Anxiolytic Effect of GHK-PGP Peptide and Its Structural Analogues in a Test with Punished Behavior

The anxiolytic effects of Gly-His-Lys-Pro-Gly-Pro peptide (GHK-PGP) and its proline-containing analogs were studied in a test with punished behavior. Peptides Gly-His-Lys (GHK), Pro-Gly-Pro (PGP), GHK-PGP, Gly-His-Lys-Gly-Pro (GHK-GP), and Gly-His-Lys-Pro (GHK-P) were used. Anxiolytic activity was assessed in the Vogel conflict test. The peptide GHK had no anxiolytic effect, while PGP and GHK-PGP produced an anxiolytic effect in certain doses. Presumably, the anxiolytic effect of the peptide GHK-PGP is determined by the action of PGP in the absence of the blocking effect of GHK. The peptides GHK-P and GHK-GP also had anxiolytic effects, which may indicate the presence of anxiolytic activity in various proline-containing amino acid sequences attached to GHK.