Evidence for microvascular dysfunction after prenatal dexamethasone at 0.7, 0.75, and 0.8 gestation in sheep

Judit Molnar, Mark J.M. Nijland, David C. Howe, Peter W. Nathanielsz

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Dexamethasone (DM) was administered to pregnant ewes as three weekly courses of four injections of 2 mg at 12-h intervals. DM (n = 7) or saline (n = 7) was given starting at 103 days of gestation (dGA; term ∼149 days). Fetal femoral arteries (∼300-μm internal diameter) were evaluated using wire myography at 119 dGA. DM-exposed fetuses were significantly smaller than saline-exposed fetuses. DM exposure increased maximal contraction to 125 mM KCl, and maximum tension developed along with sensitivity to endothelin-1 and relaxation to bradykinin. Preincubation with the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester shifted the dose-response curves to endothelin-1 and acetylcholine to the right in controls but not in the DM-exposed group. Relaxation to acetylcholine and to the nitric oxide donor sodium nitroprusside was similar in both groups. The combination of enhanced endothelin-induced vasoconstriction, abnormal endothelium-dependent relaxation, and normal endothelium-independent relaxation indicates microvessel dysfunction following antenatal DM administration. Because such dysfunction is associated with several forms of adult hypertension, our results indicate the potential for consequences of antenatal glucocorticoid exposure on adult cardiovascular health.

Original languageEnglish (US)
Pages (from-to)R561-R567
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume283
Issue number3 52-3
DOIs
StatePublished - Sep 2002

Keywords

  • Acetylcholine
  • Bradykinin
  • Endothelin-1
  • N-nitro-L-arginine methyl ester
  • Nitric oxide
  • Wire myography

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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