Differential β-adrenoceptor expression induced by nerve growth factor infusion into the canine right and left stellate ganglia

Abstract

Background: Nerve growth factor (NGF) infusion into the right stellate ganglion (RSG) is antiarrhythmic, while NGF infusion into the left stellate ganglion (LSG) is proarrhythmic in dogs with myocardial infarction (MI) and complete atrioventricular block (CAVB). This functional asymmetry suggests differential neural remodeling. Objectives: To test the hypothesis that NGF infusion into the RSG and the LSG can lead to differential β-adrenoceptor (β-AR) expression in dogs with MI and CAVB. Methods and results: We performed immunostaining to quantify β1-AR and β3-AR immunoreactivity in six dogs with MI and CAVB, nine dogs with MI, CAVB, and NGF infusion to the LSG, six dogs with MI, CAVB, and NGF infusion to the RSG, and six normal dogs. There was significantly increased β3-AR immunoreactivity in dogs with NGF infusion into the LSG and significantly decreased β3-AR immunoreactivity in dogs with NGF infusion into the RSG compared with controls and with the MI and CAVB group. There were no significant differences in β1-AR immunoreactivity among these four groups. To determine protein and mRNA expression of β-ARs, we created MI and CAVB and infused NGF into the LSG in six additional dogs. The noninfarcted left ventricle free wall was harvested 1 week later. The protein level and receptor density of β3-AR (but not β1- or β2-AR) significantly increased in these six dogs compared with normal controls. Conclusions: We conclude that NGF infusion into the RSG and the LSG in dogs with MI and CAVB induced differential β3-AR expression in the left ventricular myocardium. © 2005 Heart Rhythm Society. All rights reserved.