[Antagonism of piracetam with proline in relation to mnestic effects].

Based on the authors' previous data showing that the lipophylic cethyl group promotes the penetration of amino acids through the blood-brain barrier, proline cethyl ester was synthesized and studied as a neuropharmacological tool. The substance administered to rats systemically (intraperitoneally) was shown to be able to provoke a deep amnesia when tested by the conditioned avoidance performance. Piracetam abolished the amnestic effect of proline cethyl ester while sodium hydroxybutyrate administered in the dosage range provoking the nootropic effect did not change that amnesia. The data suggest that proline may be considered as one of the possible endogenous amnestic factors. The close structural similarity of the piracetam cyclic fragment to proline, which resulted in their competition, appears to be one of the reasons for piracetam antiamnestic activity.