Orofacial antinociceptive effect of a novel 2-amino-thiophene derivative and its possible targets of action.

Orofacial pain impairs quality of life, and current therapies, limited in efficacy and associated with adverse effects, drive the search for new treatments. Thiophene derivatives exhibit remarkable therapeutic properties, including antinociceptive and anti-inflammatory activities, with recent studies demonstrating superior activity compared to commercial drugs, highlighting their relevance in the design of novel agents. This study investigated the antinociceptive effect of the thiophene derivative 2-[(4-diethylamino-benzylidene)-amino]-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carbonitrile (7CN03) and its possible mechanisms of action. In vivo tests were performed on male mice (n = 6 per group), and nociception was induced by formalin, capsaicin, and glutamate 1 h after treatment. Facial rubbing was used as a parameter to measure nociceptive behavior. 7CN03 exhibited significant action during the neurogenic phase of the formalin test at different doses (1 mg/kg, 0.1 mg/kg, and 0.01 mg/kg), reducing nociceptive behavior by up to 56%. During the inflammatory phase, the 1 mg/kg dose exerted an antinociceptive effect, reducing nociceptive behavior by 32% (p < 0.05). In the glutamate test, 7CN03 blocked nociception by up to 90% (p < 0.001), and in the capsaicin test, it reduced nociceptive behavior by up to 74%. Molecular docking studies predicted higher binding affinity of 7CN03 for µ-opioid (-97.00 Kcal/mol), TRPV1 (-87.79 Kcal/mol), and NMDA (-104.86 Kcal/mol) receptors when compared with cocrystallized ligands. The findings suggest that the evaluated thiophene derivative exhibits an orofacial antinociceptive effect, with a mechanism of action likely mediated by opioid, transient receptor potential vanilloid, and glutamatergic receptors.