Published in:
01-04-2010 | Original Article
Alterations of pre- and postsynaptic noradrenergic signaling in a rat model of adriamycin-induced cardiotoxicity
Authors:
Miran Kenk, BSc, James T. Thackeray, BSc, MSc, Stephanie L. Thorn, BSc, MSc, Karan Dhami, BSc, MD, Benjamin J. Chow, MD, FRCPC, FACC, FASNC, Kathy J. Ascah, MD, FRCPC, Jean N. DaSilva, PhD, Rob S. Beanlands, MD, FRCPC, FACC
Published in:
Journal of Nuclear Cardiology
|
Issue 2/2010
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Abstract
Background
Altered sympathetic nervous system signaling is known to play a role in the cardiotoxicity of the anthracycline chemotherapeutic agents, but the interaction of pre- and postsynaptic function is not well understood.
Methods and Results
Our aim was to study the noradrenergic signaling in an established rat model of adriamycin cardiotoxicity (15 mg/kg administered i.p. over 2 weeks) using radiotracers having potential applicability for imaging with positron emission tomography (PET). Ex vivo biodistribution was performed 1 and 3 weeks post-adriamycin treatment with the noradrenaline analogue [11C]meta-hydroxyephedrine ([11C]HED), β-adrenergic receptor antagonist [3H]CGP12177, and phosphodiesterase-4 inhibitor (R)-[11C]rolipram. Cardiac function (echocardiographic parameters) and heart/body weight ratio were not affected. Myocardial retention of [11C]HED, [3H]CGP12177, and (R)-[11C]rolipram were unchanged 1 week post-adriamycin. Compared to controls, 3 weeks post-treatment [3H]CGP12177 uptake decreased (left ventricle free wall and septum; P < 0.05), while [11C]HED and (R)-[11C]rolipram uptake were unaffected. Following acute increase in myocardial noradrenaline levels with desipramine treatment, (R)-[11C]rolipram retention increased in the left atrium, right ventricle, left ventricle free wall and septum (P < 0.05) in vehicle-, but not adriamycin-treated animals.
Conclusion
Our results suggest that adriamycin-induced toxicity exhibits no change in presynaptic noradrenaline uptake, but decreased β-adrenergic receptors in cardiac tissues, supporting a role for PET imaging of noradrenaline signaling in the study of anthracycline cardiotoxicity.