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Vascular Effects of Prostacyclin and L‐NMMA in Aging
Author(s) -
Nicholson Wayne Thomas,
Vaa Brianna E,
Hesse Christiane,
Somaraju Lakshmi P,
Pike Tasha L,
Curry Timothy B,
Dietz Niki M,
Eisenach John H,
Joyner Michael J
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.967.15
Subject(s) - prostacyclin , medicine , forearm , dilator , sodium nitroprusside , brachial artery , omega n methylarginine , endocrinology , cardiology , blood pressure , nitric oxide , nitric oxide synthase , surgery
The vascular effects of prostacyclin and contribution of endothelial derived nitric oxide (NO) to prostacyclin mediated dilation are unknown in aging. A pilot study was performed in healthy older subjects (n=6, 61–73 years old) and younger controls (n=6, 19–45 years old) that were matched for BMI. Subjects underwent brachial artery catheterization and received escalating doses of epoprostenol (PGI 2 2.5, 5, 10 ng/100ml forearm tissue/min) followed by sodium nitroprusside (SNP 0.25, 0.5, 1 mcg/100ml forearm tissue/min) after PGI 2 washout. SNP and PGI 2 were repeated after NO synthase inhibition with N G ‐Monomethyl‐L arginine acetate (L‐NMMA 1mg/min after 50mg load). Using venous occlusion plethysmography, forearm vascular conductance (FVC) was calculated using mean arterial pressure (MAP), as FVC= (FBF/MAP X 100). Percent change in FVC from baseline after PGI 2 was lower in the aging individuals (47, 160, 227 % change FVC) compared to younger controls (85, 218, 327 %change FVC) (p=0.039), L‐NMMA reduced baseline FVC similarly, and the dilator response to PGI 2 was no longer significant between groups. SNP effects were not significant between groups and unaffected by L‐NMMA. This data suggests a reduced effect to prostacyclin in the aging individual may be due to a reduction in the contribution of endothelial derived NO. Support provided by HL‐46493 and UL1‐RR24150.