Magnesium pemoline: Different effects with different subject stocks

Abstract

in an attempt to determine the effect of long-term administration of MP on performance of tasks of various levels of difficulty and which presumably require various levels of cognitive operation. We conducted one such study with Long-Evans rats and another with Sprague-Dawley rats. We found effects of MP, in both stocks, on performance in a shock-escape situation involving a pole-climbing response. However, there were no consistent effects, in either stock, on performance in other shock-motivated situations. Furthermore, the effects on the pole-climbing performance were different in the two stocks of SS. With the Long-Evans rats, MP inereased the number of responses made during the second day of learning and prolonged extinction, while with the Sprague-Dawley rats, MP decreased the number of responses on the first day of learning and had no effect on extinction. Since these studies had involved running the animals through aseries of shock-motivated tasks before they were trained in the pole-climbing apparatus, there was necessarily a confounding of variables such as length of injection period and interference and transfer relationships among the tasks used. The present study was done in order to determine the effects of MP on the performance of two stocks of Ss without the confounding effects which were present in the previous studies. For this purpose, naive Ss of both stocks were run only on the pole-climbing task.