MORPHOLOGIC AND PATHOPHYSIOLOGIC SIGNS 305 



tue nervous system are also involved in radiation diseases. 



Klimovskaya (1958) noted increased lability of the preganglionic fiber of 

 the cervical sympathetic nerve after irradiation. 



Nakhil'nitskaya (Lebedinsky's laboratory, 1959) demonstrated that the 

 lability of the postganglionic sympathetic nerve is reduced after irradiation. 

 This enabled Lebedinsky (1959) to suggest that "discoordination" of the 

 different vegetative apparatus may play a considerable part in the genesis 

 of responses to radiation. 



Disturbances or distortions of the vegetative responses from certain 

 reflexogenic zones may constitute one of the major factors in the genesis of 

 responses to radiation. 



Popova noted in 1954 that the reflex reaction of the blood process and 

 respiration in response to stimulation of the gastric and rectal interoceptors 

 of cats was first heightened and then lowered after the animals' heads had 

 been exposed to 1,500 r. In 1954, Yaroshevsky noted a disturbance of the 

 reflex leucocytosis under similar conditions. 



In 1957, Chernichenko, experimenting on rabbits, showed that exposure to 

 600 r leads to a phase variation in the vegetative reflexes of the urinary 

 bladder interoceptors. Komarov established in 1957 that the thresholds of the 

 stimulation required for reflex heightening of the blood pressure were raised 

 as a result of irradiation. 



A number of other authors have noted postirradiation variations in the 

 pressor responses to adrenaline, a distortion of the response to Corazol 

 (Metrazol) and lobeline, and a lowering of sensitivity in the chemoreceptors 

 in response to a rise in the COo level in the blood. 



An observation of great interest was made by Kondrateva in 1957 in 

 connection with the change in the character of the vasomotor and respiratory 

 responses to direct stimulation of the hypothalamus after radiation, from 

 which we may assume that the regulation of a number of physiologic proc- 

 esses is distorted in the course of a radiation disease, precisely because of a 

 disturbance of the reflex irritability of the hypothalamus. 



Another factor closely connected with functional disturbances of the cen- 

 tral vegetative apparatus, and possibly even depending on its function, is the 

 severe variations in the activity of the endocrine organs. In this connection, 

 great interest attaches to the functional disturbances of the adrenal cortex 

 noted by several authors, such as Tonkikh in 1958. 



Preliminary investigations performed in our laboratory, indicate that the 

 cortical layer of the adrenal glands is involved in the response to radiation. 



As the scope of investigation widens in regard to both objects and 

 methods, our knowledge of the influence of radiation on various parts of the 

 nerv^ous system is steadily expanding. Today we have convincing evidence 

 of the influence of ionizing radiation on the activity of the trunk apparatus 

 of the nervous system and the cerebellum. 



