Figure 2.

Concentration–response curves to bradykinin in the isolated mouse ductus arteriosus. Vessels were pretreated with indomethacin (2.8 μM) plus other inhibitors and excess potassium in various combinations. (a) WT, L-NAME (100 μM, n=5), ZnPP (10 μM, n=6), L-NAME/Znpp (n=4) (b) WT, L-NAME/ZnPP alone (n=4) and with K⁺ 20 mM (n=5) or K⁺ 55 mM (n=4). (c) WT, L-NAME/ZnPP alone (n=4) and with TRAM-34 (1 μM)/apamin (0.2 μM) (n=4). (d) eNOS−/−, ZnPP alone (n=4) and with TRAM-34/apamin (n=3). Bradykinin curve during treatment with L-NAME/ZnPP is the same as in (a), (b) and (c). Values of wall tension (mN mm⁻¹) before bradykinin under the various conditions are given in Table 2. Progression of concentration-dependent responses to bradykinin is significant for L-NAME-/ZnPP-treated WT preparations, in the absence and presence of K⁺ 20 mM and for ZnPP-treated eNOS−/− preparations (P<0.001, ANOVA). In each panel, bradykinin curves marked with an asterisk differ from the other curves (P=0.001, or better). Where necessary, points have been offset to improve visibility and any missing s.e. bar is within the size of the symbol.