Effects of methaqualone on learning: a failure to observe tolerance

The study was designed to assess the effects of Methaqualone (MTQ) on learning, as well as the effects of 15 days of pretask drug exposure on performance. Forty CFE rats were randomly divided into four groups: Group I received daily IP injections of MTQ for 15 days prior to and throughout the duration of the task; Group II served as a control for Group I, receiving injections of the carrier vehicle; Group III received MTO at the start and throughout the duration of the task; Group IV served as the control for Group III. The task consisted of two pretraining days of swimming down a straight, all-white alleyway, followed by 5 trials/day for 4 days on a black-white discrimination task in a water T maze, with the white side being reinforced for all animals. Analyses revealed that MTQ animals made significantly more errors than controls. Pretask drug exposure did not significantly alter Group I performance versus Group III. Furthermore, continued injections for half of the animals in Group I and II for eight days following the last learning day did not improve Group I performance when retested on the same task. Thus MTQ adversely affected learning with prolonged drug exposure failing to reverse such debilitation.