The renin-angiotensin-aldosterone system excites hypothalamic paraventricular nucleus neurons in heart failure

1 Department of Internal Medicine and Cardiovascular Center, University of Iowa Iowa City 52242 and 2 Research Service, Department of Veterans Affairs Medical Center, Iowa City, Iowa 52246 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