Antiorthostatic position of rats during 93-days' tail suspension induced in the brain strongly pronounced edema of nervous tissue, alteration of structure in horoid plexus, pointing out the decrease in liquor secretion by exocytosis and increase in itraventricular pressure, morphological changes in veins and capillaries, reflecting the development of plethora in veins and tendency to thrombogenesis, and also the appearance of structural signs of prolonged arterial vasoconstriction and narrowing of arterial lumen in surface arteries which be considered as an adaptive process lying the obstacles to excessive blood inflow to brain and dumping the pulse wave during prolonged antiorthostatic state.