Psychological stress reduces endocannabinoid tone: mechanisms and possible treatments

一个使退伍军人衰弱的心理健康问题是创伤后应激障碍 (PTSD)，这是一种焦虑症(PTSD)，随着生活经历而发展- 威胁心理创伤。患有创伤后应激障碍的人循环中的 内源性大麻素(ECB)，包括2-氨基酚。由于2-AG信号的中断会导致情绪 紊乱，记忆受损，疼痛加剧，扭转压力的能力- 2-AG产生/降解的诱导变化为创伤后应激障碍的治疗提供了巨大的潜力。 鉴于2-AG信号在应激反应和关联性恐惧学习中的重要性， 需要了解压力是如何导致2-AG水平持续下降的 创伤应激与相关的2-AG减少之间存在的知识差距 内容。啮齿动物暴露在天然捕食者气味中会造成心理压力，导致 增强的联想恐惧学习，因此已被用来模拟创伤后应激障碍的几个方面。 我们之前已经表明，暴露在狐狸尿液中会产生持久的兴奋性增加。 小鼠小脑中通过肾上腺素能受体激活的突触传递。这 大脑区域是对捕食者气味和巩固恐惧的先天反应所必需的 记忆。我们的试验数据显示，捕食者气味暴露减少了2-AG信号在 小脑和该应激源可使抑制性中间神经元的A-K电流消失。因此 我们的中心假设是捕食者气味应激增强了GABA能神经元的兴奋性 从而减少2-AG信号转导，从而减少药物干预 抑制2-AG降解和降低神经元兴奋性将逆转应激诱导的 2-AG水平下降。在目标1中，我们将确定心理压力是否会减少2- 通过增加2-AG的降解或通过减少2-AG的产生来提高AG音调。目标2将测试 情绪应激通过增加抑制性中间神经元减少2-AG信号的假说 活动。我们将测试FDA批准的几种降低神经元活动的药物是否可以 逆转压力引起的变化。因为这项拟议的研究调查了一种新的机制 在心理应激对2-氨基丁酸代谢的调节下，这可能是新的 创伤后应激障碍的治疗策略和新的治疗靶点。

One debilitating mental health problem among veterans is post-traumatic stress disorder (PTSD), which is an anxiety disorder (PTSD) and develops following the experience of life- threatening psychological trauma. Individuals with PTSD have reduced circulating levels of endocannabinoids (eCB) including 2-AG. Since disruption of 2-AG signaling leads to mood disorders, impaired memory extinction and enhanced pain, the ability to reverse the stress- induced change in 2-AG production/degradation holds great potential for the treatment of PTSD. Given the importance of 2-AG signaling in the stress response and associative fear learning, an understanding of how stress produces a lasting decrease in 2-AG levels is needed to bridge the knowledge gap that exists between traumatic stress and the associated reduction in 2-AG content. Exposure of rodents to natural predator odors causes psychological stress, leading to enhanced associative fear learning and thus has been used to model several aspects of PTSD. We have previously shown that fox urine exposure produced a lasting increase in excitatory synaptic transmission via the activation of adrenergic receptors in the mouse cerebellum. This brain region is required for the innate response to predator odor and for the consolidation of fear memory. Our pilot data show that predator odor exposure reduced 2-AG signaling in the cerebellum and this stressor abolished A-type K currents in inhibitory interneurons. Therefore our central hypothesis is that predator odor stress enhances excitability of GABAergic interneurons and thereby reduces 2-AG signaling, thus pharmacological interventions that inhibit 2-AG degradation and reduce neuronal excitability would reverse the stress-induced decrease in 2-AG levels. In Aim 1, we will determine whether a psychological stress reduces 2- AG tone by increasing 2-AG degradation or by reducing 2-AG production. Aim 2 will test the hypothesis that emotional stress reduces 2-AG signaling by increasing inhibitory interneuron activity. We will test whether several FDA approved drugs that reduce neuronal activity can reverse the stress-induced change. Because the proposed study investigates a new mechanism underlying the regulation of 2-AG metabolism by psychological stress, it could suggest novel treatment strategies for PTSD and new therapeutic targets.