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Dietary Nitrate Enhances Peak Power in Aged Murine Diaphragm
Author(s) -
Kelley Rachel C.,
Kumar Ravi A.,
Hahn Dongwoo,
Ferreira Leonardo F.
Publication year - 2018
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.2018.32.1_supplement.852.4
Subject(s) - nitric oxide , diaphragm (acoustics) , medicine , isometric exercise , nitrate , chemistry , endocrinology , sodium nitrate , zoology , anabolism , biology , physics , organic chemistry , acoustics , loudspeaker
Inspiratory muscle (diaphragm) function declines with age. Aging‐related diaphragm atrophy and/or dysfunction likely contribute to impaired airway clearance and exercise intolerance in the elderly. The goal of our current study was to determine the therapeutic potential of dietary nitrate supplementation in aged diaphragm. Aging decreases the availability of nitric oxide (NO), but supplementation with NO precursors (e.g., sodium nitrate, beetroot juice, arginine) may augment NO production. Previous studies have shown that dietary nitrate may improve skeletal muscle contractile efficiency, mitochondrial function, and anabolism by enhancing NO's vasodilatory and/or cell signaling effects. In this study, old (n=14, 24 months old) mice received sodium nitrate (NaNO 3 , 1 mM) in drinking water or vehicle (deionized H 2 O) ad libitum for a total of 14 days. After treatment, diaphragm function was evaluated using isolated muscle bundles. Dietary nitrate supplementation did not result in improvements in maximal isometric force (control: 20.5 ± 2.9 vs NaNO 3 : 22 ± 3.4 N/cm 2 ), twitch force (control: 3 ± 0.5 vs NaNO 3 : 3.6 ± 0.6 N/cm 2 ), time‐to‐peak tension (control: 16.7 ± 0.5 vs NaNO 3 : 15.3 ± 1.7 ms), ½ relaxation time (control: 14.1 ± 1.8 vs NaNO 3 : 14.3 ± 2 ms), or maximal shortening velocity (control: 7 ± 3.1 vs NaNO 3 : 8.1 ± 1.2 L o /s). However, dietary nitrate supplementation did significantly increase peak power from 161.4 ± 32.3 W/kg in controls to 224.8 ± 35.5 W/kg in supplemented mice (p < 0.05). Ventilation during exercise as well as non‐ventilatory behaviors needed for airway clearance, such as coughing and sneezing, require rapid, forceful contractions of the diaphragm. Therefore, our results suggest that supplementation with dietary nitrate may increase peak power and thus be of benefit in aging populations. Support or Funding Information NIA 1R03AG04040001A1 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .