Study of PT1 Peptide Analgesic and Anti-Inflammatory Activity on a Local Inflammation Model in Mice CD-1

PT1 peptide isolated from the venom of spider Geolycosa sp. is a modulator of P2X3 receptors that play a role in the development of inflammation and the transmission of pain impulses. The anti-inflammatory and analgesic efficacy of the PT1 peptide was studied in a model of complete Freund's adjuvant-induced paw inflammation in CD-1 mice. The analgesic activity of PT1 peptide was maximum after intramuscular injection at a dose of 0.01 mg/kg, which surpassed the analgesic effect of diclofenac at a dose of 1 mg/kg. The anti-inflammatory activity was maximum after intramuscular injection at a dose of 0.0001 mg/kg; a decrease in paw thickness was observed as soon as 2 h after the administration of the PT1 peptide against the background of inflammation development. All tested doses of PT1 peptide showed high anti-inflammatory activity 4 and 24 h after administration. PT1 peptide at a dose of 0.01 mg/kg when injected intramuscularly simultaneously produced high anti-inflammatory and analgesic effects compared to other doses of the peptide. Increasing the dose of PT1 peptide led to a gradual decrease in its analgesic and anti-inflammatory activity; increasing the dose of intramuscular injection to 0.1 and 1 mg/kg is inappropriate.