Limbic modulation of stress-induced alterations in sleep

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DESCRIPTION (provided by applicant): The long-term goal of our research program is to understand the impact of stressful events on sleep, and, in turn, how alterations in sleep are related to the persisting effects of stress. Stressors and conditioned/learned reminders of stressors can produce significant alterations in behavior and sleep. These alterations may vary with the intensity and controllability of the stressor and whether a successful coping strategy was developed. At the neurobiological level, the alterations may involve CRH in limbic regions implicated in stress and emotion, and in the control of arousal. However, the relationship between stress-induced behaviors and alterations in sleep, and their behavioral and neurobiological bases, are poorly understood. In this project, we intend to determine how variations in stressor intensity and controllability can influence post-stress sleep, and we intend to determine the role of CRH and CRH-related neuropeptides in the amygdala in regulating arousal and stress- induced alterations in sleep. Lastly, we will determine whether amygdalar modulation of stress-induced changes in arousal is associated with alterations in activity in brain regions implicated in stress and in brainstem monoaminergic cell groups that have been linked to the regulation of sleep and stress. To accomplish the objectives of this application we will: 1) determine the role(s) of stressor intensity and controllability in the effects of stress on sleep and behavior, 2) determine the role(s) of CRH1 and CRH2 receptors in the amygdala in regulating arousal and sleep, 3) determine the role(s) of CRH1 and CRH2 receptors in the amygdala in stress-induced alterations in arousal and sleep, and 4) we will identify regions involved in stress and in stress-induced alterations in rapid eye movement sleep, the sleep state that may be most impacted by stress. We will also measure heart and respiratory rate and plasma markers of the stress response. Understanding the neurobiology underlying the changes in sleep induced by controllable and uncontrollable stress should increase our understanding of how stress and stress-related emotion affect sleep and, in turn, the role altered sleep may play in the development of stress-related pathology. Such understanding may provide insight into sleep disorders such as insomnia and into emotional disorders in which sleep is affected. It will be especially relevant for insight into posttraumatic stress disorder (PTSD), which is characterized by disturbed sleep after a psychologically traumatic stressor. PUBLIC HEALTH RELEVANCE The goal or this research is to understand the impact of stressful events on sleep, and, in turn, how alterations in sleep are related to the persisting effects of stress. Stressors and even conditioned reminders of stressors can produce significant alterations in behavior and sleep. It is known that the effects of stressor intensity and controllability are important factors in the long-term effects of stress. However, it is not know how these factors impact sleep, or what role altered sleep may play in the long-term effects of stress. We will determine how stressor intensity and controllability affect post-stress sleep, and we will examine the role of corticotropin releasing hormone in the amygdala, a center of emotion in the brain, in regulating post-stress sleep. The insight provided by these studies may lead to improved treatments for sleep disorders such as insomnia and into emotional disorders in which sleep is affected. It will be especially relevant for understanding and potential treatment of posttraumatic stress disorder (PTSD), which is characterized by disturbed sleep after a psychologically traumatic stressor.