Abstract
Endothelium-derived nitric oxide (EDNO) modulates the responses of pulmonary vasculature. The present study was designed to determine EDNO-mediated responses of pulmonary arteries (PA) of term fetal, newborn, and adult sheep. Vessel rings were suspended in organ chambers and their isometric tension was recorded. In vessels preconstricted with endothelin-1, acetylcholine had no effect on fetal PA but caused a greater endothelium-dependent relaxation in adult PA than in newborn PA. In vessels without endothelium, nitric oxide and 8-bromo-cGMP caused greater relaxation in adult PA than in newborn PA while causing the least relaxation in fetal PA. Acetylcholine had no effect on cGMP content in fetal PA but caused a greater endothelium-dependent increase in cGMP content in adult PA than in newborn PA. In vessels without endothelium, nitric oxide caused a smaller increase in cGMP content of fetal PA than of newborn PA while causing the greatest increase in cGMP of adult PA. These results demonstrate an age-dependent increase in EDNO-mediated responses of ovine pulmonary arteries. A change in receptor and/or receptor coupling, in soluble guanylate cyclase activity, and in cGMP responsiveness of vascular smooth muscle may contribute to the phenomenon.
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.
