[Structural changes in spinal cord gray matter induced by gravitational overloads].

After acute exposure of rats to gravitational overloads (GO) the reactive changes in neurons and interneuronal synapses of spinal cord were found. These are interpreted as morphologic signs of increased functional activity of neurons and activation of interneuronal impulse transmission. Chronic application of GO results in both reactive changes and damage of spinal cord structures. These changes were not seen after an acute exposure to GO, and thus they are associated with the repeated GO, indicating GO cumulative effect. Administration of "Vitavis" provides a membrane-protective effect, especially in respect to mitochondria of neurons and perineuronal glial cells in cervical and thoracic segments of spinal cord. The effect was less pronounced in spinal cord lumbar segments as a result of pericapillary edema, preventing the transport or drug from capillary bed to the neural structures.