title: In vitro oxygen exposure promotes maturation of the oxygen sensitive contraction in pre-term chicken ductus arteriosus.
abstract: The ductus arteriosus (DA) are O2-sensitive, embryonic blood vessels that serve as a right-to-left shunt in developing avian embryos. Prior to internal pipping, the chicken DA produces a weak O2-induced contraction. During hatching, the O2-sensitivity of the avian DA vessels increases significantly. To see if we could accelerate the maturation of chicken DA O2-sensitivity, we exposed the vessel in vitro to elevated O2 (25 kPa) for 3-h prior to internal pipping on day 19 of incubation. The DA initially responded to increasing O2 with a weak contraction (0.15±0.04 N/m) that significantly increased in strength (0.63±0.06 N/m) during 3-h 25 kPa O2 exposure. A tonic influence of nitric oxide, not present at low O2, appeared during the 3-h 25 kPa O2 exposure. The long-term O2-induced contraction was mediated by both L-type Ca(2+) channels and internal Ca(2+) stores. The Rho-kinase pathway inhibitors Y-27632 and fasudil produced significant relaxation, suggesting a role for Ca(2+) sensitization in the contractile response to the 3h of elevated O2. While the day 19 DA initially exhibited an immature contractile response to O2, maturation of the pathways regulating O2-induced contraction was accelerated by exposure to 25 kPa O2, producing contractions similar in magnitude to those found during the final stage of hatching. This suggests that maturation of O2-sensitivity may be accelerated in vivo by increasing arterial O2 levels.
authors.affiliation: Department of Biological Science, 1155 Union Circle #305220, University of North Texas, Denton, TX 76203, USA.
authors.forename: Henry
authors.initials: H
authors.lastname: Greyner
authors.affiliation: Department of Biological Science, 1155 Union Circle #305220, University of North Texas, Denton, TX 76203, USA. Electronic address: edzial@unt.edu.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Dzialowski
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000577:Amides / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000378:metabolism; D002642:Chick Embryo; D002645:Chickens; D015232:Dinoprostone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004373:Ductus Arteriosus / Q000187:drug effects* / Q000196:embryology / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology*; D011725:Pyridines / Q000494:pharmacology; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000577:Amides; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D004791:Enzyme Inhibitors; D011725:Pyridines; C108830:Y 27632; D009569:Nitric Oxide; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054460:rho-Associated Kinases; D009543:Nifedipine; D015232:Dinoprostone; C049347:fasudil; D010100:Oxygen; D002118:Calcium
keywords: Chicken; Ductus arteriosus; Oxygen; Rho kinase