ICAL: Impact of Cannabinoids Across Lifespan: Behavioral Project

项目概要：行为项目 ICAL的核心假设是大麻对内源性大麻素（ECB）系统的非生理激活 青春期的暴露会永久性地改变ECB信号，最终导致 认知和动机行为。在这个项目中，我们提出了一个全面的行为评价， 青少年时期接触四氢大麻酚的啮齿动物使用一组经过良好验证的行为任务和标准化的 与其他项目一致的协议，我们将描述雄性和雌性，大鼠和小鼠的行为， 精心挑选的奖励措施，记忆，认知和情感，以确定持续的范围 THC行为效应，以及海马和中皮质边缘区ECB信号的改变 电路是这种效应的基础。我们有两个目标。目的1：表征由以下原因引起的行为表型： 青少年THC暴露我们将在青春期小鼠中表现出延长THC给药的影响， 和两种性别的大鼠（PND 30 - 43），这是人类青少年每日使用大麻的代表。将动物 在成年期（PND 70+）进行标准化行为测定，在奖励，记忆， 认知和情感。其他小组将比较THC对成年动物的影响，以确定是否 青少年接触影响本质上是发展性的，将研究可能出现的行为影响， 随着动物年龄的增长（PND 300+）。在行为测试之后，大脑将被处理用于与行为相关的c-Fos 免疫反应性，以确定行为相关的神经活动的变化。目标2：确定 诱导和维持青少年THC对行为的影响。我们假设THC，通过刺激 大麻素CB1受体（CB1R）在青春期，改变ECB信号和海马可塑性机制 和中皮质边缘回路，导致目标1中确定的持续行为效应。在目标2.1中，我们将 确定持续性青少年THC效应的CB1R依赖性。在目标2.2中，我们将研究 青少年THC诱导的ECB失调所提供的功能，使用选择性药理学的微量注射， 试剂或通过靶向病毒载体沉默/增强基因表达。在目标2.3中，我们将利用化学遗传学 操作来表征和纠正青少年THC引起的电路活动变化。这些研究将提供 第一次全面检查青少年THC效应的行为和回路水平机制 在啮齿类动物中进行了标准化的、有效的实验。此外，它们将提供一个机械框架， 这解释了NIH的预期ABCD联盟的结果，并将有助于揭示真正的 青少年吸食大麻对神经发育的影响

PROJECT SUMMARY: BEHAVIORAL PROJECT ICAL’s core hypothesis is that non-physiological activation of the endocannabinoid (ECB) system by cannabis exposure during adolescence permanently alters ECB signaling, ultimately causing persistent alterations in cognition and motivated behavior. In this project, we propose a comprehensive behavioral evaluation of rodents exposed in adolescence to THC. Using a well-validated set of behavioral tasks and standardized protocols congruent with other Projects, we will characterize male and female, rat and mouse behavior across carefully selected measures of reward, memory, cognition and emotion to determine the scope of persistent THC behavioral effects, and how alterations in ECB signaling within hippocampal and mesocorticolimbic circuits underlie such effects. We have two Aims. Aim 1: To characterize behavioral phenotypes caused by adolescent THC exposure. We will phenotype the effects of prolonged THC administration in adolescent mice and rats of both sexes (PND 30-43), a proxy for daily cannabis use in human teenagers. The animals will be tested in adulthood (PND 70+) on standardized behavioral assays within the domains of reward, memory, cognition, and emotion. Additional groups will compare THC effects in adult animals to determine whether adolescent exposure effects are developmental in nature, and will examine behavioral effects that may emerge as animals age (PND 300+). Following behavioral testing, brains will be processed for behavior-related c-Fos immunoreactivity to determine changes in behavior-related neural activity. Aim 2: To identify mechanisms of induction and maintenance of adolescent THC effects on behavior. We hypothesize that THC, via stimulation of cannabinoid CB1 receptors (CB1R) in adolescence, changes ECB signaling and plasticity mechanisms within hippocampal and mesocorticolimbic circuits, resulting in the persistent behavioral effects identified in Aim 1. In Aim 2.1 we will determine the CB1R-dependence of persistent adolescent THC effects. In Aim 2.2 we will investigate the behavioral functions served by adolescent THC-induced ECB dysregulation, using microinjections of selective pharmacological agents or silencing/enhancing of gene expression via targeted viral vectors. In Aim 2.3 we will utilize chemogenetic manipulations to characterize and correct adolescent THC-induced circuit activity changes. These studies will provide the first comprehensive examination of the behavioral and circuit-level mechanisms of adolescent THC effects under a standardized, validated protocol in rodents. In addition, they will provide a mechanistic framework in which to interpret the results of NIH’s prospective ABCD consortium, and will help reveal the true neurodevelopmental effects of teen cannabis use.