Amygdalar Modulation of Fear-Conditioned Changes in REM Sleep

描述(由申请人提供)：本项目的总体目标是了解杏仁核对感觉输入的处理如何调节基本的睡眠-觉醒机制。我们建议使用线索恐惧条件反射(Cfc)作为一种实验范式来研究杏仁核(Amy)在决定有机体对环境的反应中的更一般的作用。具体地说，我们将研究恐惧条件作用后大鼠快速眼动睡眠(REM)的变化，以及清醒时相关的行为变化(W)。在目前的方案中，我们重点研究了AMY的外侧核(LA)。作为第一个目标，我们将根据标准的氯氟化碳方案研究一组大鼠。我们将扩大我们对这些动物的神经行为评估，包括睡眠中的REM相活动和超声发声(USV)、新奇检测和W期间的冰冻行为。第二个目标是，我们将在一组完全双侧LA电解损伤的大鼠中研究同样的措施。我们将通过用鹅膏糖酸进行细胞毒性损伤来重复损伤研究，以确定先前损伤观察到的变化是否源于细胞破坏而不是纤维损伤。为了证明LA病变通过在训练期间中断条件刺激(CS)-无条件刺激(US)的联系来特异性地干扰睡眠-觉醒的恐惧条件反射，我们将在另一组大鼠中，在紧接在CFC方案的训练之前使用局部麻醉剂利多卡因造成短暂的双侧LA损伤。有证据表明，5-羟色胺(5-HT)在激活和抑制LA的机制中起重要作用，可能是通过兴奋与LA主细胞突触的GABA能中间神经元。作为第三个目标，我们将探索5-羟色胺在CS-US联合过程中的调节作用，这一过程发生在CFC方案的培训期间，并改变睡眠-觉醒行为。在实验1中，我们将在训练一组大鼠之前立即向双侧LA内注射5-羟色胺。在第二个实验中，我们将注射5-羟色胺和非特异性5-羟色胺能拮抗剂。为了开始描述5-羟色胺作用的细胞机制，我们将在第三个实验中，将5-羟色胺与GABAA拮抗剂一起注射。这一建议与人类精神障碍尤其相关，人类精神障碍是在心理压力经历后出现的，涉及睡眠-觉醒行为和睡眠微结构的显著异常。特别是，我们希望深入了解创伤后应激障碍(PTSD)的睡眠障碍，这通常是目前可用的心理治疗和药物治疗的棘手问题。原发性失眠也可能是压力经历的续集，一些患有创伤后应激障碍的人可能会发生REM干扰性失眠。由于影响5-羟色胺功能的药物已被广泛接受用于治疗创伤后应激障碍，因此研究动物体内5-羟色胺能调节是非常重要的，但对其在相关动物模型中的作用却知之甚少。

DESCRIPTION (provided by applicant): The overall objective of this project is to understand the manner in which amygdalar processing of sensory inputs modulates basic sleep-wake mechanisms. We propose to use cued fear conditioning (CFC) as an experimental paradigm for studying the more general role of the amygdala (AMY) in determining an organism's responsiveness to its environment. Specifically, we shall study changes in REM sleep (REM) after fear conditioning in rats, and related behavioral changes during wakefulness (W). In the current proposal, we focus on the lateral nucleus (LA) of AMY. As a first aim, we shall study a group of rats according to a standard CFC protocol. We shall expand our neurobehavioral assessment of these animals to include REM phasic activity during sleep and ultrasonic vocalizations (USV), novelty detection and freezing behavior during W. As a second aim, we shall study the same measures during sleep and W in a group of rats with complete bilateral electrolytic lesions of LA. We shall repeat the lesion study by making cytotoxic lesions with ibotenic acid in order to determine whether the changes observed with the former lesions originate from cellular destruction and not fiber damage. To demonstrate that LA lesions interfere with the fear conditioning of sleep-wake specifically by interrupting conditioned stimulus (CS)-unconditioned stimulus (US) associations during training, we shall, in another group of rats, make temporary bilateral lesions of LA using a local anesthetic, lidocaine, immediately before training in the CFC protocol. There is evidence that serotonin (5-HT) plays an important role in mechanisms of LA activation and inhibition, possibly by exciting GABAergic interneurons that synapse on LA principal cells. As a third aim we shall explore the modulatory role of 5-HT in the CS-US association process that occurs during training in the CFC protocol and alters sleep-wake behavior. In 1 experiment, we will inject 5-HT into LA bilaterally immediately before training a group of rats. In a second experiment, we shall inject 5-HT together with a nonspecific serotonergic antagonist. In order to begin to delineate the cellular mechanisms of 5-HT's actions, we will, in a third experiment, inject 5-HT together with a GABAA antagonist. This proposal has particular relevance to human mental disorders that arise in the aftermath of a psychologically stressful experience and involve significant abnormalities in sleep-wake behavior and the microarchitecture of sleep. In particular, we expect to gain insight into the sleep disturbance in posttraumatic stress disorder (PTSD), which is often intractable to currently available psychotherapeutic and pharmacological treatments. Primary insomnia also may be a sequel to a stressful experience, and REM interruption insomnia may occur in some individuals with PTSD. It is very important to investigate the serotonergic modulation of CFC in animals because drugs that influence 5-HT function have widespread acceptance for treating PTSD yet little is known about their actions in related animal models.