Regulation of sympathetic presynaptic components in rat left ventricle during ligation of abdominal aorta.
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 4 and 8 wk postsurgery, but not at 1 wk, left ventricular sympathetic activity, measured by the net fractional norepinephrine (NE) decrease after alpha-methyl-p-tyrosine methyl ester administration, was elevated in the aortic-banded rats. However, left ventricular NE was reduced only at 8 wk. Scatchard analysis of saturation binding of [3H]nisoxetine, a specific ligand for NE uptake sites, determined that left ventricular NE transporter sites were also reduced at 8 wk, suggesting a relationship between a reduced number of uptake sites and loss of NE stores. In contrast, aortic constriction did not reduce neuropeptide Y (NPY), tyrosine hydroxylase, dopamine beta-hydroxylase, nervegrowth 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 colocalized sympathetic neurotransmitter.
Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City 64108-2792, USA.
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Nyquist-Battie
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Cochran
V R
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Evans
J M
JM
Hitchcock
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C
Unal
D000818:Animals; D001012:Aorta, Abdominal; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism; D005473:Fluoxetine / Q000031:analogs & derivatives / Q000378:metabolism; D006973:Hypertension / Q000503:physiopathology*; D008026:Ligation; D008297:Male; D008781:Methyltyrosines / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism; D009478:Neuropeptide Y / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D050484:Norepinephrine Plasma Membrane Transport Proteins; D017729:Presynaptic Terminals / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D027981:Symporters; D013997:Time Factors; D016277:Ventricular Function, Left
D002352:Carrier Proteins; D008781:Methyltyrosines; D009478:Neuropeptide Y; D050484:Norepinephrine Plasma Membrane Transport Proteins; C493226:Slc6a2 protein, rat; D027981:Symporters; D005473:Fluoxetine; C011386:nisoxetine; C022260:alpha-methyltyrosine methyl ester; D009638:Norepinephrine