524 DOROTHEA STARBUCK MILLER 



TABLE VI 



Effect of Monosodium Glutamate in Protecting DBA/2 Mice from 

 Audiogenic Seizures under Different Environmental Radiation Levels 



DBA/2 mice and of those injected with glutamate. The bimodal curve is 

 typical of uninjected DBA/2 mice, which show many premature seizures. 

 In the injected group maintained in Room R with low level radiation, there 

 was a reduction in the frequency of early seizures and a 10 sec delay in the 

 second peak. In the injected series maintained at background level, the curve 

 was displaced far to the right, with no premature seizures and the second 

 peak 25 sec later than in controls. 



Both the reduction in frequency of seizures and the longer latency of fatal 

 seizures indicate that protection by glutamic acid is much more effective in 

 the absence of extra radiation in the environment. 



Implication of Radioactive Fallout in Increasing Seizure Frequency 



After the colony was moved to Room G, our data appeared to be stabil- 

 ized, with repeatable results in all groups. However, a puzzling development 

 apj>eared in May, 1957, with a sudden, dramatic new increase in seizure 

 susceptibility for the following 6 months (Table VII). 



We investigated the possibility of a new radiation source, which was not 

 found. Records of local radioactive fallout, supplied 1 year later by the New 

 York Operations Office of the Atomic Energy Commission, showed that the 

 sudden rise in seizure frequency coincided exactly with a sharp increase in 

 fallout level. The first litters which showed unusual sound sensitivity were 

 born on April 8; on April 10, an 80- fold increase in beta and gamma radia- 

 tion was recorded by the AEC. There were similar bursts on April 13 and 

 15, and a higher level persisted for several months. 



