Oxygen-induced tension in the sheep ductus arteriosus: Effects of gestation on potassium and calcium channel regulation

Nahid Waleh, Jeff Reese, Hiroki Kajino, Christine Roman, Steven Seidner, Donald McCurnin, Ronald I. Clyman

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Compared with the full-term ductus arteriosus, the premature ductus is less likely to constrict when exposed to postnatal oxygen concentrations. We used isolated fetal sheep ductus arteriosus (pretreated with inhibitors of prostaglandin and nitric oxide production) to determine whether changes in K+- and CaL-channel activity could account for the developmental differences in oxygen-induced tension. In the mature ductus, KV-channels appear to be the only K+-channels that oppose ductus tension. Oxygen concentrations between (2% and 15%) inhibit K V-channel activity, which increases the CaL-channel- mediated increase in tension. Low oxygen concentrations have a direct inhibitory effect on CaL-channel activity in the immature ductus; this is not the case in the mature ductus. In the immature ductus, three different K +-channel activities (KV, KCa, and K ATP) oppose ductus tension and contribute to its decreased tone. Oxygen inhibits the activities of all three K+-channels. The inhibitory effects of the three K+-channel activities decline with advancing gestation. The decline in K+-channel activity is not due to decreased K+-channel expression. Super-physiologic oxygen concentrations (≥30% O2) constrict the ductus by using calcium-dependent pathways that are independent of K+- and Ca L-channel activities. Superphysiologic oxygen concentrations eliminate the difference in tensions between the two age groups.

Original languageEnglish (US)
Pages (from-to)285-290
Number of pages6
JournalPediatric Research
Volume65
Issue number3
DOIs
StatePublished - Mar 2009

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health

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