Potential cognitive actions of (N-propargly-(3R)aminoindan-5-yl)-ethyl, methyl carbamate (TV3326), a novel neuroprotective agent, as assessed in old rhesus monkeys in their performance of versions of a delayed matching task

(N-propargyl-(3R)-aminoindan-5-yl)-ethyl, methyl carbamate (TV3326), a known neuroprotective agent exhibiting the properties of both an inhibitor of monoamine oxidase (brain selective) and an inhibitor of acetylcholinesterase was administered to seven old rhesus monkeys well trained to perform versions of a delayed matching-to-sample (DMTS) task. An increasing dose regimen of TV3326 was administered orally according to a schedule that allowed the animals to perform the standard DMTS task and a self-titrating version of the DMTS task each week during the study. A distractor version of the task was administered during two of the doses of TV3326. Under the conditions of this experiment TV3326 failed to significantly affect accuracy on the standard DMTS task; however, the drug was very effective in improving the ability of subjects to titrate to longer-duration delay intervals in the titrating version of the task. The maximal drug-induced extension of the self-titrated delay interval amounted to a 36.7% increase above baseline. This increase in maximum delay duration occurred without a significant change in overall task accuracy. TV3326 also significantly improved task accuracy during distractor (interference) sessions. The compound was effective enough to return group performance efficiency to standard DMTS vehicle levels of accuracy. These results were independent of whether trials were associated with a distractor or non-distractor delay interval, and they were independent of delay interval. The lack of delay selectivity in task improvement by TV3326 may not be consistent with a selective effect on attention. TV3326 was not associated with any obvious side effect or untoward reaction of the animals to the drug. Thus, TV3326 may be expected to offer a significant positive cognitive outcome in addition to its reported neuroprotective action. (C) 2003 IBRO. Published by Elsevier Science Ltd. All rights reserved.