Aging is associated with altered vasodilator kinetics in dynamically contracting muscle: role of nitric oxide

Darren P Casey; Sushant M Ranadive; Michael J Joyner

doi:10.1152/japplphysiol.00787.2014

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Aging is associated with altered vasodilator kinetics in dynamically contracting muscle: role of nitric oxide

Journal article

Open access

Peer reviewed

Aging is associated with altered vasodilator kinetics in dynamically contracting muscle: role of nitric oxide

Darren P Casey, Sushant M Ranadive and Michael J Joyner

Journal of applied physiology (1985), Vol.119(3), pp.232-241

08/01/2015

DOI: 10.1152/japplphysiol.00787.2014

PMCID: PMC4526703

PMID: 26023230

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Abstract

We tested the hypothesis that aging would be associated with slowed vasodilator kinetics in contracting muscle in part due to a reduced nitric oxide (NO) bioavailability. Young (n = 10; 24 ± 2 yr) and older (n = 10; 67 ± 2 yr) adults performed rhythmic forearm exercise (4 min each) at 10, 20, and 30% of max during saline infusion (control) and NO synthase (NOS) inhibition. Brachial artery diameter and velocities were measured using Doppler ultrasound. Forearm vascular conductance (FVC) was calculated for each duty cycle (1 s contraction/2 s relaxation) from forearm blood flow (FBF; ml/min) and blood pressure (mmHg) and fit with a monoexponential model. The main parameters derived from the model were the amplitude of the FBF and FVC response and the number of duty cycles for FBF and FVC to change 63% of the steady-state amplitude (τFBF and τFVC). Under control conditions 1) the amplitude of the FVC response at 30% maximal voluntary contraction (MVC) was lower in older compared with young adults (319 ± 33 vs. 462 ± 52 ml·min(-1)·100 mmHg(-1); P < 0.05) and 2) τFVC was slower in older (10 ± 1, 13 ± 1, and 15 ± 1 duty cycles) compared with young (6 ± 1, 9 ± 1, and 11 ± 1 duty cycles) adults at all intensities (P < 0.05). In young adults, NOS inhibition blunted the amplitude of the FVC response at 30% MVC and prolonged the τFVC at all intensities (10 ± 2, 12 ± 1, and 16 ± 2 duty cycles; P < 0.05), whereas it did not change in older adults. Our data indicate that the blood flow and vasodilator kinetics in exercising muscle are altered with aging possibly due to blunted NO signaling.

Humans

Male

Muscle, Skeletal - physiology

Aging - physiology

Muscle Contraction - physiology

Adult

Female

Aged

Exercise - physiology

Kinetics

Vasodilation - physiology

Nitric Oxide - metabolism

Blood Flow Velocity - physiology

Muscle, Skeletal - blood supply

Details

Title: Subtitle: Aging is associated with altered vasodilator kinetics in dynamically contracting muscle: role of nitric oxide
Creators: Darren P Casey - Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa; and darren-casey@uiowa.edu
Sushant M Ranadive - Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
Michael J Joyner - Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota
Resource Type: Journal article
Publication Details: Journal of applied physiology (1985), Vol.119(3), pp.232-241
DOI: 10.1152/japplphysiol.00787.2014
PMID: 26023230
PMCID: PMC4526703
NLM abbreviation: J Appl Physiol (1985)
ISSN: 8750-7587
eISSN: 1522-1601
Publisher: United States
Grant note: HL-46493 / NHLBI NIH HHS HL-119337 / NHLBI NIH HHS UL1 TR000135 / NCATS NIH HHS HL-105467 / NHLBI NIH HHS
Language: English
Date published: 08/01/2015
Academic Unit: Physical Therapy and Rehabilitation Science; Fraternal Order of Eagles Diabetes Research Center
Record Identifier: 9984046923802771

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