The space environment provides is an extreme living and working conditions to which humans are not naturally suited and which demands complex process of physiological and psychological adaptation. Space travel has many deleterious side effects on the flight crew due to the '0' g environment. Changes in gravity have detrimental effects on cardiovascular, respiratory and gastrointestinal functions. The vulnerability of the brain to microgravity stress has been of concern as it relates to the fluidic nature of the gray and white matter. Space missions affect the neurophysiological functions of the astronauts which include perpetual, cognitive and psychomotor changes, orthostatic intolerance and vestibular-related changes. Hence, studies carried out under altered gravitational environment might represent a useful tool to investigate the neurobiological and behavioral responses to stressors and may provide insights into the mechanisms underlying development and plasticity of the nervous system. At the molecular level, the extreme conditions of space flight induce lasting changes in growth, cellular structure, and cell-to-cell interactions including down regulation of genes regulating cell proliferation, growth factor cascades, cell cycle, and signal transduction proteins. Induction of oxidative stress by microgravity has been detected both in simulated microgravity as well as in space. Oxidative stress is considered as one of the major factors that can modulate cellular signaling.

doi : 10.5214/ans.0972.7531.2009.160305

Competing interests: None.     Source of Funding: None

Received Date: 01 June 2009     Revised Date: 27 June 2009     Accepted Date: 08 July 2009