Rapid vasodilation in response to a brief tetanic muscle contraction

Jay S. Naik, Zoran Valic, John B. Buckwalter, Philip S. Clifford

Research output: Contribution to journalArticlepeer-review

71 Scopus citations

Abstract

To test the hypothesis that vasodilation occurs because of the release of a vasoactive substance after a brief muscle contraction and to determine whether acetylcholine spillover from the motor nerve is involved in contraction-induced hyperemia, tetanic muscle contractions were produced by sciatic nerve stimulation in anesthetized dogs (n = 16), instrumented with flow probes on both external iliac arteries. A 1-s stimulation of the sciatic nerve at 1.5, 3, and 10 times motor threshold increased blood flow above baseline (P < 0.01) for 20, 25, and 30 s, respectively. Blood flow was significantly greater 1 s after the contraction ended for 3 and 10 x motor threshold (P < 0.01) and did not peak until 6-7 s after the contraction. The elevations in blood flow to a 1-s stimulation of the sciatic nerve and a 30-s train of stimulations were abolished by neuromuscular blockade (vecuronium). The delayed peak blood flow response and the prolonged hyperemia suggest that a vasoactive substance is rapidly released from the contracting skeletal muscle and can affect blood flow with removal of the mechanical constraint imposed by the contraction. In addition, acetylcholine spillover from the motor nerve is not responsible for the increase in blood flow in response to muscle contraction.

Original languageEnglish
Pages (from-to)1741-1746
Number of pages6
JournalJournal of Applied Physiology
Volume87
Issue number5
DOIs
StatePublished - Nov 1999
Externally publishedYes

Keywords

  • Acetylcholine
  • Blood flow
  • Dog
  • Exercise
  • Muscle pump
  • Skeletal muscle

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