PNMT-containing neurons of the C1 cell group express c-fos in response to changes in baroreceptor input

1994 ◽  
Vol 266 (2) ◽  
pp. R361-R367 ◽  
Author(s):  
A. F. Sved ◽  
D. L. Mancini ◽  
J. C. Graham ◽  
A. M. Schreihofer ◽  
G. E. Hoffman
Keyword(s):  
Afferent Input ◽  
Protein Product ◽  
Early Gene ◽  
Ventrolateral Medulla ◽  
Cell Group ◽  
Afferent Activity ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Upper Thoracic

The immunocytochemical detection of Fos, the protein product of the immediate-early gene c-fos, was used as a marker for activated neurons to examine whether the C1 neurons in the rat rostral ventrolateral medulla (RVLM) respond to changes in baroreceptor afferent activity. After hydralazine-induced hypotension or sinoaortic denervation, two treatments that reduce baroreceptor afferent activity, numerous Fos-positive neurons were observed in the RVLM. The number of Fos-positive neurons in the RVLM was counted in brain stem sections from hydralazine-treated rats that had been previously injected with Fluorogold into the upper thoracic spinal cord to label spinally projecting RVLM neurons as well as stained for phenylethanolamine-N-methyltransferase (PNMT) as a marker of C1 neurons. The results indicate that approximately 80% of the C1 neurons expressed Fos in response to hydralazine injection; this was true of spinally projecting C1 neurons as well as those C1 neurons that were not labeled with Fluorogold. Furthermore, in hydralazine-treated rats, the majority of Fluorogold-labeled Fos-positive neurons contained PNMT. These results suggest that C1 neurons are sensitive to baroreceptor afferent input and support a role of these neurons in cardiovascular regulation.

Role of presympathetic C1 neurons in the sympatholytic and hypotensive effects of clonidine in rats

2000 ◽  
Vol 279 (5) ◽  
pp. R1753-R1762 ◽  
Author(s):  
Ann M. Schreihofer ◽  
Patrice G. Guyenet
Keyword(s):  
Extracellular Recording ◽  
Splanchnic Nerve ◽  
Cell Types ◽  
Ventrolateral Medulla ◽  
Thoracic Spinal Cord ◽  
Catecholaminergic Neurons ◽  
Thoracic Spinal ◽  
Multiple Cell ◽  
Rvlm Neuron

The rostral ventrolateral medulla (RVLM) may play an important role in the sympatholytic and hypotensive effects of clonidine. The present study examined which type of presympathetic RVLM neuron is inhibited by clonidine, and whether the adrenergic presympathetic RVLM neurons are essential for clonidine-induced sympathoinhibition. In chloralose-anesthetized and ventilated rats, clonidine (10 μg/kg iv) decreased arterial pressure (116 ± 6 to 84 ± 2 mmHg) and splanchnic nerve activity (93 ± 3% from baseline). Extracellular recording and juxtacellular labeling of barosensitive bulbospinal RVLM neurons revealed that most cells were inhibited by clonidine (26/28) regardless of phenotype [tyrosine hydroxylase (TH)-immunoreactive cells: 48 ± 7%; non-TH-immunoreactive cells: 42 ± 5%], although the inhibition of most neurons was modest compared with the observed sympathoinhibition. Depletion of most bulbospinal catecholaminergic neurons, including 76 ± 5% of the rostral C1 cells, by microinjection of saporin anti-dopamine β-hydroxylase into the thoracic spinal cord (levels T2 and T4, 42 ng · 200 nl−1 · side−1) did not alter the sympatholytic or hypotensive effects of clonidine. These data show that although clonidine inhibits presympathetic C1 neurons, bulbospinal catecholaminergic neurons do not appear to be essential for the sympatholytic and hypotensive effects of systemically administered clonidine. Instead, the sympatholytic effect of clonidine is likely the result of a combination of effects on multiple cell types both within and outside the RVLM.

scholarly journals Exaggerated sympathoexcitatory reflexes develop with changes in the rostral ventrolateral medulla in obese Zucker rats

2016 ◽  
Vol 311 (2) ◽  
pp. R243-R253 ◽  
Author(s):  
Domitila A. Huber ◽  
Ann M. Schreihofer
Keyword(s):  
Sciatic Nerve ◽  
Nerve Stimulation ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Zucker Rats ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Obese Zucker Rats ◽  
Sciatic Nerve Stimulation ◽  
Upper Thoracic

Obesity leads to altered autonomic reflexes that reduce stability of mean arterial pressure (MAP). Sympathoinhibitory reflexes such as baroreflexes are impaired, but reflexes that raise MAP appear to be augmented. In obese Zucker rats (OZR) sciatic nerve stimulation evokes larger increases in MAP by unknown mechanisms. We sought to determine the autonomic underpinnings of this enhanced somatic pressor reflex and whether other sympathoexcitatory reflexes are augmented. We also determined whether their final common pathway, glutamatergic activation of the rostral ventrolateral medulla (RVLM), was enhanced in male OZR compared with lean Zucker rats (LZR). Sciatic nerve stimulation or activation of the nasopharyngeal reflex evoked larger rises in splanchnic sympathetic nerve activity (SNA) (79% and 45% larger in OZR, respectively; P < 0.05) and MAP in urethane-anesthetized, ventilated, paralyzed adult OZR compared with LZR. After elimination of baroreflex feedback by pharmacological prevention of changes in MAP and heart rate, these two sympathoexcitatory reflexes were still exaggerated in OZR (167% and 69% larger, respectively, P < 0.05). In adult OZR microinjections of glutamate, AMPA, or NMDA into the RVLM produced larger rises in SNA (∼61% larger in OZR, P < 0.05 for each drug) and MAP, but stimulation of axonal fibers in the upper thoracic spinal cord yielded equivalent responses in OZR and LZR. In juvenile OZR and LZR, sympathoexcitatory reflexes and physiological responses to RVLM activation were comparable. These data suggest that the ability of glutamate to activate the RVLM becomes enhanced in adult OZR and may contribute to the development of exaggerated sympathoexcitatory responses independent of impaired baroreflexes.

An upper thoracic spinal cord tumor presenting as hemifacial hyperhidrosis

2007 ◽  
Vol 68 (4) ◽  
pp. 461-463 ◽  
Author(s):  
Cumhur Kilinçer ◽  
Levent Öztürk ◽  
M. Kemal Hamamcioglu ◽  
Emre Altunrende ◽  
Sebahattin Çobanoglu
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Tumor ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Upper Thoracic

scholarly journals Upper thoracic spinal cord herniation after traumatic nerve root avulsion

2004 ◽  
Vol 16 (5) ◽  
pp. 306-309
Author(s):  
Victor R. DaSilva ◽  
Mubarak Al-Gahtany ◽  
Rajiv Midha ◽  
Dipanka Sarma ◽  
Perry Cooper
Keyword(s):  
Spinal Cord ◽  
Nerve Root ◽  
Signs And Symptoms ◽  
Root Avulsion ◽  
Thoracic Spinal Cord ◽  
First Case ◽  
Thoracic Spinal ◽  
Spinal Cord Herniation ◽  
Nerve Root Avulsion ◽  
Upper Thoracic

✓ Transdural herniation of the spinal cord, a rare but well-documented entity, has been reported sporadically for more than 25 years as a possible cause for various neurological signs and symptoms ranging from isolated sensory or motor findings to myelopathy and Brown–Séquard syndrome. The authors report, to the best of their knowledge, the first case of upper thoracic spinal cord herniation occurring after traumatic nerve root avulsion.

Spinal NMDA receptors mediate pressor responses evoked from the rostral ventrolateral medulla

1991 ◽  
Vol 260 (1) ◽  
pp. H267-H275 ◽  
Author(s):  
M. K. Bazil ◽  
F. J. Gordon
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Nmda Receptors ◽  
Excitatory Amino Acid ◽  
Cardiovascular Responses ◽  
Rostral Ventrolateral Medulla ◽  
Ventrolateral Medulla ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Pressor Responses

These studies investigated the role of spinal N-methyl-D-aspartic acid (NMDA) receptors in the mediation of cardiovascular responses evoked by L-glutamate (L-Glu) stimulation of the rostral ventrolateral medulla (RVM). Microinjections of L-Glu into the RVM of urethan-anesthetized rats increased mean arterial pressure (MAP) and heart rate. Intrathecal administration of the NMDA receptor antagonists D-(-)-2-amino-7-phosphonoheptanoic acid (D-AP-7) or 3-((+-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonate (CPP) reduced MAP and heart rate. Blockade of NMDA receptors by D-AP-7 or CPP in the caudal thoracic spinal cord markedly reduced RVM pressor responses with little effect on evoked tachycardia. Administration of D-AP-7 to the rostral thoracic spinal cord had no effect on RVM pressor or tachycardic responses. Intrathecal D-AP-7 and CPP abolished the cardiovascular effects of intrathecal NMDA without reducing those produced by intrathecal kainic acid or the quisqualate agonist DL-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA). These results indicate that 1) tonic activation of spinal NMDA receptors participates in the maintenance of sympathetic outflow to the heart and blood vessels, 2) pressor responses evoked from the RVM require synaptic activation of spinal NMDA receptors, and 3) an excitatory amino acid may be the neurotransmitter of pressor pathways descending from the RVM to the spinal cord.

scholarly journals Role of expansile duraplasty and neural monitoring in surgery for Anterior Thoracic Spinal Cord Herniation

2020 ◽  
Vol 22 ◽  
pp. 100859
Author(s):  
Venugopal Sarath Chander ◽  
Ramachandran Govindasamy ◽  
Dheeraj Masapu ◽  
Veeramani Preethish-Kumar ◽  
Satish Rudrappa
Keyword(s):  
Spinal Cord ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Spinal Cord Herniation ◽  
Neural Monitoring

Responses of T2-4 spinal cord neurons to irritation of the lower airways in the rat

1997 ◽  
Vol 273 (3) ◽  
pp. R1147-R1157 ◽  
Author(s):  
T. Hummel ◽  
J. N. Sengupta ◽  
S. T. Meller ◽  
G. F. Gebhart
Keyword(s):  
Spinal Cord ◽  
Afferent Input ◽  
Sprague Dawley ◽  
Spinal Neurons ◽  
Thoracic Spinal Cord ◽  
Spinal Cord Neurons ◽  
Thoracic Spinal ◽  
Balloon Distension ◽  
Sprague Dawley Rats ◽  
Lower Airways

The aim of the study was to investigate the information processing in the thoracic spinal cord (T2-4) after chemical irritation of the lower airways. Experiments were performed in pentobarbital sodium-anesthetized and pancuronium-paralyzed male Sprague-Dawley rats. Balloon distension of the esophagus was used as the search stimulus. Ammonia and smoke were applied by means of a tracheal cannula; they produced excitatory, inhibitory, and biphasic responses in a concentration-related manner (ammonia 39/39; smoke 23/ 39). Inhaled irritant-responsive neurons exhibited a number of similarities that have been described for neurons responding to stimulation of other thoracic viscera. These similarities relate to the distribution of neurons in the deeper laminae of the thoracic spinal cord, the relatively small number of neurons receiving input from the lower airways, the extensive convergent input from the skin and other thoracic viscera, and the pattern of responses. In addition, both stimulus-induced responses and spontaneous activity are subject to modulation from supraspinal sites. On the basis of responses to inhaled irritants after either spinal cord or vagus nerve block/transection, these T2-4 spinal neurons are likely to receive spinal afferent input that is modulated by vagal-brain stem input.

Upper Thoracic Spinal Cord Injury Without Vertebral Bony Lesion: A Report of Two Cases

Spine ◽  
2002 ◽  
Vol 27 (21) ◽  
pp. E467-E470 ◽  
Author(s):  
Munehisa Koizumi ◽  
Yurito Ueda ◽  
Jin Iida ◽  
Etsuhiro Matsuyama ◽  
Takafumi Yoshikawa ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Cord Injury ◽  
Bony Lesion ◽  
Upper Thoracic
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