Exercise training in 2K-1C hypertensive rats decreased arterial pressure, likely due to lower ANG II and higher nitritergic tone rather than enhanced GABA inhibition.
Does exercise training decrease mean arterial pressure and renal sympathetic nerve activity in two-kidney, one-clip hypertensive rats via enhanced nitric oxide or GABA signaling within the paraventricular nucleus?
Exercise training lowers blood pressure in renovascular hypertensive rats likely by diminishing excitatory inputs to the paraventricular nucleus due to lower angiotensin II and higher nitritergic tone.
Exercise-induced changes in γ-aminobutyric acid (GABA) or nitric oxide signaling within the paraventricular nucleus (PVN) have not been studied in renovascular hypertension. We tested whether exercise training decreases mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in two-kidney, one-clip (2K-1C) hypertensive rats due to enhanced nitric oxide or GABA signaling within PVN. Conscious, unrestrained male Sprague-Dawley rats with either sham (Sham) or right renal artery clipping (2K-1C) were assigned to sedentary (SED) or voluntary wheel running (ExT) for 6 or 12 wk. MAP and angiotensin II (ANG II) were elevated in 2K-1C SED rats. The 2K-1C ExT rats displayed lower MAP at 6 wk that did not decline further by 12 wk. Plasma ANG II was lower in 2K-1C ExT rats. Increases in MAP, heart rate, and RSNA to blockade of PVN nitric oxide in 2K-1C SED rats were attenuated compared with either Sham group. Exercise training restored the responses in 2K-1C ExT rats. The increase in MAP in response to bicuculline was inversely correlated with baseline MAP. The rise in MAP was lower in 2K-1C SED vs. either Sham group and was normalized in the 2K-1C ExT rats. Paradoxically, heart rate and RSNA responses were not diminished in 2K-1C SED rats but were significantly lower in the 2K-1C ExT rats. Thus the decrease in arterial pressure in 2K-1C hypertension associated with exercise training is likely due to diminished excitatory inputs to PVN because of lower ANG II and higher nitritergic tone rather than enhanced GABA inhibition of sympathetic output.
Rossi et al. (Wed,) conducted a other in Renovascular hypertension. Voluntary wheel running vs. Sedentary was evaluated on Mean arterial pressure and renal sympathetic nerve activity. Exercise training in 2K-1C hypertensive rats decreased arterial pressure, likely due to lower ANG II and higher nitritergic tone rather than enhanced GABA inhibition.