Anxiolytic activity of endogenous nootropic dipeptide cycloprolylglycine in elevated plus-maze test

Bull Exp Biol Med. 2001 May;131(5):464-6. doi: 10.1023/a:1017928116025.


Testing in an elevated plus-maze revealed dose-dependent anxiolytic activity of piracetam analog cycloprolylglycine. Intraperitoneal injection of this agent (0.05 mg/kg) 9-fold prolonged the time spent in open arms compared to the control, without affecting the total motor activity. This effect was stereo-selective: D-enantiomer in doses of 0.05 and 0.1 mg/kg was inactive. Therefore, cycloprolylglycine is similar to piracetam in not only nootropic, but also anxiolytic activity. The existence of an endogenous system responsible for the co-regulation of memory and anxiety is hypothesized.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Anxiety Agents / pharmacology*
  • Anxiety / drug therapy*
  • Dose-Response Relationship, Drug
  • Glycine / analogs & derivatives*
  • Glycine / pharmacology*
  • Male
  • Maze Learning / drug effects*
  • Memory / drug effects
  • Nootropic Agents / pharmacology*
  • Peptides, Cyclic / pharmacology*
  • Rats
  • Stereoisomerism


  • Anti-Anxiety Agents
  • Nootropic Agents
  • Peptides, Cyclic
  • cyclo(prolylglycyl)
  • Glycine