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

2016 ◽  
Vol 310 (5) ◽  
pp. R414-R421 ◽  
Author(s):  
Kentaro Yamakawa ◽  
Kimberly Howard-Quijano ◽  
Wei Zhou ◽  
Pradeep Rajendran ◽  
Daigo Yagishita ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Stellate Ganglion ◽  
Afferent Input ◽  
Ventral Root ◽  
Spinal Root ◽  
Sympathetic Control ◽  
Thoracic Spinal ◽  
Yorkshire Pigs ◽  
Heart Electrophysiology

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.

Abstract 036: The Role Of Spinal Modulation On The Ventricular Electrophysiology In A Porcine Model

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Wei Zhou ◽  
Kentaro Yamakawa ◽  
Olujimi Ajijola ◽  
Daigo Yagishita ◽  
Mariko Takemoto ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Ventricular Arrhythmias ◽  
Stellate Ganglion ◽  
Afferent Pathways ◽  
Beneficial Effects ◽  
Thoracic Epidural ◽  
Yorkshire Pigs ◽  
Efferent Pathways ◽  
Intact Roots

Background: Enhanced cardiac sympathetic tone has been associated with ventricular arrhythmias and sudden cardiac death. The spinal cord is an important integrative region of afferent and efferent pathways that participate in cardiovascular regulation. The purpose of this study is to investigate the role of spinal processing of cardiac afferent information on ventricular electrophysiology during cardiac sympathoexcitation. Methods: Female Yorkshire pigs (n=5) underwent surgical exposure of the heart and left stellate ganglion (LSG) through thoractomy as well as the dorsal and ventral roots of the spinal cord through laminectomy. A 56-electrode sock was placed over the ventricles to record epicardial electrograms. Animals underwent LSG stimulation in intact, after dorsal root transaction (DRTx), and followed by ventral root transaction (DVRTx). Activation recovery intervals (ARIs) were measured at each electrode before and during LSG stimulation. Results: With intact roots LSG stimulation resulted in significant global ARI shortening by 12.9% (p<0.05). After DRTx, mean global ARI shortened by 7.2%. LSG stimulation after DRTx and DVRTx resulted in greater ARI shortening compared to LSG stimulation with intact roots (21.5 and 18.4 vs 12.9%, p<0.05, see figure 1 below). ARI shortened more during LSG stimulation after DRTx than that after DVRTx (21.5 vs. 18.4%, p<0.05). Conclusion: Spinal afferent pathways play an inhibitory role in sympathoexcitation of ventricle induced by LSG stimulation. This finding provides insight into the mechanism underlying the beneficial effects of thoracic epidural anesthesia in reducing ventricular arrhythmias.

Responses of T2-4 spinal cord neurons to irritation of the lower airways in the rat

1997 ◽  
Vol 273 (3) ◽  
pp. R1147-R1157 ◽  
Author(s):  
T. Hummel ◽  
J. N. Sengupta ◽  
S. T. Meller ◽  
G. F. Gebhart
Keyword(s):  
Spinal Cord ◽  
Afferent Input ◽  
Sprague Dawley ◽  
Spinal Neurons ◽  
Thoracic Spinal Cord ◽  
Spinal Cord Neurons ◽  
Thoracic Spinal ◽  
Balloon Distension ◽  
Sprague Dawley Rats ◽  
Lower Airways

The aim of the study was to investigate the information processing in the thoracic spinal cord (T2-4) after chemical irritation of the lower airways. Experiments were performed in pentobarbital sodium-anesthetized and pancuronium-paralyzed male Sprague-Dawley rats. Balloon distension of the esophagus was used as the search stimulus. Ammonia and smoke were applied by means of a tracheal cannula; they produced excitatory, inhibitory, and biphasic responses in a concentration-related manner (ammonia 39/39; smoke 23/ 39). Inhaled irritant-responsive neurons exhibited a number of similarities that have been described for neurons responding to stimulation of other thoracic viscera. These similarities relate to the distribution of neurons in the deeper laminae of the thoracic spinal cord, the relatively small number of neurons receiving input from the lower airways, the extensive convergent input from the skin and other thoracic viscera, and the pattern of responses. In addition, both stimulus-induced responses and spontaneous activity are subject to modulation from supraspinal sites. On the basis of responses to inhaled irritants after either spinal cord or vagus nerve block/transection, these T2-4 spinal neurons are likely to receive spinal afferent input that is modulated by vagal-brain stem input.

scholarly journals Dorsal root ganglion stimulation for treatment of complex regional pain syndrome of the foot

2020 ◽  
Vol 3 (2) ◽  
pp. V8
Author(s):  
Kevin Hines ◽  
Fadi Al Saiegh ◽  
Aria Mahtabfar ◽  
Kavantissa M. Keppetipola ◽  
Caio M. Matias ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Root Ganglion ◽  
Complex Regional Pain Syndrome ◽  
Spinal Cord Stimulation ◽  
Dorsal Root ◽  
Pain Syndrome ◽  
Thoracic Spinal Cord ◽  
Plantar Aspect ◽  
Thoracic Spinal ◽  
The Right

This is a case of a 54-year-old man presenting with complex regional pain syndrome (CRPS) type 1 of the right lower extremity, which was most debilitating in the plantar aspect of the right foot. The patient had prior treatment with thoracic spinal cord stimulation; however, the foot pain remained intractable. Given that his pain was predominantly in his foot and remained debilitating despite thoracic spinal cord stimulation, it was recommended that the patient undergo a trial of dorsal root ganglion (DRG) stimulation. The surgical technique for placement of dorsal root ganglion stimulators is demonstrated in this operative video.The video can be found here: https://youtu.be/_1xMxFZa6tU

Selective cephalic upregulation of p-ERK, CamKII and p-CREB in response to glyceryl trinitrate infusion

Cephalalgia ◽  
2017 ◽  
Vol 38 (6) ◽  
pp. 1057-1070 ◽  
Author(s):  
Roshni Ramachandran ◽  
Sara Hougaard Pedersen ◽  
Dipak Vasantrao Amrutkar ◽  
Steffen Petersen ◽  
Julie Mie Jacobsen ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Root Ganglion ◽  
Dorsal Horn ◽  
Trigeminal Ganglion ◽  
Dura Mater ◽  
Dorsal Root ◽  
Spinal Cord Dorsal Horn ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Extracellular Signal

Background A common characteristic of migraine-inducing substances is that they cause headache and no pain in other areas of the body. Few studies have compared pain mechanisms in the trigeminal and spinal systems and, so far, no major differences have been noted. We compared signalling molecules in the trigeminal and spinothalamic system after infusion of the migraine-provoking substance glyceryltrinitrate. Method A catheter was placed in the femoral vein of rats and one week later glyceryltrinitrate 4 µg/kg/min was infused for 20 min. Protein expression in the dura mater, trigeminal ganglion, nucleus caudalis, dorsal root ganglion and the dorsal horn of the thoracic spinal cord was analysed at different time points using western blotting and immunohistochemistry. Results Glyceryltrinitrate caused a threefold increase in expression of phosphorylated extracellular signal-regulated kinases at 30 min in the dura mater and nucleus caudalis ( P < 0.05) and at 2 h in the trigeminal ganglion with very few expressions in the dorsal root ganglion. In the nucleus caudalis, expression of phosphorylated extracellular signal-regulated kinases and Cam KII increased 2.6-fold and 3.2-fold, respectively, at 2 h after glycerytrinitrate infusion ( P < 0.01). p-CREB/ATF-1 upregulation was observed only at 30 min ( P < 0.05) in the nucleus caudalis. None of these markers showed increased expression in the regions of thoracic spinal cord dorsal horn. Conclusion The dura, trigeminal ganglion and nucleus caudalis are activated shortly after glycerytrinitrate infusion with long-lasting expression of phosphorylated extracellular signal-regulated kinases observed in the nucleus caudalis. These activations were not observed at the spinal level.

Clinical study of reconstructed bladder innervation below the level of spinal cord injury to produce urination by Achilles tendon–to-bladder reflex contractions

2009 ◽  
Vol 10 (5) ◽  
pp. 452-457 ◽  
Author(s):  
Haodong Lin ◽  
Chunlin Hou ◽  
Xianyou Zhen ◽  
Zhen Xu
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Achilles Tendon ◽  
Neurogenic Bladder ◽  
External Sphincter ◽  
Ventral Root ◽  
Clinical Approach ◽  
Spinal Root ◽  
Cord Injury

Object Neurogenic bladder dysfunction following spinal cord injury (SCI) is a major medical and social problem for which there is no ideal treatment strategy. In the present study, the authors analyze the effectiveness of neurogenic bladder reinnervation in patients with SCIs by using Achilles tendon reflexes below the paraplegic level. Methods Spinal root anastomoses were performed in 12 paraplegic patients with hyperreflexic neurogenic bladder and detrusor external sphincter dyssynergia (DESD) caused by complete suprasacral SCI, in an attempt to reinnervate the bladder. The surgery anastomosed the unilateral proximal end of the S-1 ventral root and the distal end of the S-2 and/or S-3 ventral roots to build the Achilles tendon–to-bladder reflex, while the S-1 dorsal root was kept intact as the trigger for micturition after axonal regeneration. All patients underwent urodynamic evaluation before surgery and at follow-up. Results The mean follow-up duration was 3 years. Of the 12 patients, 9 (75%) regained satisfactory bladder control within 6 to 12 months after ventral root microanastomosis. In these 9 patients, urodynamic studies revealed a change from detrusor hyperreflexia with DESD and high detrusor pressure to almost normal storage and synergic voiding without DESD. The average bladder capacity increased from 258 ± 33 ml to 350 ± 49 ml, residual urine decreased from 214 ± 36 ml to 45 ± 11 ml, and urinary infections were not observed. Patients with impaired renal function experienced a full recovery. Three patients failed to show any improvement after the operation. Conclusions These results suggest the effectiveness of bladder innervation below the level of SCI to produce urination by Achilles tendon–to-bladder reflex contractions, and might therefore provide a new clinical approach to reconstructing spasmodic bladder urination function.

scholarly journals ON THE EXISTENCE OF A GRADIENT OF SENSITIVITY TO THE LACK OF SODIUM IN THE SPINAL ROOTS OF THE BULLFROG

1951 ◽  
Vol 35 (2) ◽  
pp. 183-201 ◽  
Author(s):  
R. Lorente de Nó
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Nerve Fibers ◽  
Nerve Trunk ◽  
Ventral Root ◽  
Gradual Change ◽  
Anatomical Distribution ◽  
Working Hypothesis ◽  
Temporal Course ◽  
Spinal Roots

The Et class of fibers includes fibers of Gasser's d.r. C group. The fibers of the dorsal root are more sensitive to the effect of lack of sodium than are the fibers of the ventral root. In the two roots there is a gradient of sensitivity to the lack of sodium, which is such that in all the root fibers the sensitivity decreases with increasing distance from the spinal cord. The gradient continues in the trunk up to about 10 to 12 mm. peripheral to the trunk-roots margin. No comparable gradient of sensitivity to the lack of sodium has been observed in the rest of the nerve trunk. The gradient of sensitivity to the lack of sodium has no relationship to the anatomical distribution of the epineurium. As a working hypothesis it is suggested that the gradient of sensitivity to the lack of sodium is one aspect of a transitional gradient that serves to establish a gradual change between the properties that the axons have inside the spinal cord and the properties that they have inside the nerve trunks. Details are given of the temporal course of the loss of excitability by root fibers deprived of sodium. It is suggested that sodium is present in the nerve fibers, in 2 forms, loosely and tightly bound sodium and that loss of loosely bound sodium is sufficient to render the nerve fibers unable to conduct impulses. If the rate of loss of loosely bound sodium is decreased, conversion of tightly bound into loosely bound sodium may temporarily restore the excitability of the nerve fibers.

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