Racetams are a class of drugs that share a pyrrolidone nucleus. Many, such as piracetam, but not all, are considered nootropics. Some such as oxiracetam and phenylpiracetam are also stimulants. Others such as levetiracetam and seletracetam are anticonvulsants.
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.
Racetams are understood to work by activating glutamate receptors that are colocalized with cholinergic receptors, thus increasing the frequency of activation of the latter. The racetams consequently increase memory capacity by a similar method as acetylcholinesterase inhibitors.
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