Biological mechanisms of sleep and appetite through orexin and cannabinoid receptor interactions

背景尽管进行了几十年的研究，但关于睡眠和食欲在大脑中是如何调节和联系的，仍然存在许多问题。下丘脑是一个大脑区域，负责协调神经和内分泌系统之间的这些功能。食欲素和大麻素系统都能调节下丘脑神经元的活动。食欲素通过下丘脑神经元刺激觉醒和食欲，而大麻素类通过下丘脑和非下丘脑机制抑制觉醒和刺激食欲。这项建议的目的是探索重叠的食欲素和大麻素系统之间的分子和行为相互作用。有两种食欲素受体--OX1和OX2--被食欲素-A和-B蛋白激活，以增加觉醒和食欲。大麻素受体CB1R被双胺(AEA)和2-花生四烯基甘油(2-AG)激活，调节觉醒和食欲。与CB1R一样，OX1和OX2在相同的神经元中也存在高水平的表达。由于这些受体的位置重叠，受体的相互作用改变了功能，了解这些系统的相互依赖可能会导致对睡眠和食欲的更好理解。CB1R、OX1和OX2之间的功能和物理相互作用，以及这些相互作用对睡眠和食欲的影响需要探索。我的研究假设是，食欲素和大麻素系统相互对立，通过物理相互作用调节觉醒和合作增加食欲。目标与方法本提案包括3个组成部分：细胞信号、行为和组织分析。细胞信号-我们将利用实验室已建立的分析方法来表征OX1、OX2和CB1R之间的相互作用以及细胞信号中受体依赖的变化。行为-我们将分析以食欲素和大麻系统为靶点的药物治疗的小鼠的睡眠和食欲模式。组织分析-我们将确定OX1、OX2和CB1R在小鼠大脑中的物理相互作用，以及药物治疗后受体相互作用是否发生变化。影响本提案中概述的研究将提供有关两个受体系统之间的串扰的关键信息，这两个受体系统使用以前未应用于该领域的方法来调节睡眠和食欲。研究内源性大麻素系统的生物学对于了解大麻的潜在价值、危害减少考虑和营销政策至关重要。科学界致力于建立调节睡眠和食欲的生物机制，这一点很重要。这项研究将使在多个学科工作的研究人员受益；并成为利益相关者了解大麻的睡眠、食物消费和药物考虑的重要科学政策计划。在这个项目中接受培训的HQP将非常有竞争力，因为他们进行对基础科学和政策至关重要的研究。

Background Despite decades of research, many questions remain about how sleep and appetite are regulated and connected in the brain. The hypothalamus is a brain region that coordinates these functions between the nervous and endocrine systems. The orexin and cannabinoid systems both modulate the activity of neurons in the hypothalamus. Orexins stimulate wakefulness and appetite via hypothalamic neurons, whereas cannabinoids supress wakefulness and stimulate appetite via hypothalamic and non-hypothalamic mechanisms. The purpose of this proposal is to explore the molecular and behavioural interactions between the overlapping orexin and cannabinoid systems. There are two orexin receptors - OX1 and OX2 - that are activated by the proteins orexin-A and -B to increase wakefulness and appetite. The cannabinoid receptor CB1R is activated by anandamide (AEA) and 2-arachidonoylglycerol (2-AG)andregulates wakefulness and appetite. OX1 and OX2 are present at high levels in the same neurons as CB1R. Because the location of these receptors overlap and receptor interactions alter function, understanding the co-dependency of these systems may lead to a better understanding of sleep and appetite. The functional and physical interactions among CB1R, OX1, and OX2, and the effects these interactions have on sleep and appetite require exploration. The hypothesis of my research is that the orexin and cannabinoid systems oppose each other to regulate wakefulness and co-operate to increase appetite through physical interactions. Objectives and Approach This proposal has 3 components: cell signaling, behaviour, and tissue analysis. Cell signaling-We will characterize interactions between OX1, OX2, and CB1R and receptor-dependent changes in cell signaling using assays already established in our laboratory.Behaviour -We will analyze sleep and appetite patterns in mice treated with drugs targeting the orexin and cannabinoid systems. Tissue analysis-We will determine where OX1, OX2, and CB1R physically interact in the mouse brain, and whether changes in receptor interaction occur following drug treatments.  Impact The research outlined in this proposal will provide critical information on the cross-talk between two receptor systems that regulate sleep and appetite using methods not previously applied to this field. Research into the biology of the endocannabinoid system is essential to understand the potential values, harms reduction considerations, and marketing policies of Cannabis. It is important that the scientific community work to establish the biological mechanisms by which sleep and appetite are regulated. This research will benefit researchers working in multiple disciplines; and be an important science-to-policy program to stakeholders understanding sleep, food consumption, and drug considerations for Cannabis. HQP trained in this program will be highly employable as they conduct research critical to basic science and policy.