title: Antenatal betamethasone has a sex-dependent effect on the in vivo response to endothelin in adult sheep.
abstract: Antenatal steroid administration is associated with multiple cardiometabolic alterations, including hypertension; however, the mechanisms underlying this phenomenon are unclear. The aim of the present study was to ascertain, in vivo, the contribution of the endothelin system to the development of hypertension in the adult offspring and the signaling pathway involved. Pregnant sheep were treated with two doses of betamethasone (n = 23) or vehicle (n = 22) at 80 days (~0.55) gestation and allowed to deliver at term. Adult sheep were chronically instrumented under general anesthesia to place vascular catheters and a femoral artery flow probe. Blood pressure and flow were recorded continuously, and femoral artery vascular resistance was calculated before and during administration of endothelin 1 (ET-1). Selective blockers (dantrolene, BQ123, niacinamide) or saline were administered simultaneously. Betamethasone-exposed animals exhibited a significant elevation in mean blood pressure (female: 98 ± 1.8 vs. 92 ± 2.1; males: 97 ± 3.4 vs. 90 ± 2.3; mmHg; P < 0.05). ET-1 elicited a significant increase in blood pressure (F = 56.4; P < 0.001) and in vascular resistance (F = 44.3; P < 0.001) in all groups. A betamethasone effect in the vascular resistance response to ET-1 (F = 25.7; P < 0.001) was present in females only, and the effect was partially blunted by niacinamide (F = 6.6; P < 0.01). Combined administration of niacinamide and BQ123, as well as of dantrolene abolished the betamethasone effect on vascular resistance. No significant differences in mRNA expression of ET(A) or ET(B) in endothelial or smooth muscle cells of resistance-size arteries were observed. We conclude that the betamethasone effect on vascular resistance is mediated by an enhanced response to ET-1 through ET(A) receptor via the cyclic ADPR/ryanodine pathway.
authors: Perinatal Research Laboratory, Department of Obstetrics and Gynecology, Center for Research in Obstetrics and Gynecology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
authors: Jeong-Heon
authors: JH
authors: Lee
authors: Jie
authors: J
authors: Zhang
authors: Lourdes
authors: L
authors: Flores
authors: James C
authors: JC
authors: Rose
authors: G Angela
authors: GA
authors: Massmann
authors: Jorge P
authors: JP
authors: Figueroa
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001623:Betamethasone / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D003620:Dantrolene / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D065130:Endothelin A Receptor Antagonists; D016232:Endothelins / Q000494:pharmacology*; D005260:Female; D006973:Hypertension / Q000503:physiopathology; D007261:Infusions, Intra-Arterial; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D009536:Niacinamide / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis / Q000235:genetics; D010456:Peptides, Cyclic / Q000494:pharmacology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012039:Regional Blood Flow / Q000187:drug effects; D012727:Sex Characteristics; D012756:Sheep; D014655:Vascular Resistance
chemical_list: D000893:Anti-Inflammatory Agents; D065130:Endothelin A Receptor Antagonists; D016232:Endothelins; D009125:Muscle Relaxants, Central; D010456:Peptides, Cyclic; D012333:RNA, Messenger; D009536:Niacinamide; D001623:Betamethasone; D052250:Nitric Oxide Synthase Type III; D003620:Dantrolene; C072247:cyclo(Trp-Asp-Pro-Val-Leu)