[Structure of spinal cord capillaries in hypokinesia]

Changes in spatial interrelations of the spinal cord capillaries and motoneurons and capillary ultrastructure were studied under hypokinesia. Spatial interrelations between the capillaries and neurons were not demonstrated to change under hypokinesia. They were estimated by the following parameters: area of neuronal profile field, number of capillaries, their length, distance from the nerve cell body, capillary bed area and index of capillary-neuronal interrelations. Quantitative investigation revealed capillary stenosis: their diameter was one and a half times less under hypokinesia. Morphologically, capillary stenosis was accompanied by the basal membrane thickening and endothelial cytoplasm vacuolization. There was a direct relation between endothelial villi and the places of the endothelial cells contacts, dilatation of the contact interstices and solidifying of their borders. Changes in the capillaries were followed by reactions in the pericapillary structures, such as: fibrillae were formed, mitochondrii accumulated in the perivascular glial projections, the membrane next to capillary astrocyte projections underwent desmosome-like condensation. Mitochondrial accumulations were also observed in the nerve cell projections and in their cytoplasm sites contacting with the blood vessels.