ABSTRACT
Intraperitoneal administration of tripeptide Gly-His-Lys to male rats in doses of 0.5, 5, and 50 µg/kg 12 min before the start of the experiment produced an anxiolytic effect in the elevated plus maze test manifested in an increase in the time spent in open arms and shortened time spent in the closed arms. The anxiolytic effect was most pronounced after injection of 0.5 µg/kg peptide and decreased with increasing the dose of the peptide. Replacement of L-lysine with D-lysine in the tripeptide molecule was accompanied by a significant weakening of the neurotropic effects in all studied doses. Attachment of D-alanine to N- or C-terminus of Gly-His-Lys peptide leveled its anxiolytic action in all doses; significant changes in some measures of increased anxiety after administration at 50 µg/kg were found.
Subject(s)
Anti-Anxiety Agents/therapeutic use , Anxiety/drug therapy , Oligopeptides/therapeutic use , Animals , Anti-Anxiety Agents/administration & dosage , Male , Maze Learning/drug effects , Oligopeptides/administration & dosage , RatsABSTRACT
The intraperitoneal administration of Gly-His-Lys tripeptide to male BALB/c mice 12 min before the beginning of the study at doses 0.5, 1.5, 5, 15, and 50 mg/kg produced analgesic effect in the hot-plate test, which was manifested by an increase in the duration of the latent period of the paw-licking reaction. The replacement of L-lysine by D-lysine in the tripeptide molecule was accompanied by significant weakening of the analgesic effect after administration in the same doses. The attachment of D-alanine to N- or C-end of Gly-His-Lys peptide led to leveling of the analgesic effect. On the contrary, after the administration of these analogs, the duration of the latent period of the paw-licking reaction was increased in almost all experimental groups of animals and reached in some cases significant differences that were indicative of the manifestation of algic effects of the modified peptides.
