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

尽管经过了几十年的研究，关于睡眠和食欲是如何在大脑中受到调节和联系的，仍然存在许多问题。下丘脑是大脑的一个区域，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清醒和食欲，而大麻素通过下丘脑和非下丘脑机制抑制清醒和刺激食欲。本提案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，它们被食欲素a和b蛋白激活，以增加清醒和食欲。大麻素受体CB1R被anandamide （AEA）和2-花生四烯醇甘油（2-AG）激活，调节清醒和食欲。OX1和OX2在与CB1R相同的神经元中呈高水平存在。由于这些受体重叠的位置和受体的相互作用改变了功能，了解这些系统的相互依赖性可能会更好地理解睡眠和食欲。CB1R、OX1和OX2之间的功能和生理相互作用，以及这些相互作用对睡眠和食欲的影响有待探索。我的研究假设是，食欲素和大麻素系统相互对抗，以调节清醒，并通过身体相互作用合作增加食欲。目的和方法本建议有三个组成部分：细胞信号，行为和组织分析。细胞信号传导-我们将描述OX1， OX2和CB1R之间的相互作用，以及使用我们实验室已经建立的检测方法在细胞信号传导中受体依赖性的变化。行为-我们将分析老鼠的睡眠和食欲模式，这些老鼠接受了针对食欲素和大麻素系统的药物治疗。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。本提案中概述的研究将使用以前未应用于该领域的方法，为调节睡眠和食欲的两个受体系统之间的串扰提供关键信息。对内源性大麻素系统的生物学研究对于了解大麻的潜在价值、减少危害的考虑和营销政策至关重要。重要的是，科学界要努力建立调节睡眠和食欲的生物学机制。这项研究将使多学科的研究人员受益；并成为一个重要的科学政策项目，让利益相关者了解大麻的睡眠、食物消耗和药物考虑。在该项目中接受培训的HQP将在从事对基础科学和政策至关重要的研究时具有很高的就业率。

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.