Methylphenylpiracetam
Methylphenylpiracetam is a derivative of piracetam and a positive allosteric modulator of the sigma-1 receptor. It differs from phenylpiracetam by having a methyl group.
E1R is the stereoisomer of methylphenylpiracetam that has been shown to have the greatest effect on the modulation of the sigma-1 receptor.
Enantiomers
The two R-configuration enantiomers, i.e. and, of methylphenylpiracetam are more active positive allosteric modulators of the sigma-1 receptor than the two S-configuration enantiomers, i.e. and.| Enantiomer | σ1R PAM effect % |
| erythro- | 222 ± 37 |
| threo- | 191 ± 23 |
| erythro- | 141 ± 40 |
| threo- | 147 ± 31 |
Effects
E1R enhances cognition and has efficacy against cholinergic dysfunction in mice without affecting locomotor activity. Pretreatment with E1R enhanced the σ1R agonist PRE-084's stimulating effect and facilitated passive avoidance retention. It alleviated scopolamine-induced cognitive impairment. The cognition enhancing activity of E1R is higher than that of -phenylpiracetam.Because E1R had no effect on locomotor activity, it was found to be free of potential motor side effects.