AMINEPTINE IMPROVES THE PERFORMANCE OF DOGS IN A COMPLEX TEMPORAL REGULATION SCHEDULE

Amineptine is a tricyclic antidepressant with activating properties, t hat stimulates spontaneous locomotor activity in rodents and elevates mood in humans. It mainly inhibits dopamine uptake and weakly increase s dopamine release. Formulating the hypothesis that this drug would de crease waiting capacity, we decided to test amineptine in a Differenti al Reinforcement of Response Duration schedule (DRRD 9 s Limited Hold 1.5 s) in the dog. The drug was administered orally at 2.5, 5.0, 7.5, 10 and 20 mg/kg, 1 h before the experimental session. Between 2.5 and 10 mg/kg, amineptine improved the performance by increasing the respon se (nonsignificantly) and reinforcement (significantly) rates and by i ncreasing the peak of correct responses (significantly). The inverse e ffect was measured for the reinforcement rate (nonsignificantly) and f or the peak of correct responses (significantly) at the dose of 20 mg/ kg. These results were compared to those obtained with other classes o f drugs, like neuroleptics, barbiturates or anxiolytics, that disturbe d the performance, and particularly with low doses of neuroleptics, wh ich also increase the dopamine release. The positive effects of aminep tine on performance (2.5-10 mg/kg) were related to its inhibitory effe ct on dopamine uptake and discussed in terms of improved vigilance and attention, increase of waiting capacity, improved anticipation, and c ognitive enhancement.