Effect of GHK, PGP and GHK-PGP peptides on temperature pain sensitivity in rats

Objective. To investigate the effect of GHK, PGP and GHK-PGP peptides on spinal and supraspinal mechanisms of thermal pain sensitivity in rats. Material and methods. The experiments were performed on 100 male Wistar rats weighing 170—190 g. We used peptides synthesized at the National Research Center “Kurchatov Institute”: GHK (Gly-His-Lys), PGP (Pro-Gly-Pro), GHK-PGP (Gly-His-Lys-Pro-Gly-Pro). These peptides were administered intraperitoneally at doses of 0.5, 5.0 and 50.0 μg/kg once 15 min before the experiment. Control animals received equivalent volumes of saline solution. Pain sensitivity was studied using hot-plate and tail-flick tests. Results. GHK peptide has analgesic effect for pain caused by thermal irritation in hot-plate test at doses of 0.5 and 50.0 μg/kg. PGP peptide showed analgesic effect in minimum dose. GHK-PGP peptide has clear analgesic effect at all doses in hot-plate test and at a dose of 0/5 μg/kg in tail-flick test. Conclusion. GHK and PGP peptides have analgesic effect. Addition of PGP to C-terminus of GHK amino acid sequence potentiates analgesic effect that is manifested at all doses. GHK-PGP peptide demonstrates analgesic action in tail-flick test that indicates activation of segmental mechanisms of pain sensitivity.