Racetams are understood to work by allosterically modulating glutamate receptors, specifically AMPA receptors, leading to Ca2+ influx that is excitatory.[8] Racetams are posited to enhance memory through interaction with glutamate receptors in the central nervous system.
In studies with aged rats, marked improvement has been observed in cognitive tasks in experimental groups given piracetam. Performance was further increased when piracetam was combined with choline. Evidence in studies with rats has indicated that the potency of piracetam is increased when administered with choline.[16]
Some agents included in the racetam family are not technically racetams themselves in terms of chemical structure and instead are closely related compounds.[17] They may be referred to as "racetam-like".[17][2] These agents include aloracetam, molracetam, omberacetam (noopept), padsevonil, and tenilsetam.[17][6][18]
Society and culture
Legality
Australia
All racetams are schedule 4 substances in Australia under the Poisons Standard (February 2020).[19] A schedule 4 substance is classified as "Prescription Only Medicine, or Prescription Animal Remedy – Substances, the use or supply of which should be by or on the order of persons permitted by State or Territory legislation to prescribe and should be available from a pharmacist on prescription."[19]
^ abcdMalykh AG, Sadaie MR (February 2010). "Piracetam and piracetam-like drugs: from basic science to novel clinical applications to CNS disorders". Drugs. 70 (3): 287–312. doi:10.2165/11319230-000000000-00000. PMID20166767.
^ abcGualtieri F, Manetti D, Romanelli MN, Ghelardini C (2002). "Design and study of piracetam-like nootropics, controversial members of the problematic class of cognition-enhancing drugs". Current Pharmaceutical Design. 8 (2): 125–138. doi:10.2174/1381612023396582. PMID11812254.
^ abGouliaev AH, Senning A (May 1994). "Piracetam and other structurally related nootropics". Brain Res Brain Res Rev. 19 (2): 180–222. doi:10.1016/0165-0173(94)90011-6. PMID8061686.
^Copani A, Genazzani AA, Aleppo G, Casabona G, Canonico PL, Scapagnini U, Nicoletti F (April 1992). "Nootropic drugs positively modulate alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-sensitive glutamate receptors in neuronal cultures". Journal of Neurochemistry. 58 (4): 1199–204. doi:10.1111/j.1471-4159.1992.tb11329.x. PMID1372342.
^Molina-Carballo A, Checa-Ros A, Muñoz-Hoyos A (July 2016). "Treatments and compositions for attention deficit hyperactivity disorder: a patent review". Expert Opin Ther Pat. 26 (7): 799–814. doi:10.1080/13543776.2016.1182989. PMID27138211. The racetams have different activities [e.g., phenylpiracetam is a stimulant developed and marketed in Russia, piracetam is a nootropic, and levetiracetam is widely used as an anticonvulsant (Figure 17)].
^ abcVeinberg G, Vavers E, Orlova N, Kuznecovs J, Domracheva I, Vorona M, Zvejniece L, Dambrova M (2015). "Stereochemistry of phenylpiracetam and its methyl derivative: improvement of the pharmacological profile". Chemistry of Heterocyclic Compounds. 51 (7): 601–606. doi:10.1007/s10593-015-1747-9. ISSN0009-3122. Phenylpiracetam was originally designed as a nootropic drug for the sustenance and improvement of the physical condition and cognition abilities of Soviet space crews.2 Later, especially during the last decade, phenylpiracetam was introduced into general clinical practice in Russia and in some Eastern European countries. The possible target receptors and mechanisms for the acute activity of this drug remained unclear, until very recently it was found that (R)-phenylpiracetam (5) (MRZ-9547) is a selective dopamine transporter inhibitor that moderately stimulates striatal dopamine release.19
^Sommer S, Danysz W, Russ H, Valastro B, Flik G, Hauber W (December 2014). "The dopamine reuptake inhibitor MRZ-9547 increases progressive ratio responding in rats". The International Journal of Neuropsychopharmacology. 17 (12): 2045–2056. doi:10.1017/S1461145714000996. PMID24964269. Here, we tested the effects of MRZ-9547 [...], and its l-enantiomer MRZ-9546 on effort-related decision making in rats. The racemic form of these compounds referred to as phenotropil has been shown to stimulate motor activity in rats (Zvejniece et al., 2011) and enhance physical capacity and cognition in humans (Malykh and Sadaie, 2010). [...] MRZ-9547 turned out to be a DAT inhibitor as shown by displacement of binding of [125I] RTI-55 (IC50 = 4.82 ± 0.05 μM, n=3) to human recombinant DAT expressed in CHO-K1 cells and inhibition of DA uptake (IC50 = 14.5 ± 1.6 μM, n=2) in functional assays in the same cells. It inhibited norepinephrine transporter (NET) with an IC50 of 182 μM (one experiment in duplicate). The potencies for the l-enantiomer MRZ-9546 were as follows: DAT binding (Ki = 34.8 ± 14.8 μM, n=3), DAT function (IC50 = 65.5 ± 8.3 μM, n=2) and NET function (IC50 = 667 μM, one experiment performed in duplicate).
^Stutz PV, Golani LK, Witkin JM (February 2019). "Animal models of fatigue in major depressive disorder". Physiology & Behavior. 199: 300–305. doi:10.1016/j.physbeh.2018.11.042. PMID30513290. In a study performed by Sommer et al. (2014), healthy rats treated with the selective dopamine transport (DAT) inhibitor MRZ-9547 (Fig. 1) chose high effort, high reward more often than their untreated matched controls. Unlike similar studies, however, depressive symptoms were not induced before treatment; rather, baseline healthy controls were compared to healthy rats treated with MRZ-9547. [...] In one study, the selective DAT inhibitor MRZ-9547 increased the number of lever presses more than untreated controls (Sommer et al., 2014). The investigators concluded that such effort-based "decision making in rodents could provide an animal model for motivational dysfunctions related to effort expenditure such as fatigue, e.g. in Parkinson's disease or major depression." Based upon the findings with MRZ-9547, they suggested that this drug mechanism might be a valuable therapeutic entity for fatigue in neurological and neuropsychiatric disorders. [...] A high effort bias been reported with bupropion (Randall et al., 2015), lisdexamfetamine (Yohn etal., 2016e), and the DA uptake blockers MRZ-9547 (Sommer et al., 2014), PRX-14040 (Fig. 1) (Yohn et al., 2016d) and GBR12909 (Fig. 1) (Yohn et al., 2016c).
^Bartus RT, Dean RL, Sherman KA, Friedman E, Beer B (1981). "Profound effects of combining choline and piracetam on memory enhancement and cholinergic function in aged rats". Neurobiology of Aging. 2 (2): 105–11. doi:10.1016/0197-4580(81)90007-5. PMID7301036.
^ abc"Classification Status of Racetams"(PDF). Medsafe. 2015. Retrieved 1 October 2024. Many of the products are based on a group of compounds known collectively as racetams or 'racetam-like' substances. [...] In addition, three substances that do not strictly meet the racetam definition (due to lack of a 2-pyrrolidone ring) are typically described as being part of the racetam family. These are aloracetam, molracetam and noopept.
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