The inhibitory effects of local anaesthetics on the vascular flare responses to bradykinin and substance P in human skin.

ABSTRACT

Bradykinin and substance P are involved in inflammation and act through Gq-protein-coupled receptors. Local anaesthetics inhibit the signalling of these receptors and have potent anti-inflammatory actions. The aim of this study was to investigate the effects of local anaesthetics on the cutaneous flare responses to bradykinin and substance P. Skin blood flow responses to intradermal injections of bradykinin and substance P were assessed in the absence and presence of anaesthetic and analgesic concentrations of lidocaine, levobupivacaine and ropivacaine. All local anaesthetics significantly attenuated the vascular responses to bradykinin (p = 0.001) and substance P (p < 0.001). There were no differences in this effect between the different agents, but anaesthetic concentrations had a greater attenuating effect than analgesic concentrations on the substance P response (p < 0.001). Local anaesthetics may therefore be useful in the suppression of inflammation and the prevention of postoperative hyperalgesia.