Effects of Neonatal Irradiation on Learning 



In Rats* 



BiLLEY LeVINSON 



University of Buffalo, 

 Buffalo, New York 



In the radiation literature, the term "protective agent" has been applied 

 to an agent that fulfills one or more of the following criteria: (a) increases 

 survival rate on exposure to a lethal irradiation dose, (b) increases the 

 median survival time, (c) enables reduction of dose, (d) develops radio- 

 resistant subjects, or (e) permits recovery from radiation damage. The last 

 two criteria imply the prevention of generalized or indirect radiation efTects 

 and stem from reports of drug protection administered immediately (Kiinkel 

 and Schubert, 1959) or up to 3 weeks after radiation (Doull and Dubois, 

 1953; Kiinkel et at., 1957; Patt and Swift, 1948). Several recent investi- 

 gators (Latarjet and Gray, 1954; Meier, 1960; Mole, 1959; Pihl and Eld- 

 jam, 1958; Rugh, 1959) have sharply criticized the blanket application of 

 the term "protective agent", and Doherty et al. (1958) have pointed out that 

 although chemicals can increase survival rate or median survival time, they 

 do not afford equal protection to every system in the animal. 



Although reduction in mortality is an important criterion of the effective- 

 ness of chemoprotection, it is equally important to determine whether the 

 disruptive behavioral effects of radiation can also be decreased. As Rugh 

 has noted (1959) levels of exposure below those producing histologic dam- 

 age may nevertheless elicit changes in behavior. For these reasons, it is 

 particularly important to determine whether the irradiated, but protected, 

 animal is as adaptable to his environment as he was before radiation. In 

 this experiment, the problem is approached by comparing maze behavior of 

 protected and unprotected irradiated animals. 



Inasmuch as the adult nervous system has been considered relatively re- 

 sistant to ionizing radiation (Prosser, 1947), and since its effects on the fetal 



* This research was supported by a National Institutes of Health grant. Dr. J. 



Weinstock, of Smith, Kline & French, and Dr. A. Bruce, of the University of 



Buffalo, were consultants, and H. Birch and J. Meyers assisted in the collection of 

 the data. 



659 



