Interactive function of classical neurotransmitters and neuropeptides

神经元不是孤立地发挥作用，而是作为互联网络的一部分。它们可以通过释放GABA和谷氨酸等神经递质来直接将信息传递给相应的神经元。此外，神经元还释放神经肽以调节神经传递。后一个过程虽然对神经元功能至关重要，但很复杂，也没有很好的定义。神经肽与神经递质在同一神经元中共表达，但它们通过不同的机制释放，并且可以旅行更长的距离到达其目标部位。该建议使用产生黑色素浓集激素（MCH）的神经元来确定神经递质和神经肽之间的相互作用功能。MCH是正常能量稳态、奖励和社会行为所必需的，这些行为对生存至关重要，并且在物种间是保守的。重要的是，MCH神经元形成用于研究神经肽的网络功能的工具模型，因为它们共同释放神经递质谷氨酸，并且仅在大脑的一个区域中发现，因此易于分离用于研究。我们最近发现，MCH神经元发送长距离投射到外侧隔，在那里它们释放谷氨酸并功能性地支配外侧隔中的细胞。在这里，我们将确定1）MCH本身是否也在侧隔中释放; 2）MCH是否调节侧隔中的交感神经传递; 3）鉴于谷氨酸在MCH神经元功能中前所未有的作用，我们将确定MCH和谷氨酸是否具有重叠或独立的行为作用。我们的研究计划将使用变革性光遗传学技术来精确控制神经元活动，我们可以通过电生理记录来捕捉，即使是在很小的大脑区域内。由于神经肽的释放可能需要长时间的高频神经刺激，我们可以提供定时光脉冲来特异性激活MCH神经纤维，以引起MCH释放。为了研究MCH和谷氨酸共表达的功能，我们将建立一种新的转基因小鼠模型，在该模型中，我们仅条件性地破坏MCH神经元的谷氨酸能传递，然后将其与缺乏MCH但具有完整谷氨酸系统的小鼠进行比较。总的来说，这些研究将解开MCH和谷氨酸的作用，并提供一个详细的，可能是奖励或社会行为的神经肽能过程的机械理解。这些发现是重要的，因为它们有助于更深入地了解潜在的信息处理的肽能事件。我们正在组建一个高度积极的学生团队，他们将接受尖端技术的指导性实践培训。我们将共同走在这项技术的最前沿，并开发翻译技能和工具来进行创新研究。

Neurons do not function in isolation, but rather, as part of an interconnected network. They can do so by releasing neurotransmitters like GABA and glutamate to directly transmit information to the apposing neuron. Additionally, neurons also release neuropeptides in order to regulate neurotransmission. This latter process though critical to neuronal function, is complex and not well-defined. Neuropeptides co-express with neurotransmitters in the same neuron but they are released by different mechanisms and can travel longer distances to reach their target sites. This proposal uses neurons that produce melanin-concentrating hormone (MCH) to determine the interactive functions between neurotransmitters and neuropeptides. MCH is necessary for normal energy homeostasis, reward and social behaviors, and these actions are critical for survival and are conserved across species. Importantly, MCH neurons form an instrumental model for studying the network functions of a neuropeptide because they co-release the neurotransmitter glutamate and are found only in one region of the brain thus are easily isolated for investigation. We recently showed that MCH neurons send long range projections to the lateral septum where they release glutamate and functionally innervate cells in the lateral septum. Here we will determine if 1) MCH itself is also released in the lateral septum; 2) if MCH regulates glutamatergic transmission in the lateral septum; and 3) given the unprecedented role for glutamate in the function of MCH neurons, we will determine if MCH and glutamate have overlapping or independent behavioral roles.Our research program will use a transformative optogenetic technique to enable precise control of neuronal activity, which we can capture via electrophysiological recordings, even within small defined brain regions. Since neuropeptide release may require prolonged high frequency nerve stimulations, we can deliver timed light pulses to specifically activate MCH nerve fibers to evoke MCH release. In order to study the functions of co-expressed MCH and glutamate, we will generate a novel transgenic mouse model, in which we conditionally disrupt glutamatergic transmission by MCH neurons only, then compare it to mice lacking MCH but with an intact glutamate system. In aggregate, these studies will disentangle the roles of MCH and glutamate and provide a detailed, mechanistic understanding of the neuropeptidergic processes that may underlie reward or social behaviors. These findings are significant as they contribute towards a deeper understanding of peptidergic events underlying information processing.We are assembling a team of highly-motivated students who will receive directed hands-on training on cutting-edge techniques. Together we will be at the forefront of this technology and develop translational skills and tools to conduct innovative research.