技术，这种分辨率是不可能达到的，多巴胺突触激活的是G蛋白偶联受体，而不是离子受体。在这里，我们建议将无脊椎动物配体门控的多巴胺通道异源引入啮齿动物多巴胺神经元的突触后靶点。这将使我们能够以通常为快速突触保留的时空分辨率来研究多巴胺释放和尼古丁对多巴胺释放的调制。我们预计，这种新的方法将填补我们对滥用物质行为的理解方面的一个重要空白，并可能导致新的治疗策略。 与公共健康相关：药物滥用和成瘾造成巨大的社会损失。在任何针对这一问题的攻击中，我们都应该包括一些策略，以加强对滥用药物对大脑信号系统造成的最早变化的理解。不幸的是，由于方法学上的限制，我们目前无法窥视滥用药物引起的信号最快、最早的变化。我们建议引入一种新工具，使我们能够以前所未有的分辨率检查尼古丁引起的变化，尼古丁是滥用的典范药物。因此，我们将对尼古丁和其他滥用药物如何劫持正常的大脑电路和信号获得新的见解。

DESCRIPTION (provided by applicant): Modulation of dopamine release is one way that drugs of abuse likely hijack reward circuitry and lead to addiction. For instance, nicotine directly modulates dopamine release through nicotinic receptors on presynaptic terminals of dopaminergic neurons. However, current methodologies to monitor dopamine release and its modulation are missing an important level of spatiotemporal sensitivity that is taken for granted at fast transmitter synapses like glutamate and GABA synapses. Ligand-gated channels on target cells at fast synapses allows faithful detection of single quanta with temporal resolution below 1 ms. This level of resolution is not possible with current electrochemical and optical techniques that are applied to dopamine synapses, which activate G protein coupled receptors rather than ionotropic receptors. Here we propose to heterologously introduce an invertebrate ligand-gated dopamine channel into postsynaptic targets of rodent dopamine neurons. This will allow us to study dopamine release and nicotinic modulation of dopamine release with spatiotemporal resolution typically reserved for fast synapses. We anticipate that this new methodology will fill an important gap in our understanding of the actions of abused substances and may lead to new therapeutic strategies. PUBLIC HEALTH RELEVANCE: Drug abuse and addiction take an enormous societal toll. In any attack on the problem, we should include strategies to enhance understanding of the earliest changes wrought by drugs of abuse on brain signaling systems. Unfortunately, we are currently unable to peer into the fastest, earliest changes in signaling induced by abused drugs because of limitations in methodologies. We propose to introduce a new tool that will allow us to examine changes induced by nicotine, an exemplar drug of abuse, with unprecedented resolution. We will thereby gain new insights into how nicotine and other abused drugs hijack normal brain circuitry and signaling.