Related Experiment Videos
Anorexia in space and possible etiologies: an overview
Monica S Da Silva1, Pamela M Zimmerman, Michael M Meguid
1Surgical Metabolism and Nutrition Laboratory, Neuroscience Program, Department of Surgery, SUNY Upstate Medial University, Syracuse, New York 13210, USA. dasilvam@upstate.edu
Nutrition (Burbank, Los Angeles County, Calif.)
|October 4, 2002
Summary
Spaceflight causes weight loss and anorexia due to microgravity, altered light cycles, and radiation. Stress hormones and serotonin (5-HT) play key roles in reduced appetite and performance.
Area of Science:
- Space physiology
- Neuroendocrinology
- Gastroenterology
Background:
- Space travelers experience significant weight and body mass loss in microgravity, independent of energy expenditure.
- This weight loss is linked to anorexia, leading to substantial caloric deficits and impacting astronaut performance.
- Environmental stressors in space, including microgravity, altered light-dark cycles, and radiation, are implicated in appetite and gastrointestinal function changes.
Purpose of the Study:
- To investigate the neuroendocrine and physiological mechanisms underlying spaceflight-induced anorexia.
- To elucidate the role of serotonin (5-HT) and corticotropin-releasing factor (CRF) in microgravity-related appetite suppression.
- To explore potential countermeasures for enhancing astronaut well-being and performance.
Main Methods:
- Review of existing data and recent rodent studies in microgravity.
- Utilized the antiorthostatic tail-suspension technique to simulate spaceflight stress responses in rodents.
- Investigated the effects of altered light-dark cycles on food intake and body weight in rodent models.
- Proposed the use of gene knockout mice (5-HT, CRF, and receptors) for pathway analysis.
Main Results:
- Microgravity induces stress hormone release and neuroendocrine changes, modulating hypothalamic activity and appetite-related hormones.
- Astronauts exhibit a dietary shift towards carbohydrates, increasing brain serotonin (5-HT) precursor availability and suppressing appetite.
- The antiorthostatic model demonstrated 5-HT's role in reduced food intake and delayed gastric emptying.
- Altered light-dark cycles negatively impact food intake and body weight in rodent studies.
Conclusions:
- Hypothalamic activity modulation, serotonin (5-HT), and corticotropin-releasing factor (CRF) are critical in microgravity-induced anorexia and circadian rhythm disruption.
- Understanding these pathophysiological mechanisms is crucial for developing effective countermeasures to improve astronaut health and performance.
- Gene knockout mouse models offer a promising avenue for detailed pathway investigation.