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Non ‐ adrenergic receptor mediated tonic vasoconstriction in skeletal muscle does not change with age
Author(s) -
DeLorey Darren S,
Buckwalter John B,
Mittelstadt Scott W,
Kluess Heidi A,
Clifford Philip S
Publication year - 2009
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.23.1_supplement.787.11
Subject(s) - medicine , endocrinology , ppads , vasoconstriction , skeletal muscle , neuropeptide y receptor , bolus (digestion) , receptor , purinergic receptor , neuropeptide
Sympathetic co‐transmitter release may increase with aging. Thus, non‐adrenergic receptor mediated vasoconstriction may assume a greater role in the control of skeletal muscle vascular tone with aging. The purpose of this study was to investigate the effect of age on neuropeptide Y ‐ Y 1 (NPY) and purinergic (P2X) receptor mediated restraint of skeletal muscle blood flow. Young (n = 6; 22 ± 3 months) and old (n = 7; 119 ± 22 months) beagles were studied. Selective NPY (BIBP‐3226; 2.5 mg bolus) and P2X receptor (PPADS; 40 mg bolus) antagonists were infused at rest, and during treadmill running at 2.5 miles/h and 4 miles/h with 2.5% grade. Hindlimb blood flow (HBF) and mean arterial pressure (MAP) were monitored continuously and vascular conductance (VC) was calculated. Infusion of BIBP‐3226 resulted in similar increases in VC in young and old beagles at rest (Young 137 ± 64 % ; Old:, 96 ± 54 % ) and at 2.5 miles/h (Young 56 ± 39 % ; Old:, 52 ± 24 %) and 4 miles/h with 2.5% grade (Young: 45 ± 24 %; Old: 39 ± 35 %). PPADS infusion also produced similar increases in VC in young and old beagles at rest (Young: 88 ± 35 %; Old: 164 ± 143 %) and at 2.5 miles/h (Young: 47 ± 43 %; Old: 31 ± 27 %) and 4 miles/h with 2.5% grade (Young: 26 ± 33 %; Old: ‐13 ± 21 %). These results demonstrate that NPY and P2X receptor mediated restraint of skeletal muscle blood flow does not increase in older compared to young beagles at rest or during dynamic exercise.