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DECREASED TEMPORAL ACTIVITY AT MICROVASCULAR BIFURCATIONS EXACERBATES PERFUSION HETEROGENEITY IN SKELETAL MUSCLE IN THE METABOLIC SYNDROME
Author(s) -
Butcher Joshua,
Goodwill Adam,
Beard Daniel,
Frisbee Jefferson
Publication year - 2012
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.26.1_supplement.860.12
Subject(s) - perfusion , microcirculation , medicine , phentolamine , cardiology , skeletal muscle , cremaster muscle , constriction , endocrinology , ischemia , stimulation
We have demonstrated that peripheral vascular disease (PVD) in obese Zucker rats (OZR) is due to increased perfusion heterogeneity at successive microvascular bifurcations. This increased heterogeneity (γ) is longitudinally present in the microvascular network, but reflects differential contributions and effects of adrenergic constriction, elevated ROS and increased TxA 2 production. The cumulative impact of increased γ is a more heterogeneous distribution of perfusion between terminal arterioles, leading to greater tissue ischemia. However, increased temporal switching at bifurcations should compensate for the increased γ, and minimize perfusion impairments. In cremaster muscle, we determined that temporal activity (the cumulative sum of absolute differences between successive values of γ, taken every 15 seconds for 5 minutes) was lower in OZR than controls, and this difference was present in both proximal (1A‐2A) and distal (3A‐4A) bifurcations. While adrenoreceptor blockade (phentolamine) improved outcomes proximally in OZR, this was without impact in the distal microcirculation, where only interventions against ROS (TEMPOL) and TxA 2 (SQ‐29548) were effective. These data suggest that reduced temporal activity at microvascular bifurcations in OZR accentuates the effects of increased γ, exacerbating perfusion‐based elements underlying PVD. (NIH RR2465AR, T32 HL90610, AHA 0740129N)