c-Fos Immunoreactivity of Neurons Associated with Behavioral Stress and the Cardiac Afferent Sympathetic Reflex in Rats
Abstract
Behavioral stress is the chronic psychological and physiological response to stressors, with links to chronic stress disorders such as Post-Traumatic Stress Disorder (PTSD). The amygdala and paraventricular nucleus (PVN) are two brain areas that regulate stress response and modulate the sympathetic nervous system (SNS), causing physiological changes during the “fight-or-flight” response. Additionally, stress is associated with cardiovascular disease, likely due to sustained sympathetic activation. The Cardiac Sympathetic Afferent Reflex (CSAR) relays signals from myocardial receptors to the brain during events such as ischemia to regulate cardiovascular function. CSAR augmentation worsens post-ischemic outcomes by increasing sympathetic activity that exacerbate injury. CSAR sensory input activates neurons in the rostral ventrolateral medulla (RVLM), which project to sympathetic preganglionic neurons in the intermediolateral horn (IML) of the thoracic spinal cord. Both the amygdala and the PVN neurons project to the RVLM. We hypothesize that behavioral stress and the CSAR pathways share overlapping neurocircuitry; therefore, behavioral stress could worsen ischemic outcomes. The project goal is to determine whether RVLM, PVN, and amygdala neurons in the CSAR pathway are also activated by behavioral stress. We will use an animal model of stress where Sprague Dawley rats undergo foot-shock stress twice daily for two hours over five consecutive days. Control rats will not be exposed to stress. Injected fluorophores will retrogradely label neurons linking the RVLM, amygdala, PVN, and spinal cord. Immunohistochemistry will be used to identify c-Fos immunoreactivity in the RVLM, amygdala and PVN, with c-Fos serving as a marker of neuronal activation. This project will determine whether RVLM, amygdala, and PVN neurons activated by behavioral stress are the same neurons retrogradely labeled from the spinal IML and RVLM as part of the CSAR pathway. This project is crucial to understanding the relationship between stress, the brain, and cardiovascular health, particularly with regards to stress disorders.
Start Time
15-4-2026 9:00 AM
End Time
15-4-2026 10:00 AM
Room Number
272
Presentation Type
Oral Presentation
Presentation Subtype
Research-in-Progress
Presentation Category
Health
Faculty Mentor
Chandley Michelle
c-Fos Immunoreactivity of Neurons Associated with Behavioral Stress and the Cardiac Afferent Sympathetic Reflex in Rats
272
Behavioral stress is the chronic psychological and physiological response to stressors, with links to chronic stress disorders such as Post-Traumatic Stress Disorder (PTSD). The amygdala and paraventricular nucleus (PVN) are two brain areas that regulate stress response and modulate the sympathetic nervous system (SNS), causing physiological changes during the “fight-or-flight” response. Additionally, stress is associated with cardiovascular disease, likely due to sustained sympathetic activation. The Cardiac Sympathetic Afferent Reflex (CSAR) relays signals from myocardial receptors to the brain during events such as ischemia to regulate cardiovascular function. CSAR augmentation worsens post-ischemic outcomes by increasing sympathetic activity that exacerbate injury. CSAR sensory input activates neurons in the rostral ventrolateral medulla (RVLM), which project to sympathetic preganglionic neurons in the intermediolateral horn (IML) of the thoracic spinal cord. Both the amygdala and the PVN neurons project to the RVLM. We hypothesize that behavioral stress and the CSAR pathways share overlapping neurocircuitry; therefore, behavioral stress could worsen ischemic outcomes. The project goal is to determine whether RVLM, PVN, and amygdala neurons in the CSAR pathway are also activated by behavioral stress. We will use an animal model of stress where Sprague Dawley rats undergo foot-shock stress twice daily for two hours over five consecutive days. Control rats will not be exposed to stress. Injected fluorophores will retrogradely label neurons linking the RVLM, amygdala, PVN, and spinal cord. Immunohistochemistry will be used to identify c-Fos immunoreactivity in the RVLM, amygdala and PVN, with c-Fos serving as a marker of neuronal activation. This project will determine whether RVLM, amygdala, and PVN neurons activated by behavioral stress are the same neurons retrogradely labeled from the spinal IML and RVLM as part of the CSAR pathway. This project is crucial to understanding the relationship between stress, the brain, and cardiovascular health, particularly with regards to stress disorders.
