Analgesic activity of new ligands of the NMDA receptor complex

Abstract

BACKGROUND: The activation of spinal cord NMDA receptors is a key factor in the pathogenesis of acute and chronic pain. Therefore, the use of existing NMDA antagonists in analgesic schemes and the development of new compounds targeting the NMDA receptor complex are gaining attention. New ligands of the glutamate NMDA receptor complex are derivatives of imidazole-4,5-dicarboxylic acid. The conformational rigidity of the molecules of imidazole-4,5-dicarboxylic acid derivatives allows for increased selectivity of interaction and reduced side effects. AIM: This study aimed to investigate the analgesic effect of new ligands of the glutamate NMDA receptor complex, which are derivatives of imidazole-4,5-dicarboxylic acid, in rats using the tail-flick test and the formalin test. MATERIALS AND METHODS: The analgesic activity of the compounds was examined in a model of acute somatic (thermal) pain in the tail-flick test and model of somatic pain induced by algogens in the formalin test. The tested compounds (IEM-303 and IEM-2044) were administered intraperitoneally at doses of 5, 10, 15, and 20 mg/kg. Мetamizole was used as the comparison drug. RESULTS: The experiments demonstrated a significant dose-dependent analgesic effect of the tested compounds on the experimental models of acute pain at doses of 5–20 mg/kg. The tail-flick latency increased by 1.4–1.7 times in the IEM-2044 and IEM-303 groups compared with the value in the control group. CONCLUSIONS: The analgesic activity of the tested compounds at 10–20 mg/kg doses was comparable to that of metamizole, indicating the prospect of developing these agents and further searching for effective and safe analgesics in this pharmacological class.