It is well known that iontophoresis of norepinephrine in capsaicin treated skin is followed by an increase in thermal hyperalgesia. It is unclear if this action on nocicepitive afferents involves the release of prostaglandins. The aim of the present study was to determine: (1) the effect of norepinephrine iontophoresis on spontaneous and evoked pain in the human skin after topical application of capsaicin; (2) the effect of cyclooxygenase (COX) inhibition on changes in pain perception induced by norepinephrine application.
