Effects of amphetamine and beta-endorphin fragments on maze performance in rats.

Fragments of beta-endorphin and amphetamine cause similar effects in some tests of maze behavior in rats. The present study served to compare the influence of amphetamine and two beta-endorphin fragments [beta-endorphin (beta E)-(2-9) and beta E-(2-16)] on maze behavior in more detail. In Experiment I no significant effects of amphetamine and the peptides on behavioral performance in three selected Davenport configurations were found. In Experiment II amphetamine increased the frequency of errors and of returns to the start box, but only in the first trial. This effect was dependent on the rats' experience and on the maze configuration. In the next 11 trials, amphetamine slightly decreased the overall frequency of errors and of returns to the start box. Therefore, the effects of amphetamine on maze behavior depend upon the extent of training experience and on the structure of the test mazes. The peptides did not significantly affect maze performance. It is concluded that the effects of amphetamine and the beta-endorphin fragments on maze behavior are not comparable in this maze test.