Abstract
Introduction:
Hypertension is a global burden. Renal denervation has been touted as a possible therapeutic strategy for the treatment of hypertension. However, neuromodulation of the renal nerves’ traffic in hypertension has yet to receive a similar attention.
Aim:
This study investigated cardio-respiratory responses to renal nerve stimulation in a genetic model of hypertension, the spontaneously hypertensive rat (SHR).
Methods:
In pentobarbital-anesthetized male SHRs (n = 9), the left renal nerve was stimulated 5 times (5-6 minutes apart) at 5 Hz, 0.5 ms, 0.5 mA for 30s. Mean arterial pressure (MAP), heart rate (HR), left renal cortical blood flow (CBF) and cortical vascular resistance (CVR), hindquarter aortic blood flow (ABF) and vascular resistance (AVR), upper (UAP) and lower (LAP) airway pressure, airway flow (AF), airway resistance (AR), respiration rate (RR) and diaphragmatic EMG (dEMG) were measured and averaged.
Results:
Cardiovascular responses to renal nerve stimulation were characterized by reductions in MAP, HR, CBF and AVR, which were associated with increases in ABF and CVR. Respiratory responses to renal nerve stimulation, on the other hand, demonstrated increases in AF, RR and dEMG, decreases in AR and no change in UAP and LAP.
Conclusions:
Under hypertensive conditions, the renal nerves not only modulate cardiovascular function but also improve respiratory function. These studies suggest that neuromodulation of the renal nerves may offer a therapeutic alternative for hypertensive patients.