The potential antagonism of a single oral dose of RU 41,656 10 mg on the memory and attention disturbances induced by scopolamine 0.6 mg s.c. have been investigated in a 3 period, placebo controlled, double blind, cross over study in 12 healthy, young volunteers. The effects of the compounds were evaluated by objective tests (Buschke selective reminding test, CFF, simple reaction time, tapping, arithmetical calculation) and subjective measurements (visual analogue scale, side effects questionnaire). Measurements were taken before treatment and 2, 4 and 7 h after RU 41,656. Scopolamine caused anterograde amnesia and sedative effects as which were not counteracted by RU 41,656.