Noscapine antagonizes vasoconstrictor action of bradykinin in isolated human umbilical artery

It has been demonstrated that noscapine, an antitussive opioid alkaloid, could antagonize bradykinin- induced responses such as bradykinin effects in guinea-pig ileum, cough induced by bradykinin receptor agonist and angiotensin converting enzyme inhibitors, and brain damage after brain edema both in neonatal rat model and in patients with stroke. In the present study, the effect of noscapine on bradykinin-induced constriction of human umbilical artery was investigated. Segments of human umbilical cords were obtained from women with normal full term pregnancies. Concentration-response curves for bradykinin (1-1000 nM) were constructed in the absence and presence of noscapine (1-1000 nM). To show the specificity of noscapine for bradykinin-induced constriction in the tissue, the effect of noscapine (10 pM) on vasoconstriction produced by histamine were also examined. The results showed that noscapine could antagonize the constriction produced by bradykinin in human umbilical artery. It was also demonstrated that noscapine was capable of reducing histamine-induced contractile response. It is concluded that noscapine can antagonize bradykinin-induced constriction of human umbilical artery in a nonspecific manner. Thus, noscapine is likely to find a clinical application in pathologic conditions accompanied by higher vascular sensitivity to bradykinin in pregnancy.