Endothelin is a potent constrictor of the lamb ductus arteriosus.
Endothelin was tested on isolated ductus arteriosus preparations from mature fetal lambs. At low PO2 (18-24 Torr; 1 Torr = 133.3 Pa), the compound constricted the vessel dose-dependently over the range from about 10(-10) to 10(-7) M. The contraction was sustained and did not subside even after an extended period of washing. Endothelin was also effective on tissues (PO2,217-231 Torr; indomethacin, 2.8 X 10(-6) M) that had been completely relaxed with CO (CO/O2 ratio, 0.28). CO treatment interferes with a cytochrome P-450 mechanism, which is considered crucial for the contractile response of the vessel to oxygen. These findings are consistent with a role of endothelin in the closure of the ductus arteriosus at birth.
Coceani
F
F
Research Institute, Hospital for Sick Children, Toronto, Ont., Canada.
Armstrong
C
C
Kelsey
L
L
D000818:Animals; D004373:Ductus Arteriosus / Q000187:drug effects / Q000196:embryology / Q000502:physiology; D005314:Embryonic and Fetal Development; D016232:Endothelins; D010100:Oxygen / Q000502:physiology; D010313:Partial Pressure; D010455:Peptides / Q000494:pharmacology*; D012756:Sheep; D014661:Vasoconstriction / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D016232:Endothelins; D010455:Peptides; D014662:Vasoconstrictor Agents; D010100:Oxygen