Study on renal sympathetic denervation to modulate the nocturnal sympathetic tone in rats with myocardial infarction

An increase in renal sympathetic nerve activity plays a role in the development of heart failure (HF), but effects of renal sympathetic denervation (RD) on circadian sympathetic tone remains unclear in HF. We studied whether long-term RD could modify circadian changes in sympathoexcitation in rats with HF due to myocardial infarction (MI). Methods: Rats underwent bilateral RD and surgically induced MI. Blood pressure (BP), heart rate and locomotor activity were continuously recorded in conscious rats, by using instrumented radiotelemetry pressure transducer. Sympathetic nerve activity was assessed by low-frequency components (0.15-0.79Hz) of diastolic BP variability. Results: A transient sympathoexcitation was observed during the awaking period. In rats with MI and RD, sympathetic tone during the awaking period was decreased when compared with MI rats without RD (p<0.05). Conclusions: These data suggest that long-term RD could modify circadian sympathetic tone in rats with MI.