Ischemia-induced heart failure in rats increased PVN neuron firing rates compared to sham controls (8.7 vs 2.7 spikes/s, P<0.001), an effect significantly reduced by RAAS antagonists (P<0.05).
Do forebrain-directed intracarotid artery injections of RAAS inhibitors reduce PVN neuronal activity in rats with ischemia-induced heart failure?
The renin-angiotensin-aldosterone system drives PVN neuronal activity in heart failure, providing a mechanism for neurohumoral excitation that can be targeted by systemic therapies.
Absolute Event Rate: 8.7% vs 2.7%
p-value: p=<0.001
The paraventricular nucleus (PVN) of the hypothalamus has critical homeostatic functions, including the regulation of fluid balance and sympathetic drive. It has been suggested that altered activity of this nucleus contributes to the progression of congestive heart failure (HF). We hypothesized that forebrain influences of the renin-angiotensin-aldosterone system augment the activity of PVN neurons in HF. The rate of PVN neurons (n = 68) from rats with ischemia-induced HF was higher than that of PVN neurons (n = 42) from sham-operated controls (8.7 +/- 0.8 vs. 2.7 +/- 0.3 spikes/s, P < 0.001, HF vs. SHAM). Forebrain-directed intracarotid artery injections of the angiotensin type 1 receptor antagonist losartan, the angiotensin-converting enzyme inhibitor captopril, and the mineralocorticoid receptor antagonist spironolactone all significantly (P < 0.05) reduced PVN neuronal activity in HF rats. These findings demonstrate that the renin-angiotensin-aldosterone system drives PVN neuronal activity in HF, likely resulting in increased sympathetic drive and volume accumulation. This mechanism of neurohumoral excitation in HF is accessible to manipulation by blood-borne therapeutic agents.
Zhang et al. (Mon,) conducted a other in Heart failure. Intracarotid injections of losartan, captopril, and spironolactone vs. Sham-operated controls was evaluated on Rate of PVN neurons (spikes/s) (p=<0.001). Ischemia-induced heart failure in rats increased PVN neuron firing rates compared to sham controls (8.7 vs 2.7 spikes/s, P<0.001), an effect significantly reduced by RAAS antagonists (P<0.05).