A serotonin-immunoreactive fiber system in the dorsal columns of the spinal cord

1982 ◽  
Vol 31 (3) ◽  
pp. 247-252 ◽  
Author(s):  
Michael B. Hancock
Keyword(s):  
Spinal Cord ◽  
Fiber System ◽  
Dorsal Columns ◽  
Immunoreactive Fiber

Histopathology of experimental hematomyelia

1991 ◽  
Vol 75 (6) ◽  
pp. 911-915 ◽  
Author(s):  
Thomas H. Milhorat ◽  
David E. Adler ◽  
Ian M. Heger ◽  
John I. Miller ◽  
Joanna R. Hollenberg-Sher
Keyword(s):  
Spinal Cord ◽  
Tissue Injury ◽  
Central Canal ◽  
Microglial Cells ◽  
Neurological Deficits ◽  
Thoracic Spinal Cord ◽  
Content Type ◽  
Thoracic Spinal ◽  
Cellular Debris ◽  
Dorsal Columns

✓ The pathology of hematomyelia was examined in 35 rats following the stereotactic injection of 2 µl blood into the dorsal columns of the thoracic spinal cord. This experimental model produced a small ball-hemorrhage without associated neurological deficits or significant tissue injury. Histological sections of the whole spinal cord were studied at intervals ranging from 2 hours to 4 months after injection. In acute experiments (2 to 6 hours postinjection), blood was sometimes seen within the lumen of the central canal extending rostrally to the level of the fourth ventricle. Between 24 hours and 3 days, the parenchymal hematoma became consolidated and there was an intense proliferation of microglial cells at the perimeter of the lesion. The cells invaded the hematoma, infiltrated its core, and removed erythrocytes by phagocytosis. Rostral to the lesion, the lumen of the central canal was found to contain varying amounts of fibrin, proteinaceous material, and cellular debris for up to 15 days. These findings were much less prominent in the segments of the canal caudal to the lesion. Healing of the parenchymal hematoma was usually complete within 4 to 6 weeks except for residual hemosiderin-laden microglial cells and focal gliosis at the lesion site. It is concluded that the clearance of atraumatic hematomyelia probably involves two primary mechanisms: 1) phagocytosis of the focal hemorrhage by microglial cells; and 2) drainage of blood products in a rostral direction through the central canal of the spinal cord.

Spatiotemporal CCR1, CCL3(MIP-1α), CXCR4, CXCL12(SDF-1α) expression patterns in a rat spinal cord injury model of posttraumatic neuropathic pain

2011 ◽  
Vol 14 (5) ◽  
pp. 583-597 ◽  
Author(s):  
Friederike Knerlich-Lukoschus ◽  
Beata von der Ropp-Brenner ◽  
Ralph Lucius ◽  
Hubertus Maximilian Mehdorn ◽  
Janka Held-Feindt
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Neuropathic Pain ◽  
Substance P ◽  
Time Course ◽  
Behavioral Testing ◽  
Dorsal Horns ◽  
Cord Injury ◽  
Dorsal Columns ◽  
Spinal Cord Contusion

Object Central neuropathic pain is a frequent challenging complication after spinal cord injury (SCI), and specific therapeutic approaches remain elusive. The purpose of the present investigations was to identify potential key mediators of these pain syndromes by analyzing detailed expression profiles of important chemokines in an experimental SCI paradigm of posttraumatic neuropathic pain in rats. Methods Expression of CCR1, CCL3(MIP-1α), CXCR4, and CXCL12(SDF-1α) was investigated in parallel with behavioral testing for mechanical and thermal nociceptive thresholds after standardized SCI; 100-kdyn (moderate injury) and 200-kdyn (severe injury) force-defined thoracic spinal cord contusion lesions were applied via an Infinite Horizon Impactor at the T-9 level. Sham controls received laminectomies. Hindlimb locomotor function as well as mechanical and thermal sensitivities were monitored weekly by standardized behavioral testing after SCI. Chemokine expression was analyzed by real-time reverse transcriptase polymerase chain reaction in the early (7 days postoperatively) and late (42 days postoperatively) time courses after SCI, and immunohistochemical analysis (anatomical and quantitative) was performed 2, 7, 14, and 42 days after lesioning. Double staining with cellular markers and pain-related peptides (substance P and CGRP) or receptors (TRPV-1, TRPV-2, VRL-1, and TLR-4) was performed. Based on data obtained from behavioral testing, quantified immunohistochemical chemokine expressions in individual animals were correlated with the respective mechanical and thermal sensitivity thresholds 6 weeks after SCI. Results After 200-kdyn lesions, the animals exhibited prolonged reduction in their nociceptive thresholds, while 100-kdyn groups showed pain-related behaviors only in the early time course after SCI. Investigated chemokines were widely induced after SCI, involving cervical, thoracic, and lumbar spinal cord levels far beyond the lesion core. CCR1 and CCL3 were induced significantly in the dorsal horns 2 days after lesioning and remained at high levels after SCI with significantly higher intensities after 200-kdyn than 100-kdyn contusions. CXCR4 and CXCL12 levels continuously increased from 2 to 42 days after moderate and severe lesions. Additionally, chemokines were induced significantly in dorsal columns, with highest density levels 42 days after 200-kdyn lesions. In dorsal horns, CCR1 was coexpressed with TRPV-1 while CXCR4 and CXCL12 were partially coexpressed with substance P and CGRP. In dorsal columns, CCL3/CCR1 colabeled with GFAP, TRPV-2, TRPV-1, TLR-4; CXCR4/CXCL12 coexpressed with GFAP, CD68/ED1, and TLR4. Chemokine immunoreactivity density levels, especially CCL3 and its receptor, correlated in part significantly with nociceptive thresholds. Conclusions The authors report lesion grade–dependent upregulation of different chemokines/chemokine receptors after spinal cord contusion lesions in pain-processing spinal cord regions in a clinically relevant model of traumatic SCI in rats. Prolonged chemokine induction further correlated with below-level pain development in the delayed time course after severe SCI and was coexpressed with pain-associated peptides and receptors, suggesting that chemokines play a crucial role in chronic central pain mechanisms after SCI.

Nitrous Oxide Abuse‐Induced Subacute Combined Degeneration: Classic Neuroimaging Findings on MRI

Neurographics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 72-74
Author(s):  
A.K. Kirsch ◽  
S.M. Allison ◽  
S.A. Kilanowski
Keyword(s):  
Spinal Cord ◽  
Nitrous Oxide ◽  
Mr Imaging ◽  
Young Patient ◽  
Patient Population ◽  
High Signal ◽  
Vitamin B ◽  
Subacute Combined Degeneration ◽  
Dorsal Columns ◽  
Delay In Treatment

Subacute combined degeneration is uncommonly a result of nitrous oxide abuse and presents with high signal in the dorsal columns of the spinal cord on T2-weighted MR imaging. We present a case of subacute combined degeneration in a young patient who abused nitrous oxide, which is an uncommon cause and infrequently seen in this patient population. Symptoms are often reversible with treatment of vitamin B12, and radiologists should be aware of these findings to avoid delay in treatment.

Ascending pathways in the spinal cord involved in the activation of subnucleus reticularis dorsalis neurons in the medulla of the rat

1990 ◽  
Vol 63 (3) ◽  
pp. 424-438 ◽  
Author(s):  
Z. Bing ◽  
L. Villanueva ◽  
D. Le Bars
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
The Body ◽  
Cervical Cord ◽  
Lateral Part ◽  
Neuronal Responses ◽  
C Fiber ◽  
Dorsal Columns ◽  
Dorsolateral Funiculus ◽  
The Right

1. Recordings were made from neurons in the left medullary subnucleus reticularis dorsalis (SRD) of anesthetized rats. Two populations of neurons were recorded: neurons with total nociceptive convergence (TNC), which gave responses to A delta- and C-fiber activation from the entire body after percutaneous electrical stimulation, and neurons with partial nociceptive convergence (PNC), which responded to identical stimuli with an A delta-peak regardless of which part of the body was stimulated and with a C-fiber peak of activation from some, mainly contralateral, parts of the body. 2. The effects of various, acute, transverse sections of the cervical (C4-C5) spinal cord on the A delta- and C-fiber-evoked responses were investigated by building poststimulus histograms (PSHs) after 50 trials of supramaximal percutaneous electrical stimulation of the extremity of either hindpaw (2-ms duration; 3 times threshold for C-fiber responses), before and 30-40 min after making the spinal lesion. 3. In the case of TNC neurons, hemisections of the left cervical cord blocked the responses elicited from the right hindpaw and slightly, but not significantly, diminished those evoked from the left hindpaw. Conversely, hemisections of the right cervical cord abolished TNC responses elicited from the left hindpaw without significantly affecting the responses elicited from the right hindpaw. 4. Lesioning the dorsal columns or the left dorsolateral funiculus was found not to affect the TNC neuronal responses elicited from either hindpaw. By contrast, lesioning the left lateral funiculus or the most lateral part of the ventrolateral funiculus, respectively, reduced and blocked the responses elicited from the right hindpaw without affecting those evoked from the left hindpaw. 5. After lesions that included the most lateral parts of the left ventral funiculus, PNC neuronal responses elicited from the right hindpaw were also abolished, whereas those elicited from the left hindpaw remained unchanged. 6. We conclude that the signals responsible for the activation of SRD neurons travel principally in the lateral parts of the ventrolateral quadrant, a region that classically has been implicated in the transmission of noxious information. Both a crossed and a double-crossed pathway are involved in this process. The postsynaptic fibers of the dorsal columns and the spinocervical and spinomesencephalic tracts do not appear to convey signals that activate SRD neurons. 7. The findings also suggest that lamina I nociceptive specific neurons, the axons of which travel within the dorsolateral funiculus, do not contribute very much to the activation of SRD neurons.

Intraoperative evoked potentials recorded in man directly from dorsal roots and spinal cord

1985 ◽  
Vol 62 (5) ◽  
pp. 680-693 ◽  
Author(s):  
Blaine S. Nashold ◽  
Janice Ovelmen-Levitt ◽  
Robbin Sharpe ◽  
Alfred C. Higgins
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Mean Amplitude ◽  
Dorsal Column ◽  
Intractable Pain ◽  
Neurosurgical Procedures ◽  
Negative Wave ◽  
Content Type ◽  
Root Entry Zone ◽  
Dorsal Columns

✓ Direct spinal cord surface recordings of evoked spinal cord potentials have been made in 26 patients during neurosurgical procedures for intractable pain. Monopolar recordings at the dorsal root entry zone after peripheral nerve stimulation have been made at multiple levels for segmental localization and to monitor the state of the afferent path and dorsal horn. Dorsal root and dorsal column conduction has been tested on diseased and intact sides. Normal afferent conduction velocity was found to have an overall mean of 61.33 m/sec for cervicothoracic and lumbosacral peripheral nerves, and 50 m/sec for the dorsal columns. The normal mean amplitude for the slow negative wave (N1) recorded at the root entry was 52.54 µV, while that for the dorsal column conducted response recorded within 4 cm of the stimulus point on the dorsal columns was 347.5 µV. Several different placements of stimulating and recording electrodes are described, as well as their application. An interpretation of the resulting data is proposed.

scholarly journals Sensory afferents regenerated into dorsal columns after spinal cord injury remain in a chronic pathophysiological state

2007 ◽  
Vol 206 (2) ◽  
pp. 257-268 ◽  
Author(s):  
Andrew M. Tan ◽  
Jeffrey C. Petruska ◽  
Lorne M. Mendell ◽  
Joel M. Levine
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Sensory Afferents ◽  
Cord Injury ◽  
Dorsal Columns

New Trends in Neuromodulation for the Management of Neuropathic Pain

Neurosurgery ◽  
2002 ◽  
Vol 50 (4) ◽  
pp. 690-704 ◽  
Author(s):  
Kenneth M. Aló ◽  
Jan Holsheimer
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
Clinical Results ◽  
Intractable Pain ◽  
Long Term Effects ◽  
Long Term Outcomes ◽  
Dorsal Columns ◽  
Painful Area ◽  
Electronic Field

Abstract SINCE ITS FIRST application in 1967, the methodology and technology of spinal cord stimulation for the management of chronic, intractable pain have evolved continuously. Despite these developments and improved knowledge of the effects of spinal anatomy and epidural contact configuration on paresthesia coverage, the clinical results of spinal cord stimulation—particularly the long-term effects—are still unsatisfactory in many patients. This dissatisfaction has come primarily from the failure of single-electrode configurations to provide consistent paresthesia coverage of the entire painful area. Therefore, new approaches were developed during the late 1990s that attempted to selectively cover one or more dermatomes with paresthesia as well as to provide sequential stimulation of different anatomic sites. These approaches have been applied both intraspinally and extraspinally by stimulating either the spinal nerves or the dorsal columns. To target parts of the latter, different methods have been developed and tested using either two-dimensional contact configurations or electronic field steering. These developments hold promise for improving long-term outcomes as well as increasing the number of pain conditions that can be treated with neuromodulation therapy. In this review, the history, theoretical basis, and evolution of these methodologies, as well as the ways in which they represent new trends in neuromodulation, are discussed.

Spinal evoked potentials from the motor tracts

1983 ◽  
Vol 58 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Walter J. Levy
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor System ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Dorsal Column ◽  
Content Type ◽  
Dorsal Columns ◽  
Evoked Potential Monitoring ◽  
Potential Monitoring

✓ There is a need to monitor the motor system, but it has a different blood supply and a different location in the spinal cord from those measured by traditional somatosensory evoked potential monitoring. This paper reports a motor evoked potential monitoring system that uses direct spinal cord stimulation overlying the areas of the motor tract in the cord. In nine cats, evoked potentials were recorded from the dura, which gave a much faster main signal component than the traditional dorsal column evoked potentials, which were also recorded. This 100-m/sec signal was not affected by sectioning of the dorsal columns, which was verified histologically. This mode of monitoring the motor system can be used during surgery. It may also provide a better evaluation of patients after spinal cord trauma.

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