Format

Send to

Choose Destination
Am J Physiol Regul Integr Comp Physiol. 2016 Mar 1;310(5):R414-21. doi: 10.1152/ajpregu.00252.2015. Epub 2015 Dec 9.

Central vs. peripheral neuraxial sympathetic control of porcine ventricular electrophysiology.

Author information

1
Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles (UCLA) Health System, Los Angeles, California;
2
Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles (UCLA) Health System, Los Angeles, California; Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
3
Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA Health System, Los Angeles, California; and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA Health System, Los Angeles, California.
4
Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles (UCLA) Health System, Los Angeles, California; Cardiac Arrhythmia Center, David Geffen School of Medicine, UCLA Health System, Los Angeles, California; and Neurocardiology Research Center of Excellence, David Geffen School of Medicine, UCLA Health System, Los Angeles, California AMahajan@mednet.ucla.edu.

Abstract

Sympathoexcitation is associated with ventricular arrhythmogenesis. The aim of this study was to determine the role of thoracic dorsal root afferent neural inputs to the spinal cord in modulating ventricular sympathetic control of normal heart electrophysiology. We hypothesize that dorsal root afferent input tonically modulates basal and evoked efferent sympathetic control of the heart. A 56-electrode sock placed on the epicardial ventricle in anesthetized Yorkshire pigs (n = 17) recorded electrophysiological function, as well as activation recovery interval (ARI) and dispersion in ARI, at baseline conditions and during stellate ganglion electrical stimulation. Measures were compared between intact states and sequential unilateral T1-T4 dorsal root transection (DRTx), ipsilateral ventral root transection (VRTx), and contralateral dorsal and ventral root transections (DVRTx). Left or right DRTx decreased global basal ARI [Lt.DRTx: 369 ± 12 to 319 ± 13 ms (P < 0.01) and Rt.DRTx: 388 ± 19 to 356 ± 15 ms (P < 0.01)]. Subsequent unilateral VRTx followed by contralateral DRx+VRTx induced no further change. In intact states, left and right stellate ganglion stimulation shortened ARIs (6 ± 2% vs. 17 ± 3%), while increasing dispersion (+139% vs. +88%). There was no difference in magnitude of ARI or dispersion change with stellate stimulation following spinal root transections. Interruption of thoracic spinal afferent signaling results in enhanced basal cardiac sympathoexcitability without diminishing the sympathetic response to stellate ganglion stimulation. This suggests spinal dorsal root transection releases spinal cord-mediated tonic inhibitory control of efferent sympathetic tone, while maintaining intrathoracic cardiocentric neural networks.

KEYWORDS:

cardiac neuronal hierarchy; spinal cord; stellate ganglion; sympathetic nervous system; ventricular excitability

PMID:
26661096
PMCID:
PMC4796738
[Available on 2017-03-01]
DOI:
10.1152/ajpregu.00252.2015
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Atypon Icon for PubMed Central
Loading ...
Support Center