Long-term electrical stimulation of rabbit skeletal muscle
increases growth of paired arteries and veins.
Adair, Thomas H., Jian Hang, Micheal L. Wells, Frenchye D. Magee, and
Jean-Pierre Montani.
Department of Physiology & Biophysics, University of Mississippi
Medical Center, Jackson, Mississippi 39216-4505
APStracts 2:0098H, 1995.
We tested whether chronic stimulation of skeletal muscle can increase
the growth of paired arteries and veins in rabbit extensor digitorum
longus muscle (EDL). The right EDL of female New Zealand white
rabbits was stimulated via the common peroneal nerve at 10 Hz using
300 msec square waves at 3-4 volts. Two hr periods of stimulation
were alternated with 4 hr periods of rest, 7 days per week for 60
days. The left EDL served as control. The hindlimb vascular system
was maximally dilated and perfuse-fixed with 3% glutaraldehyde and 2%
paraformaldehyde at arterial and venous pressures of 80-100 and 15-20
mm Hg, respectively. Muscles were post-fixed in OsO4 and embedded in
EPOX 812 resin. One mm-thick transverse sections were cut at uniform
locations through the entire breadth of the muscle and analyzed using
videomicroscopy along with computerized morphometric and
stereological techniques. All paired arteries and veins on each full
muscle section were analyzed. Chronic muscle stimulation caused the
wall volume of paired arteries and veins to increase by an average of
2-fold and the lumen volume to increase by an average of 3-fold,
compared to the contralateral control muscles. The wall-to-lumen area
ratio of the arteries and veins was not affected. Muscle stimulation
also caused the numerical density of arteries having a diameter
greater than 100 mm to increase by 4-fold, and the density of veins
having a perimeter greater than 500 mm to increase by 10-fold. The
length of paired arteries and veins increased by an average of 2-fold
during the 60 days of stimulation, but the tortuosity of the arteries
did not increase. Increased length in the absence of increased
tortuosity indicates that new artery-vein pairs were formed. The
results therefore support the hypothesis that long-term stimulation
of skeletal muscle causes a structurally based increase in diameter
along with proportionate growth of the media and the formation of
entirely new artery-vein pairs.
Received 7 September 1994; accepted in final form 8 March 1995.
APS Manuscript Number H805-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 March 1995.