Enhancement of performance in the Hebb-Williams maze by magnesium pemoline

Effects of magnesium pemoline in dimethylsulfoxide on reversal learning, motor activity, and water intake

52 rats were given reversal training in a T-maze under magnesium pemoline either dissolved in dimethylsulfoxide (DMSO) or suspended in gum tragacanth. The course of reversal learning was unaltered as a consequence of drug administration except for the deleterious performance of the magnesium pemoline in DMSO animals on the 10th reversal. Regardless of vehicle, magnesium pemoline enhanced motor activity in an L-maze. While both magnesium pemoline groups exhibited reduced water consumption relative to controls, both DMSO groups exhibited an increase, concurrent with reduced body weight. It is suggested that DMSO is not an inert placebo and should be used with caution in repeated-administration behavioral studies.