[The early decrease in the endothelial cells of the cerebral vessels of rats after local irradiation].

Possible causes of diminution of endothelial cells of rat brain vessels immediately after local irradiation have been investigated. It has been shown that the diminution occurs during the first 24 h following irradiation, its value (-15%) being independent of radiation dose within a wide range (from 5 to 100 Gy), and the cellularity is not restored during the subsequent two weeks of observation. Interphase death of part of cells distinguished by high radiosensitivity seems to be the most probable reason for the population heterogeneity observed.