title: Central vs. peripheral neuraxial sympathetic control of porcine ventricular electrophysiology.
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.
authors.affiliation: Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles (UCLA) Health System, Los Angeles, California;
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamakawa
authors.affiliation: 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.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Howard-Quijano
authors.affiliation: Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles (UCLA) Health System, Los Angeles, California;
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.affiliation: 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.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Rajendran
authors.affiliation: 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.
authors.forename: Daigo
authors.initials: D
authors.lastname: Yagishita
authors.affiliation: 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.
authors.forename: Marmar
authors.initials: M
authors.lastname: Vaseghi
authors.affiliation: 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.
authors.forename: Olujimi A
authors.initials: OA
authors.lastname: Ajijola
authors.affiliation: 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.
authors.forename: J Andrew
authors.initials: JA
authors.lastname: Armour
authors.affiliation: 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.
authors.forename: Kalyanam
authors.initials: K
authors.lastname: Shivkumar
authors.affiliation: 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.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Ardell
authors.affiliation: 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.
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
mesh_terms: D000200:Action Potentials; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology; D004558:Electric Stimulation; D005260:Female; D006339:Heart Rate; D006352:Heart Ventricles / Q000294:innervation*; D007796:Laminectomy; D008297:Male; D023421:Models, Animal; D009433:Neural Inhibition; D009475:Neurons, Afferent / Q000502:physiology; D009476:Neurons, Efferent / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology* / Q000601:surgery; D013126:Spinal Nerve Roots / Q000502:physiology* / Q000601:surgery; D013233:Stellate Ganglion / Q000502:physiology; D013552:Swine; D013564:Sympathetic Nervous System / Q000502:physiology*; D016277:Ventricular Function, Left; D017725:Ventricular Pressure
keywords: cardiac neuronal hierarchy; spinal cord; stellate ganglion; sympathetic nervous system; ventricular excitability