Polarization of primary afferent terminals in the lumbar spinal cord during fictitious locomotion

1981 ◽  
Vol 12 (5) ◽  
pp. 305-311 ◽  
Author(s):  
K. V. Baev
Keyword(s):  
Spinal Cord ◽  
Lumbar Spinal Cord ◽  
Primary Afferent ◽  
Fictitious Locomotion ◽  
Lumbar Spinal ◽  
Afferent Terminals

Concussive head injury producing suppression of sensory transmission within the lumbar spinal cord in cats

1985 ◽  
Vol 63 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Yoichi Katayama ◽  
James D. Glisson ◽  
Donald P. Becker ◽  
Ronald L. Hayes
Keyword(s):  
Spinal Cord ◽  
Head Injury ◽  
Dorsal Root ◽  
Lumbar Spinal Cord ◽  
Primary Afferent ◽  
Sensory Transmission ◽  
General Response ◽  
Lumbar Spinal ◽  
Dorsal Root Potentials ◽  
Root Stimulation

✓ This study examines the effects of concussive levels of a fluid-percussion head injury on sensory transmission within the lumbar spinal cord of the cat. Primary afferent depolarization (PAD) was suppressed for 2 to 5 minutes following injury, as assessed by dorsal root potentials and augmentation of antidromic dorsal root potentials, both evoked by stimulation of adjacent dorsal roots. Polysynaptic reflex discharges in ventral root potentials evoked by dorsal root stimulation were also profoundly suppressed during this same period, even when spontaneous and monosynaptic reflex discharges were facilitated. Changes in PAD produced by injury were abolished by spinal cord transection, but were not affected by midpontine transection. These findings suggest that concussive head injury can produce suppression of segmental sensory transmission by neurally mediated processes involving the bulbar brain stem. Recordings of dorsal root resting potentials, antidromic dorsal root potentials, and reductions of antidromic dorsal root potentials induced by tetanic root stimulation indicated that depressed segmental sensory function produced by injury was due to suppression of postsynaptic interneuronal transmission rather than to excitability changes in primary afferent fibers. Somatosensory cortical potentials evoked by dorsal root stimulation were profoundly depressed at the same time as segmental sensory transmission was suppressed, suggesting that suppressed segmental sensory transmission may also contribute to suppression of ascending sensory transmission. It is hypothesized that transmission failure of interneuronal systems in the initial period following insult may be a general response occurring in wide areas of the central nervous system, and not restricted to areas to which mechanical stress is directly applied. This response pattern may result from indiscriminate activation of interconnected excitatory and inhibitory elements of interneuronal systems.

scholarly journals Glucose is an adequate energy substrate for the depolarizing action of GABA and glycine in the neonatal rat spinal cord in vitro

2012 ◽  
Vol 107 (11) ◽  
pp. 3107-3115 ◽  
Author(s):  
Rémi Bos ◽  
Laurent Vinay
Keyword(s):  
Spinal Cord ◽  
Energy Supply ◽  
Reversal Potential ◽  
Neonatal Rat ◽  
Lumbar Spinal Cord ◽  
Primary Afferent ◽  
Artificial Cerebrospinal Fluid ◽  
High Concentrations ◽  
Lumbar Spinal

In vitro studies have repeatedly demonstrated that the neurotransmitters γ-aminobutyric acid (GABA) and glycine depolarize immature neurons in many areas of the CNS, including the spinal cord. This widely accepted phenomenon was recently challenged by experiments showing that the depolarizing action of GABA on neonatal hippocampus and neocortex in vitro was prevented by adding energy substrates (ES), such as the ketone body metabolite dl-β-hydroxybutyric acid (DL-BHB), lactate, or pyruvate to the artificial cerebrospinal fluid (ACSF). It was suggested that GABA-induced depolarizations in vitro might be an artifact due to inadequate energy supply when glucose is the sole energy source, consistent with the energy metabolism of neonatal rat brain being largely dependent on ESs other than glucose. Here we examined the effects of these ESs (DL-BHB, lactate, pyruvate) on inhibitory postsynaptic potentials (IPSPs) recorded from neonatal rat lumbar spinal cord motoneurons (MNs), in vitro. We report that supplementing the ACSF with physiologic concentrations of DL-BHB, lactate, or pyruvate does not alter the reversal potential of IPSPs ( EIPSP). Only high concentrations of pyruvate hyperpolarized EIPSP. In addition, the depolarizing action of GABA on primary afferent terminals was not affected by supplementing the ACSF with ES at physiologic concentrations. We conclude that depolarizing IPSPs in immature MNs and the primary afferent depolarizations are not caused by inadequate energy supply. Glucose at its standard concentration appears to be an adequate ES for the neonatal spinal cord in vitro.

ATP P2× Receptors and Sensory Synaptic Transmission Between Primary Afferent Fibers and Spinal Dorsal Horn Neurons in Rats

1998 ◽  
Vol 80 (6) ◽  
pp. 3356-3360 ◽  
Author(s):  
Ping Li ◽  
Amelita A. Calejesan ◽  
Min Zhuo
Keyword(s):  
Spinal Cord ◽  
Synaptic Transmission ◽  
Dorsal Horn ◽  
Lumbar Spinal Cord ◽  
Superficial Dorsal Horn ◽  
Primary Afferent ◽  
Dorsal Horn Neurons ◽  
Afferent Fibers ◽  
Primary Afferent Fibers ◽  
Lumbar Spinal

Li, Ping, Amelita A. Calean, and Min Zhuo. ATP P2× receptors and sensory synaptic transmission between primary afferent fibers and spinal dorsal horn neurons in rats. J. Neurophysiol. 80: 3356–3360, 1998. Glutamate is a major fast transmitter between primary afferent fibers and dorsal horn neurons in the spinal cord. Recent evidence indicates that ATP acts as another fast transmitter at the rat cervical spinal cord and is proposed to serve as a transmitter for nociception and pain. Sensory synaptic transmission between dorsal root afferent fibers and neurons in the superficial dorsal horn of the lumbar spinal cord were examined by whole cell patch-clamp recording techniques. Experiments were designed to test if ATP could serve as a transmitter at the lumbar spinal cord. Monosynaptic excitatory postsynaptic currents (EPSCs) were completely abolished after the blockade of both glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate and N-methyl-d-aspartate receptors. No residual current was detected, indicating that glutamate but not ATP is a fast transmitter at the dorsal horn of the lumbar spinal cord. Pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonic acid (PPADS), a selective P2× receptor antagonist, produced an inhibitory modulatory effect on fast EPSCs and altered responses to paired-pulse stimulation, suggesting the involvement of a presynaptic mechanism. Intrathecal administration of PPADS did not produce any antinociceptive effect in two different types of behavioral nociceptive tests. The present results suggest that ATP P2×2 receptors modulate excitatory synaptic transmission in the superficial dorsal horn of the lumbar spinal cord by a presynaptic mechanism, and such a mechanism does not play an important role in behavioral responses to noxious heating. The involvement of other P2× subtype receptors, which is are less sensitive to PPADS, in acute nociceptive modulation and persistent pain remains to be investigated.

Lipomeningocele associated with diplomyelia in a dog

2018 ◽  
Vol 46 (05) ◽  
pp. 323-329 ◽  
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.

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