Radiosensitivity of the Ageing Brain

Abstract

VARIOUS effects of X-radiation on the function of the central nervous system have been investigated in both new-born and adult animals¹. One of the factors which influences the severity of the X-radiation effects on the central nervous system is the age of the animal¹. New-born rats X-radiated with a single whole-body dose of 500 r. exhibited a mature tonic–clonic seizure pattern elicited by electroshock stimulation of the brain at an earlier age (13 days) than the controls (21 days). It was concluded that X-radiation accelerates maturation of the brain¹. The increased excitability of the developing nervous system after radiation was further demonstrated by increased intensity of spinal cord convulsions elicited by direct stimulation of the cord². In adult rats investigations have demonstrated that exposure to a single dose of whole-body X-radiation as low as 15 r. increases brain excitability assessed by responses to electroshock stimulation¹. The methods of electroshock stimulation of brain and direct stimulation of the spinal cord are used routinely by this and other laboratories to test the level of activity in the central nervous system^8,4.