Changes of aortae and pulmonary arteries under simulated microgravity and effects of NOS inhibitor on cardiovascular deconditioning

The present study was to determine the effects of simulated microgravity (SM) on the pulmonary artery (PA)and aorta(TA), and to disclose the changes in pathophysiology of cardiovascular deconditioning(CVD) induced by SM and to explore the effects of NOS inhibitor (N-nitro-L-arginine methylester, L-NAME) on CVD. The high hemodynamics in pulmonary and systemic circulation of human bodies appeared during the initial period and super-regulatory phenomena under 6deghead-down tilt bed rest. -30deg tail-suspension resulted in the functional changes, structural remodeling and the changes of ecNOS mRNA and iNOS mRNA in PA and TA endothelial cells from rats. 10^-5 M L-NAME reversed the decrease of contractile response in PA and partly did in TA. The CVD in tail-suspension rats was relative to an increase of NO production from endothelial cells. 10^-6 M L-NAME had an alleviating effect on CVD in tail-suspension rats. NOS inhibitor may have a good foreground in alleviating orthostatic intolerance