Blood flow elevation increases V̇O2 maximum during repetitive tetanic contractions of dog muscle in situ

W. F. Brechue, Bill Ameredes, G. M. Andrew, W. N. Stainsby

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Blood flow through the gastrocnemius-plantaris muscle of the dog in situ was increased by a pump in the arterial supply during a 30-min period of 1/s isotonic tetanic contractions. Compared with a control series of experiments with normoxemia and spontaneous flow, the pump increased flow 84%, from 1.51 ± 0.08 to 2.78 ± 0.15 ml · g-1 · min-1. The perfusion pressure was increased from 125 to 196 mmHg. The pump hyperemia increased maximal O2 uptake (V̇O2) at 5 min of contractions by 31%, from 8.97 ± 0.44 to 12.89 ± 0.30 μmol · g-1 · min-1. The extraction was decreased, and venous PO2 (PV(O2)) was increased. Fatigue, measured as a drop in power production from the highest level at 10 s to 30 min, was 49% during pump hyperemia and 54% in the control conditions. V̇O2 decreased 30% from the 5-min value to the 30-min value with pump hyperemia and 28% over the same time in the control conditions. At maximal V̇O2, the ratio V̇O2/Pv(O2) was increased by pump hyperemia compared with control conditions, suggesting an increased O2 diffusing conductance of the muscles. We conclude that the elevated perfusion pressure of pump hyperemia increased flow to raise maximal V̇O2 mainly in areas of the muscle that had restricted flow under control conditions.

Original languageEnglish (US)
Pages (from-to)1499-1503
Number of pages5
JournalJournal of Applied Physiology
Volume74
Issue number4
StatePublished - 1993
Externally publishedYes

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Keywords

  • isotonic contractions
  • muscle metabolism
  • pump hyperemia

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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