Investigation into the role of cyclooxygenase products in the bradykinin response on isolated human myometrium and umbilical artery.

The aim of this study was to investigate the response to bradykinin (BK) on human myometrium and umbilical artery with respect to cyclo-oxygenase (CO) products. Dose/concentration response curves to BK were performed +/-2.79 microM indomethacin. On human myometrium the response to BK (0.001-50 nmol) was biphasic and consisted of a dose-related increase in myometrial tension which was followed by a period of inhibition of myogenic activity. In tissues from P donors the presence of indomethacin had no significant effect on the excitatory response, but the inhibitory component of the response was reduced. In tissues from NP donors indomethacin significantly enhanced the BK effect at higher doses and the inhibitory component of the response was reduced. On the HUA cumulative addition of BK (1-1000 nM) resulted in dose dependent constriction with desensitisation at the highest dose (EC50 = 38 nM). The presence of indomethacin had no significant effect on BK response on HUA. These findings suggest that CO products contribute significantly to response to BK on the human myometrium but not on HUA and that different CO products are produced by P and NP tissue.