Selective regulation of sympathetic presynaptic components in rat
left ventricle during long-term ligation of the abdominal aorta.
Nyquist-Battie, Cynthia, Pamela K. Cochran, Vincent R. Evans, James M.
Hitchcock, and Can Unal.
Division of Cell Biology and Biophysics, School of Biological
Sciences, University of Missouri-Kansas City, 2411 Holmes Street,
Kansas City, MO 64108-2792
APStracts 3:0167H, 1996.
To assess the effects of long-term pressure-overload on sympathetic
presynaptic components in the left ventricle, young adult male rats
were subjected to surgical constriction of the suprarenal abdominal
aorta. At weeks 4 and 8 post-surgery, but not at week 1, left
ventricular sympathetic activity, measured by the net fractional
norepinephrine (NE) decrease after [alpha]-methyl-tyrosine methyl
ester administration, was elevated in the aortic-banded rats.
However, left ventricular NE was reduced only at eight weeks.
Scatchard analysis of saturation binding of 3H- nisoxetine, a
specific ligand for NE uptake1 sites, determined that left
ventricular NE transporter sites were also reduced at eight weeks,
suggesting a relationship between a reduced number of uptake sites
and loss of NE stores. In contrast, aortic constriction did not
reduce neuropeptide Y, tyrosine hydroxylase, dopamine [beta]
hydroxylase, nerve growth factor and low-affinity nerve growth factor
receptors at any time point. Thus, long-term pressure-overload can
cause a selective reduction in ventricular NE stores without a
reduction in NPY, a co-localized sympathetic neurotransmitter.
Received 30 May 1995; accepted in final form 27 March 1996.
APS Manuscript Number H496-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 1 May 96