TY - JOUR
T1 - Rapid vasodilation in response to a brief tetanic muscle contraction
AU - Naik, Jay S.
AU - Valic, Zoran
AU - Buckwalter, John B.
AU - Clifford, Philip S.
PY - 1999/11
Y1 - 1999/11
N2 - 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.
AB - 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.
KW - Acetylcholine
KW - Blood flow
KW - Dog
KW - Exercise
KW - Muscle pump
KW - Skeletal muscle
UR - http://www.scopus.com/inward/record.url?scp=0032748437&partnerID=8YFLogxK
U2 - 10.1152/jappl.1999.87.5.1741
DO - 10.1152/jappl.1999.87.5.1741
M3 - Article
C2 - 10562617
AN - SCOPUS:0032748437
SN - 8750-7587
VL - 87
SP - 1741
EP - 1746
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 5
ER -