title: Simulated weightlessness to induce chronic hypoactivity of brain norepinephrine for exercise and stress studies.
abstract: Although research on the relationship between exercise training and physiological stress reactivity is increasing, we know little about the involvement of brain neurochemistry. Moreover, the few studies that have been performed have concentrated on animals with normally functioning neurochemistry exposed to an acute stressor. Biomedical research is drawing an association between hypoactivation of the physiological stress response and certain medical conditions. As such, there is a need for an animal model that manifests a chronic hypoactivity of the stress system. In this report we describe the results from studies on norepinephrine changes with actual and simulated weightlessness in animals and humans. There is consistent evidence with rats that 14 d of simulated weightlessness produces reduced norepinephrine turnover in selected brainstem nuclei and peripheral tissue mediating the physiological stress response. Little is known about other brain regions, particularly the hypothlamus. These preliminary data suggest that simulated weightlessness is one method by which a chronic hypoactivity of norepinephrine biosynthesis or release might be induced to study exercise training as an intervention.
authors.affiliation: School of Allied Health Sciences, Indiana University School of Medicine, Indianapolis 46202-5119, USA. msothman@indycms.iupui.edu
authors.forename: M
authors.initials: M
authors.lastname: Sothmann
authors.forename: G K
authors.initials: GK
authors.lastname: Kastello
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001921:Brain / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D009638:Norepinephrine / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology; D013312:Stress, Physiological / Q000378:metabolism*; D018474:Weightlessness Simulation
chemical_list: D009638:Norepinephrine