Kallidin applied to the human nasal mucosa produces algesic response not blocked by capsaicin desensitization

Abstract

Various kinins (dissolved in 50 μl) were applied to the nasal mucosa of healthy human volunteers to test the algesic and proinflammatory effects of these peptides in an intact human tissue. [des-Arg 9]-bradykinin (0.5 μmol) was found to be inactive, while bradykinin (0.05–0.5 μmol) and especially kallidin (0.005–0.5 μmol) induced: (a) a mild painful sensation described as burning and pricking (latency 30 s, duration 3–5 min), (b) perception of pulsatility and obstruction in the nasal cavity (onset 1 min, duration 6–8 min). Substance P (0.5 μmol) and neurokinin A (0.5 μmol) produced slight obstruction and weak pulsatile sensation but not pain. Capsaicin (0.05 nmol) produced pain and secretion of fluid, but not pulsatile sensation. The effects of kallidin were not affected by repeated (to induce desensitization) applications of capsaicin (0.5 μmol). Likewise, ipratropium bromide (80 mg in 100 μl) did not affect responses to kallidin. In an intact human tissue, kallidin produces various effects, including an algesic response, that are apparently independent from activation of B 1 receptors and from desensitization of capsaicin-sensitive primary afferents.