Ductus arteriosus: involvement of a sarcolemmal cytochrome P-450 in O2 constriction?

Can J Physiol Pharmacol. 1989 Nov;67(11):1448-50. doi: 10.1139/y89-232.


Our previous studies implicate a cytochrome P-450-based mechanism in the constrictor response of the ductus arteriosus to oxygen. The present experiments were conducted on saponin-skinned strips of ductal muscle from mature fetal lambs to determine the location, sarcolemmal versus intracellular, of this cytochrome and to obtain a better insight into the sequence of events underlying the action of oxygen. Skinned preparations contracted to free Ca2+ over the range between 0.1 and 5-10 microM (pCa 7 to 5). In contrast, oxygen (PO2, 608-690 Torr; 1 Torr = 133.3 Pa) had no significant effect, both in the absence and presence of 10 microM calcium. Carbon monoxide, tested as pure CO or a CO-O2 mixture (ratio 0.28), did not relax preparations maximally contracted with calcium. These findings indicate that oxygen exerts its effect on the plasma membrane of ductus muscle cells and that a membrane-bound cytochrome P-450 mechanism likely functions as the signal transducer for oxygen in the formation of a constrictor agent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cytochrome P-450 Enzyme System / metabolism*
  • Ductus Arteriosus / enzymology*
  • Female
  • Fetus / physiology
  • Muscle Contraction / drug effects
  • Muscle, Smooth, Vascular / drug effects*
  • Oxygen / pharmacology*
  • Pregnancy
  • Saponins / pharmacology
  • Sarcolemma / enzymology*
  • Sheep


  • Saponins
  • Cytochrome P-450 Enzyme System
  • Oxygen