Rostrocaudal distribution of motoneurones and variation in ventral horn area within a segment of the feline thoracic spinal cord

Single-unit electrical activity has been recorded from 122 viscerosomatic neurons in the T9 and T11 segments of the cat's spinal cord. These neurons were excited by electrical and/or natural stimulation of visceral and somatic afferent fibers. The majority of viscerosomatic neurons (72%) received somatic nociceptive inputs, either exclusively or together with low-threshold somatic inputs. Many of these neurons were excited most strongly by intense mechanical stimulation of subcutaneous tissues, particularly by pinching or squeezing muscle. Twelve viscerosomatic neurons were excited by distensions of the biliary system at levels of biliary pressure greater than 25 mmHg. These intensities of biliary stimulation evoked transient increases in blood pressure, which suggest that the visceral stimuli were of nociceptive nature. The effects of reversible spinalization by cold block were tested on 98 viscerosomatic neurons. Three subgroups of viscerosomatic neurons were distinguished depending on whether their responses to visceral afferent stimulation were increased, decreased, or unchanged in the spinal state. Forty percent of all neurons tested increased the intensity of their responses to visceral stimulation in the spinal state. In addition, many of these neurons developed or increased their background activity and increased their somatic responses in the spinal state. It is concluded that these neurons were subjected to tonic descending inhibition of both somatic and visceral afferent inputs. More than 40% of the neurons in this group were located in or close to lamina V of the dorsal horn. In 44% of all neurons tested the response to visceral stimulation was reduced or abolished by spinalization. The background activity was not affected in the same manner and sometimes even increased during spinalization. The responses to somatic stimuli were fully tested in 11 neurons of this group and were found to be decreased, but not abolished, in nine neurons, unchanged in one cell, and increased in another one. Many of the neurons in this group were located in the ventral horn (laminae VII and VIII). Sixteen percent of all viscerosomatic neurons tested showed no change in their responses to visceral stimulation during spinalization. It is concluded that the visceral input to viscerosomatic neurons in the lower thoracic spinal cord is under considerable descending control, which includes excitation as well as tonic inhibition of visceral afferent information. This may represent part of the widespread effects of visceral nociceptive stimulation.

Download Full-text

Ventral Horn Neuropeptides Modulate the Release of Noradrenaline from Tissue Slices of Rat Brainstem and Ventral Thoracic Spinal Cord

Journal of Neurochemistry ◽

10.1111/j.1471-4159.1991.tb08228.x ◽

1991 ◽

Vol 57 (3) ◽

pp. 845-851 ◽

Cited By ~ 6

Author(s):

Kevin C. F. Fone ◽

Janel V. Johnson ◽

Anthony P. Putland ◽

Geoffrey W. Bennett

Keyword(s):

Spinal Cord ◽

Ventral Horn ◽

Tissue Slices ◽

Thoracic Spinal Cord ◽

Release Of Noradrenaline ◽

Thoracic Spinal ◽

Rat Brainstem

Download Full-text

HISTOTOPOGRAPHY AND MORPHOMETRY OF THE VENTRAL HORN OF THE THORACIC SPINAL CORD IN THE POSTNATAL DEVELOPMENT OF WHITE RATS

Neuroscience for Medicine and Psychology ◽

10.29003/m523.sudak.ns2019-15/339 ◽

2019 ◽

Author(s):

Valentina Porseva ◽

Petr Masliukov

Keyword(s):

Spinal Cord ◽

Postnatal Development ◽

Ventral Horn ◽

Thoracic Spinal Cord ◽

White Rats ◽

Thoracic Spinal

Download Full-text

Electrophysiological and Morphological Characterization of Propriospinal Interneurons in the Thoracic Spinal Cord

Journal of Neurophysiology ◽

10.1152/jn.00738.2010 ◽

2011 ◽

Vol 105 (2) ◽

pp. 806-826 ◽

Cited By ~ 43

Author(s):

S. A. Saywell ◽

T. W. Ford ◽

C. F. Meehan ◽

A. J. Todd ◽

P. A. Kirkwood

Keyword(s):

Spinal Cord ◽

General Pattern ◽

Morphological Characterization ◽

Ventral Horn ◽

Trunk Muscles ◽

Respiratory Drive ◽

Thoracic Spinal Cord ◽

Antidromic Activation ◽

Thoracic Spinal ◽

Cord Injury

Propriospinal interneurons in the thoracic spinal cord have vital roles not only in controlling respiratory and trunk muscles, but also in providing possible substrates for recovery from spinal cord injury. Intracellular recordings were made from such interneurons in anesthetized cats under neuromuscular blockade and with the respiratory drive stimulated by inhaled CO2. The majority of the interneurons were shown by antidromic activation to have axons descending for at least two to four segments, mostly contralateral to the soma. In all, 81% of the neurons showed postsynaptic potentials (PSPs) to stimulation of intercostal or dorsal ramus nerves of the same segment for low-threshold (≤5T) afferents. A monosynaptic component was present for the majority of the peripherally evoked excitatory PSPs. A central respiratory drive potential was present in most of the recordings, usually of small amplitude. Neurons depolarized in either inspiration or expiration, sometimes variably. The morphology of 17 of the interneurons and/or of their axons was studied following intracellular injection of Neurobiotin; 14 axons were descending, 6 with an additional ascending branch, and 3 were ascending (perhaps actually representing ascending tract cells); 15 axons were crossed, 2 ipsilateral, none bilateral. Collaterals were identified for 13 axons, showing exclusively unilateral projections. The collaterals were widely spaced and their terminations showed a variety of restricted locations in the ventral horn or intermediate area. Despite heterogeneity in detail, both physiological and morphological, which suggests heterogeneity of function, the projections mostly fitted a consistent general pattern: crossed axons, with locally weak, but widely distributed terminations.

Download Full-text

Spontaneous Herniation of the Thoracic Spinal Cord: A Case Report

Journal of the Korean Radiological Society ◽

10.3348/jkrs.2001.45.4.353 ◽

2001 ◽

Vol 45 (4) ◽

pp. 353 ◽

Cited By ~ 1

Author(s):

Sung Chan Jin ◽

Seoung Ro Lee ◽

Dong Woo Park ◽

Kyung Bin Joo

Keyword(s):

Spinal Cord ◽

Case Report ◽

Thoracic Spinal Cord ◽

Thoracic Spinal ◽

Spontaneous Herniation

Download Full-text

Lipomeningocele associated with diplomyelia in a dog

Tierärztliche Praxis Ausgabe K Kleintiere / Heimtiere ◽

10.15654/tpk-170751 ◽

2018 ◽

Vol 46 (05) ◽

pp. 323-329 ◽

Cited By ~ 2

Author(s):

Nele Ondreka ◽

Sara Malberg ◽

Emma Laws ◽

Martin Schmidt ◽

Sabine Schulze

Keyword(s):

Spinal Cord ◽

Neurological Status ◽

Split Cord Malformation ◽

Lumbar Spinal Cord ◽

Histopathological Diagnosis ◽

Type I ◽

Thoracic Spinal Cord ◽

Thoracic Spinal ◽

Subcutaneous Mass ◽

Lumbar Spinal

SummaryA 2-year-old male neutered mixed breed dog with a body weight of 30 kg was presented for evaluation of a soft subcutaneous mass on the dorsal midline at the level of the caudal thoracic spine. A further clinical sign was intermittent pain on palpation of the area of the subcutaneous mass. The owner also described a prolonged phase of urination with repeated interruption and re-initiation of voiding. The findings of the neurological examination were consistent with a lesion localization between the 3rd thoracic and 3rd lumbar spinal cord segments. Magnetic resonance imaging revealed a spina bifida with a lipomeningocele and diplomyelia (split cord malformation type I) at the level of thoracic vertebra 11 and 12 and secondary syringomyelia above the aforementioned defects in the caudal thoracic spinal cord. Surgical resection of the lipomeningocele via a hemilaminectomy was performed. After initial deterioration of the neurological status postsurgery with paraplegia and absent deep pain sensation the dog improved within 2 weeks to non-ambulatory paraparesis with voluntary urination. Six weeks postoperatively the dog was ambulatory, according to the owner. Two years after surgery the owner recorded that the dog showed a normal gait, a normal urination and no pain. Histopathological diagnosis of the biopsied material revealed a lipomeningocele which confirmed the radiological diagnosis.

Download Full-text

Effect of thoracic spinal cord injury on forelimb somatosensory evoked potential

Brain Research Bulletin ◽

10.1016/j.brainresbull.2021.05.005 ◽

2021 ◽

Author(s):

Angelo H. All ◽

Shiyu Luo ◽

Xiaogang Liu ◽

Hasan Al-Nashash

Keyword(s):

Spinal Cord ◽

Spinal Cord Injury ◽

Evoked Potential ◽

Somatosensory Evoked Potential ◽

Thoracic Spinal Cord ◽

Thoracic Spinal ◽

Cord Injury

Download Full-text

The Histopathology of Severe Graded Compression in Lower Thoracic Spinal Cord Segment of Rat, Evaluated at Late Post-injury Phase

Cellular and Molecular Neurobiology ◽

10.1007/s10571-021-01139-7 ◽

2021 ◽

Author(s):

Fedorova Jana ◽

Kellerova Erika ◽

Bimbova Katarina ◽

Pavel Jaroslav

Keyword(s):

Spinal Cord ◽

Spontaneous Recovery ◽

Traumatic Injury ◽

Blue Dye ◽

Post Injury ◽

Thoracic Spinal Cord ◽

Thoracic Spinal ◽

Severe Traumatic Injury ◽

Spinal Cord Segment ◽

Cord Injury

AbstractSpontaneous recovery of lost motor functions is relative fast in rodent models after inducing a very mild/moderate spinal cord injury (SCI), and this may complicate a reliable evaluation of the effectiveness of potential therapy. Therefore, a severe graded (30 g, 40 g and 50 g) weight-compression SCI at the Th9 spinal segment, involving an acute mechanical impact followed by 15 min of persistent compression, was studied in adult female Wistar rats. Functional parameters, such as spontaneous recovery of motor hind limb and bladder emptying function, and the presence of hematuria were evaluated within 28 days of the post-traumatic period. The disruption of the blood-spinal cord barrier, measured by extravasated Evans Blue dye, was examined 24 h after the SCI, when maximum permeability occurs. At the end of the survival period, the degradation of gray and white matter associated with the formation of cystic cavities, and quantitative changes of glial structural proteins, such as GFAP, and integral components of axonal architecture, such as neurofilaments and myelin basic protein, were evaluated in the lesioned area of the spinal cord. Based on these functional and histological parameters, and taking the animal’s welfare into account, the 40 g weight can be considered as an upper limit for severe traumatic injury in this compression model.

Download Full-text