Key result
Aortic banding in rats alters cardiac noradrenaline turnover and consistently decreases uptake.
Why the study?
The function of the sympathetic system soon after increased pressure overload on the heart was not well characterized.
Does aortic banding alter noradrenaline turnover and metabolism in the myocardium of rats?
Does aortic banding alter noradrenaline turnover and metabolism in the myocardium of rats?
Aortic banding in rats induces early, time-dependent alterations in myocardial noradrenaline turnover and metabolism that accompany the development of cardiac hypertrophy.
Should not yet change clinical practice; hypothesis-generating for noradrenaline dynamics in pressure-overload hypertrophy models.
STUDY OBJECTIVE: The aim was to provide meaningful information on the function of the sympathetic system soon after an increased pressure overload on the heart. DESIGN: Noradrenaline storage, turnover, uptake, and synthesis were investigated at 3, 14, and 28 d after aortic banding in rats. Sham operated rats without aortic banding were used as control group. EXPERIMENTAL MATERIAL: Left ventricle, spleen, and kidney from male Sprague-Dawley rats (175-200 g) were used in this study. MEASUREMENTS AND MAIN RESULTS: Cardiac noradrenaline concentration was decreased at 3 d and 28 d after banding and increased at 14 d; left ventricular mass was increased from 14 d onwards. The rate of change in the specific activity of myocardial noradrenaline (noradrenaline turnover) as well as dopamine beta hydroxylase, an enzyme for noradrenaline synthesis, was unaltered at 3 d, increased at 14 d, and decreased at 28 d after aortic banding. Myocardial [3H]noradrenaline uptake, on the other hand, was decreased at all time points studied. The changes observed in the myocardium at day 14 were specific since noradrenaline turnover rate was unaltered in other peripheral organs such as spleen and kidney. Furthermore, after ganglionic blockade with pentolinium, both sham operated control and banded animals had identical, low noradrenaline turnover rate constants, and significant restoration of cardiac weight and noradrenaline stores was observed in the hearts from banded animals. CONCLUSIONS: Noradrenaline turnover and metabolism are altered soon after imposing increased workload on heart. Whether or not the changes in the sympathetic activity are a prerequisites for hypertrophy still remains to be seen.
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Ganguly et al. (1991) studied Increased pressure overload on the heart. Aortic banding vs. Sham operation was evaluated on Cardiac noradrenaline concentration, turnover, uptake, and synthesis. Aortic banding in rats altered cardiac noradrenaline turnover and metabolism, with decreased concentration at 3 and 28 days and increased at 14 days, alongside decreased uptake at all time points.