Prostanoid involvement in the relaxation of in vitro mesenteric artery by bradykinin and des-Arg9-bradykinin.

Bradykinin (BK), des-Arg9-BK, prostaglandin E2, prostacyclin and angiotensin II all produced concentration-related relaxation of rabbit in vitro de-endothelialized superior mesenteric arterial ring preparations precontracted with phenylephrine. Responses were reproducible at time 1 h and 4 h after setting up the preparations. The cyclo-oxygenase inhibitor indomethacin (2.8 x 10(-6) M) and the protein synthesis inhibitor cycloheximide (7.2 x 10(-5) M) introduced at t = 0 h inhibited relaxant responses to BK, des-Arg9-BK and angiotensin II, but not prostaglandin E2 or prostacyclin at t = 1 h and t = 4 h. Cycloheximide and indomethacin applied to the tissues at t = 3 h inhibited relaxant responses to BK, des-Arg9-BK and angiotensin II (but not prostaglandin E2 or prostacyclin) at t = 4 h. It is concluded that BK, des-Arg9-BK and angiotensin II (but not prostaglandin E2 or prostacyclin) induced relaxant responses of the in vitro rabbit mesenteric artery are dependent upon the generation of a relaxant prostanoid from the tissue and that cycloheximide produces its effect in this tissue by a mechanism similar to that seen with indomethacin.