Altered nitric oxide mechanism within the paraventricular nucleus contributes to the augmented carotid body chemoreflex in heart failure
- 1 January 2007
- journal article
- Published by American Physiological Society in American Journal of Physiology-Heart and Circulatory Physiology
- Vol. 292 (1), H149-H157
- https://doi.org/10.1152/ajpheart.00117.2006
Abstract
Our previous study demonstrated a contribution of the paraventricular nucleus (PVN) of the hypothalamus in the processing of the carotid body (CB) chemoreflex. Nitric oxide (NO) (within the PVN), known to modulate autonomic function, is altered in rats with heart failure (HF). Therefore, the goal of the present study was to examine the influence of endogenous and exogenous NO within the PVN on the sympathoexcitatory component of the peripheral chemoreflex in normal and HF states. We measured mean arterial blood pressure, heart rate, renal sympathetic nerve activity (RSNA), and phrenic nerve activity (PNA) in sham-operated and HF rats (6–8 wk after coronary artery ligation) after incremental doses of potassium cyanide (25–100 μg/kg iv). There was potentiation of the reflex responses in HF compared with sham-operated rats. Bilateral microinjection of an inhibitor of NO synthase, N G-monomethyl-l-arginine (50 pmol), into the PVN augmented the RSNA and PNA response to peripheral chemoreceptor stimulation in sham-operated rats but had no effect in HF rats. Conversely, bilateral microinjection of a NO donor, sodium nitroprusside (50 nmol), into the PVN attenuated the RSNA response of the peripheral chemoreflex in sham-operated rats but to a smaller extent in HF rats. These data indicate that 1 ) NO within the PVN plays an important role in the processing of the CB chemoreflex and 2 ) there is an impairment of the NO function within the PVN of HF rats, which contributes to an augmented peripheral chemoreflex and subsequent elevation of sympathetic activity in HF.Keywords
This publication has 35 references indexed in Scilit:
- Differential role of the paraventricular nucleus of the hypothalamus in modulating the sympathoexcitatory component of peripheral and central chemoreflexesAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2005
- Exercise training improves endogenous nitric oxide mechanisms within the paraventricular nucleus in rats with heart failureAmerican Journal of Physiology-Heart and Circulatory Physiology, 2005
- Effects of nNOS antisense in the paraventricular nucleus on blood pressure and heart rate in rats with heart failureAmerican Journal of Physiology-Heart and Circulatory Physiology, 2005
- ANG II in the paraventricular nucleus potentiates the cardiac sympathetic afferent reflex in rats with heart failureJournal of Applied Physiology, 2004
- Paraventricular nucleus of the hypothalamus and elevated sympathetic activity in heart failure: the altered inhibitory mechanismsActa Physiologica Scandinavica, 2002
- NMDA and Kainate‐evoked Release of Nitric Oxide and Classical Transmitters in the Rat Striatum: In Vivo Evidence that Nitric Oxide May Play a Neuroprotective RoleEuropean Journal of Neuroscience, 1996
- Potentiation of sympathetic nerve responses to hypoxia in borderline hypertensive subjects.Hypertension, 1988
- Carotid chemoreceptor discharge responses to hypoxia and hypercapnia in normotensive and spontaneously hypertensive ratsJournal of the Autonomic Nervous System, 1987
- Hypothalamic Integration: Organization of the Paraventricular and Supraoptic NucleiAnnual Review of Neuroscience, 1983
- Paraventricular Nucleus:A Site for the Integration of Neuroendocrine and Autonomic MechanismsNeuroendocrinology, 1980