The Effect of Cauda Equina Constriction on Nitric Oxide Synthase Activity

Nitric oxide synthase (NOS) activity was studied in the gray and white matter regions of the spinal cord 2 and 5 days after multiple cauda equina constrictions of the central processes of L7-Co5 dorsal root ganglia neurons. The results show considerable differences in enzyme activity in the thoracic, upper lumbar, lower lumbar, and sacral segments. Increased NOS activity was observed at 2 days after multiple cauda equina constrictions in the dorsal, lateral, and ventral columns of the lower lumbar segments and in the ventral column of the upper lumbar segments. The values returned to control levels within 5 postconstriction days. In the lateral columns of thoracic segments taken 2 and 5 days after surgery, NOS activity was enhanced by 54% and 55% and in the upper lumbar segments by 130% and 163%, respectively. Multiple cauda equina constrictions performed surgically for 2 and 5 days caused a significant increase in NOS activity predominantly in the gray matter regions of thoracic segments. A quite different response was found 5 days postconstriction in the upper lumbar segments, where the enzyme activity was significantly decreased in the dorsal horn, intermediate zone, and ventral horn. No such extreme differences could be seen in the lower lumbar segments, where NOS activity was significantly enhanced only in the ventral horn. The data correspond with a higher number of NOS immunoreactive somata, quantitatively evaluated in the ventral horn of the lower lumbar segments at 5 days after multiple cauda equina constrictions. While the great region-dependent heterogeneity in NOS activity seen 2 and 5 days after multiple cauda equina constrictions is quite apparent and suggestive of an active role played by nitric oxide in neuroprotective or neurotoxic processes occurring in the gray and white matter of the spinal cord, the extent of damage or the degree of neuroprotection caused by nitric oxide in compartmentalized gray and white matter in this experimental paradigm would be possible only using longer postconstriction periods.     

Membrane lipids of human peripheral nerve and spinal cord.

Major membrane lipids were determined in specimens of human peripheral nerve (cauda equina) and spinal cord of 10 subjects aged 20-70 years. The same lipids were also assayed in myelin from the same tissues isolated with two different procedures and in myelin of cauda equina from 3 subjects aged 17-91 years isolated with a third method. The concentrations (mean and standard deviation) of phospholipids were 90 +/- 11 and 96 +/- 9 nmol/g fresh weight; of cholesterol 70 +/- 15 and 101 +/- 16; of cerebroside 19 +/- 3 and 41 +/- 7; of sulfatide 10 +/- 1 and 11 +/- l; and of gangliosides 0.80 +/- 0.08 and 0.40 +/- 0.05 N in cauda equina and spinal cord, respectively. The proportion of ethanolamine phosphoglyceride was lower and that of sphingomyelin higher in cauda equina than in spinal cord. The myelin of peripheral nerve and spinal cord contained almost the same proportions of lipids as the whole tissue. The protein-bound sialic acid content was 3-fold higher than the lipid-bound sialic acid content in cauda myelin. The fatty acid patterns of choline, ethanolamine, inositol and serine phosphoglycerides of spinal cord and its myelin, were very similar to those of cerebral white matter, while the phosphoglycerides of cauda equina had higher proportions of monoenoic acids and lower proportions of polyunsaturated fatty acids. The fatty acid patterns of sphingomyelin, cerebroside and sulfatide of spinal cord were similar to those of cerebral white matter, while those of cauda equina contained significantly more saturated fatty acids. This suggests that the lipid and fatty acid compositions of peripheral nerve are particularly suitable for the formation of a tightly packed myelin membrane which can be a powerful shield against infections and other injuries.     

The shortened spinal cord in tetraodontiform fishes

In teleosts, the spinal cord generally extends along the entire vertebral canal. The Tetraodontiformes, in which the spinal cord is greatly reduced in length with a distinct long filum terminale and cauda equina, have been regarded as an aberration. The aims of this study are: 1) to elucidate whether the spinal cord in all tetraodontiform fishes shorten with the filum terminale, and 2) to describe the gross anatomical and histological differences in the spinal cord among all families of the Tetraodontiformes. Representative species from all families of the Tetraodontiformes, and for comparison the carp as a common teleost, were investigated. In the Triacanthodidae, Triacanthidae, and Triodontidae, which are the more ancestral taxa of the Tetraodontiformes, the spinal cord extends through the entire vertebral canal. In the Triacanthidae and Triodontidae, the caudal half or more spinal segments of the spinal cord, however, lack gray matter and consist largely of nerve fibers. In the other tetraodontiform families, the spinal cord is shortened forming a filum terminale with the cauda equina, which is prolonged as far as the last vertebra. The shortened spinal cord is divided into three groups. In the Ostraciidae and Molidae, the spinal cord tapers abruptly at the cranium or first vertebra forming a cord‐like filum terminale. In the Monacanthidae, Tetraodontidae, and Diodontidae, it abruptly flattens at the rostral vertebrae forming a flat filum terminale. The spinal cord is relatively longer in the Monacanthidae than that in the other two families. It is suggested by histological features of the flat filum terminale that shortening of the spinal cord in this group progresses in order of the Monacanthidae, Tetraodontidae, and Diodontidae. In the Balistidae and Aracanidae, the cord is relatively long and then gradually decreased in dorso‐ventral thickness. J. Morphol. 276:290–300, 2015. © 2014 Wiley Periodicals, Inc.     

Alterations in growth-associated protein (GAP-43) expression in lower urinary tract pathways following chronic spinal cord injury

Alterations in the expression of growth-associated protein 43 (GAP-43) were examined in lower urinary tract micturition reflex pathways 6 or 8 weeks following complete spinal cord transection (~ T9). In control animals, expression of GAP-43 was present in specific regions of the gray matter in the rostral lumbar and caudal lumbosacral spinal cord, including: (1) the dorsal commissure; (2) the corticospinal tract; (3) the dorsal horn; and (4) the regions of the intermediolateral cell column (L1-L2) and the sacral parasympathetic nucleus (L6-S1); and (5) in the lateral collateral pathway of Lissauer in L6-S1 spinal segments. Densitometry analysis has demonstrated significant increases (p 0.001; 1.3-6.4-fold increase) in GAP-43-immunoreactivity (IR) in these regions of the rostral lumbar (L1-L2) and caudal lumbosacral (L6-S1) spinal cord 6 weeks following spinal cord injury. Changes in GAP-43-IR were restricted to the L1-L2 and L6-S1 segments that are involved in lower urinary tract reflexes. Changes in GAP-43-IR were not observed at the L5 segmental level except for an increase in GAP-43-IR in the superficial, dorsal horn at 6 weeks post-injury. In all segments examined, GAP-43-IR was decreased (2-5-fold) in the corticospinal tract (dorsal division) 6 and 8 weeks following spinal cord injury. Eight weeks following spinal cord injury, changes in GAP-43-IR had returned to control levels except for the persistence of increased GAP-43-IR in the region of the sacral parasympathetic nucleus and the lateral collateral pathway in the S1 spinal segment. Alterations in GAP-43-IR following chronic spinal cord injury may suggest a reorganization of bladder afferent projections and spinal elements involved in urinary bladder reflexes consistent with alterations in urinary bladder function (hyperreflexia) observed in animals following spinal cord injury above the lumbosacral spinal cord.     

Alterations in growth-associated protein (GAP-43) expression in lower urinary tract pathways following chronic spinal cord injury

Alterations in the expression of growth-associated protein 43 (GAP-43) were examined in lower urinary tract micturition reflex pathways 6 or 8 weeks following complete spinal cord transection (approximately T9). In control animals, expression of GAP-43 was present in specific regions of the gray matter in the rostral lumbar and caudal lumbosacral spinal cord, including: (1) the dorsal commissure; (2) the corticospinal tract; (3) the dorsal horn; and (4) the regions of the intermediolateral cell column (L1-L2) and the sacral parasympathetic nucleus (L6-S1); and (5) in the lateral collateral pathway of Lissauer in L6-S1 spinal segments. Densitometry analysis has demonstrated significant increases (p < or =0.001; 1.3-6.4-fold increase) in GAP-43-immunoreactivity (IR) in these regions of the rostral lumbar (L1-L2) and caudal lumbosacral (L6-S1) spinal cord 6 weeks following spinal cord injury. Changes in GAP-43-IR were restricted to the L1-L2 and L6-S1 segments that are involved in lower urinary tract reflexes. Changes in GAP-43-IR were not observed at the L5 segmental level except for an increase in GAP-43-IR in the superficial, dorsal horn at 6 weeks post-injury. In all segments examined, GAP-43-IR was decreased (2-5-fold) in the corticospinal tract (dorsal division) 6 and 8 weeks following spinal cord injury. Eight weeks following spinal cord injury, changes in GAP-43-IR had returned to control levels except for the persistence of increased GAP-43-IR in the region of the sacral parasympathetic nucleus and the lateral collateral pathway in the S1 spinal segment. Alterations in GAP-43-IR following chronic spinal cord injury may suggest a reorganization of bladder afferent projections and spinal elements involved in urinary bladder reflexes consistent with alterations in urinary bladder function (hyperreflexia) observed in animals following spinal cord injury above the lumbosacral spinal cord.     

Differential Distribution of Retinoic Acid Synthesis in the Chicken Embryo as Determined by Immunolocalization of the Retinoic Acid Synthetic Enzyme, RALDH-2

Retinaldehyde dehydrogenase type 2 (RALDH-2) is a major retinoic acid generating enzyme in the early embryo. Here we report the immunolocalization of this enzyme (RALDH-2-IR) in stage 6-29 chicken embryos; we also show that tissues that exhibit strong RALDH-2-IR in the embryo contain RALDH-2 and synthesize retinoic acid. RALDH-2-IR indicates dynamic and discrete patterns of retinoic acid synthesis in the embryo, particularly within the somitic mesoderm, lateral mesoderm, kidney, heart, and spinal motor neurons. Prior to somitogenesis, RALDH-2-IR is present in the paraxial mesoderm with a rostral boundary at the level of the presumptive first somite; as the somites form, they exhibit strong RALDH-2-IR. Cervical presomitic mesoderm exhibits RALDH-2-IR but thoracic presomitic mesoderm does not. Neural crest cells do not express detectable levels of RALDH-2, but migrating crest cells are associated with RALDH-2 expressing mesoderm. The developing limb mesoderm expresses little RALDH-2-IR; however, RALDH-2-IR is strongly expressed in tissues adjacent to the limb. The most lateral, earliest-projecting motor neurons at all levels of the spinal cord exhibit RALDH-2-IR. Subsequently, many additional motor neurons in the brachial and lumbar cord regions express RALDH-2-IR. Motor neuronal expression of RALDH-2-IR is present in the growing axons as they extend to the periphery, indicating a potential role of retinoic acid in nerve influences on peripheral differentiation. With the exception of a transient expression in the facial/vestibulocochlear nucleus, cranial motor neurons do not express detectable levels of RALDH-2-IR.     

HSP70 constitutive expression in rat central nervous system from postnatal development to maturity.

We studied the level of the basal (constitutive) HSP70 expression (inducible and constitutive forms) in the central nervous system (CNS) of male and female rats from the postnatal period to maturity. HSP70 levels were analyzed by immunoblotting in five different areas (cortex, hippocampus, hypothalamus, cerebellum, and spinal cord). The highest levels of HSP70 were found in juvenile rats and decreased progressively until reaching baseline levels between 2 and 4 months. A slight and nonsignificant increase in aged (2-year-old) rats compared with adult subjects was observed in some cerebral areas (cerebral cortex, hippocampus, and cerebellum). In the first weeks of postnatal development, HSP70 immunoreactivity was distributed throughout CNS sections and no specific immunopositive cells could be clearly determined. In adult animals, strong immunostaining was observed in some large neurons (Purkinje neurons and mesencephalic and spinal cord motor neurons), some perivascular and subpial astrocytes, and ependymocytes. Immunoelectron microscopy revealed that HSP70 in these cells is located in the perinuclear area and in mitochondria, rough endoplasmic reticulum, and microtubules. In neurons, strong immunolabeling was also observed in synaptic membranes. The postnatal time course of HSP70 levels and the location and size of HSP70-immunopositive cells suggest that HSP70 constitutively expressed in the rat CNS may be mainly determined by the degree of development and metabolic activity of the neural cells.     

Morphological studies of the spinal cord in tetraodontiformes fishes

The spinal cord of two tetraodontiform fishes, the Japanese file fish (Navodon modestus) and the panther puffer (Takifugu pardalis), are unusual among vertebrates in having a markedly abbreviated spinal cord with a long and flattened filum terminale. Only the rostral short part of the cord of both species is cylindrical; the greater part of the cord is markedly flat. The majority of the spinal nerve roots leave the short cylindrical part. The flattened part of the cord contains the central canal, myelinated nerve fibers, and a few motoneurons surrounding the cauda equina, and it is histologically similar to the filum terminale of amphibians and mammals. The spinal cords of other teleosts, the sun-fish and angler, also are abbreviated and possess a filum terminale and cauda equina. These orders possess an enormous head and short trunk. However, the correlation between this body form and an abbreviated cord is not causal, since the tetraodontiform species described here show ordinary body proportions. The spinal cord may be abbreviated in tetraodontiform fishes in general.     

SPARCL1-containing neurons in the human brainstem and sensory ganglion

Secreted protein, acidic and rich in cysteine-like 1 (SPARCL1) is a member of the osteonectin family of proteins. In this study, immunohistochemistry for SPARCL1 was performed to obtain its distribution in the human brainstem, cervical spinal cord, and sensory ganglion. SPARCL1-immunoreactivity was detected in neuronal cell bodies including perikarya and proximal dendrites, and the neuropil. The motor nuclei of the IIIrd, Vth, VIth, VIIth, IXth, Xth, XIth, and XIIth cranial nerves and spinal nerves contained many SPARCL1-immunoreactive (-IR) neurons with medium-sized to large cell bodies. Small and medium-sized SPARCL1-IR neurons were distributed in sensory nuclei of the Vth, VIIth, VIIIth, IXth, and Xth cranial nerves. In the medulla oblongata, the dorsal column nuclei also had small to medium-sized SPARCL1-IR neurons. In addition, SPARCL1-IR neurons were detected in the nucleus of the trapezoid body and pontine nucleus within the pons and the arcuate nucleus in the medulla oblongata. In the cervical spinal cord, the ventral horn contained some SPARCL1-IR neurons with large cell bodies. These findings suggest that SPARCL1-containing neurons function to relay and regulate motor and sensory signals in the human brainstem. In the dorsal root (DRG) and trigeminal ganglia (TG), primary sensory neurons contained SPARCL1-immunoreactivity. The proportion of SPARCL1-IR neurons in the TG (mean?±?SD, 39.9?±?2.4%) was higher than in the DRG (30.6?±?2.1%). SPARCL1-IR neurons were mostly medium-sized to large (mean?±?SD, 1494.5?±?708.3?μm²; range, 320.4–4353.4?μm²) in the DRG, whereas such neurons were of various cell body sizes in the TG (mean?±?SD, 1291.2?±?532.8?μm²; range, 209.3–4326.4?μm²). There appears to be a SPARCL1-containing sensory pathway in the ganglion and brainstem of the spinal and trigeminal nervous systems.     

Dividing neuron precursors express neuron-specific tubulin

Neuronal differentiation involves specific molecular and morphological changes in precursors and results in mature, postmitotic neurons. The expression of neuron-specific β tubulin, as detected by the monoclonal antibody TuJ1, begins during the period of neurogenesis. Indeed, TuJ1 expression precedes that of the 160 kD neurofilament protein in both the central and peripheral nervous systems. In the embryonic rat spinal cord, bipolar cells and some mitotic cells in the ventricular zone were TuJ1 immunoreactive (IR). Sensory ganglia also contained cells with TuJ1-IR mitotic spindles in situ. In embryonic rat sensory and sympathetic ganglion cell cultures pulsed with the thymidine analog bromodeoxyuridine (BrdU), TuJ1 label was detected in the spindle of mitotic cells and in the midbody of cells joined at cytokinesis, indicating that neuron-specific tubulin expression was initiated during or before the final mitosis of neuronal progenitors. Dorsal root ganglion cultures included TuJ1-IR cells with several shapes that may reflect morphological transitions, from flattened stellate neural crest-like cells to differentiated bipolar neurons. Indeed, the presence of flattened TuJ1-IR cells was correlated with neurogenesis. Some sympathetic neuron precursors possessed long TuJ1-IR neurites, as well as TuJ1-IR spindle microtubules and BrdU-labeled chromosomes, indicating that these precursors can possess long processes during metaphase. These results support the hypothesis that neuron-specific tubulin expression represents an early molecular event in neuronal differentiation exhibited by a wide range of neuronal precursors. The cessation of proliferation can occur at different points during neuronal differentiation, as TuJ1-IR was detected in cells undergoing mitosis. Future studies directed toward understanding the molecules that initiate neuron-specific tubulin expression may lead to the factors that control the initial phases of neuronal differentiation. © 1995 John Wiley & Sons, Inc.     

A novel small molecule HSP90 inhibitor,NXD30001, differentially induces heat shock proteins in nervous tissue in culture and in vivo

Heat shock proteins (HSPs) are attractive therapeutic targets for neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), characterized by aberrant formation of protein aggregates. Although motor neurons have a high threshold for activation of HSP genes, HSP90 inhibitors are effective inducers. This study evaluated NXD30001, a novel, small molecule HSP90 inhibitor based on the radicicol backbone, for its ability to induce neuronal HSPs and for efficacy in an experimental model of ALS based on mutations in superoxide-dismutase 1 (SOD1). In motor neurons of dissociated murine spinal cord cultures, NXD30001-induced expression of HSP70/HSPA1 (iHSP70) and its co-chaperone HSP40/DNAJ through activation of HSF1 and exhibited a protective profile against SOD1^G93A similar to geldanamycin, but with less toxicity. Treatment prevented protein aggregation, mitochondrial fragmentation, and motor neuron death, important features of mutant SOD1 toxicity, but did not effectively prevent aberrant intracellular Ca²⁺ accumulation. NXD30001 distributed to brain and spinal cord of wild-type and SOD1^G93A transgenic mice following intraperitoneal injection; however, unlike in culture, in vivo levels of SOD1 were not reduced. NXD30001-induced expression of iHSP70 in skeletal and cardiac muscle and, to a lesser extent, in kidney, but not in liver, spinal cord, or brain, with either single or repeated administration. NXD30001 is a very useful experimental tool in culture, but these data point to the complex nature of HSP gene regulation in vivo and the necessity for early evaluation of the efficacy of novel HSP inducers in target tissues in vivo.     

HSP70 alleviates spinal cord injury by activating the NF-kB pathway

Objectives:Spinal cord injury (SCI) is an acute traumatic lesion of neurons in the spinal cord which has a high prevalence in the world, and has no effective surgical treatment. HSP70 is a molecular chaperone protein, serves a protective role in several different models of nervous system injury. The aim of the present study was to investigate the anti-inflammatory role of HSP70 in spinal cord injury and explore its mechanism.Methods:In vivo and in vitro models were constructed to mimic SCI. The Basso Mouse Scale (BMS) was applied to assess SCI degrees of the mouse model. Immunofluorescence (IF) was used for visualizing HSP70 and Iba1 in the spinal cord. Western blot assay was employed to quantify HSP70 and p65, and ELISA was for IL-1β and TNF-α.Results:The results showed that HSP70 expression decreased after SCI. HSP70 and Iba1 showed a decrease of co-localization in SCI mice. Further studies revealed that p65 was upregulated during the process of SCI. Overexpression of HSP70 inhibited the expression of p65 both in vitro and in vivo, and promoted the recovery of SCI mice.Conclusions:HSP70 was involved in the pathological process of spinal cord injury, HSP70 alleviated the spinal cord injury via inhibiting NF-κB signaling pathway.     

A 37-year-old spinal cord-injured female patient, transplanted of multipotent stem cells from human UC blood, with improved sensory perception and mobility, both functionally and morphologically: a case study

HLA-matched UC blood-derived multipotent stem cells were directly transplanted into the injured spinal cord site of a 37-year-old female patient suffering from spinal cord injury (SPI). In this case, human cord blood (UCB)-derived multipotent stem cells improved sensory perception and movement in the SPI patient's hips and thighs within 41 days of cell transplantation. CT and MRI results also showed regeneration of the spinal cord at the injured site and some of the cauda equina below it. Therefore, it is suggested that UCB multipotent stem cell transplantation could be a good treatment method for SPI patients.     

Cauda equina syndrome and nitric oxide synthase immunoreactivity in the spinal cord of the dog

The development of the cauda equina syndrome in the dog and the involvement of spinal nitric oxide synthase immunoreactivity (NOS-IR) and catalytic nitric oxide synthase (cNOS) activity were studied in a pain model caused by multiple cauda equina constrictions. Increased NOS-IR was found two days post-constriction in neurons of the deep dorsal horn and in large, mostly bipolar neurons located in the internal basal nucleus of Cajal seen along the medial border of the dorsal horn. Concomitantly, NOS-IR was detected in small neurons close to the medioventral border of the ventral horn. High NOS-IR appeared in a dense sacral vascular body close to the Lissauer tract in S1-S3 segments. Somatic and fiber-like NOS-IR appeared at five days post-constriction in the Lissauer tract and in the lateral and medial collateral pathways arising from the Lissauer tract. Both pathways were accompanied by a dense punctate NOS immunopositive staining. Simultaneously, the internal basal nucleus of Cajal and neuropil of this nucleus exhibited high NOS-IR. A significant decrease in the number of small NOS immunoreactive somata was noted in laminae I-II of L6-S2 segments at five days post-constriction while, at the same time, the number of NOS immunoreactive neurons located in laminae VIII and IX was significantly increased. Moreover, high immunopositivity in the sacral vascular body persisted along with a highly expressed NOS-IR staining of vessels supplying the dorsal sacral gray commissure and dorsal horn in S1-S3 segments. cNOS activity, based on a radioassay of compartmentalized gray and white matter regions of lower lumbar segments and non-compartmentalized gray and white matter of S1-S3 segments, proved to be highly variable for both post-constriction periods.     

Glucocorticoid Regulation of Motoneuronal Parameters in Rats with Spinal Cord Injury

1.Glucocorticoids exert beneficial effects after acute CNS injury in humans and experimental animals. To elucidate potential mechanisms of glucocorticoid action in the lesioned spinal cord, we have studied if treatment with dexamethasone (DEX) modulated the neurotrophin binding receptor p75 (p75^NTR) and choline acetyltransferase (ChAT), a marker of neuronal functional viability.2.Rats with a sham operation or with spinal cord transection at the thoracic level received vehicle or DEX several times postlesion and were sacrificed 48 hr after surgery. The lumbar region caudal to the lesion was processed for p75^NTR and ChAT immunoreactivity (IR) using quantitative densitometric analysis.3.We observed that p75^NTR-IR was absent from ventral horn motoneurons of sham-operated rats, in contrast to strong staining of neuronal perikaryon in TRX rats. Administration of DEX to TRX rats had no effect on the number of neuronal cell bodies expressing p75^NTR-IR but significantly increased the number and length of immunostained neuronal processes.4.Furthermore, spinal cord transection reduced ChAT immunostaining of motoneurons by 50%, whereas DEX treatment reverted this pattern to cells with a strong immunoreaction intensity in perikaryon and cell processes.5.It is hypothesized that increased expression of p75^NTR in cell processes and of ChAT in motoneurons may be part of a mechanism by which glucocorticoids afford neuroprotection, in addition to their known antiinflammatory effects.     

Mutant Cu/Zn-superoxide dismutase proteins have altered solubility and interact with heat shock/stress proteins in models of amyotrophic lateral sclerosis

Mutations in the Cu/Zn-superoxide dismutase (SOD-1) gene are responsible for a familial form of amyotrophic lateral sclerosis. In humans and experimental models, death of motor neurons is preceded by formation of cytoplasmic aggregates containing mutant SOD-1 protein. In our previous studies, heat shock protein 70 (HSP70) prolonged viability of cultured motor neurons expressing mutant human SOD-1 and reduced formation of aggregates. In this paper, we report that mutant SOD-1 proteins have altered solubility in cells relative to wild-type SOD-1 and can form a direct association with HSP70 and other stress proteins. Whereas wild-type human and endogenous mouse SOD-1 were detergent-soluble, a portion of mutant SOD-1 was detergent-insoluble in protein extracts of NIH3T3 transfected with SOD-1 gene constructs, spinal cord cultures established from G93A SOD-1 transgenic mouse embryos, and lumbar spinal cord from adult G93A transgenic mice. A direct association of HSP70, HSP40, and alphaB-crystallin with mutant SOD-1 (G93A or G41S), but not wild-type or endogenous mouse SOD-1, was demonstrated by coimmunoprecipitation. Mutant SOD-1.HSP70 complexes were predominantly in the detergent-insoluble fraction. However, only a small percentage of total cellular mutant SOD-1 was detergent-insoluble, suggesting that mutation-induced alteration of protein conformation may not in itself be sufficient for direct interaction with heat shock proteins.     

Inhibition of gecko GSK-3β promotes elongation of neurites and oligodendrocyte processes but decreases the proliferation of blastemal cells

GSK-3β signaling is involved in regulation of both neuronal and glial cell functions, and interference of the signaling affects central nervous system (CNS) development and regeneration. Thus, GSK-3β was proposed to be an important therapeutic target for promoting functional recovery of adult CNS injuries. To further clarify the regulatory function of the kinase on the CNS regeneration, we characterized gecko GSK-3β and determined the effects of GSK-3β inactivation on the neuronal and glial cell lines, as well as on the gecko tail (including spinal cord) regeneration. Gecko GSK-3β shares 91.7-96.7% identity with those of other vertebrates, and presented higher expression abundance in brain and spinal cord. The kinase strongly colocalized with the oligodendrocytes while less colocalized with neurons in the spinal cord. Phosphorylated GSK-3β (pGSK-3β) levels decreased gradually during the normally regenerating spinal cord ranging from L13 to the 6th caudal vertebra. Lithium injection increased the pGSK-3β levels of the corresponding spinal cord segments, and in vitro experiments on neurons and oligodendrocyte cell line revealed that the elevation of pGSK-3β promoted elongation of neurites and oligodendrocyte processes. In the normally regenerate tails, pGSK-3β kept stable in 2 weeks, whereas decreased at 4 weeks. Injection of lithium led to the elevation of pGSK-3β levels time-dependently, however destructed the regeneration of the tail including spinal cord. Bromodeoxyuridine (BrdU) staining demonstrated that inactivation of GSK-3β decreased the proliferation of blastemal cells. Our results suggested that species-specific regulation of GSK-3β was indispensable for the complete regeneration of CNS.     

The majority of dorsal spinal cord gastrin releasing peptide is synthesized locally whereas neuromedin B is highly expressed in pain- and itch-sensing somatosensory neurons

ABSTRACT: BACKGROUND: Itch is one of the major somatosensory modalities. Some recent findings have proposed that gastrin releasing peptide (Grp) is expressed in a subset of dorsal root ganglion (DRG) neurons and functions as a selective neurotransmitter for transferring itch information to spinal cord interneurons. However, expression data from public databases and earlier literatures indicate that Grp mRNA is only detected in dorsal spinal cord (dSC) whereas its family member neuromedin B (Nmb) is highly expressed in DRG neurons. These contradictory results argue that a thorough characterization of the expression of Grp and Nmb is warranted. FINDINGS: Grp mRNA is highly expressed in dSC but is barely detectable in DRGs of juvenile and adult mice. Anti-bombesin serum specifically recognizes Grp but not Nmb. Grp is present in a small number of small-diameter DRG neurons and in abundance in layers I and II of the spinal cord. The reduction of dSC Grp after dorsal root rhizotomy is significantly different from those of DRG derived markers but similar to that of a spinal cord neuronal marker. Double fluorescent in situ of Nmb and other molecular markers indicate that Nmb is highly and selectively expressed in nociceptive and itch-sensitive DRG neurons. CONCLUSION: The majority of dSC Grp is synthesized locally in dorsal spinal cord neurons. On the other hand, Nmb is highly expressed in pain- and itch-sensing DRG neurons. Our findings provide direct anatomic evidence that Grp could function locally in the dorsal spinal cord in addition to its roles in DRG neurons and that Nmb has potential roles in nociceptive and itch-sensitive neurons. These results will improve our understanding about roles of Grp and Nmb in mediating itch sensation.     

Activity of propriospinal neurons in segments C3 and C4 during fictitious locomotion in cats

Activity of propriospinal neurons in segments C3 and C4 was recorded in immobilized decerebrate cats, whose spinal cord was divided at the lower thoracic level, during locomotor activity of neuronal mechanisms controlling the forelimbs (fictitious locomotion of the forelimbs). Neurons were identified according to antidromic responses to stimulation of the lateral column of the spinal cord at level C6. Antidromic responses also appeared in 70% of these neurons to stimulation of the medullary lateral reticular nucleus. During fictitious locomotion, i.e., in the absence of afferent signals from the limb receptors, rhythmic modulation of the discharge of most neurons was observed, correlating with activity of motoneurons. If the rostral region of the cervical enlargement of the spinal cord was cooled, causing generation of the locomotor rhythm to cease, rhythmic activity of propriospinal neurons in segments C3 and C4 also ceased. The main source of modulation of activity of propriospinal neurons in segments C3 and C4 is thus the central spinal mechanisms controlling activity of the forelimbs.Institute for Problems in Information Transmission, Academy of Sciences of the USSR, Moscow. M. V. Lomonosov Moscow University. Translated from Neirofiziologiya, Vol. 17, No. 3, pp. 320–326, May–June, 1985.     

Short-term changes of NADPH diaphorase-exhibiting neuronal pools in the spinal cord of rabbit after repeated sublethal ischemia

The aim of this study was the histochemical characterization of NADPH diaphorase-positive neuronal pools in the rabbit lumbosacral segments using a model of single, repeated and multiple sublethal spinal cord ischemia. Following a single 8-min sublethal spinal cord ischemia and 1-hour reperfusion, the staining of NADPH diaphorase-exhibiting neurons in the dorsal horn, pericentral region, dorsal gray commissure and sacral parasympathetic nucleus was comparable with the control sections. In contrast to the foregoing sublethal ischemia, a regionally different somatic NADPH diaphorase (NADPHd) staining was found after multiple sublethal spinal cord ischemia. Whereas an almost complete loss of the staining of large NADPHd-exhibiting somata in the pericentral region was detected, the staining of the NADPHd-exhibiting neuronal pools in the deep dorsal horn and sacral parasympathetic nucleus was fully preserved. Concomitantly, a prominent reduction of small NADPH diaphorase-positive neurons was noted in the superficial dorsal horn layers of lower lumbar and sacral segments.