Effect of frusemide on bradykinin- and capsaicin-induced contraction of the guinea-pig trachea.
Frusemide, a loop diuretic, inhibits the bronchial response to various bronchoconstrictor stimuli in asthmatic subjects. The underlying mechanisms remain unclear. In order to determine whether frusemide inhibits pharmacologically induced C-fibre stimulation, we investigated the effect of frusemide on bradykinin-, capsaicin-, neurokinin A-, and substance P-induced contraction of the guinea-pig isolated trachea. Frusemide 10(-5) and 10(-4) M produced a significant inhibition of concentration-response curves to bradykinin, which was markedly reduced by indomethacin 10(-6) M. Frusemide significantly reduced capsaicin-induced contraction only in the presence of indomethacin 10(-6) M. Neurokinin A- and substance P-induced contractions were not affected by frusemide and/or indomethacin. Our data suggest that a cyclo-oxygenase pathway is involved in the inhibition by frusemide of the bradykinin-induced contraction, but not in the inhibition of the capsaicin-induced contraction.
Molimard
M
M
Laboratoire de Pharmacologie, Institut Biomédical des Cordeliers, Paris, France.
Advenier
C
C
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D016084:Bronchoconstriction / Q000187:drug effects* / Q000502:physiology; D002211:Capsaicin / Q000494:pharmacology; D005665:Furosemide / Q000494:pharmacology*; D006168:Guinea Pigs; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D015288:Neurokinin A / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
D013373:Substance P; D005665:Furosemide; D015288:Neurokinin A; D002211:Capsaicin; D001920:Bradykinin; D007213:Indomethacin