Monkey Recovery from Spinal Cord Hemisection: Nerve Repair Strategies for Rhesus Macaques

The aim of the present study was to specifically investigate the involvement of serotonin [5-hydroxytryptamine (5-HT2)] receptors in 5-HT-mediated respiratory recovery after cervical hemisection. Experiments were conducted on C2 spinal cord-hemisected, anesthetized (chloral hydrate, 400 mg/kg ip), vagotomized, pancuronium- paralyzed, and artificially ventilated female Sprague-Dawley rats in which CO2 levels were monitored and maintained. Twenty-four hours after spinal hemisection, the ipsilateral phrenic nerve displayed no respiratory-related activity indicative of a functionally complete hemisection. Intravenous administration of the 5-HT2A/2C-receptor agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) induced respiratory-related activity in the phrenic nerve ipsilateral to hemisection under conditions in which CO2 was maintained at constant levels and augmented the activity induced under conditions of hypercapnia. The effects of DOI were found to be dose dependent, and the recovery of activity could be maintained for up to 2 h after a single injection. DOI-induced recovery was attenuated by the 5-HT2-receptor antagonist ketanserin but not with the 5-HT2C-receptor antagonist RS-102221, suggesting that 5-HT2A and not necessarily 5-HT2C receptors may be involved in the induction of respiratory recovery after cervical spinal cord injury.

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Identification of the axon pathways which mediate functional recovery of a paralyzed hemidiaphragm following spinal cord hemisection in the adult rat

Experimental Neurology ◽

10.1016/0014-4886(92)90001-7 ◽

1992 ◽

Vol 116 (3) ◽

pp. 219-228 ◽

Cited By ~ 84

Author(s):

Dale E. Moreno ◽

Xiao-Jun Yu ◽

Harry G. Goshgarian

Keyword(s):

Spinal Cord ◽

Functional Recovery ◽

Adult Rat ◽

Spinal Cord Hemisection

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Theophylline-induced respiratory recovery following cervical spinal cord hemisection is augmented by serotonin 2 receptor stimulation

Brain Research ◽

10.1016/s0006-8993(02)03097-4 ◽

2002 ◽

Vol 956 (1) ◽

pp. 1-13 ◽

Cited By ~ 16

Author(s):

Gregory J Basura ◽

Kwaku D Nantwi ◽

Harry G Goshgarian

Keyword(s):

Spinal Cord ◽

Cervical Spinal Cord ◽

Receptor Stimulation ◽

Respiratory Recovery ◽

Spinal Cord Hemisection

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Effects of early nerve repair on experimental brachial plexus injury in neonatal rats

Journal of Hand Surgery (European Volume) ◽

10.1177/1753193417732696 ◽

2017 ◽

Vol 43 (3) ◽

pp. 275-281 ◽

Cited By ~ 1

Author(s):

Gráinne Bourke ◽

Aleksandra M. McGrath ◽

Mikael Wiberg ◽

Lev N. Novikov

Keyword(s):

Spinal Cord ◽

Brachial Plexus ◽

Brachial Plexus Injury ◽

Neuroprotective Effect ◽

Nerve Repair ◽

Neonatal Rats ◽

Spinal Motoneurons ◽

Muscle Weight ◽

Retrograde Degeneration ◽

Dendritic Branches

Obstetrical brachial plexus injury refers to injury observed at the time of delivery, which may lead to major functional impairment in the upper limb. In this study, the neuroprotective effect of early nerve repair following complete brachial plexus injury in neonatal rats was examined. Brachial plexus injury induced 90% loss of spinal motoneurons and 70% decrease in biceps muscle weight at 28 days after injury. Retrograde degeneration in spinal cord was associated with decreased density of dendritic branches and presynaptic boutons and increased density of astrocytes and macrophages/microglial cells. Early repair of the injured brachial plexus significantly delayed retrograde degeneration of spinal motoneurons and reduced the degree of macrophage/microglial reaction but had no effect on muscle atrophy. The results demonstrate that early nerve repair of neonatal brachial plexus injury could promote survival of injured motoneurons and attenuate neuroinflammation in spinal cord.

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Spinal Cord Hemisection Facilitates Aromatic L-Amino Acid Decarboxylase Cells to Produce Serotonin in the Subchronic but Not the Chronic Phase

Neural Plasticity ◽

10.1155/2015/549671 ◽

2015 ◽

Vol 2015 ◽

pp. 1-10 ◽

Cited By ~ 4

Author(s):

Bushra Azam ◽

Jacob Wienecke ◽

Dennis Bo Jensen ◽

Aleena Azam ◽

Mengliang Zhang

Keyword(s):

Spinal Cord ◽

Amino Acid ◽

Chronic Phase ◽

Acid Decarboxylase ◽

Partial Loss ◽

Adult Rats ◽

Amino Acid Decarboxylase ◽

Thoracic Level ◽

Plastic Changes ◽

Spinal Cord Hemisection

Neuromodulators, such as serotonin (5-hydroxytryptamine, 5-HT) and noradrenalin, play an essential role in regulating the motor and sensory functions in the spinal cord. We have previously shown that in the rat spinal cord the activity of aromatic L-amino acid decarboxylase (AADC) cells to produce 5-HT from its precursor (5-hydroxytryptophan, 5-HTP) is dramatically increased following complete spinal cord transection. In this study, we investigated whether a partial loss of 5-HT innervation could similarly increase AADC activity. Adult rats with spinal cord hemisected at thoracic level (T11/T12) were used with a postoperation interval at 5 days or 60 days. Using immunohistochemistry, first, we observed a significant reduction in the density of 5-HT-immunoreactive fibers in the spinal cord below the lesion on the injured side for both groups. Second, we found that the AADC cells were similarly expressed on both injured and uninjured sides in both groups. Third, increased production of 5-HT in AADC cells following 5-HTP was seen in 5-day but not in 60-day postinjury group. These results suggest that plastic changes of the 5-HT system might happen primarily in the subchronic phase and for longer period its function could be compensated by plastic changes of other intrinsic and/or supraspinal modulation systems.

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