Dorsal Cord Research Articles

18F FDG PET-CT in the Diagnosis of Spinal Cord Involvement Secondary to Non Hodgkins Lymphoma– A Case Report

<p>Spinal cord involvement secondary to non Hodgkin lymphoma (NHL) is rare and associated with quick development of neurological defects. The overall risk of central nervous system relapse in aggressive NHL ranges 2%–27% and is associated with a poor prognosis. Hence early detection is important for staging and prognostication. Magnetic Resonance Imaging (MRI) is the routinely used potential imaging modality for spinal cord metastasis. Several studies have shown the values of 18F FDG (flurodeoxyglucose) PET- CT for staging, restaging, and therapy monitoring in NHL. PET has 96% sensitivity in the detection spinal metastasis. This reported case was a 35 years old male, diagnosed as peripheral T cell lymphoma on June 2014 and was treated with chemotherapy. In January 2016 he developed swelling of lower limbs and paraparesis with bladder and bowel involvement. Duplex color Doppler of lower limbs showed normal flow and Complement Fixation Test for filariasis was negative. MRI T2W showed hyper intensity signal extending from lower cervical to all dorsal cord. The 18F FDG PET-CT was performed to restage the disease and showed intense FDG uptake in the spinal cord, extended from the lower cervical to 11<sup>th</sup> thoracic and at the level of 3<sup>rd</sup> and 4<sup>th</sup> lumbar vertebrae. The spinal cord hypermetabolism observed on PET CT scan correlated with MRI characteristics and significantly aided in the diagnosis of spinal cord involvement. This case is reported to emphasize the usefulness 18F FDG PET-CT in restaging and follow-up of patients with NHL. PET-CT imaging can reliably identify hyper-metabolic central nervous system involvement and help not only to restage patients but also to guide new therapeutic strategies.</p><p>Bangladesh J. Nuclear Med. 19(2): 146-148, July 2016</p>

MACROANATOMICAL ASPECTS OF BRACHIAL PLEXUS AND ITS BRANCHES IN THE INDIGENOUS DUCK

The injury to the peripheral nervous system is common clinical problem especially injury to the wing is the most common in birds. The present study aimed to document the detailed features of the morphological structure and the innervations areas of the brachial plexus in indigenous duck (Anas platyrhynchos domesticus). A total of six mature indigenous ducks (three of them were male and three were female) were used in this study. After administering an anesthetic to the birds, the body cavities were opened. The birds were fixed with formaldehyde after draining of the blood. The nerves of the brachial plexus were dissected separately and photographed. The brachial plexus was formed by the union of the ventral branches of 14thand 15th cervical spinal nerve and 1st, 2nd and 3rd thoracic spinal nerves, which were confirmed by palpation and counting the cervical vertebrae. Present study revealed that few small and large branches originated from brachial plexus and innervated into the specific muscles and their adjacent structure. Five nerve roots formed three nerve trunks in the duck, which constitute the dorsal and ventral cords. The pectoral trunk and median-ulnar nerve originated from ventral cord, while dorsal cord gives axillary nerve continued as a radial nerve into the wing of duck. The axillary nerve innervated into to skin of the dorsal side of the wing and shoulder deltoideous muscles, coracobrachialis muscles and propatagiasis cervical muscles. The radial nerve innervated to the humuro-brachial and triceps muscles, extensor carpi radial and supinator muscles. The ulnar nerve innervated extensor aspect of joint, flexor carpi ulnar muscles and superficial flexor muscle. The median nerve innervated into the median surface of the brachial and metacarpal region, flexor carpi radial muscle, pronator teres muscles, superficial and profound digital flexor muscles. The general macroanatomical shape of the brachial plexus and the distribution of the nerves originating from this plexus displayed some differences from other birds.

The ENU-3 protein family members function in the Wnt pathway parallel to UNC-6/Netrin to promote motor neuron axon outgrowth in C. elegans

The axons of the DA and DB classes of motor neurons fail to reach the dorsal cord in the absence of the guidance cue UNC-6/Netrin or its receptor UNC-5 in C. elegans. However, the axonal processes usually exit their cell bodies in the ventral cord in the absence of both molecules. Strains lacking functional versions of UNC-6 or UNC-5 have a low level of DA and DB motor neuron axon outgrowth defects. We found that mutations in the genes for all six of the ENU-3 proteins function to enhance the outgrowth defects of the DA and DB axons in strains lacking either UNC-6 or UNC-5. A mutation in the gene for the MIG-14/Wntless protein also enhances defects in a strain lacking either UNC-5 or UNC-6, suggesting that the ENU-3 and Wnt pathways function parallel to the Netrin pathway in directing motor neuron axon outgrowth. Our evidence suggests that the ENU-3 proteins are novel members of the Wnt pathway in nematodes. Five of the six members of the ENU-3 family are predicted to be single-pass trans-membrane proteins. The expression pattern of ENU-3.1 was consistent with plasma membrane localization. One family member, ENU-3.6, lacks the predicted signal peptide and the membrane-spanning domain. In HeLa cells ENU-3.6 had a cytoplasmic localization and caused actin dependent processes to appear. We conclude that the ENU-3 family proteins function in a pathway parallel to the UNC-6/Netrin pathway for motor neuron axon outgrowth, most likely in the Wnt pathway.

Editor's Highlight: Formulation and Toxicology Evaluation of the Intrathecal AYX1 DNA-Decoy in Sprague Dawley Rats.

The longevity of pain after surgery is debilitating and limits the recovery of patients. AYX1 is a double-stranded, unprotected, 23 base-pair oligonucleotide designed to reduce acute post-surgical pain and prevent its chronification with a single intrathecal perioperative dose. AYX1 mimics the DNA sequence normally bound by EGR1 on chromosomes, a transcription factor transiently induced in the dorsal root ganglia-spinal cord network following a noxious input. AYX1 binds to EGR1 and prevents it from launching waves of gene regulation that are necessary to maintain pain over time. A formulation suitable for an intrathecal injection of AYX1 was developed, including a specific ratio of AYX1 and calcium so the ionic homeostasis of the cerebrospinal fluid is maintained and no impact on neuromuscular control is produced upon injection. A GLP toxicology study in naïve Sprague Dawley rats was conducted using 3 dose levels up to the maximum feasible dose. Clinical observations, neurobehavioral observations, clinical pathology and histopathology of the nervous system and peripheral tissues were conducted. An additional nonGLP study was conducted in the spared nerve injury model of chronic neuropathic pain in which EGR1 is induced in the dorsal root ganglia and spinal cord. Similar testing was performed, including a modified Irwin test to assess a potential impact of AYX1 on autonomic nervous system responses, locomotion, activity, arousal, sensorimotor, and neuromuscular function. No AYX1-related adverse events were observed in any of the studies and the no-observed-adverse-effect-level was judged to be the maximum feasible dose.

Polyethylene glycol-induced motor recovery after total spinal transection in rats.

Despite more than a century of research, spinal paralysis remains untreatable via biological means. A new understanding of spinal cord physiology and the introduction of membrane fusogens have provided new hope that a biological cure may soon become available. However, proof is needed from adequately powered animal studies. Two groups of rats (n=9, study group, n=6 controls) were submitted to complete transection of the dorsal cord at T10. The animals were randomized to receive either saline or polyethylene glycol (PEG) in situ. After 4weeks, the treated group had recovered ambulation vs none in the control group (BBB scores; P=.0145). One control died. All animals were studied with somatosensory-evoked potentials (SSEP) and diffusion tensor imaging (DTI). SSEP recovered postoperatively only in PEG-treated rats. At study end, DTI showed disappearance of the transection gap in the treated animals vs an enduring gap in controls (fractional anisotropy/FA at level: P=.0008). We show for the first time in an adequately powered study that the paralysis attendant to a complete transection of the spinal cord can be reversed. This opens the path to a severance-reapposition cure of spinal paralysis, in which the injured segment is excised and the two stumps approximated after vertebrectomy/diskectomies.

Temporal and spatial dynamics of peripheral afferent-evoked activity in the dorsal horn recorded in rat spinal cord slices.

In the present study, multi-electrode array recording was used to examine dorsal horn activity following stimulation of primary afferents in a rat dorsal root attached-spinal cord slice preparation. The multi-electrode array probe was placed under the dorsal horn slice and local field potentials evoked by stimulation on the dorsal root were analyzed. Three kinds of dorsal root-evoked responses were identified. In lamina IIo, local field potentials exhibited P1 (peak latency 1.46±0.08ms), N1 (2.77±0.18ms, n=12), N2 (7.31±0.48ms), N3 (12.12±0.73ms) and P2(18.30±0.80ms) waves. In lamina IIi local field potentials exhibited P (1.99±0.10ms), N1 (3.35±0.17ms) and N2 (8.58±0.44ms) waves. In laminae III-VI, local field potentials exhibited P1 (3.01±0.07ms), P2 (7.02±0.21ms) and N waves (22.57±0.79ms). Sweep spread was calculated by two dimensional current source density (2D-CSD) analysis. Both α-amino-3-hydroxy-5-methylisoxazole-4-propionic a/kainate and N-methyl-d-aspartate-type glutamate receptors participated in this neuronal circuitry. Morphine diminished local field potentials. Gabapentin diminished the negative components in lamina II and P2 component in lamina IIo, but increased the positive components in lamina IIi and laminae III-VI. The present study revealed that functional dorsal horn activity was preserved in the spinal cord slice preparation. Glutamatergic synapses were crucially involved in information processing. Opioid interneurons and gabapentin may play a modulatory role in regulating signal flows in the dorsal horn. Taken together, these results identify a spatio-temporal profile of dorsal horn activity evoked by dorsal root stimulation, and implicate glutamatergic and opioidergic receptors and gabapentin in this activity.

Keeping amphioxus in the laboratory: an update on available husbandry methods

Cephalochordates, commonly known as amphioxus or lancelets, are small, marine animals that can be found in coastal habitats of temperate, subtropical, and tropical waters. Together with vertebrates and tunicates, the cephalochordates belong to the chordate phylum, whose members are characterized by a number of conserved morphological features, such as a dorsal nerve cord, a notochord, a pharynx, a segmented musculature as well as a post-anal tail. Due to their basal position within the phylum, cephalochordates have become essential models for studying the evolutionary origin and diversification of vertebrates. Here, we present the currently available methods for maintaining and rearing cephalochordates in a laboratory environment, focusing on five species: the European amphioxus (Branchiostoma lanceolatum), the Florida amphioxus (Branchiostoma floridae), the Chinese amphioxus (Branchiostoma belcheri), the Japanese amphioxus (Branchiostoma japonicum), and the Bahamas lancelet (Asymmetron lucayanum). In addition to reviewing the protocols for capture, transport, aquaculture, and feeding of adults, we discuss methods for controlling gonad development and spawning, as well as for growing embryos and larvae. This information is complemented by observations from our animal facility on the European amphioxus (Branchiostoma lanceolatum). In sum, this work summarizes the latest advances in cephalochordate animal husbandry and highlights challenges for improving the use of these animals as laboratory model systems.

T-Box Genes and Developmental Gene Regulatory Networks in Ascidians.

Ascidians are invertebrate chordates with a biphasic life cycle characterized by a dual body plan that displays simplified versions of chordate structures, such as a premetamorphic 40-cell notochord topped by a dorsal nerve cord and postmetamorphic pharyngeal slits. These relatively simple chordates are characterized by rapid development, compact genomes and ease of transgenesis, and thus provide the opportunity to rapidly characterize the genomic organization, developmental function, and transcriptional regulation of evolutionarily conserved gene families. This review summarizes the current knowledge on members of the T-box family of transcription factors in Ciona and other ascidians. In both chordate and nonchordate animals, these genes control a variety of morphogenetic processes, and their mutations are responsible for malformations and developmental defects in organisms ranging from flies to humans. In ascidians, T-box transcription factors are required for the formation and specialization of essential structures, including notochord, muscle, heart, and differentiated neurons. In recent years, the experimental advantages offered by ascidian embryos have allowed the rapid accumulation of a wealth of information on the molecular mechanisms that regulate the expression of T-box genes. These studies have also elucidated the strategies employed by these transcription factors to orchestrate the appropriate spatial and temporal deployment of the numerous target genes that they control.

Neural Stem Cells Transplantation as a Neuroprotective Strategy for Amyotrophic Lateral Sclerosis (ALS)

Introduction Amiotrophic lateral sclerosis (ALS) is a neurodegenerative disease with a prevalence rate of up to 7.4/100,000 and the overall risk of developing ALS over a lifetime is 1:400. Most patients die from respiratory failure following a course of progressive weakness. There is no effective therapy. Novel therapeutic strategies might be directed at replacing or repairing the damaged motor neurons; Cell therapy is emerging as a potential therapeutic option in ALS. The primary objective of our study was to verify the safety and tolerability of transplantation of human fetal neural stem cells (hNSCs) directly into the spinal cord of humans. The study was approved by the SuperiorNational Health Institute. Material and Methods 18 patients with definite ALS were recruited and treated. Patients were included if they had ALS of spinal onset with severe functional impairment of the lower limbs and mild functional impairment of the upper limbs without signs of respiratory failure. The patients were monitored by clinical evaluation which included the ALS-FRS scale, Norris score, bulbar score, and MRC strength scale. Respiratory assessment included clinical evaluation, pulmonary function tests, arterial blood gases analysis, and nocturnal cardio-respiratory monitoring. Neurophysiological assessments were made including EMG, and somatosensory evoked potentials. The neuroradiological assessment consisted of MRI of spinal cord and brain before and after Gadolinium DTA infusion. A clinical psychologist performed psychological evaluation including an interview and psychological tests. Human fetal brain tissue specimens, all derived from the forebrain, were routinely collected from fetuses at gestational ages greater than the 8th post-conceptional week. They were immediately dissected and used to generate hNSC lines under sterile conditions. Dissociation of brain tissue, primary culturing and cell propagation were performed according to the procedure described previously by Vescovi and colleagues. Six patients received hNSCs microinjections into the dorsal (T7-T9) cord tract (3 of them received unilateral hNSCs microinjection while the remaining ones received bilateral microinjections); the other twelve patients received hNSCs microinjections into the cervical (C5-C6) cord tract (3 of them received unilateral hNSCs microinjection while the remaining ones received bilateral microinjections). Results No patients manifested severe adverse events such as death, respiratory failure or permanent post-surgical neurological deficits. Minor adverse events were: intercostal pain (2 patients) which was reversible after a mean period of 3 days after surgery, arm and leg sensory dysesthesia (6 patients) which was reversible after a mean period of 6 weeks after surgery. No patient manifested bladder and bowel dysfunction, or arm and leg motor deficit. All patients showed a good acceptance of the procedure and no significant modifications of the psychological status or quality of life were observed. Conclusions Our results appear to demonstrate that the procedures of fetal stem cells transplantation into the spinal cord of humans are safe and well tolerated by ALS patients. The minimal side effects and the absence of detrimental effects on neurological function support further research in stem cell transplantation in carefully monitored patients with ALS.

Discriminating long myelitis of neuromyelitis optica from sarcoidosis.

To compare longitudinally extensive myelitis in neuromyelitis optica spectrum disorders (NMOSD) and spinal cord sarcoidosis (SCS). We identified adult patients evaluated between 1996 and 2015 with SCS or NMOSD whose first myelitis episode was accompanied by a spinal cord lesion spanning ≥3 vertebral segments. All NMOSD patients were positive for aquaporin-4-immunoglobulin G, and all sarcoidosis cases were pathologically confirmed. Clinical characteristics were evaluated. Spine magnetic resonance imaging was reviewed by 2 neuroradiologists. We studied 71 patients (NMOSD, 37; SCS, 34). Sixteen (47%) SCS cases were initially diagnosed as NMOSD or idiopathic transverse myelitis. Median delay to diagnosis was longer for SCS than NMOSD (5 vs 1.5 months, p < 0.01). NMOSD myelitis patients were more commonly women, had concurrent or prior optic neuritis or intractable vomiting episodes more frequently, had shorter time to maximum deficit, and had systemic autoimmunity more often than SCS (p < 0.05). SCS patients had constitutional symptoms, cerebrospinal fluid (CSF) pleocytosis, and hilar adenopathy more frequently than NMOSD (p < 0.05); CSF hypoglycorrhachia (11%, p = 0.25) and elevated angiotensin-converting enzyme (18%, p = 0.30) were exclusive to SCS. Dorsal cord subpial gadolinium enhancement extending ≥2 vertebral segments and persistent enhancement >2 months favored SCS, and ringlike enhancement favored NMOSD (p < 0.05). Maximum disability was similar in both disorders. SCS is an under-recognized cause of longitudinally extensive myelitis that commonly mimics NMOSD. We identified clinical, laboratory, systemic, and radiologic features that, taken together, help discriminate SCS from NMOSD.

Metamorphosis and definitive organogenesis in the holothurian Apostichopus japonicus

The structure of the late doliolaria, pentactula and 1-month-old juvenile of the holothurian Apostichopus japonicus was studied using light microscopy and 3D reconstruction methods. It was shown that metamorphosis in this species consists in the reorganization of the shape of the body and the destruction of provisional organs. The late doliolaria has a spindle-like form, ciliary rings and hyaline spheres shifted relative to the anterior-posterior axis of the body. Some provisional organs (ciliary rings, hyaline spheres) are destroyed during settlement, and others (hydropore and hydroporic canal) remain after metamorphosis. Definitive organogenesis in A. japonicus begins long before metamorphosis. The late doliolaria already has well-developed water-vascular and digestive systems, and the ectoneural part of the nervous system. Muscle and hemal systems begin to form in the pentactula. Moreover, the calcareous ring and connective tissue part of the body wall develop at this stage. The pentactula has anlages of the hyponeural part of the nervous system, which form in the mid-ventral and dorsal nerve cords. The hemal ring of the pentactula is located on the inner wall of the water-vascular ring. It remains unclosed in the left ventral radius. One-month-old juveniles have all the major organ systems except respiratory and reproductive systems. The hemal vessels of the intestine are well developed and begin to form the rete mirabile. Differentiation of the intestine into regions due to differential specialization of the enterocytes begins in 1-month-old juveniles. Obviously, emergence of new types of enterocytes enables the animal to consume a wider range of food items and indicates its increased feeding activity.

Downregulation of Cdh1 signalling in spinal dorsal horn contributes to the maintenance of mechanical allodynia after nerve injury in rats.

BackgroundAnaphase-promoting complex/cyclosome (APC/C) and its co-activator Cdh1 are important ubiquitin-ligases in proliferating cells and terminally differentiated neurons. In recent years, APC/C-Cdh1 has been reported as an important complex contributing to synaptic development and transmission. Interestingly, cortical APC/C-Cdh1 is found to play a critical role in the maintenance of neuropathic pain, but it is not clear whether APC/C-Cdh1 in spinal dorsal cord is involved in molecular mechanisms of neuropathic pain conditions.ResultsImmunostaining showed that Cdh1 was mainly distributed in dorsal horn neurons of the spinal cord in rats. Its expression was downregulated in the ipsilateral dorsal horn at 14 days after spared nerve injury. Rescued expression of Cdh1 in spinal cord by intrathecal administration of recombinant lentivirus encoding Cdh1 (Lenti-Cdh1-GFP) significantly attenuated spared nerve injury-induced mechanical allodynia. Furthermore, rescued expression of spinal Cdh1 significantly reduced surface membrane expression of GluR1, but increased the expression of GluR1-related erythropoietin-producing human hepatocellular receptor A4 and its ligand EphrinA1 in dorsal horn of spared nerve injury-treated animals.ConclusionsThis study indicates that a downregulation of Cdh1 expression in spinal dorsal horn is involved in molecular mechanisms underlying the maintenance of neuropathic pain. Upregulation of spinal Cdh1 may be a promising approach to treat neuropathic pain.

Central neuromechanisms underlying control of intragastric pressure through acupuncture at Zusanli (ST36) in rats: the upper cervical cord is the key link between the ascending and descending pathways.

Sensory inputs stimulated by Zusanli (ST36) acupuncture in the abdomen are known to converge in the upper cervical cord. However, it is unclear whether these inputs are subsequently conveyed to the hypothalamic paraventricular nucleus and what kind of afferent fibers are involved. We focused on the upper cervical cord, where afferent inputs converge, and detected c-fos expression in oxytocinergic neurons. We found that Zusanli acupuncture therapy effectively elevated intragastric pressure, but inhibited expression of c-fos in oxytocinergic neurons of the paraventricular nucleus in upper cervical cord injured rats. These Zusanli acupuncture effects remained even after complete dorsal cord transection. However, after complete transection of the spinal cord or dorsolateral funiculus, the effects were significantly attenuated and even disappeared. These findings suggest that the paraventricular nucleus is responsible for pooling and integrating signals from the Zusanli acupuncture and sensory information from the intragastric pressure variation, thereby contributing to the regulation of intragastric pressure. The upper cervical cord serves as the key link between ascending and descending pathways, which conveys afferent inputs to the paraventricular nucleus through the dorsolateral funiculus.

Transpedicular Surgical Decompression of Dorsal Spinal Tuberculosis (Pott’s Disease) with Vertebral Collapse without Fixation

Introduction: Spinal tuberculosis is prevalent in developing countries. Advancements in technique and technology has improved the outcome, but cost of the newer prosthetic implants and insufficient public healthcare infrastructure in third world countries pose difficulty in surgical treatment of many of these patients. Methods: Twenty two patients of dorsal Pott’s disease having anterior or anterolateral compressionswith significantneurologicaldeficitswereprospectively studied in five years period (2010 to 2015) and were subjected to unilateral transpedicular decompression of the dorsal cord with maximal preservation of bony elements including ribs without fixation by prosthetic implants. Patients were advised absolute bed rest for 3 months after surgery. Results: Study group included 12 males and 10 females of with average age 37.5 years (range 14 to 68 years). Clinical improvement was observed in all but one patient, who showed recovery in the follow up. Three patients had recurrence with neurological deterioration due to discontinued antitubercular chemotherapy and required second surgery leading to clinical recovery. There was no increase in kyphosis in follow up in any patient. Conclusion: Unilateral transpedicular decompression with bed rest for three months appear an option in selected patients of dorsal Pott’s disease with anterior/ anterio-lateral compression with significant neurological deficit.

Presynaptic and postsynaptic regulation of muscle contractions in the ascarid nematodeAscaris suum: a target for drug action

The aim of this study was to determine the role in contractions of postsynaptic nicotinic acetylcholine (nACh) and γ-aminobutyric acid (GABA) receptors, in the bag region of Ascaris suum muscle cells, as well as the role of synaptic receptors between interneurons and motor neurons in the dorsal and ventral nerve cord. We have measured the isometric contractions of isolated segments of A. suum, with or without the nerve cord (dorsal or ventral). Contractions were caused by increasing concentrations of ACh or by electrical field stimulation (EFS). Based on our results, the presence of the nerve cord is essential for the contractile effects of ACh. The EC50 value of ACh for innervated muscle strips was 10.88μm. Unlike intact (innervated) preparations, there was no contraction of the muscle flaps when the nerve cord was mechanically removed. Furthermore, continuous EFS produced stable contractions of innervated muscle strips, but they are not sensitive to mecamylamine (100μm). However, GABA (30μm) significantly inhibited the EFS-induced contractions. EFS with the same characteristics did not cause muscle contractions of denervated muscle strips, but EFS with a wider pulse induced the increasing of tone and irregular contractions. These contractions were completely insensitive to the effect of GABA. The EC50 for ACh did not differ between the dorsal and ventral segments (9.83μm and 9.45μm), while GABA exhibited features of competitive and non-competitive antagonists, regardless of whether it acted on the dorsal or ventral segments of A. suum. It is obvious that drugs will be more effective if they act on both the synaptic and extrasynaptic nACh and GABA receptors.

Transcriptional Control of Synaptic Remodeling through Regulated Expression of an Immunoglobulin Superfamily Protein

Neural circuits are actively remodeled during brain development, but the molecular mechanisms that trigger circuit refinement are poorly understood. Here, we describe a transcriptional program in C.elegans that regulates expression of an Ig domain protein, OIG-1, to control the timing of synaptic remodeling. DD GABAergic neurons reverse polarity during larval development by exchanging the locations of pre- and postsynaptic components. In newly born larvae, DDs receive cholinergic inputs in the dorsal nerve cord. These inputs are switched to the ventral side by the end of the first larval (L1) stage. VD class GABAergic neurons are generated in the late L1 and are postsynaptic to cholinergic neurons in the dorsal nerve cord but do not remodel. We investigated remodeling of the postsynaptic apparatus in DD and VD neurons using targeted expression of the acetylcholine receptor (AChR) subunit, ACR-12::GFP. We determined that OIG-1 antagonizes the relocation of ACR-12 from the dorsal side in L1 DD neurons. During the L1/L2 transition, OIG-1 is downregulated in DD neurons by the transcription factor IRX-1/Iroquois, allowing the repositioning of synaptic inputs to the ventral side. In VD class neurons, which normally do not remodel, the transcription factor UNC-55/COUP-TF turns off IRX-1, thus maintaining high levels of OIG-1 to block the removal of dorsally located ACR-12 receptors. OIG-1 is secreted from GABA neurons, but its anti-plasticity function is cell autonomous and may not require secretion. Our study provides a novel mechanism by which synaptic remodeling is set in motion through regulated expression of an Ig domain protein.

FORMAÇÃO E DISTRIBUIÇÃO DO PLEXO BRAQUIAL EM PAPAGAIOS VERDADEIROS (&lt;italic&gt;Amazona aestiva, Linnaeus, 1758&lt;/italic&gt;)

&lt;title&gt;Resumo&lt;/title&gt;&lt;p&gt;Procedimentos anestésicos locais são realizados comumente em aves domésticas e silvestres, por ser de baixo custo e de rápida indução, desde que feitos com precisão, o que requer conhecimento anatômico específico da área a ser operada. Este trabalho objetivou estabelecer a origem e a distribuição do plexo braquial do papagaio verdadeiro (&lt;italic&gt;Amazona aestiva&lt;/italic&gt;), através da dissecação da pele e da musculatura de 22 papagaios (17 machos e 5 fêmeas), provenientes do Centro de Triagem de Animais Silvestres do Distrito Federal, após óbito motivado por causas naturais, promovendo o isolamento das raízes formadoras do plexo braquial, bem como de sua ramificação. O plexo braquial foi formado através de quatro troncos, envolvendo os ramos ventrais dos segmentos medulares de C9 a C10, C10 a C11, C11 a T1 e T1 a T2, que se uniram em um curto tronco comum, ramificado em cordões dorsal e ventral. O tronco comum emitiu os delgados nervos subcoracóide e subescapular, além do ramo para o músculo escapuloumeral. O cordão dorsal deu origem aos nervos anconeal, axilar e radial, e o cordão ventral, os nervos peitoral cranial, peitoral caudal, coracobraquial e medianoulnar, cujos ramos supriram os músculos dos compartimentos extensor e flexor do membro torácico, músculos peitorais e pele sobrejacente.&lt;/p&gt;

Gentle Mechanical Skin Stimulation Inhibits Micturition Contractions via the Spinal Opioidergic System and by Decreasing Both Ascending and Descending Transmissions of the Micturition Reflex in the Spinal Cord.

Recently, we found that gentle mechanical skin stimulation inhibits the micturition reflex in anesthetized rats. However, the central mechanisms underlying this inhibition have not been determined. This study aimed to clarify the central neural mechanisms underlying this inhibitory effect. In urethane-anesthetized rats, cutaneous stimuli were applied for 1 min to the skin of the perineum using an elastic polymer roller with a smooth, soft surface. Inhibition of rhythmic micturition contractions by perineal stimulation was abolished by naloxone, an antagonist of opioidergic receptors, administered into the intrathecal space of the lumbosacral spinal cord at doses of 2–20 μg but was not affected by the same doses of naloxone administered into the subarachnoid space of the cisterna magna. Next, we examined whether perineal rolling stimulation inhibited the descending and ascending limbs of the micturition reflex. Perineal rolling stimulation inhibited bladder contractions induced by electrical stimulation of the pontine micturition center (PMC) or the descending tract of the micturition reflex pathway. It also inhibited the bladder distension-induced increase in the blood flow of the dorsal cord at L5–S1, reflecting the neural activity of this area, as well as pelvic afferent-evoked field potentials in the dorsal commissure at the lumbosacral level; these areas contain long ascending neurons to the PMC. Neuronal activities in this center were also inhibited by the rolling stimulation. These results suggest that the perineal rolling stimulation activates the spinal opioidergic system and inhibits both ascending and descending transmissions of the micturition reflex pathway in the spinal cord. These inhibitions would lead to the shutting down of positive feedback between the bladder and the PMC, resulting in inhibition of the micturition reflex. Based on the central neural mechanisms we show here, gentle perineal stimulation may be applicable to several different types of overactive bladder.

FORMAÇÃO E DISTRIBUIÇÃO DO PLEXO BRAQUIAL EM PAPAGAIOS VERDADEIROS ( Amazona aestiva, Linnaeus, 1758 )

Local anesthetic procedures are commonly used in domestic and wild birds, because of its low cost and fast induction, as long as applied with great precision, which requires specific anatomical knowledge of the site of incision. This study aimed to establish the origin and distribution of the brachial plexus of the Blue-fronted Parrot (Amazona aestiva) by anatomic dissection of the skin and musculature of 22 specimens (17 males and 5 females) from the Wild Animals Screening Center of the Federal District after death by natural causes. The dissection work promoted the isolation of the forming roots of the brachial plexus, as well as its ramifications. The brachial plexus was formed by four trunks, including the ventral spinal cord rami segments from C9 to C10, C10 to C11, C11 to T1 and T1 to T2, which joined into a short common trunk, branched into dorsal and ventral cords. The thin nerves subcoracoideus and subscapularis and the branch to the scapulohumeralis muscle originated from the common trunk. The dorsal cord originated the anconeal, axillaris and radialis nerves, while the ventral cord gave origin for the pectoralis cranialis, pectoralis caudalis, coracobrachialis and medianoulnaris. These branches innervated the muscles of the extensor and flexor compartments of the forelimb, pectoral muscles and overlying skin. Keywords: birds; innervation; peripheral nervous system; psittaciformes; wing.

Staggered multi-site low-frequency electrostimulation effectively induces locomotor patterns in the isolated rat spinal cord.

Experimental animal study. Epidural stimulation has been used to activate locomotor patterns after spinal injury and typically employs synchronous trains of high-frequency stimuli delivered directly to the dorsal cord, thereby recruiting multiple afferent nerve roots. Here we investigate how spinal locomotor networks integrate multi-site afferent input and address whether frequency coding is more important than amplitude to activate locomotor patterns. Italy and Belgium. To investigate the importance of input intensity and frequency in eliciting locomotor activity, we used isolated neonatal rat spinal cords to record episodes of fictive locomotion (FL) induced by electrical stimulation of single and multiple dorsal roots (DRs), employing different stimulating protocols. FL was efficiently induced through staggered delivery (delays 0.5 to 2 s) of low-frequency pulse trains (0.33 and 0.67 Hz) to three DRs at intensities sufficient to activate ventral root reflexes. Delivery of the same trains to a single DR or synchronously to multiple DRs remained ineffective. Multi-site staggered trains were more efficient than randomized pulse delivery. Weak trains simultaneously delivered to DRs failed to elicit FL. Locomotor rhythm resetting occurred with single pulses applied to various distant DRs. Electrical stimulation recruited spinal networks that generate locomotor programs when pulses were delivered to multiple sites at low frequency. This finding might help devising new protocols to optimize the increasingly more common use of epidural implantable arrays to treat spinal dysfunctions.