Enhanced angiotensin-mediated excitation of renal sympathetic nerve activity within the paraventricular nucleus of anesthetized rats with heart failure
Open Access
- 1 November 2009
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
- Vol. 297 (5), R1364-R1374
- https://doi.org/10.1152/ajpregu.00149.2009
Abstract
Chronic heart failure (HF) is characterized by increased sympathetic drive. Enhanced angiotensin II (ANG II) activity may contribute to the increased sympathoexcitation under HF condition. The present study examined sympathoexcitation by 1) the effects of ANG II in the paraventricular nucleus (PVN) on renal sympathetic nerve activity (RSNA), and 2) the altered ANG II type 1 (AT1) receptor expression during HF. Left coronary artery ligation was used to induce HF. In the anesthetized Sprague-Dawley rats, microinjection of ANG II (0.05–1 nmol) into the PVN increased RSNA, mean arterial pressure (MAP), and heart rate (HR) in both sham-operated and HF rats. The responses of RSNA and HR were significantly enhanced in rats with HF compared with sham rats (RSNA: 64 ± 8% vs. 33 ± 4%, P < 0.05). Microinjection of AT1 receptor antagonist losartan into the PVN produced a decrease of RSNA, MAP, and HR in both sham and HF rats. The RSNA and HR responses to losartan in HF rats were significantly greater (RSNA: −25 ± 4% vs. −13 ± 1%, P < 0.05). Using RT-PCR and Western blot analysis, we found that there were significant increases in the AT1 receptor mRNA (Δ186 ± 39%) and protein levels (Δ88 ± 20%) in the PVN of rats with HF ( P < 0.05). The immunofluorescence of AT1 receptors was significantly higher in the PVN of rats with HF. These data support the conclusion that an increased angiotensinergic activity on sympathetic regulation, due to the upregulation of ANG II AT1 receptors within the PVN, may contribute to the elevated sympathoexcitation that is observed during HF.Keywords
This publication has 57 references indexed in Scilit:
- Imbalance of Angiotensin Type 1 Receptor and Angiotensin II Type 2 Receptor in the Rostral Ventrolateral MedullaHypertension, 2008
- Cross-talk between cytokines and renin-angiotensin in hypothalamic paraventricular nucleus in heart failure: role of nuclear factor- BCardiovascular Research, 2008
- Chronic Baroreceptor Activation Enhances Survival in Dogs With Pacing-Induced Heart FailureHypertension, 2007
- Exercise Training Prevents Arterial Baroreflex Dysfunction in Rats Treated With Central Angiotensin IIHypertension, 2007
- Augmented Input From Cardiac Sympathetic Afferents Inhibits Baroreflex in Rats With Heart FailureHypertension, 2005
- Electrophysiological and morphological properties of pre‐autonomic neurones in the rat hypothalamic paraventricular nucleusThe Journal of Physiology, 2001
- NEUROHUMORAL ACTIVATION IN HEART FAILURE: ROLE OF PARAVENTRICULAR NUCLEUSClinical and Experimental Pharmacology and Physiology, 1996
- The Effect of Carvedilol on Morbidity and Mortality in Patients with Chronic Heart FailureNew England Journal of Medicine, 1996
- Parvocellular neurons of the paraventricular nucleus are involved in the reduction in renal nerve discharge during isotonic volume expansionJournal of the Autonomic Nervous System, 1994
- Angiotensin II exerts differential actions on renal nerve activity and heart rate.Hypertension, 1994