AJP - Heart and Circulatory Physiology, Vol 270, Issue 1 33-H37, Copyright © 1996 by American Physiological Society
Influence of graft innervation on neovascularization of embryonic heart tissue grafted in oculo
R. J. Torry, B. J. Rongish, D. C. Tucker, D. R. Kostreva and R. J. Tomanek
Department of Anatomy, College of Medicine, University of Iowa, Iowa City 52242, USA.
We have shown that sympathetic denervation increases subendocardial
capillarity during left ventricular hypertrophy. To determine the direct
effects of sympathetic innervation on development of the coronary
microvasculature in the absence of hemodynamic load, we grafted avascular
fetal rat atrial or ventricular tissue into the anterior eye chamber of
host rats which had undergone unilateral superior cervical gangliectomies.
Innervation to the contralateral eye chamber remained intact. The grafts
were harvested 14 or 35 days later, and volume densities of blood vessels,
myocytes, and extracellular matrix were determined using standard
point-counting techniques on low-power electron micrographs. Graft
perfusion and metabolism were assessed simultaneously with thallium-201 and
2-[14C]deoxy-D-glucose uptake, respectively. Innervation did not
significantly alter the vascular volume densities or cellular composition
of atrial or ventricular tissue compared with noninnervated tissue after
either 14 or 35 days in oculo. Similarly, innervation did not significantly
alter graft perfusion or metabolism. We conclude that sympathetic
innervation does not directly influence the growth of the microvasculature
or myocardial metabolism in hemodynamically unloaded, developing heart
tissue.
