The gliovascular interphase in irradiated brain tissue. Electron microscopic investigations on location of specific phosphatases

Abstract

In the brains of rats exposed to a dose of 800 rads of gammma radiation the location of phosphatases hydrolysing the following phosphate esters: adenosinetriphosphate (ATP), cytidinetriphosphate (CTP), guanosinetriphosphate (GTP) and inosinediphosphate (IDP) was determined in the ultramicroscopic structures. Changes were observed in their location in the gliovascular interphase. Early after the exposure (6 hours) the activity of specific phosphatases decreased in brain capillaries, then (48 hours) the reaction product disappeared from the basal membrane of the capillaries and appeared in the endothelium. Later (72 hours -- 7 days) the intensity of the reaction increased in the processes of the astrocytes adhering to the capillary. These changes took place concomitantly with an increase in the permeability of the blood-brain barrier and suggested that specific phosphatases participate in the barrier mechanisms.