Effect of spinal cord injury severity on alterations of the H-reflex

Lee, Jae K.; Emch, Gregory S.; Johnson, Christopher; Wrathall, Jean R.

doi:10.1016/j.expneurol.2005.08.018

Cited by 73 publications

(65 citation statements)

References 58 publications

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“…The contusion results in a central hemorrhagic lesion that spares a peripheral rim of white matter at the lesion epicenter and partially spares descending control fibers such as some of the serotonergic fibers from the brainstem to the plantar motor neurons, as illustrated in our initial report examining H-reflex alterations (Lee et al, 2005). For transections, irridectomy scissors were used to completely sever the spinal cord at T8, and gel foam was placed into the lesion site.…”

Section: Spinal Cord Injury and Animal Carementioning

confidence: 99%

“…The mechanism for this elevated reflex is still unclear. Our previous study demonstrated that the increased H-reflex amplitude observed at 4wks after different severities of contusive SCI in rats is positively correlated with serotonin immunoreactivity around motoneurons involved in the reflex (Lee, et al, 2005). That is, the greater their apparent chronic serotonergic (re)innervation the more abnormally elevated their reflex activation.…”

Section: Introductionmentioning

confidence: 98%

“…Properties of the H-reflex are known to be affected in both humans and rodents after SCI (Lee, et al, 2005, Schindler-Ivens and Shields, 2000, Thompson, et al, 1998, Valero-Cabre and Navarro, 2001. One of these alterations is elevated reflex amplitude that develops over time after SCI (Lee, et al, 2005, Thompson, et al, 1998.…”

Section: Introductionmentioning

confidence: 99%

“…One of these alterations is elevated reflex amplitude that develops over time after SCI (Lee, et al, 2005, Thompson, et al, 1998. The mechanism for this elevated reflex is still unclear.…”

Section: Introductionmentioning

confidence: 99%

“…We therefore investigated the role of 5-HT 2 R in the increased H-reflex amplitude observed after a standardized incomplete contusive SCI using a well-characterized rat model of injury (Basso, et al, 1996, Lee, et al, 2005, Pikov and Wrathall, 2001). We employed local intrathecal administration of the 5-HT 2 R antagonists, mianserin and LY53857, and the agonist, DOI, as well as immunohistochemistry of 5-HT 2 R expression on plantar motor neurons and found evidence in support of the hypothesis that increased 5-HT 2 R expression by plantar muscle motoneurons is causally related to the increased H-reflex amplitude of the plantar muscle after contusive SCI.…”

Section: Introductionmentioning

confidence: 99%

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Up-regulation of 5-HT2 receptors is involved in the increased H-reflex amplitude after contusive spinal cord injury

Lee

Johnson

Wrathall

2007

Experimental Neurology

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The amplitude of the H-reflex increases chronically after incomplete SCI and is associated with the development of exaggerated hindlimb reflexes. Although the mechanism for this increased H-reflex is not clear, previous studies have shown that pharmacological activation of the 5-HT 2 receptors (5-HT 2 R) can potentiate the monosynaptic reflex. This study tested the hypothesis that increased expression of 5-HT 2 R on motoneurons is involved in increased H-reflex amplitude after a standardized clinically-relevant contusive SCI. Adult female rats were subjected to contusion, complete surgical transection, or a T8 laminectomy only. At 4wks after surgery, H-reflex recordings from the hindpaw plantar muscles of contused rats showed twice the amplitude of that in laminectomy controls or transected rats. To probe the role of 5-HT 2 R in this increased amplitude, dose response studies were done with the selective antagonists, mianserin or LY53857, and the 5-HT 2 R agonist, (±)-1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI). The drugs were intrathecally infused into the lumbar cord while recording the H-reflex. Mianserin did not have any significant effects on the H-reflex after transection, consistent with the loss of distal serotonergic innervation. After contusion, both 5-HT 2 R antagonists reduced the H-reflex reflex amplitude with a significantly higher ID 50 compared to the uninjured controls. The 5-HT 2 R agonist, DOI, significantly increased reflex amplitude in contused but not control rats. Furthermore, while 5-HT immunoreactivity was similar, contused rats displayed increased 5-HT 2A R immunoreactivity in plantar muscle motoneurons compared to uninjured controls. We conclude that increased expression of 5-HT 2 R is likely to be involved in the enhanced H-reflex that develops after contusive SCI.

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Section: Spinal Cord Injury and Animal Carementioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

“…One of these alterations is elevated reflex amplitude that develops over time after SCI (Lee, et al, 2005, Thompson, et al, 1998. The mechanism for this elevated reflex is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Up-regulation of 5-HT2 receptors is involved in the increased H-reflex amplitude after contusive spinal cord injury

Lee

Johnson

Wrathall

2007

Experimental Neurology

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Spasticity Predicts Motor Recovery for Patients with Subacute Motor Complete Spinal Cord Injury

Sangari,

Chen,

Grover

et al. 2023

Annals of Neurology

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ObjectiveA motor complete spinal cord injury (SCI) results in the loss of voluntary motor control below the point of injury. Some of these patients can regain partial motor function through inpatient rehabilitation; however, there is currently no biomarker to easily identify which patients have this potential. Evidence indicates that spasticity could be that marker. Patients with motor complete SCI who exhibit spasticity show preservation of descending motor pathways, the pathways necessary for motor signals to be carried from the brain to the target muscle. We hypothesized that the presence of spasticity predicts motor recovery after subacute motor complete SCI.MethodsSpasticity (Modified Ashworth Scale and pendulum test) and descending connectivity (motor evoked potentials) were tested in the rectus femoris muscle in patients with subacute motor complete (n=36) and motor incomplete (n=30) SCI. Motor recovery was assessed by using the International Standards for Neurological Classification of Spinal Cord Injury and the American Spinal Injury Association Impairment Scale (AIS). All measurements were taken at admission and discharge from inpatient rehabilitation.ResultsWe found that motor complete SCI patients with spasticity improved in motor scores and showed AIS conversion to either motor or sensory incomplete. Conversely, patients without spasticity showed no changes in motor scores and AIS conversion. In incomplete SCI patients, motor scores improved and AIS conversion occurred regardless of spasticity.InterpretationThese findings indicate that spasticity represents an easy‐to‐use physiological biomarker to predict motor recovery after severe SCI. This knowledge can improve inpatient rehabilitation effectiveness for complete SCI patients.This article is protected by copyright. All rights reserved.

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Thermogelling chitosan lactate hydrogel improves functional recovery after a C2 spinal cord hemisection in rat

Nawrotek

Marqueste

Modrzejewska

et al. 2017

J Biomedical Materials Res

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The present study was designed to provide an appropriate micro-environment for regenerating axotomized neurons and proliferating/migrating cells. Because of its intrinsic permissive properties, biocompatibility and biodegradability, we chose to evaluate the therapeutic effectiveness of a chitosan-based biopolymer. The biomaterial toxicity was measured through in vitro test based on fibroblast cell survival on thermogelling chitosan lactate hydrogel substrate and then polymer was implanted into a C2 hemisection of the rat spinal cord. Animals were randomized into three experimental groups (Control, Lesion and Lesion + Hydrogel) and functional tests (ladder walking and forelimb grip strength tests, respiratory assessment by whole-body plethysmography measurements) were used, once a week during 10 weeks, to evaluate post-traumatic recoveries. Then, electrophysiological examinations (reflexivity of the sub-lesional region, ventilatory adjustments to muscle fatigue known to elicit the muscle metaboreflex and phrenic nerve recordings during normoxia and temporary hypoxia) were performed. In vitro results indicated that the chitosan matrix is a non-toxic biomaterial that allowed fibroblast survival. Furthermore, implanted animals showed improvements of their ladder walking scores from the 4th week post-implantation. Finally, electrophysiological recordings indicated that animals receiving the chitosan matrix exhibited recovery of the H-reflex rate sensitive depression, the ventilatory response to repetitive muscle stimulation and an increase of the phrenic nerve activity to asphyxia compared to lesioned and nonimplanted animals. This study indicates that hydrogel based on chitosan constitute a promising therapeutic approach to repair damaged spinal cord or may be used as an adjuvant with other treatments to enhance functional recovery after a central nervous system damage. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2004-2019, 2017.

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Effect of spinal cord injury severity on alterations of the H-reflex

Cited by 73 publications

References 58 publications

Up-regulation of 5-HT2 receptors is involved in the increased H-reflex amplitude after contusive spinal cord injury

Up-regulation of 5-HT2 receptors is involved in the increased H-reflex amplitude after contusive spinal cord injury

Spasticity Predicts Motor Recovery for Patients with Subacute Motor Complete Spinal Cord Injury

Thermogelling chitosan lactate hydrogel improves functional recovery after a C2 spinal cord hemisection in rat

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