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Local H 1 ‐and H 2 ‐receptor blockade blunts postexercise blood flow in the vastus lateralis
Author(s) -
Pellinger Thomas K,
Simmons Grant H,
Halliwill John R
Publication year - 2008
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.22.1_supplement.957.22
Subject(s) - microdialysis , blockade , skeletal muscle , medicine , endocrinology , chemistry , receptor , central nervous system
Orally administered histamine H 1 ‐ and H 2 ‐receptor blockade blunts the sustained (90 min) hyperemia present in the previously exercised limbs of humans following dynamic exercise. Our aim was to determine if this postexercise hyperemic response could be prevented by local H 1 ‐ and H 2 ‐receptor blockade administered via skeletal muscle microdialysis. Thus, we tested the hypothesis that postexercise ethanol outflow/inflow ratios (an inverse surrogate of local blood flow) would be higher in sites that received H 1 ‐ and H 2 ‐receptor blockade versus control sites. Four microdialysis probes were inserted into the vastus lateralis muscle of five healthy subjects (21–26 yrs) immediately after 60 min of upright cycling at 60% VO 2 peak . Microdialysis probes were perfused with a modified Ringer's solution containing 5 mM ethanol. Two of the sites received H 1 ‐ and H 2 ‐receptor antagonists (1 mM pyrilamine/3 mM cimetidine) and two sites served as controls. Consistent with our hypothesis, one hour after exercise, the outflow/inflow ratio was 0.48 ± 0.02 in blockade sites versus 0.41 ± 0.03 in control sites ( P = 0.042). In addition, three subjects underwent a sham protocol (no exercise) in which blockade did not affect the ethanol outflow/inflow ratio ( P ≥ 0.143). These results suggest that local H 1 ‐ and H 2 ‐receptors in skeletal muscle contribute to postexercise hyperemia. Supported by AHA grant 555623Z and the Evonuk Foundation