Abstract
The purpose of our investigation was to assess the role of the endothelium in the vasomotor effects of leukotrienes. Norepinephrine-preconstricted rings isolated from guinea pig main pulmonary artery and thoraic aorta responded to LTC 4 and LTD 4 with a concentration-dependent relaxation. In endothelium-denuded rings, both LTC 4 and LTD 4 caused a concentration-dependent contraction. The LTD 4 receptor antagonist ICI 198, 615 inhibited both LTC 4- and LTD 4-induced relaxation and contraction. Inhibition of γ-glutamyl transpeptidase with AT-125 prevented the effects of LTC 4, but not those of LTD 4. The relaxant effect of LTD 4 was not modified by indomethacin, but was abolished by methylene blue. We conclude that: 1)LTD 4 induces a receptor-mediated endothelium-dependent relaxation of cavian pulmonary artery and aorta; 2) the vasorelaxant effect of LTC 4 requires its conversion to LTD 4; 3) the vasorelaxant effect of LTD 4 is unrelated to PGI 2 release, and is probably due to the release of an “EDRF”; 4) the removal of the endothelium reveals a direct receptor-mediated vasoconstricting effect of leukotrienes.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
