In vitro activity: Zaltoprofen binds to specific sites on the protein of the bradykinin B2 receptor, hence we have examined the effect of zaltoprofen on bradykinin-induced responses of adult DRG neurons to investigate possible interaction sites. Zaltoprofen most potently inhibits bradykinin-enhancement of capsaicin-induced Ca2+ uptake into DRG neurons. Zaltoprofen also significantly inhibits bradykinin-induced 12-lipoxygenase (12-LOX) activity and the slow bradykinin-induced onset of substance P release from DRG neurons. Zaltoprofen produces an analgesic action on bradykinin-induced nociceptive responses by blocking the B(2) receptor-mediated pathway in the primary sensory neurons. Zaltoprofen completely inhibits the bradykinin-induced increase of [Ca(2+)](i), which is inhibited by B(2) antagonist D-Arg-[Hyp(3), Thi(5,8), D-Phe(7)]-bradykinin, but not by B(1) antagonist. Zaltoprofen at 1nmol shows strong analgesic action on BK (i.pl.)-induced nociceptive flexor responses, whereas loxoprofen or its active metabolite loxoprofen-SRS does not. Zaltoprofen also inhibits the nociception induced by [Tyr8]-BK, a specific agonist of B2-type BK receptor, but does not affect the nociception by [Lys-des-Arg9]-BK, a specific agonist of B1-type BK receptor. Zaltoprofen is a non-steroidal anti-inflammatory drug (NSAID) causes potent inhibition of cyclooxygenase-2 with fewer side effects on the gastrointestinal tract.

Neuropharmacology. 2005 Jun;48(7):1035-42; Int J Mol Med. 2002 Apr;9(4):369-72.