Abstract
Pharmacological properties of phenolic dental medicaments such as eugenol (EUG), guaiacol (GUA) and thymol (THY) on analgesic action, blood flow and substance P (SP) release were studied in comparison with that of capsaicin (CAP), a potent SP depletor, because these phenolic compounds are partly similar to CAP in chemical structure. While EUG, GUA and CAP had long lasting analgesic actions on hotplate and formalin tests after intrathecal and intraplantar (i. pl.) injections in mice, THY had no apparent effect. CAP (i. pl.) elicited a transitory pain which was reduced by spantide, and EUG and GUA produced similar effects. EUG and GUA caused a significant increase of cutaneous blood flow in the rat hindpaw, which spantide antagonized in the same manner as CAP. EUA and GUA significantly increased SP release from dental pulp and spinal cord slices in vitro, but were less potent than CAP. These results suggest that the analgesic effect of these phenolic compounds may be due in part to the ability to release SP.
