Selectivity of ruthenium red in inhibiting bronchoconstriction and CGRP release induced by afferent C‐fibre activation in the guinea‐pig lung

Abstract

Ruthenium red (3 × 10 ‐4 M ) aerosol attenuated the cough induced by nebulized citric acid in conscious guinea‐pigs. Citric acid‐induced coughing is mediated via capsaicin‐sensitive neurons. However, cigarette smoke‐induced coughing, which involves capsaicin‐resistant mechanisms, was not affected by ruthenium red. In conclusion, ruthenium red selectively inhibits the capsaicin, resiniferatoxin and citric acid‐induced excitation of the sensory nerves as revealed by calcitonin gene‐related peptide‐like immunoreactivity release, bronchoconstriction and coughing, suggesting that these agents share a common mechanism of action.