Restorative effect of atrial natriuretic peptide or chronic neutral endopeptidase inhibition on blunted cardiopulmonary vagal reflexes in aged rats

Hypertension
Colleen J ThomasR L Woods

Abstract

Arterial baroreflex function diminishes with age, but whether cardiopulmonary vagal reflexes are similarly altered with physiological aging has not been fully elucidated. In this study, predominantly cardiac high pressure mechanoreceptor-activated (ramp baroreflex) and cardiopulmonary chemoreceptor-activated (von Bezold-Jarisch reflex) vagal reflexes in conscious, instrumented rats were impaired by 30% to 40% (P<0.05) in 24-month-old (n=12) compared with 6-month-old rats (n=12). To determine whether this is a restorable deficit, the influence of atrial natriuretic peptide (ANP), either by infusion or blockade of its breakdown, was studied. ANP infusion was previously shown to enhance Bezold-Jarisch reflex and ramp baroreflex bradycardia in young adult rats. The present study confirmed that vagal reflex augmentation by ANP (50 pmol/kg per minute) also occurs in old rats (increased by 60+/-18% (Bezold-Jarisch reflex) and 91+/-15% (ramp baroreflex; P<0.05). Direct vagal stimulation in anesthetized animals showed that the target for ANP was not the cardiac vagus itself in old rats (n=7), although in young rats only, we confirmed the published finding that ANP enhances vagal bradycardia (by 58+/-14%, n=7). Neutral endopeptidase 24.1...Continue Reading

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Feb 8, 2003·Hypertension·Colleen J Thomas, Robyn L Woods
Nov 6, 2003·Journal of Applied Physiology·Alberto U FerrariMarco Centola

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Citations

Sep 4, 2012·Analytical and Bioanalytical Chemistry·Min-Jung KangByung-Hwa Jung
May 22, 2009·The Journal of Biological Chemistry·Deborah M DickeyLincoln R Potter
Nov 28, 2012·Nutrition Research·Denovan P BeggRichard S Weisinger
Jan 10, 2012·Neurobiology of Aging·Denovan P BeggRichard S Weisinger
Jul 3, 2016·Cardiovascular Research·Antonio CannatàFrancesco S Loffredo

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