title: [Study of the relationship between analgesic activity and structure of synthetic melanocortin analogs].
abstract: Melanocortins, peptides of the family of adrenocorticotropic (ACTH) and melanocyte-stimulating (MSH) hormones, have a wide range of physiological activity. Heptapeptide semax (MEHFPGP) is an analog of the ACTH4-10 fragment. Previously, pronounced nootropic and neuroprotective activities were shown for this peptide; in addition, it decreases pain sensitivity in animals. In this work, the relationship between analgesic activity of the peptide and its structure was studied. The following analogs of the N-terminal ACTH fragments were used: rMEHFPGP, where r is glucuronic acid, KEHFPGP, GEHFPGP, EHFPGP, HFPGP, and ERP. The peptides were administered intraperitoneally at doses of 0.015, 0.05 and 0.5 mg/kg. Rat pain sensitivity was assessed using the paw-withdrawal test. Truncations of the N-terminal residues eliminated the analgesic activity. The peptide analgesic effect was observed after the replacement of the N-terminal methionine with lysine or after the attachment of glucuronic acid to the methionine, while the peptide with glycine instead of the methionine had no effect on pain sensitivity. Hence, the amino acid at position 1 of semax analogs plays a key role in mediating the analgesic effects of the peptides.
authors.forename: D M
authors.initials: DM
authors.lastname: Ivanova
authors.forename: D A
authors.initials: DA
authors.lastname: Vilenskiĭ
authors.forename: N G
authors.initials: NG
authors.lastname: Levitskaia
authors.forename: L A
authors.initials: LA
authors.lastname: Andreeva
authors.forename: L Iu
authors.initials: LIu
authors.lastname: Alfeeva
authors.forename: A A
authors.initials: AA
authors.lastname: Kamenskiĭ
authors.forename: N F
authors.initials: NF
authors.lastname: Miasoedov
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000700:Analgesics / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D007263:Infusions, Parenteral; D008297:Male; D010147:Pain Measurement; D010446:Peptide Fragments / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013329:Structure-Activity Relationship
chemical_list: D000700:Analgesics; D010446:Peptide Fragments; D010455:Peptides; C048487:ACTH (4-7), Pro-Gly-Pro-; D000324:Adrenocorticotropic Hormone