[Response of spinal cord capillaries of white rats to exposure to noise]

Changes in diameters of blood capillaries of the white rat spinal cord, peculiar changes in volume and metabolic surface of capillaries in the cervical part of the spinal cord were studied under the effect of noise (90-100 db, 2 h daily, for 2, 4 and 8 weeks). Restorative period was started in 4 and 16 weeks after the experiment was stopped. A considerable narrowing of the capillary lumen was found in the test animals comparing to the normal state. The investigations performed demonstrated that the quantitative changes in the capillary indices depended on the noise duration and were considered as gradual development of adaptive-compensatory reaction of the vascular system to noise. The changes mentioned, however, were not irreversible, as during the restorative period a gradual widening of the capillary diameters was observed. Nevertheless, the "rest" lasting for 16 weeks was not enough for the capillary bed of the spinal cervical part to restore its normal indices.