OBJECTIVE: Our objective was to examine the role of the endothelium in maintaining vascular tone in the basal as well as in the contracted state during aging. DESIGN/PARTICIPANTS: Responses to brachial artery infusion of acetylcholine in presence and absence of NG-nitro-L-arginine methyl ester (L-NAME) and to angiotensin II were studied in 11 young and 12 old white subjects. MEASUREMENTS: Strain gauge plethysmography was used to measure forearm vascular resistance (FVR). The dose of acetylcholine at 50% maximal observed decrease in forearm vascular resistance (EC50) was significantly higher (11.0 +/- 1.59 vs 7.07 +/- .65 microg/min, respectively; mean +/-SEM; P < .05) and the FVR at maximal acetylcholine effect (Emax) remained greater (12.6 +/- 1.75 vs 7.15 +/- 1.25 mm Hg/100 mL tissue volume/min; P < .02) in old compared with young subjects. Acetylcholine effect was significantly reversed by concomitant administration of L-NAME, as indicated by the increase in EC50 (old, 20.2 +/- 3.69; young, 11.9 +/- 1.68 microg/min). RESULTS: There was no age-related difference in sodium nitroprusside-induced decrease in FVR. The EC50 and Emax for angiotensin II-mediated increase in FVR were 7.87 +/- 1.15 and 8.36 +/- 1.00 ng/min (EC50) and 5.30 +/- .67 vs 6.56 +/-1.25 mm Hg/100 mL tissue volume/min (Emax), and these were not different in old and young subjects, respectively. CONCLUSIONS: These data indicate that aging is associated with impaired endothelial- dependent vascular relaxation and that this is selective, with no age-related change in endothelial-independent vascular relaxation or angiotensin II-mediated vascular contraction.
OBJECTIVE: Our objective was to examine the role of the endothelium in maintaining vascular tone in the basal as well as in the contracted state during aging. DESIGN/PARTICIPANTS: Responses to brachial artery infusion of acetylcholine in presence and absence of NG-nitro-L-arginine methyl ester (L-NAME) and to angiotensin II were studied in 11 young and 12 old white subjects. MEASUREMENTS: Strain gauge plethysmography was used to measure forearm vascular resistance (FVR). The dose of acetylcholine at 50% maximal observed decrease in forearm vascular resistance (EC50) was significantly higher (11.0 +/- 1.59 vs 7.07 +/- .65 microg/min, respectively; mean +/-SEM; P < .05) and the FVR at maximal acetylcholine effect (Emax) remained greater (12.6 +/- 1.75 vs 7.15 +/- 1.25 mm Hg/100 mL tissue volume/min; P < .02) in old compared with young subjects. Acetylcholine effect was significantly reversed by concomitant administration of L-NAME, as indicated by the increase in EC50 (old, 20.2 +/- 3.69; young, 11.9 +/- 1.68 microg/min). RESULTS: There was no age-related difference in sodium nitroprusside-induced decrease in FVR. The EC50 and Emax for angiotensin II-mediated increase in FVR were 7.87 +/- 1.15 and 8.36 +/- 1.00 ng/min (EC50) and 5.30 +/- .67 vs 6.56 +/-1.25 mm Hg/100 mL tissue volume/min (Emax), and these were not different in old and young subjects, respectively. CONCLUSIONS: These data indicate that aging is associated with impaired endothelial- dependent vascular relaxation and that this is selective, with no age-related change in endothelial-independent vascular relaxation or angiotensin II-mediated vascular contraction.
Authors: Carmen Castillo; Veronica Salazar; Carmen Ariznavarreta; Elena Vara; Jesus A F Tresguerres Journal: Endocrine Date: 2005-02 Impact factor: 3.633
Authors: Jacqueline K Limberg; Trent D Evans; David F Pegelow; Marlowe W Eldridge; Joshua J Sebranek; Lester T Proctor; William G Schrage Journal: Eur J Appl Physiol Date: 2011-12-25 Impact factor: 3.078
Authors: Nina A Mikirova; James A Jackson; Ron Hunninghake; Julian Kenyon; Kyle W H Chan; Cathy A Swindlehurst; Boris Minev; Amit N Patel; Michael P Murphy; Leonard Smith; Doru T Alexandrescu; Thomas E Ichim; Neil H Riordan Journal: J Transl Med Date: 2009-12-15 Impact factor: 5.531