Repository of Research and Investigative Information

Repository of Research and Investigative Information

Shahid Sadoughi University of Medical Sciences

ENDOTOXEMIA IS ASSOCIATED WITH PARTIAL UNCOUPLING OF CARDIAC PACEMAKER FROM CHOLINERGIC NEURAL CONTROL IN RATS

(2012) ENDOTOXEMIA IS ASSOCIATED WITH PARTIAL UNCOUPLING OF CARDIAC PACEMAKER FROM CHOLINERGIC NEURAL CONTROL IN RATS. Shock. pp. 219-227. ISSN 1073-2322

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Abstract

Cardiac cycle is regulated by a complex interplay between autonomic nervous system and cardiac pacemaker cells. Decreased heart rate variability (HRV) and increased cardiac rhythm regularity are associated with poor prognosis in patients with systemic inflammation (e. g., sepsis). However, the underlying mechanism of decreased HRV in systemic inflammation is not understood. It is known that greater regularity in a complex system could indicate uncoupling of the system's components. The present study aimed to test the hypothesis that impaired responsiveness of cardiac pacemaker to autonomic nervous system may lead to uncoupling of the cardiovascular regulatory mechanisms during systemic inflammation. Systemic inflammation was induced by intraperitoneal injection of endotoxin (lipopolysaccharide, 1 mg/kg) in rats. Cardiovascular signals were recorded in conscious animals using a telemetric system. Heart rate dynamics was analyzed using Poincare plot, and cardiac cycle regularity was assessed by sample entropy analysis. Spontaneously beating atria were isolated, and chronotropic responsiveness to adrenergic and cholinergic stimulation was assessed using standard organ bath. Sample entropy decreased significantly 4 h after endotoxin injection in conscious rats. Vagal modulation of cardiac cycle (as assessed by Poincare plot) also exhibited a significant reduction in endotoxemic rats. Acute endotoxin challenge was associated with a significant hyporesponsiveness of isolated spontaneously beating atria to cholinergic stimulation. The chronotropic responsiveness to adrenergic stimulation was identical in controls and endotoxin-treated rats. These data propose that systemic inflammation is linked to reduced cardiac responsiveness to cholinergic stimulation. This may lead to partial uncoupling of cardiac pacemaker cells from autonomic neural control and can explain decreased HRV during systemic inflammation.

Item Type: Article
Keywords: Endotoxin heart rate variability sample entropy systemic inflammation heart-rate-variability septic shock atrial-fibrillation sample entropy time-series onset mice irregularity activation regularity General & Internal Medicine Hematology Surgery Cardiovascular System & Cardiology
Page Range: pp. 219-227
Journal or Publication Title: Shock
Journal Index: WoS
Volume: 37
Number: 2
Identification Number: https://doi.org/10.1097/SHK.0b013e318240b4be
ISSN: 1073-2322
Depositing User: Mr mahdi sharifi
URI: http://eprints.ssu.ac.ir/id/eprint/30377

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