Effect of maternal high histidine levels on activity and maze retention in the rat.

Groups of pregnant rats were maintained on either a histidine-high diet, or received periodic injections of C-nitromethane, or they received both treatments throughout gestation. Later, the offspring were tested in an open field for activity in a maze-learning task and retested for the retention of the maze habit. Results showed that both nitromehane injections and histidine-high diets resulted in impaired performance. On the open field test, the experimental subjects were more active, and on initial learning of the maze pattern they demonstrated a learning deficit. However, when retested 7 and 30 days later, they showed no deficit in retention of the maze habit. In addition, an analysis of covariance indicated that the hyperactivity and learning deficit were independent characteristics of maternal hyperhistidinemia.