Change of Vanilloid Receptor 1 Following Neuromodulation in Rats with Spinal Cord Injury

Zhou, Yuan; Wang, Yongjin; Abdelhady, Mazen; Mourad, Sherif; Hassouna, Magdy

doi:10.1006/jsre.2002.6481

Cited by 30 publications

(37 citation statements)

References 25 publications

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“…5,6 Our previous studies suggested that the greater density of descending serotonergic and noradrenergic projections, elicited by the neuroprotective effects of the cellular grafts transplanted into a contusion lesion site, ameliorates of the dyssynergia between the bladder and the urethral sphincter 2-4 by providing some descending control over spinal nuclei and greater descending control over sensory transmission in the DH. [9][10][11][12] The density of bladder afferent projections, that is, CGRP-positive fibers in the DH, is increased after severe SCI [13][14][15] and this has been implicated in detrusor overactivity that develops following SCI. [2][3][4] Bladder afferents in the lumbosacral spinal cord also project to the DH, SPN and dorsal commissure in the lumbosacral spinal cord, 16,17 which was induced by disruption of the descending projections.…”

Section: Normalmentioning

confidence: 99%

Lower urinary tract function in spinal cord-injured rats: midthoracic contusion versus transection

2014

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Objectives: To compare changes in lower urinary tract (LUT) function with modifications in pathways that regulate LUT function using two different animal models (incomplete and complete) of spinal cord injury (SCI). Methods: Female Sprague-Dawley rats were used. SCI was made at Th8/9 by a contusion injury (contusion, n ¼ 9) or a complete transection (transection, n ¼ 9). Unoperated rats were used as normal controls (normal, n ¼ 6). LUT function was evaluated by micturition behavior in metabolic cages for 24 h and cystometry in awake animals. Immunocytochemical staining at the L6 spinal cord, spinal areas associated with LUT, was performed to identify descending modulatory fibers and dorsal root afferents that project to the L6 spinal cord. Results: Volume/micturition in metabolic cages gradually increased in both contusion and transection groups compared with normals, and operated groups did not differ from each other. Urodynamic parameters from cystometry were significantly different in contusion and transection groups compared with normals, but again there was no significant difference between contusion and transection groups. Immunocytochemical analyses at the L6 spinal cord showed no serotonergic or noradrenergic fibers in transection group, but some descending fibers remained in contusion group, indicating sparing. Small dorsal root afferents were denser in both contusion and transection groups than in normals, indicating sprouting. Conclusions: Although differences were not found in LUT function in operated animals, supraspinal and dorsal root projections to the L6 spinal cord responded differently to contusion and transection. This suggests that the benefits of pharmacologic treatments may be different in two lesion models. Spinal Cord (2014) 52, 658-661; doi:10.1038/sc.2014.114; published online 15 July 2014 INTRODUCTION Spinal cord injury (SCI) is classified clinically into complete injuries,where function below the level of a injury is lost, and incomplete injuries where some sensory and/or motor function is retained. Nevertheless, it is known that some descending pathways are spared in many cases of clinically complete injuries. 1 Lower urinary tract (LUT) dysfunction in SCI results from damage to descending modulatory pathways and increased sensory input through sprouting of primary afferent pathways. A contusion injury that we use destroys the dorsal spinal cord in the thoracic region, including the dorsal columns, the corticospinal tract and the dorsolateral (DL) funiculus, damages the dorsal horn (DH) and impinges on the intermediolateral column. 2-4 Thus, the ventral funiculi and the ventral portions of the lateral funiculi, which contain descending modulatory pathways, were partially spared in contusion injuries, but not in transection injuries.Serotonergic axons project to the DL nucleus in the spinal cord, which has been implicated in the central control of the bladder and the urethra and recovery of bladder-external urethral sphincter coordination in SCI rats. 5,6 Brainstem-spinal noradrenerg...

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Section: Normalmentioning

confidence: 99%

Lower urinary tract function in spinal cord-injured rats: midthoracic contusion versus transection

2014

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“…Other receptors (ie serotonin 2A, vanilloid VR1) also increase in density by 1-3 days caudal to spinal cord transection. 53,54 Such trans criptional/translational increases in neurotransmitter receptors could explain the initial re-emergence of reflexes. Receptor plasticity over 1-3 days post-SCI may underlie re-emergence of cutaneous reflexes in cats and humans, 7,55 tibial H-reflexes by 24 h in rats and humans, 28,33,34,56 and anal reflexes in rats and humans.…”

Section: Phase 2: Initial Reflex Return (1-3 Days)mentioning

confidence: 99%

“…138,139 Functional electrical stimulation is an alternative method for stimulating specific synapses and neuron pools, therefore influencing spinal cord plasticity and performance. [140][141][142] Additional interventions that might enhance synapse formation by spared descending inputs include medications to increase excitability of spinal neurons (eg 5-HTP, clonidine, TRH, and theophylline), 54,[143][144][145] stimulants of axon growth (eg inosine), 146 stimulants of NT synthesis (eg clenbuterol), 147,148 inhibitors of Nogo and related myelin glycoproteins that block longer-distance axon sprouting, 149 and agents that block the intracellular Rho pathway, which inhibits axon growth. 150 Adding these interventions in combination with exercise therapies might have a synergistic effect on activity-dependent synapse growth.…”

Section: Clinical Implications Of Spinal Shockmentioning

confidence: 99%

“…Is overshoot in spinal reflexes noted, as is expected if denervation supersensitivity overlaps with new synapse growth for several days, until supersensitivity wanes? 54,111 Does the latest phase of hyper-reflexia for the patellar tendon reflex (L3 afferent, L3 efferent) precede the latest phase of hyper-reflexia for the Achilles tendon reflex (S1 afferent, S1 efferent) given that the axon length is much less for patellar than Achilles reflex? Studies to address these questions will help refine the proposed model of spinal shock or may suggest an alternative model.…”

Section: Future Research On Spinal Shockmentioning

confidence: 99%

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Spinal shock revisited: a four-phase model

et al. 2004

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Spinal shock has been of interest to clinicians for over two centuries. Advances in our understanding of both the neurophysiology of the spinal cord and neuroplasticity following spinal cord injury have provided us with additional insight into the phenomena of spinal shock. In this review, we provide a historical background followed by a description of a novel fourphase model for understanding and describing spinal shock. Clinical implications of the model are discussed as well.

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“…14 In rodents, vanilloid receptor 1 (VR1) expression was upregulated in the dorsal horn of the spinal cord after spinal cord injury, and neuromodulation was also associated with reduced expression of VR1. 15 Using a chemical cystitis model of HCl and acetic acid, the same group reported that although sacral stimulation (S1) could reduce voiding frequency rates, there did not appear to be a difference in the number of c-fos-positive neurons in the L6 spinal cord. 16 However, because most patients undergoing implantation do not have spinal cord injury nor evidence of acute bladder inflammation, it is unclear whether the mechanisms described in these animal studies may be involved.…”

Section: Possible Mechanisms Of Action Of Neuromodulation For Voidingmentioning

confidence: 99%

Sacral Nerve Stimulation: Neuromodulation for Voiding Dysfunction and Pain

Mayer

Howard

2008

Neurotherapeutics

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Summary:Voiding dysfunction, which includes incontinence, retention, and chronic pelvic pain, is a relatively frequent problem that can be difficult to manage. Neuromodulation via stimulation of the sacral nerves has been shown to improve thesesymptoms, although the exact mechanisms remain elusive. Techniques for nerve stimulation may vary, depending on the disease, location of pain, and the patient's anatomy. In addition to placement of electrodes on the sacral nerve roots, modulation has also been reported by peripheral branches of the sacral nerves including the pudendal and posterior tibial nerves. Newer surgical techniques have significantly decreased the morbidity of the procedures and increased the probability of a successful outcome.

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Change of Vanilloid Receptor 1 Following Neuromodulation in Rats with Spinal Cord Injury

Cited by 30 publications

References 25 publications

Lower urinary tract function in spinal cord-injured rats: midthoracic contusion versus transection

Lower urinary tract function in spinal cord-injured rats: midthoracic contusion versus transection

Spinal shock revisited: a four-phase model

Sacral Nerve Stimulation: Neuromodulation for Voiding Dysfunction and Pain

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