Sample records for a-beta drg neurons

  1. Delayed onset of changes in soma action potential genesis in nociceptive A-beta DRG neurons in vivo in a rat model of osteoarthritis

    Directory of Open Access Journals (Sweden)

    Henry James L


    Full Text Available Abstract Background Clinical data on osteoarthritis (OA suggest widespread changes in sensory function that vary during the progression of OA. In previous studies on a surgically-induced animal model of OA we have observed that changes in structure and gene expression follow a variable trajectory over the initial days and weeks. To investigate mechanisms underlying changes in sensory function in this model, the present electrophysiological study compared properties of primary sensory nociceptive neurons at one and two months after model induction with properties in naïve control animals. Pilot data indicated no difference in C- or Aδ-fiber associated neurons and therefore the focus is on Aβ-fiber nociceptive neurons. Results At one month after unilateral derangement of the knee by cutting the anterior cruciate ligament and removing the medial meniscus, the only changes observed in Aβ-fiber dorsal root ganglion (DRG neurons were in nociceptor-like unresponsive neurons bearing a hump on the repolarization phase; these changes consisted of longer half width, reflecting slowed dynamics of AP genesis, a depolarized Vm and an increased AP amplitude. At two months, changes observed were in Aβ-fiber high threshold mechanoreceptors, which exhibited shorter AP duration at base and half width, shorter rise time and fall time, and faster maximum rising rate/maximum falling rate, reflecting accelerated dynamics of AP genesis. Conclusion These data indicate that Aβ nociceptive neurons undergo significant changes that vary in time and occur later than changes in structure and in nociceptive scores in this surgically induced OA model. Thus, if changes in Aβ-fiber nociceptive neurons in this model reflect a role in OA pain, they may relate to mechanisms underlying pain associated with advanced OA.

  2. Comparative functional expression of nAChR subtypes in rodent DRG neurons

    Directory of Open Access Journals (Sweden)

    Nathan J. Smith


    Full Text Available We investigated the functional expression of nicotinic acetylcholine receptors (nAChRs in heterogeneous populations of dissociated rat and mouse lumbar dorsal root ganglion (DRG neurons by calcium imaging. By this experimental approach, it is possible to investigate the functional expression of multiple receptor and ion-channel subtypes across more than 100 neuronal and glial cells simultaneously. Based on nAChR expression, DRG neurons could be divided into four subclasses: 1 neurons that express predominantly alpha3beta4 and alpha6beta4 nAChRs; 2 neurons that express predominantly alpha7 nAChRs; 3 neurons that express a combination of alpha3beta4/alpha6beta4 and alpha7 nAChRs; and 4 neurons that do not express nAChRs. In this comparative study, the same four neuronal subclasses were observed in mouse and rat DRG. However, the expression frequency differed between species: substantially more rat DRG neurons were in the first three subclasses than mouse DRG neurons, at all developmental time points tested in our study. Approximately 70-80% of rat DRG neurons expressed functional nAChRs, in contrast to only ~15-30% of mouse DRG neurons. Our study also demonstrated functional coupling between nAChRs, voltage-gated calcium channels and mitochondrial Ca2+ transport in discrete subsets of DRG neurons. In contrast to the expression of nAChRs in DRG neurons, we demonstrated that a subset of non-neuronal DRG cells expressed muscarinic acetylcholine receptors (mAChRs and not nAChRs. The general approach to comparative cellular neurobiology outlined in this paper has the potential to better integrate molecular and systems neuroscience by uncovering the spectrum of neuronal subclasses present in a given cell population and the functionally integrated signaling components expressed in each subclass.

  3. Nav1.7-related small fiber neuropathy: impaired slow-inactivation and DRG neuron hyperexcitability.

    NARCIS (Netherlands)

    Han, C.; Hoeijmakers, J.G.; Ahn, H.S.; Zhao, P.; Shah, P.; Lauria, G.; Gerrits, M.M.; Morsche, R.H.M. te; Dib-Hajj, S.D.; Drenth, J.P.H.; Faber, C.G.; Merkies, I.S.; Waxman, S.G.


    OBJECTIVES: Although small fiber neuropathy (SFN) often occurs without apparent cause, the molecular etiology of idiopathic SFN (I-SFN) has remained enigmatic. Sodium channel Na(v)1.7 is preferentially expressed within dorsal root ganglion (DRG) and sympathetic ganglion neurons and their small-diame

  4. Sensory discrimination between innocuous and noxious cold by TRPM8-expressing DRG neurons of rats

    Directory of Open Access Journals (Sweden)

    Sarria Ignacio


    Full Text Available Abstract The TRPM8 channel is a principal cold transducer that is expressed on some primary afferents of the somatic and cranial sensory systems. However, it is uncertain whether TRPM8-expressing afferent neurons have the ability to convey innocuous and noxious cold stimuli with sensory discrimination between the two sub-modalities. Using rat dorsal root ganglion (DRG neurons and the patch-clamp recording technique, we characterized membrane and action potential properties of TRPM8-expressing DRG neurons at 24°C and 10°C. TRPM8-expressing neurons could be classified into TTX-sensitive (TTXs/TRPM8 and TTX-resistant (TTXr/TRPM8 subtypes based on the sensitivity to tetrodotoxin (TTX block of their action potentials. These two subtypes of cold-sensing cells displayed different membrane and action potential properties. Voltage-activated inward Na+ currents were highly susceptible to cooling temperature and abolished by ~95% at 10°C in TTXs/TRPM8 DRG neurons, but remained substantially large at 10°C in TTXr/TRPM8 cells. In both TTXs/TRPM8 and TTXr/TRPM8 cells, voltage-activated outward K+ currents were substantially inhibited at 10°C, and the cooling-sensitive outward currents resembled A-type K+ currents. TTXs/TRPM8 neurons and TTXr/TRPM8 neurons were shown to fire action potentials at innocuous and noxious cold temperatures respectively, demonstrating sensory discrimination between innocuous and noxious cold by the two subpopulations of cold-sensing DRG neurons. The effects of cooling temperatures on voltage-gated Na+ channels and A-type K+ currents are likely to be contributing factors to sensory discrimination of cold by TTXs/TRPM8 and TTXr/TRPM8 afferent neurons.

  5. Reactive oxygen species mediate TNFR1 increase after TRPV1 activation in mouse DRG neurons

    Directory of Open Access Journals (Sweden)

    Westlund Karin N


    Full Text Available Abstract Background Transient receptor potential vanilloid subtype 1 (TRPV1 is activated by low pH/protons and is well known to be involved in hyperalgesia during inflammation. Tumor necrosis factor α (TNF-α, a proinflammatory cytokine, is involved in nociceptive responses causing hyperalgesia through TNF receptor type 1 (TNFR1 activation. Reactive oxygen species (ROS production is also prominently increased in inflamed tissue. The present study investigated TNFR1 receptors in primary cultured mouse dorsal root ganglion (DRG neurons after TRPV1 activation and the involvement of ROS. C57BL/6 mice, both TRPV1 knockout and wild type, were used for immunofluorescent and live cell imaging. The L4 and L5 DRGs were dissected bilaterally and cultured overnight. TRPV1 was stimulated with capsaicin or its potent analog, resiniferatoxin. ROS production was measured with live cell imaging and TNFR1 was detected with immunofluorescence in DRG primary cultures. The TRPV1 knockout mice, TRPV1 antagonist, capsazepine, and ROS scavenger, N-tert-Butyl-α-phenylnitrone (PBN, were employed to explore the functional relationship among TRPV1, ROS and TNFR1 in these studies. Results The results demonstrate that TRPV1 activation increases TNFR1 receptors and ROS generation in primary cultures of mouse DRG neurons. Activated increases in TNFR1 receptors and ROS production are absent in TRPV1 deficient mice. The PBN blocks increases in TNFR1 and ROS production induced by capsaicin/resiniferatoxin. Conclusion TRPV1 activation increases TNFR1 in cultured mouse DRG neurons through a ROS signaling pathway, a novel sensitization mechanism in DRG neurons.

  6. Sensitization of capsaicin and icilin responses in oxaliplatin treated adult rat DRG neurons

    Directory of Open Access Journals (Sweden)

    Anand Praveen


    Full Text Available Abstract Background Oxaliplatin chemotherapy induced neuropathy is a dose related cumulative toxicity that manifests as tingling, numbness, and chronic pain, compromising the quality of life and leading to discontinued chemotherapy. Patients report marked hypersensitivity to cold stimuli at early stages of treatment, when sensory testing reveals cold and heat hyperalgesia. This study examined the morphological and functional effects of oxaliplatin treatment in cultured adult rat DRG neurons. Results 48 hour exposure to oxaliplatin resulted in dose related reduction in neurite length, density, and number of neurons compared to vehicle treated controls, using Gap43 immunostaining. Neurons treated acutely with 20 μg/ml oxaliplatin showed significantly higher signal intensity for cyclic AMP immunofluorescence (160.5 ± 13 a.u., n = 3, P Conclusions Oxaliplatin treatment induces TRP sensitization mediated by increased intracellular cAMP, which may cause neuronal damage. These effects may be mitigated by co-treatment with adenylyl cyclase inhibitors, like CB2 agonists, to alleviate the neurotoxic effects of oxaliplatin.

  7. Neuronal IL-17 receptor upregulates TRPV4 but not TRPV1 receptors in DRG neurons and mediates mechanical but not thermal hyperalgesia. (United States)

    Segond von Banchet, Gisela; Boettger, Michael K; König, Christian; Iwakura, Yoichiro; Bräuer, Rolf; Schaible, Hans-Georg


    In addition to the proinflammatory cytokines tumor necrosis factor-α, interleukin-6 and interleukin-1ß, the cytokine interleukin-17 (IL-17) is considered an important mediator of autoimmune diseases such as rheumatoid arthritis. Because tumor necrosis factor-α and interleukin-1ß have the potential to influence the expression of transduction molecules such as transient receptor potential vanilloid 1 (TRPV1) in dorsal root ganglion (DRG) neurons and thus to contribute to pain we explored in the present study whether IL-17A activates DRG neurons and influences the expression of TRPV1. The IL-17A receptor was visualized in most neurons in dorsal root ganglion (DRG) sections as well as in cultured DRG neurons. Upon long-term exposure to IL-17A, isolated and cultured rat DRG neurons showed a significant upregulation of extracellular-regulated kinase (ERK) and nuclear factor κB (NFκB). Long-term exposure of neurons to IL-17A did not upregulate the expression of TRPV1. However, we found a pronounced upregulation of transient receptor potential vanilloid 4 (TRPV4) which is considered a candidate transduction molecule for mechanical hyperalgesia. Upon the injection of zymosan into the paw, IL-17A-deficient mice showed less mechanical hyperalgesia than wild type mice but thermal hyperalgesia was not attenuated in IL-17A-deficient mice. These data show, therefore, a particular role of IL-17 in mechanical hyperalgesia, and they suggest that this effect is linked to an activation and upregulation of TRPV4.

  8. Blockade of persistent sodium currents contributes to the riluzole-induced inhibition of spontaneous activity and oscillations in injured DRG neurons.

    Directory of Open Access Journals (Sweden)

    Rou-Gang Xie

    Full Text Available In addition to a fast activating and immediately inactivating inward sodium current, many types of excitable cells possess a noninactivating or slowly inactivating component: the persistent sodium current (I(NaP. The I(NaP is found in normal primary sensory neurons where it is mediated by tetrodotoxin-sensitive sodium channels. The dorsal root ganglion (DRG is the gateway for ectopic impulses that originate in pathological pain signals from the periphery. However, the role of I(NaP in DRG neurons remains unclear, particularly in neuropathic pain states. Using in vivo recordings from single medium- and large-diameter fibers isolated from the compressed DRG in Sprague-Dawley rats, we show that local application of riluzole, which blocks the I(NaP, also inhibits the spontaneous activity of A-type DRG neurons in a dose-dependent manner. Significantly, riluzole also abolished subthreshold membrane potential oscillations (SMPOs, although DRG neurons still responded to intracellular current injection with a single full-sized spike. In addition, the I(NaP was enhanced in medium- and large-sized neurons of the compressed DRG, while bath-applied riluzole significantly inhibited the I(NaP without affecting the transient sodium current (I(NaT. Taken together, these results demonstrate for the first time that the I(NaP blocker riluzole selectively inhibits I(NaP and thereby blocks SMPOs and the ectopic spontaneous activity of injured A-type DRG neurons. This suggests that the I(NaP of DRG neurons is a potential target for treating neuropathic pain at the peripheral level.

  9. In vitro activation of murine DRG neurons by CGRP-mediated mucosal mast cell degranulation

    NARCIS (Netherlands)

    De Jonge, F; De Laet, A; Van Nassauw, L; Miller, HRP; van Bogaert, PP; Timmermans, JP; Kroese, ABA


    Upregulation of CGRP-immunoreactive (IR) primary afferent nerve fibers accompanied by mastocytosis is characteristic for the Schistosoma mansoni-infected murine ileum. These mucosal mast cells (MMC) and CGRP-IR fibers, which originate from dorsal root (DRG) and nodose ganglia, are found in close app

  10. Inhibition of Hyperpolarization-Activated Cation Current in Medium-Sized DRG Neurons Contributed to the Antiallodynic Effect of Methylcobalamin in the Rat of a Chronic Compression of the DRG

    Directory of Open Access Journals (Sweden)

    Ming Zhang


    Full Text Available Recently several lines of evidence demonstrated that methylcobalamin (MeCbl might have potential analgesic effect in experimental and clinical studies. However, it was reported that MeCbl had no effect on treating lumbar spinal stenosis induced pain. Thus, the effects of short-term and long-term administration of MeCbl were examined in the chronic compression of dorsal root ganglion (CCD model. We found that mechanical allodynia was significantly inhibited by a continuous application of high dose and a single treatment of a super high dose of MeCbl. Little is known about mechanisms underlying the analgesia of MeCbl. We examined the effect of MeCbl on the spontaneous activity (SA, the excitability, and hyperpolarization-activated nonselective cation ion current in compressed medium-sized dorsal root ganglion (DRG neurons using extracellular single fiber recording in vivo and whole-cell patch clamp in vitro. We found that MeCbl significantly inhibited the SA of A-type sensory neurons in a dose-dependent manner and inhibited the excitability of medium-sized DRG neurons. In addition, MeCbl also decreased Ih current density in injured medium-sized DRG neurons. Our results proved that MeCbl might exert an analgesic effect through the inhibition Ih current and then might inhibit the hyperexcitability of primary sensory neurons under neuropathic pain state.

  11. Inhibition of Hyperpolarization-Activated Cation Current in Medium-Sized DRG Neurons Contributed to the Antiallodynic Effect of Methylcobalamin in the Rat of a Chronic Compression of the DRG. (United States)

    Zhang, Ming; Han, Wenjuan; Zheng, Jianyong; Meng, Fancheng; Jiao, Xiying; Hu, Sanjue; Xu, Hui


    Recently several lines of evidence demonstrated that methylcobalamin (MeCbl) might have potential analgesic effect in experimental and clinical studies. However, it was reported that MeCbl had no effect on treating lumbar spinal stenosis induced pain. Thus, the effects of short-term and long-term administration of MeCbl were examined in the chronic compression of dorsal root ganglion (CCD) model. We found that mechanical allodynia was significantly inhibited by a continuous application of high dose and a single treatment of a super high dose of MeCbl. Little is known about mechanisms underlying the analgesia of MeCbl. We examined the effect of MeCbl on the spontaneous activity (SA), the excitability, and hyperpolarization-activated nonselective cation ion current in compressed medium-sized dorsal root ganglion (DRG) neurons using extracellular single fiber recording in vivo and whole-cell patch clamp in vitro. We found that MeCbl significantly inhibited the SA of A-type sensory neurons in a dose-dependent manner and inhibited the excitability of medium-sized DRG neurons. In addition, MeCbl also decreased I h current density in injured medium-sized DRG neurons. Our results proved that MeCbl might exert an analgesic effect through the inhibition I h current and then might inhibit the hyperexcitability of primary sensory neurons under neuropathic pain state.

  12. Docosahexaenoic acid inhibits mechanical allodynia and thermal hyperalgesia in diabetic rats by decreasing the excitability of DRG neurons. (United States)

    Heng, Li-Jun; Qi, Rui; Yang, Rui-Hua; Xu, Guo-Zheng


    Diabetes mellitus is a common metabolic disease in human beings with characteristic symptoms of hyperglycemia, chronic inflammation and insulin resistance. One of the most common complications of early-onset diabetes mellitus is peripheral diabetic neuropathy, which is manifested either by loss of nociception or by allodynia and hyperalgesia. Dietary fatty acids, especially polyunsaturated fatty acids, have been shown the potential of anti-inflammation and modulating neuron excitability. The present study investigated the effects of docosahexaenoic acid (DHA) on the excitability of dorsal root ganglion (DRG) neurons in streptozotocin (STZ)-induced diabetes rats. The effects of DHA on the allodynia and hyperalgesia of diabetic rats were also evaluated. Dietary DHA supplementation effectively attenuated both allodynia and hyperalgesia induced by STZ injection. DHA supplementation decreased the excitability of DRG neurons by decreasing the sodium currents and increasing potassium currents, which may contribute to the effect of alleviating allodynia and hyperalgesia in diabetic rats. The results suggested that DHA might be useful as an adjuvant therapy for the prevention and treatment of painful diabetic neuropathy.

  13. Inhibitory effects of CB1 and CB2 receptor agonists on responses of DRG neurons and dorsal horn neurons in neuropathic rats. (United States)

    Sagar, Devi Rani; Kelly, Sara; Millns, Paul J; O'Shaughnessey, Celestine T; Kendall, David A; Chapman, Victoria


    Cannabinoid 2 (CB2) receptor mediated antinociception and increased levels of spinal CB2 receptor mRNA are reported in neuropathic Sprague-Dawley rats. The aim of this study was to provide functional evidence for a role of peripheral, vs. spinal, CB2 and cannabinoid 1 (CB1) receptors in neuropathic rats. Effects of the CB2 receptor agonist, JWH-133, and the CB1 receptor agonist, arachidonyl-2-chloroethylamide (ACEA), on primary afferent fibres were determined by calcium imaging studies of adult dorsal root ganglion (DRG) neurons taken from neuropathic and sham-operated rats. Capsaicin (100 nm) increased [Ca2+]i in DRG neurons from sham and neuropathic rats. JWH-133 (3 microm) or ACEA (1 microm) significantly (PCB2 receptor antagonist, SR144528, (1 microm) significantly inhibited the effects of JWH-133. Effects of ACEA were significantly inhibited by the CB1 receptor antagonist SR141716A (1 microm). In vivo experiments evaluated the effects of spinal administration of JWH-133 (8-486 ng/50 microL) and ACEA (0.005-500 ng/50 microL) on mechanically evoked responses of neuropathic and sham-operated rats. Spinal JWH-133 attenuated mechanically evoked responses of spinal neurons in neuropathic, but not sham-operated rats. These inhibitory effects were blocked by SR144528 (0.001 microg/50 microL). Spinal ACEA inhibited mechanically evoked responses of neuropathic and sham-operated rats, these effects were blocked by SR141716A (0.01 microg/50 microL). Our data provide evidence for a functional role of CB2, as well as CB1 receptors on DRG neurons in sham and neuropathic rats. At the level of the spinal cord, CB2 receptors have inhibitory effects in neuropathic, but not sham-operated rats suggesting that spinal CB2 may be an important analgesic target.

  14. Paroxysmal extreme pain disorder M1627K mutation in human Nav1.7 renders DRG neurons hyperexcitable

    Directory of Open Access Journals (Sweden)

    Tyrrell Lynda


    Full Text Available Abstract Background Paroxysmal extreme pain disorder (PEPD is an autosomal dominant painful neuropathy with many, but not all, cases linked to gain-of-function mutations in SCN9A which encodes voltage-gated sodium channel Nav1.7. Severe pain episodes and skin flushing start in infancy and are induced by perianal probing or bowl movement, and pain progresses to ocular and mandibular areas with age. Carbamazepine has been effective in relieving symptoms, while other drugs including other anti-epileptics are less effective. Results Sequencing of SCN9A coding exons from an English patient, diagnosed with PEPD, has identified a methionine 1627 to lysine (M1627K substitution in the linker joining segments S4 and S5 in domain IV. We confirm that M1627K depolarizes the voltage-dependence of fast-inactivation without substantially altering activation or slow-inactivation, and inactivates from the open state with slower kinetics. We show here that M1627K does not alter development of closed-state inactivation, and that M1627K channels recover from fast-inactivation faster than wild type channels, and produce larger currents in response to a slow ramp stimulus. Using current-clamp recordings, we also show that the M1627K mutant channel reduces the threshold for single action potentials in DRG neurons and increases the number of action potentials in response to graded stimuli. Conclusion M1627K mutation was previously identified in a sporadic case of PEPD from France, and we now report it in an English family. We confirm the initial characterization of mutant M1627K effect on fast-inactivation of Nav1.7 and extend the analysis to other gating properties of the channel. We also show that M1627K mutant channels render DRG neurons hyperexcitable. Our new data provide a link between altered channel biophysics and pain in PEPD patients.

  15. Effects of ranolazine on wild-type and mutant hNav1.7 channels and on DRG neuron excitability

    Directory of Open Access Journals (Sweden)

    Estacion Mark


    Full Text Available Abstract Background A direct role of sodium channels in pain has recently been confirmed by establishing a monogenic link between SCN9A, the gene which encodes sodium channel Nav1.7, and pain disorders in humans, with gain-of-function mutations causing severe pain syndromes, and loss-of-function mutations causing congenital indifference to pain. Expression of sodium channel Nav1.8 in DRG neurons has also been shown to be essential for the manifestation of mutant Nav1.7-induced neuronal hyperexcitability. These findings have confirmed key roles of Nav1.7 and Nav1.8 in pain and identify these channels as novel targets for pain therapeutic development. Ranolazine preferentially blocks cardiac late sodium currents at concentrations that do not significantly reduce peak sodium current. Ranolazine also blocks wild-type Nav1.7 and Nav1.8 channels in a use-dependent manner. However, ranolazine's effects on gain-of-function mutations of Nav1.7 and on DRG neuron excitability have not been investigated. We used voltage- and current-clamp recordings to evaluate the hypothesis that ranolazine may be effective in regulating Nav1.7-induced DRG neuron hyperexcitability. Results We show that ranolazine produces comparable block of peak and ramp currents of wild-type Nav1.7 and mutant Nav1.7 channels linked to Inherited Erythromelalgia and Paroxysmal Extreme Pain Disorder. We also show that ranolazine, at a clinically-relevant concentration, blocks high-frequency firing of DRG neurons expressing wild-type but not mutant channels. Conclusions Our data suggest that ranalozine can attenuate hyperexcitability of DRG neurons over-expressing wild-type Nav1.7 channels, as occurs in acquired neuropathic and inflammatory pain, and thus merits further study as an alternative to existing non-selective sodium channel blockers.

  16. Depolarized Inactivation Overcomes Impaired Activation to Produce DRG Neuron Hyperexcitability in a Nav1.7 Mutation in a Patient with Distal Limb Pain

    NARCIS (Netherlands)

    Huang, J.; Yang, Y; Dib-Hajj, S.D.; Es, M. van; Zhao, P.; Salomon, J.; Drenth, J.P.; Waxman, S.G.


    Sodium channel Nav1.7, encoded by SCN9A, is expressed in DRG neurons and regulates their excitability. Genetic and functional studies have established a critical contribution of Nav1.7 to human pain disorders. We have now characterized a novel Nav1.7 mutation (R1279P) from a female human subject wit

  17. Expression of Nav1.7 in DRG neurons extends from peripheral terminals in the skin to central preterminal branches and terminals in the dorsal horn

    Directory of Open Access Journals (Sweden)

    Black Joel A


    Full Text Available Abstract Background Sodium channel Nav1.7 has emerged as a target of considerable interest in pain research, since loss-of-function mutations in SCN9A, the gene that encodes Nav1.7, are associated with a syndrome of congenital insensitivity to pain, gain-of-function mutations are linked to the debiliting chronic pain conditions erythromelalgia and paroxysmal extreme pain disorder, and upregulated expression of Nav1.7 accompanies pain in diabetes and inflammation. Since Nav1.7 has been implicated as playing a critical role in pain pathways, we examined by immunocytochemical methods the expression and distribution of Nav1.7 in rat dorsal root ganglia neurons, from peripheral terminals in the skin to central terminals in the spinal cord dorsal horn. Results Nav1.7 is robustly expressed within the somata of peptidergic and non-peptidergic DRG neurons, and along the peripherally- and centrally-directed C-fibers of these cells. Nav1.7 is also expressed at nodes of Ranvier in a subpopulation of Aδ-fibers within sciatic nerve and dorsal root. The peripheral terminals of DRG neurons within skin, intraepidermal nerve fibers (IENF, exhibit robust Nav1.7 immunolabeling. The central projections of DRG neurons in the superficial lamina of spinal cord dorsal horn also display Nav1.7 immunoreactivity which extends to presynaptic terminals. Conclusions The expression of Nav1.7 in DRG neurons extends from peripheral terminals in the skin to preterminal central branches and terminals in the dorsal horn. These data support a major contribution for Nav1.7 in pain pathways, including action potential electrogenesis, conduction along axonal trunks and depolarization/invasion of presynaptic axons. The findings presented here may be important for pharmaceutical development, where target engagement in the right compartment is essential.

  18. Inactivation properties of sodium channel Nav1.8 maintain action potential amplitude in small DRG neurons in the context of depolarization

    Directory of Open Access Journals (Sweden)

    Waxman Stephen G


    Full Text Available Abstract Background Small neurons of the dorsal root ganglion (DRG express five of the nine known voltage-gated sodium channels. Each channel has unique biophysical characteristics which determine how it contributes to the generation of action potentials (AP. To better understand how AP amplitude is maintained in nociceptive DRG neurons and their centrally projecting axons, which are subjected to depolarization within the dorsal horn, we investigated the dependence of AP amplitude on membrane potential, and how that dependence is altered by the presence or absence of sodium channel Nav1.8. Results In small neurons cultured from wild type (WT adult mouse DRG, AP amplitude decreases as the membrane potential is depolarized from -90 mV to -30 mV. The decrease in amplitude is best fit by two Boltzmann equations, having V1/2 values of -73 and -37 mV. These values are similar to the V1/2 values for steady-state fast inactivation of tetrodotoxin-sensitive (TTX-s sodium channels, and the tetrodotoxin-resistant (TTX-r Nav1.8 sodium channel, respectively. Addition of TTX eliminates the more hyperpolarized V1/2 component and leads to increasing AP amplitude for holding potentials of -90 to -60 mV. This increase is substantially reduced by the addition of potassium channel blockers. In neurons from Nav1.8(-/- mice, the voltage-dependent decrease in AP amplitude is characterized by a single Boltzmann equation with a V1/2 value of -55 mV, suggesting a shift in the steady-state fast inactivation properties of TTX-s sodium channels. Transfection of Nav1.8(-/- DRG neurons with DNA encoding Nav1.8 results in a membrane potential-dependent decrease in AP amplitude that recapitulates WT properties. Conclusion We conclude that the presence of Nav1.8 allows AP amplitude to be maintained in DRG neurons and their centrally projecting axons even when depolarized within the dorsal horn.

  19. Expression of mRNAs for PPT, CGRP, NF-200, and MAP-2 in cocultures of dissociated DRG neurons and skeletal muscle cells in administration of NGF or NT-3

    Directory of Open Access Journals (Sweden)

    Weiwei Zhang


    Full Text Available Both neurotrophins (NTs and target skeletal muscle (SKM cells are essential for the maintenance of the function of neurons and nerve-muscle communication. However, much less is known about the association of target SKM cells with distinct NTs on the expression of mRNAs for preprotachykinin (PPT, calcitonin-gene related peptide (CGRP, neurofilament 200 (NF-200, and microtubule associated protein 2 (MAP-2 in dorsal root ganglion (DRG sensory neurons. In the present study, a neuromuscular coculture model of dissociated dorsal root ganglion (DRG neurons and SKM cells was established. The morphology of DRG neurons and SKM cells in coculture was observed with an inverted phase contrast microscope. The effects of nerve growth factor (NGF or neurotrophin-3 (NT-3 on the expression of mRNAs for PPT, CGRP, NF-200, and MAP-2 was analyzed by real time-PCR assay. The morphology of DRG neuronal cell bodies and SKM cells in neuromuscular coculture at different conditions was similar. The neurons presented evidence of dense neurite outgrowth in the presence of distinct NTs in neuromuscular cocultures. NGF and NT-3 increased mRNA levels of PPT, CGRP, and NF-200, but not MAP-2, in neuromuscular cocultures. These results offer new clues towards a better understanding of the association of target SKM cells with distinct NTs on the expression of mRNAs for PPT, CGRP, NF-200 and MAP-2, and implicate the association of target SKM cells and NTs with DRG sensory neuronal phenotypes.

  20. Distinct subclassification of DRG neurons innervating the distal colon and glans penis/distal urethra based on the electrophysiological current signature. (United States)

    Rau, Kristofer K; Petruska, Jeffrey C; Cooper, Brian Y; Johnson, Richard D


    Spinal sensory neurons innervating visceral and mucocutaneous tissues have unique microanatomic distribution, peripheral modality, and physiological, pharmacological, and biophysical characteristics compared with those neurons that innervate muscle and cutaneous tissues. In previous patch-clamp electrophysiological studies, we have demonstrated that small- and medium-diameter dorsal root ganglion (DRG) neurons can be subclassified on the basis of their patterns of voltage-activated currents (VAC). These VAC-based subclasses were highly consistent in their action potential characteristics, responses to algesic compounds, immunocytochemical expression patterns, and responses to thermal stimuli. For this study, we examined the VAC of neurons retrogradely traced from the distal colon and the glans penis/distal urethra in the adult male rat. The afferent population from the distal colon contained at least two previously characterized cell types observed in somatic tissues (types 5 and 8), as well as four novel cell types (types 15, 16, 17, and 18). In the glans penis/distal urethra, two previously described cell types (types 6 and 8) and three novel cell types (types 7, 14, and 15) were identified. Other characteristics, including action potential profiles, responses to algesic compounds (acetylcholine, capsaicin, ATP, and pH 5.0 solution), and neurochemistry (expression of substance P, CGRP, neurofilament, TRPV1, TRPV2, and isolectin B4 binding) were consistent for each VAC-defined subgroup. With identification of distinct DRG cell types that innervate the distal colon and glans penis/distal urethra, future in vitro studies related to the gastrointestinal and urogenital sensory function in normal as well as abnormal/pathological conditions may be benefitted.

  1. [DRG and gastrointestinal surgery]. (United States)

    Leardi, S; Altilia, F; Pietroletti, R; Risetti, A; Schietroma, M; Simi, M


    The diagnosis-related-groups (DRG) is the cost-based system for hospital reimbursement. However, the proceeds does not coincide with the costs. Aim of the study was to identify the profit, which we could gained with 147, 155, 158, 162, 165, 198 gastrointestinal surgery DRG. 30 consecutive patients, undergone to surgery in Clinica Chirurgica of L'Aquila University, had been studied. We had calculated the daily costs of medical and nursing practice, diagnostic tests, drugs, hospitalization, surgical instruments for every patient's therapy. The DRG-proceeds had been correlated with the DRG-costs. The "major gastrointestinal surgery" had not profit (147 DRG: anterior resection of rectum = -354428 Pounds, Miles = -94020 Pounds; 155 DRG: total gastrectomy = -1920641 Pounds). On the contrary, "minimal surgery" had good profits (158 DRG: hemorroidectomy with local anestesia = 1469605 Pounds;162 DRG: sutureless groin hernioplasty = 1561200 Pounds; 198 DRG: videolaparochole-cystectomy: 1208807 Pounds). The study seems to demonstrate the disparity of the reimbursement system related to DRG. However, the surgeons, as managers, must employ warily the resources for producing DRG.

  2. The role of TNF-alpha/NF-kappa B pathway on the up-regulation of voltage-gated sodium channel Nav1.7 in DRG neurons of rats with diabetic neuropathy. (United States)

    Huang, Yangliang; Zang, Ying; Zhou, Lijun; Gui, Wenshan; Liu, Xianguo; Zhong, Yi


    Diabetic neuropathy (DN) is a common form of peripheral neuropathy, yet the mechanisms responsible for chronic pain in this disease are poorly understood. The up-regulation of the expression and function of voltage-gated sodium channel Nav1.7 has been implicated in DN, however, the exact mechanism is unclear. In the present study, we found that a proportion of streptozotocin (STZ)-treated rats suffered from mechanical allodynia and thermal hyperalgesia for a long-lasting time. Nav1.7 was up-regulated in spinal dorsal root ganglia (DRG) of rats with DN, double immunofluorescence staining showed that the increased Nav1.7 was co-localized with large and small sized neurons but not satellite glial cells. Inhibiting the synthesis of tumor necrosis factor-α (TNF-α) by thalidomide prevented DN, accompanied by strongly blocking the up-regulation of Nav1.7, TNF-α and p-nucleus factor-kappa B (p-NF-κB) in DRG. Intrathecal injection of NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) significantly attenuated the pain behaviors and over-expression of Nav1.7 in DRG neurons. These data suggest that increased TNF-α may be responsible for up-regulation of Nav1.7 in DRG neurons of rats with DN, and NF-κB signal pathway is involved in this process. The findings might provide potential target for preventing diabetic neuropathy.

  3. TRPV1 channels are functionally coupled with BK(mSlo1 channels in rat dorsal root ganglion (DRG neurons.

    Directory of Open Access Journals (Sweden)

    Ying Wu

    Full Text Available The transient receptor potential vanilloid receptor 1 (TRPV1 channel is a nonselective cation channel activated by a variety of exogenous and endogenous physical and chemical stimuli, such as temperature (≥42 °C, capsaicin, a pungent compound in hot chili peppers, and allyl isothiocyanate. Large-conductance calcium- and voltage-activated potassium (BK channels regulate the electric activities and neurotransmitter releases in excitable cells, responding to changes in membrane potentials and elevation of cytosolic calcium ions (Ca(2+. However, it is unknown whether the TRPV1 channels are coupled with the BK channels. Using patch-clamp recording combined with an infrared laser device, we found that BK channels could be activated at 0 mV by a Ca(2+ influx through TRPV1 channels not the intracellular calcium stores in submilliseconds. The local calcium concentration around BK is estimated over 10 μM. The crosstalk could be affected by 10 mM BAPTA, whereas 5 mM EGTA was ineffectual. Fluorescence and co-immunoprecipitation experiments also showed that BK and TRPV1 were able to form a TRPV1-BK complex. Furthermore, we demonstrated that the TRPV1-BK coupling also occurs in dosal root ganglion (DRG cells, which plays a critical physiological role in regulating the "pain" signal transduction pathway in the peripheral nervous system.

  4. TRPV1 channels are functionally coupled with BK(mSlo1) channels in rat dorsal root ganglion (DRG) neurons. (United States)

    Wu, Ying; Liu, Yongfeng; Hou, Panpan; Yan, Zonghe; Kong, Wenjuan; Liu, Beiying; Li, Xia; Yao, Jing; Zhang, Yuexuan; Qin, Feng; Ding, Jiuping


    The transient receptor potential vanilloid receptor 1 (TRPV1) channel is a nonselective cation channel activated by a variety of exogenous and endogenous physical and chemical stimuli, such as temperature (≥42 °C), capsaicin, a pungent compound in hot chili peppers, and allyl isothiocyanate. Large-conductance calcium- and voltage-activated potassium (BK) channels regulate the electric activities and neurotransmitter releases in excitable cells, responding to changes in membrane potentials and elevation of cytosolic calcium ions (Ca(2+)). However, it is unknown whether the TRPV1 channels are coupled with the BK channels. Using patch-clamp recording combined with an infrared laser device, we found that BK channels could be activated at 0 mV by a Ca(2+) influx through TRPV1 channels not the intracellular calcium stores in submilliseconds. The local calcium concentration around BK is estimated over 10 μM. The crosstalk could be affected by 10 mM BAPTA, whereas 5 mM EGTA was ineffectual. Fluorescence and co-immunoprecipitation experiments also showed that BK and TRPV1 were able to form a TRPV1-BK complex. Furthermore, we demonstrated that the TRPV1-BK coupling also occurs in dosal root ganglion (DRG) cells, which plays a critical physiological role in regulating the "pain" signal transduction pathway in the peripheral nervous system.

  5. Digital Raster Graphics (DRG) Lambert (United States)

    Kansas Data Access and Support Center — The Digital Raster Graphic-Lambert (DRG-Lam) is a raster image of a scanned USGS topographic map with the collar information clipped out, georeferenced to the...

  6. The Effects of IGF-1 on TNF-α-Treated DRG Neurons by Modulating ATF3 and GAP-43 Expression via PI3K/Akt/S6K Signaling Pathway. (United States)

    Zhang, Lei; Yue, Yaping; Ouyang, Meishuo; Liu, Huaxiang; Li, Zhenzhong


    Upregulation of the pro-inflammatory cytokine tumor necrosis factor α (TNF-α) is involved in the development and progression of numerous neurological disorders. Recent reports have challenged the concept that TNF-α exhibits only deleterious effects of pro-inflammatory destruction, and have raised the awareness that it may play a beneficial role in neuronal growth and function in particular conditions, which prompts us to further investigate the role of this cytokine. Insulin-like growth factor-1 (IGF-1) is a cytokine possessing powerful neuroprotective effects in promoting neuronal survival, neuronal differentiation, neurite elongation, and neurite regeneration. The association of IGF-1 with TNF-α and the biological effects, produced by interaction of IGF-1 and TNF-α, on neuronal outgrowth status of primary sensory neurons are still to be clarified. In the present study, using an in vitro model of primary cultured rat dorsal root ganglion (DRG) neurons, we demonstrated that TNF-α challenge at different concentrations elicited diverse biological effects. Higher concentration of TNF-α (10 ng/mL) dampened neurite outgrowth, induced activating transcription factor 3 (ATF3) expression, reduced growth-associated protein 43 (GAP-43) expression, and promoted GAP-43 and ATF3 coexpression, which could be reversed by IGF-1 treatment; while lower concentration of TNF-α (1 ng/mL) promoted neurite sprouting, decreased ATF3 expression, increased GAP-43 expression, and inhibited GAP-43 and ATF3 coexpression, which could be potentiated by IGF-1 supplement. Moreover, IGF-1 administration restored the activation of Akt and p70 S6 kinase (S6K) suppressed by higher concentration of TNF-α (10 ng/mL) challenge. In contrast, lower concentration of TNF-α (1 ng/mL) had no significant effect on Akt or S6K activation, and IGF-1 administration activated these two kinases. The effects of IGF-1 were abrogated by phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. These data

  7. Dopamine Potentialization of ATP-Activated Currents in Cultured DRG neurons%多巴胺增强培养新生大鼠DRG神经元ATP激活电流

    Institute of Scientific and Technical Information of China (English)

    熊顺华; 魏劲波; 王明江


    目的:探讨多巴胺对ATP激活电流的调制作用。方法:实验在培养的新生大鼠脊髓背根神经节细胞上进 行,应用全细胞膜片钳技术记录出ATP和多巴胺激活的电流。结果:在被检的DRG细胞中,有62%(39/63)的神经元 对ATP和多巴胺都敏感。在预加10-8,10-7,10-6和10-5 mol/L多巴胺后,ATP的激活电流分别增加到139.7%,141. 5%,149.9%,149.1%;呈剂量依赖性。用D1的拮抗剂SCH-23390能取消此增强作用;在电极中灌注H-7(PKC,PKA抑制剂)也能取消此增强作用。结论:多巴胺对ATP激活电流的增强作用是多巴胺作用于D1受体,通过胞内第二信使,使P2X受体通道复合体胞内磷酸化所致。%Objective To explore whether or not dopamine nodulates the response mediated by P2X receptor. Methods Experiments were carried out on the DRG neurons of cultured newborn rats. ATP - and dopamine - activated currents were recorded using the whole cell patch clamp technique. Results 62 % of the measured neurons (39/63) were sensitive to both of ATP and dopamine. When the neurons were treated with dopamine prior to the apphcation of ATP, the ATP-activated current was potentiated. The effect of dopamine was dose-dependent. With dopamine concentration of 10-8, 10-7,10-6 and 10-5 mol/L, the ATP-activated current was potentiated by 139.7%, 141.5%, 149.9%, 149.1%. The potentiation can beblocked by SCH- 23390 (D1 receptor antagonist). The intracellular application of H7 (a potent inhibitor of PKC and PKA) could abohsh the potentiation of dopamine on ATP-activated current. Gonclusion The dopamine potentiaton of the ATP-activated current might be the result of intracellular phosphorylation of P2X receptor.

  8. Effects of SO2 Derivatives on Calcium Channels in DRG Neurons%二氧化硫衍生物对背根神经元钙通道的影响

    Institute of Scientific and Technical Information of China (English)

    杜正清; 王丽娟


    The effects of SO2 derivatives on L-type and N-type calcium currents in freshly isolated rat dorsal root ganglion neurons were investigated using the whole-cell configuration of the path-clamp technique. The results showed: first,it was found that 1 μmol/L SO2 derivatives could increase the amplitudes of calcium currents in a voltage-dependent manner. The average increase of high-voltage-activated calcium currents was 63.4% ±5.7% at - 10 mV. Second,the sensitivity of SO2 derivatives on channel subtypes was quantitatively estimated based on the different ratios of L-,N-,r-( non-L- and non-N-types) types expressed in total high-voltage-activated calcium channels when the corresponding selective channel blockers were applied and the calcium currents were recorded. The data showed that 1 μmol/i SO2 derivatives increased L-type current by 82.2% ,increased N-type by 95.3% ,and increased residual r type Ca2+ currents by 9.4% ,which indicated that both N- and L-type Ca2+ channels were sensitive to SO,derivatives. It was suggested that SO2 derivatives could enhance both types of Ca2+ currents in dorsal root ganglion neurons and then lead to neuropathic pain.%应用全细胞膜片钳技术研究了SO2衍生物对大鼠DRG(背根神经节)神经元不同亚型钙通道的影响.结果表明,1μmol/LSO2衍生物对不同电压下的钙电流均有增大作用,在- 10 mV时可使钙电流增幅达到63.4%±5.7%.在细胞外液中加入不同亚型钙通道的阻滞剂并经过修正计算发现,1μmol/L SO2衍生物使L型钙电流增长了82.2%,N型钙电流增长了95.3%,r型(非L型、非N型)钙电流增长了9.4%,说明高阈值激活的N型和L型钙电流对SO2衍生物特别敏感,推测SO2衍生物诱发神经性疼痛,引起神经毒性,可能主要通过增大DRG神经元上N型和L型钙通道发生电流介导.

  9. An Optimized Culture Method of Rat Dorsal Root Ganglion Neurons

    Institute of Scientific and Technical Information of China (English)

    LIUYin; CHENJing-Hong; GONGZe-Hui


    AIM: To establish a primary culture technique of acutely isolated dorsal root ganglion (DRG) neurons, and provide a simple & useful in vitro model for study of analgesia. Methods: Acutely isolated dorsal root ganglion (DRG) neurons were planted and cultured; the configuration and growth characters of DRG neurons were observed through inverted microscope.





    La arborización dendrítica es requerida para la apropiada conectividad neuronal. La proteína SIRTl, es una desacetilasa de histonas dependiente de NAD+, a la cual se le asocian funciones relacionadas con el envejecimiento, longevidad y respuesta a estrés. En neuronas a la proteína SIRTl se le relaciona con la diferenciación neuronal, neurogénesis y neuroprotección. En el presente estudio, se evaluó el papel de SIRTl en el desarrollo dendrítico en cultivo de neuronas hipocampales. La sobree...

  11. The effect of niflumic acid on gamma aminobutyric acid activated current in DRG neurons%尼氟灭酸对γ-氨基丁酸激活DRG神经元电流的作用

    Institute of Scientific and Technical Information of China (English)

    李丽; 李静; 马克涛; 成洪聚; 赵磊; 汪洋; 司军强


    目的:观察尼氟灭酸(NFA)对大鼠背根神经节(DRG)神经元γ-氨基丁酸(GABA)激活电流的调制作用.方法:在新鲜分离的大鼠DRG神经元,应用全细胞膜片钳技术记录NFA和GABA激活电流.结果:部分DRG神经元(21/48,43.75%)外加NFA(0.1~100 μmol/L)能引起浓度依赖性的外向电流,而大多数DRG神经元(150/159,94.32%)外加GABA(0.1~100 μmol/L)则引起明显的浓度依赖性的内相电流.NFA-(100μmol/L)和GABA-(100μmol/L)激活电流的幅值分别是(0.27±0.06) nA (n=12)和(1.29±0.72)nA(n=53).然而,预使用NFA (0.1 ~ 100μmol/L)能明显的抑制GABAA受体介导的内向电流.NFA的这一抑制作用也具有明显的浓度依赖性.但NFA没有改变GABA激活内向电流的EC50(大约30 μmol/L)和翻转电位(大约-10 mV)(P> 0.05).结论:预加NFA对GABA激活电流的峰值有明显的浓度依赖性的抑制作用.

  12. Activation of nuclear factor-kappa B via endogenous tumor necrosis factor alpha regulates survival of axotomized adult sensory neurons

    NARCIS (Netherlands)

    Fernyhough, P; Smith, DR; Schapansky, J; Van Der Ploeg, R; Gardiner, NJ; Tweed, CW; Kontos, A; Freeman, L; Purves-Tyson, TD; Glazner, GW


    Embryonic dorsal root ganglion (DRG) neurons die after axonal damage in vivo, and cultured embryonic DRG neurons require exogenous neurotrophic factors that activate the neuroprotective transcription factor nuclear factor-kappaB(NF-kappaB) for survival. In contrast, adult DRG neurons survive permane

  13. Bis(7)-tacrine/tacrine对大鼠DRG神经元延时整流钾通道电流的调制作用%Inhibitory effect of Bis(7)-tacrine/tacrine on delayed rectified potassium currents in rat DRG neurons

    Institute of Scientific and Technical Information of China (English)

    李享元; 李之望


    目的 研究乙酰胆碱酯酶抑制剂bis(7)-tacrine/tacrine[bis(7)-tetrahydroaminacrine]对大鼠DRG神经元的延时整流钾通道电流的调制作用.方法 在急性分离的DRG神经元标本上,采用全细胞膜片钳技术记录钾通道电流,研究bis(7)-tacrine/tacrine对DRG神经元延时整流钾通道电流的影响和作用.结果 bis(7)-tacrine对延迟整流钾通道电流IDR具有浓度依赖性的抑制作用,其半量效浓度为(IC50)(0.72±0.05)μmol*L-1,而tacrine抑制的半量效浓度(IC50)(58.3±3.7)μmol*L-1.结论 两种药物对DRG延时整流钾通道电流有浓度依赖性的抑制作用,bis(7)-tacrine的抑制强度高一个数量级,有利于抑制神经元的钾通道过于激活和兴奋,预防胞内钾离子过度丢失而引起的神经元凋亡,起到神经保护的作用.%Aim To investigate modulatory effect of bis ( 7 )-tacrine [ bis ( 7 )-tetrahydroaminacrine ], a novel dimeric AChE inhibitor, on rat DRG delayed rectified potassium channels. Methods Experiments were per -formed on neurons acutely isolated from rat dorsal root ganglion ( DRG ) potassium channels, and the delayed rectified currents ( IDR ) were recorded with whole-cell patch clamp technique. Results IDR were inhibited by bis( 7 )-tacrine, which were much more potent ( IC50 = 0. 72 ±0. 05 μmol · L-1 for IDR ) than those by tacrine ( IC50 =58. 3 ± 3. 7 μmol · L-1 for IDR ). bis( 7 )-tac-rine ( 1 μmol · L-1 ) shifts steady state activation curve and inactivation curve of IDR to the hyperpolar-izing direction. Conclusions The inhibitory effect of bis( 7 )-tacrine on IDR may be attributed to reduction of potential ranges of steady state activation and inactivation and delay of decay phase. Drugs may prevent loss of potassium ions and excitory toxicosis for neuron, and may be neuroprotective in A. D treatment.

  14. Qualité et DRG : mariage impossible ?


    Lopes, Susana


    Les DRG, Diagnosis Related Groups, sont une classification permettant de regrouper les hospitalisations de soins aigus en fonction des affections traitées et des coûts engendrés. Ils ont été développes dans les années 70 à l'université de Yale aux Etats-Unis par le professeur Robert Fetter dans le but de standardiser les clientèles hospitalières dans un objectif de contrôle qualité. En Suisse, le financement en APDRG a commencé comme un projet pilote à Lausanne en 2002. Ce dernier a été re...

  15. Investigating DRG cost weights for hospitals in middle income countries. (United States)

    Ghaffari, Shahram; Doran, Christopher; Wilson, Andrew; Aisbett, Chris; Jackson, Terri


    Identifying the cost of hospital outputs, particularly acute inpatients measured by Diagnosis Related Groups (DRGs), is an important component of casemix implementation. Measuring the relative costliness of specific DRGs is useful for a wide range of policy and planning applications. Estimating the relative use of resources per DRG can be done through different costing approaches depending on availability of information and time and budget. This study aims to guide costing efforts in Iran and other countries in the region that are pursuing casemix funding, through identifying the main issues facing cost finding approaches and introducing the costing models compatible with their hospitals accounting and management structures. The results show that inadequate financial and utilisation information at the patient's level, poorly computerized 'feeder systems'; and low quality data make it impossible to estimate reliable DRGs costs through clinical costing. A cost modelling approach estimates the average cost of 2.723 million Rials (Iranian Currency) per DRG. Using standard linear regression, a coefficient of 0.14 (CI = 0.12-0.16) suggests that the average cost weight increases by 14% for every one-day increase in average length of stay (LOS).We concluded that calculation of DRG cost weights (CWs) using Australian service weights provides a sensible starting place for DRG-based hospital management; but restructuring hospital accounting systems, designing computerized feeder systems, using appropriate software, and development of national service weights that reflect local practice patterns will enhance the accuracy of DRG CWs.

  16. Whiplash-like facet joint loading initiates glutamatergic responses in the DRG and spinal cord associated with behavioral hypersensitivity (United States)

    Dong, Ling; Quindlen, Julia C.; Lipschutz, Daniel E.; Winkelstein, Beth A.


    The cervical facet joint and its capsule are a common source of neck pain from whiplash. Mechanical hyperalgesia elicited by painful facet joint distraction is associated with spinal neuronal hyperexcitability that can be induced by transmitter/receptor systems that potentiate the synaptic activation of neurons. This study investigated the temporal response of a glutamate receptor and transporters in the dorsal root ganglia (DRG) and spinal cord. Bilateral C6/C7 facet joint distractions were imposed in the rat either to produce behavioral sensitivity or without inducing any sensitivity. Neuronal metabotropic glutamate receptor-5 (mGluR5) and protein kinase C-epsilon (PKCε) expression in the DRG and spinal cord were evaluated on days 1 and 7. Spinal expression of a glutamate transporter, excitatory amino acid carrier 1 (EAAC1), was also quantified at both time points. Painful distraction produced immediate behavioral hypersensitivity that was sustained for 7 days. Increased expression of mGluR5 and PKCε in the DRG was not evident until day 7 and only following painful distraction; this increase was observed in small-diameter neurons. Only painful facet joint distraction produced a significant increase (p<0.001) in neuronal mGluR5 over time, and this increase also was significantly elevated (p ≤ 0.05) over responses in the other groups at day 7. However, there were no differences in spinal PKCε expression on either day or between groups. Spinal EAAC1 expression was significantly increased (p<0.03) only in the nonpainful groups on day 7. Results from this study suggest spinal glutamatergic plasticity is selectively modulated in association with facet-mediated pain. PMID:22578356

  17. 97. German Roentgen congress of the DRG. Program with abstracts; 97. Deutscher Roentgenkongress der DRG. Vollstaendiges Programm mit Abstracts

    Energy Technology Data Exchange (ETDEWEB)



    The Volume with program and abstracts of the 97. German Roentgen congress of the DRG covers the following issues: The future of radiology - where are we heading? Cardiovascular imaging - the future; brain imaging - the essentials; chest imaging - not only nodules; abdominal imaging - the liver and beyond; muscoskeletal imaging - joints and bones; head and neck radiology - made easy.

  18. 42 CFR 412.10 - Changes in the DRG classification system. (United States)


    ... 42 Public Health 2 2010-10-01 2010-10-01 false Changes in the DRG classification system. 412.10... § 412.10 Changes in the DRG classification system. (a) General rule. CMS issues changes in the DRG classification system in a Federal Register notice at least annually. Except as specified in paragraphs (c)...

  19. Effects of Electroacupuncture on the Pain Threshold and the NMDA R1 mRNA in DRG on Neuropathic Pain Rats

    Institute of Scientific and Technical Information of China (English)

    陈文玲; 杨珺; 施静; 刘晓春; 关新民


    Summary: To observe the effect of multiple electroacupuncture (EA) on the pain threshold and theregulation of N-methyl-D-aspartate (NMDA) receptor in dorsal root ganglia (DRG) of neuropathicpain rats. Rats were prepared with a unilateral chronic constriction injury (CCI) to the sciatic nerve.EA was done in acupoints "Huan Tiao" and "Yang Ling Quan" for 30 min every day and the thermalthresholds were detected after EA at 3, 5, 7, 10, 14 days after operation. On day 14 after nerve in-jury, the in situ hybridization method was used to investigate the change of NMDA R1 mRNA inL4-L5 DRG. The thermal threshold reduced significantly from day 3 after operation in CCI rats.After multiple EA treatment, the ipsilateral thermal hyperalgesia relieved gradually and the thermalthreshold had no difference with control side after day 5 (P>0. 05). From Day 7 after operation, thethermal threshold at each time point were significantly different compared with CCI group respective-ly(P>0. 05). Moreover the EA had accumulative effect. On Day 14 after operation , the NMDAR1mRNA positive neurons and the mean optic density in ipsilateral L4-5 DRG were less than that ofcontrol side(P<0. 05), mainly in medium and small neurons. After EA treatment, the NMDAR1mRNA positive neurons in ipsilateral DRG had no considerable difference comparing with those ofcontrol side , significantly increased comparing with CCI group(P<0. 05). It's concluded that theNMDA receptors in DRG relate closely with the generation and development of neuropathic pain.The multiple EA treatment can attenuate the thermal hyperlgesia of neuropathic pain rats and regu-late the NMDA receptor.

  20. Diagnosis-Related Groups (DRG and Hospital Business Performance Management

    Directory of Open Access Journals (Sweden)

    Szynkiewicz Piotr


    Full Text Available The goal of this article is to present the possibility of using Diagnosis- Related Groups (DRG in the hospital management process and to analyse the need for business performance management on the part of hospital management staff. The following research methods were used: literature analysis, case studies, and poll analysis. It is not possible to increase the effectiveness of operation of healthcare entities without increasing the importance of IT systems and using DRG more effectively in the management process. Training users in IT and the use of DRGs is important to achieving hospital effectiveness. The increased importance of analyses and planning in a hospital should be reflected in the organisational structure of service providers. Hospital controllers should have a similar role to those present in most companies in other industries.

  1. G protein-coupled inwardly rectifying potassium channels in dorsal root ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    Xiao-fei GAO; Hai-lin ZHANG; Zhen-dong YOU; Chang-lin LU; Cheng HE


    Aim: G protein-coupled inwardly rectifying potassium channels (GIRK) are important for neuronal signaling and membrane excitability. In the present study, we intend to find whether GIRK channels express functionally in adult rat dorsal root ganglion (DRG) neurons. Methods: We used RT-PCR to detect mRNA for4 subunits of GIRK in the adult DRG. The whole-cell patch clamp recording was used to confirm GIRK channels functionally expressed. Results: The mRNA for the 4 subunits of GIRK were detected in the adult DRG. GTPγS enhanced inwardly rectifying potassium (K+) currents of the DRG neurons, while Ba2+inhibited such currents. Furthermore, the GIRK channels were shown to be coupled to the GABAB receptor, a member of the G protein-coupled receptor family, as baclofen increased the inwardly rectifying K+ currents. Conclusion: GIRK channels are expressed and functionally coupled with GABAB receptors in adult rat DRG neurons.

  2. The fluorescent pentameric oligothiophene pFTAA identifies filamentous tau in live neurons cultured from adult P301S tau mice

    Directory of Open Access Journals (Sweden)

    Aviva eTolkovsky


    Full Text Available Identification of fluorescent dyes that label filamentous protein aggregates characteristic of neurodegenerative disease, such as β-amyloid and tau in Alzheimer’s disease (AD, in a live cell culture system has previously been a major hurdle. Here we show that pentameric formyl thiophene acetic acid (pFTAA fulfils this function in living neurons cultured from adult P301S tau transgenic mice. Injection of pFTAA into 5-month-old P301S tau mice detected cortical and DRG neurons immunoreactive for AT100, which identifies solely filamentous tau, or MC1, which identifies a conformational change in tau that is commensurate with neurofibrillary tangle formation in AD brains. In fixed cultures of dorsal root ganglion (DRG neurons, pFTAA binding, which also identified AT100 or MC1+ve neurons, followed a single, saturable binding curve with a half saturation constant of 0.14 µM, the first reported measurement of a binding affinity of a beta-sheet reactive dye to primary neurons harbouring filamentous tau. Treatment with formic acid, which solubilises filamentous tau, extracted pFTAA, and prevented the re-binding of pFTAA and MC1 without perturbing expression of soluble tau, detected using an anti-human tau (HT7 antibody. In live cultures, pFTAA only identified DRG neurons that, after fixation, were AT100/MC1+ve, confirming that these forms of tau pre-exist in live neurons. The utility of pFTAA to discriminate between living neurons containing filamentous tau from other neurons is demonstrated by showing that more pFTAA+ve neurons die than pFTAA-ve neurons over 25 days. Since pFTAA identifies fibrillar tau and other misfolded proteins in living neurons in culture, in animal models of several neurodegenerative diseases, and in human brains, it should have considerable application in sorting out disease mechanisms and in identifying disease-modifying drugs that will ultimately help establish the mechanisms of neurodegeneration in human neurodegenerative

  3. 96. German Roentgen congress of the DRG. Program with abstracts; 96. Deutscher Roentgenkongress der DRG. Vollstaendiges Program mit Abstracts

    Energy Technology Data Exchange (ETDEWEB)



    The volume contains the program and the abstracts of the 96th German Roentgen congress of the DRG covering the following issues: profession and environment caused diseases, medical imaging - image processing - software, experimental radiology, whole-body diagnostics, gastro- and abdomen diagnostics, vascular diagnostics, device technology, heart diagnostics, interventional radiology (vascular diseases, oncology, others), pediatric radiology, contrast agents, head- and neck diagnostics, molecular imaging, musco-skeletal diagnostics, neuroradiology, emergency diagnostics - intensive care, oncologic imaging, quality management, radiation protection, thorax diagnostics.

  4. Postembryonic neuronal addition in Zebrafish dorsal root ganglia is regulated by Notch signaling

    Directory of Open Access Journals (Sweden)

    McGraw Hillary


    Full Text Available Abstract Background The sensory neurons and glia of the dorsal root ganglia (DRG arise from neural crest cells in the developing vertebrate embryo. In mouse and chick, DRG formation is completed during embryogenesis. In contrast, zebrafish continue to add neurons and glia to the DRG into adulthood, long after neural crest migration is complete. The molecular and cellular regulation of late DRG growth in the zebrafish remains to be characterized. Results In the present study, we use transgenic zebrafish lines to examine neuronal addition during postembryonic DRG growth. Neuronal addition is continuous over the period of larval development. Fate-mapping experiments support the hypothesis that new neurons are added from a population of resident, neural crest-derived progenitor cells. Conditional inhibition of Notch signaling was used to assess the role of this signaling pathway in neuronal addition. An increase in the number of DRG neurons is seen when Notch signaling is inhibited during both early and late larval development. Conclusions Postembryonic growth of the zebrafish DRG comes about, in part, by addition of new neurons from a resident progenitor population, a process regulated by Notch signaling.

  5. Effects of BmK AS-1 on TTX-R Sodium Channel Currents in Rat DRG Neurons%东亚钳蝎毒素多肽纯化组份BmK AS-1对大鼠背根神经节神经元河豚毒素不敏感型钠通道电流的作用

    Institute of Scientific and Technical Information of China (English)

    毛霞; 肖杭; 谭智勇; 石云; 赵志奇; 吉永华


    目的研究国产东亚钳蝎(Buthus martensi Karsch, BmK)毒素多肽的纯化单体组份BmK AS-1对大鼠背根神经节(DRG)神经元河豚毒素不敏感(TTX-R)钠电流的作用.方法采用膜片箝全细胞记录方法,观察BmK AS-1对单个DRG细胞TTX-R钠电流幅值的影响.结果 BmK AS-1剂量依赖地抑制TTX-R钠电流,且高剂量(10 μg/ml)BmK AS-1几乎完全抑制TTX-R钠电流,其抑制作用不可逆.结论 BmK AS-1显著抑制TTX-R钠电流,这种抑制作用可能是其镇痛作用的机理之一.

  6. [Effect of spontaneous firing of injured dorsal root ganglion neuron on excitability of wide dynamic range neuron in rat spinal dorsal horn]. (United States)

    Song, Ying; Zhang, Yong-Mei; Xu, Jie; Wu, Jing-Ru; Qin, Xia; Hua, Rong


    The aim of the paper is to study the effect of spontaneous firing of injured dorsal root ganglion (DRG) neuron in chronic compression of DRG (CCD) model on excitability of wide dynamic range (WDR) neuron in rat spinal dorsal horn. In vivo intracellular recording was done in DRG neurons and in vivo extracellular recording was done in spinal WDR neurons. After CCD, incidence of spontaneous discharge and firing frequency enhanced to 59.46% and (4.30 ± 0.69) Hz respectively from 22.81% and (0.60 ± 0.08) Hz in normal control group (P neuron in CCD rats decreased the spontaneous activities of WDR neurons from (191.97 ± 45.20)/min to (92.50 ± 30.32)/min (P neuron evoked spontaneous firing in a reversible way (n = 5) in silent WDR neurons of normal rats. There was 36.36% (12/33) WDR neuron showing after-discharge in response to innocuous mechanical stimuli on cutaneous receptive field in CCD rats, while after-discharge was not seen in control rats. Local administration of TTX on DRG with a concentration of 50 nmol/L attenuated innocuous electric stimuli-evoked after-discharge of WDR neurons in CCD rats in a reversible manner, and the frequency was decreased from (263 ± 56.5) Hz to (117 ± 30) Hz (P neurons is influenced by spontaneous firings of DRG neurons after CCD.

  7. Characterization of Na+ and Ca2+ channels in zebrafish dorsal root ganglion neurons.

    Directory of Open Access Journals (Sweden)

    Yu-Jin Won

    Full Text Available BACKGROUND: Dorsal root ganglia (DRG somata from rodents have provided an excellent model system to study ion channel properties and modulation using electrophysiological investigation. As in other vertebrates, zebrafish (Danio rerio DRG are organized segmentally and possess peripheral axons that bifurcate into each body segment. However, the electrical properties of zebrafish DRG sensory neurons, as compared with their mammalian counterparts, are relatively unexplored because a preparation suitable for electrophysiological studies has not been available. METHODOLOGY/PRINCIPAL FINDINGS: We show enzymatically dissociated DRG neurons from juvenile zebrafish expressing Isl2b-promoter driven EGFP were easily identified with fluorescence microscopy and amenable to conventional whole-cell patch-clamp studies. Two kinetically distinct TTX-sensitive Na(+ currents (rapidly- and slowly-inactivating were discovered. Rapidly-inactivating I(Na were preferentially expressed in relatively large neurons, while slowly-inactivating I(Na was more prevalent in smaller DRG neurons. RT-PCR analysis suggests zscn1aa/ab, zscn8aa/ab, zscn4ab and zscn5Laa are possible candidates for these I(Na components. Voltage-gated Ca(2+ currents (I(Ca were primarily (87% comprised of a high-voltage activated component arising from ω-conotoxin GVIA-sensitive Ca(V2.2 (N-type Ca(2+ channels. A few DRG neurons (8% displayed a miniscule low-voltage-activated component. I(Ca in zebrafish DRG neurons were modulated by neurotransmitters via either voltage-dependent or -independent G-protein signaling pathway with large cell-to-cell response variability. CONCLUSIONS/SIGNIFICANCE: Our present results indicate that, as in higher vertebrates, zebrafish DRG neurons are heterogeneous being composed of functionally distinct subpopulations that may correlate with different sensory modalities. These findings provide the first comparison of zebrafish and rodent DRG neuron electrical properties and

  8. Global transcriptional programs in peripheral nerve endoneurium and DRG are resistant to the onset of type 1 diabetic neuropathy in Ins2 mice.

    Directory of Open Access Journals (Sweden)

    Anne-Sophie de Preux Charles

    Full Text Available While the morphological and electrophysiological changes underlying diabetic peripheral neuropathy (DPN are relatively well described, the involved molecular mechanisms remain poorly understood. In this study, we investigated whether phenotypic changes associated with early DPN are correlated with transcriptional alterations in the neuronal (dorsal root ganglia [DRG] or the glial (endoneurium compartments of the peripheral nerve. We used Ins2(Akita/+ mice to study transcriptional changes underlying the onset of DPN in type 1 diabetes mellitus (DM. Weight, blood glucose and motor nerve conduction velocity (MNCV were measured in Ins2(Akita/+ and control mice during the first three months of life in order to determine the onset of DPN. Based on this phenotypic characterization, we performed gene expression profiling using sciatic nerve endoneurium and DRG isolated from pre-symptomatic and early symptomatic Ins2(Akita/+ mice and sex-matched littermate controls. Our phenotypic analysis of Ins2(Akita/+ mice revealed that DPN, as measured by reduced MNCV, is detectable in affected animals already one week after the onset of hyperglycemia. Surprisingly, the onset of DPN was not associated with any major persistent changes in gene expression profiles in either sciatic nerve endoneurium or DRG. Our data thus demonstrated that the transcriptional programs in both endoneurial and neuronal compartments of the peripheral nerve are relatively resistant to the onset of hyperglycemia and hypoinsulinemia suggesting that either minor transcriptional alterations or changes on the proteomic level are responsible for the functional deficits associated with the onset of DPN in type 1 DM.

  9. Hospital Coding Practice, Data Quality, and DRG-Based Reimbursement under the Thai Universal Coverage Scheme (United States)

    Pongpirul, Krit


    In the Thai Universal Coverage scheme, hospital providers are paid for their inpatient care using Diagnosis Related Group (DRG) reimbursement. Questionable quality of the submitted DRG codes has been of concern whereas knowledge about hospital coding practice has been lacking. The objectives of this thesis are (1) To explore hospital coding…

  10. The impact of DRG reimbursement on strategic planning. (United States)

    Zuckerman, A M


    DRG reimbursement has been in effect in New Jersey since 1980 and has resulted in significant changes in the way hospitals conduct strategic planning. These effects are identified and categorized according to how they have changed the process, the participants and the products of strategic planning. Strategic planning under DRGs increasingly focuses on market segmentation, competitive position analysis, strategic business units and financial simulation. More significant roles in the process are assumed by physicians, community, chief financial officers and data sources. Planning strategies emphasize marketing, unbundling and vertical and horizontal integration. Strategic planning is moving toward more detailed market and financial analyses, including the measurement of the financial impact of physician performance on the hospital and subsequent modification of physician practices.

  11. Visualizing sensory transmission between dorsal root ganglion and dorsal horn neurons in co-culture with calcium imaging. (United States)

    Ohshiro, Hiroyuki; Ogawa, Shinji; Shinjo, Katsuhiro


    Sensory information is conveyed to the central nervous system by primary afferent neurons within dorsal root ganglia (DRG), which synapse onto neurons of the dorsal horn of the spinal cord. This synaptic connection is central to the processing of both sensory and pain stimuli. Here, we describe a model system to monitor synaptic transmission between DRG neurons and dorsal horn neurons that is compatible with high-throughput screening. This co-culture preparation comprises DRG and dorsal horn neurons and utilizes Ca(2+) imaging with the indicator dye Fura-2 to visualize synaptic transmission. Addition of capsaicin to co-cultures stimulated DRG neurons and led to activation of dorsal horn neurons as well as increased intracellular Ca(2+) concentrations. This effect was dose-dependent and absent when DRG neurons were omitted from the culture. NMDA receptors are a critical component of synapses between DRG and dorsal horn neurons as MK-801, a use-dependent non-competitive antagonist, prevented activation of dorsal horn neurons following capsaicin treatment. This model system allows for rapid and efficient analysis of noxious stimulus-evoked Ca(2+) signal transmission and provides a new approach both for investigating synaptic transmission in the spinal cord and for screening potential analgesic compounds.


    Institute of Scientific and Technical Information of China (English)

    田镇溥; 王洋; 张文雯; 王艳萍; 马克涛; 李丽; 司军强


    目的:观察尼氟灭酸(niflumic acid,NFA)干预后,TMEM 16A在坐骨神经压榨性损伤(chronic constriction injury,CCI)模型鼠背根神经节(dorsal root ganglion,DRG)神经元上的表达,研究TMEM16A是否参与神经病理性疼痛.方法:制备CCI模型,热板实验检测热缩足反射潜伏期(thermalwithdrawal latency,TWL).在模型制备后第ld开始以腹腔注射形式给予不同浓度的NFA干预14d,取大鼠L4~6 DRG神经元进行实验.免疫荧光实验明确TMEM16A在DRG神经元中的分布;运用RT-PCR技术和Westem Blot技术在给予不同浓度NFA干预后,检测CCI模型DRG神经元上TMEM 16A的mRNA水平和蛋白的表达.结果:(1) CCI组的TWL较正常组明显缩短,给予10 μM、50 μM和300 μM的NFA干预后,各组TWL较CCI组均明显延长(P<0.01,刀=6);50μM的NFA干预组较10 μM的NFA干预组TWL也明显延长(P<0.05,n=6);但300 μM的NFA干预组与50 μM的NFA干预组相比,TWL时间差异无统计学意义. (2)免疫荧光显示TMEM16A主要存在于DRG神经元上;(3) CCI组mRNA水平较正常组明显增高;随着NFA浓度的增加,DRG神经元TMEM 16A的mRNA水平较CCI组逐渐降低,差异具有统计学意义(P< 0.01,n=6). (4) CCI组TMEM16A蛋白表达较正常组的明显增高;随着NFA浓度的增加,DRG神经元上TMEM16A蛋白表达较CCI组逐渐减低,差异具有统计学意义(P< 0.01,n=6).结论:尼氟灭酸能抑制神经病理性疼痛大鼠DRG神经元TMEM16A的表达,而且与尼氟灭酸的剂量相关,提示钙激活氯通道可能参与或调控神经病理性疼痛的发生.

  13. Slack and Slick Kna channels are required for the depolarizing afterpotential of acutely isolated, medium diameter rat dorsal root ganglion neu-rons

    Institute of Scientific and Technical Information of China (English)

    Shang-bang GAO; Ying WU; Cai-xia L(U); Zhao-hua GUO; Chen-hong LI; Jiu-ping DING


    Aim: Na+-activated K+ (Kna) channels set and stabilize resting membrane poten- tial in rat small dorsal root ganglion (DRG) neurons. However, whether Kna chan- nels play the same role in other size DRG neurons is still elusive. The aim of this study is to identify the existence and potential physiological functions of Kna channels in medium diameter (25-35 μm) DRG neurons. Methods: Inside-out and whole-cell patch-clamp were used to study the electrophysiological characteriza- tions of native Kna, channels. RT-PCR was used to identify the existence of Slack and Slick genes. Results: We report that Kna channels are required for depolariz- ing afterpotential (DAP) in medium sized rat DRG neurons. In inside-out patches, Ks, channels represented 201 pS unitary chord conductance and were activated by cytoplasmic Na+ [the half maximal effective concentration (EC50): 35 mmol/L] in 160 mmol/L symmetrical K+/K+ solution. Additionally, these Kna channels also represented cytoplasmic Cl--dependent activation. RT-PCR confirmed the exist- ence of Slack and Slick genes in DRG neurons. Tetrodotoxin (TTX, 100 nmol/L) completely blocked the DRG inward Na+ currents, and the following outward cur- rents which were thought to be Kna currents. The DAP was increased when extracellular Na+ was replaced by Li+. Conclusion: We conclude that Slack and Slick Kna channels are required for DAP of medium diameter rat DRG neurons that regulate DRG action potential repolarization.

  14. Rabbit IgG distribution in skin, spinal cord and DRG following systemic injection in rat. (United States)

    Tonra, J R; Mendell, L M


    In order to determine the distribution of antibodies such as anti-NGF following systemic injection in neonates, immunocytochemical techniques were used to examine the localization of rabbit IgG in rat skin, DRG, and spinal cord after treatments with normal rabbit serum or purified rabbit IgG. Daily subcutaneous injections beginning on postnatal day 2 or on day 15 were given for three days. On the fourth day the animals were sacrificed and tissues were processed for rabbit IgG-IR. In the dorsal and ventral spinal cord, staining intensities suggest a substantial increase in the blood-brain barrier during the first two weeks after birth. Staining intensity in the epidermis of the glabrous skin from the hindpaw was substantially lower than in the adjacent dermis. In addition, IgG infrequently accumulated intracellularly in intensely stained patches in the epidermis. IgG was also able to reach relatively high intracellular concentrations in a small number of sensory neurons. The IgG staining pattern in the skin was similar when anti-NGF itself was administered to the animals. The results are discussed in the context of the effects of anti-NGF on the development of nociceptive afferents.

  15. Tetrodotoxin-resistant sodium channels in sensory neurons generate slow resurgent currents that are enhanced by inflammatory mediators. (United States)

    Tan, Zhi-Yong; Piekarz, Andrew D; Priest, Birgit T; Knopp, Kelly L; Krajewski, Jeffrey L; McDermott, Jeff S; Nisenbaum, Eric S; Cummins, Theodore R


    Resurgent sodium currents contribute to the regeneration of action potentials and enhanced neuronal excitability. Tetrodotoxin-sensitive (TTX-S) resurgent currents have been described in many different neuron populations, including cerebellar and dorsal root ganglia (DRG) neurons. In most cases, sodium channel Nav1.6 is the major contributor to these TTX-S resurgent currents. Here we report a novel TTX-resistant (TTX-R) resurgent current recorded from rat DRG neurons. The TTX-R resurgent currents are similar to classic TTX-S resurgent currents in many respects, but not all. As with TTX-S resurgent currents, they are activated by membrane repolarization, inhibited by lidocaine, and enhanced by a peptide-mimetic of the β4 sodium channel subunit intracellular domain. However, the TTX-R resurgent currents exhibit much slower kinetics, occur at more depolarized voltages, and are sensitive to the Nav1.8 blocker A803467. Moreover, coimmunoprecipitation experiments from rat DRG lysates indicate the endogenous sodium channel β4 subunits associate with Nav1.8 in DRG neurons. These results suggest that slow TTX-R resurgent currents in DRG neurons are mediated by Nav1.8 and are generated by the same mechanism underlying TTX-S resurgent currents. We also show that both TTX-S and TTX-R resurgent currents in DRG neurons are enhanced by inflammatory mediators. Furthermore, the β4 peptide increased excitability of small DRG neurons in the presence of TTX. We propose that these slow TTX-R resurgent currents contribute to the membrane excitability of nociceptive DRG neurons under normal conditions and that enhancement of both types of resurgent currents by inflammatory mediators could contribute to sensory neuronal hyperexcitability associated with inflammatory pain.

  16. Intrathecal administration of rapamycin inhibits the phosphorylation of DRG Nav1.8 and attenuates STZ-induced painful diabetic neuropathy in rats. (United States)

    He, Wan-You; Zhang, Bin; Xiong, Qing-Ming; Yang, Cheng-Xiang; Zhao, Wei-Cheng; He, Jian; Zhou, Jun; Wang, Han-Bing


    The mammalian target of rapamycin (mTOR) is a key regulator of mRNA translation and protein synthesis, and it is specifically inhibited by rapamycin. In chronic pain conditions, mTOR-mediated local protein synthesis is crucial for neuronal hyperexcitability and synaptic plasticity. The tetrodotoxin-resistant (TTX-R) sodium channel Nav1.8 plays a major role in action potential initiation and propagation and cellular excitability in DRG (dorsal root ganglion) neurons. In this study, we investigated if mTOR modulates the phosphorylation of Nav1.8 that is associated with neuronal hyperexcitability and behavioral hypersensitivity in STZ-induced diabetic rats. Painful diabetic neuropathy (PDN) was induced in Sprague-Dawley rats by intraperitoneal injection with streptozotocin (STZ) at 60mg/kg. After the onset of PDN, the rats received daily intrathecal administrations of rapamycin (1μg, 3μg, or 10μg/day) for 7 days; other diabetic rats received the same volumes of dimethyl sulfoxide (DMSO). Herein, we demonstrate a marked increase in protein expression of total mTOR and phospho-mTOR (p-mTOR) together with the up-regulation of phosphor-Nav1.8 (p-Nav1.8) prior to the mechanical withdrawal threshold reaching a significant reduction in dorsal root ganglions (DRGs). Furthermore, the intrathecal administration of rapamycin, inhibiting the activity of mTOR, suppressed the phosphorylation of DRG Nav1.8, reduced the TTX-R current density, heightened the voltage threshold for activation and lowered the voltage threshold for inactivation and relieved mechanical hypersensitivity in diabetic rats. An intrathecal injection (i.t.) of rapamycin inhibited the phosphorylation and enhanced the functional availability of DRG Nav1.8 attenuated STZ-induced hyperalgesia. These results suggest that rapamycin is a potential therapeutic intervention for clinical PDN.

  17. Topographic Digital Raster Graphics, USGS DRG's; reprojected to state plane, Published in 2006, Washoe County. (United States)

    NSGIC GIS Inventory (aka Ramona) — This Topographic Digital Raster Graphics dataset, was produced all or in part from Hardcopy Maps information as of 2006. It is described as 'USGS DRG's; reprojected...

  18. 42 CFR 412.517 - Revision of LTC-DRG group classifications and weighting factors. (United States)


    ... SERVICES Prospective Payment System for Long-Term Care Hospitals § 412.517 Revision of LTC-DRG group... reflect changes in— (1) Treatment patterns; (2) Technology; (3) Number of discharges; and (4)...

  19. Bortezomib Treatment Produces Nocifensive Behavior and Changes in the Expression of TRPV1, CGRP, and Substance P in the Rat DRG, Spinal Cord, and Sciatic Nerve

    Directory of Open Access Journals (Sweden)

    M. Quartu


    Full Text Available To investigate neurochemical changes associated with bortezomib-induced painful peripheral neuropathy (PN, we examined the effects of a single-dose intravenous administration of bortezomib and a well-established “chronic” schedule in a rat model of bortezomib-induced PN. The TRPV1 channel and sensory neuropeptides CGRP and substance P (SP were studied in L4-L5 dorsal root ganglia (DRGs, spinal cord, and sciatic nerve. Behavioral measures, performed at the end of the chronic bortezomib treatment, confirmed a reduction of mechanical nociceptive threshold, whereas no difference occurred in thermal withdrawal latency. Western blot analysis showed a relative increase of TRPV1 in DRG and spinal cord after both acute and chronic bortezomib administration. Reverse transcriptase-polymerase chain reaction revealed a decrease of TRPV1 and CGRP mRNA relative levels after chronic treatment. Immunohistochemistry showed that in the DRGs, TRPV1-, CGRP-, and SP-immunoreactive neurons were mostly small- and medium-sized and the proportion of TRPV1- and CGRP-labeled neurons increased after treatment. A bortezomib-induced increase in density of TRPV1- and CGRP-immunoreactive innervation in the dorsal horn was also observed. Our findings show that bortezomib-treatment selectively affects subsets of DRG neurons likely involved in the processing of nociceptive stimuli and that neurochemical changes may contribute to development and persistence of pain in bortezomib-induced PN.

  20. Different requirements for GFRα2-signaling in three populations of cutaneous sensory neurons.

    Directory of Open Access Journals (Sweden)

    Jussi Kupari

    Full Text Available Many primary sensory neurons in mouse dorsal root ganglia (DRG express one or several GFRα's, the ligand-binding receptors of the GDNF family, and their common signaling receptor Ret. GFRα2, the principal receptor for neurturin, is expressed in most of the small nonpeptidergic DRG neurons, but also in some large DRG neurons that start to express Ret earlier. Previously, GFRα2 has been shown to be crucial for the soma size of small nonpeptidergic nociceptors and for their target innervation of glabrous epidermis. However, little is known about this receptor in other Ret-expressing DRG neuron populations. Here we have investigated two populations of Ret-positive low-threshold mechanoreceptors that innervate different types of hair follicles on mouse back skin: the small C-LTMRs and the large Aβ-LTMRs. Using GFRα2-KO mice and immunohistochemistry we found that, similar to the nonpeptidergic nociceptors, GFRα2 controls the cell size but not the survival of both C-LTMRs and Aβ-LTMRs. In contrast to the nonpeptidergic neurons, GFRα2 is not required for the target innervation of C-LTMRs and Aβ-LTMRs in the back skin. These results suggest that different factors drive target innervation in these three populations of neurons. In addition, the observation that the large Ret-positive DRG neurons lack GFRα2 immunoreactivity in mature animals suggests that these neurons switch their GFRα signaling pathways during postnatal development.

  1. Functional diversity and developmental changes in rat neuronal kainate receptors. (United States)

    Wilding, T J; Huettner, J E


    1. Whole-cell currents evoked by kainate and the GluR5-selective agonist (RS)-2-amino-3-(3-hydroxy-5-tertbutylisoxazol-4-yl)propanoic acid (ATPA) were used to compare the physiological properties of kainate receptors expressed by neurons from rat hippocampus, spinal cord and dorsal root ganglia. 2. In contrast to kainate, which evoked desensitizing currents with similar decay rates and steady-state components in all three cell types, responses to ATPA were distinctly different in the three cell populations. Currents evoked by ATPA displayed a significant steady-state component in hippocampal neurons, but decayed rapidly to baseline in dorsal root ganglion (DRG) cells. ATPA failed to evoke current in many of the spinal neurons. 3. ATPA caused steady-state desensitization in DRG cells with an IC50 of 41 nM. Recovery from desensitization of DRG cell receptors by ATPA was significantly slower than for any previously described agonist. In contrast, hippocampal kainate receptors recovered from desensitization by ATPA within a few seconds. 4. Half-maximal activation of kainate receptors in hippocampal neurons required 938 nM ATPA. In DRG cells treated with concanavalin A the EC50 for ATPA was 341 nM. ATPA evoked current in embryonic hippocampal neurons but with lower amplitude relative to kainate than in cultured postnatal neurons. 5. Collectively, these results highlight functional differences between neuronal kainate receptors that may reflect their distinct subunit composition and their diverse roles in synaptic transmission.

  2. Hyperexcitable neurons and altered non-neuronal cells in the compressed spinal ganglion. (United States)

    LaMotte, Robert H; Ma, Chao


    The cell body or soma in the dosal root ganglion (DRG) is normally excitable and this excitability can increase and persist after an injury of peripheral sensory neurons. In a rat model of radicular pain, an intraforaminal implantation of a rod that chronically compressed the lumbar DRG ("CCD" model) resulted in neuronal somal hyperexcitability and spontaneous activity that was accompanied by hyperalgesia in the ipsilateral hind paw. By the 5th day after onset of CCD, there was a novel upregulation in neuronal expression of the chemokine, monocyte chemoattractant protein-1 (MCP-1 or CCL2) and also its receptor, CCR2. The neurons developed, in response to topically applied MCP-1, an excitatory response that they normally do not have. CCD also activated non-neuronal cells including, for example, the endothelial cells as evidenced by angiogenesis in the form of an increased number of capillaries in the DRG after 7 days. A working hypothesis is that the CCD induced changes in neurons and non-neuronal cells that may act together to promote the survival of the injured tissue. The release of ligands such as CCL2, in addition to possibly activating nociceptive neurons (maintaining the pain), may also act to preserve injured cells in the face of ischemia and hypoxia, for example, by promoting angiogenesis. Thus, somal hyperexcitability, as often said of inflammation, may represent a double edged sword.

  3. Hyperexcitable neurons and altered non-neuronal cells in the compressed spinal ganglion

    Institute of Scientific and Technical Information of China (English)

    Robert H. LaMotte; Chao MA


    The cell body or soma in the dosal root ganglion (DRG) is normally excitable and this excitability can increase and persist after an injury of peripheral sensory neurons. In a rat model of radicular pain, an intraforaminal implantation of a rod that chronically compressed the lumbar DRG ("CCD" model) resulted in neuronal somal hyperexcitability and spontaneous activity that was accom-panied by hyperalgesia in the ipsilateral hind paw. By the 5th day after onset of CCD, there was a novel upregulation in neuronal expression of the chemokine, monocyte chemoattractant protein-1 (MCP- 1 or CCL2) and also its receptor, CCR2. The neurons developed, in response to topically applied MCP-1, an excitatory response that they normally do not have. CCD also activated non-neuronal cells including, for example, the endothelial cells as evidenced by angiogenesis in the form of an increased number of capillaries in the DRG after 7 days. A working hypothesis is that the CCD induced changes in neurons and non-neuronal cells that may act together to promote the survival of the injured tissue. The release of ligands such as CCL2, in addition to possibly activating nociceptive neurons (maintaining the pain), may also act to preserve injured cells in the face of ischemia and hypoxia, for example, by promoting angiogenesis. Thus, somal hyperexcitability, as often said of inflammation, may represent a double edged sword.

  4. Interactions between neuronal and non-neuronal cells in adult rat isolated dorsal root ganglion cells

    Institute of Scientific and Technical Information of China (English)



    Objective The glial cells of the central nervous system are involved in tripartite signaling, therefore we have been investigating the relationship between sensory neurons and non-neuronal cells in isolated preparations of dorsal root ganglia (DRG). Methods The mixed cell cultures of dissociated DRG cells were separated to yield enriched fractions of IB4-positive cells (small diameter, non-peptidergic cells), IB4-negative cells (small diameter, peptidergic cells, and large diameter cells), and non-neuronal cells (principally satellite glial cells, Schwarm cells and fibroblasts). Adenylyl cyclase activity was assayed by measuring production of [3H]cAMP from cells preloaded with [3H]adenine. Results PGE2 and the PGI2 mimetic eicaprost stimulated adenylyl cyclase activity which was inhibited by ONO-AE3-208 (EP4 antagonist) or CAY10441 (IP antagonist) with estimated pA2 values of 8.9 and 8.2, respectively. Surprisingly, both PGE2 and cicaprost-stimulated [3H] cAMP production was greatest in the non-neuronal cell preparation. Furthermore, when the number of non-neuronal cells was kept constant and the number of neuronal cells was increased, we observed a progressive decrease in prostanoid-stimulated activity. Conclusions Sensory neurons appear to regulate prostanoid receptor-mediated cell signaling in non-neuronal cells within the DRG.

  5. Caspase-Mediated Apoptosis in Sensory Neurons of Cultured Dorsal Root Ganglia in Adult Mouse

    Directory of Open Access Journals (Sweden)

    Hamid Reza Momeni


    Full Text Available Objective: Sensory neurons in dorsal root ganglia (DRG undergo apoptosis after peripheral nerve injury. The aim of this study was to investigate sensory neuron death and the mechanism involved in the death of these neurons in cultured DRG.Materials and Methods: In this experimental study, L5 DRG from adult mouse were dissected and incubated in culture medium for 24, 48, 72 and 96 hours. Freshly dissected and cultured DRG were then fixed and sectioned using a cryostat. Morphological and biochemical features of apoptosis were investigated using fluorescent staining (Propidium iodide and Hoechst 33342 and the terminal Deoxynucleotide transferase dUTP nick end labeling (TUNEL method respectively. To study the role of caspases, general caspase inhibitor (Z-VAD.fmk, 100 μM and immunohistochemistry for activated caspase-3 were used.Results: After 24, 48, 72 and 96 hours in culture, sensory neurons not only displayed morphological features of apoptosis but also they appeared TUNEL positive. The application of Z-VAD.fmk inhibited apoptosis in these neurons over the same time period. In addition, intense activated caspase-3 immunoreactivity was found both in the cytoplasm and the nuclei of these neurons after 24 and 48 hours.Conclusion: Results of the present study show caspase-dependent apoptosis in the sensory neurons of cultured DRG from adult mouse.

  6. Neurotoxicity of isoniazid and its metabolites in cultures of mouse dorsal root ganglion neurons and hybrid neuronal cell line. (United States)

    Sanfeliu, C; Wright, J M; Kim, S U


    Isoniazid (INH) is one of the anti-tuberculosis drugs widely prescribed for patients since the early 1950s. It is relatively nontoxic but some patients develop peripheral neuropathy attributed to a disturbance of vitamin B6 metabolism. Some isoniazid metabolites are hepatotoxic but little is known about their neurotoxic property. Isoniazid and its metabolites including acetylisoniazid, acetylhydrazine, diacetylhydrazine, isonicotinic acid and hydrazine were examined for their potential neurotoxic effects in cultured mouse dorsal root ganglion (DRG) neurons and mouse neuroblastoma x DRG neuron hybrid cell line N18D3. Isoniazid did not cause neurotoxicity at exposures up to 7 days. Hydrazine was found to be the most toxic metabolite with LC50 values of 2.7 mM and 0.3 mM after 7 days of exposure in DRG neurons and N18D3 hybrid neurons, respectively. Other metabolites including acetylisoniazid, acetylhydrazine, diacetylhydrazine and isonicotinic acid had moderate to minor neurotoxic effects on N18D3 hybrid neurons. Pyridoxine, which is used in clinical practice to prevent or ameliorate the isoniazid-induced neuropathy, did not consistently reverse the neurotoxicity of any of the metabolites in the cell cultures, but some interaction with hydrazine cannot be ruled out. Pyridoxine itself was found to be neurotoxic both in DRG neurons and N18D3 hybrid neurons, in agreement with human peripheral sensory neuropathy caused by prolonged overdosage. The enzymes catalase and superoxide dismutase and the antioxidant agent selenium showed some protection against hydrazine neurotoxicity, suggesting an involvement of the generation of reactive oxygen species in the pathogenesis of isoniazid neuropathy. Both mouse DRG neurons and N18D3 mouse hybrid neurons were shown to be useful culture systems for elucidating the neurotoxicity mechanisms of agents causing sensory neuropathies and general neurotoxic effects in the nervous system.

  7. Evaluation of the productivity of Brazilian hospitals by the methodology of diagnosis related group (DRG)

    CERN Document Server

    Filho, Jose Carlos Serufo; Grillo, Tania Moreira


    The management requires a hospital organization to provision their costs/expenses with tools that approximate reality. The task of measuring productivity can be complex and uncertain, several methods are tested and the use of the DRG has been efficient, being used to assess the productivity through clinical outcomes. Cross-sectional study evaluated 145.710 hospitalizations in the period 2012-2014, using the DRG methodology for measuring productivity from the median length of hospitalization. When we group all hospitalizations in clinical (37.6%) and surgical (62.4%), multiple analyzes could be made according to this criterion. The DRG as a tool for prediction of hospital days is an effective alternative, thereby contributing to the control of productivity that directly influences the costs of hospital expenses and product and service quality.

  8. Modulation of oxidative stress and Ca(2+) mobilization through TRPM2 channels in rat dorsal root ganglion neuron by Hypericum perforatum. (United States)

    Nazıroğlu, M; Çiğ, B; Özgül, C


    A main component of St. John's Wort (Hypericum perforatum, HP) is hyperforin which has antioxidant properties in dorsal root ganglion (DRG) neurons, due to its ability to modulate NADPH oxidase and protein kinase C. Recent reports indicate that oxidative stress through NADPH oxidase activates TRPM2 channels. HP may be a useful treatment for Ca(2+) entry and oxidative stress through modulation of TRPM2 channels in the DRG. We aimed to investigate the protective role of HP on Ca(2+) entry and oxidative stress through TRPM2 channels in DRG neurons of rats. The native rat DRG neurons were used in whole-cell patch-clamp, Fura-2 and antioxidant experiments. Appropriate, nontoxic concentrations and incubation times for HP were determined in the DRG neurons by assessing cell viability. The H2O2-induced TRPM2 currents were inhibited by 2-aminoethyl diphenylborinate (2-APB) and N-(p-amylcinnamoyl)anthranilic acid (ACA). TRPM2 current densities and cytosolic free Ca(2+) concentration in the neurons were also reduced by HP (2 and 24h). In Fura-2 experiments, cytosolic Ca(2+) mobilization was reduced by voltage-gated calcium channel blockers (verapamil+diltiazem, V+D) and HP. Glutathione peroxidase activity and GSH values in the DRG were high in HP, 2-APB and V+D groups although lipid peroxidation level was low in the groups. In conclusion, we observed a protective role for HP on Ca(2+) entry through a TRPM2 channel in the DRG neurons. Since over-production of oxidative stress and Ca(2+) entry are implicated in the pathophysiology of neuropathic pain and neuronal inflammation, our findings may be relevant to the etiology and treatment of neuropathology in DRG neurons.

  9. Neuronal activation by mucosal biopsy supernatants from irritable bowel syndrome patients is linked to visceral sensitivity. (United States)

    Buhner, Sabine; Braak, Breg; Li, Qin; Kugler, Eva Maria; Klooker, Tamira; Wouters, Mira; Donovan, Jemma; Vignali, Sheila; Mazzuoli-Weber, Gemma; Grundy, David; Boeckxstaens, Guy; Schemann, Michael


    Based on the discomfort/pain threshold during rectal distension, irritable bowel syndrome (IBS) patients may be subtyped as normo- or hypersensitive. We previously showed that mucosal biopsy supernatants from IBS patients activated enteric and visceral afferent neurons. We tested the hypothesis that visceral sensitivity is linked to the degree of neuronal activation. Normo- and hypersensitive IBS patients were distinguished by their discomfort/pain threshold to rectal balloon distension with a barostat. Using potentiometric and Ca(2+) dye imaging, we recorded the response of guinea-pig enteric submucous and mouse dorsal root ganglion (DRG) neurons, respectively, to mucosal biopsy supernatants from normosensitive (n = 12 tested in enteric neurons, n = 9 tested in DRG) and hypersensitive IBS patients (n = 9, tested in both types of neurons). In addition, we analysed the association between neuronal activation and individual discomfort/pain pressure thresholds. The IBS supernatants evoked Ca(2+) transients in DRG neurons and spike discharge in submucous neurons. Submucous and DRG neurons showed significantly stronger responses to supernatants from hypersensitive IBS patients as reflected by higher spike frequency or stronger [Ca(2+)]i transients in a larger proportion of neurons. The neuroindex as a product of spike frequency or [Ca(2+)]i transients and proportion of responding neurons correlated significantly with the individual discomfort/pain thresholds of the IBS patients. Supernatants from hypersensitive IBS patients caused stronger activation of enteric and DRG neurons. The level of activation correlated with the individual discomfort/pain threshold pressure values. These findings support our hypothesis that visceral sensitivity is linked to activation of peripheral neurons by biopsy supernatants.

  10. Somatosensory neuron types identified by high-coverage single-cell RNA-sequencing and functional heterogeneity. (United States)

    Li, Chang-Lin; Li, Kai-Cheng; Wu, Dan; Chen, Yan; Luo, Hao; Zhao, Jing-Rong; Wang, Sa-Shuang; Sun, Ming-Ming; Lu, Ying-Jin; Zhong, Yan-Qing; Hu, Xu-Ye; Hou, Rui; Zhou, Bei-Bei; Bao, Lan; Xiao, Hua-Sheng; Zhang, Xu


    Sensory neurons are distinguished by distinct signaling networks and receptive characteristics. Thus, sensory neuron types can be defined by linking transcriptome-based neuron typing with the sensory phenotypes. Here we classify somatosensory neurons of the mouse dorsal root ganglion (DRG) by high-coverage single-cell RNA-sequencing (10 950 ± 1 218 genes per neuron) and neuron size-based hierarchical clustering. Moreover, single DRG neurons responding to cutaneous stimuli are recorded using an in vivo whole-cell patch clamp technique and classified by neuron-type genetic markers. Small diameter DRG neurons are classified into one type of low-threshold mechanoreceptor and five types of mechanoheat nociceptors (MHNs). Each of the MHN types is further categorized into two subtypes. Large DRG neurons are categorized into four types, including neurexophilin 1-expressing MHNs and mechanical nociceptors (MNs) expressing BAI1-associated protein 2-like 1 (Baiap2l1). Mechanoreceptors expressing trafficking protein particle complex 3-like and Baiap2l1-marked MNs are subdivided into two subtypes each. These results provide a new system for cataloging somatosensory neurons and their transcriptome databases.

  11. TNF-α enhances the currents of voltage gated sodium channels in uninjured dorsal root ganglion neurons following motor nerve injury. (United States)

    Chen, Xi; Pang, Rui-Ping; Shen, Kai-Feng; Zimmermann, Manfred; Xin, Wen-Jun; Li, Yong-Yong; Liu, Xian-Guo


    The ectopic discharges observed in uninjured dorsal root ganglion (DRG) neurons following various lesions of spinal nerves have been attributed to functional alterations of voltage-gated sodium channels (VGSCs). Such mechanisms may be important for the development of neuropathic pain. However, the pathophysiology underlying the functional modulation of VGSCs following nerve injury is largely unknown. Here, we studied this issue with use of a selective lumbar 5 ventral root transection (L5-VRT) model, in which dorsal root ganglion (DRG) neurons remain intact. We found that the L5-VRT increased the current densities of TTX-sensitive Na channels as well as currents in Nav1.8, but not Nav1.9 channels in uninjured DRG neurons. The thresholds of action potentials decreased and firing rates increased in DRG neurons following L5-VRT. As we found that levels of tumor necrosis factor-alpha (TNF-α) increased in cerebrospinal fluid (CSF) and in DRG tissue after L5-VRT, we tested whether the increased TNF-α might result in the changes in sodium channels. Indeed, recombinant rat TNF (rrTNF) enhanced the current densities of TTX-S and Nav1.8 in cultured DRG neurons dose-dependently. Furthermore, genetic deletion of TNF receptor 1 (TNFR-1) in mice attenuated the mechanical allodynia and prevented the increase in sodium currents in DRG neurons induced by L5-VRT. These data suggest that the increase in sodium currents in uninjured DRG neurons following nerve injury might be mediated by over-production of TNF-α.

  12. Application of shock waves to rat skin decreases calcitonin gene-related peptide immunoreactivity in dorsal root ganglion neurons. (United States)

    Takahashi, Norimasa; Wada, Yuichi; Ohtori, Seiji; Saisu, Takashi; Moriya, Hideshige


    There have been several reports on the use of extracorporeal shock waves in the treatment of pseudarthrosis, calcifying tendinitis, and tendinopathies of the elbow. However, the pathomechanism of pain relief has not been clarified. To investigate the analgesic properties of shock wave application, we analyzed changes in calcitonin gene-related peptide (CGRP)-immunoreactive (ir) dorsal root ganglion (DRG) neurons. In the nontreated group, fluorogold-labeled dorsal root ganglion neurons innervating the most middle foot pad of hind paw were distributed in the L4 and L5 dorsal root ganglia. Of these neurons, 61% were CGRP-ir. However, in the shock wave-treated group, the percentage of FG-labeled CGRP-ir DRG neurons decreased to 18%. These data show that relief of clinical pain after shock wave application may result from reduced CGRP expression in DRG neurons.

  13. Coculture of rat embryonic proprioceptive sensory neurons and myotubes

    NARCIS (Netherlands)

    Copray, S; Liem, R; MantinghOtter, [No Value; Brouwer, N


    With the aim to study the cellular mechanisms underlying the process of muscle spindle (re)generation, dorsal root ganglia (DRG) neurons derived from 16-day rat embryos were cocultured with developing myotubes in a compartmentalized culture device. To accomplish the selective survival and neurite fo

  14. Identification of DRG-1 As a Melanoma-Associated Antigen Recognized by CD4+ Th1 Cells.

    Directory of Open Access Journals (Sweden)

    Yukiko Kiniwa

    Full Text Available Immunotherapy has emerged as a promising strategy for the treatment of metastatic melanoma. Clinical studies have demonstrated the feasibility of cancer immunotherapy using tumor antigens recognized by CD8(+ T cells. However, the overall immune responses induced by these antigens are too weak and transient to induce tumor regression in the majority of patients who received immunization. A growing body of evidence suggests that CD4(+ T helper (Th cells play an important role in antitumor immunity. Therefore, the identification of MHC class II-restricted tumor antigens capable of stimulating CD4(+ T cells may provide opportunities for developing effective cancer vaccines. To this end, we describe the identification of developmentally regulated GTP-binding protein 1 (DRG-1 as a melanoma-associated antigen recognized by HLA-DR11-restricted CD4(+ Th1 cells. Epitope mapping analysis showed that the DRG1248-268 epitope of DRG-1 was required for T cell recognition. Reverse transcription-polymerase chain reaction revealed that DRG-1 was highly expressed in melanoma cell lines but not in normal tissues. DRG-1 knockdown by lentiviral-based shRNA suppressed melanoma cell proliferation and soft agar colony formation. Taken together, these data suggest that DRG-1 plays an important role in melanoma cell growth and transformation, indicating that DRG1 may represent a novel target for CD4(+ T cell-mediated immunotherapy in melanoma.

  15. Origin and chemical coding of primary afferent neurones supplying the prostate of the dog. (United States)

    Arciszewski, M B; Zacharko, A


    Retrograde tracing technique combined with the double-fluorescent immunohistochemistry were used to investigate the distribution and chemical coding of primary afferent neurones supplying the canine prostate. After the injection of Fast Blue (FB) into the prostatic tissue retrogradely-labelled (FB(+)) primary afferent neurones were localized in bilateral L(1)-Ca(1) dorsal root ganglia (DRG). Statistical analysis using anova test showed that there are two major sources of afferent prostate innervation. The vast majority of prostate-supplying primary afferent neurones were located in bilateral L(2)-L(4) DRG (56.9 +/- 0.6%). The second source of the afferent innervation of canine prostate were bilateral S(1)-Ca(1) DRG (40.6 +/- 1.0%). No statistically significant differences were found between average number of FB(+) neurones localized in the left and right DRG (49.5 +/- 1.7 and 50.5 +/- 1.7%, respectively). Immunohistochemistry revealed that FB(+) primary afferent neurones contain several neuropeptides in various combinations. In the prostate-supplying neurones of lumbar and sacro-caudal DRG the immunoreactivity to substance P (SP) and calcitonin gene-related peptide (CGRP) was found most frequently (50 +/- 3.7 and 37.3 +/- 1.9%, respectively). Both in the lumbar and sacro-caudal DRG, considerable population of FB(+) neurones immunoreactive neither to SP nor CGRP were also found (23 +/- 2.6 and 32.8 +/- 2.3%, respectively). In the lumbar DRG 10.7 +/- 1.1% of SP-immunoreactive FB(+) neurones also contained galanin (GAL). In 9.2 +/- 2.2% of the prostate-supplying primary afferent neurones located in the sacro-caudal DRG the co-localization of SP and GAL was also reported. Results of the retrograde tracing experiment demonstrated for the first time sources of afferent innervation of the canine prostate. Double immunohistochemistry revealed that many of the prostate-supplying primary afferent neurones express some of sensory neuropeptides which presumably may be involved

  16. Lidocaine toxicity in primary afferent neurons from the rat. (United States)

    Gold, M S; Reichling, D B; Hampl, K F; Drasner, K; Levine, J D


    Evidence from both clinical studies and animal models suggests that the local anesthetic, lidocaine, is neurotoxic. However, the mechanism of lidocaine-induced toxicity is unknown. To test the hypothesis that toxicity results from a direct action of lidocaine on sensory neurons we performed in vitro histological, electrophysiological and fluorometrical experiments on isolated dorsal root ganglion (DRG) neurons from the adult rat. We observed lidocaine-induced neuronal death after a 4-min exposure of DRG neurons to lidocaine concentrations as low as 30 mM. Consistent with an excitotoxic mechanism of neurotoxicity, lidocaine depolarized DRG neurons at concentrations that induced cell death (EC50 = 14 mM). This depolarization occurred even though voltage-gated sodium currents and action potentials were blocked effectively at much lower concentrations. (EC50 values for lidocaine-induced block of tetrodotoxin-sensitive and -resistant voltage-gated sodium currents were 41 and 101 microM, respectively.) At concentrations similar to those that induced neurotoxicity and depolarization, lidocaine also induced an increase in the concentration of intracellular Ca++ ions ([Ca++]i; EC50 = 21 mM) via Ca++ influx through the plasma membrane as well as release of Ca++ from intracellular stores. Finally, lidocaine-induced neurotoxicity was attenuated significantly when lidocaine was applied in the presence of nominally Ca(++)-free bath solution to DRG neurons preloaded with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Our results indicate: 1) that lidocaine is neurotoxic to sensory neurons; 2) that toxicity results from a direct action on sensory neurons; and 3) that a lidocaine-induced increase in intracellular Ca++ is a mechanism of lidocaine-induced neuronal toxicity.

  17. Functional endothelin receptors are selectively expressed in isolectin B4-negative sensory neurons and are upregulated in isolectin B4-positive neurons by neurturin and glia-derived neurotropic factor. (United States)

    Vellani, Vittorio; Prandini, Massimiliano; Giacomoni, Chiara; Pavesi, Giorgia; Ravegnani, Laura; Magherini, Pier Cosimo


    Activation of endothelin receptors expressed in DRG neurons is functionally coupled to translocation of PKCε from cytoplasm to the plasma membrane. Using immunocytochemistry we show that in DRG cultured neurons PKCε translocation induced by endothelin-1 was prominently seen in a peptidergic subpopulation of cultured DRG neurons largely negative for isolectin B4 staining, indicating that in basal conditions functional expression of endothelin receptors does not occur in non-peptidergic, RET-expressing nociceptors. Translocation was blocked by the specific ETA-R antagonist BQ-123 while it was unaffected by the ETB-R antagonist BQ-788. No calcium response in response to endothelin-1 was observed in sensory neurons, while large and long-lasting responses were observed in the majority of non-neuronal cells present in DRG cultures, which are ensheathing Schwann cells and satellite cells, identified with the glial marker S-100. Calcium responses in non-neuronal cells were abolished by BQ-788. The fraction of peptidergic PKCε-translocated neurons was significantly increased by nerve growth factor, while in the presence of neurturin or glia-derived neurotropic factor (GDNF), an IB4-positive subpopulation of small- and medium-sized neurons showed PKCε translocation induced by endothelin-1 which could be blocked by BQ-123 but not by BQ-788. Our in vitro results show that the level of expression of functional endothelin receptors coupled to PKCε is different in peptidergic and non-peptidergic nociceptors and is modulated with different mechanisms in distinct neuronal subpopulations.

  18. The variance of length of stay and the optimal DRG outlier payments. (United States)

    Felder, Stefan


    Prospective payment schemes in health care often include supply-side insurance for cost outliers. In hospital reimbursement, prospective payments for patient discharges, based on their classification into diagnosis related group (DRGs), are complemented by outlier payments for long stay patients. The outlier scheme fixes the length of stay (LOS) threshold, constraining the profit risk of the hospitals. In most DRG systems, this threshold increases with the standard deviation of the LOS distribution. The present paper addresses the adequacy of this DRG outlier threshold rule for risk-averse hospitals with preferences depending on the expected value and the variance of profits. It first shows that the optimal threshold solves the hospital's tradeoff between higher profit risk and lower premium loading payments. It then demonstrates for normally distributed truncated LOS that the optimal outlier threshold indeed decreases with an increase in the standard deviation.

  19. Selected High Intensity Diagnosis/Procedures/DRG Workloads by States, Fiscal Year 1991 (United States)



  20. Angiotensin II type 2 receptor (AT2R) localization and antagonist-mediated inhibition of capsaicin responses and neurite outgrowth in human and rat sensory neurons


    Anand, U; Facer, P; Yiangou, Y.; Sinisi, M; Fox, M.; McCarthy, T.; Bountra, C; Korchev, YE; Anand, P


    Background The angiotensin II (AngII) receptor subtype 2 (AT2R) is expressed in sensory neurons and may play a role in nociception and neuronal regeneration. Methods We used immunostaining with characterized antibodies to study the localization of AT2R in cultured human and rat dorsal root ganglion (DRG) neurons and a range of human tissues. The effects of AngII and AT2R antagonist EMA401 on capsaicin responses in cultured human and rat (DRG) neurons were measured with calcium imaging, on neu...

  1. Are Some Neurons Hypersensitive to Metallic Nanoparticles?


    Scott, Bobby R.


    Engineered metallic nanomaterial particles (MENAP) represent a significant breakthrough in developing new products for use by consumers and industry. Skin application (e.g., via creams and sprays containing nanoparticles) may provide a key route of potential intake of MENAP and can lead to retrograde transport from nerve endings in the skin to the somatosensory neurons in dorsal root ganglia (DRG). This paper uses a novel theoretical model (stochastic threshold microdose [STM] model) to chara...

  2. Subpopulations of rat dorsal root ganglion neurons express active vesicular acetylcholine transporter. (United States)

    Tata, Ada Maria; De Stefano, M Egle; Tomassy, Giulio Srubek; Vilaró, M Teresa; Levey, Allan I; Biagioni, Stefano


    The vesicular acetylcholine transporter (VAChT) is a transmembrane protein required, in cholinergic neurons, for selective storage of acetylcholine into synaptic vesicles. Although dorsal root ganglion (DRG) neurons utilize neuropeptides and amino acids for neurotransmission, we have previously demonstrated the presence of a cholinergic system. To investigate whether, in sensory neurons, the vesicular accumulation of acetylcholine relies on the same mechanisms active in classical cholinergic neurons, we investigated VAChT presence, subcellular distribution, and activity. RT-PCR and Western blot analysis demonstrated the presence of VAChT mRNA and protein product in DRG neurons and in the striatum and cortex, used as positive controls. Moreover, in situ hybridization and immunocytochemistry showed VAChT staining located mainly in the medium/large-sized subpopulation of the sensory neurons. A few small neurons were also faintly labeled by immunocytochemistry. In the electron microscope, immunolabeling was associated with vesicle-like elements distributed in the neuronal cytoplasm and in both myelinated and unmyelinated intraganglionic nerve fibers. Finally, [(3)H]acetylcholine active transport, evaluated either in the presence or in the absence of ATP, also demonstrated that, as previously reported, the uptake of acetylcholine by VAChT is ATP dependent. This study suggests that DRG neurons not only are able to synthesize and degrade ACh and to convey cholinergic stimuli but also are capable of accumulating and, possibly, releasing acetylcholine by the same mechanism used by the better known cholinergic neurons.

  3. Electroacupuncture attenuates visceral hyperalgesia and inhibits the enhanced excitability of colon specific sensory neurons in a rat model of irritable bowel syndrome. (United States)

    Xu, G-Y; Winston, J H; Chen, J D Z


    The causes of irritable bowel syndrome remain elusive and there are few effective treatments for pain in this syndrome. Electroacupunture (EA) is used extensively for treatment of various painful conditions including chronic visceral hyperalgesia (CVH). However, mechanism of its analgesic effect remains unknown. This study was designed to investigate effect of EA on colon specific dorsal root ganglion (DRG) neurons in rats with CVH. CVH was induced by intracolonic injection of acetic acid (AA) in 10-day-old rats. Electromyography and patch clamp recordings were performed at age of 8-10 weeks. Colon DRG neurons were labelled by injection of DiI into the colon wall. EA was given at ST36 in both hindlimbs. As adults, neonatal AA-injected rats displayed an increased sensitivity to colorectal distension (CRD) and an enhanced excitability of colon DRG neurons. EA treatment for 40 min significantly attenuated the nociceptive responses to CRD in these rats; this attenuation was reversed by pretreatment with naloxone. EA treatment for 40 min per day for 5 days produced a prolonged analgesic effect and normalized the enhanced excitability of colon DRG neurons. Furthermore, in vitro application of [D-Ala(2), N-MePhe(4), Gly(5)-Ol] enkephalin (DAMGO) suppressed the enhanced excitability of colon neurons from rats with CVH. These findings suggest that EA produced-visceral analgesia, which might be mediated in a large part by endogenous opioids pathways, is associated with reversal of the enhanced excitability of colon DRG neurons in rats with CVH.

  4. Herpes Simplex Virus 1 Tropism for Human Sensory Ganglion Neurons in the Severe Combined Immunodeficiency Mouse Model of Neuropathogenesis (United States)

    Che, Xibing; Reichelt, Mike; Qiao, Yanli; Gu, Haidong; Arvin, Ann


    The tropism of herpes simplex virus (HSV-1) for human sensory neurons infected in vivo was examined using dorsal root ganglion (DRG) xenografts maintained in mice with severe combined immunodeficiency (SCID). In contrast to the HSV-1 lytic infectious cycle in vitro, replication of the HSV-1 F strain was restricted in human DRG neurons despite the absence of adaptive immune responses in SCID mice, allowing the establishment of neuronal latency. At 12 days after DRG inoculation, 26.2% of human neurons expressed HSV-1 protein and 13.1% expressed latency-associated transcripts (LAT). Some infected neurons showed cytopathic changes, but HSV-1, unlike varicella-zoster virus (VZV), only rarely infected satellite cells and did not induce fusion of neuronal and satellite cell plasma membranes. Cell-free enveloped HSV-1 virions were observed, indicating productive infection. A recombinant HSV-1-expressing luciferase exhibited less virulence than HSV-1 F in the SCID mouse host, enabling analysis of infection in human DRG xenografts for a 61-day interval. At 12 days after inoculation, 4.2% of neurons expressed HSV-1 proteins; frequencies increased to 32.1% at 33 days but declined to 20.8% by 61 days. Frequencies of LAT-positive neurons were 1.2% at 12 days and increased to 40.2% at 33 days. LAT expression remained at 37% at 61 days, in contrast to the decline in neurons expressing viral proteins. These observations show that the progression of HSV-1 infection is highly restricted in human DRG, and HSV-1 genome silencing occurs in human neurons infected in vivo as a consequence of virus-host cell interactions and does not require adaptive immune control. PMID:23269807

  5. On the use of administrative databases to support planning activities: the case of the evaluation of neonatal case-mix in the Emilia-Romagna region using DRG and APR-DRG classification systems. (United States)

    Fantini, M P; Cisbani, L; Manzoli, L; Vertrees, J; Lorenzoni, L


    There are several versions of the Diagnosis Related Group (DRG) classification systems that are used for case-mix analysis, utilization review, prospective payment, and planning applications. The objective of this study was to assess the adequacy of two of these DRG systems--Medicare DRG and All Patient Refined DRG--to classify neonatal patients. The first part of the paper contains a descriptive analysis that outlines the major differences between the two systems in terms of classification logic and variables used in the assignment process. The second part examines the statistical performance of each system on the basis of the administrative data collected in all public hospitals of the Emilia-Romagna region relating to neonates discharged in 1997 and 1998. The Medicare DRG are less developed in terms of classification structure and yield a poorer statistical performance in terms of reduction in variance for length of stay. This is important because, for specific areas, a more refined system can prove useful at regional level to remove systematic biases in the measurement of case-mix due to the structural characteristics of the Medicare DRGs classification system.

  6. Modulating nitric oxide levels in dorsal root ganglion neurons of rat with low-level laser therapy (United States)

    Zheng, Li-qin; Wang, Yu-hua; He, Yi-peng; Zhou, Jie; Yang, Hong-qin; Zhang, Yan-ding; Xie, Shu-sen


    Nitric oxide (NO) and nitric oxide synthase (NOS) have an important role in pain signaling transmission in animal models. Low-level laser therapy (LLLT) is known to have an analgesic effect, but the mechanism is unclear. The aim of the study is to investigate the influence of LLLT on NO release and NOS synthesis in dorsal root ganglion (DRG) neurons, in order to find whether LLLI can ameliorate pain through modulating NO production at the cellular level. The results show that in stress conditions, the laser irradiation at 658 nm can modulate NO production in DRG neurons with soma diameter of about 20 μm in a short time after illumination, and affect NOS synthesis in a dose-dependent manner. It is demonstrated that LLLT might treat pain by altering NO release directly and indirectly in DRG neurons.

  7. Ellagic acid promotes A{beta}42 fibrillization and inhibits A{beta}42-induced neurotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Ying [Department of Histology and Embryology, College of Basic Medical Science, China Medical University, Shenyang 110001 (China); Tsinghua University School of Medicine, Haidian District, Beijing 100084 (China); Yang, Shi-gao; Du, Xue-ting; Zhang, Xi; Sun, Xiao-xia; Zhao, Min [Tsinghua University School of Medicine, Haidian District, Beijing 100084 (China); Sun, Gui-yuan, E-mail: [Department of Histology and Embryology, College of Basic Medical Science, China Medical University, Shenyang 110001 (China); Liu, Rui-tian, E-mail: [Tsinghua University School of Medicine, Haidian District, Beijing 100084 (China)


    Smaller, soluble oligomers of {beta}-amyloid (A{beta}) play a critical role in the pathogenesis of Alzheimer's disease (AD). Selective inhibition of A{beta} oligomer formation provides an optimum target for AD therapy. Some polyphenols have potent anti-amyloidogenic activities and protect against A{beta} neurotoxicity. Here, we tested the effects of ellagic acid (EA), a polyphenolic compound, on A{beta}42 aggregation and neurotoxicity in vitro. EA promoted A{beta} fibril formation and significant oligomer loss, contrary to previous results that polyphenols inhibited A{beta} aggregation. The results of transmission electron microscopy (TEM) and Western blot displayed more fibrils in A{beta}42 samples co-incubated with EA in earlier phases of aggregation. Consistent with the hypothesis that plaque formation may represent a protective mechanism in which the body sequesters toxic A{beta} aggregates to render them harmless, our MTT results showed that EA could significantly reduce A{beta}42-induced neurotoxicity toward SH-SY5Y cells. Taken together, our results suggest that EA, an active ingredient in many fruits and nuts, may have therapeutic potential in AD.

  8. Allocating Inpatient Expenses to Each DRG in All Clinical Services at Darnall Army Community Hospital (United States)


    BC/BS implements drg system. Health Care Advocate Diomede, B., (1985). DRGs and surgical procedures. Association of Operatinq Room Nurses Journal...PROCEDURES WITH CC 4.4412 15.5 1 48 192 PANCREAS, LIVER & SHUNT PROCEDURES W/O CC 1.7379 8.5 1 41 193 BILIARY TRACT PROC W CC EXCEPT ONLY CHOLECYST W OR W/G...C.D.E. 3.0275 14.0 1 46 194 BILIARY TRACT PROC W/O CC EXCEPT ONLY CHOLECYST W OR W/O C.D.E. 1.6189 8.8 1 41 195 CHOLECYSTECTOMY WITH C.D.E. WITH CC

  9. PKCε-dependent potentiation of TTX-resistant Nav1.8 current by neurokinin-1 receptor activation in rat dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Zhao Zhi-Qi


    Full Text Available Abstract Background Substance P (SP, which mainly exists in a subtype of small-diameter dorsal root ganglion (DRG neurons, is an important signal molecule in pain processing in the spinal cord. Our previous results have proved the expression of SP receptor neurokinin-1 (NK-1 on DRG neurons and its interaction with transient receptor potential vanilloid 1 (TRPV1 receptor. Results In this study we investigated the effect of NK-1 receptor agonist on Nav1.8, a tetrodotoxin (TTX-resistant sodium channel, in rat small-diameter DRG neurons employing whole-cell patch clamp recordings. NK-1 agonist [Sar9, Met(O211]-substance P (Sar-SP significantly enhanced the Nav1.8 currents in a subgroup of small-diameter DRG neurons under both the normal and inflammatory situation, and the enhancement was blocked by NK-1 antagonist Win51708 and protein kinase C (PKC inhibitor bisindolylmaleimide (BIM, but not the protein kinase A (PKA inhibitor H89. In particular, the inhibitor of PKCε, a PKC isoform, completely blocked this effect. Under current clamp model, Sar-SP reduced the amount of current required to evoke action potentials and increased the firing rate in a subgroup of DRG neurons. Conclusion These data suggest that activation of NK-1 receptor potentiates Nav1.8 sodium current via PKCε-dependent signaling pathway, probably participating in the generation of inflammatory hyperalgesia.

  10. Functional upregulation of nav1.8 sodium channels on the membrane of dorsal root Ganglia neurons contributes to the development of cancer-induced bone pain.

    Directory of Open Access Journals (Sweden)

    Xiao-Dan Liu

    Full Text Available We have previously reported that enhanced excitability of dorsal root ganglia (DRG neurons contributes to the development of bone cancer pain, which severely decreases the quality of life of cancer patients. Nav1.8, a tetrodotoxin-resistant (TTX-R sodium channel, contributes most of the sodium current underlying the action potential upstroke and accounts for most of the current in later spikes in a train. We speculate that the Nav1.8 sodium channel is a potential candidate responsible for the enhanced excitability of DRG neurons in rats with bone cancer pain. Here, using electrophysiology, Western blot and behavior assays, we documented that the current density of TTX-R sodium channels, especially the Nav1.8 channel, increased significantly in DRG neurons of rats with cancer-induced bone pain. This increase may be due to an increased expression of Nav1.8 on the membrane of DRG neurons. Accordantly, blockade of Nav1.8 sodium channels by its selective blocker A-803467 significantly alleviated the cancer-induced mechanical allodynia and thermal hyperalgesia in rats. Taken together, these results suggest that functional upregulation of Nav1.8 channels on the membrane of DRG neurons contributes to the development of cancer-induced bone pain.

  11. Inhibition of cystathionine β-synthetase suppresses sodium channel activities of dorsal root ganglion neurons of rats with lumbar disc herniation (United States)

    Yan, Jun; Hu, Shufen; Zou, Kang; Xu, Min; Wang, Qianliang; Miao, Xiuhua; Yu, Shan Ping; Xu, Guang-Yin


    The pathogenesis of pain in lumbar disc herniation (LDH) remains poorly understood. We have recently demonstrated that voltage-gated sodium channels (VGSCs) in dorsal root ganglion (DRG) neurons were sensitized in a rat model of LDH. However, the detailed molecular mechanism for sensitization of VGSCs remains largely unknown. This study was designed to examine roles of the endogenous hydrogen sulfide synthesizing enzyme cystathionine β-synthetase (CBS) in sensitization of VGSCs in a previously validated rat model of LDH. Here we showed that inhibition of CBS activity by O-(Carboxymethyl) hydroxylamine hemihydrochloride (AOAA) significantly attenuated pain hypersensitivity in LDH rats. Administration of AOAA also reduced neuronal hyperexcitability, suppressed the sodium current density, and right-shifted the V1/2 of the inactivation curve, of hindpaw innervating DRG neurons, which is retrogradely labeled by DiI. In vitro incubation of AOAA did not alter the excitability of acutely isolated DRG neurons. Furthermore, CBS was colocalized with NaV1.7 and NaV1.8 in hindpaw-innervating DRG neurons. Treatment of AOAA markedly suppressed expression of NaV1.7 and NaV1.8 in DRGs of LDH rats. These data suggest that targeting the CBS-H2S signaling at the DRG level might represent a novel therapeutic strategy for chronic pain relief in patients with LDH. PMID:27905525

  12. Cost unit accounting based on a clinical pathway: a practical tool for DRG implementation. (United States)

    Feyrer, R; Rösch, J; Weyand, M; Kunzmann, U


    Setting up a reliable cost unit accounting system in a hospital is a fundamental necessity for economic survival, given the current general conditions in the healthcare system. Definition of a suitable cost unit is a crucial factor for success. We present here the development and use of a clinical pathway as a cost unit as an alternative to the DRG. Elective coronary artery bypass grafting was selected as an example. Development of the clinical pathway was conducted according to a modular concept that mirrored all the treatment processes across various levels and modules. Using service records and analyses the process algorithms of the clinical pathway were developed and visualized with CorelTM iGrafix Process 2003. A detailed process cost record constituted the basis of the pathway costing, in which financial evaluation of the treatment processes was performed. The result of this study was a structured clinical pathway for coronary artery bypass grafting together with a cost calculation in the form of cost unit accounting. The use of a clinical pathway as a cost unit offers considerable advantages compared to the DRG or clinical case. The variance in the diagnoses and procedures within a pathway is minimal, so the consumption of resources is homogeneous. This leads to a considerable improvement in the value of cost unit accounting as a strategic control instrument in hospitals.

  13. Economies of scale, physician volume for urology patients, and DRG prospective hospital payment system. (United States)

    Munoz, E; Boiardo, R; Mulloy, K; Goldstein, J; Brewster, J G; Wise, L


    Diagnosis Related Group (DRG) hospital payment has begun to squeeze hospitals financially and is likely to do so in the future. This study analyzed the relationship between the volume of urologic procedures by an individual urologist, hospital costs per patient, and outcome. We used a three-year DRG database of urology patients (N = 2,980) at an academic medical center to analyze these. Low-volume urologists (arbitrarily defined by us) had higher hospital costs per patient, financial losses versus profits under DRGs, and a poorer outcome when compared with high-volume urologists. Pearson correlation showed a positive relationship between cost per patient and physician volume for nonemergency patients (-0.129, p less than 0.0001) and emergency patients (-0.368, p less than 0.0001). This may have been explained (in part) by a greater severity of illness for patients of low-volume urologists. These findings suggest, however, that the volume of urologic procedures per urologist may be related to hospital resource consumption. The health care financing environment of the future should provide substantial interest in this finding for those involved in the consumption of urologic services.

  14. Magnitude of GAP-43 induction following peripheral axotomy of adult rat dorsal root ganglion neurons is independent of lesion distance. (United States)

    Liabotis, S; Schreyer, D J


    Regenerative axon growth in peripheral neurons is accompanied by increased expression of the growth-associated protein GAP-43. We examined the increase of GAP-43 immunoreactivity in DRG neurons following lesions at different distances along the sciatic nerve, using immunocytochemistry. To control for the variable involvement of DRG axons following injury at different sites, injured neurons were identified by retrograde labeling with Fluoro-Gold. GAP-43 labeling was similar for proximal, distal, and far-distal injuries when only injured neurons are considered. Our results stand in contrast to studies which show that GAP-43 upregulation in neurons of the central nervous system occurs only when lesions are made close to the cell body. This suggests that the mechanisms which control GAP-43 expression following injury differ between central and peripheral neurons.

  15. Hospital Staff Perceptions of Institutional Readiness for Implementation of Innovations in the Health Sector, Specifically Diagnostic Related Groups (DRG)


    Gorbanev, Iouri; Pontificia Universidad Javeriana; Cortés, Ariel; Pontificia Universidad Javeriana; Agudelo, Sandra; Pontificia Universidad Javeriana; Torres, Sergio; Pontificia Universidad Javeriana; Yepes, Francisco J.; Pontificia Universidad Javeriana


    Objectives: To characterize the state of the innovative culture and attitude of hospital staff towards Diagnosis Related Groups (DRG) like an innovation for the Colombian health care.Methods: A case study through convenience sampling among clinical and administrative staff who determine the success of the DRG. Statistical analysis was performed using descriptive statistics, regression and correspondence analysis.Results: The state of innovative culture in the Hospital is favorable for the inn...

  16. Cost accounting to determine prices: how well do prices reflect costs in the German DRG-system? (United States)

    Schreyögg, Jonas; Tiemann, Oliver; Busse, Reinhard


    Germany has recently introduced a system of Diagnosis Related Groups (DRGs) to engender more appropriate resource allocation. The following article describes the German DRG-system and the methodologies used to determine prices. It analyses the extent to which prices, or calculated cost weights, reflect the actual costs incurred by hospitals for their respective services. We reveal that a "compression" of DRG cost weights occurs, and that the data sample used to calculate cost weights is lacking in terms of its representativeness. Although cost data accuracy has improved over the last few years there are still a number of challenges that need to be addressed.

  17. Functional expression of P2X7 receptors in non-neuronal cells of rat dorsal root ganglia. (United States)

    Zhang, Xu-Feng; Han, Ping; Faltynek, Connie R; Jarvis, Michael F; Shieh, Char-Chang


    The P2X7 receptor is an ATP-sensitive ligand-gated cation channel, expressed predominantly in cells with immune origin. Recent studies have demonstrated that P2X7 may play an important role in pain signaling. In the present study, the expression of P2X7 receptors in non-neuronal cells and neurons isolated from dorsal root ganglia was characterized using patch clamp, pharmacological and confocal microscopy approaches. In small diameter DRG neurons, 100 microM 2', 3'-O-(4-benzoylbenzoyl)-ATP (BzATP) evoked an inward current, which was inhibited completely by 1 microM A-317491, a potent and selective P2X3 receptor antagonist. In contrast, BzATP evoked concentration-dependent increases in inward currents in non-neuronal DRG cells with an EC50 value of 26 +/- 0.14 microM, which were resistant to the blockade by A-317491. The activity to evoke cationic currents by P2X receptor agonists in non-neuronal cells showed a rank order of BzATP > ATP > alpha,beta-meATP. Pyridoxal-phosphate-6-azophenyl-,2',4'-disulphonic acid (PPADS) and Mg2+ produced concentration-dependent inhibition of BzATP-evoked currents in non-neuronal cells. Confocal microscopy revealed positive immunoreactivity of anti-P2X7 receptor antibodies on non-neuronal cells. No anti-P2X7 immunoreactivity was observed on DRG neurons. Further electrophysiological studies showed that prolonged agonist activation of P2X7 receptors in non-neuronal cells did not lead to cytolytic pore formation. Taken together, the present study demonstrated functional expression of P2X7 receptors in non-neuronal but not in small diameter neurons from rat DRG. Modulation of P2X7 receptors in non-neuronal cells might have impact on peripheral sensory transduction under normal and pathological states.

  18. Development of nNOS-positive neurons in the rat sensory ganglia after capsaicin treatment. (United States)

    Masliukov, Petr M; Moiseev, Konstantin Y; Korzina, Marina B; Porseva, Valentina V


    To gain a better understanding of the neuroplasticity of afferent neurons during postnatal ontogenesis, the distribution of neuronal nitric oxide synthase (nNOS) immunoreactivity was studied in the nodose ganglion (NG) and Th2 and L4 dorsal root ganglia (DRG) from vehicle-treated and capsaicin-treated female Wistar rats at different ages (10-day-old, 20-day-old, 30-day-old, and two-month-old). The percentage of nNOS-immunoreactive (IR) neurons decreased after capsaicin treatment in all studied ganglia in first 20 days of life, from 55.4% to 36.9% in the Th2 DRG, from 54.6% to 26.1% in the L4 DRG and from 37.1% to 15.0% in the NG. However, in the NG, the proportion of nNOS-IR neurons increased after day 20, from 11.8% to 23.9%. In the sensory ganglia of all studied rats, a high proportion of nNOS-IR neurons bound isolectin B4. Approximately 90% of the sensory nNOS-IR neurons bound to IB4 in the DRG and approximately 80% in the NG in capsaicin-treated and vehicle-treated rats. In 10-day-old rats, a large number of nNOS-IR neurons also expressed TrkA, and the proportion of nNOS(+)/TrkA(+) neurons was larger in the capsaicin-treated rats compared with the vehicle-treated animals. During development, the percentage of nNOS(+)/TrkA(+) cells decreased in the first month of life in both groups. The information provided here will also serve as a basis for future studies investigating mechanisms of sensory neuron development.

  19. Dorsal root ganglia neurons and differentiated adipose-derived stem cells: an in vitro co-culture model to study peripheral nerve regeneration. (United States)

    de Luca, Alba C; Faroni, Alessandro; Reid, Adam J


    Dorsal root ganglia (DRG) neurons, located in the intervertebral foramina of the spinal column, can be used to create an in vitro system facilitating the study of nerve regeneration and myelination. The glial cells of the peripheral nervous system, Schwann cells (SC), are key facilitators of these processes; it is therefore crucial that the interactions of these cellular components are studied together. Direct contact between DRG neurons and glial cells provides additional stimuli sensed by specific membrane receptors, further improving the neuronal response. SC release growth factors and proteins in the culture medium, which enhance neuron survival and stimulate neurite sprouting and extension. However, SC require long proliferation time to be used for tissue engineering applications and the sacrifice of an healthy nerve for their sourcing. Adipose-derived stem cells (ASC) differentiated into SC phenotype are a valid alternative to SC for the set-up of a co-culture model with DRG neurons to study nerve regeneration. The present work presents a detailed and reproducible step-by-step protocol to harvest both DRG neurons and ASC from adult rats; to differentiate ASC towards a SC phenotype; and combines the two cell types in a direct co-culture system to investigate the interplay between neurons and SC in the peripheral nervous system. This tool has great potential in the optimization of tissue-engineered constructs for peripheral nerve repair.

  20. Into the groove: instructive silk-polypyrrole films with topographical guidance cues direct DRG neurite outgrowth. (United States)

    Hardy, John G; Khaing, Zin Z; Xin, Shangjing; Tien, Lee W; Ghezzi, Chiara E; Mouser, David J; Sukhavasi, Rushi C; Preda, Rucsanda C; Gil, Eun S; Kaplan, David L; Schmidt, Christine E


    Instructive biomaterials capable of controlling the behaviour of the cells are particularly interesting scaffolds for tissue engineering and regenerative medicine. Novel biomaterials are particularly important in societies with rapidly aging populations, where demand for organ/tissue donations is greater than their supply. Herein we describe the preparation of electrically conductive silk film-based nerve tissue scaffolds that are manufactured using all aqueous processing. Aqueous solutions of Bombyx mori silk were cast on flexible polydimethylsiloxane substrates with micrometer-scale grooves on their surfaces, allowed to dry, and annealed to impart β-sheets to the silk which assures that the materials are stable for further processing in water. The silk films were rendered conductive by generating an interpenetrating network of polypyrrole and polystyrenesulfonate in the silk matrix. Films were incubated in an aqueous solution of pyrrole (monomer), polystyrenesulfonate (dopant) and iron chloride (initiator), after which they were thoroughly washed to remove low molecular weight components (monomers, initiators, and oligomers) and dried, yielding conductive films with sheet resistances of 124 ± 23 kΩ square(-1). The micrometer-scale grooves that are present on the surface of the films are analogous to the natural topography in the extracellular matrix of various tissues (bone, muscle, nerve, skin) to which cells respond. Dorsal root ganglions (DRG) adhere to the films and the grooves in the surface of the films instruct the aligned growth of processes extending from the DRG. Such materials potentially enable the electrical stimulation (ES) of cells cultured on them, and future in vitro studies will focus on understanding the interplay between electrical and topographical cues on the behaviour of cells cultured on them.

  1. Enhanced adenoviral gene delivery to motor and dorsal root ganglion neurons following injection into demyelinated peripheral nerves. (United States)

    Zhang, Yongjie; Zheng, Yiyan; Zhang, Yi Ping; Shields, Lisa B E; Hu, Xiaoling; Yu, Panpan; Burke, Darlene A; Wang, Heming; Jun, Cai; Byers, Jonathan; Whittemore, Scott R; Shields, Christopher B


    Injection of viral vectors into peripheral nerves may transfer specific genes into their dorsal root ganglion (DRG) neurons and motoneurons. However, myelin sheaths of peripheral axons block the entry of viral particles into nerves. We studied whether mild, transient peripheral nerve demyelination prior to intraneural viral vector injection would enhance gene transfer to target DRG neurons and motoneurons. The right sciatic nerve of C57BL/6 mice was focally demyelinated with 1% lysolecithin, and the left sciatic nerve was similarly injected with saline (control). Five days after demyelination, 0.5 microl of Ad5-GFP was injected into both sciatic nerves at the site of previous injection. The effectiveness of gene transfer was evaluated by counting GFP(+) neurons in the DRGs and ventral horns. After peripheral nerve demyelination, there was a fivefold increase in the number of infected DRG neurons and almost a 15-fold increase in the number of infected motoneurons compared with the control, nondemyelinated side. Focal demyelination reduced the myelin sheath barrier, allowing greater virus-axon contact. Increased CXADR expression on the demyelinated axons facilitated axoplasmic viral entry. No animals sustained any prolonged neurological deficits. Increased gene delivery into DRG neurons and motoneurons may provide effective treatment for amyotrophic lateral sclerosis, pain, and spinal cord injury.

  2. Neuronal nitric oxide synthase mRNA upregulation in rat sensory neurons after spinal nerve ligation: lack of a role in allodynia development. (United States)

    Luo, Z D; Chaplan, S R; Scott, B P; Cizkova, D; Calcutt, N A; Yaksh, T L


    Pharmacological evidence suggests a functional role for spinal nitric oxide (NO) in the modulation of thermal and/or inflammatory hyperalgesia. To assess the role of NO in nerve injury-induced tactile allodynia, we examined neuronal NO synthase (nNOS) expression in the spinal cord and dorsal root ganglia (DRG) of rats with tactile allodynia because of either tight ligation of the left fifth and sixth lumbar spinal nerves or streptozotocin-induced diabetic neuropathy. RNase protection assays indicated that nNOS mRNA (1) was upregulated in DRG, but not spinal cord, neurons on the injury side beginning 1 d after nerve ligation, (2) peaked (approximately 10-fold increase) at 2 d, and (3) remained elevated for at least 13 weeks. A corresponding increase in DRG nNOS protein was also observed and localized principally to small and occasionally medium-size sensory neurons. In rats with diabetic neuropathy, there was no significant change in DRG nNOS mRNA. However, similar increases in DRG nNOS mRNA were observed in rats that did not develop allodynia after nerve ligation and in rats fully recovered from allodynia 3 months after the nerve ligation. Systemic treatment with a specific pharmacological inhibitor of nNOS failed to prevent or reverse allodynia in nerve-injured rats. Thus, regulation of nNOS may contribute to the development of neuronal plasticity after specific types of peripheral nerve injury. However, upregulation of nNOS is not responsible for the development and/or maintenance of allodynia after nerve injury.

  3. The sensitivity of neurons with non-periodic activity to sympathetic stimulation in rat injured dorsal root ganglion

    Institute of Scientific and Technical Information of China (English)

    Hong-Jun YANG; San-Jue HU; Pu-Lin GONG; Jian-Hong DUAN


    Objective The relationship between firing pattern and sensitivity of neurons was studied in chronically compressed dorsal root ganglion (DRG) neurons and the Hindmarsh-Rose (HR) neuronal model. Methods Spontaneous activities from single fibers of chronically compressed DRG neurons in rats were recorded, and divided into periodic and non-periodic firing patterns. The sensitivity of the two kinds of firing pattern neuron to sympathetic stimulation (SS)was compared. Result It was found that 27.3% of periodic firing neurons and 93.2% of non-periodic firing neurons responded to SS respectively ( periodic vs non-periodic, P < 0.01 ). The responses to SS with different stimulation time were greater non-periodic firing neurons than periodic firing neurons (P < 0.01 ). The non-periodic firing neurons obviously responded to SS. After the firing pattern of these neurons transformed to periodic firing pattern, their responses to SS disappeared or decreased obviously. The HR neuronal model exhibited a significantly greater response to perturbation in non-periodic (chaotic) firing pattern than in periodic firing pattern. Conclusion The non-periodic firing neurons with deterministic chaos are more sensitive to external stimuli than the periodic firing neurons.

  4. Effects of the DRG-based prospective payment system operated by the voluntarily participating providers on the cesarean section rates in Korea. (United States)

    Lee, Kwangsoo; Lee, Sangil


    This study explored the effects of the diagnosis-related group (DRG)-based prospective payment system (PPS) operated by voluntarily participating organizations on the cesarean section (CS) rates, and analyzed whether the participating health care organizations had similar CS rates despite the varied participation periods. The study sample included delivery claims data from the Korean national health insurance program for the year 2003. Risk factors were identified and used in the adjustment model to distinguish the main reason for CS. Their risk-adjusted CS rates were compared by the reimbursement methods, and the organizations' internal and external environments were controlled. The final risk-adjustment model for the CS rates meets the criteria for an effective model. There were no significant differences of CS rates between providers in the DRG and fee-for-service system after controlling for organizational variables. The CS rates did not vary significantly depending on the providers' DRG participation periods. The results provide evidence that the DRG payment system operated by volunteering health care organizations had no impact on the CS rates, which can lower the quality of care. Although the providers joined the DRG system in different years, there were no differences in the CS rates among the DRG providers. These results support the future expansion of the DRG-based PPS plan to all health care services in Korea.

  5. Inflammation in the uterus induces phosphorylated extracellular signal-regulated kinase and substance P immunoreactivity in dorsal root ganglia neurons innervating both uterus and colon in rats. (United States)

    Li, Jichang; Micevych, Paul; McDonald, John; Rapkin, Andrea; Chaban, Victor


    In women, clinical studies suggest that pain syndromes such as irritable bowel syndrome and interstitial cystitis, which are associated with visceral hyperalgesia, are often comorbid with endometriosis and chronic pelvic pain. One of the possible explanations for this phenomenon is viscerovisceral cross-sensitization, in which increased nociceptive input from an inflamed pelvic organ sensitizes neurons that receive convergent input to the same dorsal root ganglion (DRG) from an unaffected visceral organ. Nociception induces up-regulation of cellular mechanisms such as phosphorylated extracellular signal-regulated kinase (pERK) and substance P (SP), neurotransmitters associated with induced pain sensation. The purpose of this study was to determine, in a rodent model, whether uterine inflammation increased the number of pERK- and SP-positive neurons that received input from both the uterus and the colon. Cell bodies of colonic and uterine DRG were retrogradely labeled with fluorescent tracer dyes microinjected into the colon/rectum and into the uterus. Ganglia were harvested for fluorescent microscopy to identify positively stained neurons. Approximately 6% of neurons were colon specific and 10% uterus specific. Among these uterus- or colon-specific neurons, up to 3-5% of DRG neurons in the lumbosacral neurons (L1-S3 levels) received input from both visceral organs. Uterine inflammation increased the number of pERK- and SP-immunoreactive DRG neurons innervating specifically colon, or innervating specifically uterus, and those innervating both organs. These results suggest that a localized inflammation activates primary visceral afferents, regardless of whether they innervate the affected organ. This visceral sensory integration in the DRG may underlie the observed comorbidity of female pelvic pain syndromes.

  6. Regulation, retrenchment--the DRG experience: problems from changing reimbursement practice. (United States)

    Gay, E G; Kronenfeld, J J


    A study of 227,771 discharge abstracts from one U.S. state's short-term, acute care hospitals compares changes in the inpatient market available to the oldest old Medicare patients (85 and older) with those less than 70 and those 70-84 between 1981, the last year when all hospitals were under cost-based reimbursement, and 1984, the first year in which all hospitals were under a prospective payment system based on diagnosis related groups (DRGs). All three populations experienced retrenchment in services as hospitals pursued practice changes to enhance revenue potential. An older, sicker client was admitted as hospitals implemented changes in admission patterns to avoid denial of reimbursement for an admission deemed inappropriate by the Peer Review Organization (PRO). Evidence demonstrates compression in service markets and retrenchment in services for less profitable DRGs and/or cohorts. Inpatient services were reduced the most for the oldest old population although this cohort was the sickest. Changes were observed in utilization of special care units, such as in coronary and intensive care units. Large increases in readmissions in all three cohorts suggests that DRG incentives to reduce length of hospital stay may have promoted premature discharge. Or, perhaps these readmissions resulted from 'unbundling', a practice of splitting patient problems into multiple admissions, as hospitals sought ways to enhance revenue instead of practicing cost-containment. Policy, perceived to be economically stringent, can affect hospital practice and produce undesired results with long-reaching untoward effects on certain segments of the population.

  7. Cajal body number and nucleolar size correlate with the cell body mass in human sensory ganglia neurons. (United States)

    Berciano, Maria T; Novell, Mariona; Villagra, Nuria T; Casafont, Iñigo; Bengoechea, Rocio; Val-Bernal, J Fernado; Lafarga, Miguel


    This paper studies the cell size-dependent organization of the nucleolus and Cajal bodies (CBs) in dissociated human dorsal root ganglia (DRG) neurons from autopsy tissue samples of patients without neurological disease. The quantitative analysis of nucleoli with an anti-fibrillarin antibody showed that all neurons have only one nucleolus. However, the nucleolar volume and the number of fibrillar centers per nucleolus significantly increase as a function of cell body size. Immunostaining for coilin demonstrated the presence of numerous CBs in DRG neurons (up to 20 in large size neurons). The number of CBs per neuron correlated positively with the cell body volume. Light and electron microscopy immunocytochemical analysis revealed the concentration of coilin, snRNPs, SMN and fibrillarin in CBs of DRG neurons. CBs were frequently associated with the nucleolus, active chromatin domains and PML bodies, but not with telomeres. Our results support the view that the nucleolar volume and number of both fibrillar centers and CBs depend on the cell body mass, a parameter closely related to transcriptional and synaptic activity in mammalian neurons. Moreover, the unusual large number of CBs could facilitate the transfer of RNA processing components from CBs to nucleolar and nucleoplasmic sites of RNA processing.

  8. Distinct functional and temporal requirements for zebrafish Hdac1 during neural crest-derived craniofacial and peripheral neuron development.

    Directory of Open Access Journals (Sweden)

    Myron S Ignatius

    Full Text Available The regulation of gene expression is accomplished by both genetic and epigenetic means and is required for the precise control of the development of the neural crest. In hdac1(b382 mutants, craniofacial cartilage development is defective in two distinct ways. First, fewer hoxb3a, dlx2 and dlx3-expressing posterior branchial arch precursors are specified and many of those that are consequently undergo apoptosis. Second, in contrast, normal numbers of progenitors are present in the anterior mandibular and hyoid arches, but chondrocyte precursors fail to terminally differentiate. In the peripheral nervous system, there is a disruption of enteric, DRG and sympathetic neuron differentiation in hdac1(b382 mutants compared to wildtype embryos. Specifically, enteric and DRG-precursors differentiate into neurons in the anterior gut and trunk respectively, while enteric and DRG neurons are rarely present in the posterior gut and tail. Sympathetic neuron precursors are specified in hdac1(b382 mutants and they undergo generic neuronal differentiation but fail to undergo noradrenergic differentiation. Using the HDAC inhibitor TSA, we isolated enzyme activity and temporal requirements for HDAC function that reproduce hdac1(b382 defects in craniofacial and sympathetic neuron development. Our study reveals distinct functional and temporal requirements for zebrafish hdac1 during neural crest-derived craniofacial and peripheral neuron development.

  9. Immortalized human dorsal root ganglion cells differentiate into neurons with nociceptive properties. (United States)

    Raymon, H K; Thode, S; Zhou, J; Friedman, G C; Pardinas, J R; Barrere, C; Johnson, R M; Sah, D W


    A renewable source of human sensory neurons would greatly facilitate basic research and drug development. We had established previously conditionally immortalized human CNS cell lines that can differentiate into functional neurons (). We report here the development of an immortalized human dorsal root ganglion (DRG) clonal cell line, HD10.6, with a tetracycline-regulatable v-myc oncogene. In the proliferative condition, HD10.6 cells have a doubling time of 1.2 d and exhibit a neuronal precursor morphology. After differentiation of clone HD10.6 for 7 d in the presence of tetracycline, v-myc expression was suppressed, and >50% of the cells exhibited typical neuronal morphology, stained positively for neuronal cytoskeletal markers, and fired action potentials in response to current injection. Furthermore, this cell line was fate-restricted to a neuronal phenotype; even in culture conditions that promote Schwann cell or smooth muscle differentiation of neural crest stem cells, HD10.6 differentiated exclusively into neurons. Moreover, differentiated HD10.6 cells expressed sensory neuron-associated transcription factors and exhibited capsaicin sensitivity. Taken together, these data indicate that we have established an immortalized human DRG cell line that can differentiate into sensory neurons with nociceptive properties. The cell line HD10.6 represents the first example of a human sensory neuronal line and will be valuable for basic research, as well as for the discovery of novel drug targets and clinical candidates.

  10. Visceral sensory neurons that innervate both uterus and colon express nociceptive TRPv1 and P2X3 receptors in rats. (United States)

    Chaban, Victor V


    In women, clinical studies suggest that functional pain syndromes such as irritable bowel syndrome, interstitial cystitis, and fibromyalgia, are co-morbid with endometriosis, chronic pelvic pain, and others diseases. One of the possible explanations for this phenomenon is visceral cross-sensitization in which increased nociceptive input from inflamed reproductive system organs sensitize neurons that receive convergent input from an unaffected visceral organ to the same dorsal root ganglion (DRG). The purpose of this study was to determine whether primary sensory neurons that innervate both visceral organs--the uterus and the colon--express nociceptive ATP-sensitive purinergic (P2X3) and capsaicin-sensitive vanilloid (TRPV1) receptors. To test this hypothesis, cell bodies of colonic and uterine DRG were retrogradely labeled with fluorescent tracer dyes micro-injected into the colon/rectum and uterus of rats. Ganglia were harvested, cryo-protected, and cut in 20-microm slices for fluorescent microscopy to identify positively stained cells. Up to 5% neurons were colon-specific or uterus-specific, and 10%-15% of labeled DRG neurons innervate both viscera in the lumbosacral neurons (L1-S3 levels). We found that viscerally labeled DRGs express nociceptive P2X3 and TRPV1 receptors. Our results suggest a novel form of visceral sensory integration in the DRG that may underlie co-morbidity of many functional pain syndromes.

  11. Topographic Digital Raster Graphics, DRG - 1:250,000 Topo - Quads (7.5 Minute), Published in 1996, Arizona State Land Department. (United States)

    NSGIC GIS Inventory (aka Ramona) — This Topographic Digital Raster Graphics dataset, was produced all or in part from Hardcopy Maps information as of 1996. It is described as 'DRG - 1:250,000 Topo -...

  12. Small-fiber neuropathy Nav1.8 mutation shifts activation to hyperpolarized potentials and increases excitability of dorsal root ganglion neurons. (United States)

    Huang, Jianying; Yang, Yang; Zhao, Peng; Gerrits, Monique M; Hoeijmakers, Janneke G J; Bekelaar, Kim; Merkies, Ingemar S J; Faber, Catharina G; Dib-Hajj, Sulayman D; Waxman, Stephen G


    Idiopathic small-fiber neuropathy (I-SFN), clinically characterized by burning pain in distal extremities and autonomic dysfunction, is a disorder of small-caliber nerve fibers of unknown etiology with limited treatment options. Functional variants of voltage-gated sodium channel Nav1.7, encoded by SCN9A, have been identified in approximately one-third of I-SFN patients. These variants render dorsal root ganglion (DRG) neurons hyperexcitable. Sodium channel Nav1.8, encoded by SCN10A, is preferentially expressed in small-diameter DRG neurons, and produces most of the current underlying the upstroke of action potentials in these neurons. We previously demonstrated two functional variants of Nav1.8 that either enhance ramp current or shift activation in a hyperpolarizing direction, and render DRG neurons hyperexcitable, in I-SFN patients with no mutations of SCN9A. We have now evaluated additional I-SFN patients with no mutations in SCN9A, and report a novel I-SFN-related Nav1.8 mutation I1706V in a patient with painful I-SFN. Whole-cell voltage-clamp recordings in small DRG neurons demonstrate that the mutation hyperpolarizes activation and the response to slow ramp depolarizations. However, it decreases fractional channels resistant to fast inactivation and reduces persistent currents. Current-clamp studies reveal that mutant channels decrease current threshold and increase the firing frequency of evoked action potentials within small DRG neurons. These observations suggest that the effects of this mutation on activation and ramp current are dominant over the reduced persistent current, and show that these pro-excitatory gating changes confer hyperexcitability on peripheral sensory neurons, which may contribute to pain in this individual with I-SFN.

  13. Effects of complete Freund's adjuvant on immunohistochemical distribution of IL-1β and IL-1R I in neurons and glia cells of dorsal root ganglion

    Institute of Scientific and Technical Information of China (English)

    Man LI; Chuan-you LIN; Xin-min GUAN; Jing SHI; Jun-rui TANG; Di CHEN; Bo AI; Jun CHEN; Li-na WANG; Fu-yuan CAO; Ling-li LI


    Aim: To investigate the effects of complete Freund's adjuvant (CFA) on inflammatory hyperalgesia and morphological change of the coexsistence of interleukin- 1 beta (IL-1β) and type Ⅰ IL-1 receptor (IL-1RI) in neurons and glia cells of rat dorsal root ganglion (DRG). Methods: The pain-related parameters and the expression of IL- 1RI and IL-1β positive neurons and glia cells of DRG in normal saline (NS) and adjuvant-induced arthritic (AA) group were examined with pain behavior assessment methods and immunohistochemical assay, respectively. Results: Five hours,1 d, and 2 d after intra-articular injection of 50 μL CFA, tactile hyperalgesia in duced by CFA was observed in the foot flexion and extension scores of the ipsilateral hindpaw of AA group. Three days after injection, the distribution of IL-1RI/ IL-1β double-stained coexisted neurons and glia cells were observed in ipsilateral DRG of both groups. The number of IL-1β positive neurons, IL-1RI positive neurons, IL-1 β/IL-1RI double-stained neurons, and IL-1RI positive glia cells in ipsilateral DRG of the AA group were higher than that of NS group (P<0.05 or P< 0.01). Conclusion: The coexsistence of IL- 1 β and IL- 1 RI in neurons and nonneuronal cells suggests an as yet unknown autocrine and/or paracrine function of IL-1 β in the DRG. The function was enhanced in articular arthritis induced by CFA and could play an important role in hyperalgesia under inflammatory conditions.

  14. Voltage-gated potassium channels involved in regulation of physiological function in MrgprA3-specific itch neurons. (United States)

    Tang, Min; Wu, Guanyi; Wang, Zhongli; Yang, Niuniu; Shi, Hao; He, Qian; Zhu, Chan; Yang, Yan; Yu, Guang; Wang, Changming; Yuan, Xiaolin; Liu, Qin; Guan, Yun; Dong, Xinzhong; Tang, Zongxiang


    Itch is described as an unpleasant or irritating skin sensation that elicits the desire or reflex to scratch. MrgprA3, one of members of the Mrgprs family, is specifically expressed in a subpopulation of dorsal root ganglion (DRG) in the peripheral nervous system (PNS). These MrgprA3-expressing DRG neurons have been identified as itch-specific neurons. They can be activated by the compound, chloroquine, which is used as a drug to treat malaria. In the present study, we labeled these itch-specific neurons using the method of molecular genetic markers, and then studied their electrophysiological properties. We also recorded the cutaneous MrgprA3(-) neurons retrogradely labeled by Dil dye (MrgprA3(-)-Dil). We first found that MrgprA3(+) neurons have a lower excitability than MrgprA3(-) neurons (MrgprA3(-)-non-Dil and MrgprA3(-)-Dil). The number of action potential (AP) was reduced more obviously in MrgprA3(+) neurons than that of in MrgprA3(-) neurons. In most cases, MrgprA3(+) neurons only generated single AP; however, in MrgprA3(-) neurons, the same stimulation could induce multiple AP firing due to the greater voltage-gated potassium (Kv) current existence in MrgprA3(+) than in MrgprA3(-) neurons. Thus, Kv current plays an important role in the regulation of excitability in itch-specific neurons.

  15. Rapid method for culturing embryonic neuron-glial cell cocultures

    DEFF Research Database (Denmark)

    Svenningsen, Åsa Fex; Shan, Wei-Song; Colman, David R;


    A streamlined, simple technique for primary cell culture from E17 rat tissue is presented. In an attempt to standardize culturing methods for all neuronal cell types in the embryo, we evaluated a commercial medium without serum and used similar times for trypsinization and tested different surfaces...... for plating. In 1 day, using one method and a single medium, it is possible to produce robust E17 cultures of dorsal root ganglia (DRG), cerebellum, and enteric plexi. Allowing the endogenous glial cells to repopulate the cultures saves time compared with existing techniques, in which glial cells are added...... to cultures first treated with antimitotic agents. It also ensures that all the cells present in vivo will be present in the culture. Myelination commences after approximately 2 weeks in culture for dissociated DRG and 3-4 weeks in cerebellar cultures. In enteric cultures, glial wrapping of the enteric...

  16. History of the discovery of neuronal death in embryos. (United States)

    Hamburger, V


    The German anatomists, M. Ernst and A. Glücksmann, deserve credit for the discovery of widespread cell death in embryonic tissues, including the nervous tissue. In 1934, V. Hamburger described a significant hypoplasia in dorsal root ganglia (DGR) and lateral motor columns, following the extirpation of limb buds in chick embryos. In the early 1940s, Dr. Rita Levi-Montalcini in Turin (Italy) repeated the experiment and suggested that the hypoplasia might result from the death of young differentiated neurons. In a joint reinvestigation, published in 1949, large numbers of degenerating neurons were described in brachial DRG, following wing bud extirpations. In the same embryos, Dr. Levi-Montalcini observed massive neuronal death in cervical and thoracic DRG which had not been affected by the operation. This was the discovery of naturally occurring neuronal death. Long after the discovery of Nerve Growth Factor (NGF) it was recognized that NGF and natural neuronal death are two sides of the same coin: the latter results from an insufficient supply of the former by the target tissues.

  17. A SAGE-based screen for genes expressed in sub-populations of neurons in the mouse dorsal root ganglion

    Directory of Open Access Journals (Sweden)

    Garces Alain


    Full Text Available Abstract Background The different sensory modalities temperature, pain, touch and muscle proprioception are carried by somatosensory neurons of the dorsal root ganglia. Study of this system is hampered by the lack of molecular markers for many of these neuronal sub-types. In order to detect genes expressed in sub-populations of somatosensory neurons, gene profiling was carried out on wild-type and TrkA mutant neonatal dorsal root ganglia (DRG using SAGE (serial analysis of gene expression methodology. Thermo-nociceptors constitute up to 80 % of the neurons in the DRG. In TrkA mutant DRGs, the nociceptor sub-class of sensory neurons is lost due to absence of nerve growth factor survival signaling through its receptor TrkA. Thus, comparison of wild-type and TrkA mutants allows the identification of transcripts preferentially expressed in the nociceptor or mechano-proprioceptor subclasses, respectively. Results Our comparison revealed 240 genes differentially expressed between the two tissues (P Conclusion We have identified and characterized the detailed expression patterns of three genes in the developing DRG, placing them in the context of the known major neuronal sub-types defined by molecular markers. Further analysis of differentially expressed genes in this tissue promises to extend our knowledge of the molecular diversity of different cell types and forms the basis for understanding their particular functional specificities.

  18. Adeno-associated virus and lentivirus vectors mediate efficient and sustained transduction of cultured mouse and human dorsal root ganglia sensory neurons. (United States)

    Fleming, J; Ginn, S L; Weinberger, R P; Trahair, T N; Smythe, J A; Alexander, I E


    Peripheral nervous system (PNS) sensory neurons are directly involved in the pathophysiology of numerous inherited and acquired neurological conditions. Therefore, efficient and stable gene delivery to these postmitotic cells has significant therapeutic potential. Among contemporary vector systems capable of neuronal transduction, only those based on herpes simplex virus have been extensively evaluated in PNS neurons. We therefore investigated the transduction performance of recombinant adeno-associated virus type 2 (AAV) and VSV-G-pseudotyped lentivirus vectors derived from human immunodeficiency virus (HIV-1) in newborn mouse and fetal human dorsal root ganglia (DRG) sensory neurons. In dissociated mouse DRG cultures both vectors achieved efficient transduction of sensory neurons at low multiplicities of infection (MOIs) and sustained transgene expression within a 28-day culture period. Interestingly, the lentivirus vector selectively transduced neurons in murine cultures, in contrast to human cultures, in which Schwann and fibroblast-like cells were also transduced. Recombinant AAV transduced all three cell types in both mouse and human cultures. After direct microinjection of murine DRG explants, maximal transduction efficiencies of 20 and 200 transducing units per neuronal transductant were achieved with AAV and lentivirus vectors, respectively. Most importantly, both vectors achieved efficient and sustained transduction of human sensory neurons in dissociated cultures, thereby directly demonstrating the exciting potential of these vectors for gene therapy applications in the PNS.

  19. Stimulation of neuronal neurite outgrowth using functionalized carbon nanotubes (United States)

    Matsumoto, K.; Sato, C.; Naka, Y.; Whitby, R.; Shimizu, N.


    Low concentrations (0.11-1.7 µg ml - 1) of functionalized carbon nanotubes (CNTs), which are multi-walled CNTs modified by amino groups, when added with nerve growth factor (NGF), promoted outgrowth of neuronal neurites in dorsal root ganglion (DRG) neurons and rat pheochromocytoma cell line PC12h cells in culture media. The quantity of active extracellular signal-regulated kinase (ERK) was higher after the addition of both 0.85 µg ml - 1 CNTs and NGF than that with NGF alone. CNTs increased the number of cells with neurite outgrowth in DRG neurons and PC12h cells after the inhibition of the ERK signaling pathway using a mitogen-activated protein kinase (MAPK)/ERK kinase (MEK) inhibitor. Active ERK proteins were detected in MEK inhibitor-treated neurons after the addition of CNTs to the culture medium. These results demonstrate that CNTs may stimulate neurite outgrowth by activation of the ERK signaling pathway. Thus, CNTs are biocompatible and are promising candidates for biological applications and devices.

  20. Stimulation of neuronal neurite outgrowth using functionalized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, K; Sato, C; Shimizu, N [Graduate School of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma 374-0193 (Japan); Naka, Y [Bio-Nano Electronics Research Center, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama 350-8585 (Japan); Whitby, R, E-mail: [School of Pharmacy and Biomolecular Sciences, University of Brighton, Cockroft Building, Lewes Road, Brighton BN2 4GJ (United Kingdom)


    Low concentrations (0.11-1.7 {mu}g ml{sup -1}) of functionalized carbon nanotubes (CNTs), which are multi-walled CNTs modified by amino groups, when added with nerve growth factor (NGF), promoted outgrowth of neuronal neurites in dorsal root ganglion (DRG) neurons and rat pheochromocytoma cell line PC12h cells in culture media. The quantity of active extracellular signal-regulated kinase (ERK) was higher after the addition of both 0.85 {mu}g ml{sup -1} CNTs and NGF than that with NGF alone. CNTs increased the number of cells with neurite outgrowth in DRG neurons and PC12h cells after the inhibition of the ERK signaling pathway using a mitogen-activated protein kinase (MAPK)/ERK kinase (MEK) inhibitor. Active ERK proteins were detected in MEK inhibitor-treated neurons after the addition of CNTs to the culture medium. These results demonstrate that CNTs may stimulate neurite outgrowth by activation of the ERK signaling pathway. Thus, CNTs are biocompatible and are promising candidates for biological applications and devices.

  1. Peripherally-derived BDNF promotes regeneration of ascending sensory neurons after spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Xing-Yun Song

    Full Text Available BACKGROUND: The blood brain barrier (BBB and truncated trkB receptor on astrocytes prevent the penetration of brain derived neurotrophic factor (BDNF applied into the peripheral (PNS and central nervous system (CNS thus restrict its application in the treatment of nervous diseases. As BDNF is anterogradely transported by axons, we propose that peripherally derived and/or applied BDNF may act on the regeneration of central axons of ascending sensory neurons. METHODOLOGY/PRINCIPAL FINDINGS: The present study aimed to test the hypothesis by using conditioning lesion of the sciatic nerve as a model to increase the expression of endogenous BDNF in sensory neurons and by injecting exogenous BDNF into the peripheral nerve or tissues. Here we showed that most of regenerating sensory neurons expressed BDNF and p-CREB but not p75NTR. Conditioning-lesion induced regeneration of ascending sensory neuron and the increase in the number of p-Erk positive and GAP-43 positive neurons was blocked by the injection of the BDNF antiserum in the periphery. Enhanced neurite outgrowth of dorsal root ganglia (DRG neurons in vitro by conditioning lesion was also inhibited by the neutralization with the BDNF antiserum. The delivery of exogenous BDNF into the sciatic nerve or the footpad significantly increased the number of regenerating DRG neurons and regenerating sensory axons in the injured spinal cord. In a contusion injury model, an injection of BDNF into the footpad promoted recovery of motor functions. CONCLUSIONS/SIGNIFICANCE: Our data suggest that endogenous BDNF in DRG and spinal cord is required for the enhanced regeneration of ascending sensory neurons after conditioning lesion of sciatic nerve and peripherally applied BDNF may have therapeutic effects on the spinal cord injury.

  2. Increased gene and protein expressions of the transient receptor potential vanilloid receptor 4 following sustained pure mechanical pressure on rat dorsal root ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    Yang Zhang; Juan Huai; Yonghui Wang; Yanqin Wang; Shouwei Yue


    Dorsal root ganglion (DRG) neurons from newborn Wistar rats cultured in vitro were pressurized with 20, 40, 80 or 120 mm Hg compressive loadings (1 mm Hg = 0.133 kPa) for 12, 24, 48 or 72 hours, respectively. The 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide test showed that pressures less than 80 mm Hg had no obvious impact on the activity of DRG neurons. The protein expression levels of transient receptor potential vanilloid receptor 4 (TRPV4), transient receptor potential vanilloid receptor 1, transient receptor potential channel of melastatin type 8, and transient receptor potential subtype ankyrin 1 were assessed by western blot analysis. The mRNA expression of TRPV4 was assessed by real-time PCR. The results showed that sustained mechanical compression up-regulated TRPV4 mRNA and protein expression in the rat DRG neurons, in a time-dependent fashion. Similar changes were not found in the protein expression of transient receptor potential vanilloid receptor 1, transient receptor potential channel of melastatin type 8, and transient receptor potential subtype ankyrin 1. Images of cells using a laser scanning confocal microscope showed that the sustained mechanical pressure increased the number of responsive DRG neurons and was synergistic on the enhanced Ca2+ responses to the TRPV4 phorbol ester agonist 4a-phorbol 12, 13-didecanoate and hypotonic solutions. These findings demonstrate that sustained mechanical compressive loading in vitro increases the expression of TRPV4 mRNA and protein in DRG neurons and sensitizes TRPV4 Ca2+ signals. Mechanical compression does not impact other ion channels in thetransient receptor potential family.

  3. Reactive species modify NaV1.8 channels and affect action potentials in murine dorsal root ganglion neurons. (United States)

    Schink, Martin; Leipold, Enrico; Schirmeyer, Jana; Schönherr, Roland; Hoshi, Toshinori; Heinemann, Stefan H


    Dorsal root ganglion (DRG) neurons are important relay stations between the periphery and the central nervous system and are essential for somatosensory signaling. Reactive species are produced in a variety of physiological and pathophysiological conditions and are known to alter electric signaling. Here we studied the influence of reactive species on the electrical properties of DRG neurons from mice with the whole-cell patch-clamp method. Even mild stress induced by either low concentrations of chloramine-T (10 μM) or low-intensity blue light irradiation profoundly diminished action potential frequency but prolonged single action potentials in wild-type neurons. The impact on evoked action potentials was much smaller in neurons deficient of the tetrodotoxin (TTX)-resistant voltage-gated sodium channel NaV1.8 (NaV1.8(-/-)), the channel most important for the action potential upstroke in DRG neurons. Low concentrations of chloramine-T caused a significant reduction of NaV1.8 peak current and, at higher concentrations, progressively slowed down inactivation. Blue light had a smaller effect on amplitude but slowed down NaV1.8 channel inactivation. The observed effects were less apparent for TTX-sensitive NaV channels. NaV1.8 is an important reactive-species-sensitive component in the electrical signaling of DRG neurons, potentially giving rise to loss-of-function and gain-of-function phenomena depending on the type of reactive species and their effective concentration and time of exposure.

  4. Monitoring the impact of the DRG payment system on nursing service context factors in Swiss acute care hospitals: Study protocol. (United States)

    Spirig, Rebecca; Spichiger, Elisabeth; Martin, Jacqueline S; Frei, Irena Anna; Müller, Marianne; Kleinknecht, Michael


    Ziel: Mit diesem Studienprotokoll wird ein Forschungsprogramm eingeführt. Dessen Ziel ist das Vorbereiten der Instrumente und das Durchführen des ersten Monitorings von Pflegekontextfaktoren an drei Universitäts- und zwei Kantonsspitälern in der Schweiz noch vor Einführung der DRG-basierten Finanzierung, sowie darauf aufbauend das Weiterentwickeln des theoretischen Modells und der dazu gehörenden Methodologie für zukünftige Monitorings nach Einführung der DRGs.Hintergrund: Die DRG-basierte Finanzierung wurde 2012 in der Schweiz eingeführt. In anderen Ländern führte die Einführung der DRGs zu einer Leistungsbeschränkung und folglich auch zu einer Reduktion der Pflege. Dadurch werden das Erreichen erwünschter pflegesensitiver Patientenergebnisse und die Patientensicherheit gefährdet. Die Schweiz hat die Chance, aus den Erfahrungen anderer Länder im Zusammenhang mit der Einführung der DRG-basierten Finanzierung zu lernen. Deren Erfahrungen unterstreichen den Einfluss der DRGs auf Pflegekontextfaktoren wie die Komplexität der Pflege oder das Führungsverhalten, die ihrerseits pflegesensitive Patientenergebnisse beeinflussen. Vor diesem Hintergrund ist ein begleitendes Monitoring von Pflegekontextfaktoren als integraler Bestandteil der DRG Einführung angemessen. Aktuell werden jedoch in den meisten Schweizer Akutspitälern die Daten solcher Kontextfaktoren nicht regelmässig erhoben. Damit in Zukunft Ressourcen sinnvoll verteilt werden können, sind Spitaldirektionen und Pflegeleitungen jedoch verstärkt auf solche Kennzahlen angewiesen. Methode/Design: Zur Durchführung dieser Evaluationsstudie wurde ein sequentiell-explanatives Mixed Methods Design gewählt. Während der Vorbereitungsphase, die im Frühjahr 2011 begann, wurden die notwendigen Instrumente ausgewählt und vorbereitet. Zudem wurde der Zugang zu den benötigten Patienten- und Pflegedaten gesichert, welche aus anderen Informationssystemen ins Monitoring übernommen wurden. Im Herbst

  5. Dorsal Root Ganglia Sensory Neuronal Cultures: a tool for drug discovery for peripheral neuropathies (United States)

    Melli, Giorgia; Höke, Ahmet


    Background Peripheral neuropathies affect many people worldwide and are caused by or associated with a wide range of conditions, both genetic and acquired. Current therapies are directed at symptomatic control because no effective regenerative treatment exists. Primary challenge is that mechanisms that lead to distal axonal degeneration, a common feature of all peripheral neuropathies, are largely unknown. Objective/Methods To address the role and specific characteristics of dorsal root ganglia (DRG) derived sensory neuron culture system as a useful model in evaluating the pathogenic mechanisms of peripheral neuropathies and examination and validation of potential therapeutic compounds. A thorough review of the recent literature was completed and select examples of the use of DRG neurons in different peripheral neuropathy models were chosen to highlight the utility of these cultures. Conclusion Many useful models of different peripheral neuropathies have been developed using DRG neuronal culture and potential therapeutic targets have been examined, but so far none of the potential therapeutic compounds have succeeded in clinical trials. In recent years, focus has changed to evaluation of axon degeneration as the primary outcome measure advocating a drug development strategy starting with phenotypic drug screening, followed by validation in primary complex co-cultures and animal models. PMID:20657751

  6. Taurine-induced modulation of voltage-sensitive Na+ channels in rat dorsal root ganglion neurons. (United States)

    Yu, Shan-Shan; Yu, Kuai; Gu, Yan; Ruan, Di-Yun


    The physiological role of taurine, an abundant free amino acid in the neural system, is still poorly understood. The aim of this study was to investigate its effect on TTX-sensitive (TTX-S) and TTX-resistant (TTX-R) Na+ currents in enzymatically dissociated neurons from rat dorsal root ganglion (DRG) with conventional whole-cell recording manner under voltage-clamp conditions. A TTX-S Na+ current was recorded preferentially from large DRG neurons and a TTX-R Na+ current preferentially from small ones. For TTX-S Na+ channel, taurine of the concentration > or = 10 mM shifted the activation curve in the depolarizing direction and the inactivation curve in the hyperpolarizing direction. There was no change in the activation curve for TTX-R Na+ channel and the inactivation curve was shifted in the hyperpolarizing direction slightly in the presence of taurine > or = 20 mM. When the recovery kinetics was examined, the presence of taurine resulted in a slower recovery from inactivation of TTX-S currents and no change of TTX-R ones. All the effects of taurine were weakly concentration-dependent and partly recovered quite slowly after washout. Our data indicate that taurine alters the properties of Na+ currents in intact DRG neurons. These may contribute to the understanding of taurine as a natural neuroprotectant and the potential of taurine as a useful medicine for the treatment of sensory neuropathies.

  7. Statins decrease expression of the proinflammatory neuropeptides calcitonin gene-related peptide and substance P in sensory neurons. (United States)

    Bucelli, Robert C; Gonsiorek, Eugene A; Kim, Woo-Yang; Bruun, Donald; Rabin, Richard A; Higgins, Dennis; Lein, Pamela J


    Clinical and experimental observations suggest that statins may be useful for treating diseases presenting with predominant neurogenic inflammation, but the mechanism(s) mediating this potential therapeutic effect are poorly understood. In this study, we tested the hypothesis that statins act directly on sensory neurons to decrease expression of proinflammatory neuropeptides that trigger neurogenic inflammation, specifically calcitonin gene-related peptide (CGRP) and substance P. Reverse transcriptase-polymerase chain reaction, radioimmunoassay, and immunocytochemistry were used to quantify CGRP and substance P expression in dorsal root ganglia (DRG) harvested from adult male rats and in primary cultures of sensory neurons derived from embryonic rat DRG. Systemic administration of statins at pharmacologically relevant doses significantly reduced CGRP and substance P levels in DRG in vivo. In cultured sensory neurons, statins blocked bone morphogenetic protein (BMP)-induced CGRP and substance P expression and decreased expression of these neuropeptides in sensory neurons pretreated with BMPs. These effects were concentration-dependent and occurred independent of effects on cell survival or axon growth. Statin inhibition of neuropeptide expression was reversed by supplementation with mevalonate and cholesterol, but not isoprenoid precursors. BMPs signal via Smad activation, and cholesterol depletion by statins inhibited Smad1 phosphorylation and nuclear translocation. These findings identify a novel action of statins involving down-regulation of proinflammatory neuropeptide expression in sensory ganglia via cholesterol depletion and decreased Smad1 activation and suggest that statins may be effective in attenuating neurogenic inflammation.

  8. Accumulation of Misfolded SOD1 in Dorsal Root Ganglion Degenerating Proprioceptive Sensory Neurons of Transgenic Mice with Amyotrophic Lateral Sclerosis

    Directory of Open Access Journals (Sweden)

    Javier Sábado


    Full Text Available Amyotrophic lateral sclerosis (ALS is an adult-onset progressive neurodegenerative disease affecting upper and lower motoneurons (MNs. Although the motor phenotype is a hallmark for ALS, there is increasing evidence that systems other than the efferent MN system can be involved. Mutations of superoxide dismutase 1 (SOD1 gene cause a proportion of familial forms of this disease. Misfolding and aggregation of mutant SOD1 exert neurotoxicity in a noncell autonomous manner, as evidenced in studies using transgenic mouse models. Here, we used the SOD1G93A mouse model for ALS to detect, by means of conformational-specific anti-SOD1 antibodies, whether misfolded SOD1-mediated neurotoxicity extended to neuronal types other than MNs. We report that large dorsal root ganglion (DRG proprioceptive neurons accumulate misfolded SOD1 and suffer a degenerative process involving the inflammatory recruitment of macrophagic cells. Degenerating sensory axons were also detected in association with activated microglial cells in the spinal cord dorsal horn of diseased animals. As large proprioceptive DRG neurons project monosynaptically to ventral horn MNs, we hypothesise that a prion-like mechanism may be responsible for the transsynaptic propagation of SOD1 misfolding from ventral horn MNs to DRG sensory neurons.

  9. Effect of NGF, BDNF, bFGF, aFGF and cell density on NPY expression in cultured rat dorsal root ganglion neurones. (United States)

    Kerekes, N; Landry, M; Lundmark, K; Hökfelt, T


    The effect of neurotrophic factors on neuropeptide Y (NPY) expression was studied in adult rat dispersed dorsal root ganglion (DRG) cultures. Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), acidic fibroblast growth factor (aFGF) or basic FGF was included in the culture medium during incubation for 72 h. In untreated cultures, around 18% of all neurones (visualized by antibodies to PGP 9.5) expressed NPY-like immunoreactivity (LI). In contrast, in vivo uninjured neurones do not contain detectable levels of NPY-LI. In the immunohistochemical analysis aFGF increased the percentage of NPY-immunoreactive (-IR) neurones 1.8-fold, while NGF, BDNF or bFGF had no significant effect on NPY expression. When the effect of these growth factors was monitored with non-radioactive in situ hybridization, both aFGF and bFGF caused a significant increase (2.25- and 1.8-fold, respectively), whereas, again, NGF and BDNF had no effect. The results also showed an effect of cell density on NPY expression, whereby fewer neurones expressed NPY in high than in low density cultures. This difference was seen in untreated as well as growth factor-treated cultures. The present results support the hypothesis that DRG neurones in culture are in an axotomized state, since they express NPY to about the same extent as axotomized DRG neurones in vivo. Surprisingly, two growth factors of the FGF family enhance NPY expression in DRG neurones, which is in apparent contrast to a published in vivo study [Ji, R.-R., Zhang, Q., Pettersson, R.F., Hökfelt, T., 1996. aFGF, bFGF and NGF differentially regulate neuropeptide expression in dorsal root ganglia after axotomy and induce autotomy. Reg. Pept. 66, 179-189.]. Finally, NPY expression was also influenced by cell density.

  10. Simulating pancreatic neuroplasticity: in vitro dual-neuron plasticity assay. (United States)

    Demir, Ihsan Ekin; Tieftrunk, Elke; Schäfer, Karl-Herbert; Friess, Helmut; Ceyhan, Güralp O


    Neuroplasticity is an inherent feature of the enteric nervous system and gastrointestinal (GI) innervation under pathological conditions. However, the pathophysiological role of neuroplasticity in GI disorders remains unknown. Novel experimental models which allow simulation and modulation of GI neuroplasticity may enable enhanced appreciation of the contribution of neuroplasticity in particular GI diseases such as pancreatic cancer (PCa) and chronic pancreatitis (CP). Here, we present a protocol for simulation of pancreatic neuroplasticity under in vitro conditions using newborn rat dorsal root ganglia (DRG) and myenteric plexus (MP) neurons. This dual-neuron approach not only permits monitoring of both organ-intrinsic and -extrinsic neuroplasticity, but also represents a valuable tool to assess neuronal and glial morphology and electrophysiology. Moreover, it allows functional modulation of supplied microenvironmental contents for studying their impact on neuroplasticity. Once established, the present neuroplasticity assay bears the potential of being applicable to the study of neuroplasticity in any GI organ.

  11. Increased response to glutamate in small diameter dorsal root ganglion neurons after sciatic nerve injury.

    Directory of Open Access Journals (Sweden)

    Kerui Gong

    Full Text Available Glutamate in the peripheral nervous system is involved in neuropathic pain, yet we know little how nerve injury alters responses to this neurotransmitter in primary sensory neurons. We recorded neuronal responses from the ex-vivo preparations of the dorsal root ganglia (DRG one week following a chronic constriction injury (CCI of the sciatic nerve in adult rats. We found that small diameter DRG neurons (30 µm were unaffected. Puff application of either glutamate, or the selective ionotropic glutamate receptor agonists alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA and kainic acid (KA, or the group I metabotropic receptor (mGluR agonist (S-3,5-dihydroxyphenylglycine (DHPG, induced larger inward currents in CCI DRGs compared to those from uninjured rats. N-methyl-D-aspartate (NMDA-induced currents were unchanged. In addition to larger inward currents following CCI, a greater number of neurons responded to glutamate, AMPA, NMDA, and DHPG, but not to KA. Western blot analysis of the DRGs revealed that CCI resulted in a 35% increase in GluA1 and a 60% decrease in GluA2, the AMPA receptor subunits, compared to uninjured controls. mGluR1 receptor expression increased by 60% in the membrane fraction, whereas mGluR5 receptor subunit expression remained unchanged after CCI. These results show that following nerve injury, small diameter DRG neurons, many of which are nociceptive, have increased excitability and an increased response to glutamate that is associated with changes in receptor expression at the neuronal membrane. Our findings provide further evidence that glutamatergic transmission in the periphery plays a role in nociception.

  12. Predictors of High Profit and High Deficit Outliers under SwissDRG of a Tertiary Care Center.

    Directory of Open Access Journals (Sweden)

    Tarun Mehra

    Full Text Available Case weights of Diagnosis Related Groups (DRGs are determined by the average cost of cases from a previous billing period. However, a significant amount of cases are largely over- or underfunded. We therefore decided to analyze earning outliers of our hospital as to search for predictors enabling a better grouping under SwissDRG.28,893 inpatient cases without additional private insurance discharged from our hospital in 2012 were included in our analysis. Outliers were defined by the interquartile range method. Predictors for deficit and profit outliers were determined with logistic regressions. Predictors were shortlisted with the LASSO regularized logistic regression method and compared to results of Random forest analysis. 10 of these parameters were selected for quantile regression analysis as to quantify their impact on earnings.Psychiatric diagnosis and admission as an emergency case were significant predictors for higher deficit with negative regression coefficients for all analyzed quantiles (p<0.001. Admission from an external health care provider was a significant predictor for a higher deficit in all but the 90% quantile (p<0.001 for Q10, Q20, Q50, Q80 and p = 0.0017 for Q90. Burns predicted higher earnings for cases which were favorably remunerated (p<0.001 for the 90% quantile. Osteoporosis predicted a higher deficit in the most underfunded cases, but did not predict differences in earnings for balanced or profitable cases (Q10 and Q20: p<0.00, Q50: p = 0.10, Q80: p = 0.88 and Q90: p = 0.52. ICU stay, mechanical and patient clinical complexity level score (PCCL predicted higher losses at the 10% quantile but also higher profits at the 90% quantile (p<0.001.We suggest considering psychiatric diagnosis, admission as an emergency case and admission from an external health care provider as DRG split criteria as they predict large, consistent and significant losses.

  13. Effect of down-regulation of voltage-gated sodium channel Nav1.7 on activation of astrocytes and microglia in DRG in rats with cancer pain

    Institute of Scientific and Technical Information of China (English)

    Jun Pan; Xiang-Jin Lin; Zhi-Heng Ling; You-Zhi Cai


    Objective:To evaluate the effect of down-regulation of Nav1.7 on the activation of astrocytes and microglia in DRG of rats with cancer pain, and explore the transmission of the nociceptive information.Methods:Lentiviral vector harboring RNAi sequence targeting theNav1.7gene was constructed, and Walker 256 breast cancer cell and morphine was injected to build the bone cancer pain model and morphine tolerance model in rats. Lentiviral vector was injected. Rats in each model were divided into 4 groups: model group, PBS group, vehicle group and LV-Nav1.7 group. The expression levels of GFAP and OX42 in dorsal root ganglia (DRG) were measured.Results: After the animal model was built,the level of Nav1.7, GFAP and OX42 was improved obviously with the time prolonged, which was statistically significant (P<0.05). The expression level of GFAP and OX42 in the DRG in the LV-Nav1.7 group declined obviously compared to the model group, PBS group and vehicle group (P<0.05).Conclusions:Intrathecal injection of Navl.7 shRNA lentiviral vector can reduce the expression of Nav1.7 and inhibit the activation of astrocytes and microglia in DRG. The effort is also effective in morphine tolerance bone cancer pain model rats.

  14. Effect of FGF-2 and sciatic nerve grafting on ChAT expression in dorsal root ganglia neurons of spinal cord transected rats. (United States)

    Guzen, Fausto Pierdoná; de Araújo, Dayane Pessoa; Lucena, Eudes Euler de Souza; de Morais, Hécio Henrique Araújo; Cavalcanti, José Rodolfo Lopes de Paiva; do Nascimento, Expedito Silva; Costa, Miriam Stela Maris de Oliveira; Cavalcante, Jeferson Sousa


    Neurotrophic factors and peripheral nerves are known to be good substrates for bridging CNS trauma. The involvement of fibroblast growth factor-2 (FGF-2) activation in the dorsal root ganglion (DRG) was examined following spinal cord injury in the rat. We evaluated whether FGF-2 increases the ability of a sciatic nerve graft to enhance neuronal plasticity, in a gap promoted by complete transection of the spinal cord. The rats were subjected to a 4mm-long gap at low thoracic level and were repaired with saline (Saline or control group, n=10), or fragment of the sciatic nerve (Nerve group, n=10), or fragment of the sciatic nerve to which FGF-2 (Nerve+FGF-2 group, n=10) had been added immediately after lesion. The effects of the FGF-2 and fragment of the sciatic nerve grafts on neuronal plasticity were investigated using choline acetyl transferase (ChAT)-immunoreactivity of neurons in the dorsal root ganglion after 8 weeks. Preservation of the area and diameter of neuronal cell bodies in dorsal root ganglion (DRG) was seen in animals treated with the sciatic nerve, an effect enhanced by the addition of FGF-2. Thus, the addition of exogenous FGF-2 to a sciatic nerve fragment grafted in a gap of the rat spinal cord submitted to complete transection was able to improve neuroprotection in the DRG. The results emphasized that the manipulation of the microenvironment in the wound might amplify the regenerative capacity of peripheral neurons.

  15. Prostaglandin E2 potentiation of P2X3 receptor mediated currents in dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Huang Li-Yen


    Full Text Available Abstract Prostaglandin E2 (PGE2 is a well-known inflammatory mediator that enhances the excitability of DRG neurons. Homomeric P2X3 and heteromeric P2X2/3 receptors are abundantly expressed in dorsal root ganglia (DRG neurons and participate in the transmission of nociceptive signals. The interaction between PGE2 and P2X3 receptors has not been well delineated. We studied the actions of PGE2 on ATP-activated currents in dissociated DRG neurons under voltage-clamp conditions. PGE2 had no effects on P2X2/3 receptor-mediated responses, but significantly potentiated fast-inactivating ATP currents mediated by homomeric P2X3 receptors. PGE2 exerted its action by activating EP3 receptors. To study the mechanism underlying the action of PGE2, we found that the adenylyl cyclase activator, forskolin and the membrane-permeable cAMP analogue, 8-Br-cAMP increased ATP currents, mimicking the effect of PGE2. In addition, forskolin occluded the enhancement produced by PGE2. The protein kinase A (PKA inhibitors, H89 and PKA-I blocked the PGE2 effect. In contrast, the PKC inhibitor, bisindolymaleimide (Bis did not change the potentiating action of PGE2. We further showed that PGE2 enhanced α,β-meATP-induced allodynia and hyperalgesia and the enhancement was blocked by H89. These observations suggest that PGE2 binds to EP3 receptors, resulting in the activation of cAMP/PKA signaling pathway and leading to an enhancement of P2X3 homomeric receptor-mediated ATP responses in DRG neurons.

  16. Tumor necrosis factor-α inhibits angiotensin II receptor type 1 expression in dorsal root ganglion neurons via β-catenin signaling. (United States)

    Yang, Y; Wu, H; Yan, J-Q; Song, Z-B; Guo, Q-L


    Both tumor necrosis factor (TNF)-α and the angiotensin (Ang) II/angiotensin II receptor type 1 (AT1) axis play important roles in neuropathic pain and nociception. In the present study, we explored the interaction between the two systems by examining the mutual effects between TNF-α and the Ang II/AT1 receptor axis in dorsal root ganglion (DRG) neurons. Rat DRG neurons were treated with TNF-α in different concentrations for different lengths of time in the presence or absence of transcription inhibitor actinomycin D, TNF receptor 1 (TNFR1) inhibitor SPD304, β-catenin signaling inhibitor CCT031374, or different kinase inhibitors. TNF-α decreased the AT1 receptor mRNA level as well as the AT1a receptor promoter activity in a dose-dependent manner within 30 h, which led to dose-dependent inhibition of Ang II-binding AT1 receptor level on the cell membrane. Actinomycin D (1 mg/ml), SPD304 (50 μM), p38 mitogen-activated protein kinase (MAPK) inhibitor PD169316 (25 μM), and CCT031374 (50 μM) completely abolished the inhibitory effect of TNF-α on AT1 receptor expression. TNF-α dose-dependently increased soluble β-catenin and phosphorylated GSK-3β levels, which was blocked by SPD304 and PD169316. In DRG neurons treated with AT2 receptor agonist CGP421140, or Ang II with or without AT1 receptor antagonist losartan or AT2 receptor antagonist PD123319 for 30 h, we found that Ang II and Ang II+PD123319 significantly decreased TNF-α expression, whereas CPG421140 and Ang II+losartan increased TNF-α expression. In conclusion, we demonstrate that TNF-α inhibits AT1 receptor expression at the transcription level via TNFR1 in rat DRG neurons by increasing the soluble β-catenin level through the p38 MAPK/GSK-3β pathway. In addition, Ang II appears to inhibit and induce TNF-α expression via the AT1 receptor and the AT2 receptor in DRG neurons, respectively. This is the first evidence of crosstalk between TNF-α and the Ang II/AT receptor axis in DRG neurons.

  17. Detection of basal and potassium-evoked acetylcholine release from embryonic DRG explants. (United States)

    Bernardini, Nadia; Tomassy, Giulio Srubek; Tata, Ada Maria; Augusti-Tocco, Gabriella; Biagioni, Stefano


    Spontaneous and potassium-induced acetylcholine release from embryonic (E12 and E18) chick dorsal root ganglia explants at 3 and 7 days in culture was investigated using a chemiluminescent procedure. A basal release ranging from 2.4 to 13.8 pm/ganglion/5 min was detected. Potassium application always induced a significant increase over the basal release. The acetylcholine levels measured in E12 explants were 6.3 and 38.4 pm/ganglion/5 min at 3 and 7 days in culture, respectively, while in E18 explant cultures they were 10.7 and 15.5 pm/ganglion/5 min. In experiments performed in the absence of extracellular Ca2+ ions, acetylcholine release, both basal and potassium-induced, was abolished and it was reduced by cholinergic antagonists. A morphometric analysis of explant fibre length suggested that acetylcholine release was directly correlated to neurite extension. Moreover, treatment of E12 dorsal root ganglion-dissociated cell cultures with carbachol as cholinergic receptor agonist was shown to induce a higher neurite outgrowth compared with untreated cultures. The concomitant treatment with carbachol and the antagonists at muscarinic receptors atropine and at nicotinic receptors mecamylamine counteracted the increase in fibre outgrowth. Although the present data have not established whether acetylcholine is released by neurones or glial cells, these observations provide the first evidence of a regulated release of acetylcholine in dorsal root ganglia.

  18. Lifting the weight of a diagnosis-related groups family change: a comparison between refined and non-refined DRG systems for top-down cost accounting and efficiency indicators. (United States)

    Zlotnik, Alexander; Cuchi, Miguel Alfaro; Pérez Pérez, Maria Carmen


    Public healthcare providers in all Spanish Regions - Autonomous Communities (ACs) use All Patients Diagnosis-Related Groups (AP-DRGs) for billing non-insured patients, cost accounting and inpatient efficiency indicators. A national migration to All Patients Refined Diagnosis-Related Groups (APR-DRGs) has been scheduled for 2016. The analysis was performed on 202,912 inpatient care episodes ranging from 2005 to 2010. All episodes were grouped using AP-DRG v25.0 and APR-DRG v24.0. Normalised DRG weight variations for an AP-DRG to APR-DRG migration scenario were calculated and compared. Major differences exist between normalised weights for inpatient episodes depending on the DRGs family used. The usage of the APR-DRG system in Spain without any adjustments, as it was developed in the United States, should be approached with care. In order to avoid reverse incentives and provider financial risks, coding practices should be reviewed and structural differences between DRG families taken into account.

  19. Heterogeneity of European DRG Systems and Potentials for a Common Eurodrg System; Comment on “Cholecystectomy and Diagnosis-Related Groups (DRGs: Patient Classification and Hospital Reimbursement in 11 European Countries”

    Directory of Open Access Journals (Sweden)

    Alexander Geissler


    Full Text Available Diagnosis-Related Group (DRG systems across Europe are very heterogeneous, in particular because of different classification variables and algorithms as well as costing methodologies. But, given the challenge of increasing patient mobility within Europe, health systems are forced to incorporate a common patient classification language in order to compare and identify similar patients e.g. for reimbursement purposes. Beside the national adoption of DRGs for a wide range of purposes (measuring hospital activity vs. paying hospitals, a common DRG system can serve as an international communication basis among health administrators and can reduce the national development efforts as it is demonstrated by the NordDRG consortium.

  20. Quantitative Analysis of Rat Dorsal Root Ganglion Neurons Cultured on Microelectrode Arrays Based on Fluorescence Microscopy Image Processing. (United States)

    Mari, João Fernando; Saito, José Hiroki; Neves, Amanda Ferreira; Lotufo, Celina Monteiro da Cruz; Destro-Filho, João-Batista; Nicoletti, Maria do Carmo


    Microelectrode Arrays (MEA) are devices for long term electrophysiological recording of extracellular spontaneous or evocated activities on in vitro neuron culture. This work proposes and develops a framework for quantitative and morphological analysis of neuron cultures on MEAs, by processing their corresponding images, acquired by fluorescence microscopy. The neurons are segmented from the fluorescence channel images using a combination of segmentation by thresholding, watershed transform, and object classification. The positioning of microelectrodes is obtained from the transmitted light channel images using the circular Hough transform. The proposed method was applied to images of dissociated culture of rat dorsal root ganglion (DRG) neuronal cells. The morphological and topological quantitative analysis carried out produced information regarding the state of culture, such as population count, neuron-to-neuron and neuron-to-microelectrode distances, soma morphologies, neuron sizes, neuron and microelectrode spatial distributions. Most of the analysis of microscopy images taken from neuronal cultures on MEA only consider simple qualitative analysis. Also, the proposed framework aims to standardize the image processing and to compute quantitative useful measures for integrated image-signal studies and further computational simulations. As results show, the implemented microelectrode identification method is robust and so are the implemented neuron segmentation and classification one (with a correct segmentation rate up to 84%). The quantitative information retrieved by the method is highly relevant to assist the integrated signal-image study of recorded electrophysiological signals as well as the physical aspects of the neuron culture on MEA. Although the experiments deal with DRG cell images, cortical and hippocampal cell images could also be processed with small adjustments in the image processing parameter estimation.

  1. A {beta} - {gamma} coincidence; Metodo de coincidencias {beta} - {gamma}

    Energy Technology Data Exchange (ETDEWEB)

    Agullo, F.


    A {beta} - {gamma} coincidence method for absolute counting is given. The fundamental principles are revised and the experimental part is detailed. The results from {sup 1}98 Au irradiated in the JEN 1 Swimming pool reactor are given. The maximal accuracy is 1 per cent. (Author) 11 refs.

  2. Increased response of muscle sensory neurons to decreases in pH after muscle inflammation. (United States)

    Gautam, M; Benson, C J; Sluka, K A


    Acid sensing ion channels (ASIC) are found in sensory neurons, including those that innervate muscle tissue. After peripheral inflammation there is an increase in proton concentration in the inflamed tissue, which likely activates ASICs. Previous studies from our laboratory in an animal model of muscle inflammation show that hyperalgesia does not occur in ASIC3 and ASIC1 knockout mice. Therefore, in the present study we investigated if pH activated currents in sensory neurons innervating muscle are altered after induction of muscle inflammation. Sensory neurons innervating mouse (C57/Bl6) muscle were retrogradely labeled with 1,1-dioctadecyl-3,3,3,3 tetramethylindocarbocyanine perchlorate (DiI). Two weeks after injection of DiI, mice were injected with 3% carrageenan to induce inflammation (n=8; 74 neurons) or pH 7.2 saline (n=5; 40 neurons, control) into the gastrocnemius muscle. 24 h later sensory neurons from L4-L6 dorsal root ganglia (DRG) were isolated and cultured. The following day the DRG neuron cultures were tested for responses to pH by whole-cell patch-clamp technique. Approximately 40% of neurons responded to pH 5 with an inward rapidly desensitizing current consistent with ASIC channels in both groups. The mean pH-evoked current amplitudes were significantly increased in muscle sensory neurons from inflamed mice (pH 5.0, 3602 ± 470 pA) in comparison to the controls (pH 7.4, 1964 ± 370 pA). In addition, the biophysical properties of ASIC-like currents were altered after inflammation. Changes in ASIC channels result in enhanced responsiveness to decreases in pH, and likely contribute to the increased hyperalgesia observed after muscle inflammation.

  3. Segmental distribution and morphometric features of primary sensory neurons projecting to the tibial periosteum in the rat.

    Directory of Open Access Journals (Sweden)

    Tadeusz Cichocki


    Full Text Available Previous reports have demonstrated very rich innervation pattern in the periosteum. Most of the periosteal fibers were found to be sensory in nature. The aim of this study was to identify the primary sensory neurons that innervate the tibial periosteum in the adult rat and to describe the morphometric features of their perikarya. To this end, an axonal fluorescent carbocyanine tracer, DiI, was injected into the periosteum on the medial surface of the tibia. The perikarya of the sensory fibers were traced back in the dorsal root ganglia (DRG L1-L6 by means of fluorescent microscopy on cryosections. DiI-containing neurons were counted in each section and their segmental distribution was determined. Using PC-assisted image analysis system, the size and shape of the traced perikarya were analyzed. DiI-labeled sensory neurons innervating the periosteum of the tibia were located in the DRG ipsilateral to the injection site, with the highest distribution in L3 and L4 (57% and 23%, respectively. The majority of the traced neurons were of small size (area < 850 microm2, which is consistent with the size distribution of CGRP- and SP-containing cells, regarded as primary sensory neurons responsible for perception of pain and temperature. A small proportion of labeled cells had large perikarya and probably supplied corpuscular sense receptors observed in the periosteum. No differences were found in the shape distribution of neurons belonging to different size classes.

  4. Introduction of a Diagnosis Related Groups’ Case Flat Rate System: Hopes and Fears (einfuerhrng eines drg-fallpauschalensystems - hoffnungen und aengste) (United States)


    Gesetzgeber ,,16st" - 1lst hier in dicken Anfahrungszeichen - dieses bekannte Problem mit einem Satz, nimlich Satz 2 in § 17 b Abs. 1 KHG : ,,Das...System sich Deutschland ausrichten wird. In § 17 b Abs. 2 KHG ist ledig- lich geregelt, dalR es ein ,,international bereits eingesetztes Verg(•tungs...Herbert Franz - 5KG 5 - 53 - * Schwierigkeiten fuir die Selbst- verwaltung: ,,Rahmenbedingungen" zum DRG- Verguitungssystem liegen nicht fest, da KHG

  5. 体外原代培养小鼠胚胎背根神经节细胞的神经化学特征%Neurochemical characteristics of cultured primary neurons from embryonic mouse dorsal root ganglia

    Institute of Scientific and Technical Information of China (English)

    李夏青; Julie A Coffield; 王志如; 张宏


    目的 探讨胚胎背根神经节(DRG)感觉神经元作为体外研究神经多肽的细胞模型之有效性.方法 采用免疫荧光及相差显微技术对30只胚胎小鼠背跟神经节细胞选择性神经多肽的分布、细胞大小及其多肽表达与细胞大小之间的关系进行观察比较.结果 培养时间达3周龄的DRG细胞主要以中小直径(30~ 20μm)的细胞为主,与成年在体脊髓DRG细胞的形态多形性特征类似;选择性神经多肽(钙调素基因相关多肽、P物质、甘丙肽和nociceptin)的表达也随着体外培养时间的延长明显增强,且从早期仅在胞体部位表达到3周时细胞周围神经突起也出现显著免疫荧光阳性.此外,体外培养达到3周时,降钙素基因相关多肽和P物质主要在体积较小的神经细胞表达,与成年鼠DRG的分布特征一致.而甘丙肽与nociceptin在不同大小DRG神经元的表达没有像降钙素基因相关多肽和P物质一样随着培养时间的延长而出现明显改变.结论 胚胎小鼠DRG神经细胞培养可以作为研究感觉神经细胞某些重要的神经多肽(降钙素基因相关多肽,P物质)在调节感觉神经细胞内相关信号转导通路中作用的体外模型.%Objective Morphological heterogeneity and the expression of neuropeptides in the cultured primary neurons of the dorsal root ganglia from the embryonic mouse were investigated. Methods Morphology and neurochemistry of cultured dorsal root ganglia ( DRG) neurons were analyzed by phase-contrast microscopy and immnuofluorensence. Results Morphological characteristics of DRG neurons with a 3-week culture period appeared similar to those observed in adult DRG neurons. The ratio of median to small sized neurons (20 - 30μm) was increased from (8. 9 ± 0. 61) % after 1 -week culture to (29.58 ±1.23)% after 3-weeks culture. The selective neuropeptides, CGRP, substance-P, galanin and nociceptin, were expressed in neuron soma from the first week of the

  6. Sprouty2 down-regulation promotes axon growth by adult sensory neurons. (United States)

    Hausott, Barbara; Vallant, Natalie; Auer, Maria; Yang, Lin; Dai, Fangping; Brand-Saberi, Beate; Klimaschewski, Lars


    Fibroblast growth factors (FGFs) play a prominent role in axonal growth during development and repair. Treatment with FGF-2 or overexpression of FGF receptors promotes peripheral axon regeneration mainly by activation of extracellular signal-regulated kinase (ERK). The Ras/Raf/ERK pathway is under the control of Sprouty proteins acting as negative feedback inhibitors. We investigated the expression of Sprouty isoforms in adult sensory neurons of dorsal root ganglia (DRG) as well as the effects of Sprouty inhibition on axon growth by small interfering RNAs (siRNAs). Sprouty2 revealed the highest expression level in DRG neurons. Down-regulation of Sprouty2 promoted elongative axon growth by adult sensory neurons accompanied by enhanced FGF-2-induced activation of ERK and Ras, whereas Sprouty2 overexpression inhibited axon growth. Sprouty2 was not regulated in vivo in response to a sciatic nerve lesion. Together, our results imply that Sprouty2 is highly expressed in adult peripheral neurons and its down-regulation strongly promotes elongative axon growth by activation of the Ras/Raf/ERK pathway.

  7. Ciliary neurotrophic factor reverses aberrant mitochondrial bioenergetics through the JAK/STAT pathway in cultured sensory neurons derived from streptozotocin-induced diabetic rodents. (United States)

    Chowdhury, Subir Roy; Saleh, Ali; Akude, Eli; Smith, Darrell R; Morrow, Dwane; Tessler, Lori; Calcutt, Nigel A; Fernyhough, Paul


    Mitochondrial dysfunction occurs in sensory neurons and contributes to diabetic neuropathy. Ciliary neurotrophic factor (CNTF) stimulates axon regeneration in type 1 diabetic rodents and prevents deficits in axonal caliber, nerve conduction, and thermal sensation. We tested the hypothesis that CNTF enhances sensory neuron function in diabetes through JAK/STAT (Janus kinase/signal transducers and activators of transcription) signaling to normalize impaired mitochondrial bioenergetics. The effect of CNTF on gene expression and neurite outgrowth of cultured adult dorsal root ganglia (DRG) sensory neurons derived from control and streptozotocin (STZ)-induced diabetic rodents was quantified. Polarization status and bioenergetics profile of mitochondria from cultured sensory neurons were determined. CNTF treatment prevented reduced STAT3 phosphorylation (Tyr 705) in DRG of STZ-diabetic mice and also enhanced STAT3 phosphorylation in rat DRG cultures. CNTF normalized polarization status of the mitochondrial inner membrane and corrected the aberrant oligomycin-induced mitochondrial hyperpolarization in axons of diabetic neurons. The mitochondrial bioenergetics profile demonstrated that spare respiratory capacity and respiratory control ratio were significantly depressed in sensory neurons cultured from STZ-diabetic rats and were corrected by acute CNTF treatment. The positive effects of CNTF on neuronal mitochondrial function were significantly inhibited by the specific JAK inhibitor, AG490. Neurite outgrowth of sensory neurons from age-matched control and STZ-induced diabetic rats was elevated by CNTF and blocked by AG490. We propose that CNTF's ability to enhance axon regeneration and protect from fiber degeneration in diabetes is associated with its targeting of mitochondrial function and improvement of cellular bioenergetics, in part, through JAK/STAT signaling.

  8. 阿霉素中毒大鼠背根神经节神经元及核孔的改变%Changes of nuclear pore and neurons in lumbar dorsal root ganglion of doxorubicin- intoxicated rats

    Institute of Scientific and Technical Information of China (English)

    赫秋月; 韩漫夫; 大西晃生


    Objective To study how Doxorubicin (DXR) causes degeneration of neurons in the lumbar dorsal root ganglion (DRG) in rats.Methods Light microscopic studies, which included the terminal deoxynucleotidyl transferase- mediated deoxyuridine triphosphate- biotin nick end labeling method, and electron microscopic observation revealed that the moderate nuclear and remarkeble cytoplasmic degeneration of DRG neurons of Sprague- Dawley rats after intravenous administration of 8 mg/kg of DXR was cell necrosis, not apoptosis.Results In some neurons, mostly dark and usually with moderate degrees of nuclear degenerative changes, the nuclear pores were decreased in number and obscure 14 and 20 days after DXR administration. DXR enters presumabley the nucleus and is partly removed through the nuclear pores. However, the diameters of nuclear pores were similar in DXR- intoxicated and control rats.Conclusion The changes in nuclear pores of neurons in DXR intoxication, which to our knowledge has not been previously studied, are considered to be part of the degenerative or necrotic changes of DRG neurons.

  9. TRPA1 is functionally expressed primarily by IB4-binding, non-peptidergic mouse and rat sensory neurons.

    Directory of Open Access Journals (Sweden)

    Marie E Barabas

    Full Text Available Subpopulations of somatosensory neurons are characterized by functional properties and expression of receptor proteins and surface markers. CGRP expression and IB4-binding are commonly used to define peptidergic and non-peptidergic subpopulations. TRPA1 is a polymodal, plasma membrane ion channel that contributes to mechanical and cold hypersensitivity during tissue injury, making it a key target for pain therapeutics. Some studies have shown that TRPA1 is predominantly expressed by peptidergic sensory neurons, but others indicate that TRPA1 is expressed extensively within non-peptidergic, IB4-binding neurons. We used FURA-2 calcium imaging to define the functional distribution of TRPA1 among peptidergic and non-peptidergic adult mouse (C57BL/6J DRG neurons. Approximately 80% of all small-diameter (<27 µm neurons from lumbar 1-6 DRGs that responded to TRPA1 agonists allyl isothiocyanate (AITC; 79% or cinnamaldehyde (84% were IB4-positive. Retrograde labeling via plantar hind paw injection of WGA-Alexafluor594 showed similarly that most (81% cutaneous neurons responding to TRPA1 agonists were IB4-positive. Additionally, we cultured DRG neurons from a novel CGRP-GFP mouse where GFP expression is driven by the CGRPα promoter, enabling identification of CGRP-expressing live neurons. Interestingly, 78% of TRPA1-responsive neurons were CGRP-negative. Co-labeling with IB4 revealed that the majority (66% of TRPA1 agonist responders were IB4-positive but CGRP-negative. Among TRPA1-null DRGs, few small neurons (2-4% responded to either TRPA1 agonist, indicating that both cinnamaldehyde and AITC specifically target TRPA1. Additionally, few large neurons (≥27 µm diameter responded to AITC (6% or cinnamaldehyde (4%, confirming that most large-diameter somata lack functional TRPA1. Comparison of mouse and rat DRGs showed that the majority of TRPA1-responsive neurons in both species were IB4-positive. Together, these data demonstrate that TRPA1 is

  10. Prokaryotic expression of recombinant human p75NTR-Fc fusion protein and its effect on the neurite outgrowth of dorsal root ganglia neuron

    Institute of Scientific and Technical Information of China (English)

    Zhu Feng; Wang Yongtang; Lu Xiumin; Zeng Lin; Wu Yamin


    Objective: To clone, express, and identify the extracellular domain gene of human p75 neurotrophin receptor with IgG-Fc (hp75NTR-Fc) in prokaryotic expression system, and investigate the effect of the recombinant protein on dorsal root ganglia (DRG) neuron neurites. Methods: The hp75NTR-Fc coding sequence was amplified from pcDNA-hp75NTR-Fc by polymerase chain reaction (PCR) and subcloned into vector pET30a (+), in which hp75NTR-Fc expression was controlled under the T7 promoter. The recombinant vectors were amplified in E. coli DH5a and identified by PCR, enzyme digestion and sequencing, and then transformed into E. coli BL21 (DE3). The expression product was analyzed with SDS-PAGE and Western blot. Then after the recombinant protein purified with Protein A affinity chromatograph, and renaturated with dialysis, respectively, the effect of the recombinant protein on DRG neuron neuritis was further investigated. Results: The results of PCR, enzyme digestion, and sequencing demonstrated the success of inserting the hp75NTR-Fc fragment into vector pET30a (+). SDS-PAGE and Western blot showed a positive protein band with molecular weight about 50 kD in the expression product, which is accordant with the interest protein, and this band could be specifically recognized by rabbit anti-NGFRp75 antibody. The purified infusion protein following dialysis could promote neurite outgrowth of DRG neurons cultured with myelin-associated glycoprotein (MAG). Conclusion: The hp75NTR-Fc coding sequence was subcloned into the expression vector pET30a (+) correctly and expressed successfully in the prokaryotic expression system. The infusion protein could promote neurite outgrowth of DRG neurons cultured with MAG.

  11. Modulation of dragon's blood on tetrodotoxin-resistant sodium currents in dorsal root ganglion neurons and identification of its material basis for efficacy

    Institute of Scientific and Technical Information of China (English)

    LIU; Xiangming; CHEN; Su; ZHANG; Yuxia


    To clarify the modulation of dragon's blood on the tetrodotoxin-resistant (TTX-R) sodium currents in dorsal root ganglion (DRG) neurons and explore its corresponding material basis for the efficacy, using whole-cell patch clamp technique, the effects of dragon's blood and the combined effects of three components (cochinchinenin A, cochinchinenin B, and loureirin B) extracted from dragon's blood on the TTX-R sodium currents in acute-isolated DRG neurons of rats were observed. According to the operational definition of material basis for the efficacy of TCM established, the material basis of the modulation on the TTX-R sodium currents in DRG neurons of dragon's blood was judged from the experimental results. The drug interaction equation of Greco et al. was used to assess the interaction of the three components extracted from dragon's blood. This investigation demonstrated that dragon's blood suppressed the peak TTX-R sodium currents in a dose-dependent way and affected the activations of TTX-R sodium currents. The effects of the combination of cochinchinenin A, cochinchinenin B, and loureirin B were in good agreement with those of dragon's blood. Although the three components used alone could modulate TTX-R sodium currents, the concentrations of the three components used alone were respectively higher than those used in combination when the inhibition rates on the TTX-R sodium currents of them used alone and in combination were the same. The combined effects of the three components were synergistic. These results suggested that the interference with pain messages caused by the modulation of dragon's blood on TTX-R sodium currents in DRG neurons may explain some of the analgesic effect of dragon's blood and the corresponding material basis for the efficacy is the combination of cochinchinenin A, cochinchinenin B, and loureirin B.

  12. Antinociceptive Effects of AGAP, a Recombinant Neurotoxic Polypeptide: Possible Involvement of the Tetrodotoxin-Resistant Sodium Channels in Small Dorsal Root Ganglia Neurons (United States)

    Li, Chun-Li; Liu, Xi-Fang; Li, Gui-Xia; Ban, Meng-qi; Chen, Jian-Zhao; Cui, Yong; Zhang, Jing-Hai; Wu, Chun-Fu


    Antitumor-analgesic peptide (AGAP) is a novel recombinant polypeptide. The primary study showed that AGAP 1.0 mg/kg exhibited strong analgesic and antitumor effects. The tail vein administration of AGAP potently reduced pain behaviors in mice induced by intraplantar injection of formalin or intraperitoneal injection of acetic acid, without affecting basal pain perception. To further assess the mechanisms of AGAP, the effects of AGAP on sodium channels were assessed using the whole-cell patch clamp recordings in dorsal root ganglia (DRG) neurons. The results showed that AGAP (3–1000 nM) inhibited the sodium currents in small-diameter DRG neurons in a dose-dependent manner. 1000 nM AGAP could inhibit the current density-voltage relationship curve of sodium channels in a voltage-dependent manner and negatively shift the activation curves. 1000 nM AGAP could reduce the tetrodotoxin-resistant (TTX-R) sodium currents by 42.8% in small-diameter DRG neurons. Further analysis revealed that AGAP potently inhibited NaV1.8 currents by 59.4%, and negatively shifted the activation and inactivation kinetics. 1000 nM AGAP also reduced the NaV1.9 currents by 33.7%, but had no significant effect on activation and inactivation kinetics. Thus, our results demonstrated that submicromolar concentrations of AGAP inhibited TTX-R sodium channel in rat small-diameter DRG neurons. It is concluded that these new results may better explain, at least in part, the analgesic properties of this polypeptide. PMID:28066245

  13. Antinociceptive effects of AGAP, a recombinant neurotoxic polypeptide: Possible involvement of the tetrodotoxin-resistant sodium channels in small dorsal root ganglia neurons

    Directory of Open Access Journals (Sweden)

    Li Chunli


    Full Text Available Antitumor-analgesic peptide(AGAP)is a novel recombinant polypeptide. The primary study showed that AGAP 1.0 mg/kg exhibited strong analgesic and antitumor effects. The tail vein administration of AGAP potently reduced pain behaviors in mice induced by intraplantar injection of formalin or intraperitoneal injection of acetic acid, without affecting basal pain perception. To further assess the mechanisms of AGAP, the effects of AGAP on sodium channels were assessed using the whole-cell patch clamp recordings in dorsal root ganglia (DRG neurons. The results showed that AGAP (3-1000 nM inhibited the sodium currents in small-diameter DRG neurons in a dose-dependent manner. 1000 nM AGAP could inhibit the current density-voltage relationship curve of sodium channels in a voltage-dependent manner and negatively shift the activation curves. 1000 nM AGAP could reduce the tetrodotoxin-resistant (TTX-R sodium currents by 42.8% in small-diameter DRG neurons. Further analysis revealed that AGAP potently inhibited NaV1.8 currents by 59.4%, and negatively shifted the activation and inactivation kinetics. 1000 nM AGAP also reduced the NaV1.9 currents by 33.7%, but had no significant effect on activation and inactivation kinetics. Thus, our results demonstrated that submicromolar concentrations of AGAP inhibited TTX-R sodium channel in rat small-diameter DRG neurons. It is concluded that these new results may better explain, at least in part, the analgesic properties of this polypeptide.

  14. Thy1.2 YFP-16 transgenic mouse labels a subset of large-diameter sensory neurons that lack TRPV1 expression.

    Directory of Open Access Journals (Sweden)

    Thomas E Taylor-Clark

    Full Text Available The Thy1.2 YFP-16 mouse expresses yellow fluorescent protein (YFP in specific subsets of peripheral and central neurons. The original characterization of this model suggested that YFP was expressed in all sensory neurons, and this model has been subsequently used to study sensory nerve structure and function. Here, we have characterized the expression of YFP in the sensory ganglia (DRG, trigeminal and vagal of the Thy1.2 YFP-16 mouse, using biochemical, functional and anatomical analyses. Despite previous reports, we found that YFP was only expressed in approximately half of DRG and trigeminal neurons and less than 10% of vagal neurons. YFP-expression was only found in medium and large-diameter neurons that expressed neurofilament but not TRPV1. YFP-expressing neurons failed to respond to selective agonists for TRPV1, P2X(2/3 and TRPM8 channels in Ca2+ imaging assays. Confocal analysis of glabrous skin, hairy skin of the back and ear and skeletal muscle indicated that YFP was expressed in some peripheral terminals with structures consistent with their presumed non-nociceptive nature. In summary, the Thy1.2 YFP-16 mouse expresses robust YFP expression in only a subset of sensory neurons. But this mouse model is not suitable for the study of nociceptive nerves or the function of such nerves in pain and neuropathies.

  15. Neuro-fuzzy decoding of sensory information from ensembles of simultaneously recorded dorsal root ganglion neurons for functional electrical stimulation applications (United States)

    Rigosa, J.; Weber, D. J.; Prochazka, A.; Stein, R. B.; Micera, S.


    Functional electrical stimulation (FES) is used to improve motor function after injury to the central nervous system. Some FES systems use artificial sensors to switch between finite control states. To optimize FES control of the complex behavior of the musculo-skeletal system in activities of daily life, it is highly desirable to implement feedback control. In theory, sensory neural signals could provide the required control signals. Recent studies have demonstrated the feasibility of deriving limb-state estimates from the firing rates of primary afferent neurons recorded in dorsal root ganglia (DRG). These studies used multiple linear regression (MLR) methods to generate estimates of limb position and velocity based on a weighted sum of firing rates in an ensemble of simultaneously recorded DRG neurons. The aim of this study was to test whether the use of a neuro-fuzzy (NF) algorithm (the generalized dynamic fuzzy neural networks (GD-FNN)) could improve the performance, robustness and ability to generalize from training to test sets compared to the MLR technique. NF and MLR decoding methods were applied to ensemble DRG recordings obtained during passive and active limb movements in anesthetized and freely moving cats. The GD-FNN model provided more accurate estimates of limb state and generalized better to novel movement patterns. Future efforts will focus on implementing these neural recording and decoding methods in real time to provide closed-loop control of FES using the information extracted from sensory neurons.

  16. Increased Nerve Growth Factor Signaling in Sensory Neurons of Early Diabetic Rats Is Corrected by Electroacupuncture

    Directory of Open Access Journals (Sweden)

    Stefania Lucia Nori


    Full Text Available Diabetic polyneuropathy (DPN, characterized by early hyperalgesia and increased nerve growth factor (NGF, evolves in late irreversible neuropathic symptoms with reduced NGF support to sensory neurons. Electroacupuncture (EA modulates NGF in the peripheral nervous system, being effective for the treatment of DPN symptoms. We hypothesize that NGF plays an important pathogenic role in DPN development, while EA could be useful in the therapy of DPN by modulating NGF expression/activity. Diabetes was induced in rats by streptozotocin (STZ injection. One week after STZ, EA was started and continued for three weeks. NGF system and hyperalgesia-related mediators were analyzed in the dorsal root ganglia (DRG and in their spinal cord and skin innervation territories. Our results show that four weeks long diabetes increased NGF and NGF receptors and deregulated intracellular signaling mediators of DRG neurons hypersensitization; EA in diabetic rats decreased NGF and NGF receptors, normalized c-Jun N-terminal and p38 kinases activation, decreased transient receptor potential vanilloid-1 ion channel, and possibly activated the nuclear factor kappa-light-chain-enhancer of activated B cells (Nf-κB. In conclusion, NGF signaling deregulation might play an important role in the development of DPN. EA represents a supportive tool to control DPN development by modulating NGF signaling in diabetes-targeted neurons.

  17. Temperature dependence of rapidly adapting mechanically activated currents in rat dorsal root ganglion neurons. (United States)

    Jia, Zhanfeng; Ling, Jennifer; Gu, Jianguo G


    Rapidly adapting mechanically activated channels (RA) are expressed on somatosensory neurons and thought to play a role in mechanical transduction. Because mechanical sensations can be significantly affected by temperatures, we examined thermal sensitivity of RA currents in cultured dorsal root ganglion (DRG) neurons to see if RA channel activity is highly temperature-dependent. RA currents were evoked from DRG neurons by membrane displacements and recorded by the whole-cell patch-clamp recording technique. We found that RA currents were significantly enhanced by warming temperatures from 22 to 32 °C and reduced by cooling temperatures from 24 to 14 °C. RA channel activation exhibited steep temperature-dependence with a large temperature coefficient (Q10>5) and a high activation energy (Ea>30 kcal/mol). We further showed that RA channel activation by mechanical stimulation led to membrane depolarization, which could result in action potential firing at 22 °C or 32 °C but not at 14 °C. Taken together, our results provide the measurements of thermal dynamics and activation energy of RA channels, and suggest that a high energy barrier is present for RA channels to open. These findings are in agreement with temperature sensitivity of mechanical sensations in mammals.

  18. Bone Injury and Repair Trigger Central and Peripheral NPY Neuronal Pathways (United States)

    Alencastre, Inês S.; Neto, Estrela; Ribas, João; Ferreira, Sofia; Vasconcelos, Daniel M.; Sousa, Daniela M.; Summavielle, Teresa; Lamghari, Meriem


    Bone repair is a specialized type of wound repair controlled by complex multi-factorial events. The nervous system is recognized as one of the key regulators of bone mass, thereby suggesting a role for neuronal pathways in bone homeostasis. However, in the context of bone injury and repair, little is known on the interplay between the nervous system and bone. Here, we addressed the neuropeptide Y (NPY) neuronal arm during the initial stages of bone repair encompassing the inflammatory response and ossification phases in femoral-defect mouse model. Spatial and temporal analysis of transcriptional and protein levels of NPY and its receptors, Y1R and Y2R, reported to be involved in bone homeostasis, was performed in bone, dorsal root ganglia (DRG) and hypothalamus after femoral injury. The results showed that NPY system activity is increased in a time- and space-dependent manner during bone repair. Y1R expression was trigged in both bone and DRG throughout the inflammatory phase, while a Y2R response was restricted to the hypothalamus and at a later stage, during the ossification step. Our results provide new insights into the involvement of NPY neuronal pathways in bone repair. PMID:27802308

  19. Conceptual design report for a Beta-Beam facility

    CERN Document Server

    Benedikt, M; Borgnolutti, F; Bouquerel, E; Bozyk, L; Bruer, J; Chance, A; Delahaye, P; Fabich, A; Hancock, S; Hansen, C; Jensen, E; Kallberg, A; Kirk, M; Lachaize, A; Lindroos, M; Loiselet, M; Magistris, M; Mitrofanov, S; Mueller, A C; Payet, J; Podlech, H; Puppel, P; Silari, M; Simonsson, A; Spiller, P; Stadlmann, J; Stora, T; Tkatchenko, A; Trovati, S; Vlachoudis, V; Wildner, E


    The Beta-Beam is a concept of large-scale facility that aims at providing pure electronic neutrino and antineutrino beams for the measurement of v(e) -> v(mu) oscillations. Beta-decaying nuclides are produced in large amounts in a facility of the scale of EURISOL, and are then post-accelerated and stored at large gamma in a racetrack decay ring. We present here a conceptual design of the accelerator chain of a Beta-Beam based at CERN.

  20. A Study to Identify Variables Contributing to Length of Stay for Selected Diagnosis Related Groups (DRG) at Madigan Army Medical Center (United States)


    Margolis, and Wise 1986). A total of 215 patients 0 0in DRG 162 ( inguinal and femoral hernia repair, age 18 to 69 years C• C0 m without complications...the 0.05 level for one of the four DRGs. 0• " C 0m Additional analysis revealed that the diagnostic group, type of anesthesia , use of consultations...Allergy/Immunology I 1 Anesthesia I 1 Child Psychology 1 1 Dermatology I Developmental Peds I Emergency Medicine I Endocrinology 1 1 o Facul Devel

  1. 4-Hydroxy-2-nonenal induces mitochondrial dysfunction and aberrant axonal outgrowth in adult sensory neurons that mimics features of diabetic neuropathy. (United States)

    Akude, Eli; Zherebitskaya, Elena; Roy Chowdhury, Subir K; Girling, Kimberly; Fernyhough, Paul


    Modification of proteins by 4-hydroxy-2-nonenal (4-HNE) has been proposed to cause neurotoxicity in a number of neurodegenerative diseases, including distal axonopathy in diabetic sensory neuropathy. We tested the hypothesis that exposure of cultured adult rat sensory neurons to 4-HNE would result in the formation of amino acid adducts on mitochondrial proteins and that this process would be associated with impaired mitochondrial function and axonal regeneration. In addition, we compared 4-HNE-induced axon pathology with that exhibited by neurons isolated from diabetic rats. Cultured adult rat dorsal root ganglion (DRG) sensory neurons were incubated with varying concentrations of 4-HNE. Cell survival, axonal morphology, and level of axon outgrowth were assessed. In addition, video microscopy of live cells, western blot, and immunofluorescent staining were utilized to detect protein adduct formation by 4-HNE and to localize actively respiring mitochondria. 4-HNE induced formation of protein adducts on cytoskeletal and mitochondrial proteins, and impaired axon regeneration by approximately 50% at 3 microM while having no effect on neuronal survival. 4-HNE initiated formation of aberrant axonal structures and caused the accumulation of mitochondria in these dystrophic structures. Neurons treated with 4-HNE exhibited a distal loss of active mitochondria. Finally, the distal axonopathy and the associated aberrant axonal structures generated by 4-HNE treatment mimicked axon pathology observed in DRG sensory neurons isolated from diabetic rats and replicated aspects of neurodegeneration observed in human diabetic sensory neuropathy.

  2. Antihyperalgesic effect of CB1 receptor activation involves the modulation of P2X3 receptor in the primary afferent neuron. (United States)

    Oliveira-Fusaro, Maria Cláudia Gonçalves; Zanoni, Cristiane Isabel Silva; Dos Santos, Gilson Gonçalves; Manzo, Luis Paulo; Araldi, Dionéia; Bonet, Ivan José Magayewski; Tambeli, Cláudia Herrera; Dias, Elayne Vieira; Parada, Carlos Amilcar


    Cannabinoid system is a potential target for pain control. Cannabinoid receptor 1 (CB1) activation play a role in the analgesic effect of cannabinoids once it is expressed in primary afferent neurons. This study investigates whether the anti-hyperalgesic effect of CB1 receptor activation involves P2X3 receptor in primary afferent neurons. Mechanical hyperalgesia was evaluated by electronic von Frey test. Cannabinoid effect was evaluated using anandamide or ACEA, a non-selective or a selective CB1 receptor agonists, respectively; AM251, a CB1 receptor antagonist, and antisense ODN for CB1 receptor. Calcium imaging assay was performed to evaluated α,β-meATP-responsive cultured DRG neurons pretreated with ACEA. Anandamide or ACEA administered in peripheral tissue reduced the carrageenan-induced mechanical hyperalgesia. The reduction in the carrageenan-induced hyperalgesia induced by ACEA was completely reversed by administration of AM251 as well as by the intrathecal treatment with antisense ODN for CB1 receptor. Also, ACEA reduced the mechanical hyperalgesia induced by bradykinin and by α,β-meATP, a P2X3 receptor non-selective agonist, but not by tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β) and chemokine-induced chemoattractant-1 (CINC-1). Finally, CB1 receptors are co-localized with P2X3 receptors in DRG small-diameter neurons and the treatment with ACEA reduced the number of α,β-meATP-responsive cultured DRG neurons. Our data suggest that the analgesic effect of CB1 receptor activation is mediated by a negative modulation of the P2X3 receptor in the primary afferent neurons.

  3. Long-term activation of group I metabotropic glutamate receptors increases functional TRPV1-expressing neurons in mouse dorsal root ganglia

    Directory of Open Access Journals (Sweden)

    Takayoshi eMasuoka


    Full Text Available Damaged tissues release glutamate and other chemical mediators for several hours. These chemical mediators contribute to modulation of pruritus and pain. Herein, we investigated the effects of long-term activation of excitatory glutamate receptors on functional expression of transient receptor potential vaniloid type 1 (TRPV1 in dorsal root ganglion (DRG neurons and then on thermal pain behavior. In order to detect the TRPV1-mediated responses in cultured DRG neurons, we monitored intracellular calcium responses to capsaicin, a TRPV1 agonist, with Fura-2. Long-term (4 h treatment with glutamate receptor agonists (glutamate, quisqualate or DHPG increased the proportion of neurons responding to capsaicin through activation of metabotropic glutamate receptor mGluR1, and only partially through the activation of mGluR5; engagement of these receptors was evident in neurons responding to allylisothiocyanate (AITC, a transient receptor potential ankyrin type 1 (TRPA1 agonist. Increase in the proportion was suppressed by phospholipase C, protein kinase C, mitogen/extracellular signal-regulated kinase, p38 mitogen-activated protein kinase or transcription inhibitors. Whole-cell recording was performed to record TRPV1-mediated membrane current; TRPV1 current density significantly increased in the AITC-sensitive neurons after the quisqualate treatment. To elucidate the physiological significance of this phenomenon, a hot plate test was performed. Intraplantar injection of quisqualate or DHPG induced heat hyperalgesia that lasted for 4 h post injection. This chronic hyperalgesia was attenuated by treatment with either mGluR1 or mGluR5 antagonists. These results suggest that long-term activation of mGluR1/5 by peripherally released glutamate may increase the number of neurons expressing functional TRPV1 in DRG, which may be strongly associated with chronic hyperalgesia.

  4. Association between tetrodotoxin resistant channels and lipid rafts regulates sensory neuron excitability.

    Directory of Open Access Journals (Sweden)

    Alessandro Pristerà

    Full Text Available Voltage-gated sodium channels (VGSCs play a key role in the initiation and propagation of action potentials in neurons. Na(V1.8 is a tetrodotoxin (TTX resistant VGSC expressed in nociceptors, peripheral small-diameter neurons able to detect noxious stimuli. Na(V1.8 underlies the vast majority of sodium currents during action potentials. Many studies have highlighted a key role for Na(V1.8 in inflammatory and chronic pain models. Lipid rafts are microdomains of the plasma membrane highly enriched in cholesterol and sphingolipids. Lipid rafts tune the spatial and temporal organisation of proteins and lipids on the plasma membrane. They are thought to act as platforms on the membrane where proteins and lipids can be trafficked, compartmentalised and functionally clustered. In the present study we investigated Na(V1.8 sub-cellular localisation and explored the idea that it is associated with lipid rafts in nociceptors. We found that Na(V1.8 is distributed in clusters along the axons of DRG neurons in vitro and ex vivo. We also demonstrated, by biochemical and imaging studies, that Na(V1.8 is associated with lipid rafts along the sciatic nerve ex vivo and in DRG neurons in vitro. Moreover, treatments with methyl-β-cyclodextrin (MβCD and 7-ketocholesterol (7KC led to the dissociation between rafts and Na(V1.8. By calcium imaging we demonstrated that the lack of association between rafts and Na(V1.8 correlated with impaired neuronal excitability, highlighted by a reduction in the number of neurons able to conduct mechanically- and chemically-evoked depolarisations. These findings reveal the sub-cellular localisation of Na(V1.8 in nociceptors and highlight the importance of the association between Na(V1.8 and lipid rafts in the control of nociceptor excitability.

  5. Effect of knockout of α2δ-1 on action potentials in mouse sensory neurons (United States)

    Margas, Wojciech; Ferron, Laurent; Nieto-Rostro, Manuela; Schwartz, Arnold; Dolphin, Annette C.


    Gene deletion of the voltage-gated calcium channel auxiliary subunit α2δ-1 has been shown previously to have a cardiovascular phenotype, and a reduction in mechano- and cold sensitivity, coupled with delayed development of neuropathic allodynia. We have also previously shown that dorsal root ganglion (DRG) neuron calcium channel currents were significantly reduced in α2δ-1 knockout mice. To extend our findings in these sensory neurons, we have examined here the properties of action potentials (APs) in DRG neurons from α2δ-1 knockout mice in comparison to their wild-type (WT) littermates, in order to dissect how the calcium channels that are affected by α2δ-1 knockout are involved in setting the duration of individual APs and their firing frequency. Our main findings are that there is reduced Ca2+ entry on single AP stimulation, particularly in the axon proximal segment, reduced AP duration and reduced firing frequency to a 400 ms stimulation in α2δ-1 knockout neurons, consistent with the expected role of voltage-gated calcium channels in these events. Furthermore, lower intracellular Ca2+ buffering also resulted in reduced AP duration, and a lower frequency of AP firing in WT neurons, mimicking the effect of α2δ-1 knockout. By contrast, we did not obtain any consistent evidence for the involvement of Ca2+-activation of large conductance calcium-activated potassium (BK) and small conductance calcium-activated potassium (SK) channels in these events. In conclusion, the reduced Ca2+ elevation as a result of single AP stimulation is likely to result from the reduced duration of the AP in α2δ-1 knockout sensory neurons. This article is part of the themed issue ‘Evolution brings Ca2+ and ATP together to control life and death’. PMID:27377724

  6. [Mirror neurons]. (United States)

    Rubia Vila, Francisco José


    Mirror neurons were recently discovered in frontal brain areas of the monkey. They are activated when the animal makes a specific movement, but also when the animal observes the same movement in another animal. Some of them also respond to the emotional expression of other animals of the same species. These mirror neurons have also been found in humans. They respond to or "reflect" actions of other individuals in the brain and are thought to represent the basis for imitation and empathy and hence the neurobiological substrate for "theory of mind", the potential origin of language and the so-called moral instinct.

  7. Eugenol and carvacrol excite first- and second-order trigeminal neurons and enhance their heat-evoked responses. (United States)

    Klein, A H; Joe, C L; Davoodi, A; Takechi, K; Carstens, M I; Carstens, E


    Eugenol and carvacrol from clove and oregano, respectively, are agonists of the warmth-sensitive transient receptor potential channel TRPV3 and the irritant-sensitive transient receptor potential ankyrin (TRPA)-1. Eugenol and carvacrol induce oral irritation that rapidly desensitizes, accompanied by brief enhancement of innocuous warmth and heat pain in humans. We presently investigated if eugenol and carvacrol activate nociceptive primary afferent and higher order trigeminal neurons and enhance their heat-evoked responses, using calcium imaging of cultured trigeminal ganglion (TG) and dorsal root ganglion (DRG) neurons, and in vivo single-unit recordings in trigeminal subnucleus caudalis (Vc) of rats. Eugenol and carvacrol activated 20-30% of TG and 7-20% of DRG cells, the majority of which additionally responded to menthol, mustard oil and/or capsaicin. TG cell responses to innocuous (39°) and noxious (42 °C) heating were enhanced by eugenol and carvacrol. We identified dorsomedial Vc neurons responsive to noxious heating of the tongue in pentobarbital-anesthetized rats. Eugenol and carvacrol dose-dependently elicited desensitizing responses in 55% and 73% of heat-sensitive units, respectively. Responses to noxious heat were briefly enhanced by eugenol and carvacrol. Many eugenol- and carvacrol-responsive units also responded to menthol, cinnamaldehyde and capsaicin. These data support a peripheral site for eugenol and carvacrol to enhance warmth- and noxious heat-evoked responses of trigeminal neurons, and are consistent with the observation that these agonists briefly enhance warmth and heat pain on the human tongue.

  8. TRPM8 and Nav1.8 sodium channels are required for transthyretin-induced calcium influx in growth cones of small-diameter TrkA-positive sensory neurons

    Directory of Open Access Journals (Sweden)

    Vincent Adele J


    Full Text Available Abstract Background Familial amyloidotic polyneuropathy (FAP is a peripheral neuropathy caused by the extracellular accumulation and deposition of insoluble transthyretin (TTR aggregates. However the molecular mechanism that underlies TTR toxicity in peripheral nerves is unclear. Previous studies have suggested that amyloidogenic proteins can aggregate into oligomers which disrupt intracellular calcium homeostasis by increasing the permeability of the plasma membrane to extracellular calcium. The aim of the present study was to examine the effect of TTR on calcium influx in dorsal root ganglion neurons. Results Levels of intracellular cytosolic calcium were monitored in dorsal root ganglion (DRG neurons isolated from embryonic rats using the calcium-sensitive fluorescent indicator Fluo4. An amyloidogenic mutant form of TTR, L55P, induced calcium influx into the growth cones of DRG neurons, whereas wild-type TTR had no significant effect. Atomic force microscopy and dynamic light scattering studies confirmed that the L55P TTR contained oligomeric species of TTR. The effect of L55P TTR was decreased by blockers of voltage-gated calcium channels (VGCC, as well as by blockers of Nav1.8 voltage-gated sodium channels and transient receptor potential M8 (TRPM8 channels. siRNA knockdown of TRPM8 channels using three different TRPM8 siRNAs strongly inhibited calcium influx in DRG growth cones. Conclusions These data suggest that activation of TRPM8 channels triggers the activation of Nav1.8 channels which leads to calcium influx through VGCC. We suggest that TTR-induced calcium influx into DRG neurons may contribute to the pathophysiology of FAP. Furthermore, we speculate that similar mechanisms may mediate the toxic effects of other amyloidogenic proteins such as the β-amyloid protein of Alzheimer's disease.

  9. Nitric oxide activates ATP-sensitive potassium channels in mammalian sensory neurons: action by direct S-nitrosylation

    Directory of Open Access Journals (Sweden)

    Kwok Wai-Meng


    Full Text Available Abstract Background ATP-sensitive potassium (KATP channels in neurons regulate excitability, neurotransmitter release and mediate protection from cell-death. Furthermore, activation of KATP channels is suppressed in DRG neurons after painful-like nerve injury. NO-dependent mechanisms modulate both KATP channels and participate in the pathophysiology and pharmacology of neuropathic pain. Therefore, we investigated NO modulation of KATP channels in control and axotomized DRG neurons. Results Cell-attached and cell-free recordings of KATP currents in large DRG neurons from control rats (sham surgery, SS revealed activation of KATP channels by NO exogenously released by the NO donor SNAP, through decreased sensitivity to [ATP]i. This NO-induced KATP channel activation was not altered in ganglia from animals that demonstrated sustained hyperalgesia-type response to nociceptive stimulation following spinal nerve ligation. However, baseline opening of KATP channels and their activation induced by metabolic inhibition was suppressed by axotomy. Failure to block the NO-mediated amplification of KATP currents with specific inhibitors of sGC and PKG indicated that the classical sGC/cGMP/PKG signaling pathway was not involved in the activation by SNAP. NO-induced activation of KATP channels remained intact in cell-free patches, was reversed by DTT, a thiol-reducing agent, and prevented by NEM, a thiol-alkylating agent. Other findings indicated that the mechanisms by which NO activates KATP channels involve direct S-nitrosylation of cysteine residues in the SUR1 subunit. Specifically, current through recombinant wild-type SUR1/Kir6.2 channels expressed in COS7 cells was activated by NO, but channels formed only from truncated isoform Kir6.2 subunits without SUR1 subunits were insensitive to NO. Further, mutagenesis of SUR1 indicated that NO-induced KATP channel activation involves interaction of NO with residues in the NBD1 of the SUR1 subunit. Conclusion NO

  10. Neuronal plasticity in chronic pancreatitis is mediated via the neurturin/GFRα2 axis. (United States)

    Demir, Ihsan Ekin; Wang, Kun; Tieftrunk, Elke; Giese, Nathalia A; Xing, Baocai; Friess, Helmut; Kehl, Timo; Ceyhan, Güralp O


    The glial cell line-derived neurotrophic factor (GDNF) family member neurturin (NRTN) and its receptor GFRα2 play a deciding role in the normal development of pancreatic parasympathetic innervation. In this study, we aimed at investigating the role of NRTN/GFRα2 axis in pancreatic neuropathy in human chronic pancreatitis (CP). Expression of NRTN/GFRα2 was compared between normal human pancreas (NP) and CP tissues via immunohistochemistry, immunoblotting, and quantitative RT-PCR and correlated to abdominal pain sensation. To elucidate the impact of NRTN in pancreatic neuroplasticity, neuronal phenotype and glial density were quantified via an in vitro neuroplasticity assay in dissociated newborn rat dorsal root ganglia (DRG) cultured 1) in CP tissue extracts depleted from NRTN, 2) in NP, 3) in untreated CP tissue extracts, and 4) CP extracts in which nerve growth factor, glial cell derived-neurotrophic factor, or TGF-β(1) was depleted. NRTN and GFRα2 were highly upregulated in CP, especially in intrapancreatic nerves and the extracellular matrix. CP tissue demonstrated increased amounts of mature multimeric NRTN and elevated levels of GFRα2. The noticeable neurotrophic effect of CP tissue extracts on DRG neurons was diminished upon blockade of NRTN from these extracts. However, blockade of NRTN from CP extracts did not influence the density of DRG glia cells. In conclusion, the NRTN/GFRα2 axis is activated during the course of CP and represents a major key player in the reactive neural alterations in CP. This is the first study to provide functional evidence for the contribution of neurotrophic factors to neuroplasticity in CP.

  11. Valutazione dell'appropriatezza dei ricoveri in un Policlinico Universitario: analisi mediante l'uso comparativo dei sistemi di classificazione isogravitá APR-DRG e Disease Staging e del PRUO

    Directory of Open Access Journals (Sweden)

    M. Volpe


    Full Text Available

    Obiettivi: valutare l’appropriatezza organizzativa dei ricoveri effettuati in un Policlinico Universitario attraverso la comparazione di due metodi, dei quali uno basato sui dati della scheda di dimissione ospedaliera ed utilizza, rispettivamente, i sistemi di classificazione iso-gravità APR-DRG e Disease Staging e l’altro sulla revisione delle cartelle cliniche mediante il PRUO.

    Metodi: oggetto di analisi sono i ricoveri ordinari effettuati nell’anno 2001 ed afferenti ai DRG inclusi nella delibera della Giunta Regionale del Lazio 864/2002 che recepisce il D.P.C.M. 29/11/2001 sui livelli essenziali di assistenza.

    Risultati: i risultati evidenziano che le due varianti del
    metodo basato sulla SDO (metodo APPRO mostrano quote di ricoveri inappropriati sovrapponibili rispetto al complesso dei ricoveri oggetto di analisi, ma con differenze anche rilevanti tra APR-DRG e Disease Staging in relazione ai singoli DRG considerati, riconducibili ai diversi algoritmi di attribuzione del livello di severità utilizzati dai due sistemi. L’analisi campionaria effettuata con il metodo PRUO su casi afferenti ai DRG della DGR 864/2002 caratterizzati da livelli di severità minimi evidenzia una proporzione di ricoveri inappropriati superiore a quella determinata tramite i metodi basati sulla SDO. Tale differenza è verosimilmente dovuta al ruolo del valore delle soglie percentuali di accettabilità individuate dalla Regione Lazio per ciascun DRG: le quote di ricoveri che eccedono tali soglie sono considerate inappropriate.

    Conclusioni: sulla base dei risultati ottenuti gli autori
    descrivono gli interventi organizzativi adottati per ottimizzare il contesto di erogazione delle prestazioni
    oggetto di analisi, discutono vantaggi e limiti dei metodi SDO-based e del metodo analitico PRUObased e ne propongono l

  12. A simple, highly efficient method for heterologous expression in mammalian primary neurons using cationic lipid-mediated mRNA transfection

    Directory of Open Access Journals (Sweden)

    Damian J Williams


    Full Text Available Expression of heterologous proteins in adult mammalian neurons is a valuable technique for the study of neuronal function. The postmitotic nature of mature neurons prevents effective DNA transfection using simple, cationic lipid-based methods. Adequate heterologous protein expression is often only achievable using complex techniques that, in many cases, are associated with substantial toxicity. Here, a simple method for high efficiency transfection of mammalian primary neurons using in vitro-transcribed mRNA and the cationic lipid transfection reagent Lipofectamine 2000 is described. Optimal transfection conditions were established in adult mouse dissociated dorsal root ganglion (DRG neurons using a 96-well based luciferase activity assay. Using these conditions, a transfection efficiency of 25% was achieved in DRG neurons transfected with EGFP mRNA. High transfection efficiencies were also obtained in dissociated rat superior cervical ganglion (SCG neurons and mouse cortical and hippocampal cultures. Endogenous Ca2+ currents in EGFP mRNA-transfected SCG neurons were not significantly different from untransfected neurons, which suggested that this technique is well suited for heterologous expression in patch clamp recording experiments. Functional expression of a cannabinoid receptor (CB1R, a G protein inwardly-rectifying K+ channel (GIRK4 and a dominant-negative G protein α-subunit mutant (GoA G203T indicate that the levels of heterologous protein expression attainable using mRNA transfection are suitable for most functional protein studies. This study demonstrates that mRNA transfection is a straightforward and effective method for heterologous expression in neurons and is likely to have many applications in neuroscience research.

  13. Ligustrazine inhibits high voltage-gated Ca2+ and TTX-resistant Na+ channels of primary sensory neuron and thermal nociception in the rat:a study on peripheral mechanism

    Institute of Scientific and Technical Information of China (English)


    Objective Ligustrazine, also named as tetramethylpyrazine, is a compound purified from Ligusticum chuanxiong hort and has ever been testified to be a calcium antagonist. The present investigation was to determine the antinociceptive effect of ligustrazine and, if any, the peripheral ionic mechanism involved. Methods Paw withdrawal Latency(PWL) to noxious heating was measured in vivo and whole-cell patch recording was performed on small dorsal root ganglion (DRG) neurons. Results Intraplantar injection of ligustrazine (0.5 mg in 25 μl) significantly prolonged the withdrawal latency of ipsilateral hindpaw to noxious heating in the rat. Ligustrazine not only reversibly inhibited high-voltage gated calcium current of dorsal root ganglion (DRG) neuron in dose-dependent manner with IC50 of 1.89 mmol/L, but also decreased tetrodotoxin (TTX) -resistant sodium current in relatively selective and dose-dependent manner with IC50 of2.49 mmol/L. Conclusion The results suggested that ligustrazine could elevate the threshold of thermal nociception through inhibiting the high-voltage gated calcium current and TTX-resistant sodium current of DRG neuron .in the rat.

  14. Evaluation of the synuclein-γ (SNCG gene as a PPARγ target in murine adipocytes, dorsal root ganglia somatosensory neurons, and human adipose tissue.

    Directory of Open Access Journals (Sweden)

    Tamara N Dunn

    Full Text Available Recent evidence in adipocytes points to a role for synuclein-γ in metabolism and lipid droplet dynamics, but interestingly this factor is also robustly expressed in peripheral neurons. Specific regulation of the synuclein-γ gene (Sncg by PPARγ requires further evaluation, especially in peripheral neurons, prompting us to test if Sncg is a bona fide PPARγ target in murine adipocytes and peripheral somatosensory neurons derived from the dorsal root ganglia (DRG. Sncg mRNA was decreased in 3T3-L1 adipocytes (~68% by rosiglitazone, and this effect was diminished by the PPARγ antagonist T0070907. Chromatin immunoprecipitation experiments confirmed PPARγ protein binding at two promoter sequences of Sncg during 3T3-L1 adipogenesis. Rosiglitazone did not affect Sncg mRNA expression in murine cultured DRG neurons. In subcutaneous human WAT samples from two cohorts treated with pioglitazone (>11 wks, SNCG mRNA expression was reduced, albeit highly variable and most evident in type 2 diabetes. Leptin (Lep expression, thought to be coordinately-regulated with Sncg based on correlations in human adipose tissue, was also reduced in 3T3-L1 adipocytes by rosiglitazone. However, Lep was unaffected by PPARγ antagonist, and the LXR agonist T0901317 significantly reduced Lep expression (~64% while not impacting Sncg. The results support the concept that synuclein-γ shares some, but not all, gene regulators with leptin and is a PPARγ target in adipocytes but not DRG neurons. Regulation of synuclein-γ by cues such as PPARγ agonism in adipocytes is logical based on recent evidence for an important role for synuclein-γ in the maintenance and dynamics of adipocyte lipid droplets.

  15. Acute p38-mediated modulation of tetrodotoxin-resistant sodium channels in mouse sensory neurons by tumor necrosis factor-alpha. (United States)

    Jin, Xiaochun; Gereau, Robert W


    Tumor necrosis factor-alpha (TNFalpha) is a proinflammatory cytokine involved in the development and maintenance of inflammatory and neuropathic pain conditions. TNFalpha can have long-lasting effects by regulating the expression of a variety of inflammatory mediators, including other cytokines and TNFalpha itself. However, the speed with which TNFalpha induces tactile and thermal hypersensitivity suggests that transcriptional regulation cannot fully account for its sensitizing effects, and some recent findings suggest that TNFalpha may act directly on primary afferent neurons to induce pain hypersensitivity. In the present study, we show that peripheral administration of TNFalpha induces thermal hypersensitivity in wild-type mice but not in transient receptor potential vanilloid receptor TRPV1(-/-) mice. In contrast, TNFalpha produced equivalent mechanical hypersensitivity in TRPV1(-/-) mice and wild-type littermates, suggesting a role for TRPV1 in TNFalpha-induced thermal, but not mechanical, hypersensitivity. Because tetrodotoxin (TTX)-resistant Na+ channels are a critical site of modulation underlying mechanical hypersensitivity in inflammatory and neuropathic pain conditions, we tested the effects of TNFalpha on these channels in isolated mouse dorsal root ganglion (DRG) neurons. We report that acute application of TNFalpha rapidly enhances TTX-resistant Na+ currents in isolated DRG neurons. This potentiation of TTX-resistant currents by TNFalpha is dramatically reduced in DRG neurons from TNF receptor 1 (TNFR1) knock-out mice and is blocked by the p38 mitogen-activated protein kinase inhibitor SB202190 [4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)1H-imidazole]. Mechanical hypersensitivity induced by peripherally applied TNFalpha is also significantly reduced by SB202190. These results suggest that TNFalpha may induce acute peripheral mechanical sensitization by acting directly on TNFR1 in primary afferent neurons, resulting in p38-dependent modulation

  16. Characterization of thoracic motor and sensory neurons and spinal nerve roots in canine degenerative myelopathy, a potential disease model of amyotrophic lateral sclerosis. (United States)

    Morgan, Brandie R; Coates, Joan R; Johnson, Gayle C; Shelton, G Diane; Katz, Martin L


    Canine degenerative myelopathy (DM) is a progressive, adult-onset, multisystem degenerative disease with many features in common with amyotrophic lateral sclerosis (ALS). As with some forms of ALS, DM is associated with mutations in superoxide dismutase 1 (SOD1). Clinical signs include general proprioceptive ataxia and spastic upper motor neuron paresis in pelvic limbs, which progress to flaccid tetraplegia and dysphagia. The purpose of this study was to characterize DM as a potential disease model for ALS. We previously reported that intercostal muscle atrophy develops in dogs with advanced-stage DM. To determine whether other components of the thoracic motor unit (MU) also demonstrated morphological changes consistent with dysfunction, histopathologic and morphometric analyses were conducted on thoracic spinal motor neurons (MNs) and dorsal root ganglia (DRG) and in motor and sensory nerve root axons from DM-affected boxers and Pembroke Welsh corgis (PWCs). No alterations in MNs or motor root axons were observed in either breed. However, advanced-stage PWCs exhibited significant losses of sensory root axons, and numerous DRG sensory neurons displayed evidence of degeneration. These results indicate that intercostal muscle atrophy in DM is not preceded by physical loss of the motor neurons innervating these muscles, nor of their axons. Axonal loss in thoracic sensory roots and sensory neuron death suggest that sensory involvement may play an important role in DM disease progression. Further analysis of the mechanisms responsible for these morphological findings would aid in the development of therapeutic intervention for DM and some forms of ALS.

  17. Diabetic polyneuropathy, sensory neurons, nuclear structure and spliceosome alterations: a role for CWC22

    Directory of Open Access Journals (Sweden)

    Masaki Kobayashi


    Full Text Available Unique deficits in the function of adult sensory neurons as part of their early neurodegeneration might account for progressive polyneuropathy during chronic diabetes mellitus. Here, we provide structural and functional evidence for aberrant pre-mRNA splicing in a chronic type 1 model of experimental diabetic polyneuropathy (DPN. Cajal bodies (CBs, unique nuclear substructures involved in RNA splicing, increased in number in diabetic sensory neurons, but their expected colocalization with survival motor neuron (SMN proteins was reduced – a mislocalization described in motor neurons of spinal muscular atrophy. Small nuclear ribonucleoprotein particles (snRNPs, also participants in the spliceosome, had abnormal multiple nuclear foci unassociated with CBs, and their associated snRNAs were reduced. CWC22, a key spliceosome protein, was aberrantly upregulated in diabetic dorsal root ganglia (DRG, and impaired neuronal function. CWC22 attenuated sensory neuron plasticity, with knockdown in vitro enhancing their neurite outgrowth. Further, axonal delivery of CWC22 siRNA unilaterally to locally knock down the aberrant protein in diabetic nerves improved aspects of sensory function in diabetic mice. Collectively, our findings identify subtle but significant alterations in spliceosome structure and function, including dysregulated CBs and CWC22 overexpression, in diabetic sensory neurons that offer new ideas regarding diabetic sensory neurodegeneration in polyneuropathy.

  18. Diabetic polyneuropathy, sensory neurons, nuclear structure and spliceosome alterations: a role for CWC22 (United States)

    Kobayashi, Masaki; Chandrasekhar, Ambika; Cheng, Chu; Martinez, Jose A.; Ng, Hilarie; de la Hoz, Cristiane


    ABSTRACT Unique deficits in the function of adult sensory neurons as part of their early neurodegeneration might account for progressive polyneuropathy during chronic diabetes mellitus. Here, we provide structural and functional evidence for aberrant pre-mRNA splicing in a chronic type 1 model of experimental diabetic polyneuropathy (DPN). Cajal bodies (CBs), unique nuclear substructures involved in RNA splicing, increased in number in diabetic sensory neurons, but their expected colocalization with survival motor neuron (SMN) proteins was reduced – a mislocalization described in motor neurons of spinal muscular atrophy. Small nuclear ribonucleoprotein particles (snRNPs), also participants in the spliceosome, had abnormal multiple nuclear foci unassociated with CBs, and their associated snRNAs were reduced. CWC22, a key spliceosome protein, was aberrantly upregulated in diabetic dorsal root ganglia (DRG), and impaired neuronal function. CWC22 attenuated sensory neuron plasticity, with knockdown in vitro enhancing their neurite outgrowth. Further, axonal delivery of CWC22 siRNA unilaterally to locally knock down the aberrant protein in diabetic nerves improved aspects of sensory function in diabetic mice. Collectively, our findings identify subtle but significant alterations in spliceosome structure and function, including dysregulated CBs and CWC22 overexpression, in diabetic sensory neurons that offer new ideas regarding diabetic sensory neurodegeneration in polyneuropathy. PMID:28250049

  19. Diabetic polyneuropathy, sensory neurons, nuclear structure and spliceosome alterations: a role for CWC22. (United States)

    Kobayashi, Masaki; Chandrasekhar, Ambika; Cheng, Chu; Martinez, Jose A; Ng, Hilarie; de la Hoz, Cristiane; Zochodne, Douglas W


    Unique deficits in the function of adult sensory neurons as part of their early neurodegeneration might account for progressive polyneuropathy during chronic diabetes mellitus. Here, we provide structural and functional evidence for aberrant pre-mRNA splicing in a chronic type 1 model of experimental diabetic polyneuropathy (DPN). Cajal bodies (CBs), unique nuclear substructures involved in RNA splicing, increased in number in diabetic sensory neurons, but their expected colocalization with survival motor neuron (SMN) proteins was reduced - a mislocalization described in motor neurons of spinal muscular atrophy. Small nuclear ribonucleoprotein particles (snRNPs), also participants in the spliceosome, had abnormal multiple nuclear foci unassociated with CBs, and their associated snRNAs were reduced. CWC22, a key spliceosome protein, was aberrantly upregulated in diabetic dorsal root ganglia (DRG), and impaired neuronal function. CWC22 attenuated sensory neuron plasticity, with knockdown in vitro enhancing their neurite outgrowth. Further, axonal delivery of CWC22 siRNA unilaterally to locally knock down the aberrant protein in diabetic nerves improved aspects of sensory function in diabetic mice. Collectively, our findings identify subtle but significant alterations in spliceosome structure and function, including dysregulated CBs and CWC22 overexpression, in diabetic sensory neurons that offer new ideas regarding diabetic sensory neurodegeneration in polyneuropathy.

  20. Alterations in the Local Axonal Environment Influence Target Reinnervation and Neuronal Survival After PostnataI Axotomy (United States)


    xvii ANOVA BDNF BSA CN CNS CNTF DAB DAPI DPN DPO DRG E(number) ECM EGF EM FGF bFGF FITC GAL-C GGF HRP Ig IGF-I IGF-II IGFBP-I LARB LM MBP NGF p75NGFR...Unfortunately, experiments employing this technique in combination with axotomy have had limited success. Although brain- derived neurotrophic factor ( BDNF ...neurons in the nuclei of uninjured hypoglossal nerves following HRP injections represent a distinct interneuron population that does not project to the

  1. Comparison of icilin- and cold-evoked responses of spinal neurones, and their modulation of mechanical activity, in a model of neuropathic pain. (United States)

    Brignell, Jennifer L; Chapman, Victoria; Kendall, David A


    Cold allodynia is a poorly understood symptom of neuropathic pain. Two members of the transient receptor potential (TRP) family of proteins, TRPM8 and TRPA1, may contribute to cold somatosensation. The aim of the present study was to investigate the usefulness of icilin as a pharmacological tool to study primary afferent fibre responses to cold stimuli and to determine whether there are differences in the responses of spinal neurones to cooling of peripheral receptive fields in control versus neuropathic rats. The effects of icilin, a TRPM8 and TRPA1 agonist, on intracellular Ca(2+) ([Ca(2+)](i)) responses of small diameter adult dorsal root ganglia (DRG) neurones were determined. Icilin (10 nM-10 microM) produced a concentration-related increase in [Ca(2+)](i) in DRG neurones, which was attenuated by the non-selective TRP channel antagonist ruthenium red (10 microM). In vivo electrophysiology in naïve, sham-operated and SNL rats demonstrated that application of ice to receptive fields evoked firing of wide dynamic range (WDR) neurones, which was significantly greater in SNL rats than naïve and sham-operated rats. Intraplantar injection of icilin did not evoke firing of WDR neurones in naïve, sham-operated or SNL rats but inhibited mechanically-evoked responses of WDR neurones in naïve and sham-operated rats, whilst facilitating mechanically-evoked responses in SNL rats. Icilin increased both innocuous (sham-operated and SNL rats) and noxious (SNL rats) receptive field sizes of WDR neurones. Our data suggests that icilin modulates the mechanosensitivity of dorsal horn neurones. The differing effects of ice and icilin on dorsal horn neurones indicate different mechanisms of action.

  2. Acetylsalicylic acid-induced changes in the chemical coding of extrinsic sensory neurons supplying the prepyloric area of the porcine stomach. (United States)

    Rytel, L; Calka, J


    Acetylsalicylic acid is a popular drug that is commonly used to treat fever and inflammation, but which can also negativity affect the mucosal layer of the stomach, although knowledge concerning its influence on gastric innervation is very scarce. Thus, the aim of the present study was to study the influence of prolonged acetylsalicylic acid supplementation on the extrinsic primary sensory neurons supplying the porcine stomach prepyloric region. Fast Blue (FB) was injected into the above-mentioned region of the stomach. Acetylsalicylic acid was then given orally to the experimental gilts from the seventh day after FB injection to the 27th day of the experiment. After euthanasia, the nodose ganglia (NG) and dorsal root ganglia (DRG) were collected. Sections of these ganglia were processed for routine double-labelling immunofluorescence technique for substance P (SP), calcitonine gene related peptide (CGRP), galanin (GAL), neuronal isoform of nitric oxide synthase (nNOS) and vasoactive intestinal polypeptide (VIP). Under physiological conditions within the nodose ganglia, the percentage of the FB-labeled neurons immunoreactive to particular substances ranged between 17.9 ± 2.7% (VIP-like immunoreactive (LI) neurons in the right NG) and 60.4 ± 1.7% (SP-LI cells within the left NG). Acetylsalicylic acid supplementation caused a considerable increase in the expression of all active substances studied within both left and right NG and the percentage of neurons positive to particular substances fluctuated from 47.2 ± 3.6% (GAL-LI neurons in the right NG) to 67.2 ± 2.0% (cells immunoreactive to SP in the left NG). All studied substances were also observed in DRG neurons supplying the prepyloric region of the stomach, but the number of immunoreactive neurons was too small to conduct a statistical analysis. The obtained results show that ASA may influence chemical coding of the sensory neurons supplying the porcine stomach, but the exact mechanisms of this action still

  3. The Survival Effects of Electeromagnetic Fields on Dorsal Root Ganglia Neurons of the Crushed Sciatic Nerve in the Rat

    Directory of Open Access Journals (Sweden)

    M.R. Nikravesh


    Full Text Available Previous studies have been shown that electromagnetic fields (EMF result in increasing the rate of nerve regeneration. Therefore it could be assumed following axotomy the signal induction of these fields may protect neural cells from death. For this study 24 male wistar rats (2 month age divided to 4 groups (experimental 1, 2, control and sham. For axotomy, the animals were anesthetized and their right Sciatic Nerve (SN were exposed and crushed in the mid portion of the thigh in experimental and control groups. In the sham group the SN just exposed (no compression. In the next phase experimental groups were exposed to the 50 HZ electeromagnetic field (EMF, 1.1mTl 2-4 hr/day (for 10 days. After 8 weeks, Dorsal Root Ganglions (DRGs in the lumbar segments (L4-L6 of spinal cord were sampled, processed sectioned serially and stained with toluidine blue (pH=4.5. By using stereological quantitative technique (physical disector, the neurons in the crushed side (DRGs were counted and compared in the all of groups. Statistical analyses of results have been shown a remarkable reduction in neuronal density in (DRGs of control. On the other hand we observed a cell death DRG significant among experimental groups (p<0/05. In addition we compared DRG volume in all groups but they didn’t show any significant difference. These findings indicate that the EMF may play a survival role against neuronal death during nerve injuries.


    Institute of Scientific and Technical Information of China (English)

    李全波; 马文庭; 刘静芷; 史可梅; 郑宝森


    Objective: To establish a feasible method of culture and purification of newborn dorsal root ganglion neurons of rats. Methods: Sufficient dorsal root ganglions (DRG) were obtained by microdissection, then were dissociated with trypsin and EDTA. The dissociated neurons were cultured with DF-12 media and Cytarabine for purification. NSE staining was used to determine the purification percentage of DRG. Results: The isolated and cultured DRG survived and grew in good condition in vitro, and the purified percentage of DRG was over 90%. Conclusion: The method is very feasible in obtaining the massive highly purified newborn dorsal root ganglion neurons of rats.%目的:建立一种切实可行的新生SD大鼠背根神经节神经元培养及纯化方法.方法:用显微解剖方法获取足够数量新生大鼠背根神经节,通过胰蛋白酶+EDTA消化、交替使用DF-12培养基和加有阿糖胞苷抗有丝分裂的DF-12培养基培养等方法,在体外获得纯化的背根神经节神经元,并采用NSE免疫细胞化学染色方法检测神经元的纯度.结果:获得的背根神经节神经元在体外生长良好,纯度可达到90%以上.结论:本方法可以获得大量高度纯化的大鼠背根神经节神经元.

  5. Induction of complement proteins in a mouse model for cerebral microvascular A beta deposition. (United States)

    Fan, Rong; DeFilippis, Kelly; Van Nostrand, William E


    The deposition of amyloid beta-protein (A beta) in cerebral vasculature, known as cerebral amyloid angiopathy (CAA), is a common pathological feature of Alzheimer's disease and related disorders. In familial forms of CAA single mutations in the A beta peptide have been linked to the increase of vascular A beta deposits accompanied by a strong localized activation of glial cells and elevated expression of neuroinflammatory mediators including complement proteins. We have developed human amyloid-beta precursor protein transgenic mice harboring two CAA A beta mutations (Dutch E693Q and Iowa D694N) that mimic the prevalent cerebral microvascular A beta deposition observed in those patients, and the Swedish mutations (K670N/M671L) to increase A beta production. In these Tg-SwDI mice, we have reported predominant fibrillar A beta along microvessels in the thalamic region and diffuse plaques in cortical region. Concurrently, activated microglia and reactive astrocytes have been detected primarily in association with fibrillar cerebral microvascular A beta in this model. Here we show that three native complement components in classical and alternative complement pathways, C1q, C3, and C4, are elevated in Tg-SwDI mice in regions rich in fibrillar microvascular A beta. Immunohistochemical staining of all three proteins was increased in thalamus, hippocampus, and subiculum, but not frontal cortex. Western blot analysis showed significant increases of all three proteins in the thalamic region (with hippocampus) as well as the cortical region, except C3 that was below detection level in cortex. Also, in the thalamic region (with hippocampus), C1q and C3 mRNAs were significantly up-regulated. These complement proteins appeared to be expressed largely by activated microglial cells associated with the fibrillar microvascular A beta deposits. Our findings demonstrate that Tg-SwDI mice exhibit elevated complement protein expression in response to fibrillar vascular A beta deposition

  6. Mortality experience, 30-days and 365-days after admission, for the 20 most frequent DRG groups among Medicare inpatients aged 65 or older in Connecticut hospitals, fiscal years 1991, 1992, and 1993. (United States)

    Hennen, J; Krumholz, H M; Radford, M J


    This report presents mortality rates following inpatient admissions for the 20 most frequent DRG categories among Medicare inpatients aged > or = 65 years at Connecticut acute-care hospitals during the three-year period from fiscal year 1991 to fiscal year 1993. We provide frequency distributions of the 30-day and 365-day mortality rates among these 20 DRG categories. Among the 199,680 discharges of elderly Medicare beneficiaries within the 20 most frequent DRG categories in the three-year study period, the crude 30-day mortality rate was 9.51%; the crude 365-day mortality rate was 28.40%. By gender, the crude 30-day mortality rate for women was 8.78%; the corresponding rate for men was 10.48%. This gender mortality differential occurred despite a significant age differential; on average, the females were 2.5 years older than the males. By age group, the crude mortality rates were: age 65-74 years, 6.66%; age 75-84 years, 9.80%; age > or = 85 years, 15.25%. The crude mortality rates for the DRG categories were found to be stable over the three-year study period.

  7. DNA polymerase-beta is expressed early in neurons of Alzheimer's disease brain and is loaded into DNA replication forks in neurons challenged with beta-amyloid

    NARCIS (Netherlands)

    A. Copani; J.J.M. Hoozemans; F. Caraci; M. Calafiore; E.S. van Haastert; R. Veerhuis; A.J.M. Rozemuller; E. Aronica; M.A. Sortino; F. Nicoletti


    Cultured neurons exposed to synthetic beta-amyloid (A beta) fragments reenter the cell cycle and initiate a pathway of DNA replication that involves the repair enzyme DNA polymerase-beta (DNA pol-beta) before undergoing apoptotic death. In this study, by performing coimmunoprecipitation experiments

  8. Control of sensory neuron excitability by serotonin involves 5HT2C receptors and Ca(2+)-activated chloride channels. (United States)

    Salzer, Isabella; Gantumur, Enkhbileg; Yousuf, Arsalan; Boehm, Stefan


    Serotonin (5HT) is a constituent of the so-called "inflammatory soup" that sensitizes nociceptors during inflammation. Nevertheless, receptors and signaling mechanisms that mediate an excitation of dorsal root ganglion (DRG) neurons by 5HT remained controversial. Therefore, capsaicin-sensitive nociceptive neurons dissociated from rat DRGs were used to investigate effects of 5HT on membrane excitability and currents through ligand- as well as voltage-gated ion channels. In 58% of the neurons tested, 5HT increased action potential firing, an effect that was abolished by the 5HT2 receptor antagonist ritanserin, but not by the 5HT3 antagonist tropisetron. Unlike other algogenic mediators, such as PGE2 and bradykinin, 5HT did not affect currents through TTX-resistant Na(+) channels or Kv7 K(+) channels. In all neurons investigated, 5HT potentiated capsaicin-evoked currents through TRPV1 channels, an effect that was attenuated by antagonists at 5HT2A (4 F 4 PP), 5HT2B (SB 204741), as well as 5HT2C (RS 102221) receptors. 5HT triggered slowly arising inward Cl(-) currents in 53% of the neurons. This effect was antagonized by the 5HT2C receptor blocker only, and the current was prevented by an inhibitor of Ca(2+)-activated chloride channels (CaCC). The 5HT-induced increase in action potential firing was also abolished by this CaCC blocker and by the TRPV1 inhibitor capsazepine. Amongst the subtype selective 5HT2 antagonists, only RS 102221 (5HT2C-selectively) counteracted the rise in action potential firing elicited by 5HT. These results show that 5HT excites DRG neurons mainly via 5HT2C receptors which concomitantly mediate a sensitization of TRPV1 channels and an opening of CaCCs.

  9. Cannabinoids inhibit acid-sensing ion channel currents in rat dorsal root ganglion neurons.

    Directory of Open Access Journals (Sweden)

    Yu-Qiang Liu

    Full Text Available Local acidosis has been found in various pain-generating conditions such as inflammation and tissue injury. Cannabinoids exert a powerful inhibitory control over pain initiation via peripheral cognate receptors. However, the peripheral molecular targets responsible for the antinociceptive effects of cannabinoids are still poorly understood. Here, we have found that WIN55,212-2, a cannabinoid receptor agonist, inhibits the activity of native acid-sensing ion channels (ASICs in rat dorsal root ganglion (DRG neurons. WIN55,212-2 dose-dependently inhibited proton-gated currents mediated by ASICs. WIN55,212-2 shifted the proton concentration-response curve downwards, with an decrease of 48.6±3.7% in the maximum current response but with no significant change in the EC(50 value. The inhibition of proton-gated current induced by WIN55,212-2 was almost completely blocked by the selective CB1 receptor antagonist AM 281, but not by the CB2 receptor antagonist AM630. Pretreatment of forskolin, an AC activator, and the addition of cAMP also reversed the inhibition of WIN55,212-2. Moreover, WIN55,212-2 altered acid-evoked excitability of rat DRG neurons and decreased the number of action potentials induced by acid stimuli. Finally, WIN55,212-2 attenuated nociceptive responses to injection of acetic acid in rats. These results suggest that WIN55,212-2 inhibits the activity of ASICs via CB1 receptor and cAMP dependent pathway in rat primary sensory neurons. Thus, cannabinoids can exert their analgesic action by interaction with ASICs in the primary afferent neurons, which was novel analgesic mechanism of cannabinoids.

  10. The chemokine CXCL1/growth related oncogene increases sodium currents and neuronal excitability in small diameter sensory neurons

    Directory of Open Access Journals (Sweden)

    Wick Dayna M


    Full Text Available Abstract Background Altered Na+ channel expression, enhanced excitability, and spontaneous activity occur in nerve-injury and inflammatory models of pathological pain, through poorly understood mechanisms. The cytokine GRO/KC (growth related oncogene; CXCL1 shows strong, rapid upregulation in dorsal root ganglion in both nerve injury and inflammatory models. Neurons and glia express its receptor (CXCR2. CXCL1 has well-known effects on immune cells, but little is known about its direct effects on neurons. Results We report that GRO/KC incubation (1.5 nM, overnight caused marked upregulation of Na+ currents in acutely isolated small diameter rat (adult sensory neurons in vitro. In both IB4-positive and IB4-negative sensory neurons, TTX-resistant and TTX-sensitive currents increased 2- to 4 fold, without altered voltage dependence or kinetic changes. These effects required long exposures, and were completely blocked by co-incubation with protein synthesis inhibitor cycloheximide. Amplification of cDNA from the neuronal cultures showed that 3 Na channel isoforms were predominant both before and after GRO/KC treatment (Nav 1.1, 1.7, and 1.8. TTX-sensitive isoforms 1.1 and 1.7 significantly increased 2 – 3 fold after GRO/KC incubation, while 1.8 showed a trend towards increased expression. Current clamp experiments showed that GRO/KC caused a marked increase in excitability, including resting potential depolarization, decreased rheobase, and lower action potential threshold. Neurons acquired a striking ability to fire repetitively; IB4-positive cells also showed marked broadening of action potentials. Immunohistochemical labelling confirmed that the CXCR2 receptor was present in most neurons both in dissociated cells and in DRG sections, as previously shown for neurons in the CNS. Conclusion Many studies on the role of chemokines in pain conditions have focused on their rapid and indirect effects on neurons, via release of inflammatory mediators

  11. R-type calcium channels are crucial for semaphorin 3A-induced DRG axon growth cone collapse.

    Directory of Open Access Journals (Sweden)

    Rimantas Treinys

    Full Text Available Semaphorin 3A (Sema3A is a secreted protein involved in axon path-finding during nervous system development. Calcium signaling plays an important role during axonal growth in response to different guidance cues; however it remains unclear whether this is also the case for Sema3A. In this study we used intracellular calcium imaging to figure out whether Sema3A-induced growth cone collapse is a Ca2+ dependent process. Intracellular Ca2+ imaging results using Fura-2 AM showed Ca2+ increase in E15 mice dorsal root ganglia neurons upon Sema3A treatment. Consequently we analyzed Sema3A effect on growth cones after blocking or modifying intracellular and extracellular Ca2+ channels that are expressed in E15 mouse embryos. Our results demonstrate that Sema3A increased growth cone collapse rate is blocked by the non-selective R- and T- type Ca2+ channel blocker NiCl2 and by the selective R-type Ca2+ channel blocker SNX482. These Ca2+ channel blockers consistently decreased the Sema3A-induced intracellular Ca2+ concentration elevation. Overall, our results demonstrate that Sema3A-induced growth cone collapses are intimately related with increase in intracellular calcium concentration mediated by R-type calcium channels.

  12. Expression of Semaphorins, Neuropilins, VEGF, and Tenascins in Rat and Human Primary Sensory Neurons after a Dorsal Root Injury (United States)

    Lindholm, Tomas; Risling, Mårten; Carlstedt, Thomas; Hammarberg, Henrik; Wallquist, Wilhelm; Cullheim, Staffan; Sköld, Mattias K.


    Dorsal root injury is a situation not expected to be followed by a strong regenerative growth, or growth of the injured axon into the central nervous system of the spinal cord, if the central axon of the dorsal root is injured but of strong regeneration if subjected to injury to the peripherally projecting axons. The clinical consequence of axonal injury is loss of sensation and may also lead to neuropathic pain. In this study, we have used in situ hybridization to examine the distribution of mRNAs for the neural guidance molecules semaphorin 3A (SEMA3A), semaphorin 3F (SEMA3F), and semaphorin 4F (SEMA4F), their receptors neuropilin 1 (NP1) and neuropilin 2 (NP2) but also for the neuropilin ligand vascular endothelial growth factor (VEGF) and Tenascin J1, an extracellular matrix molecule involved in axonal guidance, in rat dorsal root ganglia (DRG) after a unilateral dorsal rhizotomy (DRT) or sciatic nerve transcetion (SNT). The studied survival times were 1–365 days. The different forms of mRNAs were unevenly distributed between the different size classes of sensory nerve cells. The results show that mRNA for SEMA3A was diminished after trauma to the sensory nerve roots in rats. The SEMA3A receptor NP1, and SEMA3F receptor NP2, was significantly upregulated in the DRG neurons after DRT and SNT. SEMA4F was upregulated after a SNT. The expression of mRNA for VEGF in DRG neurons after DRT showed a significant upregulation that was high even a year after the injuries. These data suggest a role for the semaphorins, neuropilins, VEGF, and J1 in the reactions after dorsal root lesions. PMID:28270793

  13. Identification of distinct physiochemical properties of toxic prefibrillar species formed by A{beta} peptide variants

    Energy Technology Data Exchange (ETDEWEB)

    Goeransson, Anna-Lena, E-mail: [Division of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linkoeping University (Sweden); Nilsson, K. Peter R., E-mail: [Division of Organic Chemistry, Department of Physics, Chemistry and Biology, Linkoeping University (Sweden); Kagedal, Katarina, E-mail: [Department of Clinical and Experimental Medicine, Linkoeping University (Sweden); Brorsson, Ann-Christin, E-mail: [Division of Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linkoeping University (Sweden)


    Highlights: Black-Right-Pointing-Pointer Identification of toxic prefibrillar A{beta} species. Black-Right-Pointing-Pointer Fluorescence measurements using a combined set of fluorophores. Black-Right-Pointing-Pointer Morphology studies using transmission electron microscopy. -- Abstract: The formation of amyloid-{beta} peptide (A{beta}) aggregates at an early stage during the self-assembly process is an important factor in the development of Alzheimer's disease. The toxic effect is believed to be exerted by prefibrillar species of A{beta}. It is therefore important to identify which prefibrillar species are toxic and characterize their distinct properties. In the present study, we investigated the in vitro aggregation behavior of A{beta}-derived peptides possessing different levels of neurotoxic activity, using fluorescence spectroscopy in combination with transmission electron microscopy. The toxicity of various A{beta} aggregates was assessed by using cultures of human neuroblastoma cells. Through combined use of the fluorescence probe 8-anilino-1-napthalenesulfonate (ANS) and the novel luminescent probe pentamer formyl thiophene acetic acid (p-FTAA), we were able to identify those A{beta} peptide-derived prefibrillar species which exhibited cellular toxicity. In particular, species, which formed early during the aggregation process and showed strong p-FTAA and ANS fluorescence, were the species that possessed toxic activities. Moreover, by manipulating the aggregation conditions, it was possible to change the capacity of the A{beta} peptide to form nontoxic versus toxic species.

  14. [Neuronal network]. (United States)

    Langmeier, M; Maresová, D


    Function of the central nervous system is based on mutual relations among the nerve cells. Description of nerve cells and their processes, including their contacts was enabled by improvement of optical features of the microscope and by the development of impregnation techniques. It is associated with the name of Antoni van Leeuwenhoek (1632-1723), J. Ev. Purkyne (1787-1869), Camillo Golgi (1843-1926), and Ramón y Cajal (1852-1934). Principal units of the neuronal network are the synapses. The term synapse was introduced into neurophysiology by Charles Scott Sherrington (1857-1952). Majority of the interactions between nerve cells is mediated by neurotransmitters acting at the receptors of the postsynaptic membrane or at the autoreceptors of the presynaptic part of the synapse. Attachment of the vesicles to the presynaptic membrane and the release of the neurotransmitter into the synaptic cleft depend on the intracellular calcium concentration and on the presence of several proteins in the presynaptic element.

  15. IL-33/ST2 signaling excites sensory neurons and mediates itch response in a mouse model of poison ivy contact allergy. (United States)

    Liu, Boyi; Tai, Yan; Achanta, Satyanarayana; Kaelberer, Melanie M; Caceres, Ana I; Shao, Xiaomei; Fang, Jianqiao; Jordt, Sven-Eric


    Poison ivy-induced allergic contact dermatitis (ACD) is the most common environmental allergic condition in the United States. Case numbers of poison ivy ACD are increasing due to growing biomass and geographical expansion of poison ivy and increasing content of the allergen, urushiol, likely attributable to rising atmospheric CO2 Severe and treatment-resistant itch is the major complaint of affected patients. However, because of limited clinical data and poorly characterized models, the pruritic mechanisms in poison ivy ACD remain unknown. Here, we aim to identify the mechanisms of itch in a mouse model of poison ivy ACD by transcriptomics, neuronal imaging, and behavioral analysis. Using transcriptome microarray analysis, we identified IL-33 as a key cytokine up-regulated in the inflamed skin of urushiol-challenged mice. We further found that the IL-33 receptor, ST2, is expressed in small to medium-sized dorsal root ganglion (DRG) neurons, including neurons that innervate the skin. IL-33 induces Ca(2+) influx into a subset of DRG neurons through neuronal ST2. Neutralizing antibodies against IL-33 or ST2 reduced scratching behavior and skin inflammation in urushiol-challenged mice. Injection of IL-33 into urushiol-challenged skin rapidly exacerbated itch-related scratching via ST2, in a histamine-independent manner. Targeted silencing of neuronal ST2 expression by intrathecal ST2 siRNA delivery significantly attenuated pruritic responses caused by urushiol-induced ACD. These results indicate that IL-33/ST2 signaling is functionally present in primary sensory neurons and contributes to pruritus in poison ivy ACD. Blocking IL-33/ST2 signaling may represent a therapeutic approach to ameliorate itch and skin inflammation related to poison ivy ACD.

  16. Neural Progenitor Cells Promote Axonal Growth and Alter Axonal mRNA Localization in Adult Neurons (United States)

    Merianda, Tanuja T.; Jin, Ying


    Abstract The inhibitory environment of the spinal cord and the intrinsic properties of neurons prevent regeneration of axons following CNS injury. However, both ascending and descending axons of the injured spinal cord have been shown to regenerate into grafts of embryonic neural progenitor cells (NPCs). Previous studies have shown that grafts composed of glial-restricted progenitors (GRPs) and neural-restricted progenitors (NRPs) can provide a permissive microenvironment for axon growth. We have used cocultures of adult rat dorsal root ganglion (DRG) neurons together with NPCs, which have shown significant enhancement of axon growth by embryonic rat GRP and GRPs/NRPs, both in coculture conditions and when DRGs are exposed to conditioned medium from the NPC cultures. This growth-promoting effect of NPC-conditioned medium was also seen in injury-conditioned neurons. DRGs cocultured with GRPs/NRPs showed altered expression of regeneration-associated genes at transcriptional and post-transcriptional levels. We found that levels of GAP-43 mRNA increased in DRG cell bodies and axons. However, hepcidin antimicrobial peptide (HAMP) mRNA decreased in the cell bodies of DRGs cocultured with GRPs/NRPs, which is distinct from the increase in cell body HAMP mRNA levels seen in DRGs after injury conditioning. Endogenous GAP-43 and β-actin mRNAs as well as reporter RNAs carrying axonally localizing 3'UTRs of these transcripts showed significantly increased levels in distal axons in the DRGs cocultured with GRPs/NRPs. These results indicate that axon growth promoted by NPCs is associated not only with enhanced transcription of growth-associated genes but also can increase localization of some mRNAs into growing axons. PMID:28197547

  17. Complement activation by the amyloid proteins A beta peptide and beta 2-microglobulin

    DEFF Research Database (Denmark)

    Nybo, Mads; Nielsen, E H; Svehag, S E


    Complement activation (CA) has been reported to play a role in the pathogenesis of Alzheimer's disease (AD). To investigate whether CA may contribute to amyloidogenesis in general, the CA potential of different amyloid fibril proteins was tested. CA induced by A beta preparations containing soluble...... protein, protofilaments and some fibrils or only fibrils in a solid phase system (ELISA) was modest with a slow kinetics compared to the positive delta IgG control. Soluble A beta induced no detectable CA in a liquid phase system (complement consumption assay) while fibrillar A beta caused CA at 200 mg....../ml and higher concentrations. Soluble beta 2-microglobulin (beta 2M) purified from peritoneal dialysates was found to be as potent a complement activator as A beta in both solid and liquid phase systems while beta 2M purified from urine exhibited lower activity, a difference which may be explained...

  18. Changes in skin levels of two neutotrophins (glial cell line derived neurotrohic factor and neurotrophin-3) cause alterations in cutaneous neuron responses to mechanical stimuli

    Institute of Scientific and Technical Information of China (English)

    Jeffrey Lawson; Sabrina L. Mcllwrath; H. Richard Koerber


    Neurotrophins are important for the development and maintenance of both high and low threshold mechanoreceptors (HTMRs and LTMRs). In this series of studies, the effects of constitutive overexpression of two different neurotrophins, neurotrophin-3 (NT-3) and glial cell line derived neurotrohic factor (GDNF), were examined. Previous studies indicated that both of them may be implicated in the normal development of mouse dorsal root ganglion (DRG) neurons. Neurons from mice transgenically altered to overexpress NT-3 or GDNF (NT-3-OE or GDNF-OE mice) in the skin were examined using several physiological, immunohistochemi-cal and molecular techniques. Ex vivo skin/nerve/DRG/spinal cord and skin/nerve preparations were used to determine the response characteristics of the cutaneous neurons; immunohistochemistry was used to examine the biochemical phenotype of DRG cells and the skin; RT-PCR was used to examine the levels of candidate ion channels in skin and DRG that may correlate with changes in physiologi-cal responses. In GDNF-OE mice, I-isolectin B4 (IB4)-immunopositive C-HTMRs (nociceptors), a large percentage of which are sensitive to GDNF, had significantly lower mechanical thresholds than wildtype (WT) neurons. Heat thresholds for the same cells were not different. Mechanical sensitivity changes in GDNF-OE mice were correlated with significant increases in acid sensing ion channels 2a (ASIC2a) and 2b (ASIC2b) and transient receptor potential channel AI (TRPAI), all of which are putative mechanosensitive ion channels. Overexpression of NT-3 affected the responses of A-LTMRs and A-HTMRs, hut had no effect on C-HTMRs. Slowly adapting type 1 (SA1) LTMRs and A-HTMRs had increased mechanical sensitivity compared to WT. Mechanical sensitivity was correlated with significant increases in acid-sensing ion channels ASIC1 and ASIC3. This data indicates that both neurotrophins play roles in determining mechanical thresholds of cutaneous HTMRs and LTMRs and that sensitivity

  19. Deletion of ENTPD3 does not impair nucleotide hydrolysis in primary somatosensory neurons or spinal cord [v1; ref status: indexed,

    Directory of Open Access Journals (Sweden)

    Eric McCoy


    Full Text Available Ectonucleotidases are membrane-bound or secreted proteins that hydrolyze extracellular nucleotides.  Recently, we identified three ectonucleotidases that hydrolyze extracellular adenosine 5’-monophosphate (AMP to adenosine in primary somatosensory neurons.  Currently, it is unclear which ectonucleotidases hydrolyze ATP and ADP in these neurons.  Ectonucleoside triphosphate diphosphohydrolases (ENTPDs comprise a class of enzymes that dephosphorylate extracellular ATP and ADP.  Here, we found that ENTPD3 (also known as NTPDase3 or CD39L3 was located in nociceptive and non-nociceptive neurons of the dorsal root ganglion (DRG, in the dorsal horn of the spinal cord, and in free nerve endings in the skin.  To determine if ENTPD3 contributes directly to ATP and ADP hydrolysis in these tissues, we generated and characterized an Entpd3 knockout mouse.  This mouse lacks ENTPD3 protein in all tissues examined, including the DRG, spinal cord, skin, and bladder.  However, DRG and spinal cord tissues from Entpd3-/- mice showed no reduction in histochemical staining when ATP, ADP, AMP, or UTP were used as substrates.  Additionally, using fast-scan cyclic voltammetry (FSCV, adenosine production was not impaired in the dorsal spinal cord of Entpd3-/- mice when the substrate ADP was applied.  Further, Entpd3-/- mice did not differ in nociceptive behaviors when compared to wild-type mice, although Entpd3-/- mice showed a modest reduction in β-alanine-mediated itch.  Taken together, our data indicate that deletion of Entpd3 does not impair ATP or ADP hydrolysis in primary somatosensory neurons or in dorsal spinal cord.  Moreover, our data suggest there could be multiple ectonucleotidases that act redundantly to hydrolyze nucleotides in these regions of the nervous system.

  20. General artificial neuron (United States)

    Degeratu, Vasile; Schiopu, Paul; Degeratu, Stefania


    In this paper the authors present a model of artificial neuron named the general artificial neuron. Depending on application this neuron can change self number of inputs, the type of inputs (from excitatory in inhibitory or vice versa), the synaptic weights, the threshold, the type of intensifying functions. It is achieved into optoelectronic technology. Also, into optoelectronic technology a model of general McCulloch-Pitts neuron is showed. The advantages of these neurons are very high because we have to solve different applications with the same neural network, achieved from these neurons, named general neural network.

  1. Increased function of the TRPV1 channel in small sensory neurons after local inflammation or in vitro exposure to the pro-inflammatory cytokine GRO/KC

    Institute of Scientific and Technical Information of China (English)

    Fei Dong; Yi-Ru Du; Wenrui Xie; Judith A.Strong; Xi-Jing He; Jun-Ming Zhang


    Objective Inflammation at the level of the sensory dorsal root ganglia (DRGs) leads to robust mechanical pain behavior and the local inflammation has direct excitatory effects on sensory neurons including small,primarily nociceptive,neurons.These neurons express the transient receptor potential vanilloid-1 (TRPV 1) channel,which integrates multiple signals of pain and inflammation.The aim of this study was to characterize the regulation of the TRPV1 channel by local DRG inflammation and by growth-related oncogene (GRO/KC,systemic name:CXCL1),a cytokine known to be upregulated in inflamed DRGs.Methods Activation of the TRPV1 receptor with capsaicin was studied with patch clamp methods in acutely isolated small-diameter rat sensory neurons in primary culture.In vivo,behavioral effects of TRPV1 and GRO/KC were examined by paw injections.Results Neurons isolated from lumbar DRGs 3 days after local inflammation showed enhanced TRPV1 function:tachyphylaxis (the decline in response to repeated applications of capsaicin) was significantly reduced.A similar effect on tachyphylaxis was observed in neurons pre-treated for 4 h in vitro with GRO/KC.This effect was blocked by H-89,a protein kinase A inhibitor.Consistent with the in vitro results,in vivo behavioral responses to paw injection of capsaicin were enhanced and prolonged by pre-injecting the paw with GRO/KC 4 h before the capsaicin injection.GRO/KC paw injections alone did not elicit pain behaviors.Conclusion Function of the TRPV 1 channel is enhanced by DRG inflammation and these effects are preserved in vitro during short-term culture.The effects (decreased tachyphylaxis) are mimicked by incubation with GRO/KC,which has previously been found to be strongly upregulated in this and other pain models.

  2. Ciliary neurotrophic factor activates NF-κB to enhance mitochondrial bioenergetics and prevent neuropathy in sensory neurons of streptozotocin-induced diabetic rodents. (United States)

    Saleh, Ali; Roy Chowdhury, Subir K; Smith, Darrell R; Balakrishnan, Savitha; Tessler, Lori; Martens, Corina; Morrow, Dwane; Schartner, Emily; Frizzi, Katie E; Calcutt, Nigel A; Fernyhough, Paul


    Diabetes causes mitochondrial dysfunction in sensory neurons that may contribute to peripheral neuropathy. Ciliary neurotrophic factor (CNTF) promotes sensory neuron survival and axon regeneration and prevents axonal dwindling, nerve conduction deficits and thermal hypoalgesia in diabetic rats. In this study, we tested the hypothesis that CNTF protects sensory neuron function during diabetes through normalization of impaired mitochondrial bioenergetics. In addition, we investigated whether the NF-κB signal transduction pathway was mobilized by CNTF. Neurite outgrowth of sensory neurons derived from streptozotocin (STZ)-induced diabetic rats was reduced compared to neurons from control rats and exposure to CNTF for 24 h enhanced neurite outgrowth. CNTF also activated NF-κB, as assessed by Western blotting for the NF-κB p50 subunit and reporter assays for NF-κB promoter activity. Conversely, blockade of NF-κB signaling using SN50 peptide inhibited CNTF-mediated neurite outgrowth. Studies in mice with STZ-induced diabetes demonstrated that systemic therapy with CNTF prevented functional indices of peripheral neuropathy along with deficiencies in dorsal root ganglion (DRG) NF-κB p50 expression and DNA binding activity. DRG neurons derived from STZ-diabetic mice also exhibited deficiencies in maximal oxygen consumption rate and associated spare respiratory capacity that were corrected by exposure to CNTF for 24 h in an NF-κB-dependent manner. We propose that the ability of CNTF to enhance axon regeneration and protect peripheral nerve from structural and functional indices of diabetic peripheral neuropathy is associated with targeting of mitochondrial function, in part via NF-κB activation, and improvement of cellular bioenergetics.

  3. Endosome-mediated retrograde axonal transport of P2X3 receptor signals in primary sensory neurons

    Institute of Scientific and Technical Information of China (English)

    Xu-Qiao Chen; BinWang; Chengbiao Wu; Jin Pan; Bo Yuan; Yuan-Yuan Su; Xing-Yu Jiang; Xu Zhang; Lan Bao


    Neurotrophins and their receptors adopt signaling endosomes to transmit retrograde signals.However,the mechanisms of retrograde signaling for other ligand/receptor systems are poorly understood.Here,we report that the signals of the purinergic (P)2X3 receptor,an ATP-gated ion channel are retrogradely transported in dorsal root ganglion (DRG) neuron axons.We found that Rab5,a small GTPase,controls the early sorting of P2X3 receptors into endosomes,while Rab7 mediates the fast retrograde transport of P2X3 receptors.Intraplantar injection and axonal application into the microfluidic chamber of α,β-methylene-ATP (α,β-MeATP),a P2X selective agonist,enhanced the endocytosis and retrograde transport of P2X3 receptors.The α,β-MeATP-induced Ca2+ influx activated a pathway comprised of protein kinase C,rat sarcoma viral oncogene and extracellular signal-regulated protein kinase (ERK),which associated with endocytic P2X3 receptors to form signaling endosomes.Disruption of the lipid rafts abolished the α,β-MeATP-induced ERK phosphorylation,endocytosis and retrograde transport of P2X3 receptors.Furthermore,treatment of peripheral axons with α,β-MeATP increased the activation level of ERK and cAMP response element-binding protein in the cell bodies of DRG neurons and enhanced neuronal excitability.Impairment of either microtubule-based axonal transport in vivo or dynein function in vitro blocked α,β-MeATP-induced retrograde signals.These results indicate that P2X3 receptor-activated signals are transmitted via retrogradely transported endosomes in primary sensory neurons and provide a novel signaling mechanism for ligand-gated channels.

  4. The iA{beta}5p {beta}-breaker peptide regulates the A{beta}(25-35) interaction with lipid bilayers through a cholesterol-mediated mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Vitiello, Giuseppe [Department of Chemistry, University of Naples ' Federico II' , Naples (Italy); CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), Florence (Italy); Grimaldi, Manuela; D' Ursi, Anna Maria [Department of Pharmaceutical Science, University of Salerno, Fisciano (Italy); D' Errico, Gerardino, E-mail: [Department of Chemistry, University of Naples ' Federico II' , Naples (Italy); CSGI (Consorzio per lo Sviluppo dei Sistemi a Grande Interfase), Florence (Italy)


    Highlights: Black-Right-Pointing-Pointer iA{beta}5p shows a significant tendency to deeply penetrates the hydrophobic core of lipid membrane. Black-Right-Pointing-Pointer A{beta}(25-35) locates in the external region of the membrane causing a re-positioning of CHOL. Black-Right-Pointing-Pointer iA{beta}5p withholds cholesterol in the inner hydrophobic core of the lipid membrane. Black-Right-Pointing-Pointer iA{beta}5p prevents the A{beta}(25-35) release from the lipid membrane. -- Abstract: Alzheimer's disease is characterized by the deposition of aggregates of the {beta}-amyloid peptide (A{beta}) in the brain. A potential therapeutic strategy for Alzheimer's disease is the use of synthetic {beta}-sheet breaker peptides, which are capable of binding A{beta} but unable to become part of a {beta}-sheet structure, thus inhibiting the peptide aggregation. Many studies suggest that membranes play a key role in the A{beta} aggregation; consequently, it is strategic to investigate the interplay between {beta}-sheet breaker peptides and A{beta} in the presence of lipid bilayers. In this work, we focused on the effect of the {beta}-sheet breaker peptide acetyl-LPFFD-amide, iA{beta}5p, on the interaction of the A{beta}(25-35) fragment with lipid membranes, studied by Electron Spin Resonance spectroscopy, using spin-labeled membrane components (either phospholipids or cholesterol). The ESR results show that iA{beta}5p influences the A{beta}(25-35) interaction with the bilayer through a cholesterol-mediated mechanism: iA{beta}5p withholds cholesterol in the inner hydrophobic core of the bilayer, making the interfacial region more fluid and capable to accommodate A{beta}(25-35). As a consequence, iA{beta}5p prevents the A{beta}(25-35) release from the lipid membrane, which is the first step of the {beta}-amyloid aggregation process.

  5. NEURON and Python


    Michael Hines; Davison, Andrew P.; Eilif Muller


    The NEURON simulation program now allows Python to be used, alone or in combination with NEURON's traditional Hoc interpreter. Adding Python to NEURON has the immediate benefit of making available a very extensive suite of analysis tools written for engineering and science. It also catalyzes NEURON software development by offering users a modern programming tool that is recognized for its flexibility and power to create and maintain complex programs. At the same time, nothing is lost because ...

  6. CCL2 Mediates Neuron-Macrophage Interactions to Drive Proregenerative Macrophage Activation Following Preconditioning Injury. (United States)

    Kwon, Min Jung; Shin, Hae Young; Cui, Yuexian; Kim, Hyosil; Thi, Anh Hong Le; Choi, Jun Young; Kim, Eun Young; Hwang, Dong Hoon; Kim, Byung Gon


    CNS neurons in adult mammals do not spontaneously regenerate axons after spinal cord injury. Preconditioning peripheral nerve injury allows the dorsal root ganglia (DRG) sensory axons to regenerate beyond the injury site by promoting expression of regeneration-associated genes. We have previously shown that peripheral nerve injury increases the number of macrophages in the DRGs and that the activated macrophages are critical to the enhancement of intrinsic regeneration capacity. The present study identifies a novel chemokine signal mediated by CCL2 that links regenerating neurons with proregenerative macrophage activation. Neutralization of CCL2 abolished the neurite outgrowth activity of conditioned medium obtained from neuron-macrophage cocultures treated with cAMP. The neuron-macrophage interactions that produced outgrowth-promoting conditioned medium required CCL2 in neurons and CCR2/CCR4 in macrophages. The conditioning effects were abolished in CCL2-deficient mice at 3 and 7 d after sciatic nerve injury, but CCL2 was dispensable for the initial growth response and upregulation of GAP-43 at the 1 d time point. Intraganglionic injection of CCL2 mimicked conditioning injury by mobilizing M2-like macrophages. Finally, overexpression of CCL2 in DRGs promoted sensory axon regeneration in a rat spinal cord injury model without harmful side effects. Our data suggest that CCL2-mediated neuron-macrophage interaction plays a critical role for amplification and maintenance of enhanced regenerative capacity by preconditioning peripheral nerve injury. Manipulation of chemokine signaling mediating neuron-macrophage interactions may represent a novel therapeutic approach to promote axon regeneration after CNS injury.

  7. Modulation of neuronal sodium channels by the sea anemone peptide BDS-I. (United States)

    Liu, Pin; Jo, Sooyeon; Bean, Bruce P


    Blood-depressing substance I (BDS-I), a 43 amino-acid peptide from sea anemone venom, is used as a specific inhibitor of Kv3-family potassium channels. We found that BDS-I acts with even higher potency to modulate specific types of voltage-dependent sodium channels. In rat dorsal root ganglion (DRG) neurons, 3 μM BDS-I strongly enhanced tetrodotoxin (TTX)-sensitive sodium current but weakly inhibited TTX-resistant sodium current. In rat superior cervical ganglion (SCG) neurons, which express only TTX-sensitive sodium current, BDS-I enhanced current elicited by small depolarizations and slowed decay of currents at all voltages (EC(50) ∼ 300 nM). BDS-I acted with exceptionally high potency and efficacy on cloned human Nav1.7 channels, slowing inactivation by 6-fold, with an EC(50) of approximately 3 nM. BDS-I also slowed inactivation of sodium currents in N1E-115 neuroblastoma cells (mainly from Nav1.3 channels), with an EC(50) ∼ 600 nM. In hippocampal CA3 pyramidal neurons (mouse) and cerebellar Purkinje neurons (mouse and rat), BDS-I had only small effects on current decay (slowing inactivation by 20-50%), suggesting relatively weak sensitivity of Nav1.1 and Nav1.6 channels. The biggest effect of BDS-I in central neurons was to enhance resurgent current in Purkinje neurons, an effect reflected in enhancement of sodium current during the repolarization phase of Purkinje neuron action potentials. Overall, these results show that BDS-I acts to modulate sodium channel gating in a manner similar to previously known neurotoxin receptor site 3 anemone toxins but with different isoform sensitivity. Most notably, BDS-I acts with very high potency on human Nav1.7 channels.

  8. P2X7 receptors in satellite glial cells mediate high functional expression of P2X3 receptors in immature dorsal root ganglion neurons

    Directory of Open Access Journals (Sweden)

    Chen Yong


    Full Text Available Abstract Background The purinergic P2X3 receptor (P2X3R expressed in the dorsal root ganglion (DRG sensory neuron and the P2X7 receptor (P2X7R expressed in the surrounding satellite glial cell (SGC are two major receptors participating in neuron-SGC communication in adult DRGs. Activation of P2X7Rs was found to tonically reduce the expression of P2X3Rs in DRGs, thus inhibiting the abnormal pain behaviors in adult rats. P2X receptors are also actively involved in sensory signaling in developing rodents. However, very little is known about the developmental change of P2X7Rs in DRGs and the interaction between P2X7Rs and P2X3Rs in those animals. We therefore examined the expression of P2X3Rs and P2X7Rs in postnatal rats and determined if P2X7R-P2X3R control exists in developing rats. Findings We immunostained DRGs of immature rats and found that P2X3Rs were expressed only in neurons and P2X7Rs were expressed only in SGCs. Western blot analyses indicated that P2X3R expression decreased while P2X7R expression increased with the age of rats. Electrophysiological studies showed that the number of DRG neurons responding to the stimulation of the P2XR agonist, α,β-meATP, was higher and the amplitudes of α,β-meATP-induced depolarizations were larger in immature DRG neurons. As a result, P2X3R-mediated flinching responses were much more pronounced in immature rats than those found in adult rats. When we reduced P2X7R expression with P2X7R-siRNA in postnatal and adult rats, P2X3R-mediated flinch responses were greatly enhanced in both rat populations. Conclusions These results show that the P2X7R expression increases as rats age. In addition, P2X7Rs in SGCs exert inhibitory control on the P2X3R expression and function in sensory neurons of immature rats, just as observed in adult rats. Regulation of P2X7R expression is likely an effective way to control P2X3R activity and manage pain relief in infants.

  9. The neuronal ceroid lipofuscinosis Cln8 gene expression is developmentally regulated in mouse brain and up-regulated in the hippocampal kindling model of epilepsy

    Directory of Open Access Journals (Sweden)

    Kuronen Mervi


    Full Text Available Abstract Background The neuronal ceroid lipofuscinoses (NCLs are a group of inherited neurodegenerative disorders characterized by accumulation of autofluorescent material in many tissues, especially in neurons. Mutations in the CLN8 gene, encoding an endoplasmic reticulum (ER transmembrane protein of unknown function, underlie NCL phenotypes in humans and mice. The human phenotype is characterized by epilepsy, progressive psychomotor deterioration and visual loss, while motor neuron degeneration (mnd mice with a Cln8 mutation show progressive motor neuron dysfunction and retinal degeneration. Results We investigated spatial and temporal expression of Cln8 messenger ribonucleic acid (mRNA using in situ hybridization, reverse transcriptase polymerase chain reaction (RT-PCR and northern blotting. Cln8 is ubiquitously expressed at low levels in embryonic and adult tissues. In prenatal embryos Cln8 is most prominently expressed in the developing gastrointestinal tract, dorsal root ganglia (DRG and brain. In postnatal brain the highest expression is in the cortex and hippocampus. Expression of Cln8 mRNA in the central nervous system (CNS was also analyzed in the hippocampal electrical kindling model of epilepsy, in which Cln8 expression was rapidly up-regulated in hippocampal pyramidal and granular neurons. Conclusion Expression of Cln8 in the developing and mature brain suggests roles for Cln8 in maturation, differentiation and supporting the survival of different neuronal populations. The relevance of Cln8 up-regulation in hippocampal neurons of kindled mice should be further explored.

  10. Electrophysiological evidence for the existence of a rare population of C-fiber low threshold mechanoreceptive (C-LTM) neurons in glabrous skin of the rat hindpaw. (United States)

    Djouhri, Laiche


    The mammalian skin in innervated by distinct classes of low-threshold mechanoreceptive (LTM) primary afferent neurons that are classified as Aβ-, Aδ- or C-LTMs according to their axonal conduction velocities (CVs). C-LTMs are thought to signal pleasant and erotic touch sensations in humans, and to exist only in the hairy skin of primates and other species. Using intracellular recordings from rat L4/L5 dorsal root ganglion (DRG) neurons that were classified in vivo as C-nociceptors or C-LTMs, according to their dorsal root CVs and their responses to mechanical and thermal stimuli, the present study provides the first electrophysiological evidence that C-LTMs exist in the glabrous skin of the rat's hindpaw. Indeed 6.4% (5/78) of the total sample of lumbar C-fiber DRG neurons with receptive fields in the glabrous skin of the rat hindpaw were C-LTMs. The electrophysiological properties of this rare subpopulation of C-fiber neurons (mean CV=0.48±0.06m/s) are distinct from those of C-fiber high threshold mechanoreceptors (HTMs). Indeed, their mean mechanical (1.7±1.1mN) and electrical (4.0±0.4V) thresholds was significantly different from that of C-HTMs. They also exhibited faster action potential and afterhyperpolarization kinetics than C-HTMs. The present study lends support to previous studies that have provided indirect evidence for the presence of C-LTMs in glabrous skin. If C-LTMs are present in human glabrous skin, they may, in this type of skin, represent a novel peripheral neuronal substrate for the pleasant/social touch sensation, and account for or contribute to touch hypersensitivity after injury.

  11. Regulation of voltage-gated Ca(2+) currents by Ca(2+)/calmodulin-dependent protein kinase II in resting sensory neurons. (United States)

    Kostic, Sandra; Pan, Bin; Guo, Yuan; Yu, Hongwei; Sapunar, Damir; Kwok, Wai-Meng; Hudmon, Andy; Wu, Hsiang-En; Hogan, Quinn H


    Calcium/calmodulin-dependent protein kinase II (CaMKII) is recognized as a key element in encoding depolarization activity of excitable cells into facilitated voltage-gated Ca(2+) channel (VGCC) function. Less is known about the participation of CaMKII in regulating VGCCs in resting cells. We examined constitutive CaMKII control of Ca(2+) currents in peripheral sensory neurons acutely isolated from dorsal root ganglia (DRGs) of adult rats. The small molecule CaMKII inhibitor KN-93 (1.0μM) reduced depolarization-induced ICa by 16-30% in excess of the effects produced by the inactive homolog KN-92. The specificity of CaMKII inhibition on VGCC function was shown by the efficacy of the selective CaMKII blocking peptide autocamtide-2-related inhibitory peptide in a membrane-permeable myristoylated form, which also reduced VGCC current in resting neurons. Loss of VGCC currents is primarily due to reduced N-type current, as application of mAIP selectively reduced N-type current by approximately 30%, and prior N-type current inhibition eliminated the effect of mAIP on VGCCs, while prior block of L-type channels did not reduce the effect of mAIP on total ICa. T-type currents were not affected by mAIP in resting DRG neurons. Transduction of sensory neurons in vivo by DRG injection of an adeno-associated virus expressing AIP also resulted in a loss of N-type currents. Together, these findings reveal a novel molecular adaptation whereby sensory neurons retain CaMKII support of VGCCs despite remaining quiescent.

  12. Activation of CB1 inhibits NGF-induced sensitization of TRPV1 in adult mouse afferent neurons. (United States)

    Wang, Z-Y; McDowell, T; Wang, P; Alvarez, R; Gomez, T; Bjorling, D E


    Transient receptor potential vanilloid 1 (TRPV1)-containing afferent neurons convey nociceptive signals and play an essential role in pain sensation. Exposure to nerve growth factor (NGF) rapidly increases TRPV1 activity (sensitization). In the present study, we investigated whether treatment with the selective cannabinoid receptor 1 (CB1) agonist arachidonyl-2'-chloroethylamide (ACEA) affects NGF-induced sensitization of TRPV1 in adult mouse dorsal root ganglion (DRG) afferent neurons. We found that CB1, NGF receptor tyrosine kinase A (trkA), and TRPV1 are present in cultured adult mouse small- to medium-sized afferent neurons and treatment with NGF (100ng/ml) for 30 min significantly increased the number of neurons that responded to capsaicin (as indicated by increased intracellular Ca(2 +) concentration). Pretreatment with the CB1 agonist ACEA (10nM) inhibited the NGF-induced response, and this effect of ACEA was reversed by a selective CB1 antagonist. Further, pretreatment with ACEA inhibited NGF-induced phosphorylation of AKT. Blocking PI3 kinase activity also attenuated the NGF-induced increase in the number of neurons that responded to capsaicin. Our results indicate that the analgesic effect of CB1 activation may in part be due to inhibition of NGF-induced sensitization of TRPV1 and also that the effect of CB1 activation is at least partly mediated by attenuation of NGF-induced increased PI3 signaling.

  13. Transcriptional regulation of metabotropic glutamate receptor 2/3 expression by the NF-κB pathway in primary dorsal root ganglia neurons: a possible mechanism for the analgesic effect of L-acetylcarnitine

    Directory of Open Access Journals (Sweden)

    Nicoletti Ferdinando


    Full Text Available Abstract L-acetylcarnitine (LAC, a drug utilized for the treatment of neuropathic pain in humans, has been shown to induce analgesia in rodents by up-regulating the expression of metabotropic glutamate receptor 2 (mGlu2 in dorsal root ganglia (DRG. We now report that LAC-induced upregulation of mGlu2 expression in DRG cultures involves transcriptional activation mediated by nuclear factor-kappaB (NF-κB. A single application of LAC (250 μM to DRG cultures induced a transient increase in mGlu2 mRNA, which was observable after 1 hour and was no longer detectable after 1 to 4 days. In contrast, LAC treatment had no effect on mGlu3 mRNA expression. Pharmacological inhibition of NF-κB binding to DNA by caffeic acid phenethyl ester (CAPE (2.5 μg/ml for 30 minutes reduced the constitutive expression of mGlu2 and mGlu3 mRNA after 1–4 days and reduced the constitutive expression of mGlu2/3 protein at 4 days. This evidence combined with the expression of p65/RelA and c-Rel in DRG neurons indicated that expression of mGlu2 and mGlu3 is endogenously regulated by the NF-κB family of transcription factors. Consistent with this idea, the transient increase in mGlu2 mRNA induced by LAC after 1 hour was completely suppressed by CAPE. Furthermore, LAC induced an increase in the acetylation of p65/RelA, a process that enhances the transcriptional activity of p65/RelA. These results are consistent with the hypothesis that LAC selectively induces the expression of mGlu2 by acting as a donor of acetyl groups, thus enhancing the activity of the NF-κB family of transcription factors. Accordingly, we show that carnitine, which has no effect on pain thresholds, had no effect on p65/RelA acetylation and did not enhance mGlu2 expression. Taken together, these results demonstrate that expression of mGlu2 and mGlu3 mRNA is regulated by the NF-κB transcriptional machinery, and that agents that increase acetylation and activation of NF-κB transcription factors might

  14. Study of a new neuron

    CERN Document Server

    Adler, Stephen Louis; Weckel, J D


    We study a modular neuron alternative to the McCulloch-Pitts neuron that arises naturally in analog devices in which the neuron inputs are represented as coherent oscillatory wave signals. Although the modular neuron can compute XOR at the one neuron level, it is still characterized by the same Vapnik-Chervonenkis dimension as the standard neuron. We give the formulas needed for constructing networks using the new neuron and training them using back-propagation. A numerical study of the modular neuron on two data sets is presented, which demonstrates that the new neuron performs at least as well as the standard neuron.

  15. The aminoglycosides modulate the acid-sensing ionic channel currents in dorsal root ganglion neurons from the rat. (United States)

    Garza, Aníbal; López-Ramírez, Omar; Vega, Rosario; Soto, Enrique


    Acid-sensing ionic channels (ASICs) have been shown to have a significant role in a growing number of physiological and pathological processes, such as nociception, synaptic transmission and plasticity, mechanosensation, and acidosis-induced neuronal injury. The discovery of pharmacological agents targeting ASICs has significant therapeutic potential and use as a research tool. In our work, we studied the action of transient perfusion (5-15 s) of aminoglycosides (AGs) (streptomycin and neomycin) on the proton-gated ionic currents in dorsal root ganglion (DRG) neurons of the rat and in human embryonic kidney (HEK)-293 cells. In DRG neurons, streptomycin and neomycin (30 microM) produced a significant, concentration-dependent, and reversible reduction in the amplitude of the proton-gated current, and a slowing of the desensitization rate of the ASIC current. Gentamycin (30 microM) also showed a significant reversible action on the ASIC currents. The curves of the pH effect for streptomycin and neomycin indicated that their effect was not significantly affected by pH. In HEK-293 cells, streptomycin (30 microM) produced a significant reduction in the amplitude of the proton-gated current. Neomycin and gentamycin had no significant action. Reduction of extracellular Ca(2+) concentration produced a significant increase in the action of streptomycin and neomycin on the desensitization time course of ASIC currents. These results indicate that ASICs are molecular targets for AGs, which may contribute to the understanding of their actions on excitable cells. Moreover, AGs may constitute a source to develop novel molecules with a greater affinity, specificity, and selectivity for the different ASIC subunits.

  16. Cerebrospinal Fluid A beta(1-40) Improves Differential Dementia Diagnosis in Patients with Intermediate P-tau(181P) Levels

    NARCIS (Netherlands)

    Slaets, Sylvie; Le Bastard, Nathalie; Martin, Jean-Jacques; Sleegers, Kristel; Van Broeckhoven, Christine; De Deyn, Peter Paul; Engelborghs, Sebastiaan


    It is assumed that the concentration of amyloid-beta(1-40) (A beta(1-40)) in cerebrospinal fluid (CSF) reflects the total amount of A beta protein in the brain and thus allows a better interpretation of inter-individual differences in A beta quantity than the A beta(1-42) concentration. In this stud

  17. Cajal bodies in neurons. (United States)

    Lafarga, Miguel; Tapia, Olga; Romero, Ana M; Berciano, Maria T


    Cajal is commonly regarded as the father of modern neuroscience in recognition of his fundamental work on the structure of the nervous system. But Cajal also made seminal contributions to the knowledge of nuclear structure in the early 1900s, including the discovery of the "accessory body" later renamed "Cajal body" (CB). This important nuclear structure has emerged as a center for the assembly of ribonucleoproteins (RNPs) required for splicing, ribosome biogenesis and telomere maintenance. The modern era of CB research started in the 1990s with the discovery of coilin, now known as a scaffold protein of CBs, and specific probes for small nuclear RNAs (snRNAs). In this review, we summarize what we have learned in the recent decades concerning CBs in post-mitotic neurons, thereby ruling out dynamic changes in CB functions during the cell cycle. We show that CBs are particularly prominent in neurons, where they frequently associate with the nucleolus. Neuronal CBs are transcription-dependent nuclear organelles. Indeed, their number dynamically accommodates to support the high neuronal demand for splicing and ribosome biogenesis required for sustaining metabolic and bioelectrical activity. Mature neurons have canonical CBs enriched in coilin, survival motor neuron protein and snRNPs. Disruption and loss of neuronal CBs associate with severe neuronal dysfunctions in several neurological disorders such as motor neuron diseases. In particular, CB depletion in motor neurons seems to reflect a perturbation of transcription and splicing in spinal muscular atrophy, the most common genetic cause of infant mortality.

  18. Key residues for the oligomerization of A{beta}42 protein in Alzheimer's disease

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, Sam [Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095 (United States); Guo, Zhefeng, E-mail: [Department of Neurology, Brain Research Institute, Molecular Biology Institute, University of California, Los Angeles, CA 90095 (United States)


    Highlights: Black-Right-Pointing-Pointer A{beta} oligomers are neurotoxins and likely the causing agents for Alzheimer's disease. Black-Right-Pointing-Pointer A{beta}42 fusion protein form globular oligomers. Black-Right-Pointing-Pointer A{beta}42 fusion protein oligomers contain SDS-resistant tetramers and hexamers. Black-Right-Pointing-Pointer Cysteine substitutions at residues 31, 32, 34, 39-41 disrupt A{beta}42 oligomerization. -- Abstract: Deposition of amyloid fibrils consisting of amyloid {beta} (A{beta}) protein as senile plaques in the brain is a pathological hallmark of Alzheimer's disease. However, a growing body of evidence shows that soluble A{beta} oligomers correlate better with dementia than fibrils, suggesting that A{beta} oligomers may be the primary toxic species. The structure and oligomerization mechanism of these A{beta} oligomers are crucial for developing effective therapeutics. Here we investigated the oligomerization of A{beta}42 in the context of a fusion protein containing GroES and ubiquitin fused to the N-terminus of A{beta} sequence. The presence of fusion protein partners, in combination with a denaturing buffer containing 8 M urea at pH 10, is unfavorable for A{beta}42 aggregation, thus allowing only the most stable structures to be observed. Transmission electron microscopy showed that A{beta}42 fusion protein formed globular oligomers, which bound weakly to thioflavin T and Congo red. SDS-PAGE shows that A{beta}42 fusion protein formed SDS-resistant hexamers and tetramers. In contrast, A{beta}40 fusion protein remained as monomers on SDS gel, suggesting that the oligomerization of A{beta}42 fusion protein is not due to the fusion protein partners. Cysteine scanning mutagenesis at 22 residue positions further revealed that single cysteine substitutions of the C-terminal hydrophobic residues (I31, I32, L34, V39, V40, and I41) led to disruption of hexamer and tetramer formation, suggesting that hydrophobic interactions

  19. Hyccin, the molecule mutated in the leukodystrophy hypomyelination and congenital cataract (HCC, is a neuronal protein.

    Directory of Open Access Journals (Sweden)

    Elisabetta Gazzerro

    Full Text Available "Hypomyelination and Congenital Cataract", HCC (MIM #610532, is an autosomal recessive disorder characterized by congenital cataract and diffuse cerebral and peripheral hypomyelination. HCC is caused by deficiency of Hyccin, a protein whose biological role has not been clarified yet. Since the identification of the cell types expressing a protein of unknown function can contribute to define the physiological context in which the molecule is explicating its function, we analyzed the pattern of Hyccin expression in the central and peripheral nervous system (CNS and PNS. Using heterozygous mice expressing the b-galactosidase (LacZ gene under control of the Hyccin gene regulatory elements, we show that the gene is primarily expressed in neuronal cells. Indeed, Hyccin-LacZ signal was identified in CA1 hippocampal pyramidal neurons, olfactory bulb, and cortical pyramidal neurons, while it did not colocalize with oligodendroglial or astrocytic markers. In the PNS, Hyccin was detectable only in axons isolated from newborn mice. In the brain, Hyccin transcript levels were higher in early postnatal development (postnatal days 2 and 10 and then declined in adult mice. In a model of active myelinogenesis, organotypic cultures of rat Schwann cells (SC/Dorsal Root Ganglion (DRG sensory neurons, Hyccin was detected along the neurites, while it was absent from SC. Intriguingly, the abundance of the molecule was upregulated at postnatal days 10 and 15, in the initial steps of myelinogenesis and then declined at 30 days when the process is complete. As Hyccin is primarily expressed in neurons and its mutation leads to hypomyelination in human patients, we suggest that the protein is involved in neuron-to-glia signalling to initiate or maintain myelination.

  20. Insect resistance to sugar beet pests mediated by a Beta vulgaris proteinase inhibitor transgene (United States)

    We transformed sugar beet (Beta vulgaris) hairy roots and Nicotiana benthamiana plants with a Beta vulgaris root gene (BvSTI) that codes for a serine proteinase inhibitor. BvSTI is a root gene cloned from the F1016 breeding line that has moderate levels of resistance to the sugar beet root maggot ...

  1. Noise and Neuronal Heterogeneity

    CERN Document Server

    Barber, Michael J


    We consider signal transaction in a simple neuronal model featuring intrinsic noise. The presence of noise limits the precision of neural responses and impacts the quality of neural signal transduction. We assess the signal transduction quality in relation to the level of noise, and show it to be maximized by a non-zero level of noise, analogous to the stochastic resonance effect. The quality enhancement occurs for a finite range of stimuli to a single neuron; we show how to construct networks of neurons that extend the range. The range increases more rapidly with network size when we make use of heterogeneous populations of neurons with a variety of thresholds, rather than homogeneous populations of neurons all with the same threshold. The limited precision of neural responses thus can have a direct effect on the optimal network structure, with diverse functional properties of the constituent neurons supporting an economical information processing strategy that reduces the metabolic costs of handling a broad...

  2. Trigeminal ganglion neurons of mice show intracellular chloride accumulation and chloride-dependent amplification of capsaicin-induced responses.

    Directory of Open Access Journals (Sweden)

    Nicole Schöbel

    Full Text Available Intracellular Cl(- concentrations ([Cl(-](i of sensory neurons regulate signal transmission and signal amplification. In dorsal root ganglion (DRG and olfactory sensory neurons (OSNs, Cl(- is accumulated by the Na(+-K(+-2Cl(- cotransporter 1 (NKCC1, resulting in a [Cl(-](i above electrochemical equilibrium and a depolarizing Cl(- efflux upon Cl(- channel opening. Here, we investigate the [Cl(-](i and function of Cl(- in primary sensory neurons of trigeminal ganglia (TG of wild type (WT and NKCC1(-/- mice using pharmacological and imaging approaches, patch-clamping, as well as behavioral testing. The [Cl(-](i of WT TG neurons indicated active NKCC1-dependent Cl(- accumulation. Gamma-aminobutyric acid (GABA(A receptor activation induced a reduction of [Cl(-](i as well as Ca(2+ transients in a corresponding fraction of TG neurons. Ca(2+ transients were sensitive to inhibition of NKCC1 and voltage-gated Ca(2+ channels (VGCCs. Ca(2+ responses induced by capsaicin, a prototypical stimulus of transient receptor potential vanilloid subfamily member-1 (TRPV1 were diminished in NKCC1(-/- TG neurons, but elevated under conditions of a lowered [Cl(-](o suggesting a Cl(--dependent amplification of capsaicin-induced responses. Using next generation sequencing (NGS, we found expression of different Ca(2+-activated Cl(- channels (CaCCs in TGs of mice. Pharmacological inhibition of CaCCs reduced the amplitude of capsaicin-induced responses of TG neurons in Ca(2+ imaging and electrophysiological recordings. In a behavioral paradigm, NKCC1(-/- mice showed less avoidance of the aversive stimulus capsaicin. In summary, our results strongly argue for a Ca(2+-activated Cl(--dependent signal amplification mechanism in TG neurons that requires intracellular Cl(- accumulation by NKCC1 and the activation of CaCCs.

  3. Mesmerising mirror neurons. (United States)

    Heyes, Cecilia


    Mirror neurons have been hailed as the key to understanding social cognition. I argue that three currents of thought-relating to evolution, atomism and telepathy-have magnified the perceived importance of mirror neurons. When they are understood to be a product of associative learning, rather than an adaptation for social cognition, mirror neurons are no longer mesmerising, but they continue to raise important questions about both the psychology of science and the neural bases of social cognition.

  4. Effects of dragon's blood resin and its component loureirin B on tetrodotoxin-sensitive voltage-gated sodium currents in rat dorsal root ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    LIU Xiangming; CHEN Su; YIN Shijin; MEI Zhinan


    Using whole-cell patch clamp technique on the membrane of freshly isolated dorsal root ganglion(DRG)neurons,the effects of dragon's blood resin and its important component Ioureirin B on tetrodotoxin-sensitive(TTX-S)voltage-gated sodium currents were observed.The results show that both blood resin and loureirin B could suppress TTX-S voltage-gated sodium currents in a dose-dependent way.The peak current amplitudes and the steady-state activation and inactivation curves are also made to shift by 0.05% blood resin and 0.2 mmol/L loureirin B.These results demonstrate that the effects of blood resin on TTX-S sodium current may contribute to loureirin B in blood resin.Perhaps the analgesic effect of blood resin is caused partly by loureirin B directly interfering with the nociceptive transmission of primary sensory neurons.

  5. 大鼠背根节慢性压迫或急性分离引起的cGMP-PKG信号通路持续激活介导背根节神经元的异常兴奋性和痛觉过敏%Activation of cGMP-PKG signaling pathway contributes to neuronal hyperexcitability and hyperalgesia after in vivo prolonged compression or in vitro acute dissociation of dorsal root ganglion in rats

    Institute of Scientific and Technical Information of China (English)

    黄志江; 李浩川; 刘苏; 宋学军


    Injury or inflammation affecting sensory neurons in the dorsal root ganglia (DRG) causes hyperexcitability of DRG neurons that can lead to spinal central sensitization and neuropathic pain.Recent studies have indicated that,following chronic compression of DRG (CCD) or acute dissociation of DRG (ADD) treatment,both hyperexcitability of neurons in intact DRG and behaviorally expressed hyperalgesia are maintained by activity in cGMP-PKG signaling pathway.Here,we provide evidence supporting the idea that CCD or ADD treatment activates cGMP-PKA signaling pathway in the DRG neurons.The results showed that CCD or ADD results in increase of levels of cGMP concentration and expression of PKG-I mRNA,as well as PKG-I protein in DRG.CCD or ADD treatedDRG neurons become hyperexcitable and exhibit increased responsiveness to the activators of cGMP-PKG pathway,8-Br-cGMP and Sp-cGMP.Hyperexcitability of the injured neurons is inhibited by cGMP-PKG pathway inhibitors,ODQ and Rp-8-pCPT-cGMPS.In vivo delivery of Rp-8-pCPT-cGMPS into the compressed ganglion within the intervertebral foramen suppresses CCD-induced thermal hyperalgesia.These findings indicate that the in vivo CCD or in vitro ADD treatment can activate the cGMP-PKG signaling pathway,and that continuing activation of cGMP-PKG pathway is required to maintain DRG neuronal hyperexcitability and/or hyperalgesia after these two dissimilar forms of injury-related stress.%背根节(dorsal root ganglion,DRG)损伤或炎症可导致DRG神经元兴奋性异常增强和痛觉过敏.我们近期研究显示,长期慢性在体压迫(chronic compression of DRG,CCD)或急性离体分离(acute dissociation of DRG,ADD)背根节导致的神经元兴奋性异常增强和痛觉过敏受环鸟苷酸(cGMP)-蛋白激酶G(PKG)信号通路活动的调控.本研究采用大鼠CCD模型和ADD模型,直接在DRG上检测cGMP浓度和PKG mRNA及其蛋白质的表达,进一步证明了cGMP-PKG信号通路活动在CCD和ADDDRG所致神经元兴奋性

  6. The Molecular Motor KIF1A Transports the TrkA Neurotrophin Receptor and Is Essential for Sensory Neuron Survival and Function. (United States)

    Tanaka, Yosuke; Niwa, Shinsuke; Dong, Ming; Farkhondeh, Atena; Wang, Li; Zhou, Ruyun; Hirokawa, Nobutaka


    KIF1A is a major axonal transport motor protein, but its functional significance remains elusive. Here we show that KIF1A-haploinsufficient mice developed sensory neuropathy. We found progressive loss of TrkA(+) sensory neurons in Kif1a(+/-) dorsal root ganglia (DRGs). Moreover, axonal transport of TrkA was significantly disrupted in Kif1a(+/-) neurons. Live imaging and immunoprecipitation assays revealed that KIF1A bound to TrkA-containing vesicles through the adaptor GTP-Rab3, suggesting that TrkA is a cargo of the KIF1A motor. Physiological measurements revealed a weaker capsaicin response in Kif1a(+/-) DRG neurons. Moreover, these neurons were hyposensitive to nerve growth factor, which could explain the reduced neuronal survival and the functional deficiency of the pain receptor TRPV1. Because phosphatidylinositol 3-kinase (PI3K) signaling significantly rescued these phenotypes and also increased Kif1a mRNA, we propose that KIF1A is essential for the survival and function of sensory neurons because of the TrkA transport and its synergistic support of the NGF/TrkA/PI3K signaling pathway.

  7. Pacemaking Kisspeptin Neurons (United States)

    Kelly, Martin J.; Zhang, Chunguang; Qiu, Jian; Rønnekleiv, Oline K.


    Kisspeptin (Kiss1) neurons are vital for reproduction. GnRH neurons express the kisspeptin receptor, GPR 54, and kisspeptins potently stimulate the release of GnRH by depolarising and inducing sustained action potential firing in GnRH neurons. As such Kiss1 neurons may be the pre-synaptic pacemaker neurons in the hypothalamic circuitry that controls reproduction. There are at least two different populations of Kiss1 neurons: one in the rostral periventricular area (RP3V) that is stimulated by oestrogens and the other in the arcuate nucleus that is inhibited by oestrogens. How each of these Kiss1 neuronal populations participate in the regulation of the reproductive cycle is currently under intense investigation. Based on electrophysiological studies in the guinea pig and mouse, Kiss1 neurons in general are capable of generating burst firing behavior. Essentially all Kiss1 neurons, which have been studied thus far in the arcuate nucleus, express the ion channels necessary for burst firing, which include hyperpolarization-activated, cyclic nucleotide gated cation (HCN) channels and the T-type calcium (Cav3.1) channels. Under voltage clamp conditions, these channels produce distinct currents that under current clamp conditions can generate burst firing behavior. The future challenge is to identify other key channels and synaptic inputs involved in the regulation of the firing properties of Kiss1 neurons and the physiological regulation of the expression of these channels and receptors by oestrogens and other hormones. The ultimate goal is to understand how Kiss1 neurons control the different phases of GnRH neurosecretion and hence reproduction. PMID:23884368

  8. A[Beta] Deposits in Older Non-Demented Individuals with Cognitive Decline Are Indicative of Preclinical Alzheimer's Disease (United States)

    Villemagne, V. L.; Pike, K. E.; Darby, D.; Maruff, P.; Savage, G.; Ng, S.; Ackermann, U.; Cowie, T. F.; Currie, J.; Chan, S. G.; Jones, G.; Tochon-Danguy, H.; O'Keefe, G.; Masters, C. L.; Rowe, C. C.


    Approximately 30% of healthy persons aged over 75 years show A[beta] deposition at autopsy. It is postulated that this represents preclinical Alzheimer's disease (AD). We evaluated the relationship between A[beta] burden as assessed by PiB PET and cognitive decline in a well-characterized, non-demented, elderly cohort. PiB PET studies and…

  9. Juvenil neuronal ceroid lipofuscinosis

    DEFF Research Database (Denmark)

    Ostergaard, J R; Hertz, Jens Michael


    Neuronal ceroid-lipofuscinosis is a group of neurodegenerative diseases which are characterized by an abnormal accumulation of lipopigment in neuronal and extraneuronal cells. The diseases can be differentiated into several subgroups according to age of onset, the clinical picture, neurophysiolog...

  10. Corticospinal mirror neurons. (United States)

    Kraskov, A; Philipp, R; Waldert, S; Vigneswaran, G; Quallo, M M; Lemon, R N


    Here, we report the properties of neurons with mirror-like characteristics that were identified as pyramidal tract neurons (PTNs) and recorded in the ventral premotor cortex (area F5) and primary motor cortex (M1) of three macaque monkeys. We analysed the neurons' discharge while the monkeys performed active grasp of either food or an object, and also while they observed an experimenter carrying out a similar range of grasps. A considerable proportion of tested PTNs showed clear mirror-like properties (52% F5 and 58% M1). Some PTNs exhibited 'classical' mirror neuron properties, increasing activity for both execution and observation, while others decreased their discharge during observation ('suppression mirror-neurons'). These experiments not only demonstrate the existence of PTNs as mirror neurons in M1, but also reveal some interesting differences between M1 and F5 mirror PTNs. Although observation-related changes in the discharge of PTNs must reach the spinal cord and will include some direct projections to motoneurons supplying grasping muscles, there was no EMG activity in these muscles during action observation. We suggest that the mirror neuron system is involved in the withholding of unwanted movement during action observation. Mirror neurons are differentially recruited in the behaviour that switches rapidly between making your own movements and observing those of others.

  11. Culturing rat hippocampal neurons. (United States)

    Audesirk, G; Audesirk, T; Ferguson, C


    Cultured neurons are widely used to investigate the mechanisms of neurotoxicity. Embryonic rat hippocampal neurons may be grown as described under a wide variety of conditions to suit differing experimental procedures, including electrophysiology, morphological analysis of neurite development, and various biochemical and molecular analyses.

  12. Effects of postnatal anti-NGF on the development of CGRP-IR neurons in the dorsal root ganglion. (United States)

    Tonra, J R; Mendell, L M


    Experiments were undertaken to examine anatomical correlates of physiological effects of rabbit sera raised against nerve growth factor (anti-NGF) on nociceptive afferents. This antiserum has been shown to deplete the population of A-delta high threshold mechanoreceptors and to reduce neurogenic vasodilatation. Because numerous studies implicate calcitonin gene related peptide (CGRP)-containing sensory neurons in these effects, immunocytochemical and anatomical techniques were used to examine the normal development of CGRP-immunoreactive (-IR) neurons in the dorsal root ganglion (DRG) of rats from 13 days to 19 weeks of age, and to compare this to the development in rats treated neonatally (postnatal days 2-14) with anti-NGF. In controls the rate of increase in the mean diameter of CGRP-IR cells was substantially greater between 13 days and 5 weeks of age than it was between 5 weeks and 19 weeks, in contrast to CGRP-negative neurons whose rate of growth remained relatively constant. Anti-NGF had no significant effect on growth rate, but rats treated with anti-NGF exhibited a reduced proportion of CGRP-IR neurons at 5 weeks. This deficit was reversed by 19 weeks unlike the physiological changes. These results indicate independent regulation of CGRP expression and nociceptor physiology by NGF.

  13. Surgical extraction of human dorsal root ganglia from organ donors and preparation of primary sensory neuron cultures. (United States)

    Valtcheva, Manouela V; Copits, Bryan A; Davidson, Steve; Sheahan, Tayler D; Pullen, Melanie Y; McCall, Jordan G; Dikranian, Krikor; Gereau, Robert W


    Primary cultures of rodent sensory neurons are widely used to investigate the cellular and molecular mechanisms involved in pain, itch, nerve injury and regeneration. However, translation of these preclinical findings may be greatly improved by direct validation in human tissues. We have developed an approach to extract and culture human sensory neurons in collaboration with a local organ procurement organization (OPO). Here we describe the surgical procedure for extraction of human dorsal root ganglia (hDRG) and the necessary modifications to existing culture techniques to prepare viable adult human sensory neurons for functional studies. Dissociated sensory neurons can be maintained in culture for >10 d, and they are amenable to electrophysiological recording, calcium imaging and viral gene transfer. The entire process of extraction and culturing can be completed in <7 h, and it can be performed by trained graduate students. This approach can be applied at any institution with access to organ donors consenting to tissue donation for research, and is an invaluable resource for improving translational research.

  14. NEURON and Python. (United States)

    Hines, Michael L; Davison, Andrew P; Muller, Eilif


    The NEURON simulation program now allows Python to be used, alone or in combination with NEURON's traditional Hoc interpreter. Adding Python to NEURON has the immediate benefit of making available a very extensive suite of analysis tools written for engineering and science. It also catalyzes NEURON software development by offering users a modern programming tool that is recognized for its flexibility and power to create and maintain complex programs. At the same time, nothing is lost because all existing models written in Hoc, including graphical user interface tools, continue to work without change and are also available within the Python context. An example of the benefits of Python availability is the use of the xml module in implementing NEURON's Import3D and CellBuild tools to read MorphML and NeuroML model specifications.

  15. Imaging calcium in neurons. (United States)

    Grienberger, Christine; Konnerth, Arthur


    Calcium ions generate versatile intracellular signals that control key functions in all types of neurons. Imaging calcium in neurons is particularly important because calcium signals exert their highly specific functions in well-defined cellular subcompartments. In this Primer, we briefly review the general mechanisms of neuronal calcium signaling. We then introduce the calcium imaging devices, including confocal and two-photon microscopy as well as miniaturized devices that are used in freely moving animals. We provide an overview of the classical chemical fluorescent calcium indicators and of the protein-based genetically encoded calcium indicators. Using application examples, we introduce new developments in the field, such as calcium imaging in awake, behaving animals and the use of calcium imaging for mapping single spine sensory inputs in cortical neurons in vivo. We conclude by providing an outlook on the prospects of calcium imaging for the analysis of neuronal signaling and plasticity in various animal models.

  16. NEURON and Python

    Directory of Open Access Journals (Sweden)

    Michael Hines


    Full Text Available The NEURON simulation program now allows Python to be used, alone or in combination with NEURON's traditional Hoc interpreter. Adding Python to NEURON has the immediate benefit of making available a very extensive suite of analysis tools written for engineering and science. It also catalyzes NEURON software development by offering users a modern programming tool that is recognized for its flexibility and power to create and maintain complex programs. At the same time, nothing is lost because all existing models written in Hoc, including GUI tools, continue to work without change and are also available within the Python context. An example of the benefits of Python availability is the use of the XML module in implementing NEURON's Import3D and CellBuild tools to read MorphML and NeuroML model specifications.

  17. Vascular endothelial growth factor-A165b prevents diabetic neuropathic pain and sensory neuronal degeneration. (United States)

    Hulse, Richard P; Beazley-Long, Nicholas; Ved, Nikita; Bestall, Samuel M; Riaz, Hamza; Singhal, Priya; Ballmer Hofer, Kurt; Harper, Steve J; Bates, David O; Donaldson, Lucy F


    Diabetic peripheral neuropathy affects up to half of diabetic patients. This neuronal damage leads to sensory disturbances, including allodynia and hyperalgesia. Many growth factors have been suggested as useful treatments for prevention of neurodegeneration, including the vascular endothelial growth factor (VEGF) family. VEGF-A is generated as two alternative splice variant families. The most widely studied isoform, VEGF-A165a is both pro-angiogenic and neuroprotective, but pro-nociceptive and increases vascular permeability in animal models. Streptozotocin (STZ)-induced diabetic rats develop both hyperglycaemia and many of the resulting diabetic complications seen in patients, including peripheral neuropathy. In the present study, we show that the anti-angiogenic VEGF-A splice variant, VEGF-A165b, is also a potential therapeutic for diabetic neuropathy. Seven weeks of VEGF-A165b treatment in diabetic rats reversed enhanced pain behaviour in multiple behavioural paradigms and was neuroprotective, reducing hyperglycaemia-induced activated caspase 3 (AC3) levels in sensory neuronal subsets, epidermal sensory nerve fibre loss and aberrant sciatic nerve morphology. Furthermore, VEGF-A165b inhibited a STZ-induced increase in Evans Blue extravasation in dorsal root ganglia (DRG), saphenous nerve and plantar skin of the hind paw. Increased transient receptor potential ankyrin 1 (TRPA1) channel activity is associated with the onset of diabetic neuropathy. VEGF-A165b also prevented hyperglycaemia-enhanced TRPA1 activity in an in vitro sensory neuronal cell line indicating a novel direct neuronal mechanism that could underlie the anti-nociceptive effect observed in vivo. These results demonstrate that in a model of Type I diabetes VEGF-A165b attenuates altered pain behaviour and prevents neuronal stress, possibly through an effect on TRPA1 activity.

  18. Acute morphine induces matrix metalloproteinase-9 up-regulation in primary sensory neurons to mask opioid-induced analgesia in mice

    Directory of Open Access Journals (Sweden)

    Liu Yen-Chin


    Full Text Available Abstract Background Despite decades of intense research efforts, actions of acute opioids are not fully understood. Increasing evidence suggests that in addition to well-documented antinociceptive effects opioids also produce paradoxical hyperalgesic and excitatory effects on neurons. However, most studies focus on the pronociceptive actions of chronic opioid exposure. Matrix metalloproteinase 9 (MMP-9 plays an important role in neuroinflammation and neuropathic pain development. We examined MMP-9 expression and localization in dorsal root ganglia (DRGs after acute morphine treatment and, furthermore, the role of MMP-9 in modulating acute morphine-induced analgesia and hyperalgesia in mice. Results Subcutaneous morphine induced a marked up-regulation of MMP-9 protein in DRGs but not spinal cords. Morphine also increased MMP-9 activity and mRNA expression in DRGs. MMP-9 up-regulation peaked at 2 h but returned to the baseline after 24 h. In DRG tissue sections, MMP-9 is expressed in small and medium-sized neurons that co-express mu opioid receptors (MOR. In DRG cultures, MOR agonists morphine, DAMGO, and remifentanil each increased MMP-9 expression in neurons, whereas the opioid receptor antagonist naloxone and the MOR-selective antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP suppressed morphine-induced MMP-9 expression. Notably, subcutaneous morphine-induced analgesia was enhanced and prolonged in Mmp9 knockout mice and also potentiated in wild-type mice receiving intrathecal injection of MMP-9 inhibitors. Consistently, intrathecal injection of specific siRNA targeting MMP-9 reduced MMP-9 expression in DRGs and enhanced and prolonged morphine analgesia. Subcutaneous morphine also produced heat hyperalgesia at 24 h, but this opioid-induced hyperalgesia was not enhanced after MMP-9 deletion or inhibition. Conclusions Transient MMP-9 up-regulation in DRG neurons can mask opioid analgesia, without modulating opioid-induced hyperalgesia

  19. Synthesis of highly magnetic iron nanoparticles suitable for field structuring using a {beta}-diketone surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Huber, D.L. E-mail:; Venturini, E.L.; Martin, J.E.; Provencio, P.P.; Patel, R.J


    We describe the synthesis of highly magnetic iron nanoparticles using a novel surfactant, a {beta}-diketone. We have produced 6 nm iron nanoparticles with an unusually high saturation magnetization of more than 80% the value of bulk iron. Additionally, we measured a particle susceptibility of 14 (MKS units), which is far above the value possible for micron-scale spherical particles. These properties will allow for formation of composites that can be highly structured by magnetic fields.

  20. Structure of the imipenem-hydrolyzing class A beta-lactamase SME-1 from Serratia marcescens. (United States)

    Sougakoff, Wladimir; L'Hermite, Guillaume; Pernot, Lucile; Naas, Thierry; Guillet, Valérie; Nordmann, Patrice; Jarlier, Vincent; Delettré, Jean


    The structure of the beta-lactamase SME-1 from Serratia marcescens, a class A enzyme characterized by its significant activity against imipenem, has been determined to 2.13 A resolution. The overall structure of SME-1 is similar to that of other class A beta-lactamases. In the active-site cavity, most of the residues found in SME-1 are conserved among class A beta-lactamases, except at positions 104, 105 and 237, where a tyrosine, a histidine and a serine are found, respectively, and at position 238, which is occupied by a cysteine forming a disulfide bridge with the other cysteine residue located at position 69. The crucial role played by this disulfide bridge in SME-1 was confirmed by site-directed mutagenesis of Cys69 to Ala, which resulted in a mutant unable to confer resistance to imipenem and all other beta-lactam antibiotics tested. Another striking structural feature found in SME-1 was the short distance separating the side chains of the active serine residue at position 70 and the strictly conserved glutamate at position 166, which is up to 1.4 A shorter in SME-1 compared with other class A beta-lactamases. Consequently, the SME-1 structure cannot accommodate the essential catalytic water molecule found between Ser70 and Glu166 in the other class A beta-lactamases described so far, suggesting that a significant conformational change may be necessary in SME-1 to properly position the hydrolytic water molecule involved in the hydrolysis of the acyl-enzyme intermediate.

  1. Effect of pathogenic mutations on the structure and dynamics of Alzheimer's A beta 42-amyloid oligomers. (United States)

    Kassler, Kristin; Horn, Anselm H C; Sticht, Heinrich


    Converging lines of evidence suggest that soluble A beta-amyloid oligomers play a pivotal role in the pathogenesis of Alzheimer's disease, and present direct effectors of synaptic and cognitive dysfunction. Three pathological E22-A beta-amyloid point mutants (E22G, E22K, E22Q) and the deletion mutant E22 Delta exhibit an enhanced tendency to form prefibrillar aggregates. The present study assessed the effect of these four mutations using molecular dynamics simulations and subsequent structural and energetic analyses. Our data shows that E22 plays a unique role in wild type A beta, since it has a destabilising effect on the oligomer structure due to electrostatic repulsion between adjacent E22 side chains. Mutations in which E22 is replaced by an uncharged residue result in higher oligomer stability. This effect is also observed to a lesser extent for the E22K mutation and is consistent with its lower pathogenicity compared to other mutants. Interestingly, deletion of E22 does not destroy the amyloid fold but is compensated by local changes in the backbone geometry that allow the preservation of a structurally important salt bridge. The finding that all mutant oligomers investigated exhibit higher internal stability than the wild type offers an explanation for the experimentally observed enhanced oligomer formation and stability.

  2. Reduction of the immunostainable length of the hippocampal dentate granule cells' primary cilia in 3xAD-transgenic mice producing human A{beta}{sub 1-42} and tau

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarthy, Balu, E-mail: [Human Health Therapeutics, National Research Council of Canada, Ottawa, ON (Canada); Gaudet, Chantal; Menard, Michel; Brown, Leslie; Atkinson, Trevor [Human Health Therapeutics, National Research Council of Canada, Ottawa, ON (Canada); LaFerla, Frank M. [Department of Neurobiology and Behavior, University of California, Irvine, CA (United States); Ito, Shingo [Human Health Therapeutics, National Research Council of Canada, Ottawa, ON (Canada); Armato, Ubaldo; Dal Pra, Ilaria [Department of Life and Reproduction Sciences, University of Verona Medical School, Verona (Italy); Whitfield, James [Human Health Therapeutics, National Research Council of Canada, Ottawa, ON (Canada)


    Highlights: Black-Right-Pointing-Pointer A{beta} and tau-induced neurofibrillary tangles play a key role in Alzheimer's disease. Black-Right-Pointing-Pointer A{beta}{sub 1-42} and mutant tau protein together reduce the primary cilium length. Black-Right-Pointing-Pointer This shortening likely reduces cilium-dependent neurogenesis and memory function. Black-Right-Pointing-Pointer This provides a model of an A{beta}/tau targeting of a neuronal signaling organelle. -- Abstract: The hippocampal dentate gyrus is one of the two sites of continuous neurogenesis in adult rodents and humans. Virtually all dentate granule cells have a single immobile cilium with a microtubule spine or axoneme covered with a specialized cell membrane loaded with receptors such as the somatostatin receptor 3 (SSTR3), and the p75 neurotrophin receptor (p75{sup NTR}). The signals from these receptors have been reported to stimulate neuroprogenitor proliferation and the post-mitotic maturation of newborn granule cells into functioning granule cells. We have found that in 6-24-months-old triple transgenic Alzheimer's disease model mice (3xTg-AD) producing both A{beta}{sub 1-42} and the mutant human tau protein tau{sub P301L,} the dentate granule cells still had immunostainable SSTR3- and p75{sup NTR}-bearing cilia but they were only half the length of the immunostained cilia in the corresponding wild-type mice. However, the immunostainable length of the granule cell cilia was not reduced either in 2xTg-AD mice accumulating large amounts of A{beta}{sub 1-42} or in mice accumulating only a mutant human tau protein. Thus it appears that a combination of A{beta}{sub 1-42} and tau protein accumulation affects the levels of functionally important receptors in 3xTg-AD mice. These observations raise the important possibility that structural and functional changes in granule cell cilia might have a role in AD.

  3. Single neuron computation

    CERN Document Server

    McKenna, Thomas M; Zornetzer, Steven F


    This book contains twenty-two original contributions that provide a comprehensive overview of computational approaches to understanding a single neuron structure. The focus on cellular-level processes is twofold. From a computational neuroscience perspective, a thorough understanding of the information processing performed by single neurons leads to an understanding of circuit- and systems-level activity. From the standpoint of artificial neural networks (ANNs), a single real neuron is as complex an operational unit as an entire ANN, and formalizing the complex computations performed by real n

  4. Regulatory effect of nerve growth factor on release of substance P in cultured dorsal root ganglion neurons of rat%神经生长因子对培养的大鼠背根神经节神经元P物质释放的调节作用

    Institute of Scientific and Technical Information of China (English)

    杨向东; 刘真; 刘花香; 王丽红; 马春红; 李振中


    Objective To investigate the regulatory effects of nerve growth factor (NGF) on basal and capsaicin-induced release of neuropeptide substance P (SP) in primary cultured embryonic rat dorsal root ganglion (DRG) neurons. Methods DRGs were dissected from 15-day-old embryonic Wistar rats. DRG neurons were dissociated and cultured, and then exposed to different concentrations of NGF (10 ng/mL, 30 ng/mL, or 100 ng/mL) for 72 h. The neurons cultured in media without NGF served as control. RT-PCR were used for detecting the mRNAs of S P and vanilloid receptor 1 (VR1) in the DRG neurons. The SP basal and capsaicin (100 nmol/L)-induced release in the culture were measured by radioimmunoassay (RIA). Results SP mRNA and VR1 mRNA expression increased in primary cultured DRG neurons in a dose-dependent manner of NGF. Both basal release and capsaicin-evoked release of SP increased in NGF-treated DRG neurons compared with in control group. The capsaicin-evoked release of SP also increased in a dose-dependent manner of NGF. Conclusion NGF may promote both basal release and capsaicin-evoked release of SP. NGF might increase the sensitivity of nociceptors by increasing the SP mRNA or VR1 mRNA.%目的 观察神经生长因子(nerve growth factor,NGF)对原代培养的背根神经节(dorsal root ganglion,DRG)神经元中P物质(substance P,SP)的基础释放量和辣椒素诱发释放量的调节效应.方法 将15天胚龄的Wistar大鼠DRG神经元培养于含有不同浓度NGF的DMEM/F12培养液中,不含NGF的培养液培养的神经元作为对照.72小时后,用RT-PCR检测神经元中SP mRNA和辣椒素受体(vanilloid receptor 1,VR1)mRNA的表达,用放射免疫分析(radioimmunoassay,RIA)法检测SP的基础释放量和辣椒素(100 nmol/L)刺激10 min后的诱发释放量.结果 SPmRNA和VR1 mRNA在NGF孵育的标本中表达增加,并与孵育液中NGF的浓度呈剂量依赖关系.SP的基础释放量和辣椒素诱发释放量在NGF孵育的标本中均增加,而且诱

  5. Brain-derived neurotrophic factor promotes vesicular glutamate transporter 3 expression and neurite outgrowth of dorsal root ganglion neurons through the activation of the transcription factors Etv4 and Etv5. (United States)

    Liu, Dong; Liu, Zhen; Liu, Huaxiang; Li, Hao; Pan, Xinliang; Li, Zhenzhong


    Brain-derived neurotrophic factor (BDNF) is critical for sensory neuron survival and is necessary for vesicular glutamate transporter 3 (VGLUT3) expression. Whether the transcription factors Etv4 and Etv5 are involved in these BDNF-induced effects remains unclear. In the present study, primary cultured dorsal root ganglion (DRG) neurons were used to test the link between BDNF and transcription factors Etv4 and Etv5 on VGLUT3 expression and neurite outgrowth. BDNF promoted the mRNA and protein expression of Etv4 and Etv5 in DRG neurons. These effects were blocked by extracellular signal-regulated protein kinase 1/2 (ERK1/2) inhibitor PD98059 but not phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 or phospholipase C-γ (PLC-γ) inhibitor U73122. Etv4 siRNA and Etv5 siRNA effectively blocked the VGLUT3 expression and neurite elongation induced by BNDF. The overexpression of Etv4 or Etv5 potentiated the effects of BNDF-induced neurite elongation and growth-associated protein 43 (GAP-43), medium neurofilament (NF-M), and light neurofilament (NF-L) expression while these effects could be inhibited by Etv4 and Etv5 siRNA. These data imply that Etv4 and Etv5 are essential transcription factors in modulating BDNF/TrkB signaling-mediated VGLUT3 expression and neurite outgrowth. BDNF, through the ERK1/2 signaling pathway, activates Etv4 and Etv5 to initiate GAP-43 expression, promote neurofilament (NF) protein expression, induce neurite outgrowth, and mediate VGLUT3 expression for neuronal function improvement. The biological effects initiated by BDNF/TrkB signaling linked to E26 transformation-specific (ETS) transcription factors are important to elucidate neuronal differentiation, axonal regeneration, and repair in various pathological states.

  6. 2015年北京某医院神经科主诊医师组DRGs指标分析%DRG Index Analysis for Attending Neurologist Groups in a Hospital in 2015

    Institute of Scientific and Technical Information of China (English)

    李小莹; 仇叶龙; 冀冰心; 张艳红; 王力红


    目的 分析研究医院神经科部分主诊医师组的DRGs指标,发现优势与不足,为主诊医师绩效考核与管理提供建议.方法 以国家版DRGs(CN-DRGs)分组方式,运用病例组合指数、费用消耗指数、时间消耗指数等指标对2015年神经科脑血管病、癫痫、神经介入各主诊医师组进行分析.结果 神经介入主诊医师组的CMI最高,癫痫主诊医师组的CMI最低,全部主诊组的费用消耗指数均小于1,癫痫主诊组的时间消耗指数均超过1,介入主诊组的时间消耗指数最低,为0.5.结论 应用DRGs指标,评价各主诊医师组的住院绩效情况,可以客观、公平地评价其医疗能力与医疗效率,树立标杆,促进各主诊组竞争.%Objectives To analysis the DRG indicators for attending neurologist groups relevant sections in research hospital, discover the advantages and disadvantages to provide recommendations for the development of attending groups.Methods To analyze on patients discharged from the hospital with the application of case-mixindex (CMI), time-consuming index, cost-consuming index, as well as other indicators according to CN-DRG grouping packet mode, in neurological cerebrovascular disease, epilepsy, neuropathic involvement of each attending group. Results Neural involvement attending group's CMI was the highest, epilepsy attending group's CMI was the lowest. All of the attending groups cost-consumption index was less than 1, both the epilepsy attending groups time-consuming index was over 1, and involved attending groups time-consuming index was the lowest, which was 0.5.Conclusions Applications DRG indicators to evaluate inpatient performance situation of each attending group can objectively and fairly evaluate their medical capabilities and medical efficiency, establish a benchmark, promote the competition among each attending groups.

  7. TLR signaling adaptor protein MyD88 in primary sensory neurons contributes to persistent inflammatory and neuropathic pain and neuroinflammation (United States)

    Liu, Xing-Jun; Liu, Tong; Chen, Gang; Wang, Bing; Yu, Xiao-Lu; Yin, Cui; Ji, Ru-Rong


    Increasing evidence suggests that neuro-immune and neuro-glial interactions are critically involved in chronic pain sensitization. It is well studied how immune/glial mediators sensitize pain, but how sensory neurons control neuroinflammation remains unclear. We employed Myd88 conditional knockout (CKO) mice, in which Myd88 was deleted in sodium channel subunit Nav1.8-expressing primary sensory neurons, to examine the unique role of neuronal MyD88 in regulating acute and chronic pain, and possible underlying mechanisms. We found that baseline pain and the formalin induced acute inflammatory pain were intact in CKO mice. However, the late phase inflammatory pain following complete Freund’s adjuvant injection and the late phase neuropathic pain following chronic constriction injury (CCI), were reduced in CKO mice. CCI induced up-regulation of MyD88 and chemokine C-C motif ligand 2 expression in DRG neurons and macrophage infiltration into DRGs, and microglia activation in spinal dorsal horns in wild-type mice, but all these changes were compromised in CKO mice. Finally, the pain hypersensitivity induced by intraplantar IL-1β was reduced in CKO mice. Our findings suggest that MyD88 in primary sensory neurons plays an active role in regulating IL-1β signaling and neuroinflammation in the peripheral and the central nervous systems, and contributes to the maintenance of persistent pain. PMID:27312666

  8. Developmental localization of calcitonin gene-related peptide in dorsal sensory axons and ventral motor neurons of mouse cervical spinal cord. (United States)

    Kim, Jeongtae; Sunagawa, Masanobu; Kobayashi, Shiori; Shin, Taekyun; Takayama, Chitoshi


    Calcitonin gene-related peptide (CGRP) is a 37-amino-acid neuropeptide, synthesized by alternative splicing of calcitonin gene mRNA. CGRP is characteristically distributed in the nervous system, and its function varies depending on where it is expressed. To reveal developmental formation of the CGRP network and its function in neuronal maturation, we examined the immunohistochemical localization of CGRP in the developing mouse cervical spinal cord and dorsal root ganglion. CGRP immunolabeling (IL) was first detected in motor neurons on E13, and in ascending axons of the posterior funiculus and DRG neurons on E14. CGRP-positive sensory axon fibers entered Laminae I and II on E16, and Laminae I through IV on E18. The intensity of the CGRP-IL gradually increased in both ventral and dorsal horns during embryonic development, but markedly decreased in the ventral horn after birth. These results suggest that CGRP is expressed several days after neuronal settling and entry of sensory fibers, and that the CGRP network is formed in chronological and sequential order. Furthermore, because CGRP is markedly expressed in motor neurons when axons are vastly extending and innervating targets, CGRP may also be involved in axonal elongation and synapse formation during normal development.

  9. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri


    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  10. Motor neurone disease. (United States)


    Essential facts Motor neurone disease describes a group of related diseases, affecting the neurones in the brain and spinal cord. Progressive, incurable and life-limiting, MND is rare, with about 1,100 people developing it each year in the UK and up to 5,000 people affected at any one time. One third of people will die within a year of diagnosis and more than half within two years. About 5% to 10% are alive at ten years.

  11. Neuron division or enucleation. (United States)

    Sotnikov, O S; Laktionova, A A; Solovieva, I A; Krasnova, T V


    The classical Bielschowsky-Gross neurohistological method was used to reproduce all the morphological phenomena interpreted by many authors as signs of neuron division, budding, and fission. It is suggested that these signs are associated with the effects of enucleation, which occurs in many cells of other tissue types in response to a variety of chemical and physical treatments. Studies were performed using neurons isolated from the mollusk Lymnaea stagnalis and exposed in tissue culture to the actin microfilament inhibitor cytochalasin B. Phase contrast time-lapse video recording over periods of 4-8 h demonstrated nuclear displacement, ectopization, and budding, to the level of almost complete fission of the neuron body. This repeats the pattern seen in static fixed preparations in "normal" conditions and after different experimental treatments. Budding of the cytoplasm was also sometimes seen at the early stages of the experiments. Control experiments in which cultured neurons were exposed to the solvent for cytochalasin B, i.e., dimethylsulfoxide (DMSO), did not reveal any changes in neurons over a period of 8 h. We take the view that the picture previously interpreted as neuron division and fission can be explained in terms of the inhibition of actin microfilaments, sometimes developing spontaneously in cells undergoing individual metabolic changes preventing the maintenance of cytoskeleton stability.

  12. NeuronBank: A Tool for Cataloging Neuronal Circuitry. (United States)

    Katz, Paul S; Calin-Jageman, Robert; Dhawan, Akshaye; Frederick, Chad; Guo, Shuman; Dissanayaka, Rasanjalee; Hiremath, Naveen; Ma, Wenjun; Shen, Xiuyn; Wang, Hsui C; Yang, Hong; Prasad, Sushil; Sunderraman, Rajshekhar; Zhu, Ying


    The basic unit of any nervous system is the neuron. Therefore, understanding the operation of nervous systems ultimately requires an inventory of their constituent neurons and synaptic connectivity, which form neural circuits. The presence of uniquely identifiable neurons or classes of neurons in many invertebrates has facilitated the construction of cellular-level connectivity diagrams that can be generalized across individuals within a species. Homologous neurons can also be recognized across species. Here we describe, a web-based tool that we are developing for cataloging, searching, and analyzing neuronal circuitry within and across species. Information from a single species is represented in an individual branch of NeuronBank. Users can search within a branch or perform queries across branches to look for similarities in neuronal circuits across species. The branches allow for an extensible ontology so that additional characteristics can be added as knowledge grows. Each entry in NeuronBank generates a unique accession ID, allowing it to be easily cited. There is also an automatic link to a Wiki page allowing an encyclopedic explanation of the entry. All of the 44 previously published neurons plus one previously unpublished neuron from the mollusc, Tritonia diomedea, have been entered into a branch of NeuronBank as have 4 previously published neurons from the mollusc, Melibe leonina. The ability to organize information about neuronal circuits will make this information more accessible, ultimately aiding research on these important models.

  13. NeuronBank: a tool for cataloging neuronal circuitry

    Directory of Open Access Journals (Sweden)

    Paul S Katz


    Full Text Available The basic unit of any nervous system is the neuron. Therefore, understanding the operation of nervous systems ultimately requires an inventory of their constituent neurons and synaptic connectivity, which form neural circuits. The presence of uniquely identifiable neurons or classes of neurons in many invertebrates has facilitated the construction of cellular-level connectivity diagrams that can be generalized across individuals within a species. Homologous neurons can also be recognized across species. Here we describe, a web-based tool that we are developing for cataloging, searching, and analyzing neuronal circuitry within and across species. Information from a single species is represented in an individual branch of NeuronBank. Users can search within a branch or perform queries across branches to look for similarities in neuronal circuits across species. The branches allow for an extensible ontology so that additional characteristics can be added as knowledge grows. Each entry in NeuronBank generates a unique accession ID, allowing it to be easily cited. There is also an automatic link to a Wiki page allowing an encyclopedic explanation of the entry. All of the 44 previously published neurons plus one previously unpublished neuron from the mollusc, Tritonia diomedea, have been entered into a branch of NeuronBank as have 4 previously published neurons from the mollusc, Melibe leonina. The ability to organize information about neuronal circuits will make this information more accessible, ultimately aiding research on these important models.

  14. NeuronBank: A Tool for Cataloging Neuronal Circuitry (United States)

    Katz, Paul S.; Calin-Jageman, Robert; Dhawan, Akshaye; Frederick, Chad; Guo, Shuman; Dissanayaka, Rasanjalee; Hiremath, Naveen; Ma, Wenjun; Shen, Xiuyn; Wang, Hsui C.; Yang, Hong; Prasad, Sushil; Sunderraman, Rajshekhar; Zhu, Ying


    The basic unit of any nervous system is the neuron. Therefore, understanding the operation of nervous systems ultimately requires an inventory of their constituent neurons and synaptic connectivity, which form neural circuits. The presence of uniquely identifiable neurons or classes of neurons in many invertebrates has facilitated the construction of cellular-level connectivity diagrams that can be generalized across individuals within a species. Homologous neurons can also be recognized across species. Here we describe, a web-based tool that we are developing for cataloging, searching, and analyzing neuronal circuitry within and across species. Information from a single species is represented in an individual branch of NeuronBank. Users can search within a branch or perform queries across branches to look for similarities in neuronal circuits across species. The branches allow for an extensible ontology so that additional characteristics can be added as knowledge grows. Each entry in NeuronBank generates a unique accession ID, allowing it to be easily cited. There is also an automatic link to a Wiki page allowing an encyclopedic explanation of the entry. All of the 44 previously published neurons plus one previously unpublished neuron from the mollusc, Tritonia diomedea, have been entered into a branch of NeuronBank as have 4 previously published neurons from the mollusc, Melibe leonina. The ability to organize information about neuronal circuits will make this information more accessible, ultimately aiding research on these important models. PMID:20428500

  15. Laser fabricated discontinuous anisotropic microconical substrates as a new model scaffold to control the directionality of neuronal network outgrowth. (United States)

    Simitzi, C; Efstathopoulos, P; Kourgiantaki, A; Ranella, A; Charalampopoulos, I; Fotakis, C; Athanassakis, I; Stratakis, E; Gravanis, A


    Patterning of neuronal outgrowth in vitro is important in tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. To date, this has been achieved with the aid of micro- and nanofabrication techniques giving rise to various anisotropic topographies, either in the form of continuous or discontinuous structures. In this study we propose a currently unexplored geometry of a 3D culture substrate for neuronal cell growth comprising discontinuous subcellular microstructures with anisotropic geometrical cross-section. Specifically, using laser precision 3D micro/nano fabrication techniques, silicon substrates comprising arrays of parallel oriented elliptical microcones (MCs) were fabricated to investigate whether a discontinuous geometry comprising anisotropic features at the subcellular level could influence the alignment of peripheral nervous system cell populations. It was shown that both Schwann cells and axons of sympathetic neurons were parallel oriented onto the MCs of elliptical shape, while they exhibited a random orientation onto the MCs of arbitrary shape. Notably, this topography-induced guidance effect was also observed in more complex cell culture systems, such as the organotypic culture whole dorsal root ganglia (DRG) explants. Our results suggest that a discontinuous topographical pattern could promote Schwann cell and axonal alignment, provided that it hosts anisotropic geometrical features, even though the sizes of those range at the subcellular lengthscale. The laser-patterned arrays of MCs presented here could potentially be a useful platform for patterning neurons into artificial networks, allowing the study of neuronal cells interactions under 3D ex-vivo conditions.

  16. F-18 Polyethyleneglycol stilbenes as PET imaging agents targeting A{beta} aggregates in the brain

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wei [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Oya, Shunichi [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Kung Meiping [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Hou, Catherine [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Maier, Donna L. [Department of Neuroscience, AstraZeneca, Wilmington, DE 19850 (United States); Kung, Hank F. [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States) and Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104 (United States)]. E-mail:


    This paper describes a novel series of {sup 18}F-labeled polyethyleneglycol (PEG)-stilbene derivatives as potential {beta}-amyloid (A{beta}) plaque-specific imaging agents for positron emission tomography (PET). In these series of compounds, {sup 18}F is linked to the stilbene through a PEG chain, of which the number of ethoxy groups ranges from 2 to 5. The purpose of adding PEG groups is to lower the lipophilicity and improve bioavailability. The syntheses of the 'cold' compounds and the {sup 18}F-labeled PEG stilbene derivatives are successfully achieved. All of the fluorinated stilbenes displayed high binding affinities in an assay using postmortem AD brain homogenates (K {sub i}=2.9-6.7 nM). Labeling was successfully performed by a substitution of the mesylate group of 10a-d by [{sup 18}F]fluoride giving the target compounds [{sup 18}F]12a-d (EOS, specific activity, 900-1500 Ci/mmol; radiochemical purity >99%). In vivo biodistribution of these novel {sup 18}F ligands in normal mice exhibited excellent brain penetrations and rapid washouts after an intravenous injection (6.6-8.1 and 1.2-2.6% dose/g at 2 and 60 min, respectively). Autoradiography of postmortem AD brain sections of [{sup 18}F]12a-d confirmed the specific binding related to the presence of A{beta} plaques. In addition, in vivo plaque labeling can be clearly demonstrated with these {sup 18}F-labeled agents in transgenic mice (Tg2576), a useful animal model for Alzheimer's disease. In conclusion, the preliminary results strongly suggest these fluorinated PEG stilbene derivatives are suitable candidates as A{beta} plaque imaging agents for studying patients with Alzheimer's disease.

  17. Pain-related sensory innervation in monoiodoacetate-induced osteoarthritis in rat knees that gradually develops neuronal injury in addition to inflammatory pain

    Directory of Open Access Journals (Sweden)

    Toyone Tomoaki


    Full Text Available Abstract Background The exact mechanism of knee osteoarthritis (OA-associated pain is unclear, whereas mixed evidence of inflammatory pain and neuropathic pain has been noted. We aimed to investigate pain-related sensory innervation in a monoiodoacetate (MIA-induced model of OA. Methods Sixty of seventy female Sprague Dawley rats of six week-old underwent intra-articular MIA and fluorogold (FG retrograde neurotracer injection into their right (ipsilateral knee, while their left knees were treated with FG in saline as a control (contralateral knee. Other rats were treated with FG only bilaterally, and used as controls. Rats were evaluated for tactile allodynia using von Frey hairs. Proinflammatory mediators in the knee soft tissues, including tumor necrosis factor (TNF-α, interleukin (IL-6, and nerve growth factor (NGF, were quantified using ELISAs to evaluate inflammation in the knee after 1, 4, 7,14,21, and 28 days post injection:. Dorsal root ganglia (DRG were immunostained for three molecules after 7,14,21, and 28 days post injection: calcitonin gene-related peptide (CGRP, a marker of inflammatory pain; and activating transcription factor-3 (ATF3 and growth associated protein-43 (GAP43, as markers for nerve injury and regenerating axons. The distribution of microglia in the spinal cord were also evaluated, because they have been reported to increase in neuropathic pain states. These evaluations were performed up to 28 days postinjection. P Results Progressive tactile allodynia and elevated cytokine concentrations were observed in ipsilateral knees. CGRP-immunoreactive (-ir ipsilateral DRG neurons significantly increased, peaking at 14 days postinjection, while expression of FG-labeled ATF3-ir or ATF3-ir GAP43-ir DRG neurons significantly increased in a time-dependent manner. Significant proliferation of microglia were found with time in the ipsilateral dorsal horn. Conclusions Pain-related characteristics in a MIA-induced rat OA model can

  18. Neurons of human nucleus accumbens

    Directory of Open Access Journals (Sweden)

    Sazdanović Maja


    Full Text Available Background/Aim. Nucleus accumbens is a part of the ventral striatum also known as a drug active brain region, especially related with drug addiction. The aim of the study was to investigate the Golgi morphology of the nucleus accumbens neurons. Methods. The study was performed on the frontal and sagittal sections of 15 human brains by the Golgi Kopsch method. We classified neurons in the human nucleus accumbens according to their morphology and size into four types: type I - fusiform neurons; type II - fusiform neurons with lateral dendrite, arising from a part of the cell body; type III - pyramidal-like neuron; type IV - multipolar neuron. The medium spiny neurons, which are mostly noted regarding to the drug addictive conditions of the brain, correspond to the type IV - multipolar neurons. Results. Two regions of human nucleus accumbens could be clearly recognized on Nissl and Golgi preparations each containing different predominant neuronal types. Central part of nucleus accumbens, core region, has a low density of impregnated neurons with predominant type III, pyramidal-like neurons, with spines on secondary branches and rare type IV, multipolar neurons. Contrary to the core, peripheral region, shell of nucleus, has a high density of impregnated neurons predominantly contained of type I and type IV - multipolar neurons, which all are rich in spines on secondary and tertiary dendritic branches. Conclusion. Our results indicate great morphological variability of human nucleus accumbens neurons. This requires further investigations and clarifying clinical significance of this important brain region.

  19. APOE epsilon 4 influences the pathological phenotype of Alzheimer's disease by favouring cerebrovascular over parenchymal accumulation of A beta protein. (United States)

    Chalmers, K; Wilcock, G K; Love, S


    The relative amounts of amyloid beta-protein (A beta) in cerebral blood vessels and parenchyma vary considerably amongst patients with Alzheimer's disease (AD). Although several mechanisms have been proposed to explain this variability, the underlying genetic and environmental determinants are still unclear, as are the functional consequences. Polymorphisms in APOE, the gene for apolipoprotein E (ApoE), influence the risk of developing AD and of deposition of A beta within the brain. We examined the relationship between the APOE genotype and the relative extent of accumulation of A beta as plaques within the cerebral parenchyma and in cortical blood vessels in the form of cerebral amyloid angiopathy (CAA), in autopsy brain tissue from 125 AD cases and from 53 elderly, neurologically normal controls of which 19 had CAA without other neuropathological features of AD. In the AD cases, we also assessed whether the severity of CAA was related to the age of onset and duration of dementia, risk factors for atherosclerotic vascular disease, and histologically demonstrable cerebral infarcts or foci of haemorrhage. The APOE genotype was determined by a standard polymerase chain reaction-based method. Paraffin sections of frontal, temporal and parietal lobes were immunolabelled for A beta and the parenchymal A beta load (total A beta minus vessel-associated A beta) was quantified by computer-assisted image analysis. CAA severity was scored for cortical and leptomeningeal vessels. The relevant clinical data were obtained from the database of the South West Brain Bank. In AD, we found the severity of CAA to be strongly associated with the number of epsilon 4 alleles (P possession of the APOE epsilon 4 allele favours vascular over parenchymal accumulation of A beta in AD. This may influence the pathogenesis of neurodegeneration in epsilon 4-associated AD.

  20. Phosphate and HEPES buffers potently affect the fibrillation and oligomerization mechanism of Alzheimer's A{beta} peptide

    Energy Technology Data Exchange (ETDEWEB)

    Garvey, Megan; Tepper, Katharina [Max-Planck-Forschungsstelle fuer Enzymologie der Proteinfaltung, Weinbergweg 22, D-06120 Halle (Saale) (Germany); Haupt, Caroline [Institute fuer Physik, Biophysik, Martin-Luther Universitaet Halle-Wittenberg, Betty-Heimann-Str. 7, D-06120 Halle (Saale) (Germany); Knuepfer, Uwe [Leibniz-Institute for Infection Biology and Natural Product Research, Beutenbergstr. 11a, D-07745 Jena (Germany); Klement, Karolin; Meinhardt, Jessica [Leibniz-Institute for Age Research (FLI), Beutenbergstr. 11, D-07745 Jena (Germany); Horn, Uwe [Leibniz-Institute for Infection Biology and Natural Product Research, Beutenbergstr. 11a, D-07745 Jena (Germany); Balbach, Jochen [Institute fuer Physik, Biophysik, Martin-Luther Universitaet Halle-Wittenberg, Betty-Heimann-Str. 7, D-06120 Halle (Saale) (Germany); Faendrich, Marcus, E-mail: [Max-Planck-Forschungsstelle fuer Enzymologie der Proteinfaltung, Weinbergweg 22, D-06120 Halle (Saale) (Germany); Bio zentrum, Martin-Luther Universitaet Halle-Wittenberg, Weinbergweg 22, D-06120 Halle (Saale) (Germany)


    Highlights: {yields} Sodium phosphate buffer accelerated A{beta}(1-40) nucleation relative to HEPES. {yields} A{beta}(1-40) fibrils formed in the two buffers show only minor structural differences. {yields} NMR revealed that A{beta}(1-40) histidine residues mediate buffer dependent changes. -- Abstract: The oligomerization of A{beta} peptide into amyloid fibrils is a hallmark of Alzheimer's disease. Due to its biological relevance, phosphate is the most commonly used buffer system for studying the formation of A{beta} and other amyloid fibrils. Investigation into the characteristics and formation of amyloid fibrils frequently relies upon material formed in vitro, predominantly in phosphate buffers. Herein, we examine the effects on the fibrillation and oligomerization mechanism of A{beta} peptide that occur due solely to the influence of phosphate buffer. We reveal that significant differences in amyloid fibrillation are observed due to fibrillation being initiated in phosphate or HEPES buffer (at physiological pH and temperature). Except for the differing buffer ions, all experimental parameters were kept constant. Fibril formation was assessed using fluorescently monitored kinetic studies, microscopy, X-ray fiber diffraction and infrared and nuclear magnetic resonance spectroscopies. Based on this set up, we herein reveal profound effects on the mechanism and speed of A{beta} fibrillation. The three histidine residues at positions 6, 13 and 14 of A{beta}(1-40) are instrumental in these mechanistic changes. We conclude that buffer plays a more significant role in fibril formation than has been generally acknowledged.

  1. Neuronal survival in the brain: neuron type-specific mechanisms. (United States)

    Pfisterer, Ulrich; Khodosevich, Konstantin


    Neurogenic regions of mammalian brain produce many more neurons that will eventually survive and reach a mature stage. Developmental cell death affects both embryonically produced immature neurons and those immature neurons that are generated in regions of adult neurogenesis. Removal of substantial numbers of neurons that are not yet completely integrated into the local circuits helps to ensure that maturation and homeostatic function of neuronal networks in the brain proceed correctly. External signals from brain microenvironment together with intrinsic signaling pathways determine whether a particular neuron will die. To accommodate this signaling, immature neurons in the brain express a number of transmembrane factors as well as intracellular signaling molecules that will regulate the cell survival/death decision, and many of these factors cease being expressed upon neuronal maturation. Furthermore, pro-survival factors and intracellular responses depend on the type of neuron and region of the brain. Thus, in addition to some common neuronal pro-survival signaling, different types of neurons possess a variety of 'neuron type-specific' pro-survival constituents that might help them to adapt for survival in a certain brain region. This review focuses on how immature neurons survive during normal and impaired brain development, both in the embryonic/neonatal brain and in brain regions associated with adult neurogenesis, and emphasizes neuron type-specific mechanisms that help to survive for various types of immature neurons. Importantly, we mainly focus on in vivo data to describe neuronal survival specifically in the brain, without extrapolating data obtained in the PNS or spinal cord, and thus emphasize the influence of the complex brain environment on neuronal survival during development.

  2. Kappe neurons, a novel population of olfactory sensory neurons (United States)

    Ahuja, Gaurav; Nia, Shahrzad Bozorg; Zapilko, Veronika; Shiriagin, Vladimir; Kowatschew, Daniel; Oka, Yuichiro; Korsching, Sigrun I.


    Perception of olfactory stimuli is mediated by distinct populations of olfactory sensory neurons, each with a characteristic set of morphological as well as functional parameters. Beyond two large populations of ciliated and microvillous neurons, a third population, crypt neurons, has been identified in teleost and cartilaginous fishes. We report here a novel, fourth olfactory sensory neuron population in zebrafish, which we named kappe neurons for their characteristic shape. Kappe neurons are identified by their Go-like immunoreactivity, and show a distinct spatial distribution within the olfactory epithelium, similar to, but significantly different from that of crypt neurons. Furthermore, kappe neurons project to a single identified target glomerulus within the olfactory bulb, mdg5 of the mediodorsal cluster, whereas crypt neurons are known to project exclusively to the mdg2 glomerulus. Kappe neurons are negative for established markers of ciliated, microvillous and crypt neurons, but appear to have microvilli. Kappe neurons constitute the fourth type of olfactory sensory neurons reported in teleost fishes and their existence suggests that encoding of olfactory stimuli may require a higher complexity than hitherto assumed already in the peripheral olfactory system.

  3. Stochastic neuron models

    CERN Document Server

    Greenwood, Priscilla E


    This book describes a large number of open problems in the theory of stochastic neural systems, with the aim of enticing probabilists to work on them. This includes problems arising from stochastic models of individual neurons as well as those arising from stochastic models of the activities of small and large networks of interconnected neurons. The necessary neuroscience background to these problems is outlined within the text, so readers can grasp the context in which they arise. This book will be useful for graduate students and instructors providing material and references for applying probability to stochastic neuron modeling. Methods and results are presented, but the emphasis is on questions where additional stochastic analysis may contribute neuroscience insight. An extensive bibliography is included. Dr. Priscilla E. Greenwood is a Professor Emerita in the Department of Mathematics at the University of British Columbia. Dr. Lawrence M. Ward is a Professor in the Department of Psychology and the Brain...

  4. Neuronal survival in the brain: neuron type-specific mechanisms

    DEFF Research Database (Denmark)

    Pfisterer, Ulrich Gottfried; Khodosevich, Konstantin


    Neurogenic regions of mammalian brain produce many more neurons that will eventually survive and reach a mature stage. Developmental cell death affects both embryonically produced immature neurons and those immature neurons that are generated in regions of adult neurogenesis. Removal of substantial...... a particular neuron will die. To accommodate this signaling, immature neurons in the brain express a number of transmembrane factors as well as intracellular signaling molecules that will regulate the cell survival/death decision, and many of these factors cease being expressed upon neuronal maturation...... numbers of neurons that are not yet completely integrated into the local circuits helps to ensure that maturation and homeostatic function of neuronal networks in the brain proceed correctly. External signals from brain microenvironment together with intrinsic signaling pathways determine whether...

  5. Aluminum modulates effects of beta amyloid(1-42) on neuronal calcium homeostasis and mitochondria functioning and is altered in a triple transgenic mouse model of Alzheimer's disease. (United States)

    Drago, Denise; Cavaliere, Alessandra; Mascetra, Nicola; Ciavardelli, Domenico; di Ilio, Carmine; Zatta, Paolo; Sensi, Stefano L


    Recent findings suggest that beta-amyloid (A beta) is more neurotoxic when present in its oligomeric configuration rather than as monomers or fibrils. Previous work from our laboratories has shown that A beta aggregation is strongly influenced by the conjugation of the peptide with metal ions (aluminum A, copper [Cu], zinc [Zn], and iron [Fe]) that are found in high concentrations in the core of senile plaques. Disruption of Ca++ signaling and mitochondrial dysfunction are potent triggers of neuronal death and have been implicated in the neuronal loss that is associated with Alzheimer's disease (AD). In this study, we explored whether A beta-metal complexes can have detrimental effects on intraneuronal Ca++ ([Ca++]i) homeostasis and mitochondrial function in vitro. Results from our experiments indicate that, when conjugated with Al, A beta perturbs neuronal [Ca++]i homeostasis and inhibits mitochondrial respiration. Finally, we analyzed the content of the four metals in the brain of a triple transgenic animal model of AD and found that Al is the only one to be increased in the cortex of these mice.

  6. Nanoresolution radiology of neurons

    Energy Technology Data Exchange (ETDEWEB)

    Wu, H.R.; Chen, S.T.; Chu, Y.S.; Conley, R.; Bouet, N.; Chien, C.C.; Chen, H.H.; Lin, C.H.; Tung, H.T.; Chen, Y.S.; Margaritondo, G.; Je, J.H.; Hwu, Y. (IP-Taiwan); (Ecole); (BNL); (POSTECH)


    We report recent advances in hard-x-ray optics - including record spatial resolution - and in staining techniques that enable synchrotron microradiology to produce neurobiology images of quality comparable to electron and visible microscopy. In addition, microradiology offers excellent penetration and effective three-dimensional detection as required for many neuron studies. Our tests include tomographic reconstruction based on projection image sets.

  7. Exploring neuronal activity with photons (United States)

    Bourdieu, Laurent; Léger, Jean-François


    The following sections are included: * Introduction * Information coding * Optical recordings of neuronal activity * Functional organization of the cortex at the level of a cortical column * Microarchitecture of a cortical column * Dynamics of neuronal populations * Outlook * Bibliography

  8. New findings on neuron development

    Institute of Scientific and Technical Information of China (English)


    @@ A mature neuron receives inputs from multiple dendrites and sends its output to other neurons via a single axon.This polarized morphology requires proper axonal/dendritic differentiation during development.

  9. Binary neuron with optical devices (United States)

    Degeratu, Vasile; Degeratu, Ştefania; Şchiopu, Paul; Şchiopu, Carmen


    In this paper the authors present a model of binary neuron, a model of McCulloch-Pitts neuron with optical devices. This model of neuron can be implemented not only in the optic integrated circuits but also in the classic optical circuits it being cheap and immune not only into electromagnetic fields but also into any kind of radiation. The transfer speed of information through the neuron is very higher, it being limited only by the light speed from the received medium.

  10. Development of a DSP-based real-time position calculation circuit for a beta camera

    CERN Document Server

    Yamamoto, S; Kanno, I


    A digital signal processor (DSP)-based position calculation circuit was developed and tested for a beta camera. The previous position calculation circuit which employed flash analog-to-digital (A-D) converters for A-D conversion and ratio calculation produced significant line artifacts in the image due to the differential non-linearity of the A-D converters. The new position calculation circuit uses four A-D converters for A-D conversion of the analog signals from the position sensitive photomultiplier tube (PSPMT). The DSP reads the A-D signals and calculates the ratio of X sub a /(X sub a +X sub b) and Y sub a /(Y sub a +Y sub b) on an event-by-event basis. The DSP also magnifies the image to fit the useful field of view (FOV) and rejects the events out of the FOV. The line artifacts in the image were almost eliminated.

  11. Dispersive waves induced by self-defocusing temporal solitons in a beta-barium-borate crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Bache, Morten


    We experimentally observe dispersive waves in the anomalous dispersion regime of a beta-barium-borate (BBO) crystal, induced by a self-defocusing few-cycle temporal soliton. Together the soliton and dispersive waves form an energetic octave-spanning supercontinuum. The soliton was excited...... in the normal dispersion regime of BBO through a negative cascaded quadratic nonlinearity. Using pump wavelengths from 1.24 to 1.4 μm, dispersive waves are found from 1.9 to 2.2 μm, agreeing well with calculated resonant phasematching wavelengths due to degenerate four-wave mixing to the soliton. We also...... observe resonant radiation from nondegenerate four-wave mixing between the soliton and a probe wave, which was formed by leaking part of the pump spectrum into the anomalous dispersion regime. We confirm the experimental results through simulations....

  12. Dispersive waves induced by self-defocusing temporal solitons in a beta-barium-borate crystal. (United States)

    Zhou, Binbin; Bache, Morten


    We experimentally observe dispersive waves in the anomalous dispersion regime of a beta-barium-borate (BBO) crystal, induced by a self-defocusing few-cycle temporal soliton. Together the soliton and dispersive waves form an energetic octave-spanning supercontinuum. The soliton was excited in the normal dispersion regime of BBO through a negative cascaded quadratic nonlinearity. Using pump wavelengths from 1.24 to 1.4 μm, dispersive waves are found from 1.9 to 2.2 μm, agreeing well with calculated resonant phase-matching wavelengths due to degenerate four-wave mixing to the soliton. We also observe resonant radiation from nondegenerate four-wave mixing between the soliton and a probe wave, which was formed by leaking part of the pump spectrum into the anomalous dispersion regime. We confirm the experimental results through simulations.

  13. Nav1.7 is the predominant sodium channel in rodent olfactory sensory neurons

    Directory of Open Access Journals (Sweden)

    Black Joel A


    Full Text Available Abstract Background Voltage-gated sodium channel Nav1.7 is preferentially expressed in dorsal root ganglion (DRG and sympathetic neurons within the peripheral nervous system. Homozygous or compound heterozygous loss-of-function mutations in SCN9A, the gene which encodes Nav1.7, cause congenital insensitivity to pain (CIP accompanied by anosmia. Global knock-out of Nav1.7 in mice is neonatal lethal reportedly from starvation, suggesting anosmia. These findings led us to hypothesize that Nav1.7 is the main sodium channel in the peripheral olfactory sensory neurons (OSN, also known as olfactory receptor neurons. Methods We used multiplex PCR-restriction enzyme polymorphism, in situ hybridization and immunohistochemistry to determine the identity of sodium channels in rodent OSNs. Results We show here that Nav1.7 is the predominant sodium channel transcript, with low abundance of other sodium channel transcripts, in olfactory epithelium from rat and mouse. Our in situ hybridization data show that Nav1.7 transcripts are present in rat OSNs. Immunostaining of Nav1.7 and Nav1.6 channels in rat shows a complementary accumulation pattern with Nav1.7 in peripheral presynaptic OSN axons, and Nav1.6 primarily in postsynaptic cells and their dendrites in the glomeruli of the olfactory bulb within the central nervous system. Conclusions Our data show that Nav1.7 is the dominant sodium channel in rat and mouse OSN, and may explain anosmia in Nav1.7 null mouse and patients with Nav1.7-related CIP.

  14. Modulation of action potential and calcium signaling by levetiracetam in rat sensory neurons. (United States)

    Ozcan, Mete; Ayar, Ahmet


    Levetiracetam (LEV), a new anticonvulsant agent primarily used to treat epilepsy, has been used in pain treatment but the cellular mechanism of this action remains unclear. This study aimed to investigate effects of LEV on the excitability and membrane depolarization-induced calcium signaling in isolated rat sensory neurons using the whole-cell patch clamp and fura 2-based ratiometric Ca(2+)-imaging techniques. Dorsal root ganglia (DRG) were excised from neonatal rats, and cultured following enzymatic and mechanical dissociation. Under current clamp conditions, acute application of LEV (30 µM, 100 µM and 300 µM) significantly increased input resistance and caused the membrane to hyperpolarize from resting membrane potential in a dose-dependent manner. Reversal potentials of action potential (AP) after hyperpolarising amplitudes were shifted to more negative, toward to potassium equilibrium potentials, after application of LEV. It also caused a decrease in number of APs in neurons fired multiple APs in response to prolonged depolarization. Fura-2 fluorescence Ca(2+) imaging protocols revealed that HiK(+) (30 mM)-induced intracellular free Ca(2+) ([Ca(2+)](i)) was inhibited to 97.8 ± 4.6% (n = 17), 92.6 ± 4.8% (n = 17, p < 0.01) and 89.1 ± 5.1% (n = 18, p < 0.01) after application of 30 µM, 100 µM and 300 µM LEV (respectively), without any significant effect on basal levels of [Ca(2+)](i). This is the first evidence for the effect of LEV on the excitability of rat sensory neurons through an effect which might involve activation of potassium channels and inhibition of entry of Ca(2+), providing new insights for cellular mechanism(s) of LEV in pain treatment modalities.

  15. Rhythm dynamics of complex neuronal networks with mixed bursting neurons

    Institute of Scientific and Technical Information of China (English)

    Lü Yong-Bing; Shi Xia; Zheng Yan-Hong


    The spatiotemporal order and rhythm dynamics of a complex neuronal network with mixed bursting neurons are studied in this paper.A quantitative characteristic,the width factor,is introduced to describe the rhythm dynamics of an individual neuron,and the average width factor is used to characterize the rhythm dynamics of a neuronal network.An r parameter is introduced to denote the ratio of the short bursting neurons in the network.Then we investigate the effect of the ratio on the rhythm dynamics of the neuronal network.The critical value of r is derived,and the neurons in the network always remain short bursting when the r ratio is larger than the critical value.

  16. Effects of BmKNJX11, a bioactive polypeptide purified from Buthus martensi Karsch, on sodium channels in rat dorsal root ganglion neurons. (United States)

    Wang, Xi-Jie; An, Shan-Shan; Cheng, Hong; Xu, San-Hua; Cheng, Jie; Lu, Wei; Gao, Rong; Xiao, Hang


    A long-chain polypeptide BmKNJX11 was purified from the venom of Asian scorpion Buthus martensi Karsch (BmK) by a combination of gel filtration, ion-exchange chromatography, and reverse-phase high-performance liquid chromatography. The molecular mass was found to be 7036.85 Da by electrospray ionization mass spectrometry. The first 15 N-terminal amino acid sequence of BmKNJX11 was determined to be GRDAY IADSE NCTYT by Edman degradation. With whole cell recording, BmKNJX11 inhibited tetrodotoxin-sensitive voltage-gated sodium channels (TTX-S VGSC) in freshly isolated rat dorsal root ganglion (DRG) neurons in a concentration- and voltage-dependent manner. At a concentration of 40 mug/ml BmKNJX11 lowered the activation threshold and produced negative shifting of TTX-S sodium current (I(Na)) activation curve. In addition, BmKNJX11 induced shifting of the steady-state inactivation curve to the left, delayed the recovery of TTX-S I(Na) from inactivation, and also reduced the fraction of available sodium channels. These results suggested that BmKNJX11 might exert effects on VGSC by binding to a specific site. Considering that TTX-S VGSC expressed in DRG neurons play a critical role in nociceptive transmission, the interaction of BmKNJX11 with TTX-S VGSC might lead to a change in excitability of nociceptive afferent fibers, which may be involved in the observed peripheral pain expression.

  17. Neuronal synchrony 


    Buzsáki, Gyorgy


    1. Neuronal synchrony: metabolic and wiring costs of excitatory and inhibitory systems The major part of the brain’s energy budget (~ 60-80%) is devoted to its communication activities. While inhibition is critical to brain function, relatively little attention has been paid to its metabolic costs. Understanding how inhibitory interneurons contribute to brain energy consumption (brain work) is not only of interest in understanding a fundamental aspect of brain function but also in understandi...

  18. Mesenchymal stem cells in a polycaprolactone conduit promote sciatic nerve regeneration and sensory neuron survival after nerve injury. (United States)

    Frattini, Flávia; Lopes, Fatima Rosalina Pereira; Almeida, Fernanda Martins; Rodrigues, Rafaela Fintelman; Boldrini, Leonardo Cunha; Tomaz, Marcelo A; Baptista, Abrahão Fontes; Melo, Paulo A; Martinez, Ana Maria Blanco


    Despite the fact that the peripheral nervous system is able to regenerate after traumatic injury, the functional outcomes following damage are limited and poor. Bone marrow mesenchymal stem cells (MSCs) are multipotent cells that have been used in studies of peripheral nerve regeneration and have yielded promising results. The aim of this study was to evaluate sciatic nerve regeneration and neuronal survival in mice after nerve transection followed by MSC treatment into a polycaprolactone (PCL) nerve guide. The left sciatic nerve of C57BL/6 mice was transected and the nerve stumps were placed into a biodegradable PCL tube leaving a 3-mm gap between them; the tube was filled with MSCs obtained from GFP+ animals (MSC-treated group) or with a culture medium (Dulbecco's modified Eagle's medium group). Motor function was analyzed according to the sciatic functional index (SFI). After 6 weeks, animals were euthanized, and the regenerated sciatic nerve, the dorsal root ganglion (DRG), the spinal cord, and the gastrocnemius muscle were collected and processed for light and electron microscopy. A quantitative analysis of regenerated nerves showed a significant increase in the number of myelinated fibers in the group that received, within the nerve guide, stem cells. The number of neurons in the DRG was significantly higher in the MSC-treated group, while there was no difference in the number of motor neurons in the spinal cord. We also found higher values of trophic factors expression in MSC-treated groups, especially a nerve growth factor. The SFI revealed a significant improvement in the MSC-treated group. The gastrocnemius muscle showed an increase in weight and in the levels of creatine phosphokinase enzyme, suggesting an improvement of reinnervation and activity in animals that received MSCs. Immunohistochemistry documented that some GFP+ -transplanted cells assumed a Schwann-cell-like phenotype, as evidenced by their expression of the S-100 protein, a Schwann cell

  19. Micropatterning neuronal networks. (United States)

    Hardelauf, Heike; Waide, Sarah; Sisnaiske, Julia; Jacob, Peter; Hausherr, Vanessa; Schöbel, Nicole; Janasek, Dirk; van Thriel, Christoph; West, Jonathan


    Spatially organised neuronal networks have wide reaching applications, including fundamental research, toxicology testing, pharmaceutical screening and the realisation of neuronal implant interfaces. Despite the large number of methods catalogued in the literature there remains the need to identify a method that delivers high pattern compliance, long-term stability and is widely accessible to neuroscientists. In this comparative study, aminated (polylysine/polyornithine and aminosilanes) and cytophobic (poly(ethylene glycol) (PEG) and methylated) material contrasts were evaluated. Backfilling plasma stencilled PEGylated substrates with polylysine does not produce good material contrasts, whereas polylysine patterned on methylated substrates becomes mobilised by agents in the cell culture media which results in rapid pattern decay. Aminosilanes, polylysine substitutes, are prone to hydrolysis and the chemistries prove challenging to master. Instead, the stable coupling between polylysine and PLL-g-PEG can be exploited: Microcontact printing polylysine onto a PLL-g-PEG coated glass substrate provides a simple means to produce microstructured networks of primary neurons that have superior pattern compliance during long term (>1 month) culture.

  20. The same DRG cells innervate bladder and cervix simultaneouly in rats%大鼠膀胱与宫颈神经生理的解剖学探讨

    Institute of Scientific and Technical Information of China (English)

    陈天明; 熊恩庆; 宋波


    目的 探讨宫颈与膀胱之间的神经分布联系.方法 采用荧光素逆行双标法进行研究.健康成年雌性大鼠17只,随机分为实验组(12只)和对照组(5只),实验组将荧光素碘化丙啶(Propidium Iodide,PI)注入宫颈右侧壁肌层,双本甲亚胺(Bis-benzimde,Bb)注入膀胱右侧壁肌层内,对脊髓T13~S4节段进行追踪.结果 在实验组右侧L~S和L1~L的背根神经节(dorsal root ganglia,DRG)中发现荧光素双标细胞,对照组无双标细胞.结论 大鼠腰骶部L~S和L1~L节段的细胞周围突有分支同时投射到直肠和膀胱,说明宫颈炎性刺激引起的排尿异常机制可能与发生在DRG水平的寒触反射有关.

  1. Sensitization of voltage activated calcium channel currents for capsaicin in nociceptive neurons by tumor-necrosis-factor-alpha. (United States)

    Hagenacker, T; Czeschik, J C; Schäfers, M; Büsselberg, D


    It is known that application of tumor-necrosis-factor-alpha (TNF-alpha) sensitizes neuronal calcium channels for heat stimuli in rat models of neuropathic pain. This study examines whether TNF-alpha modulates the capsaicin-induced effects after transient receptor potential vanilloid (TRPV)-1 receptor activation on voltage activated calcium channel currents (I(Ca(V))). TRPV-1 receptors are activated by heat and play an important role in the pathogenesis of thermal hyperalgesia in neuropathic pain syndromes, while voltage activated channels are essential for transmission of neuronal signals. Eliciting I(Ca(V)) in DRG neurons of rats by a depolarization from the resting potential to 0 mV, TNF-alpha (100 ng/ml) reduces I(Ca(V)) by 16.9+/-2.2%, while capsaicin (0.1 microM) decreases currents by 27+/-4.3%. Pre-application of TNF-alpha (100 ng/ml) for 24h results in a sensitization of I(Ca(V)) to capsaicin (0.1 microM) with a reduction of 42.8+/-4.4% mediated by TRPV-1. While L-type (36.6+/-5.2%) and P/Q-type currents (35.6+/-4.1%) are also sensitized by TRPV-1 activation, N-type channel currents are most sensitive (74.5+/-7.3%). The capsaicin-induced shift towards the hyperpolarizing voltage range does not occur when TNF-alpha is applied. Summarizing, TNF-alpha sensitizes nociceptive neurons for capsaicin.

  2. Molecular characterization of a carbapenem-hydrolyzing class A beta-lactamase, SFC-1, from Serratia fonticola UTAD54. (United States)

    Henriques, Isabel; Moura, Alexandra; Alves, Artur; Saavedra, Maria José; Correia, António


    An environmental isolate of Serratia fonticola resistant to carbapenems contains a gene encoding a class A beta-lactamase with carbapenemase activity. The enzyme was designated SFC-1. The bla(SFC-I) gene is contained in the chromosome of S. fonticola UTAD54 and is absent from other S. fonticola strains.

  3. Peripheral sensory neuron injury contributes to neuropathic pain in experimental autoimmune encephalomyelitis (United States)

    Wang, I-Ching; Chung, Chen-Yen; Liao, Fang; Chen, Chih-Cheng; Lee, Cheng-Han


    Multiple sclerosis (MS)-induced neuropathic pain deteriorates quality of life in patients but is often refractory to treatment. In experimental autoimmune encephalomyelitis (EAE), a rodent model of MS, animals develop neuropathy and inflammation-induced tissue acidosis, which suggests the involvement of acid-sensing ion channels (ASICs). Also, peripheral neuropathy is reported in MS patients. However, the involvement of the peripheral nervous system (PNS) in MS neuropathic pain remains elusive. This study investigated the contribution of ASICs and peripheral neuropathy in MS-induced neuropathic pain. Elicited pain levels were as high in Asic1a−/−, Asic2−/− and Asic3−/− mice as wild-type mice even though only Asic1a−/− mice showed reduced EAE disease severity, which indicates that pain in EAE was independent of disease severity. We thus adopted an EAE model without pertussis toxin (EAEnp) to restrain activated immunity in the periphery and evaluate the PNS contribution to pain. Both EAE and EAEnp mice showed similar pain behaviors and peripheral neuropathy in nerve fibers and DRG neurons. Moreover, pregabalin significantly reduced neuropathic pain in both EAE and EAEnp mice. Our findings highlight the essential role of the PNS in neuropathic pain in EAE and pave the way for future development of analgesics without side effects in the CNS. PMID:28181561

  4. Amino acid residues that contribute to substrate specificity of class A beta-lactamase SME-1. (United States)

    Majiduddin, Fahd K; Palzkill, Timothy


    Carbapenem antibiotics are used as antibiotics of last resort because they possess a broad spectrum of antimicrobial activity and are not easily hydrolyzed by beta-lactamases. Recently, class A enzymes, such as the SME-1, NMC-A, and IMI-1 beta-lactamases, have been identified with the capacity to hydrolyze carbapenem antibiotics. Traditional class A beta-lactamases, such as TEM-1 and SHV-1, are unable to hydrolyze carbapenem antibiotics and exhibit some differences in sequence from those that are able to hydrolyze carbapenem antibiotics. The positions that differ may contribute to the unique substrate specificity of the class A carbapenemase SME-1. Codons in the SME-1 gene representing residues 104, 105, 132, 167, 237, and 241 were randomized by site-directed mutagenesis, and functional mutants were selected for the ability to hydrolyze imipenem, ampicillin, or cefotaxime. Although several positions are important for hydrolysis of beta-lactam antibiotics, no single position was found to uniquely contribute to carbapenem hydrolysis. The results of this study support a model whereby the carbapenemase activity of SME-1 is due to a highly distributed set of interactions that subtly alter the structure of the active-site pocket.

  5. A beta ray spectrometer based on a two-, or three-element silicon detector coincidence telescope

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Y.S.; Weizman, Y. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Physics; Hirning, C.R. [Ontario Hydro, Whitby, ON (Canada). Health Physics Dept.


    The operation of a beta ray energy spectrometer based on a two-or three-element silicon detector telescope is described. The front detector (A) is a thin, totally depleted, silicon surface barrier detector either 40 {mu}m, 72 {mu}m or 98 {mu}m thick. The back detector (C) is a Li compensated silicon detector, 5000 {mu}m thick. An additional thin detector can be inserted between these two detectors when additional photon rejection capability is required in intense photon fields. The capability of the spectrometer to reject photons is based on the fact that incident photons will have a small probability of simultaneously losing detectable energy in two detectors and an even smaller probability of losing detectable energy in all three detectors. Electrons, however, above a low energy threshold, will always record simultaneous, events in all three detectors. The spectrometer is capable of measuring electron energies from a lower energy coincidence threshold of 70 keV with 60% efficiency increasing to 100% efficiency in the energy region between 150 keV and 2.5 MeV. (Author).

  6. Development of a DSP-based real-time position calculation circuit for a beta camera

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi E-mail:; Matsuda, Tadashige; Kanno, Iwao


    A digital signal processor (DSP)-based position calculation circuit was developed and tested for a beta camera. The previous position calculation circuit which employed flash analog-to-digital (A-D) converters for A-D conversion and ratio calculation produced significant line artifacts in the image due to the differential non-linearity of the A-D converters. The new position calculation circuit uses four A-D converters for A-D conversion of the analog signals from the position sensitive photomultiplier tube (PSPMT). The DSP reads the A-D signals and calculates the ratio of X{sub a}/(X{sub a}+X{sub b}) and Y{sub a}/(Y{sub a}+Y{sub b}) on an event-by-event basis. The DSP also magnifies the image to fit the useful field of view (FOV) and rejects the events out of the FOV. The line artifacts in the image were almost eliminated.

  7. Modelling of Sigma Scorpii, a high-mass binary with a Beta Cep variable primary component

    CERN Document Server

    Tkachenko, A; Pavlovski, K; Degroote, P; Papics, P I; Moravveji, E; Lehmann, H; Kolbas, V; Clemer, K


    High-mass binary stars are known to show an unexplained discrepancy between the dynamical masses of the individual components and those predicted by models. In this work, we study Sigma Scorpii, a double-lined spectroscopic binary system consisting of two B-type stars residing in an eccentric orbit. The more massive primary component is a Beta Cep-type pulsating variable star. Our analysis is based on a time-series of some 1000 high-resolution spectra collected with the CORALIE spectrograph in 2006, 2007, and 2008. We use two different approaches to determine the orbital parameters of the star; the spectral disentangling technique is used to separate the spectral contributions of the individual components in the composite spectra. The non-LTE based spectrum analysis of the disentangled spectra reveals two stars of similar spectral type and atmospheric chemical composition. Combined with the orbital inclination angle estimate found in the literature, our orbital elements allow a mass estimate of 14.7 +/- 4.5 a...

  8. Frequency of the Group A Beta Hemolytic Streptococcus Infection in Children Presenting with Acute Tonsillopharyngitis

    Directory of Open Access Journals (Sweden)

    Özgül Yiğit


    Full Text Available Aim: The aim of this study was to evaluate the frequency of group A beta hemolytic streptococcus (GABHS in children with tonsillopharyngitis and to assess their complaints and clinical findings.Materials and Method: A total of 420 children who presented to our outpatient department with acute tonsillopharyngitis were enrolled to the study. The clinical features of patients with positive throat cultures for GABHS were compared to those with negative culture results. Presence of fever (≥37.50C, axilary, vomiting, coryza, sore throat, cough, abdominal pain, tenderness of cervical lymph nodes, and tonsillopharyngitis were recorded. Results: The mean age of the patients was 6.5±3.4 years (range, 1 to 14 years. The positive throat culture rate for GABHS was 22.62% (95 of 420 patients. It was found that fever, sore throat, cough, abdominal pain and tender cervical lymph nodes were significantly more frequent in patients with positive throat culture for GABHS than those with negative result for GABHS.Conclusion: GABHS should be firstly considered in patients presenting with symptoms of fever, sore throat, cough, abdominal pain and tenderness of cervical lymph nodes. (Journal of Current Pediatrics 2009; 7: 13-7

  9. Interactions of neurons with topographic nano cues affect branching morphology mimicking neuron-neuron interactions. (United States)

    Baranes, Koby; Kollmar, Davida; Chejanovsky, Nathan; Sharoni, Amos; Shefi, Orit


    We study the effect of topographic nano-cues on neuronal growth-morphology using invertebrate neurons in culture. We use photolithography to fabricate substrates with repeatable line-pattern ridges of nano-scale heights of 10-150 nm. We plate leech neurons atop the patterned-substrates and compare their growth pattern to neurons plated atop non-patterned substrates. The model system allows us the analysis of single neurite-single ridge interactions. The use of high resolution electron microscopy reveals small filopodia processes that attach to the line-pattern ridges. These fine processes, that cannot be detected in light microscopy, add anchoring sites onto the side of the ridges, thus additional physical support. These interactions of the neuronal process dominantly affect the neuronal growth direction. We analyze the response of the entire neuronal branching tree to the patterned substrates and find significant effect on the growth patterns compared to non-patterned substrates. Moreover, interactions with the nano-cues trigger a growth strategy similarly to interactions with other neuronal cells, as reflected in their morphometric parameters. The number of branches and the number of neurites originating from the soma decrease following the interaction demonstrating a tendency to a more simplified neuronal branching tree. The effect of the nano-cues on the neuronal function deserves further investigation and will strengthen our understanding of the interplay between function and form.

  10. From Neurons to Newtons

    DEFF Research Database (Denmark)

    Nielsen, Bjørn Gilbert


    network scripting language for specifying arbitrary neural architectures, de¯nition ¯les for detailed spinal networks, various biologically realistic models of neurons, and dynamic synapses. Also included are structurally accurate models of intrafusal and extra-fusal muscle ¯bers and a general body...... of phenomena, ranging from the force-velocity and force-length relationships, to tetanic fusion, "catch-like" e®ects and the distinctions between fast and slow muscle ¯ber types. Furthermore the model incorporates su±cient neuromus-cular information as to permit orderly recruitment of motor units, exponential...

  11. Molecular mechanism for opioid dichotomy: bidirectional effect of μ-opioid receptors on P2X₃ receptor currents in rat sensory neurones. (United States)

    Chizhmakov, Igor; Kulyk, Vyacheslav; Khasabova, Iryna; Khasabov, Sergey; Simone, Donald; Bakalkin, Georgy; Gordienko, Dmitri; Verkhratsky, Alexei; Krishtal, Oleg


    Here, we describe a molecular switch associated with opioid receptors-linked signalling cascades that provides a dual opioid control over P2X3 purinoceptor in sensory neurones. Leu-enkephalin inhibited P2X3-mediated currents with IC50 ~10 nM in ~25% of small nociceptive rat dorsal root ganglion (DRG) neurones. In contrast, in neurones pretreated with pertussis toxin leu-enkephalin produced stable and significant increase of P2X3 currents. All effects of opioid were abolished by selective μ-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), nonselective inhibitor naloxone, and by PLC inhibitor U73122. Thus, we discovered a dual link between purinoceptors and μ-opioid receptors: the latter exert both inhibitory (pertussis toxin-sensitive) and stimulatory (pertussis toxin-insensitive) actions on P2X3 receptors through phospholipase C (PLC)-dependent pathways. This dual opioid control of P2X3 receptors may provide a molecular explanation for dichotomy of opioid therapy. Pharmacological control of this newly identified facilitation/inhibition switch may open new perspectives for the adequate medical use of opioids, the most powerful pain-killing agents known today.

  12. 苯佐卡因对大鼠背根神经节神经元河豚毒素不敏感型钠离子通道的影响%Effects of benzocaine on tetrodotoxin-resistant sodium channels in rat dorsal root ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    章艳; 陈少锐; 贾岩岩; 刘培庆; 蒋建敏


    目的 研究苯佐卡因(BZC)对大鼠背根神经节(DRG)神经元河豚毒素不敏感型(TTX-r)钠电流的影响,探讨其镇痛作用的机制.方法 酶解法分离新生大鼠单个DRG神经元,应用全细胞膜片钳技术记录不同浓度BZC对TTX-r钠电流的影响.结果 BZC浓度依赖性静息阻断TTX-r钠电流,30、100和300 μmol·L-1的BZC分别使TTX-r钠电流峰值抑制率达(18.83 ± 8.51)%、(33.08 ± 9.19)%、(58.91 ± 12.02)%,并使TTX-r钠电流稳态失活曲线浓度依赖性向超极化方向移动.结论 BZC浓度依赖性阻断DRG神经元TTX-r钠离子通道并改变通道的失活,可能是其影响痛觉传导通路以及产生镇痛作用的机制之一.%Aim To investigate the effects of benzo-caine ( BZC ) on tetrodotoxin-resistant ( TTX-r ) Na+ currents in the rat dorsal root ganglion ( DRG ) neurons. Methods Neonatal rat DRG cells were isolated and the effects of BZC on TTX-r Na + currents were observed by whole cell patch clamp recordings. Results BZC tonically blocked the TTX-r Na+ currents con-centration-dependently, and the percentages of block by 30, 100 and 300 μnol. L-1 BZC on TTX-r Na + currents were ( 18. 83 ± 8.51 )% , ( 33.08 ± 9. 19 )% and ( 58. 91 ± 12. 02 )% respectively. Inaddition, BZC shifted the steady-state inactivation curves of TTX-r Na+ currents to the hyperpolarization direction, also in a concentration-dependent manner. Conclusion BZC may induce analgesic effect by inhibiting TTX-r Na + currents of DRG neurons and shifting steady-state inactivation curves to more negative potential values.

  13. The straintronic spin-neuron. (United States)

    Biswas, Ayan K; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo


    In artificial neural networks, neurons are usually implemented with highly dissipative CMOS-based operational amplifiers. A more energy-efficient implementation is a 'spin-neuron' realized with a magneto-tunneling junction (MTJ) that is switched with a spin-polarized current (representing weighted sum of input currents) that either delivers a spin transfer torque or induces domain wall motion in the soft layer of the MTJ to mimic neuron firing. Here, we propose and analyze a different type of spin-neuron in which the soft layer of the MTJ is switched with mechanical strain generated by a voltage (representing weighted sum of input voltages) and term it straintronic spin-neuron. It dissipates orders of magnitude less energy in threshold operations than the traditional current-driven spin neuron at 0 K temperature and may even be faster. We have also studied the room-temperature firing behaviors of both types of spin neurons and find that thermal noise degrades the performance of both types, but the current-driven type is degraded much more than the straintronic type if both are optimized for maximum energy-efficiency. On the other hand, if both are designed to have the same level of thermal degradation, then the current-driven version will dissipate orders of magnitude more energy than the straintronic version. Thus, the straintronic spin-neuron is superior to current-driven spin neurons.

  14. STDP in recurrent neuronal networks

    Directory of Open Access Journals (Sweden)

    Matthieu Gilson


    Full Text Available Recent results about spike-timing-dependent plasticity (STDP in recurrently connected neurons are reviewed, with a focus on the relationship between the weight dynamics and the emergence of network structure. In particular, the evolution of synaptic weights in the two cases of incoming connections for a single neuron and recurrent connections are compared and contrasted. A theoretical framework is used that is based upon Poisson neurons with a temporally inhomogeneous firing rate and the asymptotic distribution of weights generated by the learning dynamics. Different network configurations examined in recent studies are discussed and an overview of the current understanding of STDP in recurrently connected neuronal networks is presented.

  15. Wnt-3A/beta-catenin signaling induces transcription from the LEF-1 promoter. (United States)

    Filali, Mohammed; Cheng, Ningli; Abbott, Duane; Leontiev, Vladimir; Engelhardt, John F


    Members of the Wnt family of secreted molecules have been established as key factors in determining cell fate and morphogenic signaling. It has long been recognized that Wnt induces morphogenic signaling through the Tcf/LEF-1 cascade by regulating free intracellular levels of beta-catenin, a co-factor for Tcf/LEF-1 transcription factors. In the present study, we have demonstrated that Wnt-3A can also directly induce transcription from the LEF-1 promoter. This induction was dependent on glycogen synthase kinase 3beta inactivation, a rise in free intracellular beta-catenin, and a short 110-bp Wnt-responsive element (WRE) in the LEF-1 promoter. Linear and internal deletion of this WRE led to a dramatic increase in constitutive LEF-1 promoter activity and loss of Wnt-3A responsiveness. In isolation, the 110-bp WRE conferred context-independent Wnt-3A or beta-catenin(S37A) responsiveness to a heterologous SV40 promoter. Studies expressing dominant active and negative forms of LEF-1, beta-catenin, GSK-3beta, and beta-catenin/LEF-1 fusions suggest that Wnt-3A activates the LEF-1 promoter through a beta-catenin-dependent and LEF-1-independent process. Wnt-3A expression also induced multiple changes in the binding of factors to the WRE and suggests that regulatory mechanisms may involve modulation of a multiprotein complex. In summary, these results provide evidence for transcriptional regulation of the LEF-1 promoter by Wnt and enhance the mechanistic understanding of Wnt/beta-catenin signaling in the regulation of LEF-1-dependent developmental processes.

  16. A beta-ray spectrometer based on a two-or three silicon detector coincidence telescope

    Energy Technology Data Exchange (ETDEWEB)

    Horowitz, Y.S. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Physics; Weizman, Y. [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Physics; Hirning, C.R. [Health Physics Dept., Ontario Hydro, Whitby (Canada)


    This report describes the operation of a beta-ray energy spectrometer based on a silicon detector telescope using two or three elements. The front detector is a planar, totally-depleted, silicon surface barrier detector that is 97 {mu}m thick, the back detector is a room-temperature, lithium compensated, silicon detector that is 5000 {mu}m thick, and the intermediate detector is similar to the front detector but 72 {mu}m thick and intended to be used only in intense photon fields. The three detectors are mounted in a light-tight aluminum housing. The capability of the spectrometer to reject photons is based upon the fact that the incident photon will have a small probability of simultaneously losing detectable energy in two detectors, and an even smaller probability of losing detectable energy in all three detectors. Electrons will, however, almost always record measurable events in either the front two or all three detectors. A coincidence requirement between the detectors thus rejects photon induced events. With a 97 {mu}m thick detector the lower energy coincidence threshold is approximately 110 keV. With an ultra-thin 40 {mu}m thick front detector, and operated at 15 C, the spectrometer is capable of detecting even 60-70 keV electrons with a coincidence efficiency of 60%. The spectrometer has been used to measure beta radiation fields in CANDU reactor working environments, and the spectral information is intended to support dose algorithms for the LiF TLD chips used in the Ontario Hydro dosimetry program. (orig.).

  17. Combinatorial Pattern Discovery Approach for the Folding Trajectory Analysis of a beta-Hairpin.

    Directory of Open Access Journals (Sweden)


    Full Text Available The study of protein folding mechanisms continues to be one of the most challenging problems in computational biology. Currently, the protein folding mechanism is often characterized by calculating the free energy landscape versus various reaction coordinates, such as the fraction of native contacts, the radius of gyration, RMSD from the native structure, and so on. In this paper, we present a combinatorial pattern discovery approach toward understanding the global state changes during the folding process. This is a first step toward an unsupervised (and perhaps eventually automated approach toward identification of global states. The approach is based on computing biclusters (or patterned clusters-each cluster is a combination of various reaction coordinates, and its signature pattern facilitates the computation of the Z-score for the cluster. For this discovery process, we present an algorithm of time complexity cinRO((N + nm log n, where N is the size of the output patterns and (n x m is the size of the input with n time frames and m reaction coordinates. To date, this is the best time complexity for this problem. We next apply this to a beta-hairpin folding trajectory and demonstrate that this approach extracts crucial information about protein folding intermediate states and mechanism. We make three observations about the approach: (1 The method recovers states previously obtained by visually analyzing free energy surfaces. (2 It also succeeds in extracting meaningful patterns and structures that had been overlooked in previous works, which provides a better understanding of the folding mechanism of the beta-hairpin. These new patterns also interconnect various states in existing free energy surfaces versus different reaction coordinates. (3 The approach does not require calculating the free energy values, yet it offers an analysis comparable to, and sometimes better than, the methods that use free energy landscapes, thus validating the

  18. Pest protection conferred by a Beta vulgaris serine proteinase inhibitor gene.

    Directory of Open Access Journals (Sweden)

    Ann C Smigocki

    Full Text Available Proteinase inhibitors provide a means of engineering plant resistance to insect pests. A Beta vulgaris serine proteinase inhibitor gene (BvSTI was fused to the constitutive CaMV35S promoter for over-expression in Nicotiana benthamiana plants to study its effect on lepidopteran insect pests. Independently derived BvSTI transgenic tobacco T2 homozygous progeny were shown to have relatively high BvSTI gene transcript levels. BvSTI-specific polyclonal antibodies cross-reacted with the expected 30 kDA recombinant BvSTI protein on Western blots. In gel trypsin inhibitor activity assays revealed a major clear zone that corresponded to the BvSTI proteinase inhibitor that was not detected in the untransformed control plants. BvSTI-transgenic plants were bioassayed for resistance to five lepidopteran insect pests. Spodoptera frugiperda, S. exigua and Manduca sexta larvae fed BvSTI leaves had significant reductions in larval weights as compared to larvae fed on untransformed leaves. In contrast, larval weights increased relative to the controls when Heliothis virescens and Agrotis ipsilon larvae were fed on BvSTI leaves. As the larvae entered the pupal stage, pupal sizes reflected the overall larval weights. Some developmental abnormalities of the pupae and emerging moths were noted. These findings suggest that the sugar beet BvSTI gene may prove useful for effective control of several different lepidopteran insect pests in genetically modified tobacco and other plants. The sugar beet serine proteinase inhibitor may be more effective for insect control because sugar beet is cropped in restricted geographical areas thus limiting the exposure of the insects to sugar beet proteinase inhibitors and build up of non-sensitive midgut proteases.

  19. Pest protection conferred by a Beta vulgaris serine proteinase inhibitor gene. (United States)

    Smigocki, Ann C; Ivic-Haymes, Snezana; Li, Haiyan; Savić, Jelena


    Proteinase inhibitors provide a means of engineering plant resistance to insect pests. A Beta vulgaris serine proteinase inhibitor gene (BvSTI) was fused to the constitutive CaMV35S promoter for over-expression in Nicotiana benthamiana plants to study its effect on lepidopteran insect pests. Independently derived BvSTI transgenic tobacco T2 homozygous progeny were shown to have relatively high BvSTI gene transcript levels. BvSTI-specific polyclonal antibodies cross-reacted with the expected 30 kDA recombinant BvSTI protein on Western blots. In gel trypsin inhibitor activity assays revealed a major clear zone that corresponded to the BvSTI proteinase inhibitor that was not detected in the untransformed control plants. BvSTI-transgenic plants were bioassayed for resistance to five lepidopteran insect pests. Spodoptera frugiperda, S. exigua and Manduca sexta larvae fed BvSTI leaves had significant reductions in larval weights as compared to larvae fed on untransformed leaves. In contrast, larval weights increased relative to the controls when Heliothis virescens and Agrotis ipsilon larvae were fed on BvSTI leaves. As the larvae entered the pupal stage, pupal sizes reflected the overall larval weights. Some developmental abnormalities of the pupae and emerging moths were noted. These findings suggest that the sugar beet BvSTI gene may prove useful for effective control of several different lepidopteran insect pests in genetically modified tobacco and other plants. The sugar beet serine proteinase inhibitor may be more effective for insect control because sugar beet is cropped in restricted geographical areas thus limiting the exposure of the insects to sugar beet proteinase inhibitors and build up of non-sensitive midgut proteases.

  20. The Neuronal Ceroid-Lipofuscinoses (United States)

    Bennett, Michael J.; Rakheja, Dinesh


    The neuronal ceroid-lipofuscinoses (NCL's, Batten disease) represent a group of severe neurodegenerative diseases, which mostly present in childhood. The phenotypes are similar and include visual loss, seizures, loss of motor and cognitive function, and early death. At autopsy, there is massive neuronal loss with characteristic storage in…

  1. Neurones and neuropeptides in coelenterates

    DEFF Research Database (Denmark)

    Grimmelikhuijzen, C J; Ebbesen, Ditte Graff; McFarlane, I D


    The first nervous system probably evolved in coelenterates. Many neurons in coelenterates have morphological characteristics of both sensory and motor neurones, and appear to be multifunctional. Using immunocytochemistry with antisera to the sequence Arg-Phe-NH2 (RFamide), RFamide-like peptides w...... that these neuropeptides play a role in neurotransmission....

  2. Cryopreservation of adherent neuronal networks. (United States)

    Ma, Wu; O'Shaughnessy, Thomas; Chang, Eddie


    Neuronal networks have been widely used for neurophysiology, drug discovery and toxicity testing. An essential prerequisite for future widespread application of neuronal networks is the development of efficient cryopreservation protocols to facilitate their storage and transportation. Here is the first report on cryopreservation of mammalian adherent neuronal networks. Dissociated spinal cord cells were attached to a poly-d-lysine/laminin surface and allowed to form neuronal networks. Adherent neuronal networks were embedded in a thin film of collagen gel and loaded with trehalose prior to transfer to a freezing medium containing DMSO, FBS and culture medium. This was followed by a slow rate of cooling to -80 degrees C for 24 h and then storage for up to 2 months in liquid nitrogen at -196 degrees C. The three components: DMSO, collagen gel entrapment and trehalose loading combined provided the highest post-thaw viability, relative to individual or two component protocols. The post-thaw cells with this protocol demonstrated similar neuronal and astrocytic markers and morphological structure as those detected in unfrozen cells. Fluorescent dye FM1-43 staining revealed active recycling of synaptic vesicles upon depolarizing stimulation in the post-thaw neuronal networks. These results suggest that a combination of DMSO, collagen gel entrapment and trehalose loading can significantly improve conventional slow-cooling methods in cryopreservation of adherent neuronal networks.

  3. AB311. SPR-38 Clarification of the innervation of genitourinary structures: a neuronal tracing study in female mongrel hound dogs (United States)

    Barbe, Mary F.; Gomez-Amaya, Sandra M.; Lamarre, Neil S.; Salvadeo, Danielle M.; Mazzei, Michael; Braverman, Alan S.; Ruggieri, Michael R.


    Objective Many studies focus on either afferent or efferent inputs (but not both), or on one structure of the genitourinary system. Only a few recent studies include information on inputs from sympathetic chain ganglia (SCG), and even fewer have examined the possibility of direct motor (autonomic or somatic) inputs from spinal cord ventral horns to genitourinary end organs. We sought to clarify origins of afferent and efferent information conveyed between the spinal cord, peripheral nervous system ganglia and genitourinary structures using retrograde and anterograde dye tracing methods. Methods Retrograde dyes were injected into the bladder wall, EUS and clitoris of 14 female mongrel dogs (fluorogold, true blue, or nuclear yellow). Dorsal root ganglia (DRG), SCG, caudal mesenteric ganglion (CMG), pelvic plexus ganglia and spinal cord ventral horns were collected and examined for dye-labeled neuronal cell bodies. Detrusor muscle intramural ganglia were examined by injecting an anterograde dye (DiI) into the pelvic nerve’s anterior vesicle branch. Results Retrograde labeled cells were observed in several DRG, representative of afferent input from the bladder, EUS and clitoris. Anterograde labeling revealed a number of intramural ganglia in the bladder wall after distal pelvic nerve labeling. Sympathetic efferents included: (I) labeled cells in the CMG primarily from the bladder, yet small numbers from the EUS and clitoris; (II) labeled cells in SCG primarily from the bladder (widespread) and more localized input from EUS and clitoris; and (III) labeled cells in the intermediolateral cell column of thoracolumbar cord segments directly to the bladder and clitoris, a locale typically considered as sympathetic. Parasympathetic efferents included: (I) labeled neurons in pelvic plexus ganglia in bladder mesenteries; and (II) cells in lamina VII of sacral cord segments directly to the bladder and clitoris, a locale typically considered as sympathetic. Lastly, somatic

  4. Cell biology of neuronal endocytosis. (United States)

    Parton, R G; Dotti, C G


    Endocytosis is the process by which cells take in fluid and components of the plasma membrane. In this way cells obtain nutrients and trophic factors, retrieve membrane proteins for degradation, and sample their environment. In neuronal cells endocytosis is essential for the recycling of membrane after neurotransmitter release and plays a critical role during early developmental stages. Moreover, alterations of the endocytic pathway have been attributed a crucial role in the pathophysiology of certain neurological diseases. Although well characterized at the ultrastructural level, little is known of the dynamics and molecular organization of the neuronal endocytic pathways. In this respect most of our knowledge comes from studies of non-neuronal cells. In this review we will examine the endocytic pathways in neurons from a cell biological viewpoint by making comparisons with non-neuronal cells and in particular with another polarized cell, the epithelial cell.

  5. More questions for mirror neurons. (United States)

    Borg, Emma


    The mirror neuron system is widely held to provide direct access to the motor goals of others. This paper critically investigates this idea, focusing on the so-called 'intentional worry'. I explore two answers to the intentional worry: first that the worry is premised on too limited an understanding of mirror neuron behaviour (Sections 2 and 3), second that the appeal made to mirror neurons can be refined in such a way as to avoid the worry (Section 4). I argue that the first response requires an account of the mechanism by which small-scale gestures are supposedly mapped to larger chains of actions but that none of the extant accounts of this mechanism are plausible. Section 4 then briefly examines refinements of the mirror neuron-mindreading hypothesis which avoid the intentional worry. I conclude that these refinements may well be plausible but that they undermine many of the claims standardly made for mirror neurons.

  6. Phenotypic checkpoints regulate neuronal development. (United States)

    Ben-Ari, Yehezkel; Spitzer, Nicholas C


    Nervous system development proceeds by sequential gene expression mediated by cascades of transcription factors in parallel with sequences of patterned network activity driven by receptors and ion channels. These sequences are cell type- and developmental stage-dependent and modulated by paracrine actions of substances released by neurons and glia. How and to what extent these sequences interact to enable neuronal network development is not understood. Recent evidence demonstrates that CNS development requires intermediate stages of differentiation providing functional feedback that influences gene expression. We suggest that embryonic neuronal functions constitute a series of phenotypic checkpoint signatures; neurons failing to express these functions are delayed or developmentally arrested. Such checkpoints are likely to be a general feature of neuronal development and constitute presymptomatic signatures of neurological disorders when they go awry.

  7. Life and Death of a Neuron (United States)

    ... but neurons are the key players in the brain. Neurons are information messengers. They use electrical impulses and ... inner layers to the outer layers of the brain. Neurons glide along the fibers until they reach their ...

  8. Disinhibition Bursting of Dopaminergic Neurons

    Directory of Open Access Journals (Sweden)

    Collin J Lobb


    Full Text Available Substantia nigra pars compacta (SNpc dopaminergic neurons receive strong tonic inputs from GABAergic neurons in the substantia nigra pars reticulata (SNpr and globus pallidus (GP, and glutamatergic neurons in the subthalamic nucleus. The presence of these tonic inputs raises the possibility that phasic disinhibition may trigger phasic bursts in dopaminergic neurons. We first applied constant NMDA and GABAA conductances onto a two-compartment single cell model of the dopaminergic neuron (Kuznetsov et al., 2006. The model exhibited disinhibition bursting upon stepwise removal of inhibition. A further bifurcation analysis suggests that disinhibition may be more robust than excitation alone in that for most levels of NMDA conductance, the cell remains capable of bursting even after a complete removal of inhibition, whereas too much excitatory input will drive the cell into depolarization block. To investigate the network dynamics of disinhibition, we used a modified version of an integrate-and-fire based model of the basal ganglia (Humphries et al., 2006. Synaptic activity generated in the network was delivered to the two-compartment single cell dopaminergic neuron. Phasic activation of the D1-expressing medium spiny neurons in the striatum (D1STR produced disinhibition bursts in dopaminergic neurons through the direct pathway (D1STR to SNpr to SNpc. Anatomical studies have shown that D1STR neurons have collaterals that terminate in GP. Adding these collaterals to the model, we found that striatal activation increased the intra-burst firing frequency of the disinhibition burst as the weight of this connection was increased. Our studies suggest that striatal activation is a robust means by which disinhibition bursts can be generated by SNpc dopaminergic neurons, and that recruitment of the indirect pathway via collaterals may enhance disinhibition bursting.

  9. Effect of Salvia miltiorrhiza injection on hyperpolarization-activated current channels in dorsal root ganglion neurons of rats%丹参注射液对背根神经节细胞超极化激活电流通道的影响

    Institute of Scientific and Technical Information of China (English)

    陈素; 刘向明


    目的 观察丹参对背根神经节细胞超极化激活通道电流的影响,探讨丹参缓解疼痛和阻滞钙内流,以及减轻钙超载的作用机制.方法 应用全细胞膜片钳技术,观察了丹参注射液对大鼠背根神经节细胞超极化激活电流(Ih)通道的影响.结果 10%,25%和50%的丹参注射液对大鼠背根神经节细胞Ih通道的电流幅值、激活时间常数和翻转电位均没有影响,但可使Ih通道电流的半激活电压向超极化方向偏移.结论 丹参特异性地使Ih通道电流的半激活电压向超极化方向偏移所产生的对外周痛敏的对抗作用,可能也是其缓解疼痛的作用机制之一.%Aim To explore the modulation of Salvia miltiorrhiza on hyperpolarization-activated current (Ih) channels in dorsal root ganglion (DRG) neurons of rats and identify the mechanism of Salvia miltiorrhiza in alleviating pain and inhibiting calcium overload. Methods The effect of Salvia miltiorrhiza injection on Ih channels in DRG neurons of rats were examined by using whole-cell patch clamp technique. Results The experimental results showed that the amplitude of Ih evoked by -150 mV was (-1.06±0.18) nA. The Ih could be fitted well into the single kinetics and the time constant of activation, τ was clearly voltage-dependent with τ=(322.14±28.81) ms at -100 mV, decreasing to τ=(62.51±9.78) ms at -150 mV. The reversal potential of Ih was (-35.03±1.12) mV measured from tail currents. But no significant differences were found between the DRG neurons in the absence and presence of Salvia miltiorrhiza injection (10%, 25%, 50%) in the current amplitude, the time constant of activation and the reversal potential. The only difference between the DRG neurons in the absence and presence of Salvia miltiorrhiza injection was the half-activation potential of Ih. In control recordings the half-activation potential was (-106.07±3.59) mV. By comparison, the half-activation potentials changed to (-111.59±3.79) m

  10. Hematological observations on Arabian SS patients with a homozygosity or heterozygosity for a beta S chromosome with haplotype #31. (United States)

    Kutlar, A; Hattori, Y; Bakioglu, I; Kutlar, F; Kamel, K; Huisman, T H


    Hematological and hemoglobin composition data are presented for seven Arabian SS patients with mild disease and with high Hb F levels varying between 21 and 34%. Four patients were homozygous for a beta S chromosome with a specific haplotype (#31). The data for these four patients were similar to those for three other SS patients (and for five patients reported earlier, Ref. 2) who were heterozygous for the same beta S chromosome (#31) and for a beta S chromosome with another haplotype (mainly #19). These data offer additional evidence indicating that the increased gamma chain production is specific for the beta S chromosome with haplotype #31. The similarities in hematological data and Hb F levels between these two groups of SS patients and the normal Hb F value in Hb S heterozygotes with beta S chromosome (#31) support the suggestion that the increased Hb F production mainly occurs in response to the anemia of the sickle cell disease.

  11. Pathogenesis of motor neuron disease

    Institute of Scientific and Technical Information of China (English)

    Xuefei Wang


    OBJECTIVE: To summarize and analyze the factors and theories related to the attack of motor neuron disease, and comprehensively investigate the pathogenesis of motor neuron disease.DATA SOURCES: A search of Pubmed database was undertaken to identify articles about motor neuron disease published in English from January 1994 to June 2006 by using the keywords of "neurodegenerative diseases". Other literatures were collected by retrieving specific journals and articles.STUDY SELECTION: The data were checked primarily, articles related to the pathogenesis of motor neuron disease were involved, and those obviously irrelated to the articles were excluded.DATA EXTRACTION: Totally 54 articles were collected, 30 of them were involved, and the other 24 were excluded.DATA SYNTHESIS: The pathogenesis of motor neuron disease has multiple factors, and the present related theories included free radical oxidation, excitotoxicity, genetic and immune factors, lack of neurotrophic factor,injury of neurofilament, etc. The studies mainly come from transgenic animal models, cell culture in vitro and patients with familial motor neuron disease, but there are still many restrictions and disadvantages.CONCLUSION: It is necessary to try to find whether there is internal association among different mechanisms,comprehensively investigate the pathogenesis of motor neuron diseases, in order to provide reliable evidence for the clinical treatment.

  12. Salsolinol modulation of dopamine neurons

    Directory of Open Access Journals (Sweden)

    Guiqin eXie


    Full Text Available Salsolinol, a tetrahydroisoquinoline present in the human and rat brains, is the condensation product of dopamine and acetaldehyde, the first metabolite of ethanol. Previous evidence obtained in vivo links salsolinol with the mesolimbic dopaminergic system: salsolinol is self-administered into the posterior of the ventral tegmental area (pVTA of rats; intra-VTA administration of salsolinol induces a strong conditional place preference and increases dopamine release in the nucleus accumbens. However, the underlying neuronal mechanisms are unclear. Here we present an overview of some of the recent research on this topic. Electrophysiological studies reveal that dopaminergic neurons in the posterior ventral tegmental area (pVTA are a target of salsolinol. In acute brain slices from rats, salsolinol increases the excitability and accelerates the ongoing firing of dopamine neurons in the pVTA. Intriguingly, this action of salsolinol involves multiple pre- and post-synaptic mechanisms, including: (a depolarizing the membrane potential of dopamine neurons; (b activating mu opioid receptors on the GABAergic inputs to dopamine neurons, which decreases GABAergic activity and dopamine neurons are disinhibited; and (c enhancing presynaptic glutamatergic transmission onto dopamine neurons via activation of dopamine type 1 receptors, probably situated on the glutamatergic terminals. These novel mechanisms may contribute to the rewarding/reinforcing properties of salsolinol observed in vivo.

  13. A Neuron Model for FPGA Spiking Neuronal Network Implementation

    Directory of Open Access Journals (Sweden)



    Full Text Available We propose a neuron model, able to reproduce the basic elements of the neuronal dynamics, optimized for digital implementation of Spiking Neural Networks. Its architecture is structured in two major blocks, a datapath and a control unit. The datapath consists of a membrane potential circuit, which emulates the neuronal dynamics at the soma level, and a synaptic circuit used to update the synaptic weight according to the spike timing dependent plasticity (STDP mechanism. The proposed model is implemented into a Cyclone II-Altera FPGA device. Our results indicate the neuron model can be used to build up 1K Spiking Neural Networks on reconfigurable logic suport, to explore various network topologies.

  14. Single neuron dynamics and computation. (United States)

    Brunel, Nicolas; Hakim, Vincent; Richardson, Magnus J E


    At the single neuron level, information processing involves the transformation of input spike trains into an appropriate output spike train. Building upon the classical view of a neuron as a threshold device, models have been developed in recent years that take into account the diverse electrophysiological make-up of neurons and accurately describe their input-output relations. Here, we review these recent advances and survey the computational roles that they have uncovered for various electrophysiological properties, for dendritic arbor anatomy as well as for short-term synaptic plasticity.

  15. [Destiny of prepuce between Quran and DRG]. (United States)

    Parigi, G B


    Ritual male circumcision is one of the oldest operations ever performed (Egyptian mommies of the III millennium b.C. have been found circumcised), which has been practiced for thousands of years by Moslems, Jews and various tribes in Africa, America, and Australia; today some 25% of the total world male population is circumcised. Steadily increasing number of Moslem immigrants raised also in our country this issue, up to now completely unknown to Italian culture. In the year 2000 in Italy 21.735 live births from immigrant parents, > 50% of Islamic faith, were recorded: it is therefore easily foreseeable that pediatricians and pediatric surgeons will be increasingly requested to perform this procedure, on the other hand still forbidden by Italian laws and N.H.S. regulations. This paper deals with some anthropological, religious, psychological and legal-economical aspects of ritual male circumcision, in order to offer data for a deeper insight of this complex issue.

  16. MOIRCS Deep Survey. I: DRG Number Counts

    CERN Document Server

    Kajisawa, M; Suzuki, R; Tokoku, C; Uchimoto, Y K; Yoshikawa, T; Akiyama, M; Ichikawa, T; Ouchi, M; Omata, K; Tanaka, I; Nishimura, T; Yamada, T; Kajisawa, Masaru; Konishi, Masahiro; Suzuki, Ryuji; Tokoku, Chihiro; Uchimoto, Yuka Katsuno; Yoshikawa, Tomohiro; Akiyama, Masayuki; Ichikawa, Takashi; Ouchi, Masami; Omata, Koji; Tanaka, Ichi; Nishimura, Tetsuo; Yamada, Toru


    We use very deep near-infrared imaging data taken with Multi-Object InfraRed Camera and Spectrograph (MOIRCS) on the Subaru Telescope to investigate the number counts of Distant Red Galaxies (DRGs). We have observed a 4x7 arcmin^2 field in the Great Observatories Origins Deep Survey North (GOODS-N), and our data reach J=24.6 and K=23.2 (5sigma, Vega magnitude). The surface density of DRGs selected by J-K>2.3 is 2.35+-0.31 arcmin^-2 at K22 is smaller than that expected from the number counts at the brighter magnitude. The result indicates that while there are many bright galaxies at 222 suggest that the mass-dependent color distribution, where most of low-mass galaxies are blue while more massive galaxies tend to have redder colors, had already been established at that epoch.

  17. Nursing case management. Resolving the DRG paradox. (United States)

    Zander, K


    Nursing Case Management as described here was developed in less than ideal conditions: a full census, a 30 per cent increase in patient volume over five years, a nursing shortage, no grants or outside funding, no clinical specialists or clinical ladder, and no computerized documentation system. No more staff or salary was added as we focused our attention on the new tools, roles, and structures necessary to achieve cost and quality outcomes. However, nursing case management has worked because of some very key elements: 1. A firm commitment to the belief that staff nurses must be accountable for the outcomes of the care that they have planned, given, managed, and continuously evaluated. 2. A combination of top-down organizational development strategies with excellent staff nurse involvement at each juncture. 3. Negotiation and collaboration with physicians and hospital administration at key turning points. This includes the relentless articulation of patient-centered care. 4. A willingness to learn and risk together as a whole department--across levels, across specialties. This includes a constant balance of moving from concrete examples and problems to reconceptualizing the issues. 5. Listening, responsiveness, humor, and acknowledging contributions of everyone. More than any other principal, the case manager must be a central caregiver to a patient to ensure cost/quality outcomes. Otherwise case management only adds to the cost of health care by adding another level of bureaucracy. Nurses have always managed the care of patients, but to stay effective and committed, they need to take increased authority in their patients' entire episode of care and develop formal collaborative practice groups. In other words: "Prospective payment has changed the health care product from a day of care (or a visit) to an entire case or episode of illness. More than just a new way of paying for care, it has changed our way of planning, managing, and thinking about health care." Looking at the future entails understanding our business, and then changing our practice patterns for the change in the times. Necessity will foster invention; Nursing Case Management provides a model and technology for innovation.

  18. The neuronal and actin commitment: Why do neurons need rings? (United States)

    Leite, Sérgio Carvalho; Sousa, Mónica Mendes


    The role of the actin cytoskeleton in neurons has been extensively studied in actin-enriched compartments such as the growth cone and dendritic spines. The recent discovery of actin rings in the axon shaft and in dendrites, together with the identification of axon actin trails, has advanced our understanding on actin organization and dynamics in neurons. However, specifically in the case of actin rings, the mechanisms regulating their nucleation and assembly, and the functions that they may exert in axons and dendrites remain largely unexplored. Here we discuss the possible structural, mechanistic and functional properties of the subcortical neuronal cytoskeleton putting the current knowledge in perspective with the information available on actin rings formed in other biological contexts, and with the organization of actin-spectrin lattices in other cell types. The detailed analysis of these novel neuronal actin ring structures, together with the elucidation of the function of actin-binding proteins in neuron biology, has a large potential to uncover new mechanisms of neuronal function under normal conditions that may have impact in our understanding of axon degeneration and regeneration. © 2016 Wiley Periodicals, Inc.

  19. Tinbergen on mirror neurons. (United States)

    Heyes, Cecilia


    Fifty years ago, Niko Tinbergen defined the scope of behavioural biology with his four problems: causation, ontogeny, survival value and evolution. About 20 years ago, there was another highly significant development in behavioural biology-the discovery of mirror neurons (MNs). Here, I use Tinbergen's original four problems (rather than the list that appears in textbooks) to highlight the differences between two prominent accounts of MNs, the genetic and associative accounts; to suggest that the latter provides the defeasible 'best explanation' for current data on the causation and ontogeny of MNs; and to argue that functional analysis, of the kind that Tinbergen identified somewhat misleadingly with studies of 'survival value', should be a high priority for future research. In this kind of functional analysis, system-level theories would assign MNs a small, but potentially important, role in the achievement of action understanding-or another social cognitive function-by a production line of interacting component processes. These theories would be tested by experimental intervention in human and non-human animal samples with carefully documented and controlled developmental histories.

  20. Neuronal intestinal dysplasia. (United States)

    Rintala, R; Rapola, J; Louhimo, I


    A series of 21 patients with NID is presented. A histologic and histochemical picture of NID was seen in an heterogenous group of patients. NID was associated with bowel obstruction and/or perforation in six neonates and infants. One neonate died. During follow-up the bowel histology gradually normalized in four of the five patients. NID was found incidentally in four patients with anorectal malformations and two with Hirschsprung's disease. Three patients with Hirschsprung's disease and associated NID had chronic proctitis; one patient with an anorectal anomaly had chronic obstipation and megacolon and one proctitis. Two children with multiple endocrine neoplasia 2b syndrome and chronic obstipation had typical NID in their rectum biopsies, as did a 50-year-old woman with CIIP. The clinical heterogeneity of patients with NID suggests that NID may not be a distinct clinical entity but rather a reaction of the neuronal network of the bowel wall and could be caused either by congenital or secondary factors.

  1. Neuronal boost to evolutionary dynamics. (United States)

    de Vladar, Harold P; Szathmáry, Eörs


    Standard evolutionary dynamics is limited by the constraints of the genetic system. A central message of evolutionary neurodynamics is that evolutionary dynamics in the brain can happen in a neuronal niche in real time, despite the fact that neurons do not reproduce. We show that Hebbian learning and structural synaptic plasticity broaden the capacity for informational replication and guided variability provided a neuronally plausible mechanism of replication is in place. The synergy between learning and selection is more efficient than the equivalent search by mutation selection. We also consider asymmetric landscapes and show that the learning weights become correlated with the fitness gradient. That is, the neuronal complexes learn the local properties of the fitness landscape, resulting in the generation of variability directed towards the direction of fitness increase, as if mutations in a genetic pool were drawn such that they would increase reproductive success. Evolution might thus be more efficient within evolved brains than among organisms out in the wild.

  2. Modeling neuronal vulnerability in ALS. (United States)

    Roselli, Francesco; Caroni, Pico


    Using computational models of motor neuron ion fluxes, firing properties, and energy requirements, Le Masson et al. (2014) reveal how local imbalances in energy homeostasis may self-amplify and contribute to neurodegeneration in ALS.

  3. Neuronal boost to evolutionary dynamics (United States)

    de Vladar, Harold P.; Szathmáry, Eörs


    Standard evolutionary dynamics is limited by the constraints of the genetic system. A central message of evolutionary neurodynamics is that evolutionary dynamics in the brain can happen in a neuronal niche in real time, despite the fact that neurons do not reproduce. We show that Hebbian learning and structural synaptic plasticity broaden the capacity for informational replication and guided variability provided a neuronally plausible mechanism of replication is in place. The synergy between learning and selection is more efficient than the equivalent search by mutation selection. We also consider asymmetric landscapes and show that the learning weights become correlated with the fitness gradient. That is, the neuronal complexes learn the local properties of the fitness landscape, resulting in the generation of variability directed towards the direction of fitness increase, as if mutations in a genetic pool were drawn such that they would increase reproductive success. Evolution might thus be more efficient within evolved brains than among organisms out in the wild. PMID:26640653

  4. [Some characteristics of vertigo in vestibular neuronitis]. (United States)

    Skliut, I A; Likhachev, S A; Rybina, O V


    The authors present a detailed clinical analysis of objective neurological symptoms and vertigo in patients with vestibular neuronitis. Diagnostic criteria are specified allowing differentiation between vertigo and dizziness, pathognomonic signs of vestibular neuronitis are outlined. Peripheral location of the pathological process in vestibular neuronitis is suggested. How rotating vertigo is forming in patients with vestibular neuronitis is hypothesized.

  5. Calcium Homeostasis in ageing neurons

    Directory of Open Access Journals (Sweden)

    Vassiliki eNikoletopoulou


    Full Text Available The nervous system becomes increasingly vulnerable to insults and prone to dysfunction during ageing. Age-related decline of neuronal function is manifested by the late onset of many neurodegenerative disorders, as well as by reduced signalling and processing capacity of individual neuron populations. Recent findings indicate that impairment of Ca2+ homeostasis underlies the increased susceptibility of neurons to damage, associated with the ageing process. However, the impact of ageing on Ca2+ homeostasis in neurons remains largely unknown. Here, we survey the molecular mechanisms that mediate neuronal Ca2+ homeostasis and discuss the impact of ageing on their efficacy. To address the question of how ageing impinges on Ca2+ homeostasis, we consider potential nodes through which mechanisms regulating Ca2+ levels interface with molecular pathways known to influence the process of ageing and senescent decline. Delineation of this crosstalk would facilitate the development of interventions aiming to fortify neurons against age-associated functional deterioration and death by augmenting Ca2+ homeostasis.

  6. More sensitivity of cortical GABAergic neurons than glutamatergic neurons in response to acidosis. (United States)

    Liu, Hua; Li, Fang; Wang, Chunyan; Su, Zhiqiang


    Acidosis impairs brain functions. Neuron-specific mechanisms underlying acidosis-induced brain dysfunction remain elusive. We studied the sensitivity of cortical GABAergic neurons and glutamatergic neurons to acidosis by whole-cell recording in brain slices. The acidification to the neurons was induced by perfusing artificial cerebral spinal fluid with lower pH. This acidification impairs excitability and synaptic transmission in the glutamatergic and GABAergic neurons. Acidosis impairs spiking capacity in the GABAergic neurons more than in the glutamatergic neurons. Acidosis also strengthens glutamatergic synaptic transmission and attenuates GABAergic synaptic transmission on the GABAergic neurons more than the glutamatergic neurons, which results in the functional impairment of these GABAergic neurons. This acidosis-induced dysfunction predominantly in the cortical GABAergic neurons drives the homeostasis of neuronal networks toward overexcitation and exacerbates neuronal impairment.

  7. Automated identification of neurons and their locations

    CERN Document Server

    Inglis, Andrew; Roe, Dan L; Stanley, H E; Rosene, Douglas L; Urbanc, Brigita


    Individual locations of many neuronal cell bodies (>10^4) are needed to enable statistically significant measurements of spatial organization within the brain such as nearest-neighbor and microcolumnarity measurements. In this paper, we introduce an Automated Neuron Recognition Algorithm (ANRA) which obtains the (x,y) location of individual neurons within digitized images of Nissl-stained, 30 micron thick, frozen sections of the cerebral cortex of the Rhesus monkey. Identification of neurons within such Nissl-stained sections is inherently difficult due to the variability in neuron staining, the overlap of neurons, the presence of partial or damaged neurons at tissue surfaces, and the presence of non-neuron objects, such as glial cells, blood vessels, and random artifacts. To overcome these challenges and identify neurons, ANRA applies a combination of image segmentation and machine learning. The steps involve active contour segmentation to find outlines of potential neuron cell bodies followed by artificial ...

  8. Hyperexcitability in Spinal WDR Neurons following Experimental Disc Herniation Is Associated with Upregulation of Fractalkine and Its Receptor in Nucleus Pulposus and the Dorsal Root Ganglion (United States)

    Moen, Aurora; Haugen, Fred; Gjerstad, Johannes


    Introduction. Lumbar radicular pain following intervertebral disc herniation may be associated with a local inflammatory response induced by nucleus pulposus (NP) cells. Methods. In anaesthetized Lewis rats, extracellular single unit recordings of wide dynamic range (WDR) neurons in the dorsal horn and qPCR were used to explore the effect of NP application onto the dorsal nerve roots (L3–L5). Results. A clear increase in C-fiber response was observed following NP conditioning. In the NP tissue, the expression of interleukin-1β (IL-1β), colony stimulating factor 1 (Csf1), fractalkine (CX3CL1), and the fractalkine receptor CX3CR1 was increased. Minocycline, an inhibitor of microglial activation, inhibited the increase in neuronal activity and attenuated the increase in IL-1β, Csf1, CX3L1, and CX3CR1 expression in NP tissue. In addition, the results demonstrated an increase in the expression of TNF, CX3CL1, and CX3CR1 in the dorsal root ganglions (DRGs). Conclusion. Hyperexcitability in the pain pathways and the local inflammation after disc herniation may involve upregulation of CX3CL1 signaling in both the NP and the DRG. PMID:28116212

  9. Hyperexcitability in Spinal WDR Neurons following Experimental Disc Herniation Is Associated with Upregulation of Fractalkine and Its Receptor in Nucleus Pulposus and the Dorsal Root Ganglion

    Directory of Open Access Journals (Sweden)

    Daniel Pitz Jacobsen


    Full Text Available Introduction. Lumbar radicular pain following intervertebral disc herniation may be associated with a local inflammatory response induced by nucleus pulposus (NP cells. Methods. In anaesthetized Lewis rats, extracellular single unit recordings of wide dynamic range (WDR neurons in the dorsal horn and qPCR were used to explore the effect of NP application onto the dorsal nerve roots (L3–L5. Results. A clear increase in C-fiber response was observed following NP conditioning. In the NP tissue, the expression of interleukin-1β (IL-1β, colony stimulating factor 1 (Csf1, fractalkine (CX3CL1, and the fractalkine receptor CX3CR1 was increased. Minocycline, an inhibitor of microglial activation, inhibited the increase in neuronal activity and attenuated the increase in IL-1β, Csf1, CX3L1, and CX3CR1 expression in NP tissue. In addition, the results demonstrated an increase in the expression of TNF, CX3CL1, and CX3CR1 in the dorsal root ganglions (DRGs. Conclusion. Hyperexcitability in the pain pathways and the local inflammation after disc herniation may involve upregulation of CX3CL1 signaling in both the NP and the DRG.

  10. Isoflurane-induced neuronal apoptosis in developing hippocampal neurons

    Institute of Scientific and Technical Information of China (English)

    Hongliang Liu; Tijun Dai; Weitao Guo


    We hypothesized that the P2X7 receptor may be the target of isoflurane, so we investigated the roles of the P2X7 receptor and inositol triphosphate receptor in calcium overload and neuronal apoptosis induced by isoflurane in cultured embryonic rat hippocampal neurons. Results showed that isoflurane induced widespread neuronal apoptosis and significantly increased cytoplasmic Ca2+. Blockade of P2X7 receptors or removal of extracellular Ca2+ combined with blockade of inositol triphosphate receptors completely inhibited apoptosis or increase in cytoplasmic Ca2+. Removal of extracellular Ca2+ or blockade of inositol triphosphate receptor alone could partly inhibit these effects of isoflurane. Isoflurane could directly activate P2X7-gated channels and induce inward currents, but did not affect the expression of P2X7 receptor protein in neurons. These findings indicate that the mechanism by which isoflurane induced neuronal apoptosis in rat developing brain was mediated by intracellular calcium overload, which was caused by P2X7 receptor mediated calcium influx and inositol triphosphate receptor mediated calcium release.

  11. Neuronize: a tool for building realistic neuronal cell morphologies (United States)

    Brito, Juan P.; Mata, Susana; Bayona, Sofia; Pastor, Luis; DeFelipe, Javier; Benavides-Piccione, Ruth


    This study presents a tool, Neuronize, for building realistic three-dimensional models of neuronal cells from the morphological information extracted through computer-aided tracing applications. Neuronize consists of a set of methods designed to build 3D neural meshes that approximate the cell membrane at different resolution levels, allowing a balance to be reached between the complexity and the quality of the final model. The main contribution of the present study is the proposal of a novel approach to build a realistic and accurate 3D shape of the soma from the incomplete information stored in the digitally traced neuron, which usually consists of a 2D cell body contour. This technique is based on the deformation of an initial shape driven by the position and thickness of the first order dendrites. The addition of a set of spines along the dendrites completes the model, building a final 3D neuronal cell suitable for its visualization in a wide range of 3D environments. PMID:23761740

  12. Inhibitory Activity of Yokukansankachimpihange against Nerve Growth Factor-Induced Neurite Growth in Cultured Rat Dorsal Root Ganglion Neurons

    Directory of Open Access Journals (Sweden)

    Chiaki Murayama


    Full Text Available Chronic pruritus is a major and distressing symptom of many cutaneous diseases, however, the treatment remains a challenge in the clinic. The traditional Chinese-Japanese medicine (Kampo medicine is a conservative and increasingly popular approach to treat chronic pruritus for both patients and medical providers. Yokukansankachimpihange (YKH, a Kampo formula has been demonstrated to be effective in the treatment of itching of atopic dermatitis in Japan although its pharmacological mechanism is unknown clearly. In an attempt to clarify its pharmacological actions, in this study, we focused on the inhibitory activity of YKH against neurite growth induced with nerve growth factor (NGF in cultured rat dorsal root ganglion (DRG neurons because epidermal hyperinnervation is deeply related to itch sensitization. YKH showed approximately 200-fold inhibitory activity against NGF-induced neurite growth than that of neurotropin (positive control, a drug used clinically for treatment of chronic pruritus. Moreover, it also found that Uncaria hook, Bupleurum root and their chemical constituents rhynchophylline, hirsutine, and saikosaponin a, d showed inhibitory activities against NGF-induced neurite growth, suggesting they should mainly contribute to the inhibitory activity of YKH. Further study on the effects of YKH against epidermal nerve density in “itch-scratch” animal models is under investigation.

  13. Stochastic phase-change neurons (United States)

    Tuma, Tomas; Pantazi, Angeliki; Le Gallo, Manuel; Sebastian, Abu; Eleftheriou, Evangelos


    Artificial neuromorphic systems based on populations of spiking neurons are an indispensable tool in understanding the human brain and in constructing neuromimetic computational systems. To reach areal and power efficiencies comparable to those seen in biological systems, electroionics-based and phase-change-based memristive devices have been explored as nanoscale counterparts of synapses. However, progress on scalable realizations of neurons has so far been limited. Here, we show that chalcogenide-based phase-change materials can be used to create an artificial neuron in which the membrane potential is represented by the phase configuration of the nanoscale phase-change device. By exploiting the physics of reversible amorphous-to-crystal phase transitions, we show that the temporal integration of postsynaptic potentials can be achieved on a nanosecond timescale. Moreover, we show that this is inherently stochastic because of the melt-quench-induced reconfiguration of the atomic structure occurring when the neuron is reset. We demonstrate the use of these phase-change neurons, and their populations, in the detection of temporal correlations in parallel data streams and in sub-Nyquist representation of high-bandwidth signals.

  14. Brain Neurons as Quantum Computers: (United States)

    Bershadskii, A.; Dremencov, E.; Bershadskii, J.; Yadid, G.

    The question: whether quantum coherent states can sustain decoherence, heating and dissipation over time scales comparable to the dynamical timescales of brain neurons, has been actively discussed in the last years. A positive answer on this question is crucial, in particular, for consideration of brain neurons as quantum computers. This discussion was mainly based on theoretical arguments. In the present paper nonlinear statistical properties of the Ventral Tegmental Area (VTA) of genetically depressive limbic brain are studied in vivo on the Flinders Sensitive Line of rats (FSL). VTA plays a key role in the generation of pleasure and in the development of psychological drug addiction. We found that the FSL VTA (dopaminergic) neuron signals exhibit multifractal properties for interspike frequencies on the scales where healthy VTA dopaminergic neurons exhibit bursting activity. For high moments the observed multifractal (generalized dimensions) spectrum coincides with the generalized dimensions spectrum calculated for a spectral measure of a quantum system (so-called kicked Harper model, actively used as a model of quantum chaos). This observation can be considered as a first experimental (in vivo) indication in the favor of the quantum (at least partially) nature of brain neurons activity.

  15. The neuronal code for number. (United States)

    Nieder, Andreas


    Humans and non-human primates share an elemental quantification system that resides in a dedicated neural network in the parietal and frontal lobes. In this cortical network, 'number neurons' encode the number of elements in a set, its cardinality or numerosity, irrespective of stimulus appearance across sensory motor systems, and from both spatial and temporal presentation arrays. After numbers have been extracted from sensory input, they need to be processed to support goal-directed behaviour. Studying number neurons provides insights into how information is maintained in working memory and transformed in tasks that require rule-based decisions. Beyond an understanding of how cardinal numbers are encoded, number processing provides a window into the neuronal mechanisms of high-level brain functions.

  16. Correlations and Neuronal Population Information. (United States)

    Kohn, Adam; Coen-Cagli, Ruben; Kanitscheider, Ingmar; Pouget, Alexandre


    Brain function involves the activity of neuronal populations. Much recent effort has been devoted to measuring the activity of neuronal populations in different parts of the brain under various experimental conditions. Population activity patterns contain rich structure, yet many studies have focused on measuring pairwise relationships between members of a larger population-termed noise correlations. Here we review recent progress in understanding how these correlations affect population information, how information should be quantified, and what mechanisms may give rise to correlations. As population coding theory has improved, it has made clear that some forms of correlation are more important for information than others. We argue that this is a critical lesson for those interested in neuronal population responses more generally: Descriptions of population responses should be motivated by and linked to well-specified function. Within this context, we offer suggestions of where current theoretical frameworks fall short.

  17. Turning skin into dopamine neurons

    Institute of Scientific and Technical Information of China (English)

    Malin Parmar; Johan Jakobsson


    The possibility to generate neurons from fibroblasts became a reality with the development of iPS technology a few years ago.By reprogramming somatic cells using transcription factor (TF) overexpression,it is possible to generate pluripotent stem cells that then can be differentiated into any somatic cell type including various subtypes of neurons.This raises the possibility of using donor-matched or even patientspecific cells for cell therapy of neurological disorders such as Parkinson's disease (PD),Huntington's disease and stroke.Supporting this idea,dopamine neurons,which are the cells dying in PD,derived from human iPS cells have been demonstrated to survive transplantation and reverse motor symptoms in animal models of PD [1].

  18. 清络通痹方对小鼠疼痛行为及 DRG 中 COX-2表达和血 PGE2的影响%Effects of Qingluo Tongbi Compound on Pain Behavior and Expression of COX-2 in Dorsal Root Ganglion and Blood PGE2

    Institute of Scientific and Technical Information of China (English)

    朱亚梅; 周玲玲; 彭孝武; 唐宗湘; 周学平


    目的:观察清络通痹方对疼痛模型和胶原关节炎(CIA)小鼠模型的疼痛行为的影响,及背根神经节(DRG)环氧合酶(COX)-2 mRNA 及血前列腺素 E2(PGE2)含量的影响,初步探讨清络通痹方干预类风湿关节炎疼痛的作用及可能机制。方法采用热板和醋酸扭体致痛模型,分为空白对照组、塞来昔布组(30 mg/kg)、清络通痹低剂量组(4.35 g/kg)、中剂量组(8.70 g/kg)、高剂量组(17.4 g/kg),观察各组痛阈值和扭体次数的改变。DBA/1小鼠,复制 CIA 模型,随机分为空白对照组、模型组、清络通痹方组(8.7 g/kg)及塞来昔布组(30 mg/kg),观察一般情况及关节肿胀,各组机械缩足反射阈值(MWT)和热缩足反射阈值(TWL)的变化,灌胃给药4周后,检测 DRG COX-2 mRNA 及血清 PGE2含量。结果清络通痹方使小鼠热板法致痛模型痛阈值提高、醋酸扭体法致痛模型扭体次数减少(P <0.01);可显著减轻 CIA 小鼠足肿胀(P <0.05),提高其 MWT(P<0.01)和 PWL(P <0.05)阈值,降低 DRG 中 COX-2 mRNA 的表达(P <0.05)和血 PGE2的含量(P <0.05)。结论清络通痹方具有一定的镇痛作用,其镇痛机制可能与抑制 DRG 中 COX-2 mRNA 表达和血清中 PGE2含量相关。%ABSTRACT:OBJECTIVE To study the effects of Qingluo Tongbi Compound(QLT)on pain behavior and COX-2 mRNA ex-pression in dorsal root ganglion(DRG)and blood PGE2 concentration,and to explore the mechanisms of pain in rheumatoid ar-thritis.METHODS The mice were randomly divided into control group,celecoxib 30 mg∕kg,QLT 4.35 g∕kg,QLT 8.70 g∕kg and QLT 1 7.4 g∕kg groups.The mice pain threshold change were measured by hot plate method,and body torsion times were tested by acetic acid twisting method.The collagen-induced arthritis(CIA) was induced by collagenⅡ in DBA∕1 mice. The mice were randomly divided into control group,CIA group,celecoxib 30 mg∕kg group,QLT 8.70 g∕kg.The paws swell-ing,mechanical withdrawal

  19. Prospective Coding by Spiking Neurons.

    Directory of Open Access Journals (Sweden)

    Johanni Brea


    Full Text Available Animals learn to make predictions, such as associating the sound of a bell with upcoming feeding or predicting a movement that a motor command is eliciting. How predictions are realized on the neuronal level and what plasticity rule underlies their learning is not well understood. Here we propose a biologically plausible synaptic plasticity rule to learn predictions on a single neuron level on a timescale of seconds. The learning rule allows a spiking two-compartment neuron to match its current firing rate to its own expected future discounted firing rate. For instance, if an originally neutral event is repeatedly followed by an event that elevates the firing rate of a neuron, the originally neutral event will eventually also elevate the neuron's firing rate. The plasticity rule is a form of spike timing dependent plasticity in which a presynaptic spike followed by a postsynaptic spike leads to potentiation. Even if the plasticity window has a width of 20 milliseconds, associations on the time scale of seconds can be learned. We illustrate prospective coding with three examples: learning to predict a time varying input, learning to predict the next stimulus in a delayed paired-associate task and learning with a recurrent network to reproduce a temporally compressed version of a sequence. We discuss the potential role of the learning mechanism in classical trace conditioning. In the special case that the signal to be predicted encodes reward, the neuron learns to predict the discounted future reward and learning is closely related to the temporal difference learning algorithm TD(λ.

  20. Prolactin potentiates the activity of acid-sensing ion channels in female rat primary sensory neurons. (United States)

    Liu, Ting-Ting; Qu, Zu-Wei; Ren, Cuixia; Gan, Xiong; Qiu, Chun-Yu; Hu, Wang-Ping


    Prolactin (PRL) is a polypeptide hormone produced and released from the pituitary and extrapituitary tissues. It regulates activity of nociceptors and causes hyperalgesia in pain conditions, but little is known the molecular mechanism. We report here that PRL can exert a potentiating effect on the functional activity of acid-sensing ion channels (ASICs), key sensors for extracellular protons. First, PRL dose-dependently increased the amplitude of ASIC currents with an EC50 of (5.89 ± 0.28) × 10(-8) M. PRL potentiation of ASIC currents was also pH dependent. Second, PRL potentiation of ASIC currents was blocked by Δ1-9-G129R-hPRL, a PRL receptor antagonist, and removed by intracellular dialysis of either protein kinase C inhibitor GF109203X, protein interacting with C-kinase 1(PICK1) inhibitor FSC-231, or PI3K inhibitor AS605240. Third, PRL altered acidosis-evoked membrane excitability of DRG neurons and caused a significant increase in the amplitude of the depolarization and the number of spikes induced by acid stimuli. Four, PRL exacerbated nociceptive responses to injection of acetic acid in female rats. Finally, PRL displayed a stronger effect on ASIC mediated-currents and nociceptive behavior in intact female rats than OVX female and male rats and thus modulation of PRL may be gender-dependent. These results suggest that PRL up-regulates the activity of ASICs and enhances ASIC mediated nociceptive responses in female rats, which reveal a novel peripheral mechanism underlying PRL involvement in hyperalgesia.

  1. Neuronal involvement in cisplatin neuropathy

    DEFF Research Database (Denmark)

    Krarup-Hansen, A; Helweg-Larsen, Susanne Elisabeth; Schmalbruch, H


    Although it is well known that cisplatin causes a sensory neuropathy, the primary site of involvement is not established. The clinical symptoms localized in a stocking-glove distribution may be explained by a length dependent neuronopathy or by a distal axonopathy. To study whether the whole neuron...... of large dorsal root ganglion cells. Motor conduction studies, autonomic function and warm and cold temperature sensation remained unchanged at all doses of cisplatin treatment. The results of these studies are consistent with degeneration of large sensory neurons whereas there was no evidence of distal...

  2. Calcium signals in olfactory neurons. (United States)

    Tareilus, E; Noé, J; Breer, H


    Laser scanning confocal microscopy in combination with the fluorescent calcium indicators Fluo-3 and Fura-Red was employed to estimate the intracellular concentration of free calcium ions in individual olfactory receptor neurons and to monitor temporal and spatial changes in the Ca(2+)-level upon stimulation. The chemosensory cells responded to odorants with a significant increase in the calcium concentration, preferentially in the dendritic knob. Applying various stimulation paradigma, it was found that in a population of isolated cells, subsets of receptor neurons display distinct patterns of responsiveness.

  3. Neuronal involvement in cisplatin neuropathy

    DEFF Research Database (Denmark)

    Krarup-Hansen, A; Helweg-Larsen, Susanne Elisabeth; Schmalbruch, H;


    of large dorsal root ganglion cells. Motor conduction studies, autonomic function and warm and cold temperature sensation remained unchanged at all doses of cisplatin treatment. The results of these studies are consistent with degeneration of large sensory neurons whereas there was no evidence of distal......Although it is well known that cisplatin causes a sensory neuropathy, the primary site of involvement is not established. The clinical symptoms localized in a stocking-glove distribution may be explained by a length dependent neuronopathy or by a distal axonopathy. To study whether the whole neuron...

  4. Electrodiagnosis of motor neuron disease. (United States)

    Duleep, Anuradha; Shefner, Jeremy


    Electrodiagnostic testing has proved useful in helping to establish the diagnosis of amyotrophic lateral sclerosis by eliminating possible disease mimics and by demonstrating abnormalities in body areas that are clinically unaffected. Electrodiagnosis begins with an understanding of the clinical features of the disease, because clinical correlation is essential. To improve the sensitivity of the electrophysiologic evaluation, the Awaji criteria have been proposed as a modification to the revised El Escorial criteria. Although techniques to evaluate corticomotor neuron abnormalities and to quantify lower motor neuron loss have been developed, they remain primarily research techniques and have not yet influenced clinical practice.

  5. G(o) transduces GABAB-receptor modulation of N-type calcium channels in cultured dorsal root ganglion neurons. (United States)

    Menon-Johansson, A S; Berrow, N; Dolphin, A C


    High-voltage-activated (HVA) calcium channel currents (IBa) were recorded from acutely replated cultured dorsal root ganglion (DRG) neurons. IBa was irreversibly inhibited by 56.9 +/- 2.7% by 1 microM omega-conotoxin-GVIA (omega-CTx-GVIA), whereas the 1,4-dihydropyridine antagonist nicardipine was ineffective. The selective gamma-aminobutyric acidB (GABAB) agonist, (-)-baclofen (50 microM), inhibited the HVA IBa by 30.7 +/- 5.4%. Prior application of omega-CTx-GVIA completely occluded inhibition of the HVA IBa by (-)-baclofen, indicating that in this preparation (-)-baclofen inhibits N-type current. To investigate which G protein subtype was involved, cells were replated in the presence of anti-G protein antisera. Under these conditions the antibodies were shown to enter the cells through transient pores created during the replating procedure. Replating DRGs in the presence of anti-G(o) antiserum, raised against the C-terminal decapeptide of the G alpha o subunit, reduced (-)-baclofen inhibition of the HVA IBa, whereas replating DRGs in the presence of the anti-Gi antiserum did not. Using anti-G alpha o antisera (1:2000) and confocal laser microscopy, G alpha o localisation was investigated in both unreplated and replated neurons. G alpha o immunoreactivity was observed at the plasma membrane, neurites, attachment plaques and perinuclear region, and was particularly pronounced at points of cell-to-cell contact. The plasma membrane G alpha o immunoreactivity was completely blocked by preincubation with the immunising G alpha o undecapeptide (1 for 1 h at 37 degrees C. A similar treatment also blocked recognition of G alpha o in brain membranes on immunoblots.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Human motor neuron progenitor transplantation leads to endogenous neuronal sparing in 3 models of motor neuron loss. (United States)

    Wyatt, Tanya J; Rossi, Sharyn L; Siegenthaler, Monica M; Frame, Jennifer; Robles, Rockelle; Nistor, Gabriel; Keirstead, Hans S


    Motor neuron loss is characteristic of many neurodegenerative disorders and results in rapid loss of muscle control, paralysis, and eventual death in severe cases. In order to investigate the neurotrophic effects of a motor neuron lineage graft, we transplanted human embryonic stem cell-derived motor neuron progenitors (hMNPs) and examined their histopathological effect in three animal models of motor neuron loss. Specifically, we transplanted hMNPs into rodent models of SMA (Δ7SMN), ALS (SOD1 G93A), and spinal cord injury (SCI). The transplanted cells survived and differentiated in all models. In addition, we have also found that hMNPs secrete physiologically active growth factors in vivo, including NGF and NT-3, which significantly enhanced the number of spared endogenous neurons in all three animal models. The ability to maintain dying motor neurons by delivering motor neuron-specific neurotrophic support represents a powerful treatment strategy for diseases characterized by motor neuron loss.

  7. [What mirror neurons have revealed: revisited]. (United States)

    Murata, Akira; Maeda, Kazutaka


    The first paper on mirror neurons was published in 1992. In the span of over two decades since then, much knowledge about the relationship between social cognitive function and the motor control system has been accumulated. Direct matching of visual actions and their corresponding motor representations is the most important functional property of mirror neuron. Many studies have emphasized intrinsic simulation as a core concept for mirror neurons. Mirror neurons are thought to play a role in social cognitive function. However, the function of mirror neurons in the macaque remains unclear, because such cognitive functions are limited or lacking in macaque monkeys. It is therefore important to discuss these neurons in the context of motor function. Rizzolatti and colleagues have stressed that the most important function of mirror neurons in macaques is recognition of actions performed by other individuals. I suggest that mirror neurons in the Macaque inferior pariental lobule might be correlated with body schema. In the parieto-premotor network, matching of corollary discharge and actual sensory feedback is an essential neuronal operation. Recently, neurons showing mirror properties were found in some cortical areas outside the mirror neuron system. The current work would revisit the outcomes of mirror neuron studies to discuss the function of mirror neurons in the monkey.

  8. Computing with Spiking Neuron Networks

    NARCIS (Netherlands)

    Paugam-Moisy, H.; Bohte, S.M.; Rozenberg, G.; Baeck, T.H.W.; Kok, J.N.


    Abstract Spiking Neuron Networks (SNNs) are often referred to as the 3rd gener- ation of neural networks. Highly inspired from natural computing in the brain and recent advances in neurosciences, they derive their strength and interest from an ac- curate modeling of synaptic interactions between neu

  9. Neuronal circuits of fear extinction. (United States)

    Herry, Cyril; Ferraguti, Francesco; Singewald, Nicolas; Letzkus, Johannes J; Ehrlich, Ingrid; Lüthi, Andreas


    Fear extinction is a form of inhibitory learning that allows for the adaptive control of conditioned fear responses. Although fear extinction is an active learning process that eventually leads to the formation of a consolidated extinction memory, it is a fragile behavioural state. Fear responses can recover spontaneously or subsequent to environmental influences, such as context changes or stress. Understanding the neuronal substrates of fear extinction is of tremendous clinical relevance, as extinction is the cornerstone of psychological therapy of several anxiety disorders and because the relapse of maladaptative fear and anxiety is a major clinical problem. Recent research has begun to shed light on the molecular and cellular processes underlying fear extinction. In particular, the acquisition, consolidation and expression of extinction memories are thought to be mediated by highly specific neuronal circuits embedded in a large-scale brain network including the amygdala, prefrontal cortex, hippocampus and brain stem. Moreover, recent findings indicate that the neuronal circuitry of extinction is developmentally regulated. Here, we review emerging concepts of the neuronal circuitry of fear extinction, and highlight novel findings suggesting that the fragile phenomenon of extinction can be converted into a permanent erasure of fear memories. Finally, we discuss how research on genetic animal models of impaired extinction can further our understanding of the molecular and genetic bases of human anxiety disorders.

  10. What do mirror neurons mirror?

    NARCIS (Netherlands)

    Uithol, S.; Rooij, I.J.E.I. van; Bekkering, H.; Haselager, W.F.G.


    Single cell recordings in monkeys provide strong evidence for an important role of the motor system in action understanding. This evidence is backed up by data from studies of the (human) mirror neuron system using neuroimaging or TMS techniques, and behavioral experiments. Although the data acquire

  11. Motor neurone disease: an overview. (United States)

    Kent, Anna

    Motor neurone disease (MND) is a relatively rare, progressive and incurable neurological condition affecting patients' speech, mobility and respiratory function. Care of patients with MND is complex and involves various healthcare professionals and services. There is a need to discuss symptom management and promote palliative and end of life care from the point of diagnosis to ensure appropriate holistic care is provided.

  12. Performance of a Single Quantum Neuron

    Institute of Scientific and Technical Information of China (English)

    LIFei; ZHAOShengmei; ZHENGBaoyu


    Quantum neural network (QNN) is a promising area in the field of quantum computing and quantum information processing. A novel model for quantum neuron is described, a quantum learning algorithm is proposed and its convergence property is investigated. It has been shown, Quantum neuron (QN) has the same convergence property as Conventional neuron (CN) but can attain faster training than Conventional neuron. The computational power of the quantum neuron is also explored.Numerical and graphical results show that this single quantum neuron can implement the Walsh-Hadamard transformation, perform the XOR function unrealizable with a classical neuron and can eliminate the necessity of building a network of neurons to obtain nonlinear mapping.

  13. [The ontogeny of the mirror neuron system]. (United States)

    Myowa-Yamakoshi, Masako


    Abstract Humans utilize the mirror neuron system to understand and predict others' actions. However, the ontogeny of the mirror neuron system remains unknown. Whether mirror neuron function is an innate trait or whether mirror neurons acquire their sensorimotor matching properties ontogenetically remains to be clarified. In this paper, I review the ontogenetic theory of the mirror neuron system. I then discuss the functioning of the mirror neuron system in the context of social cognitive abilities, which are unique to humans. Recently, some researchers argue that it is too early to interpret the function of mirror neurons as an understanding of the underlying psychological states of others. They imply that such functioning would require inferential cognitive processes that are known to involve areas outside the mirror neuron system. Filling in this missing link may be the key to elucidating the unique ability of humans to understand others' actions.

  14. Effects of gabapentin on high voltage active calcium currents in injured dorsal root ganglion neurons in a rat model of neuropathic pain%加巴喷丁对神经病理性痛大鼠背根神经节神经元高电压激活钙电流的影响

    Institute of Scientific and Technical Information of China (English)

    陈晓东; 朱敏敏; 安珊珊; 王强; 陆亮; 孙芹; 肖杭; 徐建国; 段满林


    Objective To investigate the effect of gabapentin on high voltage active calcium currents in the injured dorsal root ganglion (DRG) neurons in a rat model of neuropathic pain.Methods Pathogen-free male SD rats aged 4-6 weeks were used in this study. The animals were anesthetized with intraperitoneal pentobarbital soclium 50 mg/kg. L_5 spinal nerve was ligated between DRG and sciatic nerve and cut distal to the ligature. The animals were decapitated on the 14th postoperative day. L_5 DRG was isolated and the neurons in the ganglion were enzymatically dissociated. The high voltage active calcium current was recorded using whole-cell patch-clamp technique.Results Gabapentin inhibited the peak calcium current in the injured DEG neurons. Peak calcium current was decreased by gabapentin 100 μmol/L and both activation and steady-state inactivation curve shifted to more hyperpolarized potentials. Conclusion Gabapentin can inhibit high voltage active in the injured DRG neurons in a rat model of neuropathic pain. The alteration in the inactivation of the electrophysiological properties may be involved in the mechanism.%目的 评价加巴喷丁对神经病理性痛大鼠背根神经节神经元高电压激活钙电流的影响.方法 雄性SD大鼠,周龄4~6周,采用结扎L_5脊神经的方法建立神经病理性痛模型.于术后14 d时采用酶消化法急性分离损伤侧L_5背根神经节神经元,采用全细胞膜片钳技术记录神经元高电压激活钙电流,记录加巴喷丁0.1、1、10、100、300 μmol/L(G_(1~5)组)作用下的钙电流,计算电流抑制率;并绘制100 μmol/L加巴喷丁作用下钙电流-电压曲线、钙通道激活曲线和稳态失活曲线.结果 与给药前比较,G_(1~5)组给药后钙电流均降低(P<0.05).给予100 μmol/L加巴喷丁后钙电流-电压曲线左移.与给药前比较,给予100 μmol/L加巴喷丁后钙通道激活曲线的半数激活电压和稳态失活曲线的半数失活电压降低(P<0.05),激

  15. Spiking neuron network Helmholtz machine. (United States)

    Sountsov, Pavel; Miller, Paul


    An increasing amount of behavioral and neurophysiological data suggests that the brain performs optimal (or near-optimal) probabilistic inference and learning during perception and other tasks. Although many machine learning algorithms exist that perform inference and learning in an optimal way, the complete description of how one of those algorithms (or a novel algorithm) can be implemented in the brain is currently incomplete. There have been many proposed solutions that address how neurons can perform optimal inference but the question of how synaptic plasticity can implement optimal learning is rarely addressed. This paper aims to unify the two fields of probabilistic inference and synaptic plasticity by using a neuronal network of realistic model spiking neurons to implement a well-studied computational model called the Helmholtz Machine. The Helmholtz Machine is amenable to neural implementation as the algorithm it uses to learn its parameters, called the wake-sleep algorithm, uses a local delta learning rule. Our spiking-neuron network implements both the delta rule and a small example of a Helmholtz machine. This neuronal network can learn an internal model of continuous-valued training data sets without supervision. The network can also perform inference on the learned internal models. We show how various biophysical features of the neural implementation constrain the parameters of the wake-sleep algorithm, such as the duration of the wake and sleep phases of learning and the minimal sample duration. We examine the deviations from optimal performance and tie them to the properties of the synaptic plasticity rule.

  16. Role of ser-237 in the substrate specificity of the carbapenem-hydrolyzing class A beta-lactamase Sme-1. (United States)

    Sougakoff, W; Naas, T; Nordmann, P; Collatz, E; Jarlier, V


    The role of the serine residue found at position 237 in the carbapenemase Sme-1 has been investigated by constructing a mutant in which Ser-237 was replaced by an alanine. The S237A mutant showed a catalytic behavior against penicillins and aztreonam very similar to that of Sme-1. By contrast, S237A was characterized by a reduced catalytic efficiency against cephems, such as cephalothin and cephaloridine. In addition, the weak activity of Sme-1 against the cephamycin cefoxitin was hardly detectable with the mutant enzyme. Finally, the Ser-237-->Ala mutation resulted in a marked decrease in catalytic activity against imipenem, showing that Ser-237 contributes to the carbapenemase activity of the class A beta-lactamase Sme-1.

  17. Acute renal infarction associated with homozygous methylenetetrahydrofolate reductase mutation C677T and IgA beta-2-glycoprotein antibodies. (United States)

    Vlachostergios, Panagiotis J; Dufresne, François


    Arterial thrombosis of the kidney(s) is a rare clinical entity usually presenting as a result of cardioembolic disease, though rare inherited hypercoagulable states have also been implicated. Within this context, both hyperhomocysteinemia triggered by a mutated methylenetetrahydrofolate reductase (MTHFR) gene product and the presence of antiphospholipid antibodies have been separately associated with arterial thrombotic events, including renal artery embolism. We present a case of combined homozygous MTHFR C677T mutation and IgA beta-2-glycoprotein antibody positivity resulting in acute renal infarction and previous silent myocardial infarction. An acute and otherwise unexplained thrombotic event of unusual location always warrants further investigation, which should include testing for hereditary thrombophilic disorders.

  18. BlastNeuron for Automated Comparison, Retrieval and Clustering of 3D Neuron Morphologies. (United States)

    Wan, Yinan; Long, Fuhui; Qu, Lei; Xiao, Hang; Hawrylycz, Michael; Myers, Eugene W; Peng, Hanchuan


    Characterizing the identity and types of neurons in the brain, as well as their associated function, requires a means of quantifying and comparing 3D neuron morphology. Presently, neuron comparison methods are based on statistics from neuronal morphology such as size and number of branches, which are not fully suitable for detecting local similarities and differences in the detailed structure. We developed BlastNeuron to compare neurons in terms of their global appearance, detailed arborization patterns, and topological similarity. BlastNeuron first compares and clusters 3D neuron reconstructions based on global morphology features and moment invariants, independent of their orientations, sizes, level of reconstruction and other variations. Subsequently, BlastNeuron performs local alignment between any pair of retrieved neurons via a tree-topology driven dynamic programming method. A 3D correspondence map can thus be generated at the resolution of single reconstruction nodes. We applied BlastNeuron to three datasets: (1) 10,000+ neuron reconstructions from a public morphology database, (2) 681 newly and manually reconstructed neurons, and (3) neurons reconstructions produced using several independent reconstruction methods. Our approach was able to accurately and efficiently retrieve morphologically and functionally similar neuron structures from large morphology database, identify the local common structures, and find clusters of neurons that share similarities in both morphology and molecular profiles.

  19. Cognition and behavior in motor neuron disease

    NARCIS (Netherlands)

    Raaphorst, J.


    Motor neuron disease (MND) is a devastating neurodegenerative disorder characterized by progressive motor neuron loss, leading to weakness of the muscles of arms and legs, bulbar and respiratory muscles. Depending on the involvement of the lower and the upper motor neuron, amyotrophic lateral sclero

  20. Oscillating from Neurosecretion to Multitasking Dopamine Neurons

    Directory of Open Access Journals (Sweden)

    David R. Grattan


    Full Text Available In this issue of Cell Reports, Stagkourakis et al. (2016 report that oscillating hypothalamic TIDA neurons, previously thought to be simple neurosecretory neurons controlling pituitary prolactin secretion, control dopamine output via autoregulatory mechanisms and thus could potentially regulate other physiologically important hypothalamic neuronal circuits.

  1. Studies Gain Insight into Neuronal Polarity

    Institute of Scientific and Technical Information of China (English)


    @@ A typical matured nerve cell (or neuron) has one axon and multiple dendrites. It receives information at the dendrites and sending signals to other neurons via the axon. Although scientists have discovered that this axon-dendrite polarity is a cardinal feature of neuronal morphology essential for information flow, they are still in the dark about the cause of this polarization.

  2. Neuronal networks: enhanced feedback feeds forward. (United States)

    Calabrese, Ronald L


    Modulatory projection neurons gate neuronal networks, such as those comprising motor central pattern generators; in turn, they receive feedback from the networks they gate. A recent study has shown that, in the crab stomatogastric ganglion, this feedback is also subject to modulation: the enhanced feedback feeds forward through the projection neurons to modify circuit output.

  3. Genetic and biochemical characterization of the chromosomal class A beta-lactamases of Raoultella (formerly Klebsiella) planticola and Raoultella ornithinolytica. (United States)

    Walckenaer, Estelle; Poirel, Laurent; Leflon-Guibout, Véronique; Nordmann, Patrice; Nicolas-Chanoine, Marie-Hélène


    Enterobacterial strains of Raoultella spp. display a penicillinase-related beta-lactam resistance pattern suggesting the presence of a chromosomal bla gene. From whole-cell DNA of Raoultella planticola strain ATCC 33531(T) and Raoultella ornithinolytica strain ATCC 31898(T), bla genes were cloned and expressed into Escherichia coli. Each gene encoded an Ambler class A beta-lactamase, named PLA-1 and ORN-1 for R. planticola and R. ornithinolytica, respectively. These beta-lactamases (291 amino acids), with the same pI value of 7.8, had a shared amino acid identity of 94%, 37 to 47% identity with the majority of the chromosome-encoded class A beta-lactamases previously described for Enterobacteriaceae, and 66 to 69% identity with the two beta-lactamases LEN-1 and SHV-1 from Klebsiella pneumoniae. However, the highest identity percentage (69 to 71%) was found with the plasmid-mediated beta-lactamase TEM-1. PLA-1, which displayed very strong hydrolytic activity against penicillins, also displayed significant hydrolytic activity against cefepime and, to a lesser extent, against cefotaxime and aztreonam, but there was no hydrolytic activity against ceftazidime. Such a substrate profile suggests that the Raoultella beta-lactamases PLA-1 and ORN-1 should be classified into the group 2be of the beta-lactamase classification of K. Bush, G. A. Jacoby, and A. A. Medeiros (Antimicrob. Agents Chemother. 39:1211-1233, 1995). The highly homologous regions upstream of the bla(PLA-1A) and bla(ORN-1A) genes comprised a nucleotide sequence identical to the -35 region and another one very close to the -10 region of the bla(LEN-1) gene. From now on, as the bla gene sequences of the most frequent Raoultella and Klebsiella species are available, the bla gene amplification method can be used to differentiate these species from each other, which the biochemical tests currently carried out in the clinical laboratory are unable to do.

  4. A beta-lactam antibiotic dampens excitotoxic inflammatory CNS damage in a mouse model of multiple sclerosis.

    Directory of Open Access Journals (Sweden)

    Nico Melzer

    Full Text Available In multiple sclerosis (MS and its animal model experimental autoimmune encephalomyelitis (EAE, impairment of glial "Excitatory Amino Acid Transporters" (EAATs together with an excess glutamate-release by invading immune cells causes excitotoxic damage of the central nervous system (CNS. In order to identify pathways to dampen excitotoxic inflammatory CNS damage, we assessed the effects of a beta-lactam antibiotic, ceftriaxone, reported to enhance expression of glial EAAT2, in "Myelin Oligodendrocyte Glycoprotein" (MOG-induced EAE. Ceftriaxone profoundly ameliorated the clinical course of murine MOG-induced EAE both under preventive and therapeutic regimens. However, ceftriaxone had impact neither on EAAT2 protein expression levels in several brain areas, nor on the radioactive glutamate uptake capacity in a mixed primary glial cell-culture and the glutamate-induced uptake currents in a mammalian cell line mediated by EAAT2. Moreover, the clinical effect of ceftriaxone was preserved in the presence of the EAAT2-specific transport inhibitor, dihydrokainate, while dihydrokainate alone caused an aggravated EAE course. This demonstrates the need for sufficient glial glutamate uptake upon an excitotoxic autoimmune inflammatory challenge of the CNS and a molecular target of ceftriaxone other than the glutamate transporter. Ceftriaxone treatment indirectly hampered T cell proliferation and proinflammatory INFgamma and IL17 secretion through modulation of myelin-antigen presentation by antigen-presenting cells (APCs e.g. dendritic cells (DCs and reduced T cell migration into the CNS in vivo. Taken together, we demonstrate, that a beta-lactam antibiotic attenuates disease course and severity in a model of autoimmune CNS inflammation. The mechanisms are reduction of T cell activation by modulation of cellular antigen-presentation and impairment of antigen-specific T cell migration into the CNS rather than or modulation of central glutamate homeostasis.

  5. Coherence resonance in globally coupled neuronal networks with different neuron numbers

    Institute of Scientific and Technical Information of China (English)

    Ning Wei-Lian; Zhang Zheng-Zhen; Zeng Shang-You; Luo Xiao-Shu; Hu Jin-Lin; Zeng Shao-Wen; Qiu Yi; Wu Hui-Si


    Because a brain consists of tremendous neuronal networks with different neuron numbers ranging from tens to tens of thousands,we study the coherence resonance due to ion channel noises in globally coupled neuronal networks with different neuron numbers.We confirm that for all neuronal networks with different neuron numbers there exist the array enhanced coherence resonance and the optimal synaptic conductance to cause the maximal spiking coherence.Furthermoremore,the enhancement effects of coupling on spiking coherence and on optimal synaptic conductance are almost the same,regardless of the neuron numbers in the neuronal networks.Therefore for all the neuronal networks with different neuron numbers in the brain,relative weak synaptic conductance (0.1 mS/cm2) is sufficient to induce the maximal spiking coherence and the best sub-threshold signal encoding.

  6. What we know currently about mirror neurons. (United States)

    Kilner, J M; Lemon, R N


    Mirror neurons were discovered over twenty years ago in the ventral premotor region F5 of the macaque monkey. Since their discovery much has been written about these neurons, both in the scientific literature and in the popular press. They have been proposed to be the neuronal substrate underlying a vast array of different functions. Indeed so much has been written about mirror neurons that last year they were referred to, rightly or wrongly, as "The most hyped concept in neuroscience". Here we try to cut through some of this hyperbole and review what is currently known (and not known) about mirror neurons.

  7. Mechanical and thermal hyperalgesia and ectopic neuronal discharge after chronic compression of dorsal root ganglia. (United States)

    Song, X J; Hu, S J; Greenquist, K W; Zhang, J M; LaMotte, R H


    Chronic compression of the dorsal root ganglion (CCD) was produced in adult rats by implanting a stainless steel rod unilaterally into the intervertebral foramen, one rod at L(4) and another at L(5). Two additional groups of rats received either a sham surgery or an acute injury consisting of a transient compression of the ganglion. Withdrawal of the hindpaw was used as evidence of a nocifensive response to mechanical and thermal stimulation of the plantar surface. In addition, extracellular electrophysiological recordings of spontaneous discharges were obtained from dorsal root fibers of formerly compressed ganglia using an in vitro nerve-DRG-dorsal root preparation. The mean threshold force of punctate indentation and the mean threshold temperature of heating required to elicit a 50% incidence of foot withdrawal ipsilateral to the CCD were significantly lower than preoperative values throughout the 35 days of postoperative testing. The number of foot withdrawals ipsilateral to the CCD during a 20-min contact with a temperature-controlled floor was significantly increased over preoperative values throughout postoperative testing when the floor was 4 degrees C (hyperalgesia) and, to a lesser extent, when it was 30 degrees C (spontaneous pain). Stroking the foot with a cotton wisp never elicited a reflex withdrawal before surgery but did so in most rats tested ipsilateral to the CCD during the first 2 postoperative weeks. In contrast, the CCD produced no changes in responses to mechanical or thermal stimuli on the contralateral foot. The sham operation and acute injury produced no change in behavior other than slight, mechanical hyperalgesia for approximately 1 day, ipsilateral to the acute injury. Ectopic spontaneous discharges generated within the chronically compressed ganglion and, occurring in the absence of blood-borne chemicals and without an intact sympathetic nervous system, were recorded from neurons with intact, conducting, myelinated or unmyelinated

  8. Stiff substrates enhance cultured neuronal network activity. (United States)

    Zhang, Quan-You; Zhang, Yan-Yan; Xie, Jing; Li, Chen-Xu; Chen, Wei-Yi; Liu, Bai-Lin; Wu, Xiao-an; Li, Shu-Na; Huo, Bo; Jiang, Lin-Hua; Zhao, Hu-Cheng


    The mechanical property of extracellular matrix and cell-supporting substrates is known to modulate neuronal growth, differentiation, extension and branching. Here we show that substrate stiffness is an important microenvironmental cue, to which mouse hippocampal neurons respond and integrate into synapse formation and transmission in cultured neuronal network. Hippocampal neurons were cultured on polydimethylsiloxane substrates fabricated to have similar surface properties but a 10-fold difference in Young's modulus. Voltage-gated Ca(2+) channel currents determined by patch-clamp recording were greater in neurons on stiff substrates than on soft substrates. Ca(2+) oscillations in cultured neuronal network monitored using time-lapse single cell imaging increased in both amplitude and frequency among neurons on stiff substrates. Consistently, synaptic connectivity recorded by paired recording was enhanced between neurons on stiff substrates. Furthermore, spontaneous excitatory postsynaptic activity became greater and more frequent in neurons on stiff substrates. Evoked excitatory transmitter release and excitatory postsynaptic currents also were heightened at synapses between neurons on stiff substrates. Taken together, our results provide compelling evidence to show that substrate stiffness is an important biophysical factor modulating synapse connectivity and transmission in cultured hippocampal neuronal network. Such information is useful in designing instructive scaffolds or supporting substrates for neural tissue engineering.

  9. Control of Neuronal Network in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Rahul Badhwar

    Full Text Available Caenorhabditis elegans, a soil dwelling nematode, is evolutionarily rudimentary and contains only ∼ 300 neurons which are connected to each other via chemical synapses and gap junctions. This structural connectivity can be perceived as nodes and edges of a graph. Controlling complex networked systems (such as nervous system has been an area of excitement for mankind. Various methods have been developed to identify specific brain regions, which when controlled by external input can lead to achievement of control over the state of the system. But in case of neuronal connectivity network the properties of neurons identified as driver nodes is of much importance because nervous system can produce a variety of states (behaviour of the animal. Hence to gain insight on the type of control achieved in nervous system we implemented the notion of structural control from graph theory to C. elegans neuronal network. We identified 'driver neurons' which can provide full control over the network. We studied phenotypic properties of these neurons which are referred to as 'phenoframe' as well as the 'genoframe' which represents their genetic correlates. We find that the driver neurons are primarily motor neurons located in the ventral nerve cord and contribute to biological reproduction of the animal. Identification of driver neurons and its characterization adds a new dimension in controllability of C. elegans neuronal network. This study suggests the importance of driver neurons and their utility to control the behaviour of the organism.

  10. Neuronal autophagy in cerebral ischemia

    Institute of Scientific and Technical Information of China (English)

    Feng Xu; Jin-Hua Gu; Zheng-Hong Qin


    Autophagy has evolved as a conserved process for the bulk degradation and recycling of cytosolic components,such as long-lived proteins and organelles.In neurons,autophagy is important for homeostasis and protein quality control and is maintained at relatively low levels under normal conditions,while it is upregulated in response to pathophysiological conditions,such as cerebral ischemic injury.However,the role of autophagy is more complex.It depends on age or brain maturity,region,severity of insult,and the stage of ischemia.Whether autophagy plays a beneficial or a detrimental role in cerebral ischemia depends on various pathological conditions.In this review,we elucidate the role of neuronal autophagy in cerebral ischemia.

  11. Neuronal Analogues of Conditioning Paradigms (United States)


    Although the mechanisms of interneuronal communication have been well established, the changes underlying most forms of learning have thus far eluded...stimulating electrodes on one of the connectives was adjusted so as to produce a small excitatory postsynaptic potential ( EPSP ) in the impaled cell...two stimuli would constitute a neuronal analogue of conditioning by producing an increased EPSP in response to the test stimulus alone. If so, then

  12. Neuronal mechanism for neuropathic pain


    Zhuo Min


    Abstract Among different forms of persistent pain, neuropathic pain presents as a most difficult task for basic researchers and clinicians. Despite recent rapid development of neuroscience and modern techniques related to drug discovery, effective drugs based on clear basic mechanisms are still lacking. Here, I will review the basic neuronal mechanisms that maybe involved in neuropathic pain. I will present the problem of neuropathic pain as a rather difficult task for neuroscientists, and we...

  13. Selective serotonergic excitation of callosal projection neurons

    Directory of Open Access Journals (Sweden)

    Daniel eAvesar


    Full Text Available Serotonin (5-HT acting as a neurotransmitter in the cerebral cortex is critical for cognitive function, yet how 5-HT regulates information processing in cortical circuits is not well understood. We tested the serotonergic responsiveness of layer 5 pyramidal neurons (L5PNs of the mouse medial prefrontal cortex (mPFC, and found 3 distinct response types: long-lasting 5-HT1A (1A receptor-dependent inhibitory responses (84% of L5PNs, 5-HT2A (2A receptor-dependent excitatory responses (9%, and biphasic responses in which 2A-dependent excitation followed brief inhibition (5%. Relative to 5-HT-inhibited neurons, those excited by 5-HT had physiological properties characteristic of callosal/commissural (COM neurons that project to the contralateral cortex. We tested whether serotonergic responses in cortical pyramidal neurons are correlated with their axonal projection pattern using retrograde fluorescent labeling of COM and corticopontine-projecting (CPn neurons. 5-HT generated excitatory or biphasic responses in all 5-HT-responsive layer 5 COM neurons. Conversely, CPn neurons were universally inhibited by 5-HT. Serotonergic excitation of COM neurons was blocked by the 2A antagonist MDL 11939, while serotonergic inhibition of CPn neurons was blocked by the 1A antagonist WAY 100635, confirming a role for these two receptor subtypes in regulating pyramidal neuron activity. Selective serotonergic excitation of COM neurons was not layer-specific, as COM neurons in layer 2/3 were also selectively excited by 5-HT relative to their non-labeled pyramidal neuron neighbors. Because neocortical 2A receptors are implicated in the etiology and pathophysiology of schizophrenia, we propose that COM neurons may represent a novel cellular target for intervention in psychiatric disease.

  14. Neuronal responses to physiological stress

    Directory of Open Access Journals (Sweden)

    Konstantinos eKagias


    Full Text Available Physiological stress can be defined as any external or internal condition that challenges the homeostasis of a cell or an organism. Physiological stress can be divided into three different aspects: environmental stress, intrinsic developmental stress and aging. Throughout life all living organisms are challenged by changes in the environment. Fluctuations in oxygen levels, temperature and redox state for example, trigger molecular events that enable an organism to adapt, survive and reproduce. In addition to external stressors, organisms experience stress associated with morphogenesis and changes in inner chemistry during normal development. For example, conditions such as intrinsic hypoxia and oxidative stress, which result from an increase in tissue mass, have to be confronted by developing embryos in order to complete their development. Finally, organisms face the challenge of stochastic accumulation of molecular damage during aging that results in decline and eventual death. Studies have shown that the nervous system plays a pivotal role in responding to stress. Neurons not only receive and process information from the environment but also actively respond to various stresses to promote survival. These responses include changes in the expression of molecules such as transcription factors and microRNAs that regulate stress resistance and adaptation. Moreover, both intrinsic and extrinsic stresses have a tremendous impact on neuronal development and maintenance with implications in many diseases. Here, we review the responses of neurons to various physiological stressors at the molecular and cellular level.

  15. Effects of simulated weightlessness on Nissl body morphology and GDNF in DRG of male rats%模拟失重对雄性大鼠背根神经节尼氏小体形态和胶质细胞源性神经营养因子的影响

    Institute of Scientific and Technical Information of China (English)

    任宁涛; 崔赓; 张恒; 李洁; 雷伟; 刘宁; 毕龙; 吴子祥; 张然; 张永刚


    Objective To investigate the effect of simulated weightlessness on dorsal root ganglia (DRG) and GDNF in rat model. Methods Eighty male Sprague-Dawley rats were randomly divided into HU group (n=40) and normal control (NC) group (n=40). The experiment lasted for 4 weeks, then L5 DRG was excised, toluidine blue staining was used to detect the changes of nissl body morphology, and GDNF was detected using immunohistochemistry method. GDNF protein expression was measured by Western-blot and GDNF mRNA expression was measured by RT-PCR.Results Nissl body staining showed that, compared with NC group, nissl bodies were stained light, smaller and scattering distribution in HU group. Immunohistochemistry revealed that the number of GDNF and IOD value reduced significantly in HU group (P<0.05). Western-blot showed that GDNF protein expression in HU group were significantly lower than NC group (P<0.05). mRNA expression of GDNF decreased significantly in HU group (P<0.05). Conclusion Four weeks of stimulated weightlessness can cause damaged changes in DRG nissl body morphology and reduction of the number, protein expression and mRNA expression of GDNF, which suggests that simulated weightlessness can cause damage changes in rat dorsal root ganglion.%目的:探讨模拟失重对背根神经节(dorsal root ganglia,DRG)及胶质细胞源性神经营养因子(glial cell line-derived neurotrophic factor,GDNF)的影响。方法健康雄性SD大鼠80只,随机分为尾部悬吊(HU)组(n=40)和正常对照(NC)组(n=40),4周后处死各组大鼠,取腰5背根神经节,甲苯氨兰染色观察背根神经节内尼氏小体变化,免疫组化观察GDNF的变化, Western-blot方法检测GDNF的蛋白表达,实时PCR检测GDNF mRNA表达情况。结果与NC组相比,HU组尼氏体染色浅,尼氏体变小,弥散分布。免疫组化结果显示,与NC组比较,HU组GDNF量及积分光密度(integral optical density,IOD)值减少(P<0.05)。Western-blot结果

  16. Neuregulin-mediated ErbB3 signaling is required for formation of zebrafish dorsal root ganglion neurons


    Honjo, Yasuko; Kniss, Jonathan; Eisen, Judith S


    Dorsal root ganglia (DRGs) arise from trunk neural crest cells that emerge from the dorsal neuroepithelium and coalesce into segmental streams that migrate ventrally along the developing somites. Proper formation of DRGs involves not only normal trunk neural crest migration, but also the ability of DRG progenitors to pause at a particular target location where they can receive DRG-promoting signals. In mammalian embryos a receptor tyrosine kinase proto-oncogene, ErbB3, is required for proper ...

  17. NBLAST: Rapid, Sensitive Comparison of Neuronal Structure and Construction of Neuron Family Databases. (United States)

    Costa, Marta; Manton, James D; Ostrovsky, Aaron D; Prohaska, Steffen; Jefferis, Gregory S X E


    Neural circuit mapping is generating datasets of tens of thousands of labeled neurons. New computational tools are needed to search and organize these data. We present NBLAST, a sensitive and rapid algorithm, for measuring pairwise neuronal similarity. NBLAST considers both position and local geometry, decomposing neurons into short segments; matched segments are scored using a probabilistic scoring matrix defined by statistics of matches and non-matches. We validated NBLAST on a published dataset of 16,129 single Drosophila neurons. NBLAST can distinguish neuronal types down to the finest level (single identified neurons) without a priori information. Cluster analysis of extensively studied neuronal classes identified new types and unreported topographical features. Fully automated clustering organized the validation dataset into 1,052 clusters, many of which map onto previously described neuronal types. NBLAST supports additional query types, including searching neurons against transgene expression patterns. Finally, we show that NBLAST is effective with data from other invertebrates and zebrafish. VIDEO ABSTRACT.

  18. Femtosecond laser-induced stimulation of a single neuron in a neuronal network (United States)

    Hosokawa, Chie; Sakamoto, Yasutaka; Kudoh, Suguru N.; Hosokawa, Yoichiroh; Taguchi, Takahisa


    We demonstrated the stimulation of neurons at a single-cell level in cultured neuronal network by a focused femtosecond laser. When the femtosecond laser was focused on a neuron loaded with a fluorescent calcium indicator, the fluorescence intensity immediately increased at the laser spot, suggesting that intracellular Ca2+ increases in the neuronal cell due to the femtosecond laser irradiation. The probability of Ca2+ elevation at the laser spot depended on the average laser power, irradiation time, and position of the focal point along the optical axis, indicating that the femtosecond laser activates neurons because of multiphoton absorption. Moreover, after laser irradiation of a single neuron cultured on multielectrode arrays, the evoked electrical activity of the neurons was demonstrated by electrophysiological systems, which concluded that the focused femtosecond laser could achieve stimulating a single neuron in a neuronal network with high spatial and temporal resolution.

  19. Results on a Binding Neuron Model and Their Implications for Modified Hourglass Model for Neuronal Network

    Directory of Open Access Journals (Sweden)

    Viswanathan Arunachalam


    Full Text Available The classical models of single neuron like Hodgkin-Huxley point neuron or leaky integrate and fire neuron assume the influence of postsynaptic potentials to last till the neuron fires. Vidybida (2008 in a refreshing departure has proposed models for binding neurons in which the trace of an input is remembered only for a finite fixed period of time after which it is forgotten. The binding neurons conform to the behaviour of real neurons and are applicable in constructing fast recurrent networks for computer modeling. This paper develops explicitly several useful results for a binding neuron like the firing time distribution and other statistical characteristics. We also discuss the applicability of the developed results in constructing a modified hourglass network model in which there are interconnected neurons with excitatory as well as inhibitory inputs. Limited simulation results of the hourglass network are presented.

  20. Glutamate neurons are intermixed with midbrain dopamine neurons in nonhuman primates and humans (United States)

    Root, David H.; Wang, Hui-Ling; Liu, Bing; Barker, David J.; Mód, László; Szocsics, Péter; Silva, Afonso C.; Maglóczky, Zsófia; Morales, Marisela


    The rodent ventral tegmental area (VTA) and substantia nigra pars compacta (SNC) contain dopamine neurons intermixed with glutamate neurons (expressing vesicular glutamate transporter 2; VGluT2), which play roles in reward and aversion. However, identifying the neuronal compositions of the VTA and SNC in higher mammals has remained challenging. Here, we revealed VGluT2 neurons within the VTA and SNC of nonhuman primates and humans by simultaneous detection of VGluT2 mRNA and tyrosine hydroxylase (TH; for identification of dopamine neurons). We found that several VTA subdivisions share similar cellular compositions in nonhuman primates and humans; their rostral linear nuclei have a high prevalence of VGluT2 neurons lacking TH; their paranigral and parabrachial pigmented nuclei have mostly TH neurons, and their parabrachial pigmented nuclei have dual VGluT2-TH neurons. Within nonhuman primates and humans SNC, the vast majority of neurons are TH neurons but VGluT2 neurons were detected in the pars lateralis subdivision. The demonstration that midbrain dopamine neurons are intermixed with glutamate or glutamate-dopamine neurons from rodents to humans offers new opportunities for translational studies towards analyzing the roles that each of these neurons play in human behavior and in midbrain-associated illnesses such as addiction, depression, schizophrenia, and Parkinson’s disease. PMID:27477243

  1. Microwave-assisted click polymerization for the synthesis of A beta(16-22) cyclic oligomers and their self-assembly into polymorphous aggregates

    NARCIS (Netherlands)

    Elgersma, R.C.; van Dijk, M.; Dechesne, A.C.; van Nostrum, C.F.; Hennink, W.E.; Rijkers, D.T.S.; Liskamp, R.M.J.


    We report on the design, synthesis, and structural analysis of cyclic oligomers with an amyloidogenic peptide sequence as the repeating unit to obtain novel self-assembling bionanomaterials. The peptide was derived from the Alzheimer A beta(16-22) sequence since its strong tendency to form antiparal


    NARCIS (Netherlands)



    Radiographs of hand and hip joints of 15 hemodialysis patients taken annually over at least 15 years were evaluated in this retrospective study. We looked for signs of A beta(2),M-amyloidosis such as lucencies, erosions, and soft tissue swelling. The femoral head-soft tissue distance (FHSTD) was use

  3. Salvianolic acid B, an antioxidant from Salvia miltiorrhiza, prevents A beta(25-35)-induced reduction in BPRP in PC12 cells

    NARCIS (Netherlands)

    Lin, Yan-Hua; Liu, Ai-Hua; Wu, Hong-Li; Westenbroek, Christel; Song, Qian-Liu; Yu, He-Ming; Ter Horst, Gert J.; Li, Xue-Jun; Li, Xiang-yi


    Several lines of evidence support that beta-amyloid (A beta)-induced neurotoxicity is mediated through the generation of reactive oxygen species (ROS) and elevation of intracellular calcium. Salvianolic acid B (Sal B), the major and most active anti-oxidant from Salvia miltiorrhiza. protects diverse

  4. Effect of cocoa butter replacement with a beta-glucan-rich hydrocolloid (C-trim30) on the rheological and tribological properties of chocolates (United States)

    Cocoa butter in chocolates was replaced with C-trim30 (5, 10, 15% by weight), a beta-glucan-rich hydrocolloid containing elevated amount of beta-glucan (32%, db). Then, the effects of the C-trim30 on the rheological, tribological, and textural properties of chocolates were investigated. The viscos...

  5. The Venom of the Spider Selenocosmia Jiafu Contains Various Neurotoxins Acting on Voltage-Gated Ion Channels in Rat Dorsal Root Ganglion Neurons

    Directory of Open Access Journals (Sweden)

    Zhaotun Hu


    Full Text Available Selenocosmia jiafu is a medium-sized theraphosid spider and an attractive source of venom, because it can be bred in captivity and it produces large amounts of venom. We performed reversed-phase high-performance liquid chromatography (RP-HPLC and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS analyses and showed that S. jiafu venom contains hundreds of peptides with a predominant mass of 3000–4500 Da. Patch clamp analyses indicated that the venom could inhibit voltage-gated Na+, K+ and Ca2+ channels in rat dorsal root ganglion (DRG neurons. The venom exhibited inhibitory effects on tetrodotoxin-resistant (TTX-R Na+ currents and T-type Ca2+ currents, suggesting the presence of antagonists to both channel types and providing a valuable tool for the investigation of these channels and for drug development. Intra-abdominal injection of the venom had severe toxic effects on cockroaches and caused death at higher concentrations. The LD50 was 84.24 μg/g of body weight in the cockroach. However, no visible symptoms or behavioral changes were detected after intraperitoneal injection of the venom into mice even at doses up to 10 mg/kg body weight. Our results provide a basis for further case-by-case investigations of peptide toxins from this venom.

  6. The venom of the fishing spider Dolomedes sulfurous contains various neurotoxins acting on voltage-activated ion channels in rat dorsal root ganglion neurons. (United States)

    Wang, Hengyun; Zhang, Fan; Li, Dan; Xu, Shiyan; He, Juan; Yu, Hai; Li, Jiayan; Liu, Zhonghua; Liang, Songping


    Dolomedes sulfurous is a venomous spider distributed in the south of China and characterized with feeding on fish. The venom exhibits great diversity and contains hundreds of peptides as revealed by off-line RP-HPLC/MALDI-TOF-MS analysis. The venom peptides followed a triple-modal distribution, with 40.7% of peptides falling in the mass range of 1000-3000 Da, 25.6% peptides in the 7000-9000 Da range and 23.5% peptides in the 3000-5000 Da range. This distribution modal is rather different from these of peptides from other spider venoms analyzed. The venom could inhibit voltage-activated Na(+), K(+) and Ca(2+) channels in rat DRG neurons as revealed by voltage-clamp analysis. Significantly, the venom exhibited inhibitory effects on TTX-R Na(+) and T-type Ca(2+) currents, suggesting that there exist both channel antagonists which might be valuable tools for investigation of both channels and drug development. Additionally, intrathoracically injection of venom could cause serve neurotoxic effects on zebrafish and death at higher concentrations. The LD50 value was calculated to be 28.8 μg/g body weight. Our results indicated that the venom of D. sulfurous contain diverse neurotoxins which serve to capture prey. Intensive studies will be necessary to investigate the structures and functions of specific peptides of the venom in the future.

  7. The venom of the spider Selenocosmia jiafu contains various neurotoxins acting on voltage-gated ion channels in rat dorsal root ganglion neurons. (United States)

    Hu, Zhaotun; Zhou, Xi; Chen, Jia; Tang, Cheng; Xiao, Zhen; Ying, Dazhong; Liu, Zhonghua; Liang, Songping


    Selenocosmia jiafu is a medium-sized theraphosid spider and an attractive source of venom, because it can be bred in captivity and it produces large amounts of venom. We performed reversed-phase high-performance liquid chromatography (RP-HPLC) and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analyses and showed that S. jiafu venom contains hundreds of peptides with a predominant mass of 3000-4500 Da. Patch clamp analyses indicated that the venom could inhibit voltage-gated Na+, K+ and Ca2+ channels in rat dorsal root ganglion (DRG) neurons. The venom exhibited inhibitory effects on tetrodotoxin-resistant (TTX-R) Na+ currents and T-type Ca2+ currents, suggesting the presence of antagonists to both channel types and providing a valuable tool for the investigation of these channels and for drug development. Intra-abdominal injection of the venom had severe toxic effects on cockroaches and caused death at higher concentrations. The LD50 was 84.24 μg/g of body weight in the cockroach. However, no visible symptoms or behavioral changes were detected after intraperitoneal injection of the venom into mice even at doses up to 10 mg/kg body weight. Our results provide a basis for further case-by-case investigations of peptide toxins from this venom.

  8. Delayed neuronal recovery and neuronal death in rat hippocampus following severe cerebral ischemia: possible relationship to abnormalities in neuronal processes. (United States)

    Petito, C K; Pulsinelli, W A


    Mechanisms involved in the postischemic delay in neuronal recovery or death in rat hippocampus were evaluated by light and electron microscopy at 3, 15, 30, and 120 min and 24, 36, 48, and 72 h following severe cerebral ischemia that was produced by permanent occlusion of the vertebral arteries and 30-min occlusion of the common carotid arteries. During the early postischemic period, neurons in the Ca1 and Ca3 regions both showed transient mitochondrial swelling followed by the disaggregation of polyribosomes, decrease in rough endoplasmic reticulum (RER), loss of Golgi apparatus (GA) cisterns, and decrease in GA vesicles . Recovery of these organelles in Ca3 neurons was first noted between 24 and 36 h and was accompanied by a marked proliferation of smooth endoplasmic reticulum (SER). Many Ca1 neurons initially recovered between 24 and 36 h, but subsequent cell death at 48-72 h was often preceded by peripheral chromatolysis, constriction and shrinkage of the proximal dendrites, and cytoplasmic dilatation that was continuous with focal expansion of RER cisterns. Because SER accumulates in resistant Ca3 neurons and proximal neuronal processes are damaged in vulnerable Ca1 neurons, we hypothesize that delayed cell recovery or death in vulnerable and resistant postischemic hippocampal neurons is related to abnormalities in neuronal processes.

  9. Mechanotransduction molecules in the plant gravisensory response: amyloplast/statolith membranes contain a beta 1 integrin-like protein (United States)

    Lynch, T. M.; Lintilhac, P. M.; Domozych, D.


    It has been hypothesized that the sedimentation of amyloplasts within root cap cells is the primary event in the plant gravisensory-signal transduction cascade. Statolith sedimentation, with its ability to generate weighty mechanical signals, is a legitimate means for organisms to discriminate the direction of the gravity vector. However, it has been demonstrated that starchless mutants with reduced statolith densities maintain some ability to sense gravity, calling into question the statolith sedimentation hypothesis. Here we report on the presence of a beta 1 integrin-like protein localized inside amyloplasts of tobacco NT-1 suspension culture, callus cells, and whole-root caps. Two different antibodies to the beta 1 integrin, one to the cytoplasmic domain and one to the extracellular domain, localize in the vicinity of the starch grains within amyloplasts of NT-1. Biochemical data reveals a 110-kDa protein immunoprecipitated from membrane fractions of NT-1 suspension culture indicating size homology to known beta 1 integrin in animals. This study provides the first direct evidence for the possibility of integrin-mediated signal transduction in the perception of gravity by higher plants. An integrin-mediated pathway, initiated by starch grain sedimentation within the amyloplast, may provide the signal amplification necessary to explain the gravitropic response in starch-depleted cultivars.

  10. Association between group A beta-haemolytic streptococci and vulvovaginitis in adult women: a case-control study. (United States)

    Bruins, M J; Damoiseaux, R A M J; Ruijs, G J H M


    Guidelines for the management of vaginal discharge mention Candida albicans, Trichomonas vaginalis, bacterial vaginosis, Chlamydia trachomatis and Neisseria gonorrhoeae as causes and do not recommend full microbiological culture. The role of non-group B beta-haemolytic streptococci in vaginal cultures is unclear, except for group A streptococci that are known to cause vulvovaginitis in children. In a case-control study, we investigated the association between non-group B beta-haemolytic streptococci and vulvovaginitis in adult women. Cases were women with recurrent vaginal discharge from whom a sample was cultured. Controls were asymptomatic women who consented to submitting a vaginal swab. Group A streptococci were isolated from 49 (4.9%) of 1,010 cases and not from the 206 controls (P < 0.01). Isolation rates of group C, F and G streptococci were low and did not differ statistically between cases and controls. Group A beta-haemolytic streptococci are associated with vaginal discharge in adult women. The other non-group B streptococci require more study. For the adequate management of vaginal discharge, culturing is necessary if initial treatment fails. Guidelines should be amended according to these results.

  11. Late-onset Rash in Patients with Group A Beta-hemolytic Streptococcal Pharyngitis Treated with Amoxicillin (United States)


    We observed late-onset rashes in patients with group A beta-hemolytic streptococcal (GAS) pharyngitis. Of 1028 patients with GAS pharyngitis, which was principally treated with amoxicillin, we evaluated those who developed a late-onset rash and excluded those with scarlet fever alone. Twenty-one patients developed a rash (2.0%, 95% confidence interval, 1.3-3.1%), 7 to 20 days (median, 8 days) after GAS pharyngitis onset. The rashes were characterized by maculopapules, which increased in size with coalescence and some developing into plaques, with a symmetrical distribution with a propensity for the extremities, including the palms and soles. The clinical courses of the patients were good, and the rashes subsided within 14 days. A non-immediate reaction to β-lactams, which usually manifests as a maculopapular rash, is a possible cause in our patients, however, repeated courses of amoxicillin in 3 patients did not induce the rash. The underlying mechanism of the late-onset rash after GAS pharyngitis with amoxicillin treatment remains unclear. PMID:26734124

  12. Late-onset rash in patients with group A beta-hemolytic streptococcal pharyngitis treated with amoxicillin

    Directory of Open Access Journals (Sweden)

    Masahiko Kimura


    Full Text Available We observed late-onset rashes in patients with group A beta-hemolytic streptococcal (GAS pharyngitis. Of 1028 patients with GAS pharyngitis, which was principally treated with amoxicillin, we evaluated those who developed a late-onset rash and excluded those with scarlet fever alone. Twenty-one patients developed a rash (2.0%, 95% confidence interval, 1.3- 3.1%, 7 to 20 days (median, 8 days after GAS pharyngitis onset. The rashes were characterized by maculopapules, which increased in size with coalescence and some developing into plaques, with a symmetrical distribution with a propensity for the extremities, including the palms and soles. The clinical courses of the patients were good, and the rashes subsided within 14 days. A non-immediate reaction to β-lactams, which usually manifests as a maculopapular rash, is a possible cause in our patients, however, repeated courses of amoxicillin in 3 patients did not induce the rash. The underlying mechanism of the late-onset rash after GAS pharyngitis with amoxicillin treatment remains unclear.

  13. Stellar modelling of Spica, a high-mass spectroscopic binary with a beta Cep variable primary component

    CERN Document Server

    Tkachenko, A; Aerts, C; Pavlovski, K; Papics, P I; Zwintz, K; Cameron, C; Walker, G A H; Kuschnig, R; Degroote, P; Debosscher, J; Moravveji, E; Kolbas, V; Guenther, D B; Moffat, A F J; Rowe, J F; Rucinski, S M; Sasselov, D; Weiss, W W


    Binary stars provide a valuable test of stellar structure and evolution, because the masses of the individual stellar components can be derived with high accuracy and in a model-independent way. In this work, we study Spica, an eccentric double-lined spectroscopic binary system with a beta Cep type variable primary component. We use state-of-the-art modelling tools to determine accurate orbital elements of the binary system and atmospheric parameters of both stellar components. We interpret the short-period variability intrinsic to the primary component, detected on top of the orbital motion both in the photometric and spectroscopic data. The non-LTE based spectrum analysis reveals two stars of similar atmospheric chemical composition consistent with the present day cosmic abundance standard defined by Nieva&Przybilla (2012). The masses and radii of the stars are found to be 11.43+/-1.15 M_sun and 7.21+/-0.75 M_sun, and 7.47+/-0.54 R_sun and 3.74+/-0.53 R_sun for the primary and secondary, respectively. W...

  14. Structure-Based Design of Potent and Ligand-Efficient Inhibitors of CTX-M Class A [beta]-Lactamase

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Derek A.; Jaishankar, Priyadarshini; Larson, Wayne; Smith, Emmanuel; Liu, Guoqing; Beyrouthy, Racha; Bonnet, Richard; Renslo, Adam R.; Chen, Yu (USF); (UCSF); (Clermont)


    The emergence of CTX-M class A extended-spectrum {beta}-lactamases poses a serious health threat to the public. We have applied structure-based design to improve the potency of a novel noncovalent tetrazole-containing CTX-M inhibitor (K{sub i} = 21 {mu}M) more than 200-fold via structural modifications targeting two binding hot spots, a hydrophobic shelf formed by Pro167 and a polar site anchored by Asp240. Functional groups contacting each binding hot spot independently in initial designs were later combined to produce analogues with submicromolar potencies, including 6-trifluoromethyl-3H-benzoimidazole-4-carboxylic acid [3-(1H-tetrazol-5-yl)-phenyl]-amide, which had a K{sub i} value of 89 nM and reduced the MIC of cefotaxime by 64-fold in CTX-M-9 expressing Escherichia coli. The in vitro potency gains were accompanied by improvements in ligand efficiency (from 0.30 to 0.39) and LipE (from 1.37 to 3.86). These new analogues represent the first nM-affinity noncovalent inhibitors of a class A {beta}-lactamase. Their complex crystal structures provide valuable information about ligand binding for future inhibitor design.

  15. A chimeric path to neuronal synchronization (United States)

    Essaki Arumugam, Easwara Moorthy; Spano, Mark L.


    Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an "all or none" phenomenon, but can pass through an intermediate stage (chimera).

  16. A chimeric path to neuronal synchronization

    Energy Technology Data Exchange (ETDEWEB)

    Essaki Arumugam, Easwara Moorthy; Spano, Mark L. [School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287-9709 (United States)


    Synchronization of neuronal activity is associated with neurological disorders such as epilepsy. This process of neuronal synchronization is not fully understood. To further our understanding, we have experimentally studied the progression of this synchronization from normal neuronal firing to full synchronization. We implemented nine FitzHugh-Nagumo neurons (a simplified Hodgkin-Huxley model) via discrete electronics. For different coupling parameters (synaptic strengths), the neurons in the ring were either unsynchronized or completely synchronized when locally coupled in a ring. When a single long-range connection (nonlocal coupling) was introduced, an intermediate state known as a chimera appeared. The results indicate that (1) epilepsy is likely not only a dynamical disease but also a topological disease, strongly tied to the connectivity of the underlying network of neurons, and (2) the synchronization process in epilepsy may not be an “all or none” phenomenon, but can pass through an intermediate stage (chimera)

  17. Linking neuronal ensembles by associative synaptic plasticity.

    Directory of Open Access Journals (Sweden)

    Qi Yuan

    Full Text Available Synchronized activity in ensembles of neurons recruited by excitatory afferents is thought to contribute to the coding information in the brain. However, the mechanisms by which neuronal ensembles are generated and modified are not known. Here we show that in rat hippocampal slices associative synaptic plasticity enables ensembles of neurons to change by incorporating neurons belonging to different ensembles. Associative synaptic plasticity redistributes the composition of different ensembles recruited by distinct inputs such as to specifically increase the similarity between the ensembles. These results show that in the hippocampus, the ensemble of neurons recruited by a given afferent projection is fluid and can be rapidly and persistently modified to specifically include neurons from different ensembles. This linking of ensembles may contribute to the formation of associative memories.

  18. Neuronal migration mechanisms in development and disease. (United States)

    Valiente, Manuel; Marín, Oscar


    Neuronal migration is a fundamental process that determines the final allocation of neurons in the nervous system, establishing the basis for the subsequent wiring of neural circuitry. From cell polarization to target identification, neuronal migration integrates multiple cellular and molecular events that enable neuronal precursors to move across the brain to reach their final destination. In this review we summarize novel findings on the key processes that govern the cell biology of migrating neurons, describing recent advances in their molecular regulation in different migratory pathways of the brain, spinal cord, and peripheral nervous system. We will also review how this basic knowledge is contributing to a better understanding of the etiology and pathophysiology of multiple neurological syndromes in which neuronal migration is disrupted.

  19. Nasal neuron PET imaging quantifies neuron generation and degeneration (United States)

    Van de Bittner, Genevieve C.; Riley, Misha M.; Cao, Luxiang; Herrick, Scott P.; Ricq, Emily L.; O’Neill, Michael J.; Ahmed, Zeshan; Murray, Tracey K.; Smith, Jaclyn E.; Wang, Changning; Schroeder, Frederick A.; Albers, Mark W.; Hooker, Jacob M.


    Olfactory dysfunction is broadly associated with neurodevelopmental and neurodegenerative diseases and predicts increased mortality rates in healthy individuals. Conventional measurements of olfactory health assess odor processing pathways within the brain and provide a limited understanding of primary odor detection. Quantification of the olfactory sensory neurons (OSNs), which detect odors within the nasal cavity, would provide insight into the etiology of olfactory dysfunction associated with disease and mortality. Notably, OSNs are continually replenished by adult neurogenesis in mammals, including humans, so OSN measurements are primed to provide specialized insights into neurological disease. Here, we have evaluated a PET radiotracer, [11C]GV1-57, that specifically binds mature OSNs and quantifies the mature OSN population in vivo. [11C]GV1-57 monitored native OSN population dynamics in rodents, detecting OSN generation during postnatal development and aging-associated neurodegeneration. [11C]GV1-57 additionally measured rates of neuron regeneration after acute injury and early-stage OSN deficits in a rodent tauopathy model of neurodegenerative disease. Preliminary assessment in nonhuman primates suggested maintained uptake and saturable binding of [18F]GV1-57 in primate nasal epithelium, supporting its translational potential. Future applications for GV1-57 include monitoring additional diseases or conditions associated with olfactory dysregulation, including cognitive decline, as well as monitoring effects of neuroregenerative or neuroprotective therapeutics. PMID:28112682

  20. Neuronal Networks on Nanocellulose Scaffolds. (United States)

    Jonsson, Malin; Brackmann, Christian; Puchades, Maja; Brattås, Karoline; Ewing, Andrew; Gatenholm, Paul; Enejder, Annika


    Proliferation, integration, and neurite extension of PC12 cells, a widely used culture model for cholinergic neurons, were studied in nanocellulose scaffolds biosynthesized by Gluconacetobacter xylinus to allow a three-dimensional (3D) extension of neurites better mimicking neuronal networks in tissue. The interaction with control scaffolds was compared with cationized nanocellulose (trimethyl ammonium betahydroxy propyl [TMAHP] cellulose) to investigate the impact of surface charges on the cell interaction mechanisms. Furthermore, coatings with extracellular matrix proteins (collagen, fibronectin, and laminin) were investigated to determine the importance of integrin-mediated cell attachment. Cell proliferation was evaluated by a cellular proliferation assay, while cell integration and neurite propagation were studied by simultaneous label-free Coherent anti-Stokes Raman Scattering and second harmonic generation microscopy, providing 3D images of PC12 cells and arrangement of nanocellulose fibrils, respectively. Cell attachment and proliferation were enhanced by TMAHP modification, but not by protein coating. Protein coating instead promoted active interaction between the cells and the scaffold, hence lateral cell migration and integration. Irrespective of surface modification, deepest cell integration measured was one to two cell layers, whereas neurites have a capacity to integrate deeper than the cell bodies in the scaffold due to their fine dimensions and amoeba-like migration pattern. Neurites with lengths of >50 μm were observed, successfully connecting individual cells and cell clusters. In conclusion, TMAHP-modified nanocellulose scaffolds promote initial cellular scaffold adhesion, which combined with additional cell-scaffold treatments enables further formation of 3D neuronal networks.

  1. Performance limitations of relay neurons.

    Directory of Open Access Journals (Sweden)

    Rahul Agarwal

    Full Text Available Relay cells are prevalent throughout sensory systems and receive two types of inputs: driving and modulating. The driving input contains receptive field properties that must be transmitted while the modulating input alters the specifics of transmission. For example, the visual thalamus contains relay neurons that receive driving inputs from the retina that encode a visual image, and modulating inputs from reticular activating system and layer 6 of visual cortex that control what aspects of the image will be relayed back to visual cortex for perception. What gets relayed depends on several factors such as attentional demands and a subject's goals. In this paper, we analyze a biophysical based model of a relay cell and use systems theoretic tools to construct analytic bounds on how well the cell transmits a driving input as a function of the neuron's electrophysiological properties, the modulating input, and the driving signal parameters. We assume that the modulating input belongs to a class of sinusoidal signals and that the driving input is an irregular train of pulses with inter-pulse intervals obeying an exponential distribution. Our analysis applies to any [Formula: see text] order model as long as the neuron does not spike without a driving input pulse and exhibits a refractory period. Our bounds on relay reliability contain performance obtained through simulation of a second and third order model, and suggest, for instance, that if the frequency of the modulating input increases or the DC offset decreases, then relay increases. Our analysis also shows, for the first time, how the biophysical properties of the neuron (e.g. ion channel dynamics define the oscillatory patterns needed in the modulating input for appropriately timed relay of sensory information. In our discussion, we describe how our bounds predict experimentally observed neural activity in the basal ganglia in (i health, (ii in Parkinson's disease (PD, and (iii in PD during

  2. Ion channels in neuronal survival

    Institute of Scientific and Technical Information of China (English)


    The study of ion channels represents one of the most active fields in neuroscience research in China.In the last 10 years,active research in various Chinese neuroscience institutions has sought to understand the mechanisms responsible for sensory processing,neural development and neurogenesis,neural plasticity,as well as pathogenesis.In addition,extensive studies have been directed to measure ion channel activity,structure-function relationships,as well as many other biophysical and biochemical properties.This review focuses on the progress achieved in the investigation of ion channels in neuronal survival during the past 10 years in China.

  3. Interleukin-1 and neuronal injury. (United States)

    Allan, Stuart M; Tyrrell, Pippa J; Rothwell, Nancy J


    Interleukin-1 is a pro-inflammatory cytokine that has numerous biological effects, including activation of many inflammatory processes (through activation of T cells, for example), induction of expression of acute-phase proteins, an important function in neuroimmune responses and direct effects on the brain itself. There is now extensive evidence to support the direct involvement of interleukin-1 in the neuronal injury that occurs in both acute and chronic neurodegenerative disorders. This article discusses the key evidence of a role for interleukin-1 in acute neurodegeneration - for example, stroke and brain trauma - and provides a rationale for targeting the interleukin-1 system as a therapeutic strategy.

  4. Mechanisms of Neuronal Apoptosis In Vivo (United States)


    Mechanisms for neuronal degeneration in amyotrophic rons in aging and neurological research: aluminum neu- lateral sclerosis and in models of motor neuron...not ture-DNA damage-lschemic neuronal death-MEKKI. Understanding the molecular regulation of apoptosis is such as Alzheimer disease (Anderson et al...WH, Jung Y-K, Kovacs DM and Tanzi RE: Kaneko K, Shimizu T, lihara K, Kojima T, Miyatake T and Alternative cleavage of Alzheimer -associated presenilins

  5. The genealogy of genealogy of neurons


    Moroz, Leonid L.


    Two scenarios of neuronal evolution (monophyly and polyphyly) are discussed in the historical timeline starting from the 19th century. The recent genomic studies on Ctenophores re-initiated a broad interest in the hypotheses of independent origins of neurons. However, even earlier work on ctenophores suggested that their nervous systems are unique in many aspects of their organization and a possibility of the independent origin of neurons and synapses was introduced well before modern advance...

  6. High-Degree Neurons Feed Cortical Computations.

    Directory of Open Access Journals (Sweden)

    Nicholas M Timme


    Full Text Available Recent work has shown that functional connectivity among cortical neurons is highly varied, with a small percentage of neurons having many more connections than others. Also, recent theoretical developments now make it possible to quantify how neurons modify information from the connections they receive. Therefore, it is now possible to investigate how information modification, or computation, depends on the number of connections a neuron receives (in-degree or sends out (out-degree. To do this, we recorded the simultaneous spiking activity of hundreds of neurons in cortico-hippocampal slice cultures using a high-density 512-electrode array. This preparation and recording method combination produced large numbers of neurons recorded at temporal and spatial resolutions that are not currently available in any in vivo recording system. We utilized transfer entropy (a well-established method for detecting linear and nonlinear interactions in time series and the partial information decomposition (a powerful, recently developed tool for dissecting multivariate information processing into distinct parts to quantify computation between neurons where information flows converged. We found that computations did not occur equally in all neurons throughout the networks. Surprisingly, neurons that computed large amounts of information tended to receive connections from high out-degree neurons. However, the in-degree of a neuron was not related to the amount of information it computed. To gain insight into these findings, we developed a simple feedforward network model. We found that a degree-modified Hebbian wiring rule best reproduced the pattern of computation and degree correlation results seen in the real data. Interestingly, this rule also maximized signal propagation in the presence of network-wide correlations, suggesting a mechanism by which cortex could deal with common random background input. These are the first results to show that the extent to

  7. A New Population of Parvocellular Oxytocin Neurons Controlling Magnocellular Neuron Activity and Inflammatory Pain Processing. (United States)

    Eliava, Marina; Melchior, Meggane; Knobloch-Bollmann, H Sophie; Wahis, Jérôme; da Silva Gouveia, Miriam; Tang, Yan; Ciobanu, Alexandru Cristian; Triana del Rio, Rodrigo; Roth, Lena C; Althammer, Ferdinand; Chavant, Virginie; Goumon, Yannick; Gruber, Tim; Petit-Demoulière, Nathalie; Busnelli, Marta; Chini, Bice; Tan, Linette L; Mitre, Mariela; Froemke, Robert C; Chao, Moses V; Giese, Günter; Sprengel, Rolf; Kuner, Rohini; Poisbeau, Pierrick; Seeburg, Peter H; Stoop, Ron; Charlet, Alexandre; Grinevich, Valery


    Oxytocin (OT) is a neuropeptide elaborated by the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei. Magnocellular OT neurons of these nuclei innervate numerous forebrain regions and release OT into the blood from the posterior pituitary. The PVN also harbors parvocellular OT cells that project to the brainstem and spinal cord, but their function has not been directly assessed. Here, we identified a subset of approximately 30 parvocellular OT neurons, with collateral projections onto magnocellular OT neurons and neurons of deep layers of the spinal cord. Evoked OT release from these OT neurons suppresses nociception and promotes analgesia in an animal model of inflammatory pain. Our findings identify a new population of OT neurons that modulates nociception in a two tier process: (1) directly by release of OT from axons onto sensory spinal cord neurons and inhibiting their activity and (2) indirectly by stimulating OT release from SON neurons into the periphery.

  8. Correction: Understanding metal homeostasis in primary cultured neurons. Studies using single neuron subcellular and quantitative metallomics. (United States)

    Colvin, Robert A; Lai, Barry; Holmes, William R; Lee, Daewoo


    Correction for 'Understanding metal homeostasis in primary cultured neurons. Studies using single neuron subcellular and quantitative metallomics' by Robert A. Colvin et al., Metallomics, 2015, 7, 1111-1123.

  9. Autosomal dominant adult neuronal ceroid lipofuscinosis

    NARCIS (Netherlands)

    Nijssen, Peter C.G.


    this thesis investigates a family with autosomal dominant neuronal ceroid lipofuscinosis, with chapters on clinical neurology, neuropathology, neurogenetics, neurophysiology, auditory and visual aspects.

  10. Shaping Neuronal Network Activity by Presynaptic Mechanisms.

    Directory of Open Access Journals (Sweden)

    Ayal Lavi


    Full Text Available Neuronal microcircuits generate oscillatory activity, which has been linked to basic functions such as sleep, learning and sensorimotor gating. Although synaptic release processes are well known for their ability to shape the interaction between neurons in microcircuits, most computational models do not simulate the synaptic transmission process directly and hence cannot explain how changes in synaptic parameters alter neuronal network activity. In this paper, we present a novel neuronal network model that incorporates presynaptic release mechanisms, such as vesicle pool dynamics and calcium-dependent release probability, to model the spontaneous activity of neuronal networks. The model, which is based on modified leaky integrate-and-fire neurons, generates spontaneous network activity patterns, which are similar to experimental data and robust under changes in the model's primary gain parameters such as excitatory postsynaptic potential and connectivity ratio. Furthermore, it reliably recreates experimental findings and provides mechanistic explanations for data obtained from microelectrode array recordings, such as network burst termination and the effects of pharmacological and genetic manipulations. The model demonstrates how elevated asynchronous release, but not spontaneous release, synchronizes neuronal network activity and reveals that asynchronous release enhances utilization of the recycling vesicle pool to induce the network effect. The model further predicts a positive correlation between vesicle priming at the single-neuron level and burst frequency at the network level; this prediction is supported by experimental findings. Thus, the model is utilized to reveal how synaptic release processes at the neuronal level govern activity patterns and synchronization at the network level.

  11. Effective stimuli for constructing reliable neuron models.

    Directory of Open Access Journals (Sweden)

    Shaul Druckmann


    Full Text Available The rich dynamical nature of neurons poses major conceptual and technical challenges for unraveling their nonlinear membrane properties. Traditionally, various current waveforms have been injected at the soma to probe neuron dynamics, but the rationale for selecting specific stimuli has never been rigorously justified. The present experimental and theoretical study proposes a novel framework, inspired by learning theory, for objectively selecting the stimuli that best unravel the neuron's dynamics. The efficacy of stimuli is assessed in terms of their ability to constrain the parameter space of biophysically detailed conductance-based models that faithfully replicate the neuron's dynamics as attested by their ability to generalize well to the neuron's response to novel experimental stimuli. We used this framework to evaluate a variety of stimuli in different types of cortical neurons, ages and animals. Despite their simplicity, a set of stimuli consisting of step and ramp current pulses outperforms synaptic-like noisy stimuli in revealing the dynamics of these neurons. The general framework that we propose paves a new way for defining, evaluating and standardizing effective electrical probing of neurons and will thus lay the foundation for a much deeper understanding of the electrical nature of these highly sophisticated and non-linear devices and of the neuronal networks that they compose.

  12. Spiking Neurons for Analysis of Patterns (United States)

    Huntsberger, Terrance


    Artificial neural networks comprising spiking neurons of a novel type have been conceived as improved pattern-analysis and pattern-recognition computational systems. These neurons are represented by a mathematical model denoted the state-variable model (SVM), which among other things, exploits a computational parallelism inherent in spiking-neuron geometry. Networks of SVM neurons offer advantages of speed and computational efficiency, relative to traditional artificial neural networks. The SVM also overcomes some of the limitations of prior spiking-neuron models. There are numerous potential pattern-recognition, tracking, and data-reduction (data preprocessing) applications for these SVM neural networks on Earth and in exploration of remote planets. Spiking neurons imitate biological neurons more closely than do the neurons of traditional artificial neural networks. A spiking neuron includes a central cell body (soma) surrounded by a tree-like interconnection network (dendrites). Spiking neurons are so named because they generate trains of output pulses (spikes) in response to inputs received from sensors or from other neurons. They gain their speed advantage over traditional neural networks by using the timing of individual spikes for computation, whereas traditional artificial neurons use averages of activity levels over time. Moreover, spiking neurons use the delays inherent in dendritic processing in order to efficiently encode the information content of incoming signals. Because traditional artificial neurons fail to capture this encoding, they have less processing capability, and so it is necessary to use more gates when implementing traditional artificial neurons in electronic circuitry. Such higher-order functions as dynamic tasking are effected by use of pools (collections) of spiking neurons interconnected by spike-transmitting fibers. The SVM includes adaptive thresholds and submodels of transport of ions (in imitation of such transport in biological

  13. Neuronal Classification of Atria Fibrillation

    Directory of Open Access Journals (Sweden)

    Mohamed BEN MESSAOUD


    Full Text Available Motivation. In medical field, particularly the cardiology, the diagnosis systems constitute the essential domain of research. In some applications, the traditional methods of classification present some limitations. The neuronal technique is considered as one of the promising algorithms to resolve such problem.Method. In this paper, two approaches of the Artificial Neuronal Network (ANN technique are investigated to classify the heart beats which are Multi Layer Perception (MLP and Radial Basis Function (RBF. A calculation algorithm of the RBF centers is proposed. For the Atria Fibrillation anomalies, an artificial neural network was used as a pattern classifier to distinguish three classes of the cardiac arrhythmias. The different classes consist of the normal beats (N, the Arrhythmia (AFA and Tachycardia (TFA Atria Fibrillation cases. The global and the partition classifier are performed. The arrhythmias of MIT-BIH database are analyzed. The ANN inputs are the temporal and morphological parameters deduced from the electrocardiograph.Results. The simulation results illustrate the performances of the studied versions of the neural network and give the fault detection rate of the tested data, a rate of classification reaching the 3.7%.Conclusion. This system can constitute a mesh in a chain of automated diagnosis and can be a tool for assistance for the classification of the cardiac anomalies in the services of urgencies before the arrival of a qualified personal person.

  14. Advances in motor neurone disease. (United States)

    Bäumer, Dirk; Talbot, Kevin; Turner, Martin R


    Motor neurone disease (MND), the commonest clinical presentation of which is amyotrophic lateral sclerosis (ALS), is regarded as the most devastating of adult-onset neurodegenerative disorders. The last decade has seen major improvements in patient care, but also rapid scientific advances, so that rational therapies based on key pathogenic mechanisms now seem plausible. ALS is strikingly heterogeneous in both its presentation, with an average one-year delay from first symptoms to diagnosis, and subsequent rate of clinical progression. Although half of patients succumb within 3-4 years of symptom onset, typically through respiratory failure, a significant minority survives into a second decade. Although an apparently sporadic disorder for most patients, without clear environmental triggers, recent genetic studies have identified disease-causing mutations in genes in several seemingly disparate functional pathways, so that motor neuron degeneration may need to be understood as a common final pathway with a number of upstream causes. This apparent aetiological and clinical heterogeneity suggests that therapeutic studies should include detailed biomarker profiling, and consider genetic as well as clinical stratification. The most common mutation, accounting for 10% of all Western hemisphere ALS, is a hexanucleotide repeat expansion in C9orf72. This and several other genes implicate altered RNA processing and protein degradation pathways in the core of ALS pathogenesis. A major gap remains in understanding how such fundamental processes appear to function without obvious deficit in the decades prior to symptom emergence, and the study of pre-symptomatic gene carriers is an important new initiative.

  15. BigNeuron: Large-Scale 3D Neuron Reconstruction from Optical Microscopy Images. (United States)

    Peng, Hanchuan; Hawrylycz, Michael; Roskams, Jane; Hill, Sean; Spruston, Nelson; Meijering, Erik; Ascoli, Giorgio A


    Understanding the structure of single neurons is critical for understanding how they function within neural circuits. BigNeuron is a new community effort that combines modern bioimaging informatics, recent leaps in labeling and microscopy, and the widely recognized need for openness and standardization to provide a community resource for automated reconstruction of dendritic and axonal morphology of single neurons.

  16. Essential roles of mitochondrial depolarization in neuron loss through microglial activation and attraction toward neurons. (United States)

    Nam, Min-Kyung; Shin, Hyun-Ah; Han, Ji-Hye; Park, Dae-Wook; Rhim, Hyangshuk


    As life spans increased, neurodegenerative disorders that affect aging populations have also increased. Progressive neuronal loss in specific brain regions is the most common cause of neurodegenerative disease; however, key determinants mediating neuron loss are not fully understood. Using a model of mitochondrial membrane potential (ΔΨm) loss, we found only 25% cell loss in SH-SY5Y (SH) neuronal mono-cultures, but interestingly, 85% neuronal loss occurred when neurons were co-cultured with BV2 microglia. SH neurons overexpressing uncoupling protein 2 exhibited an increase in neuron-microglia interactions, which represent an early step in microglial phagocytosis of neurons. This result indicates that ΔΨm loss in SH neurons is an important contributor to recruitment of BV2 microglia. Notably, we show that ΔΨm loss in BV2 microglia plays a crucial role in microglial activation and phagocytosis of damaged SH neurons. Thus, our study demonstrates that ΔΨm loss in both neurons and microglia is a critical determinant of neuron loss. These findings also offer new insights into neuroimmunological and bioenergetical aspects of neurodegenerative disease.

  17. Cerebellar Nuclear Neurons Use Time and Rate Coding to Transmit Purkinje Neuron Pauses. (United States)

    Sudhakar, Shyam Kumar; Torben-Nielsen, Benjamin; De Schutter, Erik


    Neurons of the cerebellar nuclei convey the final output of the cerebellum to their targets in various parts of the brain. Within the cerebellum their direct upstream connections originate from inhibitory Purkinje neurons. Purkinje neurons have a complex firing pattern of regular spikes interrupted by intermittent pauses of variable length. How can the cerebellar nucleus process this complex input pattern? In this modeling study, we investigate different forms of Purkinje neuron simple spike pause synchrony and its influence on candidate coding strategies in the cerebellar nuclei. That is, we investigate how different alignments of synchronous pauses in synthetic Purkinje neuron spike trains affect either time-locking or rate-changes in the downstream nuclei. We find that Purkinje neuron synchrony is mainly represented by changes in the firing rate of cerebellar nuclei neurons. Pause beginning synchronization produced a unique effect on nuclei neuron firing, while the effect of pause ending and pause overlapping synchronization could not be distinguished from each other. Pause beginning synchronization produced better time-locking of nuclear neurons for short length pauses. We also characterize the effect of pause length and spike jitter on the nuclear neuron firing. Additionally, we find that the rate of rebound responses in nuclear neurons after a synchronous pause is controlled by the firing rate of Purkinje neurons preceding it.

  18. NETMORPH: a framework for the stochastic generation of large scale neuronal networks with realistic neuron morphologies

    NARCIS (Netherlands)

    Koene, R.A.; Tijms, B.; van Hees, P.; Postma, F.; de Ridder, A.; Ramakers, G.J.A.; van Pelt, J.; van Ooyen, A.


    We present a simulation framework, called NETMORPH, for the developmental generation of 3D large-scale neuronal networks with realistic neuron morphologies. In NETMORPH, neuronal morphogenesis is simulated from the perspective of the individual growth cone. For each growth cone in a growing axonal o

  19. Neurons Are Recruited to a Memory Trace Based on Relative Neuronal Excitability Immediately before Training

    NARCIS (Netherlands)

    A.P. Yiu (Adelaide); V. Mercaldo (Valentina); C. Yan (Chen); B. Richards (Blake); M.U. Rashid (Muhammad); H.L. Hsiang (Hwa); J. Pressey (Jessica); V. Mahadevan (Vivek); M.M. Tran (Matthew); S.A. Kushner (Steven); M.A. Woodin (Melanie); P.W. Frankland (Paul); S.A. Josselyn (Sheena)


    textabstractMemories are thought to be sparsely encoded in neuronal networks, but little is known about why a given neuron is recruited or allocated to a particular memory trace. Previous research shows that in the lateral amygdala (LA), neurons with increased CREB are selectively recruited to a fea

  20. Human Motor Neuron Progenitor Transplantation Leads to Endogenous Neuronal Sparing in 3 Models of Motor Neuron Loss

    Directory of Open Access Journals (Sweden)

    Tanya J. Wyatt


    Full Text Available Motor neuron loss is characteristic of many neurodegenerative disorders and results in rapid loss of muscle control, paralysis, and eventual death in severe cases. In order to investigate the neurotrophic effects of a motor neuron lineage graft, we transplanted human embryonic stem cell-derived motor neuron progenitors (hMNPs and examined their histopathological effect in three animal models of motor neuron loss. Specifically, we transplanted hMNPs into rodent models of SMA (Δ7SMN, ALS (SOD1 G93A, and spinal cord injury (SCI. The transplanted cells survived and differentiated in all models. In addition, we have also found that hMNPs secrete physiologically active growth factors in vivo, including NGF and NT-3, which significantly enhanced the number of spared endogenous neurons in all three animal models. The ability to maintain dying motor neurons by delivering motor neuron-specific neurotrophic support represents a powerful treatment strategy for diseases characterized by motor neuron loss.

  1. Nitric oxide damages neuronal mitochondria and induces apoptosis in neurons

    Institute of Scientific and Technical Information of China (English)


    The cytotoxic effect of nitric oxide on primarily cultured rat cerebellar granule cells was studied,and the mechanisms were discussed.The results showed that nitric oxide donor S-nitroso-N-acetyl-penicillamine (SNAP; 500 μmol/L) could induce apoptosis in immature cultures of cerebellar granule cells.Flow cytometry and HPLC analyses revealed that after treatment with SNAP,the mitochondrial transmembrane potential and the cellular ATP content decreased significantly.Nitric oxide scavenger hemoglobin could effectively prevent the neuronal mitochondria from dysfunction and attenuate apoptosis.The results suggested that nitric oxide activated the apoptotic program by inhibiting the activity of mitochondrial respiratory chain and thus decreasing the cellular ATP content.

  2. PPAR{gamma} transcriptionally regulates the expression of insulin-degrading enzyme in primary neurons

    Energy Technology Data Exchange (ETDEWEB)

    Du, Jing; Zhang, Lang; Liu, Shubo; Zhang, Chi [Protein Science Key Laboratory of the Ministry of Education, Department of Biological Sciences and Biotechnology, School of Medicine, Tsinghua University, Beijing 100084 (China); Huang, Xiuqing; Li, Jian [The Key Laboratory of Geriatrics, Beijing Hospital and Beijing Institute of Geriatrics, Ministry of Health, Beijing 100730 (China); Zhao, Nanming [Protein Science Key Laboratory of the Ministry of Education, Department of Biological Sciences and Biotechnology, School of Medicine, Tsinghua University, Beijing 100084 (China); Wang, Zhao, E-mail: [Protein Science Key Laboratory of the Ministry of Education, Department of Biological Sciences and Biotechnology, School of Medicine, Tsinghua University, Beijing 100084 (China)


    Insulin-degrading enzyme (IDE) is a protease that has been demonstrated to play a key role in degrading both A{beta} and insulin and deficient in IDE function is associated with Alzheimer's disease (AD) and type 2 diabetes mellitus (DM2) pathology. However, little is known about the cellular and molecular regulation of IDE expression. Here we show IDE levels are markedly decreased in DM2 patients and positively correlated with the peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) levels. Further studies show that PPAR{gamma} plays an important role in regulating IDE expression in rat primary neurons through binding to a functional peroxisome proliferator-response element (PPRE) in IDE promoter and promoting IDE gene transcription. Finally, we demonstrate that PPAR{gamma} participates in the insulin-induced IDE expression in neurons. These results suggest that PPAR{gamma} transcriptionally induces IDE expression which provides a novel mechanism for the use of PPAR{gamma} agonists in both DM2 and AD therapies.

  3. A beta-l-Arabinopyranosidase from Streptomyces avermitilis is a novel member of glycoside hydrolase family 27. (United States)

    Ichinose, Hitomi; Fujimoto, Zui; Honda, Mariko; Harazono, Koichi; Nishimoto, Yukifumi; Uzura, Atsuko; Kaneko, Satoshi


    Arabinogalactan proteins (AGPs) are a family of plant cell surface proteoglycans and are considered to be involved in plant growth and development. Because AGPs are very complex molecules, glycoside hydrolases capable of degrading AGPs are powerful tools for analyses of the AGPs. We previously reported such enzymes from Streptomyces avermitilis. Recently, a beta-l-arabinopyranosidase was purified from the culture supernatant of the bacterium, and its corresponding gene was identified. The primary structure of the protein revealed that the catalytic module was highly similar to that of glycoside hydrolase family 27 (GH27) alpha-d-galactosidases. The recombinant protein was successfully expressed as a secreted 64-kDa protein using a Streptomyces expression system. The specific activity toward p-nitrophenyl-beta-l-arabinopyranoside was 18 micromol of arabinose/min/mg, which was 67 times higher than that toward p- nitrophenyl-alpha-d-galactopyranoside. The enzyme could remove 0.1 and 45% l-arabinose from gum arabic or larch arabinogalactan, respectively. X-ray crystallographic analysis reveals that the protein had a GH27 catalytic domain, an antiparallel beta-domain containing Greek key motifs, another antiparallel beta-domain forming a jellyroll structure, and a carbohydrate-binding module family 13 domain. Comparison of the structure of this protein with that of alpha-d-galactosidase showed a single amino acid substitution (aspartic acid to glutamic acid) in the catalytic pocket of beta-l-arabinopyranosidase, and a space for the hydroxymethyl group on the C-5 carbon of d-galactose bound to alpha-galactosidase was changed in beta-l-arabinopyranosidase. Mutagenesis study revealed that the residue is critical for modulating the enzyme activity. This is the first report in which beta-l-arabinopyranosidase is classified as a new member of the GH27 family.

  4. Effect of GDNF against kainic acid excitotoxicity on cultured neonatal rats doral root ganlian neurons%胶质源性神经营养因子对损伤的培养大鼠背根神经节的作用

    Institute of Scientific and Technical Information of China (English)

    毕辉; 杨浩; 杜亮; 胡三觉


    目的 应用体外培养海人藻酸(KA)兴奋性毒素损伤的细胞模型,研究GDNF对损伤的背根节神经元的不同作用,为进一步研究GDNF对神经元作用机制,表达产生及检测方法提供思路.方法 采用原代培养的方法,用N1无血清分离培养背根节神经元,再用5μmol.L-1KA作用6~8h,加上含有GDNF的无血清培养基,继续培养24h,然后用MTT法检测反映细胞的活性,胎盘蓝染色记数、细胞总蛋白测定以及形态学观察突起的生长状况.结果 ①细胞活性A值:GDNF+KA(0.0328±0.006),KA(0.0285±0.0075),GDNF(0.0398±0.002),Blank(0.041±0.002)(P<0.05);②活细胞数相应为GDNF+KA(60±4.4),KA(35.7±2.2),GDNF(59.3±3.6),Blank(57.7±2.9);③细胞的总蛋白分别为GDNF+KA(70.3±9.2)(P<0.01),KA(49.0±3.7),GDNF(75.0±7.3),Blank(68.0±5.5)(P<0.01);④突起长度:实验组与对照组不明显,GDNF组与空白对照组不明显.结论 在正常无血清体外培养情况下GDNF对DRG神经元作用不明显,在KA兴奋性毒素损伤后,对细胞的活性、存活及总蛋白合成有明显的保护作用,但对突起的生长则没有明显的促进作用.%AIM To study the different effects of glial-de-rived neurotrophicfactor( GDNF) on injured dosal root ganglion(DRG) neurons using injurious model of neurons induced by kainic acid in vitro, so as to provide new thoughts for studying functional mechanism, expression pattern, and bioassay methods of GDNF. METHODS Primarily cultured DRG neurons were dissected from neonatal rats in N1 serum-free medium,and then kainic acid medium was added into cultures at the final concentration of 5 μmol.L-1 and incubated for 6~8 h . The next step was performed to culture in DF12 serum-free medium supplemented with GDNF for 24 h. Eventually, MTT was used to test viability of cells by value. Trypan blue staining cell count and total protein of neurons were determined. DRG neurons were observed to detect the

  5. 实验性结肠炎对脊髓传入神经元中降钙素基因相关肽和香草酸受体1表达的调节%Effects of experimental colitis on the expressions of calcitonin gene-related peptide and vanilloid receptor 1 in rat spinal cord sensory neurons

    Institute of Scientific and Technical Information of China (English)

    杨霞; 韩俊庆; 刘然


    本文旨在探讨肠道局部炎症对脊髓肠道感觉传入神经通路的近期及远期效应,应用三硝基苯磺酸(trinitrobenzenesulfonic acid,TNBS)建立大鼠结肠炎动物模型,用DiI(3)逆行神经标记法识别支配肠道炎症部位的脊髓背根神经节(dorsalrootganglia,DRG)神经元,通过肉眼观察、平均组织损伤评分及髓过氧化物酶活性测定等方法评价肠道组织的炎症反应状态,用免疫组织化学法测定香草酸受体l(vanilloid receptor 1,VRl)和降钙素基因相关肽(calcitonin gene-related peptide,CGRP)在支配结肠炎症部位的DRG神经元中的表达,比较炎症不同阶段(给予TNBS后7、21、42 d)CGRP和VRI阳性神经元的数目.结果显示,炎症急性期(即给予TNBS后7 d)结肠黏膜肉眼可见明显损伤,同时相应DRG中表达CGRP及VRl的神经元增加近2倍[(95.38±9.45)%VS(42.86±5.02)%,(89.23±8.21)%VS(32.54±4.58)%].给予TNBS后21、42 d,肠道炎症反应已完全消退,但表达CGRP及VRl的DRG神经元数目仍明显高于对照组[(86.25±8.21)%,(68.28±7.12)%VS(42.86±5.02)%;(67.22±6.52)%,(56.25±4.86)%VS(32.54±4.58)%].结果提示,肠道局部炎症可以上调支配肠道的脊髓传入神经元中CGRP和VRl的表达,这种异常表达可以持续至肠道炎症反应消退后的一定时间.%To study the acute and long-term effects of local gut infammation on the sensitivity of the spinal sensory neurons,the expressions of vanilloid receptor 1(VR1)and calcitonin gene-related peptide(CGRP)in the colon-innervated primary sensory neurons in dorsal root ganglia(DRG)were examined in rats with trinitrobenzenesulfonic acid(TNBS)-induced experimental colitis.The neurons projecting to the distal colon were identified by DiI(3)retrograde labelling.Macroscopic examination,mean damage score and myeloperoxidase(MPO)activity were determined to assess the inflammatory status of the colon tissue.The number of CGRP and VR1 immunoreactive neurons at different stages of

  6. Enoxaparin treatment administered at both early and late stages of amyloid beta deposition improves cognition of APPswe/PS1dE9 mice with differential effects on brain A beta levels.

    NARCIS (Netherlands)

    Timmer, N.M.; Dijk, L. van; Zee, C.E.E.M. van der; Kiliaan, A.J.; Waal, R.M.W. de; Verbeek, M.M.


    Enoxaparin (Enox), a low molecular weight heparin, has been shown to lower brain amyloid beta (A beta) load in a mouse model for Alzheimer's disease. However, the effect of Enox on cognition was not studied. Therefore, we examined the effect of peripheral Enox treatment on cognition and brain A beta

  7. Local and commissural IC neurons make axosomatic inputs on large GABAergic tectothalamic neurons. (United States)

    Ito, Tetsufumi; Oliver, Douglas L


    Large GABAergic (LG) neurons are a distinct type of neuron in the inferior colliculus (IC) identified by their dense vesicular glutamate transporter 2 (VGLUT2)-containing axosomatic synaptic terminals. Yet the sources of these terminals are unknown. Since IC glutamatergic neurons express VGLUT2, and IC neurons are known to have local collaterals, we tested the hypothesis that these excitatory, glutamatergic axosomatic inputs on LG neurons come from local axonal collaterals and commissural IC neurons. We injected a recombinant viral tracer into the IC which enabled Golgi-like green fluorescent protein (GFP) labeling in both dendrites and axons. In all cases, we found terminals positive for both GFP and VGLUT2 (GFP+/VGLUT2+) that made axosomatic contacts on LG neurons. One to six axosomatic contacts were made on a single LG cell body by a single axonal branch. The GFP-labeled neurons giving rise to the VGLUT2+ terminals on LG neurons were close by. The density of GFP+/VGLUT2+ terminals on the LG neurons was related to the number of nearby GFP-labeled cells. On the contralateral side, a smaller number of LG neurons received axosomatic contacts from GFP+/VGLUT2+ terminals. In cases with a single GFP-labeled glutamatergic neuron, the labeled axonal plexus was flat, oriented in parallel to the fibrodendritic laminae, and contacted 9-30 LG cell bodies within the plexus. Our data demonstrated that within the IC microcircuitry there is a convergence of inputs from local IC excitatory neurons on LG cell bodies. This suggests that LG neurons are heavily influenced by the activity of the nearby laminar glutamatergic neurons in the IC.

  8. Uncertainty propagation in neuronal dynamical systems

    NARCIS (Netherlands)

    Torres Valderrama, A.; Blom, J.G.


    One of the most notorious characteristics of neuronal electrical activity is its variability, whose origin is not just instrumentation noise, but mainly the intrinsically stochastic nature of neural computations. Neuronal models based on deterministic differential equations cannot account for such v

  9. SnapShot: Neuronal Regulation of Aging. (United States)

    Weir, Heather J; Mair, William B


    Aging is characterized by loss of homeostasis across multiple tissues. The nervous system governs whole-body homeostasis by communicating external and internal signals to peripheral tissues. Here, we highlight neuronal mechanisms and downstream outputs that regulate aging and longevity. Targeting these neuronal pathways may be a novel strategy to promote healthy aging. To view this SnapShot, open or download the PDF.

  10. Polarity and intracellular compartmentalization of Drosophila neurons

    Directory of Open Access Journals (Sweden)

    Henner Astra L


    Full Text Available Abstract Background Proper neuronal function depends on forming three primary subcellular compartments: axons, dendrites, and soma. Each compartment has a specialized function (the axon to send information, dendrites to receive information, and the soma is where most cellular components are produced. In mammalian neurons, each primary compartment has distinctive molecular and morphological features, as well as smaller domains, such as the axon initial segment, that have more specialized functions. How neuronal subcellular compartments are established and maintained is not well understood. Genetic studies in Drosophila have provided insight into other areas of neurobiology, but it is not known whether flies are a good system in which to study neuronal polarity as a comprehensive analysis of Drosophila neuronal subcellular organization has not been performed. Results Here we use new and previously characterized markers to examine Drosophila neuronal compartments. We find that: axons and dendrites can accumulate different microtubule-binding proteins; protein synthesis machinery is concentrated in the cell body; pre- and post-synaptic sites localize to distinct regions of the neuron; and specializations similar to the initial segment are present. In addition, we track EB1-GFP dynamics and determine microtubules in axons and dendrites have opposite polarity. Conclusion We conclude that Drosophila will be a powerful system to study the establishment and maintenance of neuronal compartments.

  11. Social neuroscience: mirror neurons recorded in humans. (United States)

    Keysers, Christian; Gazzola, Valeria


    New single-cell recordings show that humans do have mirror neurons, and in more brain regions than previously suspected. Some action-execution neurons were seen to be inhibited during observation, possibly preventing imitation and helping self/other discrimination.

  12. Do mirror neurons subserve action understanding? (United States)

    Hickok, Gregory


    Mirror neurons were once widely believed to support action understanding via motor simulation of the observed actions. Recent evidence regarding the functional properties of mirror neurons in monkeys as well as much neuropsychological evidence in humans has shown that this is not the case.

  13. Where do mirror neurons come from? (United States)

    Heyes, Cecilia


    Debates about the evolution of the 'mirror neuron system' imply that it is an adaptation for action understanding. Alternatively, mirror neurons may be a byproduct of associative learning. Here I argue that the adaptation and associative hypotheses both offer plausible accounts of the origin of mirror neurons, but the associative hypothesis has three advantages. First, it provides a straightforward, testable explanation for the differences between monkeys and humans that have led some researchers to question the existence of a mirror neuron system. Second, it is consistent with emerging evidence that mirror neurons contribute to a range of social cognitive functions, but do not play a dominant, specialised role in action understanding. Finally, the associative hypothesis is supported by recent data showing that, even in adulthood, the mirror neuron system can be transformed by sensorimotor learning. The associative account implies that mirror neurons come from sensorimotor experience, and that much of this experience is obtained through interaction with others. Therefore, if the associative account is correct, the mirror neuron system is a product, as well as a process, of social interaction.

  14. Mirror neurons: functions, mechanisms and models. (United States)

    Oztop, Erhan; Kawato, Mitsuo; Arbib, Michael A


    Mirror neurons for manipulation fire both when the animal manipulates an object in a specific way and when it sees another animal (or the experimenter) perform an action that is more or less similar. Such neurons were originally found in macaque monkeys, in the ventral premotor cortex, area F5 and later also in the inferior parietal lobule. Recent neuroimaging data indicate that the adult human brain is endowed with a "mirror neuron system," putatively containing mirror neurons and other neurons, for matching the observation and execution of actions. Mirror neurons may serve action recognition in monkeys as well as humans, whereas their putative role in imitation and language may be realized in human but not in monkey. This article shows the important role of computational models in providing sufficient and causal explanations for the observed phenomena involving mirror systems and the learning processes which form them, and underlines the need for additional circuitry to lift up the monkey mirror neuron circuit to sustain the posited cognitive functions attributed to the human mirror neuron system.

  15. The Mirror Neuron System and Action Recognition (United States)

    Buccino, Giovanni; Binkofski, Ferdinand; Riggio, Lucia


    Mirror neurons, first described in the rostral part of monkey ventral premotor cortex (area F5), discharge both when the animal performs a goal-directed hand action and when it observes another individual performing the same or a similar action. More recently, in the same area mirror neurons responding to the observation of mouth actions have been…

  16. Neuronal hyperplasia in the anal canal

    DEFF Research Database (Denmark)

    Fenger, C; Schrøder, H D


    In a consecutive series of minor surgical specimens from the anal canal, neuronal hyperplasia was found in nine of 56 haemorrhoidectomy specimens and in four of 23 fibrous polyps. In an additional series of 14 resections of the anal canal, neuronal hyperplasia was present in six cases, of which...

  17. Neuronal 'On' and 'Off' signals control microglia

    NARCIS (Netherlands)

    Biber, Knut; Neumann, Harald; Inoue, Kazuhide; Boddeke, Hendrikus W. G. M.


    Recent findings indicate that neurons are not merely passive targets of microglia but rather control microglial activity. The variety of different signals that neurons use to control microglia can be divided into two categories: 'Off' signals constitutively keep microglia in their resting state and

  18. Adaptive Neurons For Artificial Neural Networks (United States)

    Tawel, Raoul


    Training time decreases dramatically. In improved mathematical model of neural-network processor, temperature of neurons (in addition to connection strengths, also called weights, of synapses) varied during supervised-learning phase of operation according to mathematical formalism and not heuristic rule. Evidence that biological neural networks also process information at neuronal level.

  19. Bursting and synaptic plasticity in neuronal networks

    NARCIS (Netherlands)

    Stegenga, Jan


    Networks of neonatal cortical neurons, cultured on multi electrode arrays (MEAs) exhibit spontaneous action potential firings. The electrodes embedded in the glass surface of a MEA can be used to record and stimulate activity at 60 sites in a network of ~50.000 neurons. Such in-vitro networks enable

  20. Neuronal synchrony does not represent texture segregation

    NARCIS (Netherlands)

    Lamme, V.A.F.; Spekreijse, H.


    The visual environment is perceived as an organized whole of objects and their surroundings. In many visual cortical areas, however, neurons are typically activated when a stimulus is presented over a very limited portion of the visual field, the receptive field of that neuron(1-4). To bridge the ga

  1. Kisspeptin Excitation of GnRH Neurons (United States)

    Rønnekleiv, Oline K.; Kelly, Martin J.


    Kisspeptin binding to its cognate G protein-coupled receptor (GPR54, aka Kiss1R) in gonadotropin-releasing hormone (GnRH) neurons stimulates peptide release and activation of the reproductive axis in mammals. Kisspeptin has pronounced pre- and postsynaptic effects, with the latter dominating the excitability of GnRH neurons. Presynaptically, kisspeptin increases the excitatory drive (both GABA-A and glutamate) to GnRH neurons and postsynaptically, kisspeptin inhibits an A-type and inwardly rectifying K + (Kir 6.2 and GIRK) currents and activates nonselective cation (TRPC) currents to cause long-lasting depolarization and increased action potential firing. The signaling cascades and the multiple intracellular targets of kisspeptin actions in native GnRH neurons are continuing to be elucidated. This review summarizes our current state of knowledge about kisspeptin signaling in GnRH neurons. PMID:23550004

  2. Attractor dynamics in local neuronal networks

    Directory of Open Access Journals (Sweden)

    Jean-Philippe eThivierge


    Full Text Available Patterns of synaptic connectivity in various regions of the brain are characterized by the presence of synaptic motifs, defined as unidirectional and bidirectional synaptic contacts that follow a particular configuration and link together small groups of neurons. Recent computational work proposes that a relay network (two populations communicating via a third, relay population of neurons can generate precise patterns of neural synchronization. Here, we employ two distinct models of neuronal dynamics and show that simulated neural circuits designed in this way are caught in a global attractor of activity that prevents neurons from modulating their response on the basis of incoming stimuli. To circumvent the emergence of a fixed global attractor, we propose a mechanism of selective gain inhibition that promotes flexible responses to external stimuli. We suggest that local neuronal circuits may employ this mechanism to generate precise patterns of neural synchronization whose transient nature delimits the occurrence of a brief stimulus.

  3. A hybrid bioorganic interface for neuronal photoactivation. (United States)

    Ghezzi, Diego; Antognazza, Maria Rosa; Dal Maschio, Marco; Lanzarini, Erica; Benfenati, Fabio; Lanzani, Guglielmo


    A key issue in the realization of retinal prosthetic devices is reliable transduction of information carried by light into specific patterns of electrical activity in visual information processing networks. Soft organic materials can be used to couple artificial sensors with neuronal tissues. Here, we interface a network of primary neurons with an organic blend. We show that primary neurons can be successfully grown onto the polymer layer without affecting the optoelectronic properties of the active material or the biological functionality of neuronal network. Moreover, action potentials can be triggered in a temporally reliable and spatially selective manner with short pulses of visible light. Our results may lead to new neuronal communication and photo manipulation techniques, thus paving way to the development of artificial retinas and other neuroprosthetic interfaces based on organic photodetectors.

  4. Mirror neurons: their implications for group psychotherapy. (United States)

    Schermer, Victor L


    Recently discovered mirror neurons in the motor cortex of the brain register the actions and intentions of both the organism and others in the environment. As such, they may play a significant role in social behavior and groups. This paper considers the potential implications of mirror neurons and related neural networks for group therapists, proposing that mirror neurons and mirror systems provide "hard-wired" support for the group therapist's belief in the centrality of relationships in the treatment process and exploring their value in accounting for group-as-a-whole phenomena. Mirror neurons further confirm the holistic, social nature of perception, action, and intention as distinct from a stimulus-response behaviorism. The implications of mirror neurons and mirroring processes for the group therapist role, interventions, and training are also discussed.

  5. Mirror neurons through the lens of epigenetics. (United States)

    Ferrari, Pier F; Tramacere, Antonella; Simpson, Elizabeth A; Iriki, Atsushi


    The consensus view in mirror neuron research is that mirror neurons comprise a uniform, stable execution-observation matching system. In this opinion article, we argue that, in light of recent evidence, this is at best an incomplete and oversimplified view of mirror neurons, where activity is actually variable and more plastic than previously theorized. We propose an epigenetic account for understanding developmental changes in sensorimotor systems, including variations in mirror neuron activity. Although associative and genetic accounts fail to consider the complexity of genetic and nongenetic interactions, we propose a new evolutionary developmental biology (evo-devo) perspective, which predicts that environmental differences early in development should produce variations in mirror neuron response patterns, tuning them to the social environment.

  6. Reflections on mirror neurons and speech perception. (United States)

    Lotto, Andrew J; Hickok, Gregory S; Holt, Lori L


    The discovery of mirror neurons, a class of neurons that respond when a monkey performs an action and also when the monkey observes others producing the same action, has promoted a renaissance for the Motor Theory (MT) of speech perception. This is because mirror neurons seem to accomplish the same kind of one to one mapping between perception and action that MT theorizes to be the basis of human speech communication. However, this seeming correspondence is superficial, and there are theoretical and empirical reasons to temper enthusiasm about the explanatory role mirror neurons might have for speech perception. In fact, rather than providing support for MT, mirror neurons are actually inconsistent with the central tenets of MT.

  7. A computational model of motor neuron degeneration. (United States)

    Le Masson, Gwendal; Przedborski, Serge; Abbott, L F


    To explore the link between bioenergetics and motor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP production and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeostasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fasciculation-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fasciculation, and differential vulnerability of motor neuron subpopulations.

  8. [Impact of opiates on dopaminergic neurons]. (United States)

    Kaufling, Jennifer; Freund-Mercier, Marie-José; Barrot, Michel


    Since the work of Johnson and North, it is known that opiates increase the activity of dopaminergic neurons by a GABA neuron-mediated desinhibition. This model should however be updated based on recent advances. Thus, the neuroanatomical location of the GABA neurons responsible for this desinhibition has been recently detailed: they belong to a brain structure in continuity with the posterior part of the ventral tegmental area and discovered this past decade. Other data also highlighted the critical role played by glutamatergic transmission in the opioid regulation of dopaminergic neuron activity. During protracted opiate withdrawal, the inhibitory/excitatory balance exerted on dopaminergic neurons is altered. These results are now leading to propose an original hypothesis for explaining the impact of protracted opiate withdrawal on mood.

  9. Targeting neurons and photons for optogenetics. (United States)

    Packer, Adam M; Roska, Botond; Häusser, Michael


    Optogenetic approaches promise to revolutionize neuroscience by using light to manipulate neural activity in genetically or functionally defined neurons with millisecond precision. Harnessing the full potential of optogenetic tools, however, requires light to be targeted to the right neurons at the right time. Here we discuss some barriers and potential solutions to this problem. We review methods for targeting the expression of light-activatable molecules to specific cell types, under genetic, viral or activity-dependent control. Next we explore new ways to target light to individual neurons to allow their precise activation and inactivation. These techniques provide a precision in the temporal and spatial activation of neurons that was not achievable in previous experiments. In combination with simultaneous recording and imaging techniques, these strategies will allow us to mimic the natural activity patterns of neurons in vivo, enabling previously impossible 'dream experiments'.

  10. Effects of surface asymmetry on neuronal growth (United States)

    Staii, Cristian

    Understanding the brain is of tremendous fundamental importance, but it is immensely challenging because of the complexity of both its architecture and function. A growing body of evidence shows that physical stimuli (stiffness of the growth substrate, gradients of various molecular species, geometry of the surrounding environment, traction forces etc.) play a key role in the wiring up of the nervous system. I will present a systematic experimental and theoretical investigation of neuronal growth on substrates with asymmetric geometries and textures. The experimental results show unidirectional axonal growth on these substrates. We demonstrate that the unidirectional bias is imparted by the surface ratchet geometry and quantify the geometrical guidance cues that control neuronal growth. Our results provide new insight into the role played by physical cues in neuronal growth, and could lead to new methods for stimulating neuronal regeneration and the engineering of artificial neuronal tissue. We acknowledge support from NSF through CBET 1067093.

  11. Quantitative Map of Proteome Dynamics during Neuronal Differentiation

    NARCIS (Netherlands)

    Frese, Christian K; Mikhaylova, Marina; Stucchi, Riccardo; Gautier, Violette; Liu, Qingyang; Mohammed, Shabaz; Heck, Albert J R; Altelaar, A F Maarten; Hoogenraad, Casper C


    Neuronal differentiation is a multistep process that shapes and re-shapes neurons by progressing through several typical stages, including axon outgrowth, dendritogenesis, and synapse formation. To systematically profile proteome dynamics throughout neuronal differentiation, we took cultured rat hip

  12. A single-neuron tracing study of arkypallidal and prototypic neurons in healthy rats. (United States)

    Fujiyama, Fumino; Nakano, Takashi; Matsuda, Wakoto; Furuta, Takahiro; Udagawa, Jun; Kaneko, Takeshi


    The external globus pallidus (GP) is known as a relay nucleus of the indirect pathway of the basal ganglia. Recent studies in dopamine-depleted and healthy rats indicate that the GP comprises two main types of pallidofugal neurons: the so-called "prototypic" and "arkypallidal" neurons. However, the reconstruction of complete arkypallidal neurons in healthy rats has not been reported. Here we visualized the entire axonal arborization of four single arkypallidal neurons and six single prototypic neurons in rat brain using labeling with a viral vector expressing membrane-targeted green fluorescent protein and examined the distribution of axon boutons in the target nuclei. Results revealed that not only the arkypallidal neurons but nearly all of the prototypic neurons projected to the striatum with numerous axon varicosities. Thus, the striatum is a major target nucleus for pallidal neurons. Arkypallidal and prototypic GP neurons located in the calbindin-positive and calbindin-negative regions mainly projected to the corresponding positive and negative regions in the striatum. Because the GP and striatum calbindin staining patterns reflect the topographic organization of the striatopallidal projection, the striatal neurons in the sensorimotor and associative regions constitute the reciprocal connection with the GP neurons in the corresponding regions.

  13. Neuron-derived IgG protects neurons from complement-dependent cytotoxicity. (United States)

    Zhang, Jie; Niu, Na; Li, Bingjie; McNutt, Michael A


    Passive immunity of the nervous system has traditionally been thought to be predominantly due to the blood-brain barrier. This concept must now be revisited based on the existence of neuron-derived IgG. The conventional concept is that IgG is produced solely by mature B lymphocytes, but it has now been found to be synthesized by murine and human neurons. However, the function of this endogenous IgG is poorly understood. In this study, we confirm IgG production by rat cortical neurons at the protein and mRNA levels, with 69.0 ± 5.8% of cortical neurons IgG-positive. Injury to primary-culture neurons was induced by complement leading to increases in IgG production. Blockage of neuron-derived IgG resulted in more neuronal death and early apoptosis in the presence of complement. In addition, FcγRI was found in microglia and astrocytes. Expression of FcγR I in microglia was increased by exposure to neuron-derived IgG. Release of NO from microglia triggered by complement was attenuated by neuron-derived IgG, and this attenuation could be reversed by IgG neutralization. These data demonstrate that neuron-derived IgG is protective of neurons against injury induced by complement and microglial activation. IgG appears to play an important role in maintaining the stability of the nervous system.

  14. Active properties of neuronal dendrites. (United States)

    Johnston, D; Magee, J C; Colbert, C M; Cristie, B R


    Dendrites of neurons in the central nervous system are the principal sites for excitatory synaptic input. Although little is known about their function, two disparate perspectives have arisen to describe the activity patterns inherent to these diverse tree-like structures. Dendrites are thus considered either passive or active in their role in integrating synaptic inputs. This review follows the history of dendritic research from before the turn of the century to the present, with a primary focus on the hippocampus. A number of recent techniques, including high-speed fluorescence imaging and dendritic patch clamping, have provided new information and perspectives about the active properties of dendrites. The results support previous notions about the dendritic propagation of action potentials and also indicate which types of voltage-gated sodium and calcium channels are expressed and functionally active in dendrites. Possible roles for the active properties of dendrites in synaptic plasticity and integration are also discussed.

  15. Parallel network simulations with NEURON. (United States)

    Migliore, M; Cannia, C; Lytton, W W; Markram, Henry; Hines, M L


    The NEURON simulation environment has been extended to support parallel network simulations. Each processor integrates the equations for its subnet over an interval equal to the minimum (interprocessor) presynaptic spike generation to postsynaptic spike delivery connection delay. The performance of three published network models with very different spike patterns exhibits superlinear speedup on Beowulf clusters and demonstrates that spike communication overhead is often less than the benefit of an increased fraction of the entire problem fitting into high speed cache. On the EPFL IBM Blue Gene, almost linear speedup was obtained up to 100 processors. Increasing one model from 500 to 40,000 realistic cells exhibited almost linear speedup on 2,000 processors, with an integration time of 9.8 seconds and communication time of 1.3 seconds. The potential for speed-ups of several orders of magnitude makes practical the running of large network simulations that could otherwise not be explored.

  16. Novel model of neuronal bioenergetics

    DEFF Research Database (Denmark)

    Bak, Lasse Kristoffer; Obel, Linea Lykke Frimodt; Walls, Anne B;


    -methyl-d-aspartate)-induced synaptic activity and that lactate alone is not able to support neurotransmitter glutamate homoeostasis. Subsequently, a model was proposed to explain these results at the cellular level. In brief, the intermittent rises in intracellular Ca2+ during activation cause influx of Ca2+ into the mitochondrial...... is positively correlated with intracellular Ca2+ whereas lactate utilization is not. This result lends further support for a significant role of glucose in neuronal bioenergetics and that Ca2+ signalling may control the switch between glucose and lactate utilization during synaptic activity. Based...... on the results, we propose a compartmentalized CiMASH (Ca2+-induced limitation of the MASH) model that includes intracellular compartmentation of glucose and lactate metabolism. We define pre- and post-synaptic compartments metabolizing glucose and glucose plus lactate respectively in which the latter displays...

  17. Pathological Changes of von Economo Neuron and Fork Neuron in Neuropsychiatric Diseases. (United States)

    Liu, Jia; Wang, Lu-ning; Arzberger, Thomas; Zhu, Ming-wei


    von Economo neuron (VEN) is a bipolar neuron characterized by a large spindle-shaped soma. VEN is generally distributed in the layer V of anterior insular lobe and anterior cingulate cortex. Fork neuron is another featured bipolar neuron. In recent years,many studies have illustrated that VEN and fork neurons are correlated with complicated cognition such as self-consciousness and social emotion. Studies in the development and morpholigies of these two neurons as well as their pathological changes in various neurological and psychiatric disorders have found that the abnormal number and functions of VEN can cause corresponding dysfunctions in social recognition and emotions both during the neuro-developmental stages of childhood and during the nerve degeneration in old age stage. Therefore, more attentions should be paid on the research of VEN and fork neurons in neuropsychiatric diseases.

  18. Mirror neurons: from origin to function. (United States)

    Cook, Richard; Bird, Geoffrey; Catmur, Caroline; Press, Clare; Heyes, Cecilia


    This article argues that mirror neurons originate in sensorimotor associative learning and therefore a new approach is needed to investigate their functions. Mirror neurons were discovered about 20 years ago in the monkey brain, and there is now evidence that they are also present in the human brain. The intriguing feature of many mirror neurons is that they fire not only when the animal is performing an action, such as grasping an object using a power grip, but also when the animal passively observes a similar action performed by another agent. It is widely believed that mirror neurons are a genetic adaptation for action understanding; that they were designed by evolution to fulfill a specific socio-cognitive function. In contrast, we argue that mirror neurons are forged by domain-general processes of associative learning in the course of individual development, and, although they may have psychological functions, they do not necessarily have a specific evolutionary purpose or adaptive function. The evidence supporting this view shows that (1) mirror neurons do not consistently encode action "goals"; (2) the contingency- and context-sensitive nature of associative learning explains the full range of mirror neuron properties; (3) human infants receive enough sensorimotor experience to support associative learning of mirror neurons ("wealth of the stimulus"); and (4) mirror neurons can be changed in radical ways by sensorimotor training. The associative account implies that reliable information about the function of mirror neurons can be obtained only by research based on developmental history, system-level theory, and careful experimentation.

  19. Effect of cholecystokinin on experimental neuronal aging

    Institute of Scientific and Technical Information of China (English)

    Xiao-Jiang Sun; Qin-Chi Lu; Yan Cai


    AIM: To observe the effect of cholecystokinin (CCK) on lipofusin value, neuronal dendrite and spine ultrastructure, and total cellular protein during the process of experimental neuronal aging.METHODS: Experimental neuronal aging study model was established by NBA2cellular serum-free culture method. By using single irtracellular lipofusin value from microspectrophotometry,morphology of neuronal dendrites and spines from the scanner electron microscopy, and total cellular protein as the indexes of experimental neuronal aging, we observed the effect of CCK8 on the process of experimental neuronal aging.RESULTS: Under the condition of serum-free culture,intracellular fluorescence value (%) increased with the extension of culture time (1 d 8.51±3.43; 5 d 10.12±3.03;10 d 20.54±10.3; 15 d 36.88±10.49; bP<0.01). When CCK was added to serum-free culture medium, intracellular lipofusin value (%) decreased remarkably after consecutive CCK reaction for 10 and 15 d (control 36.88±10.49; 5 d 32.03±10.01; 10 d 14.37±5.55; 15 d 17.31±4.80; bP<0.01).As the time of serum-free culturing was prolonged, the number of neuronal dendrite and spine cells decreased.The later increased in number when CCK8 was added. CCK8 could improve the total cellular protein in the process of experimental neuronal aging.CONCLUSION: CCK8 may prolong the process of experimental neuronal aging by maintaining the structure and the number of neuronal dendrite and spine cells and changing the total cellular protein.

  20. Bursting and Synchrony in Networks of Model Neurons

    CERN Document Server

    Geier, Christian; Elger, Christian E; Lehnertz, Klaus


    Bursting neurons are considered to be a potential cause of over-excitability and seizure susceptibility. The functional influence of these neurons in extended epileptic networks is still poorly understood. There is mounting evidence that the dynamics of neuronal networks is influenced not only by neuronal and synaptic properties but also by network topology. We investigate numerically the influence of different neuron dynamics on global synchrony in neuronal networks with complex connection topologies.

  1. [Involvement of proteinases produced by both neurons and microglia in neuronal lesion and death pathways]. (United States)

    Nakanishi, H; Yamamoto, K


    Much attention has been paid to proteinases derived from not only neurons but also microglia in relation to neuronal death. There is accumulating evidence that intra- and extracellular proteinases in these cells are part of the basic machinery of neuronal death pathways. Some members of the ced-3/interleukin-1 beta converting enzyme (ICE) (caspase) family of cysteine proteinases have been thought to play a major role in apoptosis of not only non-neuronal cells but also neurons. Calpain has also been demonstrated to be a mediator of the neurodegenerative response. Recent studies have shown that excitotoxic and ischemic neuronal injury could be attenuated by inhibitors of caspases and calpain. Several recent studies have suggested the involvement of endosomal/lysosomal proteinases, including cathepsins B, D and E, in neuronal death induced by excitotoxins and ischemia. Furthermore, it has been reported that the extracellular tissue-type plasminogen activator/plasmin proteolytic cascade is involved in excitotoxic injury of the hippocampal neurons. In addition to such neuronal proteinases, microglial proteinases are believed to be important for the modification of neuronal functions positively or negatively. Cathepsins E and S derived from microglia have been suggested to contribute to neuronal survival through degradation and removal of beta-amyloid, damaged neurons and cellular debris. On the other hand, 6-hydroxydopamine-induced microglial cell death was inhibited by inhibitors of aspartic proteinases and caspases, suggesting the involvement of cathepsins E and D and caspases in microglial cell death. Therefore, identification of which proteinases play a causative role in neuronal death execution and clarification of the regulators and substrates for such proteinases is very important for understanding the molecular basis of the neuronal death pathways and to develop novel neuroprotective agents.

  2. Prevalence of Group A Beta-Hemolytic Streptococcus Oropharyngeal Colonization in Children and Therapeutic Regimen Based on Antistreptolysin Levels: Data from a City From Southern Brazil


    Merlini, Alexandre B; Stocco, Carolina S; Schafranski, Marcelo D; Arruda, Polliane; BAIL, Larissa; Borges, Celso L; Dornelles, Cecília F


    The aim of this study is to determinate the prevalence of oropharyngeal colonization by group A beta-hemolytic Streptococcus (GABHS) in pediatric population of Ponta Grossa, a midsize city of southern Brazil; estimate the effectiveness of antistreptolysin-O (ASO), compared to culture, in presence of infection; and design an unpublished investigative algorithm of rheumatic fever's suspicion, based on needs identified in worldwide consensus. It is an epidemiologic, observational and transversal...

  3. Synthesis and biodistribution of [{sup 11}C]procaterol, a {beta}{sub 2}-adrenoceptor agonist for positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Visser, Ton J.; Wouden, Els A. van der; Waarde, Aren van E-mail:; Doze, Petra; Elsinga, Philip H.; Vaalburg, Willem


    The potent, subtype-selective radioligand ({+-})-erythro-5-(1-hydroxy-2-[{sup 11}C]isopropyl-aminobutyl)-8-hydroxycarbostyri= l ([{sup 11}C]procaterol) was synthesized and evaluated for visualization of pulmonary {beta}{sub 2}-adrenoceptors with positron emission tomography (PET). Procaterol was labelled by reductive alkylation of the desisopropyl precursor with [{sup 11}C]acetone under the influence of NaCNBH{sub 3} and acetic acid. Synthesis and HPLC purification were performed in 34 min. Specific activities ranged from 26.5-39.3 TBq (about 700-1000 Ci)/mmol and the radiochemical yield was 2.4-8.6% (corrected for decay). Biodistribution studies were performed in male Wistar rats which were either untreated or predosed with (D,L)-propranolol hydrochloride ({beta}-adrenoceptor antagonist, 2.5 mg/kg), ICI 118551 ({beta}{sub 2}-adrenoceptor antagonist, 0.15 mg/kg), CGP 20712A ({beta}{sub 1}-adrenoceptor antagonist, 0.15 mg/kg) or isoprenaline ({beta}-adrenoceptor agonist, 15 mg/kg). Specific binding was observed in lungs, spleen and red blood cells, tissues known to contain {beta}{sub 2}-adrenoceptors. Pulmonary binding was blocked by propranolol, ICI 118551 and isoprenaline, but not by CGP 20712A. This binding pattern is consistent with the {beta}{sub 2} selectivity of the adioligand. The clearance of [{sup 11}C]procaterol was biphasic, with a rapid distribution phase (t{sub 1/2} 0.17 min) representing 90% of the injected dose followed by an elimination phase (t{sub 1/2} 18.1 min). About 45% of the plasma radioactivity was unmetabolized procaterol at 15 min postinjection. In a dynamic PET-study, the lungs of untreated control rats could barely be detected and total/non-specific binding ratios rose to only 1.2 at 20 min postinjection. Although labelling and administration of (-) erythro-procaterol, the most active of 4 stereoisomers, may produce better results, [{sup 11}C]procaterol seems unsuitable for {beta}-adrenoceptor imaging.

  4. Neuronal integrative analysis of the "Dumbbell" model for passive neurons. (United States)

    Krzyzanski, Wojciech; Bell, Jonathan; Poznanski, Roman R


    We analyze the so called "Dumbbell" model of Jackson (J. Neurophysiol. 69 (1993) pp. 464) for a single neuron consisting of a patch-clamped cell body attached to dendritic cable of finite length terminating in an oblique derivative ("natural termination") boundary condition representing a dendritic swelling or a natural ending sealed by a continuous surface of the cell membrane. The model is solved analytically via the Green's function method. Large and small time asymptotic behavior of the membrane potential is developed when there is a somatic voltage-clamp imposed. We discuss the difference in the voltage distribution if a sealed-end (Neumann) termination is used instead of the natural termination boundary condition. If the access resistance is large the differences between the potentials corresponding to the two boundary conditions are small at the soma, but can vary significantly near the dendritic termination. This discrepancy is amplified at the soma if there is a synaptic stimulus introduced between the soma and dendritic tip.

  5. Neuronal growth and differentiation on biodegradable membranes. (United States)

    Morelli, Sabrina; Piscioneri, Antonella; Messina, Antonietta; Salerno, Simona; Al-Fageeh, Mohamed B; Drioli, Enrico; De Bartolo, Loredana


    Semipermeable polymeric membranes with appropriate morphological, physicochemical and transport properties are relevant to inducing neural regeneration. We developed novel biodegradable membranes to support neuronal differentiation. In particular, we developed chitosan, polycaprolactone and polyurethane flat membranes and a biosynthetic blend between polycaprolactone and polyurethane by phase-inversion techniques. The biodegradable membranes were characterized in order to evaluate their morphological, physicochemical, mechanical and degradation properties. We investigated the efficacy of these different membranes to promote the adhesion and differentiation of neuronal cells. We employed as model cell system the human neuroblastoma cell line SHSY5Y, which is a well-established system for studying neuronal differentiation. The investigation of viability and specific neuronal marker expression allowed assessment that the correct neuronal differentiation and the formation of neuronal network had taken place in vitro in the cells seeded on different biodegradable membranes. Overall, this study provides evidence that neural cell responses depend on the nature of the biodegradable polymer used to form the membranes, as well as on the dissolution, hydrophilic and, above all, mechanical membrane properties. PCL-PU membranes exhibit mechanical properties that improve neurite outgrowth and the expression of specific neuronal markers.

  6. Sloppiness in spontaneously active neuronal networks. (United States)

    Panas, Dagmara; Amin, Hayder; Maccione, Alessandro; Muthmann, Oliver; van Rossum, Mark; Berdondini, Luca; Hennig, Matthias H


    Various plasticity mechanisms, including experience-dependent, spontaneous, as well as homeostatic ones, continuously remodel neural circuits. Yet, despite fluctuations in the properties of single neurons and synapses, the behavior and function of neuronal assemblies are generally found to be very stable over time. This raises the important question of how plasticity is coordinated across the network. To address this, we investigated the stability of network activity in cultured rat hippocampal neurons recorded with high-density multielectrode arrays over several days. We used parametric models to characterize multineuron activity patterns and analyzed their sensitivity to changes. We found that the models exhibited sloppiness, a property where the model behavior is insensitive to changes in many parameter combinations, but very sensitive to a few. The activity of neurons with sloppy parameters showed faster and larger fluctuations than the activity of a small subset of neurons associated with sensitive parameters. Furthermore, parameter sensitivity was highly correlated with firing rates. Finally, we tested our observations from cell cultures on an in vivo recording from monkey visual cortex and we confirm that spontaneous cortical activity also shows hallmarks of sloppy behavior and firing rate dependence. Our findings suggest that a small subnetwork of highly active and stable neurons supports group stability, and that this endows neuronal networks with the flexibility to continuously remodel without compromising stability and function.

  7. Survival motor neuron protein in motor neurons determines synaptic integrity in spinal muscular atrophy. (United States)

    Martinez, Tara L; Kong, Lingling; Wang, Xueyong; Osborne, Melissa A; Crowder, Melissa E; Van Meerbeke, James P; Xu, Xixi; Davis, Crystal; Wooley, Joe; Goldhamer, David J; Lutz, Cathleen M; Rich, Mark M; Sumner, Charlotte J


    The inherited motor neuron disease spinal muscular atrophy (SMA) is caused by deficient expression of survival motor neuron (SMN) protein and results in severe muscle weakness. In SMA mice, synaptic dysfunction of both neuromuscular junctions (NMJs) and central sensorimotor synapses precedes motor neuron cell death. To address whether this synaptic dysfunction is due to SMN deficiency in motor neurons, muscle, or both, we generated three lines of conditional SMA mice with tissue-specific increases in SMN expression. All three lines of mice showed increased survival, weights, and improved motor behavior. While increased SMN expression in motor neurons prevented synaptic dysfunction at the NMJ and restored motor neuron somal synapses, increased SMN expression in muscle did not affect synaptic function although it did improve myofiber size. Together these data indicate that both peripheral and central synaptic integrity are dependent on motor neurons in SMA, but SMN may have variable roles in the maintenance of these different synapses. At the NMJ, it functions at the presynaptic terminal in a cell-autonomous fashion, but may be necessary for retrograde trophic signaling to presynaptic inputs onto motor neurons. Importantly, SMN also appears to function in muscle growth and/or maintenance independent of motor neurons. Our data suggest that SMN plays distinct roles in muscle, NMJs, and motor neuron somal synapses and that restored function of SMN at all three sites will be necessary for full recovery of muscle power.

  8. Human embryonic stem cell-derived neuronal cells form spontaneously active neuronal networks in vitro. (United States)

    Heikkilä, Teemu J; Ylä-Outinen, Laura; Tanskanen, Jarno M A; Lappalainen, Riikka S; Skottman, Heli; Suuronen, Riitta; Mikkonen, Jarno E; Hyttinen, Jari A K; Narkilahti, Susanna


    The production of functional human embryonic stem cell (hESC)-derived neuronal cells is critical for the application of hESCs in treating neurodegenerative disorders. To study the potential functionality of hESC-derived neurons, we cultured and monitored the development of hESC-derived neuronal networks on microelectrode arrays. Immunocytochemical studies revealed that these networks were positive for the neuronal marker proteins beta-tubulin(III) and microtubule-associated protein 2 (MAP-2). The hESC-derived neuronal networks were spontaneously active and exhibited a multitude of electrical impulse firing patterns. Synchronous bursts of electrical activity similar to those reported for hippocampal neurons and rodent embryonic stem cell-derived neuronal networks were recorded from the differentiated cultures until up to 4 months. The dependence of the observed neuronal network activity on sodium ion channels was examined using tetrodotoxin (TTX). Antagonists for the glutamate receptors NMDA [D(-)-2-amino-5-phosphonopentanoic acid] and AMPA/kainate [6-cyano-7-nitroquinoxaline-2,3-dione], and for GABAA receptors [(-)-bicuculline methiodide] modulated the spontaneous electrical activity, indicating that pharmacologically susceptible neuronal networks with functional synapses had been generated. The findings indicate that hESC-derived neuronal cells can generate spontaneously active networks with synchronous communication in vitro, and are therefore suitable for use in developmental and drug screening studies, as well as for regenerative medicine.

  9. Context-aware modeling of neuronal morphologies

    Directory of Open Access Journals (Sweden)

    Benjamin eTorben-Nielsen


    Full Text Available Neuronal morphologies are pivotal for brain functioning: physical overlap between dendrites and axons constrain the circuit topology, and the precise shape and composition of dendrites determine the integration of inputs to produce an output signal. At the same time, morphologies are highly diverse and variant. The variance, presumably, originates from neurons developing in a densely packed brain substrate where they interact (e.g., repulsion or attraction with other actors in this substrate. However, when studying neurons their context is never part of the analysis and they are treated as if they existed in isolation.Here we argue that to fully understand neuronal morphology and its variance it is important to consider neurons in relation to each other and to other actors in the surrounding brain substrate, i.e., their context. We propose a context-aware computational framework, NeuroMaC, in which large numbers of neurons can be grown simultaneously according to growth rules expressed in terms of interactions between the developing neuron and the surrounding brain substrate.As a proof of principle, we demonstrate that by using NeuroMaC we can generate accurate virtual morphologies of distinct classes both in isolation and as part of neuronal forests. Accuracy is validated against population statistics of experimentally reconstructed morphologies. We show that context-aware generation of neurons can explain characteristics of variation. Indeed, plausible variation is an inherent property of the morphologies generated by context-aware rules. We speculate about the applicability of this framework to investigate morphologies and circuits, to classify healthy and pathological morphologies, and to generate large quantities of morphologies for large-scale modeling.

  10. Culturing conditions determine neuronal and glial excitability. (United States)

    Stoppelkamp, Sandra; Riedel, Gernot; Platt, Bettina


    The cultivation of pure neuronal cultures is considered advantageous for the investigation of cell-type specific responses (such as transmitter release and also pharmacological agents), however, divergent results are a likely consequence of media modifications and culture composition. Using Fura-2 based imaging techniques, we here set out to compare calcium responses of rat hippocampal neurones and glia to excitatory stimulation with l-glutamate in different culture types and media. Neurones in neurone-enriched cultures had increased responses to 10 μM and 100 μM l-glutamate (+43 and 45%, respectively; p's< 0.001) and a slower recovery compared to mixed cultures, indicating heightened excitability. In matured (15-20 days in vitro) mixed cultures, neuronal responder rates were suppressed in a neurone-supportive medium (Neurobasal-A, NB: 65%) compared to a general-purpose medium (supplemented minimal essential medium, MEM: 96%). Glial response size in contrast did not differ greatly in isolated or mixed cultures maintained in MEM, but responder rates were suppressed in both culture types in NB (e.g. 10 μM l-glutamate responders in mixed cultures: 29% in NB, 71% in MEM). This indicates that medium composition is more important for glial excitability than the presence of neurones, whereas the presence of glia has an important impact on neuronal excitability. Therefore, careful consideration of culturing conditions is crucial for interpretation and comparison of experimental results. Especially for investigations of toxicity and neuroprotection mixed cultures may be more physiologically relevant over isolated cultures as they comprise aspects of mutual influences between glia and neurones.

  11. Reaction-Diffusion in the NEURON Simulator

    Directory of Open Access Journals (Sweden)

    Robert A. McDougal


    Full Text Available In order to support research on the role of cell biological principles (genomics, proteomics, signaling cascades and reaction dynamics on the dynamics of neuronal response in health and disease, NEURON has developed a Reaction-Diffusion (rxd module in Python which provides specification and simulation for these dynamics, coupled with the electrophysiological dynamics of the cell membrane. Arithmetic operations on species and parameters are overloaded, allowing arbitrary reaction formulas to be specified using Python syntax. These expressions are then transparently compiled into bytecode that uses NumPy for fast vectorized calculations. At each time step, rxd combines NEURON's integrators with SciPy’s sparse linear algebra library.

  12. Statistical Mechanics Characterization of Neuronal Mosaics

    CERN Document Server

    Costa, Luciano da Fontoura; de Lima, Silene Maria Araujo


    The spatial distribution of neuronal cells is an important requirement for achieving proper neuronal function in several parts of the nervous system of most animals. For instance, specific distribution of photoreceptors and related neuronal cells, particularly the ganglion cells, in mammal's retina is required in order to properly sample the projected scene. This work presents how two concepts from the areas of statistical mechanics and complex systems, namely the \\emph{lacunarity} and the \\emph{multiscale entropy} (i.e. the entropy calculated over progressively diffused representations of the cell mosaic), have allowed effective characterization of the spatial distribution of retinal cells.

  13. Tracing lineages to uncover neuronal identity

    Directory of Open Access Journals (Sweden)

    Perlmann Thomas


    Full Text Available Abstract Many previous studies have focused on understanding how midbrain dopamine neurons, which are implicated in many neurological conditions, are generated during embryogenesis. One of the remaining questions concerns how different dopamine neuron subtypes are specified. A recent paper in Neural Development has revealed features of a spatial and temporal lineage map that, together with other studies, begins to elucidate the developmental origin of distinct neuronal subtypes within the developing midbrain. See research article

  14. Reaction-diffusion in the NEURON simulator. (United States)

    McDougal, Robert A; Hines, Michael L; Lytton, William W


    In order to support research on the role of cell biological principles (genomics, proteomics, signaling cascades and reaction dynamics) on the dynamics of neuronal response in health and disease, NEURON's Reaction-Diffusion (rxd) module in Python provides specification and simulation for these dynamics, coupled with the electrophysiological dynamics of the cell membrane. Arithmetic operations on species and parameters are overloaded, allowing arbitrary reaction formulas to be specified using Python syntax. These expressions are then transparently compiled into bytecode that uses NumPy for fast vectorized calculations. At each time step, rxd combines NEURON's integrators with SciPy's sparse linear algebra library.

  15. Reverberatory activity in neuronal networks in vitro

    Institute of Scientific and Technical Information of China (English)

    LAU PakMing; BI GuoQiang


    It has been proposed that during cognitive processes, "online" memory traces in the brain are carried by reverberatory activity in neuronal circuits. However, the nature of such reverberation has remained elusive from experimental studies, largely due to the enormous complexity of intact circuits. Recent works have attempted to address this issue using cultured neuronal network and have revealed new dynamic properties of network reverberation as well as the underlying cellular mechanisms. These results demonstrate the effectiveness of in vitro networks as a useful tool for mechanistic dissection of neuronal circuit dynamics.

  16. Neuronal Alignment On Asymmetric Textured Surfaces

    CERN Document Server

    Beighley, Ross; Sekeroglu, Koray; Atherton, Timothy; Demirel, Melik C; Staii, Cristian


    Axonal growth and the formation of synaptic connections are key steps in the development of the nervous system. Here we present experimental and theoretical results on axonal growth and interconnectivity in order to elucidate some of the basic rules that neuronal cells use for functional connections with one another. We demonstrate that a unidirectional nanotextured surface can bias axonal growth. We perform a systematic investigation of neuronal processes on asymmetric surfaces and quantify the role that biomechanical surface cues play in neuronal growth. These results represent an important step towards engineering directed axonal growth for neuro-regeneration studies.

  17. Neuroimaging of motor neuron diseases. (United States)

    Kassubek, Jan; Ludolph, Albert C; Müller, Hans-Peter


    It is agreed that conventional magnetic resonance imaging (MRI) of the brain and spine is one of the core elements in the differential diagnostic work up of patients with clinical signs of motor neuron diseases (MNDs), for example amyotrophic lateral sclerosis (ALS), to exclude MND mimics. However, the sensitivity and specificity of MRI signs in these disorders are moderate to low and do not have an evidence level higher than class IV (good clinical practice point). Currently computerized MRI analyses in ALS and other MNDs are not techniques used for individual diagnosis. However, they have improved the anatomical understanding of pathomorphological alterations in gray and white matter in various MNDs and the changes in functional networks by quantitative comparisons between patients with MND and controls at group level. For multiparametric MRI protocols, including T1-weighted three-dimensional datasets, diffusion-weighted imaging and functional MRI, the potential as a 'dry' surrogate marker is a subject of investigation in natural history studies with well defined patients. The additional value of MRI with respect to early diagnosis at an individual level and for future disease-modifying multicentre trials remains to be defined. There is still the need for more longitudinal studies in the very early stages of disease or when there is clinical uncertainty and for better standardization in the acquisition and postprocessing of computer-based MRI data. These requirements are to be addressed by establishing quality-controlled multicentre neuroimaging databases.

  18. Cellular and molecular neuronal plasticity. (United States)

    Griesbach, Grace S; Hovda, David A


    The brain has the capability to adapt to function when tissue is compromised. This capability of adaptation paves the road to recovery and allows for rehabilitation after a traumatic brain injury (TBI). This chapter addresses neuroplasticity within the context of TBI. Here neuroplasticity is defined as changes in neuronal structure and function, including synaptic changes as well as modifications in neural pathways. First, the influence of TBI pathology on neuroplasticity is addressed. Here, proteins that are important in neuroplasticity are introduced and a description given of how these are affected in a temporal and severity-dependent manner. Secondly, given that we are becoming increasingly aware that the brain's response to injury is highly influenced by the environmental milieu, the manner in which behavioral manipulations have an effect on TBI-associated neuroplasticity is addressed. A description is given of how specific environmental qualities may facilitate or hinder neuroplasticity. Finally, the long-term effects of neuroplasticity and the relevance it has to rehabilitation are described.

  19. The ontogenetic origins of mirror neurons: evidence from 'tool-use' and 'audiovisual' mirror neurons. (United States)

    Cook, Richard


    Since their discovery, mirror neurons--units in the macaque brain that discharge both during action observation and execution--have attracted considerable interest. Whether mirror neurons are an innate endowment or acquire their sensorimotor matching properties ontogenetically has been the subject of intense debate. It is widely believed that these units are an innate trait; that we are born with a set of mature mirror neurons because their matching properties conveyed upon our ancestors an evolutionary advantage. However, an alternative view is that mirror neurons acquire their matching properties during ontogeny, through correlated experience of observing and performing actions. The present article re-examines frequently overlooked neurophysiological reports of 'tool-use' and 'audiovisual' mirror neurons within the context of this debate. It is argued that these findings represent compelling evidence that mirror neurons are a product of sensorimotor experience, and not an innate endowment.

  20. Epibranchial placode-derived neurons produce BDNF required for early sensory neuron development. (United States)

    Harlow, Danielle E; Yang, Hui; Williams, Trevor; Barlow, Linda A


    In mice, BDNF provided by the developing taste epithelium is required for gustatory neuron survival following target innervation. However, we find that expression of BDNF, as detected by BDNF-driven β-galactosidase, begins in the cranial ganglia before its expression in the central (hindbrain) or peripheral (taste papillae) targets of these sensory neurons, and before gustatory ganglion cells innervate either target. To test early BDNF function, we examined the ganglia of bdnf null mice before target innervation, and found that while initial neuron survival is unaltered, early neuron development is disrupted. In addition, fate mapping analysis in mice demonstrates that murine cranial ganglia arise from two embryonic populations, i.e., epibranchial placodes and neural crest, as has been described for these ganglia in non-mammalian vertebrates. Only placodal neurons produce BDNF, however, which indicates that prior to innervation, early ganglionic BDNF produced by placode-derived cells promotes gustatory neuron development.

  1. Regulation of neuronal axon specification by glia-neuron gap junctions in C. elegans (United States)

    Meng, Lingfeng; Zhang, Albert; Jin, Yishi; Yan, Dong


    Axon specification is a critical step in neuronal development, and the function of glial cells in this process is not fully understood. Here, we show that C. elegans GLR glial cells regulate axon specification of their nearby GABAergic RME neurons through GLR-RME gap junctions. Disruption of GLR-RME gap junctions causes misaccumulation of axonal markers in non-axonal neurites of RME neurons and converts microtubules in those neurites to form an axon-like assembly. We further uncover that GLR-RME gap junctions regulate RME axon specification through activation of the CDK-5 pathway in a calcium-dependent manner, involving a calpain clp-4. Therefore, our study reveals the function of glia-neuron gap junctions in neuronal axon specification and shows that calcium originated from glial cells can regulate neuronal intracellular pathways through gap junctions. DOI: PMID:27767956

  2. Genetic strategies to investigate neuronal circuit properties using stem cell-derived neurons

    Directory of Open Access Journals (Sweden)

    Isabella eGarcia


    Full Text Available The mammalian brain is anatomically and functionally complex, and prone to diverse forms of injury and neuropathology. Scientists have long strived to develop cell replacement therapies to repair damaged and diseased nervous tissue. However, this goal has remained unrealized for various reasons, including nascent knowledge of neuronal development, the inability to track and manipulate transplanted cells within complex neuronal networks, and host graft rejection. Recent advances in embryonic stem cell (ESC and induced pluripotent stem cell (iPSC technology, alongside novel genetic strategies to mark and manipulate stem cell-derived neurons now provide unprecedented opportunities to investigate complex neuronal circuits in both healthy and diseased brains. Here, we review current technologies aimed at generating and manipulating neurons derived from ESCs and iPSCs towards investigation and manipulation of complex neuronal circuits, ultimately leading to the design and development of novel cell-based therapeutic approaches.

  3. Frizzled-5 Receptor Is Involved in Neuronal Polarity and Morphogenesis of Hippocampal Neurons (United States)

    Slater, Paula G.; Ramirez, Valerie T.; Gonzalez-Billault, Christian; Varela-Nallar, Lorena; Inestrosa, Nibaldo C.


    The Wnt signaling pathway plays important roles during different stages of neuronal development, including neuronal polarization and dendritic and axonal outgrowth. However, little is known about the identity of the Frizzled receptors mediating these processes. In the present study, we investigated the role of Frizzled-5 (Fzd5) on neuronal development in cultured Sprague-Dawley rat hippocampal neurons. We found that Fzd5 is expressed early in cultured neurons on actin-rich structures localized at minor neurites and axonal growth cones. At 4 DIV, Fzd5 polarizes towards the axon, where its expression is detected mainly at the peripheral zone of axonal growth cones, with no obvious staining at dendrites; suggesting a role of Fzd5 in neuronal polarization. Overexpression of Fzd5 during the acquisition of neuronal polarity induces mislocalization of the receptor and a loss of polarized axonal markers. Fzd5 knock-down leads to loss of axonal proteins, suggesting an impaired neuronal polarity. In contrast, overexpression of Fzd5 in neurons that are already polarized did not alter polarity, but decreased the total length of axons and increased total dendrite length and arborization. Fzd5 activated JNK in HEK293 cells and the effects triggered by Fzd5 overexpression in neurons were partially prevented by inhibition of JNK, suggesting that a non-canonical Wnt signaling mechanism might be involved. Our results suggest that, Fzd5 has a role in the establishment of neuronal polarity, and in the morphogenesis of neuronal processes, in part through the activation of the non-canonical Wnt mechanism involving JNK. PMID:24205342

  4. Frizzled-5 receptor is involved in neuronal polarity and morphogenesis of hippocampal neurons.

    Directory of Open Access Journals (Sweden)

    Paula G Slater

    Full Text Available The Wnt signaling pathway plays important roles during different stages of neuronal development, including neuronal polarization and dendritic and axonal outgrowth. However, little is known about the identity of the Frizzled receptors mediating these processes. In the present study, we investigated the role of Frizzled-5 (Fzd5 on neuronal development in cultured Sprague-Dawley rat hippocampal neurons. We found that Fzd5 is expressed early in cultured neurons on actin-rich structures localized at minor neurites and axonal growth cones. At 4 DIV, Fzd5 polarizes towards the axon, where its expression is detected mainly at the peripheral zone of axonal growth cones, with no obvious staining at dendrites; suggesting a role of Fzd5 in neuronal polarization. Overexpression of Fzd5 during the acquisition of neuronal polarity induces mislocalization of the receptor and a loss of polarized axonal markers. Fzd5 knock-down leads to loss of axonal proteins, suggesting an impaired neuronal polarity. In contrast, overexpression of Fzd5 in neurons that are already polarized did not alter polarity, but decreased the total length of axons and increased total dendrite length and arborization. Fzd5 activated JNK in HEK293 cells and the effects triggered by Fzd5 overexpression in neurons were partially prevented by inhibition of JNK, suggesting that a non-canonical Wnt signaling mechanism might be involved. Our results suggest that, Fzd5 has a role in the establishment of neuronal polarity, and in the morphogenesis of neuronal processes, in part through the activation of the non-canonical Wnt mechanism involving JNK.

  5. Reconstruction of phrenic neuron identity in embryonic stem cell-derived motor neurons. (United States)

    Machado, Carolina Barcellos; Kanning, Kevin C; Kreis, Patricia; Stevenson, Danielle; Crossley, Martin; Nowak, Magdalena; Iacovino, Michelina; Kyba, Michael; Chambers, David; Blanc, Eric; Lieberam, Ivo


    Air breathing is an essential motor function for vertebrates living on land. The rhythm that drives breathing is generated within the central nervous system and relayed via specialised subsets of spinal motor neurons to muscles that regulate lung volume. In mammals, a key respiratory muscle is the diaphragm, which is innervated by motor neurons in the phrenic nucleus. Remarkably, relatively little is known about how this crucial subtype of motor neuron is generated during embryogenesis. Here, we used direct differentiation of motor neurons from mouse embryonic stem cells as a tool to identify genes that direct phrenic neuron identity. We find that three determinants, Pou3f1, Hoxa5 and Notch, act in combination to promote a phrenic neuron molecular identity. We show that Notch signalling induces Pou3f1 in developing motor neurons in vitro and in vivo. This suggests that the phrenic neuron lineage is established through a local source of Notch ligand at mid-cervical levels. Furthermore, we find that the cadherins Pcdh10, which is regulated by Pou3f1 and Hoxa5, and Cdh10, which is controlled by Pou3f1, are both mediators of like-like clustering of motor neuron cell bodies. This specific Pcdh10/Cdh10 activity might provide the means by which phrenic neurons are assembled into a distinct nucleus. Our study provides a framework for understanding how phrenic neuron identity is conferred and will help to generate this rare and inaccessible yet vital neuronal subtype directly from pluripotent stem cells, thus facilitating subsequent functional investigations.

  6. Sexually dimorphic neuronal responses to social isolation (United States)

    Senst, Laura; Baimoukhametova, Dinara; Sterley, Toni-Lee; Bains, Jaideep Singh


    Many species use social networks to buffer the effects of stress. The mere absence of a social network, however, may also be stressful. We examined neuroendocrine, PVN CRH neurons and report that social isolation alters the intrinsic properties of these cells in sexually dimorphic fashion. Specifically, isolating preadolescent female mice from littermates for neurons. These changes were not evident in age-matched males. By contrast, subjecting either males (isolated or grouped) or group housed females to acute physical stress (swim), increased FSL. The increase in FSL following either social isolation or acute physical stress was blocked by the glucocorticoid synthesis inhibitor, metyrapone and mimicked by exogenous corticosterone. The increase in FSL results in a decrease in the excitability of CRH neurons. Our observations demonstrate that social isolation, but not acute physical stress has sex-specific effects on PVN CRH neurons. DOI: PMID:27725087

  7. Tunable Oscillations in the Purkinje Neuron

    CERN Document Server

    Abrams, Ze'ev R; Wang, Yuan; Trauner, Dirk; Zhang, Xiang


    In this paper, we study the dynamics of slow oscillations in Purkinje neurons in vitro, and derive a strong association with a forced parametric oscillator model. We demonstrate the precise rhythmicity of the oscillations in Purkinje neurons, as well as a dynamic tunability of this oscillation using a photo-switchable compound. We show that this slow oscillation can be induced in every Purkinje neuron, having periods ranging between 10-25 seconds. Starting from a Hodgkin-Huxley model, we also demonstrate that this oscillation can be externally modulated, and that the neurons will return to their intrinsic firing frequency after the forced oscillation is concluded. These results signify an additional functional role of tunable oscillations within the cerebellum, as well as a dynamic control of a time scale in the brain in the range of seconds.

  8. Managing Brain Extracellular K(+) during Neuronal Activity

    DEFF Research Database (Denmark)

    Larsen, Brian Roland; Stoica, Anca; MacAulay, Nanna


    During neuronal activity in the brain, extracellular K(+) rises and is subsequently removed to prevent a widespread depolarization. One of the key players in regulating extracellular K(+) is the Na(+)/K(+)-ATPase, although the relative involvement and physiological impact of the different subunit...... isoform compositions of the Na(+)/K(+)-ATPase remain unresolved. The various cell types in the brain serve a certain temporal contribution in the face of network activity; astrocytes respond directly to the immediate release of K(+) from neurons, whereas the neurons themselves become the primary K......(+) absorbers as activity ends. The kinetic characteristics of the catalytic α subunit isoforms of the Na(+)/K(+)-ATPase are, partly, determined by the accessory β subunit with which they combine. The isoform combinations expressed by astrocytes and neurons, respectively, appear to be in line with the kinetic...

  9. BDNF signaling and survival of striatal neurons

    Directory of Open Access Journals (Sweden)

    Maryna eBaydyuk


    Full Text Available The striatum, a major component of the basal ganglia, performs multiple functions including control of movement, reward, and addiction. Dysfunction and death of striatal neurons are the main causes for the motor disorders associated with Huntington’s disease (HD. Brain-derived neurotrophic factor (BDNF, a member of the neurotrophin family, is among factors that promote survival and proper function of this neuronal population. Here, we review recent studies showing that BDNF determines the size of the striatum by supporting survival of the immature striatal neurons at their origin, promotes maturation of striatal neurons, and facilitates establishment of striatal connections during brain development. We also examine the role of BDNF in maintaining proper function of the striatum during adulthood, summarize the mechanisms that lead to a deficiency in BDNF signaling and subsequently striatal degeneration in HD, and highlight a potential role of BDNF as a therapeutic target for HD treatment.

  10. Control and Synchronization of Neuron Ensembles

    CERN Document Server

    Li, Jr-Shin; Ruths, Justin


    Synchronization of oscillations is a phenomenon prevalent in natural, social, and engineering systems. Controlling synchronization of oscillating systems is motivated by a wide range of applications from neurological treatment of Parkinson's disease to the design of neurocomputers. In this article, we study the control of an ensemble of uncoupled neuron oscillators described by phase models. We examine controllability of such a neuron ensemble for various phase models and, furthermore, study the related optimal control problems. In particular, by employing Pontryagin's maximum principle, we analytically derive optimal controls for spiking single- and two-neuron systems, and analyze the applicability of the latter to an ensemble system. Finally, we present a robust computational method for optimal control of spiking neurons based on pseudospectral approximations. The methodology developed here is universal to the control of general nonlinear phase oscillators.

  11. Fitting Neuron Models to Spike Trains (United States)

    Rossant, Cyrille; Goodman, Dan F. M.; Fontaine, Bertrand; Platkiewicz, Jonathan; Magnusson, Anna K.; Brette, Romain


    Computational modeling is increasingly used to understand the function of neural circuits in systems neuroscience. These studies require models of individual neurons with realistic input–output properties. Recently, it was found that spiking models can accurately predict the precisely timed spike trains produced by cortical neurons in response to somatically injected currents, if properly fitted. This requires fitting techniques that are efficient and flexible enough to easily test different candidate models. We present a generic solution, based on the Brian simulator (a neural network simulator in Python), which allows the user to define and fit arbitrary neuron models to electrophysiological recordings. It relies on vectorization and parallel computing techniques to achieve efficiency. We demonstrate its use on neural recordings in the barrel cortex and in the auditory brainstem, and confirm that simple adaptive spiking models can accurately predict the response of cortical neurons. Finally, we show how a complex multicompartmental model can be reduced to a simple effective spiking model. PMID:21415925

  12. The Neuronal Network Orchestration behind Motor Behaviors

    DEFF Research Database (Denmark)

    Petersen, Peter Christian

    In biological networks, millions of neurons organize themselves from microscopic noisy individuals to robust macroscopic entities. These entities are capable of producing higher functions like sensory processing, decision-making, and elaborate behavioral responses. Every aspect of these behaviors...... is the outcome of an advanced orchestration of the activity of populations of neurons. Through spiking activity, neurons are able to interact; yet we know little about how this interaction occurs in spinal networks. How is the activity distributed across the population? What is the composition of synaptic input...... that is received by the individual neurons and how is the synaptic input processed? This thesis focuses on aspects of these questions for spinal networks involved in the generation of stereotypical motor behaviors. The thesis consists of two studies. In the first study, I investigated the synaptic input...

  13. The Age of Human Cerebral Cortex Neurons

    Energy Technology Data Exchange (ETDEWEB)

    Bhardwaj, R D; Curtis, M A; Spalding, K L; Buchholz, B A; Fink, D; Bjork-Eriksson, T; Nordborg, C; Gage, F H; Druid, H; Eriksson, P S; Frisen, J


    The traditional static view of the adult mammalian brain has been challenged by the realization of continuous generation of neurons from stem cells. Based mainly on studies in experimental animals, adult neurogenesis may contribute to recovery after brain insults and decreased neurogenesis has been implicated in the pathogenesis of neurological and psychiatric diseases in man. The extent of neurogenesis in the adult human brain has, however, been difficult to establish. We have taken advantage of the integration of {sup 14}C, generated by nuclear bomb tests during the Cold War, in DNA to establish the age of neurons in the major areas of the human cerebral cortex. Together with the analysis of the cortex from patients who received BrdU, which integrates in the DNA of dividing cells, our results demonstrate that whereas non-neuronal cells turn over, neurons in the human cerebral cortex are not generated postnatally at detectable levels, but are as old as the individual.

  14. Controlling neuronal noise using chaos control

    CERN Document Server

    Christini, D J; Christini, David J; Collins, James J


    Chaos control techniques have been applied to a wide variety of experimental systems, including magneto-elastic ribbons, lasers, chemical reactions, arrhythmic cardiac tissue, and spontaneously bursting neuronal networks. An underlying assumption in all of these studies is that the system being controlled is chaotic. However, the identification of chaos in experimental systems, particularly physiological systems, is a difficult and often misleading task. Here we demonstrate that the chaos criteria used in a recent study can falsely classify a noise-driven, non-chaotic neuronal model as being chaotic. We apply chaos control, periodic pacing, and anticontrol to the non-chaotic model and obtain results which are similar to those reported for apparently chaotic, {\\em in vitro} neuronal networks. We also obtain similar results when we apply chaos control to a simple stochastic system. These novel findings challenge the claim that the aforementioned neuronal networks were chaotic and suggest that chaos control tech...

  15. Lyapunov exponents computation for hybrid neurons. (United States)

    Bizzarri, Federico; Brambilla, Angelo; Gajani, Giancarlo Storti


    Lyapunov exponents are a basic and powerful tool to characterise the long-term behaviour of dynamical systems. The computation of Lyapunov exponents for continuous time dynamical systems is straightforward whenever they are ruled by vector fields that are sufficiently smooth to admit a variational model. Hybrid neurons do not belong to this wide class of systems since they are intrinsically non-smooth owing to the impact and sometimes switching model used to describe the integrate-and-fire (I&F) mechanism. In this paper we show how a variational model can be defined also for this class of neurons by resorting to saltation matrices. This extension allows the computation of Lyapunov exponent spectrum of hybrid neurons and of networks made up of them through a standard numerical approach even in the case of neurons firing synchronously.

  16. Transient Synchronization in Complex Neuronal Networks

    CERN Document Server

    Costa, Luciano da Fontoura


    Transient synchronization in complex neuronal networks as a consequence of activation-conserved dynamics induced by having sources placed at specific neurons is investigated. The basic integrate-and-fire neuron is adopted, and the dynamics is estimated computationally so as to obtain the activation at each node along each instant of time. The dynamics is implemented so as to conserve the total activation entering the system, which is a distinctive feature of the current work. The synchronization of the activation of the network is then quantified along time in terms of its normalized instantaneous entropy. The potential of such concepts and measurements is explored with respect to 6 theoretical models, as well as for the neuronal network of \\emph{C. elegans}. A series of interesting results are obtained and discussed, including the fact that all models led to a transient period of synchronization, whose specific features depend heavily on the topological features of the networks.

  17. Integrated microfluidic platforms for investigating neuronal networks (United States)

    Kim, Hyung Joon

    This dissertation describes the development and application of integrated microfluidics-based assay platforms to study neuronal activities in the nervous system in-vitro. The assay platforms were fabricated using soft lithography and micro/nano fabrication including microfluidics, surface patterning, and nanomaterial synthesis. The use of integrated microfluidics-based assay platform allows culturing and manipulating many types of neuronal tissues in precisely controlled microenvironment. Furthermore, they provide organized multi-cellular in-vitro model, long-term monitoring with live cell imaging, and compatibility with molecular biology techniques and electrophysiology experiment. In this dissertation, the integrated microfluidics-based assay platforms are developed for investigation of neuronal activities such as local protein synthesis, impairment of axonal transport by chemical/physical variants, growth cone path finding under chemical/physical cues, and synaptic transmission in neuronal circuit. Chapter 1 describes the motivation, objectives, and scope for developing in-vitro platform to study various neuronal activities. Chapter 2 introduces microfluidic culture platform for biochemical assay with large-scale neuronal tissues that are utilized as model system in neuroscience research. Chapter 3 focuses on the investigation of impaired axonal transport by beta-Amyloid and oxidative stress. The platform allows to control neuronal processes and to quantify mitochondrial movement in various regions of axons away from applied drugs. Chapter 4 demonstrates the development of microfluidics-based growth cone turning assay to elucidate the mechanism underlying axon guidance under soluble factors and shear flow. Using this platform, the behaviors of growth cone of mammalian neurons are verified under the gradient of inhibitory molecules and also shear flow in well-controlled manner. In Chapter 5, I combine in-vitro multicellular model with microfabricated MEA

  18. Authors’ response: mirror neurons: tests and testability. (United States)

    Catmur, Caroline; Press, Clare; Cook, Richard; Bird, Geoffrey; Heyes, Cecilia


    Commentators have tended to focus on the conceptual framework of our article, the contrast between genetic and associative accounts of mirror neurons, and to challenge it with additional possibilities rather than empirical data. This makes the empirically focused comments especially valuable. The mirror neuron debate is replete with ideas; what it needs now are system-level theories and careful experiments – tests and testability.