There is no universally accepted mechanism of action for racetams. Racetams generally show negligible affinity for common central nervous system receptors, but modulation of central neurotransmitters, including acetylcholine and glutamate, has been reported. Although aniracetam and nebracetam show affinity for muscarinic receptors, only nefiracetam demonstrates nanomolar interactions. Modification of membrane-located mechanisms of central signal transduction is another hypothesis.
In studies with aged rats, marked improvement has been observed in cognitive tasks in experimental groups given piracetam. Performance was further increased with piracetam combined with cholines. Evidence in studies with rats has indicated that the potency of piracetam is increased when administered with choline.
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