Abstract
It has been suggested that ineffective constriection in response to an increase in PO2 is the primary cause for delayed closure of the ductus arteriosus in preterm infants. We studied the isometric contractile effects of increased PO2 and indomethacin on isolated rings of lamb ductus arteriosus from animals of different gestational ages (87-150 days, term 150 days). Only rings from animals <110 days have a significantly smaller O2-induced contraction (2.53±.3 g/mm2, n=16) when compared with rings from animals near term (4.59±.69 g/mm2, n=9). O2-contracted rings from all gestational ages contract further upon addition of 1 μg/m1 indomethacin. Rings from animals <110 days have a significantly larger indomethacin-induced contraction (110±.17 g/mm2 , n=16) than vessels near term (0.52±.12 g/mm2, n=9). Vessels <110 days have a significantly reduced response to O2 in comparison with those from older animals; however, inhibition of prostaglandin production in rings <110 days resulted in a total combined O2 and indomethacin induced tension that is not significantly different from the O2 or combined O2 and indomethacin-induced tension developed in rings from animals near term. This is consistent with the hypothesis that, early during gestation, endogenous prostaglandins inhibit the vessel's ability to contract in response to O2. These observations are also consistent with the ability of indomethacin to constrict the patent ductus arteriosus in preterm infants.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Clyman, R., Heymann, M. & Rudolph, A. 92 DUCTUS ARTERIOSUS: DEVELOPMENTAL RESPONSE TO O2 AND INDOMETHACIN. Pediatr Res 12 (Suppl 4), 379 (1978). https://doi.org/10.1203/00006450-197804001-00097
Issue Date:
DOI: https://doi.org/10.1203/00006450-197804001-00097