[Plastic changes of structure, function and perivascular innvervation of arterial vasculature during simulated...

At present, whether structural remodeling and functional adjustment of arterial vasculature might occur during weightlessness has not yet been fully recognized. Hence, a serial work using tail-suspension rat model aimed at elucidating the nature, time course and reversibility of changes in structure, function and perivascular innervation of arterial vasculature in different body parts during and after simulated weightlessness was started several years ago in this laboratory. Our results have demonstrated the differentiated effects of simulated weightlessness on arterial vasculature in different body parts: (1) in the hindquarter arteries and arterioles, it leads to atrophic remodeling changes, diminished vasoconstrictor responsiveness and perivascular hypoinnervation; (2) in the fore body part, it leads to hypertrophic changes, enhanced responsiveness and hyperinnervation in the arteries. The results suggest that microgravity-induced changes in cardiovascular effector apparatus, e. g., the structural remodeling and functional adjustment in vascular smooth muscle, might play an important role in the genesis of postflight orthostatic intolerance.