LOW-LEVEL CHRONIC GAMMA IRRADIATION AS A FACTOR IN AUDIOGENIC SEIZURES OF MICE.

The incidence of tetany after audiogenic seizure testing in offsprings of C57B1 x DBA/2 mice that were irradiated with 20 r of gamma -irradiation delivered at the rate of 2 r/day for the first 10 1/2 days of gestation was significantly increased (P < 0.01) in both male and female mice. The female appears to display a greater sensitivity to irradiation, since her death rate was significantly increased (P < 0.01), equaling the death rate of the male, which did not change with irradiation. It thus appears that audiogenic seizure may be of value in serving as a biological indicator of low-level radiation damage. The fact that the reasons for the increased seizure susceptibility after chronic lowlevel gamma -radiation are not understood does not lessen the usefulness of this new tool as the techniques become refined. The application of standardized stimuli, however, will assist in obtaining reproducible results in different laboratories. (auth)