Prenatal chemical protection against radiation-induced learning deficiencies

Cysteamine (beta-mercaptoethylamine) was injected into pregnant rats on the 16th day of gestation. They were then irradiated with 185, 110, 50, or 0 R. Four additional groups received the same radiation treatments but were not given cysteamine prior to irradiation. When the offspring of these animals reached adulthood, they were randomly selected to be tested for learning ability in a Lashley III maze where either escape from water or food reinforcement was the motivating factor. In the water maze, there was an inverse relationship between learning ability and radiation dose level with the highest radiation dose resulting in the poorest maze performance. In the irradiated groups that did not receive cysteamine there was an even greater reduction in learning ability and the dose-dependent relationship was much more evident. Where food was the motivating factor, an inverse relationship was found between radiation dose rate and percent survival on the food-deprivation schedule. This was more marked in the gr...