Premium
Regional differences in vascular sympathetic innervation are maintained in aging C57Bl/6 mice
Author(s) -
Long Jennifer B.,
Segal Steven S.
Publication year - 2006
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.20.4.a271-d
Subject(s) - anatomy , magnification , tyrosine hydroxylase , mesenteric arteries , sympathetic innervation , blood flow , blood vessel , carotid arteries , sympathetic nervous system , artery , medicine , biology , immunohistochemistry , blood pressure , computer science , computer vision
Sympathetic innervation is integral to regional blood flow control. It is unknown whether regional differences in the density of sympathetic innervation change with aging. We investigated these relationships using male C57Bl/6 mice (‘Young’ = 3 mo, n=5; ‘Old’ = 20 mo, n=5). Carotid and femoral conduit arteries, feed arteries of the gracilis muscle, and second‐order mesenteric arteries and veins were isolated, secured at in situ dimensions and immunolabeled for tyrosine hydroxylase. Total nerve length and surface area for the superficial half of each vessel segment (length = 400–700 μm) was quantified using 3‐D mapping (Neurolucida) of fluorescent images (magnification, 886X; ~1 μm resolution) to calculate innervation density (total nerve length/total surface area; μm/μm 2 ). Carotid arteries were devoid of labeling. In Young, mesenteric and femoral arteries were surrounded by dense nerve plexuses along the vessel and had the highest innervation densities (0.075 ± 0.002 and 0.079 ± 0.003, respectively). Innervation densities were ~40% lower (P < 0.05) for mesenteric veins (0.052 ± 0.002) and gracilis feed arteries (0.040 ± 0.002), with nerve fibers distributed sparsely along vessels. Old were not different from Young for any vessel. These findings demonstrate regional variation in the density of sympathetic innervation that is unaffected by aging (through 20 mo) in mice. We conclude that regional differences in vascular sympathetic innervation remain central to cardiovascular regulation during physical stress. (Support: R21 AG19347 and T32 GM07527)