Acute Central Nervous System Syndrome 



of Burros* 



Daniel G. Brown, Daniel P. Sasmore, and Larry P. Jones 



University of Tennessee-Atomic Energy Commission 



Agricultural Research Laboratory, 



Oak Ridge, Tennessee 



Introduction 



Nerve tissue is usually listed amonfij the tissues most resistant to ionizing 

 radiation. Experimental data from the animals most commonly used in the 

 laboratory a;i\e considerable support to this contention. Very high doses 

 (1,000 r and above) are required to produce pronounced derangement and 

 lesions of the central nervous system in dogs (Peng et al., 1958), monkeys 

 (Arnold et al, 1954; Vogel et al, 1958; Tonnis, 1959), rabbits (Hicks et al, 

 1956), and mice (Hicks et al, 1958; Gleiser, 1954). However, data (Gan- 

 gloff and Haley, 1960; Lebedinsky, 1956) on functional changes of the 

 brain indicate effects at relatively low dose levels. Consistent changes in the 

 conditioned reflex response in the dog have been reported with doses as low 

 as 20-150 r (Girden, 1935). 



The burro seems to be unique in that pronounced symptoms of central 

 nervous system disturbance appear following exposure to relatively low doses 

 of radiation. The dose rate and type of radiation appear to be important 

 factors in this response. Trum et al (1952) observed deaths with central 

 nervous system symptoms in their early studies with burros exposed to total 

 body gamma radiation with dose levels of 600-900 r delivered at 50 r per 

 hour. This paper is a review and discussion of data from recent experiments 

 in which pronounced central nervous system disurbances and lesions were 

 observed. 



Experimental Procedure 



Adult male and female burros (Equus asinus asinus) , 2 to 7 years old, 

 were used. 



* The work was completed under Contract No. AT-40-1-GEN-242 between the 

 University of Tennessee College of Agriculture and the Atomic Energy Commission. 



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