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Myoendothelial Contacts Within the Skeletal Muscle Arterial Network: A Potential Mediator for Divergent Control of Vascular Tone
Author(s) -
Kirby Brett S,
Bruhl Allison,
Earley Scott
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.1058.4
Subject(s) - anatomy , vasodilation , skeletal muscle , hyperpolarization (physics) , vascular smooth muscle , artery , hindlimb , internal elastic lamina , medicine , biology , chemistry , smooth muscle , organic chemistry , nuclear magnetic resonance spectroscopy
Holes within the internal elastic lamina (IEL) of blood vessels, referred to as myoendothelial contacts (MECs), are sites of fenestration allowing for passage of diffusible vasoactive substances and interface of endothelial cell membrane projections with underlying vascular smooth muscle. Endothelial projections are sites of dynamic Ca 2+ events leading to endothelial cell hyperpolarization‐mediated relaxation and the activity of these events increase as vessel diameter decreases. Given that arterioles are the primary site of vascular resistance within skeletal muscle, we tested the hypothesis that fenestration within the IEL would be greater in distal vs. proximal arteries of the skeletal muscle arterial network. Popliteal arteries, subsequent gastrocnemius feed arteries, and intramuscular 1A arterioles from the Sprague Dawley rat hindlimb were isolated, cut and fixed longitudinally, and imaged using confocal microscopy. Quantitative analysis revealed a larger MEC total area of 1A vs. feed and popliteal arteries (20.7% vs. 5.8% and 2.8%; N = 10 images/artery), due to a noticeably greater average size of MEC (39.6μm 2 vs. 11.1μm 2 and 7.6μm 2 ). These initial observations highlight the superior MEC area of intramuscular arteries and are suggestive that the anatomical architecture for distinct vasodilatory signaling is present. Supported by RO1HL091905