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Sample records for adult drg neurons

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

    PubMed Central

    2010-01-01

    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 < 0.05), compared to controls (120.3 ± 4 a.u.). Calcium imaging showed significantly enhanced capsaicin (TRPV1 agonist), responses after acute 20 μg/ml oxaliplatin treatment where the second of paired capsaicin responses increased from 80.7 ± 0.6% without oxaliplatin, to 171.26 ± 29% with oxaliplatin, (n = 6 paired t test, P < 0.05); this was reduced to 81.42 ± 8.1% (P < 0.05), by pretretreatment with the cannabinoid CB2 receptor agonist GW 833972. Chronic oxaliplatin treatment also resulted in dose related increases in capsaicin responses. Similarly, second responses to icilin (TRPA1/TRPM8 agonist), were enhanced after acute (143.85 ± 7%, P = 0.004, unpaired t test, n = 3), and chronic (119.7 ± 11.8%, P < 0.05, n = 3) oxaliplatin treatment, compared to control (85.3 ± 1.7%). Responses to the selective TRPM8 agonist WS-12 were not affected. 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. PMID:21106058

  2. CFTR mediates noradrenaline-induced ATP efflux from DRG neurons

    PubMed Central

    2011-01-01

    In our earlier study, noradrenaline (NA) stimulated ATP release from dorsal root ganglion (DRG) neurons as mediated via β3 adrenoceptors linked to Gs protein involving protein kinase A (PKA) activation, to cause allodynia. The present study was conducted to understand how ATP is released from DRG neurons. In an outside-out patch-clamp configuration from acutely dissociated rat DRG neurons, single-channel currents, sensitive to the P2X receptor inhibitor PPADS, were evoked by approaching the patch-electrode tip close to a neuron, indicating that ATP is released from DRG neurons, to activate P2X receptor. NA increased the frequency of the single-channel events, but such NA effect was not found for DRG neurons transfected with the siRNA to silence the cystic fibrosis transmembrane conductance regulator (CFTR) gene. In the immunocytochemical study using acutely dissociated rat DRG cells, CFTR was expressed in neurons alone, but not satellite cells, fibroblasts, or Schwann cells. It is concluded from these results that CFTR mediates NA-induced ATP efflux from DRG neurons as an ATP channel. PMID:21943397

  3. NGF rescues DRG neurons in vitro from oxidative damage produced by hemodialyzers.

    PubMed

    Podratz, Jewel L; Windebank, Anthony J

    2005-06-01

    Using dorsal root ganglion neurons (DRG), in vitro, we studied the effects of nerve growth factor (NGF) on a toxin extracted from ethylene oxide (EO) sterilized hemodialyzers. Tissue culture medium passed through dialyzers produced beading of DRG axons that was inhibited by increasing the concentration of NGF from 3.5 to 10 ng/ml. The antioxidant enzymes, catalase and glutathione peroxidase (GPx), prevented neurite beading while superoxide dismutase (SOD) alone did not. 3-amino-1,2,4-triazole (Az), an inhibitor of catalase blocked the protective effects of catalase and NGF. 1,3 bis[chloromethyl]-1-nitrosourea (BCNU) inhibits glutathione reductase, and reduces intracellular glutathione levels; it blocked the protective effects of NGF. Dialyzer treated medium was found to have increased peroxide content. In parallel experiments, NGF protected DRG neurons from hydrogen peroxide (H(2)O(2)) toxicity that was inhibited by Az and BCNU. NGF was also shown to upregulate glutathione in DRG neurons. We propose that EO gas used in the sterilization of hemodialyzers is responsible for the neurotoxicity and is most likely due to oxidative damage in DRG neurons. NGF protects DRG from this toxin by upregulating antioxidants such as catalase, GPx and GSH. PMID:15935206

  4. Metabolic changes of cultured DRG neurons induced by adenosine using confocal microscopy imaging

    NASA Astrophysics Data System (ADS)

    Zheng, Liqin; Huang, Yimei; Chen, Jiangxu; Wang, Yuhua; Yang, Hongqin; Zhang, Yanding; Xie, Shusen

    2012-12-01

    Adenosine exerts multiple effects on pain transmission in the peripheral nervous system. This study was performed to use confocal microscopy to evaluate whether adenosine could affect dorsal root ganglia (DRG) neurons in vitro and test which adenosine receptor mediates the effect of adenosine on DRG neurons. After adding adenosine with different concentration, we compared the metabolic changes by the real time imaging of calcium and mitochondria membrane potential using confocal microscopy. The results showed that the effect of 500 μM adenosine on the metabolic changes of DRG neurons was more significant than others. Furthermore, four different adenosine receptor antagonists were used to study which receptor mediated the influences of adenosine on the cultured DRG neurons. All adenosine receptor antagonists especially A1 receptor antagonist (DPCPX) had effect on the Ca2+ and mitochondria membrane potential dynamics of DRG neurons. The above studies demonstrated that the effect of adenosine which may be involved in the signal transmission on the sensory neurons was dose-dependent, and all the four adenosine receptors especially the A1R may mediate the transmission.

  5. Semaphorin 3A and neurotrophins: a balance between apoptosis and survival signaling in embryonic DRG neurons.

    PubMed

    Ben-Zvi, Ayal; Yagil, Zohar; Hagalili, Yamit; Klein, Hagit; Lerman, Omer; Behar, Oded

    2006-01-01

    Large numbers of neurons are eliminated by apoptosis during nervous system development. For instance, in the mouse dorsal root ganglion (DRG), the highest incidence of cell death occurs between embryonic days 12 and 14 (E12-E14). While the cause of cell death and its biological significance in the nervous system is not entirely understood, it is generally believed that limiting quantities of neurotrophins are responsible for neuronal death. Between E12 and E14, developing DRG neurons pass through tissues expressing high levels of axonal guidance molecules such as Semaphorin 3A (Sema3A) while navigating to their targets. Here, we demonstrate that Sema3A acts as a death-inducing molecule in neurotrophin-3 (NT-3)-, brain-derived neurotrophic factor (BDNF)- and nerve growth factor (NGF)-dependent E12 and E13 cultured DRG neurons. We show that Sema3A most probably induces cell death through activation of the c-Jun N-terminal kinase (JNK)/c-Jun signaling pathway, and that this cell death is blocked by a moderate increase in NGF concentration. Interestingly, increasing concentrations of other neurotrophic factors, such as NT-3 or BDNF, do not elicit similar effects. Our data suggest that the number of DRG neurons is determined by a fine balance between neurotrophins and Semaphorin 3A, and not only by neurotrophin levels. PMID:16336628

  6. Mycolactone-mediated neurite degeneration and functional effects in cultured human and rat DRG neurons

    PubMed Central

    Sinisi, M; Fox, M; MacQuillan, A; Quick, T; Korchev, Y; Bountra, C; McCarthy, T; Anand, P

    2016-01-01

    Background Mycolactone is a polyketide toxin secreted by the mycobacterium Mycobacterium ulcerans, responsible for the extensive hypoalgesic skin lesions characteristic of patients with Buruli ulcer. A recent pre-clinical study proposed that mycolactone may produce analgesia via activation of the angiotensin II type 2 receptor (AT2R). In contrast, AT2R antagonist EMA401 has shown analgesic efficacy in animal models and clinical trials for neuropathic pain. We therefore investigated the morphological and functional effects of mycolactone in cultured human and rat dorsal root ganglia (DRG) neurons and the role of AT2R using EMA401. Primary sensory neurons were prepared from avulsed cervical human DRG and rat DRG; 24 h after plating, neurons were incubated for 24 to 96 h with synthetic mycolactone A/B, followed by immunostaining with antibodies to PGP9.5, Gap43, β tubulin, or Mitotracker dye staining. Acute functional effects were examined by measuring capsaicin responses with calcium imaging in DRG neuronal cultures treated with mycolactone. Results Morphological effects: Mycolactone-treated cultures showed dramatically reduced numbers of surviving neurons and non-neuronal cells, reduced Gap43 and β tubulin expression, degenerating neurites and reduced cell body diameter, compared with controls. Dose-related reduction of neurite length was observed in mycolactone-treated cultures. Mitochondria were distributed throughout the length of neurites and soma of control neurons, but clustered in the neurites and soma of mycolactone-treated neurons. Functional effects: Mycolactone-treated human and rat DRG neurons showed dose-related inhibition of capsaicin responses, which were reversed by calcineurin inhibitor cyclosporine and phosphodiesterase inhibitor 3-isobutyl-1-Methylxanthine, indicating involvement of cAMP/ATP reduction. The morphological and functional effects of mycolactone were not altered by Angiotensin II or AT2R antagonist EMA401. Conclusion Mycolactone

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

    PubMed Central

    Ma, Fei; Zhang, Liping; Westlund, Karin N

    2009-01-01

    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. PMID:19531269

  8. Microstimulation of the lumbar DRG recruits primary afferent neurons in localized regions of lower limb.

    PubMed

    Ayers, Christopher A; Fisher, Lee E; Gaunt, Robert A; Weber, Douglas J

    2016-07-01

    Patterned microstimulation of the dorsal root ganglion (DRG) has been proposed as a method for delivering tactile and proprioceptive feedback to amputees. Previous studies demonstrated that large- and medium-diameter afferent neurons could be recruited separately, even several months after implantation. However, those studies did not examine the anatomical localization of sensory fibers recruited by microstimulation in the DRG. Achieving precise recruitment with respect to both modality and receptive field locations will likely be crucial to create a viable sensory neuroprosthesis. In this study, penetrating microelectrode arrays were implanted in the L5, L6, and L7 DRG of four isoflurane-anesthetized cats instrumented with nerve cuff electrodes around the proximal and distal branches of the sciatic and femoral nerves. A binary search was used to find the recruitment threshold for evoking a response in each nerve cuff. The selectivity of DRG stimulation was characterized by the ability to recruit individual distal branches to the exclusion of all others at threshold; 84.7% (n = 201) of the stimulation electrodes recruited a single nerve branch, with 9 of the 15 instrumented nerves recruited selectively. The median stimulation threshold was 0.68 nC/phase, and the median dynamic range (increase in charge while stimulation remained selective) was 0.36 nC/phase. These results demonstrate the ability of DRG microstimulation to achieve selective recruitment of the major nerve branches of the hindlimb, suggesting that this approach could be used to drive sensory input from localized regions of the limb. This sensory input might be useful for restoring tactile and proprioceptive feedback to a lower-limb amputee. PMID:27052583

  9. Neurokinins inhibit low threshold inactivating K+ currents in capsaicin responsive DRG neurons

    PubMed Central

    Sculptoreanu, Adrian; Artim, Debra E.; de Groat, William C.

    2009-01-01

    Neurokinins (NK) released from terminals of dorsal root ganglion (DRG) neurons may control firing of these neurons by an autofeedback mechanism. In this study we used patch clamp recording techniques to determine if NKs alter excitability of rat L4-S3 DRG neurons by modulating K+ currents. In capsaicin (CAPS)-responsive phasic neurons substance P (SP) lowered action potential (AP) threshold and increased the number of APs elicited by depolarizing current pulses. SP and a selective NK2 agonist, [βAla8]-neurokinin A (4–10) also inhibited low threshold inactivating K+ currents isolated by blocking non-inactivating currents with a combination of high TEA, (−) verapamil and nifedipine. Currents recorded under these conditions were heteropodatoxin-sensitive (Kv4 blocker) and α-dendrotoxin insensitive (Kv1.1 and Kv1.2 blocker). SP and NKA elicited a >10 mV positive shift of the voltage dependence of activation of the low threshold currents. This effect was absent in CAPS-unresponsive neurons. The effect of SP or NKA on K+ currents in CAPS-responsive phasic neurons was fully reversed by an NK2 receptor antagonist (MEN10376) but only partially reversed by a PKC inhibitor (bisindolylmaleimide). An NK1 selective agonist ([Sar9, Met11]-substance P) or direct activation of PKC with phorbol 12,13-dibutyrate, did not change firing in CAPS-responsive neurons, but did inhibit various types of K+ currents that activated over a wide range of voltages. These data suggest that the excitability of CAPS-responsive phasic afferent neurons is increased by activation of NK2 receptors and that this is due in part to inhibition and a positive voltage shift in the activation of heteropodatoxin-sensitive Kv4 channels. PMID:19631644

  10. CX3CL1-mediated macrophage activation contributed to paclitaxel-induced DRG neuronal apoptosis and painful peripheral neuropathy.

    PubMed

    Huang, Zhen-Zhen; Li, Dai; Liu, Cui-Cui; Cui, Yu; Zhu, He-Quan; Zhang, Wen-Wen; Li, Yong-Yong; Xin, Wen-Jun

    2014-08-01

    Painful peripheral neuropathy is a dose-limiting side effect of paclitaxel therapy, which hampers the optimal clinical management of chemotherapy in cancer patients. Currently the underlying mechanisms remain largely unknown. Here we showed that the clinically relevant dose of paclitaxel (3×8mg/kg, cumulative dose 24mg/kg) induced significant upregulation of the chemokine CX3CL1 in the A-fiber primary sensory neurons in vivo and in vitro and infiltration of macrophages into the dorsal root ganglion (DRG) in rats. Paclitaxel treatment also increased cleaved caspase-3 expression, induced the loss of primary afferent terminal fibers and decreased sciatic-evoked A-fiber responses in the spinal dorsal horn, indicating DRG neuronal apoptosis induced by paclitaxel. In addition, the paclitaxel-induced DRG neuronal apoptosis occurred exclusively in the presence of macrophage in vitro study. Intrathecal or systemic injection of CX3CL1 neutralizing antibody blocked paclitaxel-induced macrophage recruitment and neuronal apoptosis in the DRG, and also attenuated paclitaxel-induced allodynia. Furthermore, depletion of macrophage by systemic administration of clodronate inhibited paclitaxel-induced allodynia. Blocking CX3CL1 decreased activation of p38 MAPK in the macrophage, and inhibition of p38 MAPK activity blocked the neuronal apoptosis and development of mechanical allodynia induced by paclitaxel. These findings provide novel evidence that CX3CL1-recruited macrophage contributed to paclitaxel-induced DRG neuronal apoptosis and painful peripheral neuropathy. PMID:24681252

  11. Activity-dependent hyperpolarization of EGABA is absent in cutaneous DRG neurons from inflamed rats

    PubMed Central

    Zhu, Yi; Zhang, Xiu-Lin; Gold, Michael S.

    2013-01-01

    A shift in GABAA signaling from inhibition to excitation in primary afferent neurons appears to contribute to the inflammation-induced increase in afferent input to the central nervous system (CNS). An activity-dependent depolarization of the GABA equilibrium potential (EGABA) has been described in CNS neurons which drives a shift in GABAA signaling from inhibition to excitation. The purpose of the present study was to determine if such an activity-dependent depolarization of EGABA occurs in primary afferents and whether the depolarization is amplified with persistent inflammation. Acutely dissociated retrogradely labeled cutaneous DRG neurons from naïve and inflamed rats were studied with gramicidin perforated patch recording. Rather than a depolarization, 200 action potentials delivered at 2 Hz resulted in a ~10 mV hyperpolarization of EGABA in cutaneous neurons from naïve rats. No such hyperpolarization was observed in neurons from inflamed rats. The shift in EGABA was not blocked by 10 µM bumetanide. Furthermore, because activity-dependent hyperpolarization of EGABA was fully manifest in the absence of HCO3− in the bath solution, this shift was not dependent on a change in HCO3−-Cl− exchanger activity, despite evidence of HCO3−-Cl− exchangers in DRG neurons that may contribute to the establishment of EGABA in the presence of HCO3−. While the mechanism underlying the activity-dependent hyperpolarization of EGABA has yet to be identified, because this mechanism appears to function as a form of feedback inhibition, facilitating GABA mediated inhibition of afferent activity, it may serve as a novel target for the treatment of inflammatory pain. PMID:24135545

  12. Single-cell RNA-seq reveals distinct injury responses in different types of DRG sensory neurons

    PubMed Central

    Hu, Ganlu; Huang, Kevin; Hu, Youjin; Du, Guizhen; Xue, Zhigang; Zhu, Xianmin; Fan, Guoping

    2016-01-01

    Peripheral nerve injury leads to various injury-induced responses in sensory neurons including physiological pain, neuronal cell death, and nerve regeneration. In this study, we performed single-cell RNA-sequencing (scRNA-seq) analysis of mouse nonpeptidergic nociceptors (NP), peptidergic nociceptors (PEP), and large myelinated sensory neurons (LM) under both control and injury conditions at 3 days after sciatic nerve transection (SNT). After performing principle component and weighted gene co-expression network analysis, we categorized dorsal root ganglion (DRG) neurons into different subtypes and discovered co-regulated injury-response genes including novel regeneration associated genes (RAGs) in association with neuronal development, protein translation and cytoplasm transportation. In addition, we found significant up-regulation of the genes associated with cell death such as Pdcd2 in a subset of NP neurons after axotomy, implicating their actions in neuronal cell death upon nerve injury. Our study revealed the distinctive and sustained heterogeneity of transcriptomic responses to injury at single neuron level, implicating the involvement of different gene regulatory networks in nerve regeneration, neuronal cell death and neuropathy in different population of DRG neurons. PMID:27558660

  13. Single-cell RNA-seq reveals distinct injury responses in different types of DRG sensory neurons.

    PubMed

    Hu, Ganlu; Huang, Kevin; Hu, Youjin; Du, Guizhen; Xue, Zhigang; Zhu, Xianmin; Fan, Guoping

    2016-01-01

    Peripheral nerve injury leads to various injury-induced responses in sensory neurons including physiological pain, neuronal cell death, and nerve regeneration. In this study, we performed single-cell RNA-sequencing (scRNA-seq) analysis of mouse nonpeptidergic nociceptors (NP), peptidergic nociceptors (PEP), and large myelinated sensory neurons (LM) under both control and injury conditions at 3 days after sciatic nerve transection (SNT). After performing principle component and weighted gene co-expression network analysis, we categorized dorsal root ganglion (DRG) neurons into different subtypes and discovered co-regulated injury-response genes including novel regeneration associated genes (RAGs) in association with neuronal development, protein translation and cytoplasm transportation. In addition, we found significant up-regulation of the genes associated with cell death such as Pdcd2 in a subset of NP neurons after axotomy, implicating their actions in neuronal cell death upon nerve injury. Our study revealed the distinctive and sustained heterogeneity of transcriptomic responses to injury at single neuron level, implicating the involvement of different gene regulatory networks in nerve regeneration, neuronal cell death and neuropathy in different population of DRG neurons. PMID:27558660

  14. Role of laser fluence in protein synthesis of cultured DRG neurons following low-level laser irradiation

    NASA Astrophysics Data System (ADS)

    Zheng, Liqin; Qiu, Caimin; Wang, Yuhua; Zeng, Yixiu; Yang, Hongqin; Zhang, Yanding; Xie, Shusen

    2014-11-01

    Low-level lasers have been used to relieve pain in clinical for many years. But the mechanism is not fully clear. In animal models, nitric oxide (NO) has been reported involving in the transmission and modulation of nociceptive signals. So the objective of this study was to establish whether low-level laser with different fluence could stimulate the production of nitric oxide synthese (NOS), which produces NO in cultured primary dorsal root ganglion neurons (DRG neurons). The primary DRG neurons were isolated from healthy Sprague Dawley rats (8-12 weeks of age) and spread on 35 mm culture dishes specially used for confocal microscopy. 24 hours after spreading, cells were irradiated with 658 nm laser for two consecutive days at the energy density of 20, 40, 60 and 80 mJ·cm-2 respectively. Control groups were not exposed to the laser, but were kept under the same conditions as the irradiated ones. The synthesis of NOS after laser irradiation was detected by immunofluorescence assay, and the changes of NOS were evaluated using confocal microscopy and Image J software. The results showed that all the laser fluence could promote the production of NOS in DRG neurons, especially the 60 mJ·cm-2 . These results demonstrated that low-level laser irradiation could modify protein synthesis in a dose- or fluence- dependent manner, and indicated that low-level laser irradiation might achieve the analgesic effect through modulation of NO production.

  15. Intraganglionic interactions between satellite cells and adult sensory neurons.

    PubMed

    Christie, Kimberly; Koshy, Dilip; Cheng, Chu; Guo, GuiFang; Martinez, Jose A; Duraikannu, Arul; Zochodne, Douglas W

    2015-07-01

    Perineuronal satellite cells have an intimate anatomical relationship with sensory neurons that suggests close functional collaboration and mutual support. We examined several facets of this relationship in adult sensory dorsal root ganglia (DRG). Collaboration included the support of process outgrowth by clustering of satellite cells, induction of distal branching behavior by soma signaling, the capacity of satellite cells to respond to distal axon injury of its neighboring neurons, and evidence of direct neuron-satellite cell exchange. In vitro, closely adherent coharvested satellite cells routinely clustered around new outgrowing processes and groups of satellite cells attracted neurite processes. Similar clustering was encountered in the pseudounipolar processes of intact sensory neurons within intact DRG in vivo. While short term exposure of distal growth cones of unselected adult sensory neurons to transient gradients of a PTEN inhibitor had negligible impacts on their behavior, exposure of the soma induced early and substantial growth of their distant neurites and branches, an example of local soma signaling. In turn, satellite cells sensed when distal neuronal axons were injured by enlarging and proliferating. We also observed that satellite cells were capable of internalizing and expressing a neuron fluorochrome label, diamidino yellow, applied remotely to distal injured axons of the neuron and retrogradely transported to dorsal root ganglia sensory neurons. The findings illustrate a robust interaction between intranganglionic neurons and glial cells that involve two way signals, features that may be critical for both regenerative responses and ongoing maintenance. PMID:25979201

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

    PubMed Central

    Momeni, Hamid Reza; Soleimani Mehranjani, Malek; Shariatzadeh, Mohammad Ali; Haddadi, Mahnaz

    2013-01-01

    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. PMID:24027661

  17. Differential upregulation in DRG neurons of an α2δ-1 splice variant with a lower affinity for gabapentin after peripheral sensory nerve injury

    PubMed Central

    Lana, Beatrice; Schlick, Bettina; Martin, Stuart; Pratt, Wendy S.; Page, Karen M.; Goncalves, Leonor; Rahman, Wahida; Dickenson, Anthony H.; Bauer, Claudia S.; Dolphin, Annette C.

    2014-01-01

    The α2δ-1 protein is an auxiliary subunit of voltage-gated calcium channels, critical for neurotransmitter release. It is upregulated in dorsal root ganglion (DRG) neurons following sensory nerve injury, and is also the therapeutic target of the gabapentinoid drugs, which are efficacious in both experimental and human neuropathic pain conditions. α2δ-1 has 3 spliced regions: A, B, and C. A and C are cassette exons, whereas B is introduced via an alternative 3′ splice acceptor site. Here we have examined the presence of α2δ-1 splice variants in DRG neurons, and have found that although the main α2δ-1 splice variant in DRG is the same as that in brain (α2δ-1 ΔA+B+C), there is also another α2δ-1 splice variant (ΔA+BΔC), which is expressed in DRG neurons and is differentially upregulated compared to the main DRG splice variant α2δ-1 ΔA+B+C following spinal nerve ligation. Furthermore, this differential upregulation occurs preferentially in a small nonmyelinated DRG neuron fraction, obtained by density gradient separation. The α2δ-1 ΔA+BΔC splice variant supports CaV2 calcium currents with unaltered properties compared to α2δ-1 ΔA+B+C, but shows a significantly reduced affinity for gabapentin. This variant could therefore play a role in determining the efficacy of gabapentin in neuropathic pain. PMID:24315988

  18. Distinct subclassification of DRG neurons innervating the distal colon and glans penis/distal urethra based on the electrophysiological current signature

    PubMed Central

    Petruska, Jeffrey C.; Cooper, Brian Y.; Johnson, Richard D.

    2014-01-01

    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. PMID:24872531

  19. Role of oxidative stress in rabies virus infection of adult mouse dorsal root ganglion neurons.

    PubMed

    Jackson, Alan C; Kammouni, Wafa; Zherebitskaya, Elena; Fernyhough, Paul

    2010-05-01

    Rabies virus infection of dorsal root ganglia (DRG) was studied in vitro with cultured adult mouse DRG neurons. Recent in vivo studies of transgenic mice that express the yellow fluorescent protein indicate that neuronal process degeneration, involving both dendrites and axons, occurs in mice infected with the challenge virus standard (CVS) strain of rabies virus by footpad inoculation. Because of the similarities of the morphological changes in experimental rabies and in diabetic neuropathy and other diseases, we hypothesize that neuronal process degeneration occurs as a result of oxidative stress. DRG neurons were cultured from adult ICR mice. Two days after plating, they were infected with CVS. Immunostaining was evaluated with CVS- and mock-infected cultures for neuron specific beta-tubulin, rabies virus antigen, and amino acid adducts of 4-hydroxy-2-nonenal (4-HNE) (marker of lipid peroxidation and hence oxidative stress). Neuronal viability (by trypan blue exclusion), terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining, and axonal growth were also assessed with the cultures. CVS infected 33 to 54% of cultured DRG neurons. Levels of neuronal viability and TUNEL staining were similar in CVS- and mock-infected DRG neurons. There were significantly more 4-HNE-labeled puncta at 2 and 3 days postinfection in CVS-infected cultures than in mock-infected cultures, and axonal outgrowth was reduced at these time points in CVS infection. Axonal swellings with 4-HNE-labeled puncta were also associated with aggregations of actively respiring mitochondria. We have found evidence that rabies virus infection in vitro causes axonal injury of DRG neurons through oxidative stress. Oxidative stress may be important in vivo in rabies and may explain previous observations of the degeneration of neuronal processes. PMID:20181692

  20. Neurotoxicity to DRG neurons varies between rodent strains treated with cisplatin and bortezomib.

    PubMed

    Podratz, Jewel L; Kulkarni, Amit; Pleticha, Josef; Kanwar, Rahul; Beutler, Andreas S; Staff, Nathan P; Windebank, Anthony J

    2016-03-15

    Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose limiting side effect that can lead to long-term morbidity. Approximately one-third of patients receiving chemotherapy with taxanes, vinca alkaloids, platinum compounds or proteasome inhibitors develop this toxic side effect. It is not possible to predict who will get CIPN, however, genetic susceptibility may play a role. We explored this hypothesis using an established in vitro dorsal root ganglia neurite outgrowth (DRG-NOG) assay to assess possible genetic influences for cisplatin- and bortezomib-induced neurotoxicity. Almost all previous in vitro studies have used rats or mice. We compared DRG-NOG between four genetically defined, inbred mouse strains (C57BL/6J, DBA/2J, BALB/cJ, and C3H/HeJ) and one rat strain (Sprague Dawley). Our studies found differences in cisplatin and bortezomib-induced neurotoxicity between mouse and rat strains and between the different mouse strains. C57BL/6J and Balb/cJ DRG-NOG was more sensitive to cisplatin than DBA/2J and C3H/HeJ DRG-NOG, and all mouse strains were more sensitive to cisplatin than rat. Bortezomib induced a biphasic dose response in DBA/2J and C3H/H3J mice. C57BL/6J DRG-NOG was most sensitive and Balb/cJ DRG-NOG was least sensitive to bortezomib. Our animal data supports the hypothesis that genetic background may play a role in CIPN and care must be taken when rodent models are used to better understand the contribution of genetics in patient susceptibility to CIPN. PMID:26944133

  1. 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

    PubMed Central

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

    2015-01-01

    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. PMID:26101670

  2. Increase of transcription factor EB (TFEB) and lysosomes in rat DRG neurons and their transportation to the central nerve terminal in dorsal horn after nerve injury.

    PubMed

    Jung, J; Uesugi, N; Jeong, N Y; Park, B S; Konishi, H; Kiyama, H

    2016-01-28

    In the spinal dorsal horn (DH), nerve injury activates microglia and induces neuropathic pain. Several studies clarified an involvement of adenosine triphosphate (ATP) in the microglial activation. However, the origin of ATP together with the release mechanism is unclear. Recent in vitro study revealed that an ATP marker, quinacrine, in lysosomes was released from neurite terminal of dorsal root ganglion (DRG) neurons to extracellular space via lysosomal exocytosis. Here, we demonstrate a possibility that the lysosomal ingredient including ATP released from DRG neurons by lysosomal-exocytosis is an additional source of the glial activation in DH after nerve injury. After rat L5 spinal nerve ligation (SNL), mRNA for transcription factor EB (TFEB), a transcription factor controlling lysosomal activation and exocytosis, was induced in the DRG. Simultaneously both lysosomal protein, LAMP1- and vesicular nuclear transporter (VNUT)-positive vesicles were increased in L5 DRG neurons and ipsilateral DH. The quinacrine staining in DH was increased and co-localized with LAMP1 immunoreactivity after nerve injury. In DH, LAMP1-positive vesicles were also co-localized with a peripheral nerve marker, Isolectin B4 (IB4) lectin. Injection of the adenovirus encoding mCherry-LAMP1 into DRG showed that mCherry-positive lysosomes are transported to the central nerve terminal in DH. These findings suggest that activation of lysosome synthesis including ATP packaging in DRG, the central transportation of the lysosome, and subsequent its exocytosis from the central nerve terminal of DRG neurons in response to nerve injury could be a partial mechanism for activation of microglia in DH. This lysosome-mediated microglia activation mechanism may provide another clue to control nociception and pain. PMID:26601776

  3. Upregulation of Ih expressed in IB4-negative Aδ nociceptive DRG neurons contributes to mechanical hypersensitivity associated with cervical radiculopathic pain

    PubMed Central

    Liu, Da-Lu; Lu, Na; Han, Wen-Juan; Chen, Rong-Gui; Cong, Rui; Xie, Rou-Gang; Zhang, Yu-Fei; Kong, Wei-Wei; Hu, San-Jue; Luo, Ceng

    2015-01-01

    Cervical radiculopathy represents aberrant mechanical hypersensitivity. Primary sensory neuron’s ability to sense mechanical force forms mechanotransduction. However, whether this property undergoes activity-dependent plastic changes and underlies mechanical hypersensitivity associated with cervical radiculopathic pain (CRP) is not clear. Here we show a new CRP model producing stable mechanical compression of dorsal root ganglion (DRG), which induces dramatic behavioral mechanical hypersensitivity. Amongst nociceptive DRG neurons, a mechanically sensitive neuron, isolectin B4 negative Aδ-type (IB4− Aδ) DRG neuron displays spontaneous activity with hyperexcitability after chronic compression of cervical DRGs. Focal mechanical stimulation on somata of IB4- Aδ neuron induces abnormal hypersensitivity. Upregulated HCN1 and HCN3 channels and increased Ih current on this subset of primary nociceptors underlies the spontaneous activity together with neuronal mechanical hypersensitivity, which further contributes to the behavioral mechanical hypersensitivity associated with CRP. This study sheds new light on the functional plasticity of a specific subset of nociceptive DRG neurons to mechanical stimulation and reveals a novel mechanism that could underlie the mechanical hypersensitivity associated with cervical radiculopathy. PMID:26577374

  4. Slit1 promotes regenerative neurite outgrowth of adult dorsal root ganglion neurons in vitro via binding to the Robo receptor.

    PubMed

    Zhang, Hai Ying; Zheng, Lin Feng; Yi, Xi Nan; Chen, Zhi Bin; He, Zhong Ping; Zhao, Dan; Zhang, Xian Fang; Ma, Zhi Jian

    2010-07-01

    Secreted Slit proteins have previously been shown to signal through Roundabout (Robo) receptors to negatively regulate axon guidance and cell migration. During vertebrate development, Slit proteins have also been shown to stimulate branching and elongation of sensory axons and cortical dendrites. In this study, Slit1/Robo2 mRNA and protein expressions were detected in adult rat dorsal root ganglion (DRG) and in cultured DRG neurons. Treatment of both models with recombinant, soluble Slit1 protein was found to promote neurite outgrowth and elongation. In contrast, treatment with a recombinant human Robo2/Fc chimera inhibited neurite outgrowth and elongation. When adult DRG and cultured DRG neurons were pretreated with soluble recombinant human Robo2/Fc chimera, neurite outgrowth and elongation was not induced. These findings indicate that Slit1/Robo2 signaling may have a role in regulating peripheral nerve regeneration. PMID:20172023

  5. Adult DRG Stem/Progenitor Cells Generate Pericytes in the Presence of Central Nervous System (CNS) Developmental Cues, and Schwann Cells in Response to CNS Demyelination.

    PubMed

    Vidal, Marie; Maniglier, Madlyne; Deboux, Cyrille; Bachelin, Corinne; Zujovic, Violetta; Baron-Van Evercooren, Anne

    2015-06-01

    It has been proposed that the adult dorsal root ganglia (DRG) harbor neural stem/progenitor cells (NPCs) derived from the neural crest. However, the thorough characterization of their stemness and differentiation plasticity was not addressed. In this study, we investigated adult DRG-NPC stem cell properties overtime, and their fate when ectopically grafted in the central nervous system. We compared them in vitro and in vivo to the well-characterized adult spinal cord-NPCs derived from the same donors. Using micro-dissection and neurosphere cultures, we demonstrate that adult DRG-NPCs have quasi unlimited self-expansion capacities without compromising their tissue specific molecular signature. Moreover, they differentiate into multiple peripheral lineages in vitro. After transplantation, adult DRG-NPCs generate pericytes in the developing forebrain but remyelinating Schwann cells in response to spinal cord demyelination. In addition, we show that axonal and endothelial/astrocytic factors as well astrocytes regulate the fate of adult DRG-NPCs in culture. Although the adult DRG-NPC multipotency is restricted to the neural crest lineage, their dual responsiveness to developmental and lesion cues highlights their impressive adaptive and repair potentials making them valuable targets for regenerative medicine. PMID:25786382

  6. Electrophysiological characteristics of IB4-negative TRPV1-expressing muscle afferent DRG neurons

    PubMed Central

    Lin, Yi-Wen; Chen, Chih-Cheng

    2015-01-01

    Muscle afferent neurons that express transient receptor potential vanilloid type I (TRPV1) are responsible for muscle pain associated with tissue acidosis. We have previously found that TRPV1 of isolectin B4 (IB4)-negative muscle nociceptors plays an important role in the acid-induced hyperalgesic priming and the development of chronic hyperalgesia in a mouse model of fibromyalgia. To understand the electrophysiological properties of the TRPV1-expressing muscle afferent neurons, we used whole-cell patch clamp recording to study the acid responsiveness and action potential (AP) configuration of capsaicin-sensitive neurons innervating to gastrocnemius muscle. Here we showed that IB4-negative TRPV1-expressing muscle afferent neurons are heterogeneous in terms of cell size, resting membrane potential, AP configuration, tetrodotoxin (TTX)-resistance, and acid-induced current (Iacid), as well as capsaicin-induced current (Icap). TRPV1-expressing neurons were all acid-sensitive and could be divided into two acid-sensitive groups depending on an acid-induced sustained current (type I) or an acid-induced biphasic ASIC3-like current (type II). Type I TRPV1-expressing neurons were distinguishable from type II TRPV1-expressing neurons in AP overshoot, after-hyperpolarization duration, and all Iacid parameters, but not in AP threshold, TTX-resistance, resting membrane potential, and Icap parameters. These differential biophysical properties of TRPV1-expressing neurons might partially annotate their different roles involved in the development and maintenance of chronic muscle pain. PMID:27493509

  7. Knockout of Slo2.2 enhances itch, abolishes KNa current, and increases action potential firing frequency in DRG neurons

    PubMed Central

    Martinez-Espinosa, Pedro L; Wu, Jianping; Yang, Chengtao; Gonzalez-Perez, Vivian; Zhou, Huifang; Liang, Hongwu; Xia, Xiao-Ming; Lingle, Christopher J

    2015-01-01

    Two mammalian genes, Kcnt1 and Kcnt2, encode pore-forming subunits of Na+-dependent K+ (KNa) channels. Progress in understanding KNa channels has been hampered by the absence of specific tools and methods for rigorous KNa identification in native cells. Here, we report the genetic disruption of both Kcnt1 and Kcnt2, confirm the loss of Slo2.2 and Slo2.1 protein, respectively, in KO animals, and define tissues enriched in Slo2 expression. Noting the prevalence of Slo2.2 in dorsal root ganglion, we find that KO of Slo2.2, but not Slo2.1, results in enhanced itch and pain responses. In dissociated small diameter DRG neurons, KO of Slo2.2, but not Slo2.1, abolishes KNa current. Utilizing isolectin B4+ neurons, the absence of KNa current results in an increase in action potential (AP) firing and a decrease in AP threshold. Activation of KNa acts as a brake to initiation of the first depolarization-elicited AP with no discernible effect on afterhyperpolarizations. DOI: http://dx.doi.org/10.7554/eLife.10013.001 PMID:26559620

  8. Spatiotemporal Localization of Injury Potentials in DRG Neurons During Vincristine-Induced Axonal Degeneration

    PubMed Central

    Ravula, Surendra K.; Wang, Min S; McClain, Maxine A; Asress, Seneshaw A; Frazier, Bruno; Glass, Jonathan D

    2007-01-01

    The distal to proximal degeneration of axons, or “dying back” is a common pattern of neuropathology in many diseases of the PNS and CNS. A long-standing debate has centered on whether this pattern of neurodegeneration is due to an insult to the cell body or to the axon itself, although it is likely that mechanisms are different for specific disease entities. We have addressed this question in a model system of vincristine-induced axonal degeneration. Here, we created a novel experimental apparatus combining a microfluidic divider with a multielectrode array substrate to allow for independent monitoring of injury-induced electrical activity from dorsal root ganglion (DRG) cell bodies and axons while isolating them into their own culture microenvironments. At specified doses, exposure of the cell body to vincristine caused neither morphological neurodegeneration nor persistent hyperexcitablility. In comparison, exposure of the distal axon to the same dose of vincristine first caused a decrease in the excitability of the axon and then axonal degeneration in a dying back pattern. Additionally, exposure of axons to vincristine caused an initial period of hyperexcitability in the cell bodies, suggesting that a signal is transmitted from the distal axon to the soma during the progression of vincristine-induced axonal degeneration. These data support the proposition that vincristine has a direct neurotoxic effect on the axon. PMID:17267126

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

    PubMed Central

    2012-01-01

    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. PMID:23134641

  10. The Role of Rac1 in the Growth Cone Dynamics and Force Generation of DRG Neurons

    PubMed Central

    Sayyad, Wasim A.; Fabris, Paolo; Torre, Vincent

    2016-01-01

    We used optical tweezers, video imaging, immunocytochemistry and a variety of inhibitors to analyze the role of Rac1 in the motility and force generation of lamellipodia and filopodia from developing growth cones of isolated Dorsal Root Ganglia neurons. When the activity of Rac1 was inhibited by the drug EHop-016, the period of lamellipodia protrusion/retraction cycles increased and the lamellipodia retrograde flow rate decreased; moreover, the axial force exerted by lamellipodia was reduced dramatically. Inhibition of Arp2/3 by a moderate amount of the drug CK-548 caused a transient retraction of lamellipodia followed by a complete recovery of their usual motility. This recovery was abolished by the concomitant inhibition of Rac1. The filopodia length increased upon inhibition of both Rac1 and Arp2/3, but the speed of filopodia protrusion increased when Rac1 was inhibited and decreased instead when Arp2/3 was inhibited. These results suggest that Rac1 acts as a switch that activates upon inhibition of Arp2/3. Rac1 also controls the filopodia dynamics necessary to explore the environment. PMID:26766136

  11. The expression of ELK transcription factors in adult DRG: Novel isoforms, antisense transcripts and upregulation by nerve damage.

    PubMed

    Kerr, Niall; Pintzas, Alexander; Holmes, Fiona; Hobson, Sally-Ann; Pope, Robert; Wallace, Mark; Wasylyk, Christine; Wasylyk, Bohdan; Wynick, David

    2010-06-01

    ELK transcription factors are known to be expressed in a number of regions in the nervous system. We show by RT-PCR that the previously described Elk1, Elk3/Elk3b/Elk3c and Elk4 mRNAs are expressed in adult dorsal root ganglia (DRG), together with the novel alternatively spliced isoforms Elk1b, Elk3d and Elk4c/Elk4d/Elk4e. These isoforms are also expressed in brain, heart, kidney and testis. In contrast to Elk3 protein, the novel Elk3d isoform is cytoplasmic, fails to bind ETS binding sites and yet can activate transcription by an indirect mechanism. The Elk3 and Elk4 genes are overlapped by co-expressed Pctk2 (Cdk17) and Mfsd4 genes, respectively, with the potential formation of Elk3/Pctaire2 and Elk4/Mfsd4 sense-antisense mRNA heteroduplexes. After peripheral nerve injury the Elk3 mRNA isoforms are each upregulated approximately 2.3-fold in DRG (P<0.005), whereas the natural antisense Pctaire2 isoforms show only a small increase (21%, P<0.01) and Elk1 and Elk4 mRNAs are unchanged. PMID:20304071

  12. DiI-Labeling of DRG Neurons to Study Axonal Branching in a Whole Mount Preparation of Mouse Embryonic Spinal Cord

    PubMed Central

    Schmidt, Hannes; Rathjen, Fritz G.

    2011-01-01

    Here we present a technique to label the trajectories of small groups of DRG neurons into the embryonic spinal cord by diffusive staining using the lipophilic tracer 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)1. The comparison of axonal pathways of wild-type with those of mouse lines in which genes are mutated allows testing for a functional role of candidate proteins in the control of axonal branching which is an essential mechanism in the wiring of the nervous system. Axonal branching enables an individual neuron to connect with multiple targets, thereby providing the physical basis for the parallel processing of information. Ramifications at intermediate target regions of axonal growth may be distinguished from terminal arborization. Furthermore, different modes of axonal branch formation may be classified depending on whether branching results from the activities of the growth cone (splitting or delayed branching) or from the budding of collaterals from the axon shaft in a process called interstitial branching2 (Fig. 1). The central projections of neurons from the DRG offer a useful experimental system to study both types of axonal branching: when their afferent axons reach the dorsal root entry zone (DREZ) of the spinal cord between embryonic days 10 to 13 (E10 - E13) they display a stereotyped pattern of T- or Y-shaped bifurcation. The two resulting daughter axons then proceed in rostral or caudal directions, respectively, at the dorsolateral margin of the cord and only after a waiting period collaterals sprout from these stem axons to penetrate the gray matter (interstitial branching) and project to relay neurons in specific laminae of the spinal cord where they further arborize (terminal branching)3. DiI tracings have revealed growth cones at the dorsal root entry zone of the spinal cord that appeared to be in the process of splitting suggesting that bifurcation is caused by splitting of the growth cone itself4 (Fig. 2), however

  13. Modulation of Extracellular ATP Content of Mast Cells and DRG Neurons by Irradiation: Studies on Underlying Mechanism of Low-Level-Laser Therapy

    PubMed Central

    Hu, Lei; Grygorczyk, Ryszard; Shen, Xueyong; Schwarz, Wolfgang

    2015-01-01

    Low-level-laser therapy (LLLT) is an effective complementary treatment, especially for anti-inflammation and wound healing in which dermis or mucus mast cells (MCs) are involved. In periphery, MCs crosstalk with neurons via purinergic signals and participate in various physiological and pathophysiological processes. Whether extracellular ATP, an important purine in purinergic signaling, of MCs and neurons could be modulated by irradiation remains unknown. In this study, effects of red-laser irradiation on extracellular ATP content of MCs and dorsal root ganglia (DRG) neurons were investigated and underlying mechanisms were explored in vitro. Our results show that irradiation led to elevation of extracellular ATP level in the human mast cell line HMC-1 in a dose-dependent manner, which was accompanied by elevation of intracellular ATP content, an indicator for ATP synthesis, together with [Ca2+]i elevation, a trigger signal for exocytotic ATP release. In contrast to MCs, irradiation attenuated the extracellular ATP content of neurons, which could be abolished by ARL 67156, a nonspecific ecto-ATPases inhibitor. Our results suggest that irradiation potentiates extracellular ATP of MCs by promoting ATP synthesis and release and attenuates extracellular ATP of neurons by upregulating ecto-ATPase activity. The opposite responses of these two cell types indicate complex mechanisms underlying LLLT. PMID:25691809

  14. Neuron-enriched cultures of adult rat dorsal root ganglia: establishment, characterization, survival, and neuropeptide expression in response to trophic factors.

    PubMed

    Grothe, C; Unsicker, K

    1987-01-01

    It is unknown whether adult dorsal root ganglion (DRG) neurons require trophic factors for their survival and maintenance of neuropeptide phenotypes. We have established and characterized neuron-enriched cultures of adult rat DRGs and investigated their responses to nerve growth factor (NGF), ciliary neuronotrophic factor (CNTF), pig brain extract (PBE, crude fraction of brain-derived neuronotrophic factor, BDNF), and laminin (LN). DRGs were dissected from levels C1 through L6 and dissociated and freed from myelin fragments and most satellite (S-100-immunoreactive) cells by centrifugation on Percoll and preplating. The enriched neurons, characterized by their morphology and immunoreactivity for neuron-specific enolase, constituted a population representative of the in vivo situation with regard to expression of substance P (SP), somatostatin (SOM), and cholecystokinin-8 (CCK) immunoreactivities. In the absence of trophic factors and using polyornithine (PORN) as a substratum, 60-70% of the neurons present initially (0.5 days) had died after 7 days. LN as a substratum did not prevent a 30% loss of neurons up to day 4.5, but it subsequently maintained DRG neurons at a plateau. This behavior might reflect a cotrophic effect of LN and factors provided by non-neuronal cells, whose proliferation between 4.5 and 7 days could not be prevented by addition of mitotic inhibitors of gamma-irradiation. CNTF, but not NGF, slightly enhanced survival at 7 days on either PORN or LN. No neuronal losses were found in non-enriched cultures or when enriched neurons were supplemented with PBE, indicating that non-neuronal cells and PBE provide factor(s) essential for adult DRG neuron survival. Proportions of SP-, SOM-, and CCK-immunoreactive cells were unaltered under any experimental condition, with the exception of a numerical decline in SP cells in 7-day cultures with LN, but not PORN, as the substratum. Our data, considered in the context of recent in vivo and vitro studies, suggest

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

    PubMed

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

    2013-01-01

    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. PMID:24147119

  16. Differential regulation of immune responses and macrophage/neuron interactions in the dorsal root ganglion in young and adult rats following nerve injury

    PubMed Central

    2009-01-01

    Background Neuropathic pain is an apparently spontaneous experience triggered by abnormal physiology of the peripheral or central nervous system, which evolves with time. Neuropathic pain arising from peripheral nerve injury is characterized by a combination of spontaneous pain, hyperalgesia and allodynia. There is no evidence of this type of pain in human infants or rat pups; brachial plexus avulsion, which causes intense neuropathic pain in adults, is not painful when the injury is sustained at birth. Since infants are capable of nociception from before birth and display both acute and chronic inflammatory pain behaviour from an early neonatal age, it appears that the mechanisms underlying neuropathic pain are differentially regulated over a prolonged postnatal period. Results We have performed a microarray analysis of the rat L4/L5 dorsal root ganglia (DRG), 7 days post spared nerve injury, a model of neuropathic pain. Genes that are regulated in adult rats displaying neuropathic behaviour were compared to those regulated in young rats (10 days old) that did not show the same neuropathic behaviour. The results show a set of genes, differentially regulated in the adult DRG, that are principally involved in immune system modulation. A functional consequence of this different immune response to injury is that resident macrophages cluster around the large A sensory neuron bodies in the adult DRG seven days post injury, whereas the macrophages in young DRG remain scattered evenly throughout the ganglion, as in controls. Conclusions The results show, for the first time, a major difference in the neuroimmune response to nerve injury in the dorsal root ganglion of young and adult rats. Differential analysis reveals a new set of immune related genes in the ganglia, that are differentially regulated in adult neuropathic pain, and that are consistent with the selective activation of macrophages around adult, but not young large A sensory neurons post injury. These

  17. Human sensory neurons: Membrane properties and sensitization by inflammatory mediators

    PubMed Central

    Zhang, Jingming; Page, Guy; Ghetti, Andrea; Gereau, Robert W.

    2014-01-01

    Biological differences in sensory processing between human and model organisms may present significant obstacles to translational approaches in treating chronic pain. To better understand the physiology of human sensory neurons, we performed whole-cell patch-clamp recordings from 141 human dorsal root ganglion (hDRG) neurons from five young adult donors without chronic pain. Nearly all small diameter hDRG neurons (<50 μm) displayed an inflection on the descending slope of the action potential, a defining feature of rodent nociceptive neurons. A high proportion of hDRG neurons were responsive to the algogens allyl isothiocyanate (AITC) and ATP, as well as the pruritogens histamine and chloroquine. We show that a subset of hDRG neurons responded to the inflammatory compounds bradykinin and prostaglandin E2 with action potential discharge and show evidence of sensitization including lower rheobase. Compared to electrically-evoked action potentials, chemically-induced action potentials were triggered from less depolarized thresholds and showed distinct after-hyperpolarization kinetics. These data indicate that most small/medium hDRG neurons can be classified as nociceptors, that they respond directly to compounds that produce pain and itch, and can be activated and sensitized by inflammatory mediators. The use of hDRG neurons as preclinical vehicles for target validation is discussed. PMID:24973718

  18. Role of nuclear factor-κB in oxidative stress associated with rabies virus infection of adult rat dorsal root ganglion neurons.

    PubMed

    Kammouni, Wafa; Hasan, Leena; Saleh, Ali; Wood, Heidi; Fernyhough, Paul; Jackson, Alan C

    2012-08-01

    Recent studies in an experimental model of rabies showed major structural changes in the brain involving neuronal processes that are associated with severe clinical disease. Cultured adult rat dorsal root ganglion (DRG) neurons infected with the challenge virus standard-11 strain of rabies virus (CVS) showed axonal swellings and immunostaining for 4-hydroxy-2-nonenal (4-HNE), indicating evidence of lipid peroxidation associated with oxidative stress and reduced axonal growth compared to that of mock-infected DRG neurons. We have evaluated whether nuclear factor (NF)-κB might act as a critical bridge linking CVS infection and oxidative stress. On Western immunoblotting, CVS infection induced expression of the NF-κB p50 subunit compared to that of mock infection. Ciliary neurotrophic factor, a potent activator of NF-κB, had no effect on mock-infected rat DRG neurons and reduced the number of 4-HNE-labeled puncta. SN50, a peptide inhibitor of NF-κB, and CVS infection had an additive effect in producing axonal swellings, indicating that NF-κB is neuroprotective. The fluorescent signal for subunit p50 was quantitatively evaluated in the nucleus and cytoplasm of mock- and CVS-infected rat DRG neurons. At 24 h postinfection (p.i.), there was a significant increase in the nucleus/cytoplasm ratio, indicating increased transcriptional activity of NF-κB, perhaps as a response to stress. At both 48 and 72 h p.i., there was significantly reduced nuclear localization of NF-κB. CVS infection may induce oxidative stress by inhibiting nuclear activation of NF-κB. A rabies virus protein may directly inhibit NF-κB activity. Further investigations are needed to gain a better understanding of the basic mechanisms involved in the oxidative damage associated with rabies virus infection. PMID:22623795

  19. Oxytocin-induced membrane hyperpolarization in pain-sensitive dorsal root ganglia neurons mediated by Ca(2+)/nNOS/NO/KATP pathway.

    PubMed

    Gong, L; Gao, F; Li, J; Li, J; Yu, X; Ma, X; Zheng, W; Cui, S; Liu, K; Zhang, M; Kunze, W; Liu, C Y

    2015-03-19

    Oxytocin (OT) plays an important role in pain modulation and antinociception in the central nervous system. However, little is known about its peripheral effects. This study was conducted to investigate the effect of OT on the electrical properties of neurons in the dorsal root ganglia (DRG) and the underlying mechanisms. DRG neurons from adult rats were acutely dissociated and cultured. Intracellular Ca(2+) was determined by fluorescent microscopy using an indicator dye. The electrical properties of DRG neurons were tested by patch-clamp recording. The oxytocin receptor (OTR) and neuronal nitric oxide synthase (nNOS) on DRG neurons were assessed with immunofluorescence assays. OTR co-localized with nNOS in most of Isolectin B4 (IB4)-binding cultured DRG neurons in rats. OT decreased the excitability, increased the outward current, and evoked the membrane hyperpolarization in cultured DRG neurons. Sodium nitroprusside (SNP), the donor of nitric oxide (NO), exerted similar effects as OT on the membrane potential of cultured DRG neurons. OT increased the production of NO in DRGs and cultured DRG neurons. Pre-treatment of the OTR antagonist atosiban or the selective nNOS inhibitor N-Propyl-l-arginine (NPLA) significantly attenuated the hyperpolarization effect evoked by OT. OT produced a concentration-dependent increase in intracellular Ca(2+) in DRG neurons that responds to capsaicin, which can be attenuated by atosiban, but not by NPLA. OT-evoked membrane hyperpolarization and increase of outward current were distinctly attenuated by glibenclamide, a blocker of ATP-sensitive K(+) (KATP) channel. OT might be an endogenous antinociceptive agent and the peripheral antinociceptive effects of OT are mediated by activation of the Ca(2+)/nNOS/NO/KATP pathway in DRG neurons. PMID:25617653

  20. Activation of CaMKII and ERK1/2 contributes to the time-dependent potentiation of Ca2+ response elicited by repeated application of capsaicin in rat DRG neurons

    PubMed Central

    Daugherty, Stephanie L.; de Groat, William C.

    2011-01-01

    When capsaicin is applied repeatedly to dorsal root ganglion (DRG) neurons for brief periods (10–15 s) at short intervals (5–10 min), the evoked responses rapidly decline, a phenomenon termed tachyphylaxis. In addition to this phenomenon, the present study using Ca2+ imaging revealed that repeated application of capsaicin to rat dissociated DRG neurons at longer intervals (20–40 min) or during multiple applications at short intervals elicited an enhancement of the responses, termed potentiation. The potentiation occurred in 50–60% of the capsaicin-responsive cells, on average representing a 20- to 30% increase in the peak amplitude of the Ca2+ signal, and was maximal at a 40-min application interval. An analysis of the mechanisms underlying potentiation revealed that it was suppressed by block of Ca2+/calmodulin-dependent protein kinase II (CaMKII) with 5 μM KN-93 or block of the activation of extracellular signal-regulated kinase (ERK) 1/2 with 2 μM U-0126. Lowering the extracellular Ca2+ concentration from 2 to 1 mM or pretreatment with deltamethrin (1 μM), which blocks calcineurin and tachyphylaxis, enhanced potentiation. Potentiation was not affected by: 1) inhibition of protein kinase C or protein kinase A, 2) block of the three subtypes of neurokinin receptors, or 3) block of the trafficking of transient receptor potential V1 channel to the membrane. These results indicate that the potentiation is a slowly developing Ca2+-modulated process that is mediated by a complex intracellular signaling pathway involving activation of CaMKII and ERK1/2. Potentiation may be an important peripheral autosensitization mechanism that occurs independently of the pronociceptive effects of inflammatory mediators and neurotrophic factors. PMID:21178121

  1. Activation of CB1 inhibits NGF-induced sensitization of TRPV1 in adult mouse afferent neurons

    PubMed Central

    Wang, Zun-Yi; McDowell, Thomas; Wang, Peiqing; Alvarez, Roxanne; Gomez, Timothy; Bjorling, Dale E.

    2015-01-01

    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 (100 ng/ml) for 30 minutes significantly increased the number of neurons that responded to capsaicin (as indicated by increased intracellular Ca2+ concentration). Pretreatment with the CB1 agonist ACEA (10 nM) 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. PMID:25088915

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

    PubMed Central

    Brelstaff, Jack; Ossola, Bernardino; Neher, Jonas J.; Klingstedt, Therése; Nilsson, K. Peter R.; Goedert, Michel; Spillantini, Maria Grazia; Tolkovsky, Aviva M.

    2015-01-01

    Identification of fluorescent dyes that label the filamentous protein aggregates characteristic of neurodegenerative disease, such as β-amyloid and tau in Alzheimer's disease, in a live cell culture system has previously been a major hurdle. Here we show that pentameric formyl thiophene acetic acid (pFTAA) fulfills 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, an antibody that identifies solely filamentous tau, or MC1, an antibody that identifies a conformational change in tau that is commensurate with neurofibrillary tangle formation in Alzheimer's disease 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 harboring filamentous tau. Treatment with formic acid, which solubilizes 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 and in animal models of several neurodegenerative diseases, as well as in human brains, it will have considerable application in sorting out disease mechanisms and in identifying disease-modifying drugs that will ultimately help establish the mechanisms of neurodegeneration

  3. Adult-born neurons are necessary for extended contextual discrimination.

    PubMed

    Tronel, Sophie; Belnoue, Laure; Grosjean, Noelle; Revest, Jean-Michel; Piazza, Pier-Vincenzo; Koehl, Muriel; Abrous, Djoher Nora

    2012-02-01

    New neurons are continuously produced in the adult dentate gyrus of the hippocampus. It has been shown that one of the functions of adult neurogenesis is to support spatial pattern separation, a process that transforms similar memories into nonoverlapping representations. This prompted us to investigate whether adult-born neurons are required for discriminating two contexts, i.e., for identifying a familiar environment and detect any changes introduced in it. We show that depleting adult-born neurons impairs the animal's ability to disambiguate two contexts after extensive training. These data suggest that the continuous production of new dentate neurons plays a crucial role in extracting and separating efficiently contextual representation in order to discriminate features within events. PMID:21049483

  4. Egr2-neurons control the adult respiratory response to hypercapnia

    PubMed Central

    Ray, Russell S.; Corcoran, Andrea E.; Brust, Rachael D.; Soriano, Laura P.; Nattie, Eugene E.; Dymecki, Susan M.

    2013-01-01

    ‘The early growth response 2 transcription factor, Egr2, establishes a population of brainstem neurons essential for normal breathing at birth. Egr2-null mice die perinatally of respiratory insufficiency characterized by subnormal respiratory rate and severe apneas. Here we bypass this lethality using a noninvasive pharmacogenetic approach to inducibly perturb neuron activity postnatally, and ask if Egr2-neurons control respiration in adult mice. We found that the normal ventilatory increase in response to elevated tissue CO2 was impaired, blunted by 63.1±8.7% after neuron perturbation due to deficits in both respiratory amplitude and frequency. By contrast, room-air breathing was unaffected, suggesting that the drive for baseline breathing may not require those Egr2-neurons manipulated here. Of the multiple brainstem sites proposed to affect ventilation in response to hypercapnia, only the retrotrapezoid nucleus, a portion of the serotonergic raphé, and a portion of the A5 nucleus have a history of Egr2 expression. We recently showed that acute inhibition of serotonergic neurons en masse blunts the CO2 chemoreflex in adults, causing a difference in hypercapnic response of ~50% after neuron perturbation through effects on respiratory amplitude only. The suppressed respiratory frequency upon perturbation of Egr2-neurons thus may stem from non-serotonergic neurons within the Egr2 domain. Perturbation of Egr2-neurons did not affect body temperature, even on exposure to ambient 4 °C. These findings support a model in which Egr2-neurons are a critical component of the respiratory chemoreflex into adulthood. Methodologically, these results highlight how pharmacogenetic approaches allow neuron function to be queried in unanesthetized adult animals, reaching beyond the roadblocks of developmental lethality and compensation as well as the anatomical disturbances associated with invasive methods. PMID:23261662

  5. The Contradictory Effects of Neuronal Hyperexcitation on Adult Hippocampal Neurogenesis.

    PubMed

    Pineda, José R; Encinas, Juan M

    2016-01-01

    Adult hippocampal neurogenesis is a highly plastic process that responds swiftly to neuronal activity. Adult hippocampal neurogenesis can be regulated at the level of neural stem cell recruitment and activation, progenitor proliferation, as well as newborn cell survival and differentiation. An "excitation-neurogenesis" rule was proposed after the demonstration of the capability of cultured neural stem and progenitor cells to intrinsically sense neuronal excitatory activity. In vivo, this property has remained elusive although recently the direct response of neural stem cells to GABA in the hippocampus via GABAA receptors has evidenced a mechanism for a direct talk between neurons and neural stem cells. As it is pro-neurogenic, the effect of excitatory neuronal activity has been generally considered beneficial. But what happens in situations of neuronal hyperactivity in which neurogenesis can be dramatically boosted? In animal models, electroconvulsive shock markedly increases neurogenesis. On the contrary, in epilepsy rodent models, seizures induce the generation of misplaced neurons with abnormal morphological and electrophysiological properties, namely aberrant neurogenesis. We will herein discuss what is known about the mechanisms of influence of neurons on neural stem cells, as well as the severe effects of neuronal hyperexcitation on hippocampal neurogenesis. PMID:26973452

  6. The Contradictory Effects of Neuronal Hyperexcitation on Adult Hippocampal Neurogenesis

    PubMed Central

    Pineda, José R.; Encinas, Juan M.

    2016-01-01

    Adult hippocampal neurogenesis is a highly plastic process that responds swiftly to neuronal activity. Adult hippocampal neurogenesis can be regulated at the level of neural stem cell recruitment and activation, progenitor proliferation, as well as newborn cell survival and differentiation. An “excitation-neurogenesis” rule was proposed after the demonstration of the capability of cultured neural stem and progenitor cells to intrinsically sense neuronal excitatory activity. In vivo, this property has remained elusive although recently the direct response of neural stem cells to GABA in the hippocampus via GABAA receptors has evidenced a mechanism for a direct talk between neurons and neural stem cells. As it is pro-neurogenic, the effect of excitatory neuronal activity has been generally considered beneficial. But what happens in situations of neuronal hyperactivity in which neurogenesis can be dramatically boosted? In animal models, electroconvulsive shock markedly increases neurogenesis. On the contrary, in epilepsy rodent models, seizures induce the generation of misplaced neurons with abnormal morphological and electrophysiological properties, namely aberrant neurogenesis. We will herein discuss what is known about the mechanisms of influence of neurons on neural stem cells, as well as the severe effects of neuronal hyperexcitation on hippocampal neurogenesis. PMID:26973452

  7. Modulation of Voltage-Gated Sodium Channels by Activation of Tumor Necrosis Factor Receptor-1 and Receptor-2 in Small DRG Neurons of Rats

    PubMed Central

    Leo, M.; Argalski, S.; Schäfers, M.; Hagenacker, T.

    2015-01-01

    Tumor necrosis factor- (TNF-) α is a proinflammatory cytokine involved in the development and maintenance of inflammatory and neuropathic pain. Its effects are mediated by two receptors, TNF receptor-1 (TNFR-1) and TNF receptor-2 (TNFR-2). These receptors play a crucial role in the sensitization of voltage-gated sodium channels (VGSCs), a key mechanism in the pathogenesis of chronic pain. Using the whole-cell patch-clamp technique, we examined the influence of TNFR-1 and TNFR-2 on VGSCs and TTX-resistant NaV1.8 channels in isolated rat dorsal root ganglion neurons by using selective TNFR agonists. The TNFR-1 agonist R32W (10 pg/mL) caused an increase in the VGSC current (INa(V)) by 27.2 ± 5.1%, while the TNFR-2 agonist D145 (10 pg/mL) increased the current by 44.9 ± 2.6%. This effect was dose dependent. Treating isolated NaV1.8 with R32W (100 pg/mL) resulted in an increase in INaV(1.8) by 18.9 ± 1.6%, while treatment with D145 (100 pg/mL) increased the current by 14.5 ± 3.7%. Based on the current-voltage relationship, 10 pg of R32W or D145 led to an increase in INa(V) in a bell-shaped, voltage-dependent manner with a maximum effect at −30 mV. The effects of TNFR activation on VGSCs promote excitation in primary afferent neurons and this might explain the sensitization mechanisms associated with neuropathic and inflammatory pain. PMID:26504355

  8. Neurite growth acceleration of adult Dorsal Root Ganglion neurons illuminated by low-level Light Emitting Diode light at 645 nm.

    PubMed

    Burland, Marion; Paris, Lambert; Quintana, Patrice; Bec, Jean-Michel; Diouloufet, Lucie; Sar, Chamroeun; Boukhaddaoui, Hassan; Charlot, Benoit; Braga Silva, Jefferson; Chammas, Michel; Sieso, Victor; Valmier, Jean; Bardin, Fabrice

    2015-06-01

    The effect of a 645 nm Light Emitting Diode (LED) light irradiation on the neurite growth velocity of adult Dorsal Root Ganglion (DRG) neurons with peripheral axon injury 4-10 days before plating and without previous injury was investigated. The real amount of light reaching the neurons was calculated by taking into account the optical characteristics of the light source and of media in the light path. The knowledge of these parameters is essential to be able to compare results of the literature and a way to reduce inconsistencies. We found that 4 min irradiation of a mean irradiance of 11.3 mW/cm(2) (corresponding to an actual irradiance reaching the neurons of 83 mW/cm(2)) induced a 1.6-fold neurite growth acceleration on non-injured neurons and on axotomized neurons. Although the axotomized neurons were naturally already in a rapid regeneration process, an enhancement was found to occur while irradiating with the LED light, which may be promising for therapy applications. Dorsal Root Ganglion neurons (A) without previous injury and (B) subjected to a conditioning injury. PMID:25077453

  9. Roles of mitochondria and temperature in the control of intracellular calcium in adult rat sensory neurons.

    PubMed

    Kang, S H; Carl, A; McHugh, J M; Goff, H R; Kenyon, J L

    2008-04-01

    We recorded Ca2+ current and intracellular Ca2+ ([Ca2+](i)) in isolated adult rat dorsal root ganglion (DRG) neurons at 20 and 30 degrees C. In neurons bathed in tetraethylammonium and dialyzed with cesium, warming reduced resting [Ca2+](i) from 87 to 49 nM and the time constant of the decay of [Ca2+](i) transients (tau(r)) from 1.3 to 0.99s (Q(10)=1.4). The Buffer Index, the ratio between Ca2+ influx and Delta[Ca2+](i) (f I(ca)d(t)/Delta[Ca2+]i) , increased two- to threefold with warming. Neither inhibition of the plasma membrane Ca2+ -ATPase by intracellular sodium orthovanadate nor inhibition of Ca2+ uptake by the endoplasmic reticulum by thapsigargin plus ryanodine were necessary for the effects of warming on these parameters. In contrast, inhibition of the mitochondrial Ca2+ uniporter by intracellular ruthenium red largely reversed the effects of warming. Carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP, 500 nM) increased resting [Ca2+](i) at 30 degrees C. Ten millimolar intracellular sodium prolonged the recovery of [Ca2+](i) transients to 10-40s. This effect was reversed by an inhibitor of mitochondrial Na(+)/Ca2+ -exchange (CGP 37157, 10 microM). Thus, mitochondrial Ca2+ uptake is necessary for the temperature-dependent increase in Ca2+ buffering and mitochondrial Ca2+ fluxes contribute to the control of [Ca2+](i) between 50 and 150 nM at 30 degrees C. PMID:17716728

  10. Effects of serum immunoglobulins from patients with complex regional pain syndrome (CRPS) on depolarisation-induced calcium transients in isolated dorsal root ganglion (DRG) neurons.

    PubMed

    Reilly, Joanne M; Dharmalingam, Backialakshmi; Marsh, Stephen J; Thompson, Victoria; Goebel, Andreas; Brown, David A

    2016-03-01

    Complex regional pain syndrome (CRPS) is thought to have an auto-immune component. One such target recently proposed from the effects of auto-immune IgGs on Ca(2+) transients in cardiac myocytes and cell lines is the α1-adrenoceptor. We have tested whether such IgGs exerted comparable effects on nociceptive sensory neurons isolated from rat dorsal root ganglia. Depolarisation-induced [Ca(2+)]i transients were generated by applying 30 mM KCl for 2 min and monitored by Fura-2 fluorescence imaging. No IgGs tested (including 3 from CRPS patients) had any significant effect on these [Ca(2+)]i transients. However, IgG from one CRPS patient consistently and significantly reduced the K(+)-induced response of cells that had been pre-incubated for 24h with a mixture of inflammatory mediators (1 μM histamine, 5-hydroxytryptamine, bradykinin and PGE2). Since this pre-incubation also appeared to induce a comparable inhibitory response to the α1-agonist phenylephrine, this is compatible with the α1-adrenoceptor as a target for CRPS auto-immunity. A mechanism whereby this might enhance pain is suggested. PMID:26708558

  11. Pan-neuronal maturation but not neuronal subtype differentiation of adult neural stem cells is mechanosensitive

    PubMed Central

    Keung, Albert J.; Dong, Meimei; Schaffer, David V.; Kumar, Sanjay

    2013-01-01

    Most past studies of the biophysical regulation of stem cell differentiation have focused on initial lineage commitment or proximal differentiation events. It would be valuable to understand whether biophysical inputs also influence distal endpoints more closely associated with physiological function, such as subtype specification in neuronal differentiation. To explore this question, we cultured adult neural stem cells (NSCs) on variable stiffness ECMs under conditions that promote neuronal fate commitment for extended time periods to allow neuronal subtype differentiation. We find that ECM stiffness does not modulate the expression of NeuroD1 and TrkA/B/C or the percentages of pan-neuronal, GABAergic, or glutamatergic neuronal subtypes. Interestingly, however, an ECM stiffness of 700 Pa maximizes expression of pan-neuronal markers. These results suggest that a wide range of stiffnesses fully permit pan-neuronal NSC differentiation, that an intermediate stiffness optimizes expression of pan-neuronal genes, and that stiffness does not impact commitment to particular neuronal subtypes. PMID:23660869

  12. Adult neurogenesis restores dopaminergic neuronal loss in the olfactory bulb.

    PubMed

    Lazarini, Françoise; Gabellec, Marie-Madeleine; Moigneu, Carine; de Chaumont, Fabrice; Olivo-Marin, Jean-Christophe; Lledo, Pierre-Marie

    2014-10-22

    Subventricular zone (SVZ) neurogenesis continuously provides new GABA- and dopamine (DA)-containing interneurons for the olfactory bulb (OB) in most adult mammals. DAergic interneurons are located in the glomerular layer (GL) where they participate in the processing of sensory inputs. To examine whether adult neurogenesis might contribute to regeneration after circuit injury in mice, we induce DAergic neuronal loss by injecting 6-hydroxydopamine (6-OHDA) in the dorsal GL or in the right substantia nigra pars compacta. We found that a 6-OHDA treatment of the OB produces olfactory deficits and local inflammation and partially decreases the number of neurons expressing the enzyme tyrosine hydroxylase (TH) near the injected site. Blockade of inflammation by minocycline treatment immediately after the 6-OHDA administration rescued neither TH(+) interneuron number nor the olfactory deficits, suggesting that the olfactory impairments are most likely linked to TH(+) cell death and not to microglial activation. TH(+) interneuron number was restored 1 month later. This rescue resulted at least in part from enhanced recruitment of immature neurons targeting the lesioned GL area. Seven days after 6-OHDA lesion in the OB, we found that the integration of lentivirus-labeled adult-born neurons was biased: newly formed neurons were preferentially incorporated into glomerular circuits of the lesioned area. Behavioral rehabilitation occurs 2 months after lesion. This study establishes a new model into which loss of DAergic cells could be compensated by recruiting newly formed neurons. We propose that adult neurogenesis not only replenishes the population of DAergic bulbar neurons but that it also restores olfactory sensory processing. PMID:25339754

  13. Adult myelination: wrapping up neuronal plasticity

    PubMed Central

    O’Rourke, Megan; Gasperini, Robert; Young, Kaylene M.

    2014-01-01

    In this review, we outline the major neural plasticity mechanisms that have been identified in the adult central nervous system (CNS), and offer a perspective on how they regulate CNS function. In particular we examine how myelin plasticity can operate alongside neurogenesis and synaptic plasticity to influence information processing and transfer in the mature CNS. PMID:25221576

  14. A comparison of peripheral and central axotomy effects on neurofilament and tubulin gene expression in rat dorsal root ganglion neurons

    SciTech Connect

    Wong, J.; Oblinger, M.M. )

    1990-07-01

    The expression of major cytoskeletal protein mRNAs was studied in adult rat dorsal root ganglion (DRG) neurons after crushing either their central or peripheral branch axons. mRNA levels in DRG neurons were examined by quantitative in situ hybridization with radiolabeled cDNA probes specific for the low-molecular-weight neurofilament protein (NF-L) and beta-tubulin. The large-sized (greater than 1000 microns 2) neurons which give rise to myelinated axons in lumbar ganglia (L4 and L5) were studied 1 d through 8 weeks after either dorsal root or sciatic nerve crush. NF-L and beta-tubulin mRNA levels in axotomized DRG neurons were compared to those in contralateral control DRG neurons, as well as to those in normal (completely untreated) DRG cells. In the case of NF-L mRNA, changes were observed after central as well as peripheral branch axotomy and the time course and magnitude of changes were similar after both types of axotomy. NF-L mRNA levels initially decreased (first 2 weeks after crush) and then began to return towards control levels at longer survival times. Similar, but less pronounced, changes in NF-L mRNA levels also occurred in contralateral DRG neurons (which were uninjured); the changes in contralateral neurons were not simply a result of surgical stress since no changes in NF-L mRNA levels were observed in sham-operated DRG neurons. In the case of tubulin mRNA, changes were observed after central as well as peripheral branch axotomy by in situ hybridization, but the time course and magnitude of changes were different after each type of axotomy.

  15. Retinoic acid affects calcium signaling in adult molluscan neurons.

    PubMed

    Vesprini, Nicholas D; Dawson, Taylor F; Yuan, Ye; Bruce, Doug; Spencer, Gaynor E

    2015-01-01

    Retinoic acid, the active metabolite of vitamin A, is important for nervous system development, regeneration, as well as cognitive functions of the adult central nervous system. These central nervous system functions are all highly dependent on neuronal activity. Retinoic acid has previously been shown to induce changes in the firing properties and action potential waveforms of adult molluscan neurons in a dose- and isomer-dependent manner. In this study, we aimed to determine the cellular pathways by which retinoic acid might exert such effects, by testing the involvement of pathways previously shown to be affected by retinoic acid. We demonstrated that the ability of all-trans retinoic acid (atRA) to induce electrophysiological changes in cultured molluscan neurons was not prevented by inhibitors of protein synthesis, protein kinase A or phospholipase C. However, we showed that atRA was capable of rapidly reducing intracellular calcium levels in the same dose- and isomer-dependent manner as shown previously for changes in neuronal firing. Moreover, we also demonstrated that the transmembrane ion flux through voltage-gated calcium channels was rapidly modulated by retinoic acid. In particular, the peak current density was reduced and the inactivation rate was increased in the presence of atRA, over a similar time course as the changes in cell firing and reductions in intracellular calcium. These studies provide further evidence for the ability of atRA to induce rapid effects in mature neurons. PMID:25343782

  16. Phagocytic activity of neuronal progenitors regulates adult neurogenesis.

    PubMed

    Lu, Zhenjie; Elliott, Michael R; Chen, Yubo; Walsh, James T; Klibanov, Alexander L; Ravichandran, Kodi S; Kipnis, Jonathan

    2011-09-01

    Whereas thousands of new neurons are generated daily during adult life, only a fraction of them survive and become part of neural circuits; the rest die, and their corpses are presumably cleared by resident phagocytes. How the dying neurons are removed and how such clearance influences neurogenesis are not well understood. Here, we identify an unexpected phagocytic role for the doublecortin (DCX)-positive neuronal progenitor cells during adult neurogenesis. Our in vivo and ex vivo studies demonstrate that DCX(+) cells comprise a significant phagocytic population within the neurogenic zones. Intracellular engulfment protein ELMO1, which promotes Rac activation downstream of phagocytic receptors, was required for phagocytosis by DCX(+) cells. Disruption of engulfment in vivo genetically (in Elmo1-null mice) or pharmacologically (in wild-type mice) led to reduced uptake by DCX(+) cells, accumulation of apoptotic nuclei in the neurogenic niches and impaired neurogenesis. Collectively, these findings indicate a paradigm wherein DCX(+) neuronal precursors also serve as phagocytes, and that their phagocytic activity critically contributes to neurogenesis in the adult brain. PMID:21804544

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

    PubMed Central

    2012-01-01

    Background Itch is one of the major somatosensory modalities. Some recent findings have proposed that gastrin releasing peptide (Grp) is expressed in a subset of dorsal root ganglion (DRG) neurons and functions as a selective neurotransmitter for transferring itch information to spinal cord interneurons. However, expression data from public databases and earlier literatures indicate that Grp mRNA is only detected in dorsal spinal cord (dSC) whereas its family member neuromedin B (Nmb) is highly expressed in DRG neurons. These contradictory results argue that a thorough characterization of the expression of Grp and Nmb is warranted. Findings Grp mRNA is highly expressed in dSC but is barely detectable in DRGs of juvenile and adult mice. Anti-bombesin serum specifically recognizes Grp but not Nmb. Grp is present in a small number of small-diameter DRG neurons and in abundance in layers I and II of the spinal cord. The reduction of dSC Grp after dorsal root rhizotomy is significantly different from those of DRG derived markers but similar to that of a spinal cord neuronal marker. Double fluorescent in situ of Nmb and other molecular markers indicate that Nmb is highly and selectively expressed in nociceptive and itch-sensitive DRG neurons. Conclusion The majority of dSC Grp is synthesized locally in dorsal spinal cord neurons. On the other hand, Nmb is highly expressed in pain- and itch-sensing DRG neurons. Our findings provide direct anatomic evidence that Grp could function locally in the dorsal spinal cord in addition to its roles in DRG neurons and that Nmb has potential roles in nociceptive and itch-sensitive neurons. These results will improve our understanding about roles of Grp and Nmb in mediating itch sensation. PMID:22776446

  18. Protracted elevation of neuronal nitric oxide synthase immunoreactivity in axotomised adult pudendal motor neurons

    PubMed Central

    PULLEN, A. H.; HUMPHREYS, P.

    1999-01-01

    Neuronal nitric oxide synthase immunoreactivity (NOS1-ir) in sacral motor neurons of normal adult cats was compared with that in cats surviving 1–10 wk after unilateral transection and ligation of the pudendal nerve. Levels of immunostaining were measured by microdensitometry. In nonoperated cats 60% of motor neurons in the ventrolateral nucleus (VL) and Onuf's nucleus (ON) showed high levels of NOS1-ir with lower NOS1-ir in 40%. Following axotomy, motor neurons in ON on both sides of the cord showed an acute rise in mean level of NOS1-ir at 1 wk, with a further increase at 2 wk. Mean levels of NOS1-ir in the ipsilateral and contralateral ON remained elevated at 10 wk after axotomy. Elevation of NOS1-ir occurred in the VL with a similar time-course to that in ON, implying a wider response in motor nuclei synaptically coupled to ON. Measurements of neuronal size in ON and VL revealed an increase in neuronal size in ON but not VL, indicating increased NOS1-ir in ON was not an artifact of neuronal atrophy. The proportion of motor neurons in ON and VL possessing higher levels of NOS1-ir increased from 60% in controls to 100% at 2–3 wk postaxotomy. The proportion slightly declined by 8 wk due to re-emergence of motor neurons exhibiting low NOS1-ir, but remained greater than normal at 10 wk in both nuclei. Based on evidence from related analyses of synaptology, we argue that acute axotomy induced alterations in presynaptic complement which increased overall Ca2+ influx and thereby stimulated NOS1-ir. PMID:10445823

  19. Coupled Activation of Primary Sensory Neurons Contributes to Chronic Pain.

    PubMed

    Kim, Yu Shin; Anderson, Michael; Park, Kyoungsook; Zheng, Qin; Agarwal, Amit; Gong, Catherine; Saijilafu; Young, LeAnne; He, Shaoqiu; LaVinka, Pamela Colleen; Zhou, Fengquan; Bergles, Dwight; Hanani, Menachem; Guan, Yun; Spray, David C; Dong, Xinzhong

    2016-09-01

    Primary sensory neurons in the DRG play an essential role in initiating pain by detecting painful stimuli in the periphery. Tissue injury can sensitize DRG neurons, causing heightened pain sensitivity, often leading to chronic pain. Despite the functional importance, how DRG neurons function at a population level is unclear due to the lack of suitable tools. Here we developed an imaging technique that allowed us to simultaneously monitor the activities of >1,600 neurons/DRG in live mice and discovered a striking neuronal coupling phenomenon that adjacent neurons tend to activate together following tissue injury. This coupled activation occurs among various neurons and is mediated by an injury-induced upregulation of gap junctions in glial cells surrounding DRG neurons. Blocking gap junctions attenuated neuronal coupling and mechanical hyperalgesia. Therefore, neuronal coupling represents a new form of neuronal plasticity in the DRG and contributes to pain hypersensitivity by "hijacking" neighboring neurons through gap junctions. PMID:27568517

  20. Connexins and pannexins in neuronal development and adult neurogenesis.

    PubMed

    Swayne, Leigh Anne; Bennett, Steffany A L

    2016-01-01

    Connexins and pannexins share very similar structures and functions; they also exhibit overlapping expression in many stages of neuronal development. Here, we review evidence implicating connexin- and pannexin-mediated communication in the regulation of the birth and development of neurons, specifically Cx26, Cx30, Cx32, Cx36, Cx43, Cx45, Panx1, and Panx2. We begin by dissecting the involvement of these proteins in the generation and development of new neurons in the embryonic, postnatal, and adult brain. Next we briefly outline common mechanisms employed by both pannexins and connexins in these roles, including modulation of purinergic receptor signalling and signalling nexus functions. Throughout this review we highlight developing themes as well as important gaps in knowledge to be bridged. PMID:27230672

  1. Electrophysiological Profiles of Induced Neurons Converted Directly from Adult Human Fibroblasts Indicate Incomplete Neuronal Conversion

    PubMed Central

    Koppensteiner, Peter; Boehm, Stefan

    2014-01-01

    Abstract The direct conversion of human fibroblasts to neuronal cells, termed human induced neuronal (hiN) cells, has great potential for future clinical advances. However, previous studies have not provided an in-depth analysis of electrophysiological properties of adult fibroblast-derived hiN cultures. We have examined the electrophysiological profile of hiN cells by measuring passive and active membrane properties, as well as spontaneous and evoked neurotransmission. We found that hiN cells exhibited passive membrane properties equivalent to perinatal rodent neurons. In addition, 30% of hiN cells were incapable of action potential (AP) generation and did not exhibit rectifying membrane currents, and none of the cells displayed firing patterns of typical glutamatergic pyramidal neurons. Finally, hiN cells exhibited neither spontaneous nor evoked neurotransmission. Our results suggest that current methods used to produce hiN cells provide preparations in which cells do not achieve the cellular properties of fully mature neurons, rendering these cells inadequate to investigate pathophysiological mechanisms. PMID:25437871

  2. White Matter Neurons in Young Adult and Aged Rhesus Monkey

    PubMed Central

    Mortazavi, Farzad; Wang, Xiyue; Rosene, Douglas L.; Rockland, Kathleen S.

    2016-01-01

    In humans and non-human primates (NHP), white matter neurons (WMNs) persist beyond early development. Their functional importance is largely unknown, but they have both corticothalamic and corticocortical connectivity and at least one subpopulation has been implicated in vascular regulation and sleep. Several other studies have reported that the density of WMNs in humans is altered in neuropathological or psychiatric conditions. The present investigation evaluates and compares the density of superficial and deep WMNs in frontal (FR), temporal (TE), and parietal (Par) association regions of four young adult and four aged male rhesus monkeys. A major aim was to determine whether there was age-related neuronal loss, as might be expected given the substantial age-related changes known to occur in the surrounding white matter environment. Neurons were visualized by immunocytochemistry for Neu-N in coronal tissue sections (30 μm thickness), and neuronal density was assessed by systematic random sampling. Per 0.16 mm2 sampling box, this yielded about 40 neurons in the superficial WM and 10 in the deep WM. Consistent with multiple studies of cell density in the cortical gray matter of normal brains, neither the superficial nor deep WM populations showed statistically significant age-related neuronal loss, although we observed a moderate decrease with age for the deep WMNs in the frontal region. Morphometric analyses, in contrast, showed significant age effects in soma size and circularity. In specific, superficial WMNs were larger in FR and Par WM regions of the young monkeys; but in the TE, these were larger in the older monkeys. An age effect was also observed for soma circularity: superficial WMNs were more circular in FR and Par of the older monkeys. This second, morphometric result raises the question of whether other age-related morphological, connectivity, or molecular changes occur in the WMNs. These could have multiple impacts, given the wide range of putative

  3. Modulation of adult-born neurons in the inflamed hippocampus

    PubMed Central

    Belarbi, Karim; Rosi, Susanna

    2013-01-01

    Throughout life new neurons are continuously added to the hippocampal circuitry involved with spatial learning and memory. These new cells originate from neural precursors in the subgranular zone of the dentate gyrus, migrate into the granule cell layer, and integrate into neural networks encoding spatial and contextual information. This process can be influenced by several environmental and endogenous factors and is modified in different animal models of neurological disorders. Neuroinflammation, as defined by the presence of activated microglia, is a common key factor to the progression of neurological disorders. Analysis of the literature shows that microglial activation impacts not only the production, but also the migration and the recruitment of new neurons. The impact of microglia on adult-born neurons appears much more multifaceted than ever envisioned before, combining both supportive and detrimental effects that are dependent upon the activation phenotype and the factors being released. The development of strategies aimed to change microglia toward states that promote functional neurogenesis could therefore offer novel therapeutic opportunities against neurological disorders associated with cognitive deficits and neuroinflammation. The present review summarizes the current knowledge on how production, distribution, and recruitment of new neurons into behaviorally relevant neural networks are modified in the inflamed hippocampus. PMID:24046730

  4. Environmental Impact on Direct Neuronal Reprogramming In Vivo in the Adult Brain

    PubMed Central

    López-Juárez, Alejandro; Howard, Jennifer; Sakthivel, Bhuvaneswari; Aronow, Bruce; Campbell, Kenneth; Nakafuku, Masato

    2013-01-01

    Direct reprogramming of non-neuronal cells to generate new neurons is a promising approach to repair damaged brains. Impact of the in vivo environment on neuronal reprogramming, however, is poorly understood. Here we show that regional differences and injury conditions have significant influence on the efficacy of reprogramming and subsequent survival of newly generated neurons in the adult rodent brain. A combination of local exposure to growth factors and retrovirus-mediated overexpression of the neurogenic transcription factor Neurogenin2 (Neurog2) can induce new neurons from non-neuronal cells in the adult neocortex and striatum where neuronal turnover is otherwise very limited. These two regions respond to growth factors and Neurog2 differently and instruct new neurons to exhibit distinct molecular phenotypes. Moreover, ischemic insult differentially affects differentiation of new neurons in these regions. These results demonstrate strong environmental impact on direct neuronal reprogramming in vivo. PMID:23974433

  5. SynCAM 1 improves survival of adult-born neurons by accelerating synapse maturation.

    PubMed

    Doengi, Michael; Krupp, Alexander J; Körber, Nils; Stein, Valentin

    2016-03-01

    The survival of adult-born dentate gyrus granule cells critically depends on their synaptic integration into the existing neuronal network. Excitatory inputs are thought to increase the survival rate of adult born neurons. Therefore, whether enhancing the stability of newly formed excitatory synapses by overexpressing the synaptic cell adhesion molecule SynCAM 1 improves the survival of adult-born neurons was tested. Here it is shown that overexpression of SynCAM 1 improves survival of adult-born neurons, but has no effect on the proliferation rate of precursor cells. As expected, overexpression of SynCAM 1 increased the synapse density in adult-born granule neurons. While adult-born granule neurons have very few functional synapses 15 days after birth, it was found that at this age adult-born neurons in SynCAM 1 overexpressing mice exhibited around three times more excitatory synapses, which were stronger than synapses of adult-born neurons of control littermates. In summary, the data indicated that additional SynCAM 1 accelerated synapse maturation, which improved the stability of newly formed synapses and in turn increased the likelihood of survival of adult-born neurons. © 2015 Wiley Periodicals, Inc. PMID:26332750

  6. GABA regulates synaptic integration of newly generated neurons in the adult brain

    NASA Astrophysics Data System (ADS)

    Ge, Shaoyu; Goh, Eyleen L. K.; Sailor, Kurt A.; Kitabatake, Yasuji; Ming, Guo-Li; Song, Hongjun

    2006-02-01

    Adult neurogenesis, the birth and integration of new neurons from adult neural stem cells, is a striking form of structural plasticity and highlights the regenerative capacity of the adult mammalian brain. Accumulating evidence suggests that neuronal activity regulates adult neurogenesis and that new neurons contribute to specific brain functions. The mechanism that regulates the integration of newly generated neurons into the pre-existing functional circuitry in the adult brain is unknown. Here we show that newborn granule cells in the dentate gyrus of the adult hippocampus are tonically activated by ambient GABA (γ-aminobutyric acid) before being sequentially innervated by GABA- and glutamate-mediated synaptic inputs. GABA, the major inhibitory neurotransmitter in the adult brain, initially exerts an excitatory action on newborn neurons owing to their high cytoplasmic chloride ion content. Conversion of GABA-induced depolarization (excitation) into hyperpolarization (inhibition) in newborn neurons leads to marked defects in their synapse formation and dendritic development in vivo. Our study identifies an essential role for GABA in the synaptic integration of newly generated neurons in the adult brain, and suggests an unexpected mechanism for activity-dependent regulation of adult neurogenesis, in which newborn neurons may sense neuronal network activity through tonic and phasic GABA activation.

  7. Ultrastructural characteristics of human adult and infant cerebral cortical neurons.

    PubMed Central

    Ong, W Y; Garey, L J

    1991-01-01

    Biopsy specimens of human cerebral cortex from three adults and two infants were studied by correlating their light microscopic features in semithin sections with their ultrastructural characteristics. There was good tissue preservation, due to a minimum delay between obtaining the specimens and fixation. Pyramidal cells had a prominent apical dendrite, fine heterochromatin clumps in the nucleus and generally small numbers of cytoplasmic organelles, except for numerous free ribosomes in some of the large pyramids of Layers III to VI. Non-pyramidal cells lacked an apical dendrite and were further classified, on size and ultrastructure, into small, medium and large types. Large numbers of asymmetrical and symmetrical synapses were present in the neuropil but very few axosomatic synapses were found in the human cerebral cortex compared with subhuman primates and other mammals. Some symmetrical synapses were characterised by the presence of wide pre- and postsynaptic densities. The same general features of the adult cortex were also encountered in the infant, with certain exceptions. Many of the infant neurons had less densely packed heterochromatin, but greater numbers of free ribosomes, compared with the adult, and lipofuscin was absent. There was a total absence of myelinated fibres from the infant cortex; more large diameter dendrites were present than in the adult and axosomatic synapses were commoner. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 PMID:2050578

  8. Membrane potential dye imaging of ventromedial hypothalamus neurons from adult mice to study glucose sensing.

    PubMed

    Vazirani, Reema P; Fioramonti, Xavier; Routh, Vanessa H

    2013-01-01

    Studies of neuronal activity are often performed using neurons from rodents less than 2 months of age due to the technical difficulties associated with increasing connective tissue and decreased neuronal viability that occur with age. Here, we describe a methodology for the dissociation of healthy hypothalamic neurons from adult-aged mice. The ability to study neurons from adult-aged mice allows the use of disease models that manifest at a later age and might be more developmentally accurate for certain studies. Fluorescence imaging of dissociated neurons can be used to study the activity of a population of neurons, as opposed to using electrophysiology to study a single neuron. This is particularly useful when studying a heterogeneous neuronal population in which the desired neuronal type is rare such as for hypothalamic glucose sensing neurons. We utilized membrane potential dye imaging of adult ventromedial hypothalamic neurons to study their responses to changes in extracellular glucose. Glucose sensing neurons are believed to play a role in central regulation of energy balance. The ability to study glucose sensing in adult rodents is particularly useful since the predominance of diseases related to dysfunctional energy balance (e.g. obesity) increase with age. PMID:24326343

  9. Membrane Potential Dye Imaging of Ventromedial Hypothalamus Neurons From Adult Mice to Study Glucose Sensing

    PubMed Central

    Vazirani, Reema P.; Fioramonti, Xavier; Routh, Vanessa H.

    2013-01-01

    Studies of neuronal activity are often performed using neurons from rodents less than 2 months of age due to the technical difficulties associated with increasing connective tissue and decreased neuronal viability that occur with age. Here, we describe a methodology for the dissociation of healthy hypothalamic neurons from adult-aged mice. The ability to study neurons from adult-aged mice allows the use of disease models that manifest at a later age and might be more developmentally accurate for certain studies. Fluorescence imaging of dissociated neurons can be used to study the activity of a population of neurons, as opposed to using electrophysiology to study a single neuron. This is particularly useful when studying a heterogeneous neuronal population in which the desired neuronal type is rare such as for hypothalamic glucose sensing neurons. We utilized membrane potential dye imaging of adult ventromedial hypothalamic neurons to study their responses to changes in extracellular glucose. Glucose sensing neurons are believed to play a role in central regulation of energy balance. The ability to study glucose sensing in adult rodents is particularly useful since the predominance of diseases related to dysfunctional energy balance (e.g. obesity) increase with age. PMID:24326343

  10. Expression of polysialylated neural cell adhesion molecules on adult stem cells after neuronal differentiation of inner ear spiral ganglion neurons

    SciTech Connect

    Park, Kyoung Ho; Yeo, Sang Won; Troy, Frederic A.

    2014-10-17

    Highlights: • PolySia expressed on neurons primarily during early stages of neuronal development. • PolySia–NCAM is expressed on neural stem cells from adult guinea pig spiral ganglion. • PolySia is a biomarker that modulates neuronal differentiation in inner ear stem cells. - Abstract: During brain development, polysialylated (polySia) neural cell adhesion molecules (polySia–NCAMs) modulate cell–cell adhesive interactions involved in synaptogenesis, neural plasticity, myelination, and neural stem cell (NSC) proliferation and differentiation. Our findings show that polySia–NCAM is expressed on NSC isolated from adult guinea pig spiral ganglion (GPSG), and in neurons and Schwann cells after differentiation of the NSC with epidermal, glia, fibroblast growth factors (GFs) and neurotrophins. These differentiated cells were immunoreactive with mAb’s to polySia, NCAM, β-III tubulin, nestin, S-100 and stained with BrdU. NSC could regenerate and be differentiated into neurons and Schwann cells. We conclude: (1) polySia is expressed on NSC isolated from adult GPSG and on neurons and Schwann cells differentiated from these NSC; (2) polySia is expressed on neurons primarily during the early stage of neuronal development and is expressed on Schwann cells at points of cell–cell contact; (3) polySia is a functional biomarker that modulates neuronal differentiation in inner ear stem cells. These new findings suggest that replacement of defective cells in the inner ear of hearing impaired patients using adult spiral ganglion neurons may offer potential hope to improve the quality of life for patients with auditory dysfunction and impaired hearing disorders.

  11. The Complete Genome Sequences, Unique Mutational Spectra, and Developmental Potency of Adult Neurons Revealed by Cloning.

    PubMed

    Hazen, Jennifer L; Faust, Gregory G; Rodriguez, Alberto R; Ferguson, William C; Shumilina, Svetlana; Clark, Royden A; Boland, Michael J; Martin, Greg; Chubukov, Pavel; Tsunemoto, Rachel K; Torkamani, Ali; Kupriyanov, Sergey; Hall, Ira M; Baldwin, Kristin K

    2016-03-16

    Somatic mutation in neurons is linked to neurologic disease and implicated in cell-type diversification. However, the origin, extent, and patterns of genomic mutation in neurons remain unknown. We established a nuclear transfer method to clonally amplify the genomes of neurons from adult mice for whole-genome sequencing. Comprehensive mutation detection and independent validation revealed that individual neurons harbor ∼100 unique mutations from all classes but lack recurrent rearrangements. Most neurons contain at least one gene-disrupting mutation and rare (0-2) mobile element insertions. The frequency and gene bias of neuronal mutations differ from other lineages, potentially due to novel mechanisms governing postmitotic mutation. Fertile mice were cloned from several neurons, establishing the compatibility of mutated adult neuronal genomes with reprogramming to pluripotency and development. PMID:26948891

  12. Nanotherapeutics of PTEN Inhibitor with Mesoporous Silica Nanocarrier Effective for Axonal Outgrowth of Adult Neurons.

    PubMed

    Kim, Min Soo; El-Fiqi, Ahmed; Kim, Jong-Wan; Ahn, Hong-Sun; Kim, Hyukmin; Son, Young-Jin; Kim, Hae-Won; Hyun, Jung Keun

    2016-07-27

    Development of therapeutic strategies such as effective drug delivery is an urgent and yet unmet need for repair of damaged nervous systems. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) regulates axonal regrowth of central and peripheral nervous systems; its inhibition, meanwhile, facilitates axonal outgrowth of injured neurons. Here we show that nanotherapeutics based on mesoporous silica nanoparticles loading PTEN-inhibitor bisperoxovanadium (BpV) are effective for delivery of drug molecules and consequent improvement of axonal outgrowth. Mesoporous nanocarriers loaded BpV drug at large amount (27 μg per 1 mg of carrier), and released sustainably over 10 d. Nanocarrier-BpV treatment of primary neurons from the dorsal root ganglions (DRGs) of rats and mice at various concentrations induced them to actively take up the nanocomplexes with an uptake efficiency as high as 85%. The nanocomplex-administered neurons exhibited significantly enhanced axonal outgrowth compared with those treated with free-BpV drug. The expression of a series of proteins involved in PTEN inhibition and downstream signaling was substantially up-/down-regulated by the nanocarrier-BpV system. Injection of the nanocarriers into neural tissues (DRG, brain cortex, and spinal cord), moreover, demonstrated successful integration into neurons, glial cells, oligodendrocytes, and macrophages, suggesting the possible nanotherapeutics applications in vivo. Together, PTEN-inhibitor delivery via mesoporous nanocarriers can be considered a promising strategy for stimulating axonal regeneration in central and peripheral nervous systems. PMID:27386893

  13. 42 CFR 412.60 - DRG classification and weighting factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... DRG classification system provides a DRG, and an appropriate weighting factor, for the group of cases... 42 Public Health 2 2010-10-01 2010-10-01 false DRG classification and weighting factors. 412.60... Determining Prospective Payment Federal Rates for Inpatient Operating Costs § 412.60 DRG classification...

  14. GABA-CREB signalling regulates maturation and survival of newly generated neurons in the adult hippocampus

    PubMed Central

    Jagasia, Ravi; Steib, Kathrin; Englberger, Elisabeth; Herold, Sabine; Faus-Kessler, Theresa; Saxe, Michael; Gage, Fred H.; Song, Hongjun; Lie, D. Chichung

    2009-01-01

    Survival and integration of new neurons in the hippocampal circuit are rate-limiting steps in adult hippocampal neurogenesis. Neuronal network activity is a major regulator of these processes, yet little is known about the respective downstream signalling pathways. Here, we investigate the role of CREB signalling in adult hippocampal neurogenesis. CREB is activated in new granule neurons during a distinct developmental period. Loss of CREB function in a cell-autonomous fashion impairs dendritic development, decreases the expression of the neurogenic transcription factor NeuroD and of the neuronal microtubule associated protein, DCX, and compromises the survival of newborn neurons. In addition, GABA-mediated excitation regulates CREB activation at early developmental stages. Importantly, developmental defects following loss of GABA-mediated excitation can be compensated by enhanced CREB signalling. These results indicate that CREB signalling is a central pathway in adult hippocampal neurogenesis, regulating the development and survival of new hippocampal neurons downstream of GABA-mediated excitation. PMID:19553437

  15. The Role of Adult-Born Neurons in the Constantly Changing Olfactory Bulb Network

    PubMed Central

    Malvaut, Sarah; Saghatelyan, Armen

    2016-01-01

    The adult mammalian brain is remarkably plastic and constantly undergoes structurofunctional modifications in response to environmental stimuli. In many regions plasticity is manifested by modifications in the efficacy of existing synaptic connections or synapse formation and elimination. In a few regions, however, plasticity is brought by the addition of new neurons that integrate into established neuronal networks. This type of neuronal plasticity is particularly prominent in the olfactory bulb (OB) where thousands of neuronal progenitors are produced on a daily basis in the subventricular zone (SVZ) and migrate along the rostral migratory stream (RMS) towards the OB. In the OB, these neuronal precursors differentiate into local interneurons, mature, and functionally integrate into the bulbar network by establishing output synapses with principal neurons. Despite continuous progress, it is still not well understood how normal functioning of the OB is preserved in the constantly remodelling bulbar network and what role adult-born neurons play in odor behaviour. In this review we will discuss different levels of morphofunctional plasticity effected by adult-born neurons and their functional role in the adult OB and also highlight the possibility that different subpopulations of adult-born cells may fulfill distinct functions in the OB neuronal network and odor behaviour. PMID:26839709

  16. Expressing Constitutively Active Rheb in Adult Dorsal Root Ganglion Neurons Enhances the Integration of Sensory Axons that Regenerate Across a Chondroitinase-Treated Dorsal Root Entry Zone Following Dorsal Root Crush.

    PubMed

    Wu, Di; Klaw, Michelle C; Kholodilov, Nikolai; Burke, Robert E; Detloff, Megan R; Côté, Marie-Pascale; Tom, Veronica J

    2016-01-01

    While the peripheral branch of dorsal root ganglion neurons (DRG) can successfully regenerate after injury, lesioned central branch axons fail to regrow across the dorsal root entry zone (DREZ), the interface between the dorsal root and the spinal cord. This lack of regeneration is due to the limited regenerative capacity of adult sensory axons and the growth-inhibitory environment at the DREZ, which is similar to that found in the glial scar after a central nervous system (CNS) injury. We hypothesized that transduction of adult DRG neurons using adeno-associated virus (AAV) to express a constitutively-active form of the GTPase Rheb (caRheb) will increase their intrinsic growth potential after a dorsal root crush. Additionally, we posited that if we combined that approach with digestion of upregulated chondroitin sulfate proteoglycans (CSPG) at the DREZ with chondroitinase ABC (ChABC), we would promote regeneration of sensory axons across the DREZ into the spinal cord. We first assessed if this strategy promotes neuritic growth in an in vitro model of the glial scar containing CSPG. ChABC allowed for some regeneration across the once potently inhibitory substrate. Combining ChABC treatment with expression of caRheb in DRG significantly improved this growth. We then determined if this combination strategy also enhanced regeneration through the DREZ after dorsal root crush in adult rats in vivo. After unilaterally crushing C4-T1 dorsal roots, we injected AAV5-caRheb or AAV5-GFP into the ipsilateral C5-C8 DRGs. ChABC or PBS was injected into the ipsilateral dorsal horn at C5-C8 to digest CSPG, for a total of four animal groups (caRheb + ChABC, caRheb + PBS, GFP + ChABC, GFP + PBS). Regeneration was rarely observed in PBS-treated animals, whereas short-distance regrowth across the DREZ was observed in ChABC-treated animals. No difference in axon number or length between the ChABC groups was observed, which may be related to intraganglionic inflammation induced by the

  17. Expressing Constitutively Active Rheb in Adult Dorsal Root Ganglion Neurons Enhances the Integration of Sensory Axons that Regenerate Across a Chondroitinase-Treated Dorsal Root Entry Zone Following Dorsal Root Crush

    PubMed Central

    Wu, Di; Klaw, Michelle C.; Kholodilov, Nikolai; Burke, Robert E.; Detloff, Megan R.; Côté, Marie-Pascale; Tom, Veronica J.

    2016-01-01

    While the peripheral branch of dorsal root ganglion neurons (DRG) can successfully regenerate after injury, lesioned central branch axons fail to regrow across the dorsal root entry zone (DREZ), the interface between the dorsal root and the spinal cord. This lack of regeneration is due to the limited regenerative capacity of adult sensory axons and the growth-inhibitory environment at the DREZ, which is similar to that found in the glial scar after a central nervous system (CNS) injury. We hypothesized that transduction of adult DRG neurons using adeno-associated virus (AAV) to express a constitutively-active form of the GTPase Rheb (caRheb) will increase their intrinsic growth potential after a dorsal root crush. Additionally, we posited that if we combined that approach with digestion of upregulated chondroitin sulfate proteoglycans (CSPG) at the DREZ with chondroitinase ABC (ChABC), we would promote regeneration of sensory axons across the DREZ into the spinal cord. We first assessed if this strategy promotes neuritic growth in an in vitro model of the glial scar containing CSPG. ChABC allowed for some regeneration across the once potently inhibitory substrate. Combining ChABC treatment with expression of caRheb in DRG significantly improved this growth. We then determined if this combination strategy also enhanced regeneration through the DREZ after dorsal root crush in adult rats in vivo. After unilaterally crushing C4-T1 dorsal roots, we injected AAV5-caRheb or AAV5-GFP into the ipsilateral C5-C8 DRGs. ChABC or PBS was injected into the ipsilateral dorsal horn at C5-C8 to digest CSPG, for a total of four animal groups (caRheb + ChABC, caRheb + PBS, GFP + ChABC, GFP + PBS). Regeneration was rarely observed in PBS-treated animals, whereas short-distance regrowth across the DREZ was observed in ChABC-treated animals. No difference in axon number or length between the ChABC groups was observed, which may be related to intraganglionic inflammation induced by the

  18. Neurite formation by neurons derived from adult rat hippocampal progenitor cells is susceptible to myelin inhibition.

    PubMed

    Mellough, Carla B; Cho, Seongeun; Wood, Andrew; Przyborski, Stefan

    2011-09-01

    Myelin-associated inhibitors expressed following injury to the adult central nervous system (CNS) induce growth cone collapse and retraction of the axonal cytoskeleton. Myelin-associated glycoprotein (MAG) is a bi-functional molecule that promotes neuritogenesis in some immature neurons during development then becomes inhibitory to neurite outgrowth as neurons mature. Progress is being made towards the elucidation of the downstream events that regulate myelin inhibition of regeneration in neuronal populations. However it is not known how adult-derived neural stem cells or progenitors respond to myelin during neuronal differentiation and neuritogenesis. Here we examine the effect of MAG on neurons derived from an adult rat hippocampal progenitor cell line (AHPCs). We show that, unlike their developmental counterparts, AHPC-derived neurons are susceptible to MAG inhibition of neuritogenesis during differentiation and display a 57% reduction in neurite outgrowth when compared with controls. We demonstrate that this effect can be overcome (by up to 69%) by activation of the neurotrophin, cyclic AMP and protein kinase A pathways or by Rho-kinase suppression. We also demonstrate that combination of these factors enhanced neurite outgrowth from differentiating neurons in the presence of MAG. This work provides important information for the successful generation of new neurons from adult neural stem cell populations within compromised adult circuitry and is thus directly relevant to endogenous repair and regeneration of the adult CNS. PMID:21256909

  19. Cathepsin B-dependent motor neuron death after nerve injury in the adult mouse

    SciTech Connect

    Sun, Li; Wu, Zhou; Baba, Masashi; Peters, Christoph; Uchiyama, Yasuo; Nakanishi, Hiroshi

    2010-08-27

    Research highlights: {yields} Cathepsin B (CB), a lysosomal cysteine protease, is expressed in neuron and glia. {yields} CB increased in hypogrossal nucleus neurons after nerve injury in adult mice. {yields} CB-deficiency significantly increased the mean survival ratio of injured neurons. {yields} Thus, CB plays a critical role in axotomy-induced neuronal death in adult mice. -- Abstract: There are significant differences in the rate of neuronal death after peripheral nerve injury between species. The rate of neuronal death of motor neurons after nerve injury in the adult rats is very low, whereas that in adult mice is relatively high. However, the understanding of the mechanism underlying axotomy-induced motor neuron death in adult mice is limited. Cathepsin B (CB), a typical cysteine lysosomal protease, has been implicated in three major morphologically distinct pathways of cell death; apoptosis, necrosis and autophagic cell death. The possible involvement of CB in the neuronal death of hypogrossal nucleus (HGN) neurons after nerve injury in adult mice was thus examined. Quantitative analyses showed the mean survival ratio of HGN neurons in CB-deficient (CB-/-) adult mice after nerve injury was significantly greater than that in the wild-type mice. At the same time, proliferation of microglia in the injured side of the HGN of CB-/- adult mice was markedly reduced compared with that in the wild-type mice. On the injured side of the HGN in the wild-type adult mice, both pro- and mature forms of CB markedly increased in accordance with the increase in the membrane-bound form of LC3 (LC3-II), a marker protein of autophagy. Furthermore, the increase in CB preceded an increase in the expression of Noxa, a major executor for axotomy-induced motor neuron death in the adult mouse. Conversely, expression of neither Noxa or LC3-II was observed in the HGN of adult CB-/- mice after nerve injury. These observations strongly suggest that CB plays a critical role in axotomy

  20. TRIM32-dependent transcription in adult neural progenitor cells regulates neuronal differentiation.

    PubMed

    Hillje, A-L; Pavlou, M A S; Beckmann, E; Worlitzer, M M A; Bahnassawy, L; Lewejohann, L; Palm, T; Schwamborn, J C

    2013-01-01

    In the adult mammalian brain, neural stem cells in the subventricular zone continuously generate new neurons for the olfactory bulb. Cell fate commitment in these adult neural stem cells is regulated by cell fate-determining proteins. Here, we show that the cell fate-determinant TRIM32 is upregulated during differentiation of adult neural stem cells into olfactory bulb neurons. We further demonstrate that TRIM32 is necessary for the correct induction of neuronal differentiation in these cells. In the absence of TRIM32, neuroblasts differentiate slower and show gene expression profiles that are characteristic of immature cells. Interestingly, TRIM32 deficiency induces more neural progenitor cell proliferation and less cell death. Both effects accumulate in an overproduction of adult-generated olfactory bulb neurons of TRIM32 knockout mice. These results highlight the function of the cell fate-determinant TRIM32 for a balanced activity of the adult neurogenesis process. PMID:24357807

  1. Synaptic Integration of Adult-Born Hippocampal Neurons Is Locally Controlled by Astrocytes.

    PubMed

    Sultan, Sébastien; Li, Liyi; Moss, Jonathan; Petrelli, Francesco; Cassé, Frédéric; Gebara, Elias; Lopatar, Jan; Pfrieger, Frank W; Bezzi, Paola; Bischofberger, Josef; Toni, Nicolas

    2015-12-01

    Adult neurogenesis is regulated by the neurogenic niche, through mechanisms that remain poorly defined. Here, we investigated whether niche-constituting astrocytes influence the maturation of adult-born hippocampal neurons using two independent transgenic approaches to block vesicular release from astrocytes. In these models, adult-born neurons but not mature neurons showed reduced glutamatergic synaptic input and dendritic spine density that was accompanied with lower functional integration and cell survival. By taking advantage of the mosaic expression of transgenes in astrocytes, we found that spine density was reduced exclusively in segments intersecting blocked astrocytes, revealing an extrinsic, local control of spine formation. Defects in NMDA receptor (NMDAR)-mediated synaptic transmission and dendrite maturation were partially restored by exogenous D-serine, whose extracellular level was decreased in transgenic models. Together, these results reveal a critical role for adult astrocytes in local dendritic spine maturation, which is necessary for the NMDAR-dependent functional integration of newborn neurons. PMID:26606999

  2. Traumatic Brain Injury Causes Aberrant Migration of Adult-Born Neurons in the Hippocampus

    PubMed Central

    Ibrahim, Sara; Hu, Weipeng; Wang, Xiaoting; Gao, Xiang; He, Chunyan; Chen, Jinhui

    2016-01-01

    Traumatic brain injury (TBI) promotes neural stem/progenitor cell (NSC) proliferation in an attempt to initiate innate repair mechanisms. However, all immature neurons in the CNS are required to migrate from their birthplace to their final destination to develop into functional neurons. Here we assessed the destination of adult-born neurons following TBI. We found that a large percentage of immature neurons migrated past their normal stopping site at the inner granular cell layer (GCL), and became misplaced in the outer GCL of the hippocampal dentate gyrus. The aberrant migration of adult-born neurons in the hippocampus occurred 48 hours after TBI, and lasted for 8 weeks, resulting in a great number of newly generated neurons misplaced in the outer GCL in the hippocampus. Those misplaced neurons were able to become mature and differentiate into granular neurons, but located ectopically in the outer GCL with reduced dendritic complexity after TBI. The adult-born neurons at the misplaced position may make wrong connections with inappropriate nearby targets in the pre-existing neural network. These results suggest that although stimulation of endogenous NSCs following TBI might offer new avenues for cell-based therapy, additional intervention is required to further enhance successful neurogenesis for repairing the damaged brain. PMID:26898165

  3. Generation of New Neurons in Dorsal Root Ganglia in Adult Rats after Peripheral Nerve Crush Injury

    PubMed Central

    2015-01-01

    The evidence of neurons generated ex novo in sensory ganglia of adult animals is still debated. In the present study, we investigated, using high resolution light microscopy and stereological analysis, the changes in the number of neurons in dorsal root ganglia after 30 days from a crush lesion of the rat brachial plexus terminal branches. Results showed, as expected, a relevant hypertrophy of dorsal root ganglion neurons. In addition, we reported, for the first time in the literature, that neuronal hypertrophy was accompanied by massive neuronal hyperplasia leading to a 42% increase of the number of primary sensory neurons. Moreover, ultrastructural analyses on sensory neurons showed that there was not a relevant neuronal loss as a consequence of the nerve injury. The evidence of BrdU-immunopositive neurons and neural progenitors labeled with Ki67, nanog, nestin, and sox-2 confirmed the stereological evidence of posttraumatic neurogenesis in dorsal root ganglia. Analysis of morphological changes following axonal damage in addition to immunofluorescence characterization of cell phenotype suggested that the neuronal precursors which give rise to the newly generated neurons could be represented by satellite glial cells that actively proliferate after the lesion and are able to differentiate toward the neuronal lineage. PMID:25722894

  4. Distinct roles of hand2 in developing and adult autonomic neurons.

    PubMed

    Stanzel, Sabine; Stubbusch, Jutta; Pataskar, Abhijeet; Howard, Marthe J; Deller, Thomas; Ernsberger, Uwe; Tiwari, Vijay K; Rohrer, Hermann; Tsarovina, Konstantina

    2016-10-01

    The bHLH transcription factor Hand2 is essential for the acquisition and maintenance of noradrenergic properties of embryonic sympathetic neurons and controls neuroblast proliferation. Hand2 is also expressed in embryonic and postnatal parasympathetic ganglia and remains expressed in sympathetic neurons up to the adult stage. Here, we address its function in developing parasympathetic and adult sympathetic neurons. We conditionally deleted Hand2 in the parasympathetic sphenopalatine ganglion by crossing a line of floxed Hand2 mice with DbhiCre transgenic mice, taking advantage of the transient Dbh expression in parasympathetic ganglia. Hand2 elimination does not affect Dbh expression and sphenopalatine ganglion size at E12.5 and E16.5, in contrast to sympathetic ganglia. These findings demonstrate different functions for Hand2 in the parasympathetic and sympathetic lineage. Our previous Hand2 knockdown in postmitotic, differentiated chick sympathetic neurons resulted in decreased expression of noradrenergic marker genes but it was unclear whether Hand2 is required for maintaining noradrenergic neuron identity in adult animals. We now show that Hand2 elimination in adult Dbh-expressing sympathetic neurons does not decrease the expression of Th and Dbh, in contrast to the situation during development. However, gene expression profiling of adult sympathetic neurons identified 75 Hand2-dependent target genes. Interestingly, a notable proportion of down-regulated genes (15%) encode for proteins with synaptic and neurotransmission functions. These results demonstrate a change in Hand2 target genes during maturation of sympathetic neurons. Whereas Hand2 controls genes regulating noradrenergic differentiation during development, Hand2 seems to be involved in the regulation of genes controlling neurotransmission in adult sympathetic neurons. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1111-1124, 2016. PMID:26818017

  5. Genetic Methods to Identify and Manipulate Newly Born Neurons in the Adult Brain

    PubMed Central

    Imayoshi, Itaru; Sakamoto, Masayuki; Kageyama, Ryoichiro

    2011-01-01

    Although mammalian neurogenesis is mostly completed by the perinatal period, new neurons are continuously generated in the subventricular zone of the lateral ventricle and the subgranular zone of the hippocampal dentate gyrus. Since the discovery of adult neurogenesis, many extensive studies have been performed on various aspects of adult neurogenesis, including proliferation and fate-specification of adult neural stem cells, and the migration, maturation and synaptic integration of newly born neurons. Furthermore, recent research has shed light on the intensive contribution of adult neurogenesis to olfactory-related and hippocampus-mediated brain functions. The field of adult neurogenesis progressed tremendously thanks to technical advances that facilitate the identification and selective manipulation of newly born neurons among billions of pre-existing neurons in the adult central nervous system. In this review, we introduce recent advances in the methodologies for visualizing newly generated neurons and manipulating neurogenesis in the adult brain. Particularly, the application of site-specific recombinases and Tet inducible system in combination with transgenic or gene targeting strategy is discussed in further detail. PMID:21562606

  6. Heterogeneity of European DRG systems and potentials for a common EuroDRG system

    PubMed Central

    Geissler, Alexander; Quentin, Wilm; Busse, Reinhard

    2015-01-01

    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. PMID:25905484

  7. New neurons and new memories: how does adult hippocampal neurogenesis affect learning and memory?

    PubMed Central

    Deng, Wei; Aimone, James B.; Gage, Fred H.

    2010-01-01

    The integration of adult-born neurons into the circuitry of the adult hippocampus suggests an important role for adult hippocampal neurogenesis in learning and memory, but its specific function in these processes has remained elusive. In this article, we summarize recent progress in this area, including advances based on behavioural studies and insights provided by computational modelling. Increasingly, evidence suggests that newborn neurons might be involved in hippocampal functions that are particularly dependent on the dentate gyrus, such as pattern separation. Furthermore, newborn neurons at different maturation stages may make distinct contributions to learning and memory. In particular, computational studies suggest that, before newborn neurons are fully mature, they might function as a pattern integrator by introducing a degree of similarity to the encoding of events that occur closely in time. PMID:20354534

  8. Proliferating subventricular zone cells in the adult mammalian forebrain can differentiate into neurons and glia.

    PubMed Central

    Lois, C; Alvarez-Buylla, A

    1993-01-01

    Subventricular zone (SVZ) cells proliferate spontaneously in vivo in the telencephalon of adult mammals. Several studies suggest that SVZ cells do not differentiate after mitosis into neurons or glia but die. In the present work, we show that SVZ cells labeled in the brains of adult mice with [3H]thymidine differentiate directly into neurons and glia in explant cultures. In vitro labeling with [3H]thymidine shows that 98% of the neurons that differentiate from the SVZ explants are derived from precursor cells that underwent their last division in vivo. This report identifies the SVZ cells as neuronal precursors in an adult mammalian brain. Images Fig. 1 Fig. 2 Fig. 3 PMID:8446631

  9. A Sodium Leak Current Regulates Pacemaker Activity of Adult Central Pattern Generator Neurons in Lymnaea Stagnalis

    PubMed Central

    Lu, Tom Z.; Feng, Zhong-Ping

    2011-01-01

    The resting membrane potential of the pacemaker neurons is one of the essential mechanisms underlying rhythm generation. In this study, we described the biophysical properties of an uncharacterized channel (U-type channel) and investigated the role of the channel in the rhythmic activity of a respiratory pacemaker neuron and the respiratory behaviour in adult freshwater snail Lymnaea stagnalis. Our results show that the channel conducts an inward leak current carried by Na+ (ILeak-Na). The ILeak-Na contributed to the resting membrane potential and was required for maintaining rhythmic action potential bursting activity of the identified pacemaker RPeD1 neurons. Partial knockdown of the U-type channel suppressed the aerial respiratory behaviour of the adult snail in vivo. These findings identified the Na+ leak conductance via the U-type channel, likely a NALCN-like channel, as one of the fundamental mechanisms regulating rhythm activity of pacemaker neurons and respiratory behaviour in adult animals. PMID:21526173

  10. Id2 IS REQUIRED FOR SPECIFICATION OF DOPAMINERGIC NEURONS DURING ADULT OLFACTORY NEUROGENESIS

    PubMed Central

    Havrda, Matthew C.; Harris, Brent T.; Mantani, Akio; Ward, Nora M.; Paolella, Brenton R.; Cuzon, Verginia C.; Yeh, Hermes H.; Israel, Mark A.

    2009-01-01

    Understanding the biology of adult neural stem cells has important implications for nervous system development and may contribute to our understanding of neurodegenerative disorders and their treatment. We have characterized the process of olfactory neurogenesis in adult mice lacking Inhibitor of DNA Binding 2 (Id2). We found a diminished olfactory bulb containing reduced numbers of granular and periglomerular neurons with a distinct paucity of dopaminergic periglomerular neurons. While no deficiency of the stem cell compartment was detectable, migrating neuroblasts in Id2−/− mutant mice prematurely undergo astroglial differentiation within a disorganized rostral migratory stream. Further, when evaluated in vitro loss of Id2 results in decreased proliferation of neural progenitors and decreased expression of the Hes1 and Mash1 transcription factors, known mediators of neuronal differentiation. These data support a novel role for sustained Id2 expression in migrating neural progenitors mediating olfactory dopaminergic neuronal differentiation in adult animals. PMID:19109490

  11. Zebrafish adult-derived hypothalamic neurospheres generate gonadotropin-releasing hormone (GnRH) neurons.

    PubMed

    Cortés-Campos, Christian; Letelier, Joaquín; Ceriani, Ricardo; Whitlock, Kathleen E

    2015-01-01

    Gonadotropin-releasing hormone (GnRH) is a hypothalamic decapeptide essential for fertility in vertebrates. Human male patients lacking GnRH and treated with hormone therapy can remain fertile after cessation of treatment suggesting that new GnRH neurons can be generated during adult life. We used zebrafish to investigate the neurogenic potential of the adult hypothalamus. Previously we have characterized the development of GnRH cells in the zebrafish linking genetic pathways to the differentiation of neuromodulatory and endocrine GnRH cells in specific regions of the brain. Here, we developed a new method to obtain neural progenitors from the adult hypothalamus in vitro. Using this system, we show that neurospheres derived from the adult hypothalamus can be maintained in culture and subsequently differentiate glia and neurons. Importantly, the adult derived progenitors differentiate into neurons containing GnRH and the number of cells is increased through exposure to either testosterone or GnRH, hormones used in therapeutic treatment in humans. Finally, we show in vivo that a neurogenic niche in the hypothalamus contains GnRH positive neurons. Thus, we demonstrated for the first time that neurospheres can be derived from the hypothalamus of the adult zebrafish and that these neural progenitors are capable of producing GnRH containing neurons. PMID:26209533

  12. Zebrafish adult-derived hypothalamic neurospheres generate gonadotropin-releasing hormone (GnRH) neurons

    PubMed Central

    Cortés-Campos, Christian; Letelier, Joaquín; Ceriani, Ricardo; Whitlock, Kathleen E.

    2015-01-01

    ABSTRACT Gonadotropin-releasing hormone (GnRH) is a hypothalamic decapeptide essential for fertility in vertebrates. Human male patients lacking GnRH and treated with hormone therapy can remain fertile after cessation of treatment suggesting that new GnRH neurons can be generated during adult life. We used zebrafish to investigate the neurogenic potential of the adult hypothalamus. Previously we have characterized the development of GnRH cells in the zebrafish linking genetic pathways to the differentiation of neuromodulatory and endocrine GnRH cells in specific regions of the brain. Here, we developed a new method to obtain neural progenitors from the adult hypothalamus in vitro. Using this system, we show that neurospheres derived from the adult hypothalamus can be maintained in culture and subsequently differentiate glia and neurons. Importantly, the adult derived progenitors differentiate into neurons containing GnRH and the number of cells is increased through exposure to either testosterone or GnRH, hormones used in therapeutic treatment in humans. Finally, we show in vivo that a neurogenic niche in the hypothalamus contains GnRH positive neurons. Thus, we demonstrated for the first time that neurospheres can be derived from the hypothalamus of the adult zebrafish and that these neural progenitors are capable of producing GnRH containing neurons. PMID:26209533

  13. Adult axolotls can regenerate original neuronal diversity in response to brain injury.

    PubMed

    Amamoto, Ryoji; Huerta, Violeta Gisselle Lopez; Takahashi, Emi; Dai, Guangping; Grant, Aaron K; Fu, Zhanyan; Arlotta, Paola

    2016-01-01

    The axolotl can regenerate multiple organs, including the brain. It remains, however, unclear whether neuronal diversity, intricate tissue architecture, and axonal connectivity can be regenerated; yet, this is critical for recovery of function and a central aim of cell replacement strategies in the mammalian central nervous system. Here, we demonstrate that, upon mechanical injury to the adult pallium, axolotls can regenerate several of the populations of neurons present before injury. Notably, regenerated neurons acquire functional electrophysiological traits and respond appropriately to afferent inputs. Despite the ability to regenerate specific, molecularly-defined neuronal subtypes, we also uncovered previously unappreciated limitations by showing that newborn neurons organize within altered tissue architecture and fail to re-establish the long-distance axonal tracts and circuit physiology present before injury. The data provide a direct demonstration that diverse, electrophysiologically functional neurons can be regenerated in axolotls, but challenge prior assumptions of functional brain repair in regenerative species. PMID:27156560

  14. Extracellular Nm23H1 stimulates neurite outgrowth from dorsal root ganglia neurons in vitro independently of nerve growth factor supplementation or its nucleoside diphosphate kinase activity

    SciTech Connect

    Wright, K.T.; Seabright, R.; Logan, A.; Lilly, A.J.; Khanim, F.; Bunce, C.M.; Johnson, W.E.B.

    2010-07-16

    Research highlights: {yields} Extracellular Nm23H1 stimulates nerve growth. {yields} Extracellular Nm23H1 provides pathfinding cues to growth cones. {yields} The neurotrophic activity of Nm23H1 is independent of NDP kinase activity. {yields} The neurotrophic activity of Nm23H1 is independent of NGF. -- Abstract: The nucleoside diphosphate (NDP) kinase, Nm23H1, is a highly expressed during neuronal development, whilst induced over-expression in neuronal cells results in increased neurite outgrowth. Extracellular Nm23H1 affects the survival, proliferation and differentiation of non-neuronal cells. Therefore, this study has examined whether extracellular Nm23H1 regulates nerve growth. We have immobilised recombinant Nm23H1 proteins to defined locations of culture plates, which were then seeded with explants of embryonic chick dorsal root ganglia (DRG) or dissociated adult rat DRG neurons. The substratum-bound extracellular Nm23H1 was stimulatory for neurite outgrowth from chick DRG explants in a concentration-dependent manner. On high concentrations of Nm23H1, chick DRG neurite outgrowth was extensive and effectively limited to the location of the Nm23H1, i.e. neuronal growth cones turned away from adjacent collagen-coated substrata. Nm23H1-coated substrata also significantly enhanced rat DRG neuronal cell adhesion and neurite outgrowth in comparison to collagen-coated substrata. These effects were independent of NGF supplementation. Recombinant Nm23H1 (H118F), which does not possess NDP kinase activity, exhibited the same activity as the wild-type protein. Hence, a novel neuro-stimulatory activity for extracellular Nm23H1 has been identified in vitro, which may function in developing neuronal systems.

  15. Div-Seq: Single-nucleus RNA-Seq reveals dynamics of rare adult newborn neurons.

    PubMed

    Habib, Naomi; Li, Yinqing; Heidenreich, Matthias; Swiech, Lukasz; Avraham-Davidi, Inbal; Trombetta, John J; Hession, Cynthia; Zhang, Feng; Regev, Aviv

    2016-08-26

    Single-cell RNA sequencing (RNA-Seq) provides rich information about cell types and states. However, it is difficult to capture rare dynamic processes, such as adult neurogenesis, because isolation of rare neurons from adult tissue is challenging and markers for each phase are limited. Here, we develop Div-Seq, which combines scalable single-nucleus RNA-Seq (sNuc-Seq) with pulse labeling of proliferating cells by 5-ethynyl-2'-deoxyuridine (EdU) to profile individual dividing cells. sNuc-Seq and Div-Seq can sensitively identify closely related hippocampal cell types and track transcriptional dynamics of newborn neurons within the adult hippocampal neurogenic niche, respectively. We also apply Div-Seq to identify and profile rare newborn neurons in the adult spinal cord, a noncanonical neurogenic region. sNuc-Seq and Div-Seq open the way for unbiased analysis of diverse complex tissues. PMID:27471252

  16. Adult-born dentate neurons are recruited in both spatial memory encoding and retrieval.

    PubMed

    Tronel, Sophie; Charrier, Vanessa; Sage, Cyrille; Maitre, Marlene; Leste-Lasserre, Thierry; Abrous, Djoher N

    2015-11-01

    Adult neurogenesis occurs in the dentate gyrus (DG) of the hippocampus, which is a key structure in learning and memory. Adult-generated granule cells have been shown to play a role in spatial memory processes such as acquisition or retrieval, in particular during an immature stage when they exhibit a period of increased plasticity. Here, we demonstrate that immature and mature neurons born in the DG of adult rats are similarly activated in spatial memory processes. By imaging the activation of these two different neuron generations in the same rat and by using the immediate early gene Zif268, we show that these neurons are involved in both spatial memory acquisition and retrieval. These results demonstrate that adult-generated granule cells are involved in memory beyond their immaturity stage. PMID:25913775

  17. Direct Differentiation of Adult Ocular Progenitors into Striatal Dopaminergic Neurons

    PubMed Central

    Ahmad, Iqbal; Zhao, Xing; Parameswaran, Sowmya; Destache, Christopher J.; Rodriguez-Sierra, Jorge; Thoreson, Wallace B.; Ahmad, Hiba; Sorrentino, John; Balasubramanian, Sudha

    2015-01-01

    Parkinson’s disease, characterized by motor dysfunction due to the loss of nigrostriatal dopaminergic neurons, is one of the most prevalent age-related neurodegenerative disorders. Given there is no current cure, the stem cell approach has emerged as a viable therapeutic option to replace the dopaminergic neurons that are progressively lost to the disease. The success of the approach is likely to depend upon accessible, renewable, immune compatible, and non-tumorigenic sources of neural progenitors from which stable dopaminergic neurons can be generated efficaciously. Here, we demonstrate that neural progenitors derived from limbus, a regenerative and accessible ocular tissue, represent a safe source of dopaminergic neurons. When the limbus-derived neural progenitors were subjected to a well-established protocol of directed differentiation under the influence of Shh and FGF8, they acquired the biochemical and functional phenotype of dopaminergic neurons that included the ability to synthesize dopamine. Their intrastriatal transplantation in the rat model of hemi-Parkinsonism was associated with a reduction in the amphetamine-induced rotation. No tumor formation was observed 6 weeks post-transplantation. Together, these observations posit limbus-derived neural progenitors as an accessible and safe source of dopaminergic neurons for a potential autologous ex-vivo stem cell approach to Parkinson’s disease. PMID:26019760

  18. Direct differentiation of adult ocular progenitors into striatal dopaminergic neurons.

    PubMed

    Ahmad, Iqbal; Zhao, Xing; Parameswaran, Sowmya; Destache, Christopher J; Rodriguez-Sierra, Jorge; Thoreson, Wallace B; Ahmad, Hiba; Sorrentino, John; Balasubramanian, Sudha

    2015-05-01

    Parkinson's disease, characterized by motor dysfunction due to the loss of nigrostriatal dopaminergic neurons, is one of the most prevalent age-related neurodegenerative disorders. Given there is no current cure, the stem cell approach has emerged as a viable therapeutic option to replace the dopaminergic neurons that are progressively lost to the disease. The success of the approach is likely to depend upon accessible, renewable, immune compatible, and non-tumorigenic sources of neural progenitors from which stable dopaminergic neurons can be generated efficaciously. Here, we demonstrate that neural progenitors derived from limbus, a regenerative and accessible ocular tissue, represent a safe source of dopaminergic neurons. When the limbus-derived neural progenitors were subjected to a well-established protocol of directed differentiation under the influence of Shh and FGF8, they acquired the biochemical and functional phenotype of dopaminergic neurons that included the ability to synthesize dopamine. Their intrastriatal transplantation in the rat model of hemi-Parkinsonism was associated with a reduction in the amphetamine-induced rotation. No tumor formation was observed 6 weeks post-transplantation. Together, these observations posit limbus-derived neural progenitors as an accessible and safe source of dopaminergic neurons for a potential autologous ex-vivo stem cell approach to Parkinson's disease. PMID:26019760

  19. Selective Viral Transduction of Adult-born Olfactory Neurons for Chronic in vivo Optogenetic Stimulation

    PubMed Central

    Lepousez, Gabriel; Alonso, Mariana; Wagner, Sebastian; Gallarda, Benjamin W.; Lledo, Pierre-Marie

    2011-01-01

    Local interneurons are continuously regenerated in the olfactory bulb of adult rodents1-3. In this process, called adult neurogenesis, neural stem cells in the walls of the lateral ventricle give rise to neuroblasts that migrate for several millimeters along the rostral migratory stream (RMS) to reach and incorporate into the olfactory bulb. To study the different steps and the impact of adult-born neuron integration into preexisting olfactory circuits, it is necessary to selectively label and manipulate the activity of this specific population of neurons. The recent development of optogenetic technologies offers the opportunity to use light to precisely activate this specific cohort of neurons without affecting surrounding neurons4,5. Here, we present a series of procedures to virally express Channelrhodopsin2(ChR2)-YFP in a temporally restricted cohort of neuroblasts in the RMS before they reach the olfactory bulb and become adult-born neurons. In addition, we show how to implant and calibrate a miniature LED for chronic in vivo stimulation of ChR2-expressing neurons. PMID:22231709

  20. Respiratory neuron characterization reveals intrinsic bursting properties in isolated adult turtle brainstems (Trachemys scripta).

    PubMed

    Johnson, Stephen M; Hedrick, Michael S; Krause, Bryan M; Nilles, Jacob P; Chapman, Mark A

    2016-04-01

    It is not known whether respiratory neurons with intrinsic bursting properties exist within ectothermic vertebrate respiratory control systems. Thus, isolated adult turtle brainstems spontaneously producing respiratory motor output were used to identify and classify respiratory neurons based on their firing pattern relative to hypoglossal (XII) nerve activity. Most respiratory neurons (183/212) had peak activity during the expiratory phase, while inspiratory, post-inspiratory, and novel pre-expiratory neurons were less common. During synaptic blockade conditions, ∼10% of respiratory neurons fired bursts of action potentials, with post-inspiratory cells (6/9) having the highest percentage of intrinsic burst properties. Most intrinsically bursting respiratory neurons were clustered at the level of the vagus (X) nerve root. Synaptic inhibition blockade caused seizure-like activity throughout the turtle brainstem, which shows that the turtle respiratory control system is not transformed into a network driven by intrinsically bursting respiratory neurons. We hypothesize that intrinsically bursting respiratory neurons are evolutionarily conserved and represent a potential rhythmogenic mechanism contributing to respiration in adult turtles. PMID:25462012

  1. Immature spinal cord neurons are dynamic regulators of adult nociceptive sensitivity

    PubMed Central

    Rusanescu, Gabriel; Mao, Jianren

    2015-01-01

    Chronic pain is a debilitating condition with unknown mechanism. Nociceptive sensitivity may be regulated by genetic factors, some of which have been separately linked to neuronal progenitor cells and neuronal differentiation. This suggests that genetic factors that interfere with neuronal differentiation may contribute to a chronic increase in nociceptive sensitivity, by extending the immature, hyperexcitable stage of spinal cord neurons. Although adult rodent spinal cord neurogenesis was previously demonstrated, the fate of these progenitor cells is unknown. Here, we show that peripheral nerve injury in adult rats induces extensive spinal cord neurogenesis and a long-term increase in the number of spinal cord laminae I–II neurons ipsilateral to injury. The production and maturation of these new neurons correlates with the time course and modulation of nociceptive behaviour, and transiently mimics the cellular and behavioural conditions present in genetically modified animal models of chronic pain. This suggests that the number of immature neurons present at any time in the spinal cord dorsal horns contributes to the regulation of nociceptive sensitivity. The continuous turnover of these neurons, which can fluctuate between normal and injured states, is a dynamic regulator of nociceptive sensitivity. In support of this hypothesis, we find that promoters of neuronal differentiation inhibit, while promoters of neurogenesis increase long-term nociception. TrkB agonists, well-known promoters of nociception in the short-term, significantly inhibit long-term nociception by promoting the differentiation of newly produced immature neurons. These findings suggest that promoters of neuronal differentiation may be used to alleviate chronic pain. PMID:26223362

  2. Phosphoinositide signaling in somatosensory neurons.

    PubMed

    Rohacs, Tibor

    2016-05-01

    Somatosensory neurons of the dorsal root ganglia (DRG) and trigeminal ganglia (TG) are responsible for detecting thermal and tactile stimuli. They are also the primary neurons mediating pain and itch. A large number of cell surface receptors in these neurons couple to phospholipase C (PLC) enzymes leading to the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the generation of downstream signaling molecules. These neurons also express many different ion channels, several of which are regulated by phosphoinositides. This review will summarize the knowledge on phosphoinositide signaling in DRG neurons, with special focus on effects on sensory and other ion channels. PMID:26724974

  3. In Vitro Functional Assessment of Adult Spiral Ganglion Neurons (SGNs).

    PubMed

    Lee, Jeong Han; Sihn, Choongryoul; Wang, Wanging; Flores, Cristina Maria Perez; Yamoah, Ebenezer N

    2016-01-01

    Spiral ganglion neurons (SGNs) faithfully encode acoustic waves from hair cells to the cochlear nucleus (CN) using voltage-dependent ion channels. A sizable portion of our knowledge on SGN functions have been derived from pre-hearing neurons. In post-hearing SGNs, the mechanisms of how they encode the massive sound information without delay and precisely are largely unknown. Mature SGNs are housed in the central bony labyrinth of the cochlea, protected by a well-insulated myelin sheath, making it a technical feat to isolate viable neurons for rigorous functional electrophysiology. Recently, we have overcome the previous intractable hindrance in SGN functional analyses. We provide a step-by-step user-friendly protocol with practical applications, including patch-clamp recordings and imaging by using cultured SGNs. PMID:27259946

  4. Specification of individual adult motor neuron morphologies by combinatorial transcription factor codes

    PubMed Central

    Enriquez, Jonathan; Venkatasubramanian, Lalanti; Baek, Myungin; Peterson, Meredith; Aghayeva, Ulkar; Mann, Richard S.

    2015-01-01

    Summary How the highly stereotyped morphologies of individual neurons are genetically specified is not well understood. We identify six transcription factors (TFs) expressed in a combinatorial manner in seven post-mitotic adult leg motor neurons (MNs) that are derived from a single neuroblast in Drosophila. Unlike TFs expressed in mitotically active neuroblasts, these TFs do not regulate each other's expression. Removing the activity of a single TF resulted in specific morphological defects, including muscle targeting and dendritic arborization, and in a highly specific walking defect in adult flies. In contrast, when the expression of multiple TFs was modified nearly complete transformations in MN morphologies were generated. These results show that the morphological characteristics of a single neuron are dictated by a combinatorial code of morphology TFs (mTFs). mTFs function at a previously unidentified regulatory tier downstream of factors acting in the NB, but independently of factors that act in terminally differentiated neurons. PMID:25959734

  5. Thalamocortical Projections onto Behaviorally Relevant Neurons Exhibit Plasticity during Adult Motor Learning.

    PubMed

    Biane, Jeremy S; Takashima, Yoshio; Scanziani, Massimo; Conner, James M; Tuszynski, Mark H

    2016-03-16

    Layer 5 neurons of the neocortex receive direct and relatively strong input from the thalamus. However, the intralaminar distribution of these inputs and their capacity for plasticity in adult animals are largely unknown. In slices of the primary motor cortex (M1), we simultaneously recorded from pairs of corticospinal neurons associated with control of distinct motor outputs: distal forelimb versus proximal forelimb. Activation of ChR2-expressing thalamocortical afferents in M1 before motor learning produced equivalent responses in monosynaptic excitation of neurons controlling the distal and proximal forelimb, suggesting balanced thalamic input at baseline. Following skilled grasp training, however, thalamocortical input shifted to bias activation of corticospinal neurons associated with control of the distal forelimb. This increase was associated with a cell-specific increase in mEPSC amplitude but not presynaptic release probability. These findings demonstrate distinct and highly segregated plasticity of thalamocortical projections during adult learning. PMID:26948893

  6. Extensive Neuronal Differentiation of Human Neural Stem Cell Grafts in Adult Rat Spinal Cord

    PubMed Central

    Yan, Jun; Xu, Leyan; Welsh, Annie M; Hatfield, Glen; Hazel, Thomas; Johe, Karl; Koliatsos, Vassilis E

    2007-01-01

    Background Effective treatments for degenerative and traumatic diseases of the nervous system are not currently available. The support or replacement of injured neurons with neural grafts, already an established approach in experimental therapeutics, has been recently invigorated with the addition of neural and embryonic stem-derived precursors as inexhaustible, self-propagating alternatives to fetal tissues. The adult spinal cord, i.e., the site of common devastating injuries and motor neuron disease, has been an especially challenging target for stem cell therapies. In most cases, neural stem cell (NSC) transplants have shown either poor differentiation or a preferential choice of glial lineages. Methods and Findings In the present investigation, we grafted NSCs from human fetal spinal cord grown in monolayer into the lumbar cord of normal or injured adult nude rats and observed large-scale differentiation of these cells into neurons that formed axons and synapses and established extensive contacts with host motor neurons. Spinal cord microenvironment appeared to influence fate choice, with centrally located cells taking on a predominant neuronal path, and cells located under the pia membrane persisting as NSCs or presenting with astrocytic phenotypes. Slightly fewer than one-tenth of grafted neurons differentiated into oligodendrocytes. The presence of lesions increased the frequency of astrocytic phenotypes in the white matter. Conclusions NSC grafts can show substantial neuronal differentiation in the normal and injured adult spinal cord with good potential of integration into host neural circuits. In view of recent similar findings from other laboratories, the extent of neuronal differentiation observed here disputes the notion of a spinal cord that is constitutively unfavorable to neuronal repair. Restoration of spinal cord circuitry in traumatic and degenerative diseases may be more realistic than previously thought, although major challenges remain

  7. Assigning Function to Adult-Born Neurons: A Theoretical Framework for Characterizing Neural Manipulation of Learning

    PubMed Central

    Hersman, Sarah; Rodriguez Barrera, Vanessa; Fanselow, Michael

    2016-01-01

    Neuroscientists are concerned with neural processes or computations, but these may not be directly observable. In the field of learning, a behavioral procedure is observed to lead to performance outcomes, but differing inferences on underlying internal processes can lead to difficulties in interpreting conflicting results. An example of this challenge is how many functions have been attributed to adult-born granule cells in the dentate gyrus. Some of these functions were suggested by computational models of the properties of these neurons, while others were hypothesized after manipulations of adult-born neurons resulted in changes to behavioral metrics. This review seeks to provide a framework, based in learning theory classification of behavioral procedures, of the processes that may be underlying behavioral results after manipulating procedure and observing performance. We propose that this framework can serve to clarify experimental findings on adult-born neurons as well as other classes of neural manipulations and their effects on behavior. PMID:26778981

  8. Acute Effects of Transforming Growth Factor-β1 on Neuronal Excitability and Involvement in the Pain of Rats with Chronic Pancreatitis

    PubMed Central

    Zhang, Xiaoyu; Zheng, Hang; Zhu, Hong-Yan; Hu, Shufen; Wang, Shusheng; Jiang, Xinghong; Xu, Guang-Yin

    2016-01-01

    Background/Aims This study was to investigate whether transforming growth factor-β1 (TGF-β1) plays a role in hyperalgesia in chronic pancreatitis (CP) and the underlying mechanisms. Methods CP was induced in male adult rats by intraductal injection of trinitrobenzene sulfonic acid (TNBS). Abdominal hyperalgesia was assessed by referred somatic behaviors to mechanical stimulation of rat abdomen. Dil dye injected into the pancreas was used to label pancreas-specific dorsal root ganglion (DRG) neurons. Whole cell patch clamp recordings and calcium imaging were performed to examine the effect of TGF-β1 on acutely isolated pancreas-specific DRG neurons. Western blot analysis was carried out to measure the expression of TGF-β1 and its receptors. Results TNBS injection significantly upregulated expression of TGF-β1 in the pancreas and DRGs, and TGF-β1 receptors in DRGs (T9-T13) in CP rats. Intrathecal injection of TGF-β receptor I antagonist SB431542 attenuated abdominal hyperalgesia in CP rats. TGF-β1 application depolarized the membrane potential and caused firing activity of DRG neurons. TGF-β1 application also reduced rheobase, hyperpolarized action potential threshold, and increased numbers of action potentials evoked by current injection of pancreas-specific DRG neurons. TGF-β1 application also increased the concentration of intracellular calcium of DRG neurons, which was inhibited by SB431542. Furthermore, intrathecal injection of TGF-β1 produced abdominal hyperalgesia in healthy rats. Conclusions These results suggest that TGF-β1 enhances neuronal excitability and increases the concentration of intracellular calcium. TGF-β1 and its receptors are involved in abdominal hyperalgesia in CP. This and future study might identify a potentially novel target for the treatment of abdominal pain in CP. PMID:26645248

  9. Neurons diversify astrocytes in the adult brain through sonic hedgehog signaling.

    PubMed

    Farmer, W Todd; Abrahamsson, Therése; Chierzi, Sabrina; Lui, Christopher; Zaelzer, Cristian; Jones, Emma V; Bally, Blandine Ponroy; Chen, Gary G; Théroux, Jean-Francois; Peng, Jimmy; Bourque, Charles W; Charron, Frédéric; Ernst, Carl; Sjöström, P Jesper; Murai, Keith K

    2016-02-19

    Astrocytes are specialized and heterogeneous cells that contribute to central nervous system function and homeostasis. However, the mechanisms that create and maintain differences among astrocytes and allow them to fulfill particular physiological roles remain poorly defined. We reveal that neurons actively determine the features of astrocytes in the healthy adult brain and define a role for neuron-derived sonic hedgehog (Shh) in regulating the molecular and functional profile of astrocytes. Thus, the molecular and physiological program of astrocytes is not hardwired during development but, rather, depends on cues from neurons that drive and sustain their specialized properties. PMID:26912893

  10. The Transcription Repressor REST in Adult Neurons: Physiology, Pathology, and Diseases1,2,3

    PubMed Central

    Baldelli, Pietro

    2015-01-01

    Abstract REST [RE1-silencing transcription factor (also called neuron-restrictive silencer factor)] is known to repress thousands of possible target genes, many of which are neuron specific. To date, REST repression has been investigated mostly in stem cells and differentiating neurons. Current evidence demonstrates its importance in adult neurons as well. Low levels of REST, which are acquired during differentiation, govern the expression of specific neuronal phenotypes. REST-dependent genes encode important targets, including transcription factors, transmitter release proteins, voltage-dependent and receptor channels, and signaling proteins. Additional neuronal properties depend on miRNAs expressed reciprocally to REST and on specific splicing factors. In adult neurons, REST levels are not always low. Increases occur during aging in healthy humans. Moreover, extensive evidence demonstrates that prolonged stimulation with various agents induces REST increases, which are associated with the repression of neuron-specific genes with appropriate, intermediate REST binding affinity. Whether neuronal increases in REST are protective or detrimental remains a subject of debate. Examples of CA1 hippocampal neuron protection upon depolarization, and of neurodegeneration upon glutamate treatment and hypoxia have been reported. REST participation in psychiatric and neurological diseases has been shown, especially in Alzheimer’s disease and Huntington’s disease, as well as epilepsy. Distinct, complex roles of the repressor in these different diseases have emerged. In conclusion, REST is certainly very important in a large number of conditions. We suggest that the conflicting results reported for the role of REST in physiology, pathology, and disease depend on its complex, direct, and indirect actions on many gene targets and on the diverse approaches used during the investigations. PMID:26465007

  11. [Regulation of neurogenesis: factors affecting of new neurons formation in adult mammals brain].

    PubMed

    Respondek, Michalina; Buszman, Ewa

    2015-01-01

    Neurogenesis is a complex and multi-step process of generating completely functional neurons. This process in adult brain is based on pluripotentional neuronal stem cells (NSC), which are able to proliferation and differentiation into mature neurons or glial cells. NSC are located in subgranular zone inside hippocampus and in subventricular zone. The new neurons formation depends on many endo- and exogenous factors which modulate each step of neurogenesis. This article describes the most important regulators of adult neurogenesis, mainly: neurotrophins, growth factors, hormones, neurotransmitters and microenvironment of NSC. Some drugs, especially antipsychotics, antidepressants and normothymics may affect the neurogenic properties of adult brain. Moreover pathological processes such as neuroinflammation, stroke or epilepsy are able to induce proliferation of NSC. The proneurogenic effects of psychotropic drugs and pathological processes are associated with their ability to increase some hormones and neurotrophins level, as well as with rising the expression of antiapoptotic Bcl-2 protein and metalloproteinase MMP-2. Additionaly, some drugs, for example haloperidol, are able to block prolactin and dopaminergic neuroblasts receptors. Down-regulation of adult neurogenesis is associated with alcohol abuse and high stress level. Negative effect of many drugs, such as cytostatics, COX-2 inhibitors and opioides was also observed. The proneurogenic effect of described factors suggest their broad therapeutic potential and gives a new perspective on an effective and modern treatment of many neuropsychiatric disorders. This effect can also help to clarify the pathogenesis of disorders associated with proliferation and degeneration of adult brain cells. PMID:27259217

  12. Synaptic dysfunction, memory deficits and hippocampal atrophy due to ablation of mitochondrial fission in adult forebrain neurons

    PubMed Central

    Oettinghaus, B; Schulz, J M; Restelli, L M; Licci, M; Savoia, C; Schmidt, A; Schmitt, K; Grimm, A; Morè, L; Hench, J; Tolnay, M; Eckert, A; D'Adamo, P; Franken, P; Ishihara, N; Mihara, K; Bischofberger, J; Scorrano, L; Frank, S

    2016-01-01

    Well-balanced mitochondrial fission and fusion processes are essential for nervous system development. Loss of function of the main mitochondrial fission mediator, dynamin-related protein 1 (Drp1), is lethal early during embryonic development or around birth, but the role of mitochondrial fission in adult neurons remains unclear. Here we show that inducible Drp1 ablation in neurons of the adult mouse forebrain results in progressive, neuronal subtype-specific alterations of mitochondrial morphology in the hippocampus that are marginally responsive to antioxidant treatment. Furthermore, DRP1 loss affects synaptic transmission and memory function. Although these changes culminate in hippocampal atrophy, they are not sufficient to cause neuronal cell death within 10 weeks of genetic Drp1 ablation. Collectively, our in vivo observations clarify the role of mitochondrial fission in neurons, demonstrating that Drp1 ablation in adult forebrain neurons compromises critical neuronal functions without causing overt neurodegeneration. PMID:25909888

  13. Parvalbumin interneurons mediate neuronal circuitry-neurogenesis coupling in the adult hippocampus

    PubMed Central

    Song, Juan; Sun, Jiaqi; Moss, Jonathan; Wen, Zhexing; Sun, Gerald J.; Hsu, Derek; Zhong, Chun; Davoudi, Heydar; Christian, Kimberly M.; Toni, Nicolas; Ming, Guo-li; Song, Hongjun

    2014-01-01

    Using immunohistology, electron microscopy, electrophysiology and optogenetics, we show that proliferating adult hippocampal neural precursors receive immature GABAergic synaptic inputs from parvalbumin-expressing interneurons. Recently shown to suppress quiescent neural stem cell activation, parvalbumin interneuron activation promotes newborn neuronal progeny survival and development. Our study suggests a niche mechanism involving parvalbumin interneurons that couples local circuit activity to diametric regulation of two critical initial phases of adult hippocampal neurogenesis. PMID:24212671

  14. Development and Maturation of Embryonic Cortical Neurons Grafted into the Damaged Adult Motor Cortex

    PubMed Central

    Ballout, Nissrine; Frappé, Isabelle; Péron, Sophie; Jaber, Mohamed; Zibara, Kazem; Gaillard, Afsaneh

    2016-01-01

    Injury to the human central nervous system can lead to devastating consequences due to its poor ability to self-repair. Neural transplantation aimed at replacing lost neurons and restore functional circuitry has proven to be a promising therapeutical avenue. We previously reported in adult rodent animal models with cortical lesions that grafted fetal cortical neurons could effectively re-establish specific patterns of projections and synapses. The current study was designed to provide a detailed characterization of the spatio-temporal in vivo development of fetal cortical transplanted cells within the lesioned adult motor cortex and their corresponding axonal projections. We show here that as early as 2 weeks after grafting, cortical neuroblasts transplanted into damaged adult motor cortex developed appropriate projections to cortical and subcortical targets. Grafted cells initially exhibited characteristics of immature neurons, which then differentiated into mature neurons with appropriate cortical phenotypes where most were glutamatergic and few were GABAergic. All cortical subtypes identified with the specific markers CTIP2, Cux1, FOXP2, and Tbr1 were generated after grafting as evidenced with BrdU co-labeling. The set of data provided here is of interest as it sets biological standards for future studies aimed at replacing fetal cells with embryonic stem cells as a source of cortical neurons. PMID:27536221

  15. Arginine vasotocin neuronal development and its projection in the adult brain of the medaka.

    PubMed

    Kagawa, Nao; Honda, Akira; Zenno, Akiko; Omoto, Ryosuke; Imanaka, Saya; Takehana, Yusuke; Naruse, Kiyoshi

    2016-02-01

    The neurohypophysial peptide arginine vasotocin (AVT) and its mammalian ortholog arginine vasopressin function in a wide range of physiological and behavioral events. Here, we generated a new line of transgenic medaka (Oryzias latipes), which allowed us to monitor AVT neurons by enhanced green fluorescent protein (EGFP) and demonstrate AVT neuronal development in the embryo and the projection of AVT neurons in the adult brain of avt-egfp transgenic medaka. The onset of AVT expression manifested at 2 days postfertilization (dpf) as a pair of signals in the telencephalon of the brain. The telencephalic AVT neurons migrated and converged on the preoptic area (POA) by 4dpf. At the same stage, another onset of AVT expression manifested in the central optic tectum (OT), and they migrated to the ventral part of the hypothalamus (VH) by 6dpf. In the adult brain, the AVT somata with EGFP signals existed in the gigantocellular POA (gPOA), magnocellular POA (mPOA), and parvocellular POA (pPOA) and in the VH. Whereas the major projection of AVT fibers was found from the pPOA and VH to the posterior pituitary, it was also found that AVT neurons in the three POAs send their fibers into wide regions of the brain such as the telencephalon, mesencephalon and diencephalon. This study suggests that the avt-egfp transgenic medaka is a useful model to explore AVT neuronal development and function. PMID:26739197

  16. Neuregulin 1 as an endogenous regulator of nicotinic acetylcholine receptors in adult major pelvic ganglion neurons.

    PubMed

    Kim, Han-Gyu; Cho, Sung-Min; Lee, Choong-Ku; Jeong, Seong-Woo

    2015-08-01

    We investigated whether endogenous neuregulin 1 (NRG1) is released in a soluble form (called sNRG1) and upregulates expression of nicotinic acetylcholine receptor (nAChR) in autonomic major pelvic ganglion (MPG) neurons of adult rats. To elicit the release of sNRG1, either the hypogastric nerve or the pelvic nerve was electrically stimulated. Then, the MPG-conditioned medium (CM) was subjected to western blotting using an antibody directed against the N-terminal ectodomain of NRG1. Both sympathetic and parasympathetic nerve activation elicited the release of sNRG1 from MPG neurons in a frequency-dependent manner. The sNRG1 release was also induced by treatment of MPG neurons with either high KCl or neurotrophic factors. The biological activity of the released sNRG1 was detected by tyrosine phosphorylation (p185) of the ErbB2 receptors in MPG neurons. When MPG neurons were incubated for 6 h in the CM, the protein level of the nAChR α3 subunit and ACh-induced current (IACh) density were significantly increased. The CM-induced changes in IACh was abolished by a selective ErbB2 tyrosine kinase inhibitor. Taken together, these data suggest that NRG1 functions as an endogenous regulator of nAChR expression in adult MPG neurons. PMID:26043693

  17. Morphology and Intrinsic Excitability of Regenerating Sensory and Motor Neurons Grown on a Line Micropattern

    PubMed Central

    Benzina, Ouafa; Cloitre, Thierry; Martin, Marta; Raoul, Cédric; Gergely, Csilla; Scamps, Frédérique

    2014-01-01

    Axonal regeneration is one of the greatest challenges in severe injuries of peripheral nerve. To provide the bridge needed for regeneration, biological or synthetic tubular nerve constructs with aligned architecture have been developed. A key point for improving axonal regeneration is assessing the effects of substrate geometry on neuronal behavior. In the present study, we used an extracellular matrix-micropatterned substrate comprising 3 µm wide lines aimed to physically mimic the in vivo longitudinal axonal growth of mice peripheral sensory and motor neurons. Adult sensory neurons or embryonic motoneurons were seeded and processed for morphological and electrical activity analyses after two days in vitro. We show that micropattern-guided sensory neurons grow one or two axons without secondary branching. Motoneurons polarity was kept on micropattern with a long axon and small dendrites. The micro-patterned substrate maintains the growth promoting effects of conditioning injury and demonstrates, for the first time, that neurite initiation and extension could be differentially regulated by conditioning injury among DRG sensory neuron subpopulations. The micro-patterned substrate impacts the excitability of sensory neurons and promotes the apparition of firing action potentials characteristic for a subclass of mechanosensitive neurons. The line pattern is quite relevant for assessing the regenerative and developmental growth of sensory and motoneurons and offers a unique model for the analysis of the impact of geometry on the expression and the activity of mechanosensitive channels in DRG sensory neurons. PMID:25329060

  18. Neuronal production, migration, and differentiation in a vocal control nucleus of the adult female canary brain.

    PubMed Central

    Goldman, S A; Nottebohm, F

    1983-01-01

    The vocal control nucleus designated HVc (hyperstriatum ventrale, pars caudalis) of adult female canaries expands in response to systemic testosterone administration, which also induces the females to sing in a male-like manner. We became interested in the possibility of neurogenesis as a potential basis for this phenomenon. Intact adult female canaries were injected with [3H]thymidine over a 2-day period. Some birds were given testosterone implants at various times before thymidine. The birds were sacrificed 5 wk after hormone implantation, and their brains were processed for autoradiography. In parallel control experiments, some birds were given implants of cholesterol instead of testosterone. All birds showed considerable numbers of labeled neurons, glia, endothelia, and ventricular zone cells in and around HVc. Ultrastructural analysis confirmed the identity of these labeled neurons. Cholesterol- and testosterone-treated birds had similar neuronal labeling indices, which ranged from 1.8% to 4.0% in HVc. Thus, neurogenesis occurred in these adults independently of exogenous hormone treatment. Conversely, both glial and endothelial proliferation rates were markedly stimulated by exogenous testosterone treatment. We determined the origin of the thymidine-incorporating neurons by sacrificing two thymidine-treated females soon after their thymidine injections, precluding any significant migration of newly labeled cells. Analysis of these brains revealed no cells of neuronal morphology present in HVc but a very heavily labeled ventricular zone overlying HVc. We conclude that neuronal precursors exist in the HVc ventricular zone that incorporate tritiated thymidine during the S phase preceding their mitosis; after division these cells migrate into, and to some extent beyond, HVc. This ventricular zone neurogenesis seems to be a normally occurring phenomenon in intact adult female canaries. Images PMID:6572982

  19. Altered Purinergic Signaling in Colorectal Dorsal Root Ganglion Neurons Contributes to Colorectal Hypersensitivity

    PubMed Central

    La, Jun-Ho; Bielefeldt, Klaus; Gebhart, G. F.

    2010-01-01

    Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by pain and hypersensitivity in the relative absence of colon inflammation or structural changes. To assess the role of P2X receptors expressed in colorectal dorsal root ganglion (c-DRG) neurons and colon hypersensitivity, we studied excitability and purinergic signaling of retrogradely labeled mouse thoracolumbar (TL) and lumbosacral (LS) c-DRG neurons after intracolonic treatment with saline or zymosan (which reproduces 2 major features of IBS—persistent colorectal hypersensitivity without inflammation) using patch-clamp, immunohistochemical, and RT-PCR techniques. Although whole cell capacitances did not differ between LS and TL c-DRG neurons and were not changed after zymosan treatment, membrane excitability was increased in LS and TL c-DRG neurons from zymosan-treated mice. Purinergic agonist adenosine-5′-triphosphate (ATP) and α,β-methylene ATP [α,β-meATP] produced inward currents in TL c-DRG neurons were predominantly P2X3-like fast (∼70% of responsive neurons); P2X2/3-like slow currents were more common in LS c-DRG neurons (∼35% of responsive neurons). Transient currents were not produced by either agonist in c-DRG neurons from P2X3−/− mice. Neither total whole cell Kv current density nor the sustained or transient Kv components was changed in c-DRG neurons after zymosan treatment. The number of cells expressing P2X3 protein and its mRNA and the kinetic properties of ATP- and α,β-meATP-evoked currents in c-DRG neurons were not changed by zymosan treatment. However, the EC50 of α,β-meATP for the fast current decreased significantly in TL c-DRG neurons. These findings suggest that colorectal hypersensitivity produced by intracolonic zymosan increases excitability and enhances purinergic signaling in c-DRG neurons. PMID:20861433

  20. Altered purinergic signaling in colorectal dorsal root ganglion neurons contributes to colorectal hypersensitivity.

    PubMed

    Shinoda, Masamichi; La, Jun-Ho; Bielefeldt, Klaus; Gebhart, G F

    2010-12-01

    Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by pain and hypersensitivity in the relative absence of colon inflammation or structural changes. To assess the role of P2X receptors expressed in colorectal dorsal root ganglion (c-DRG) neurons and colon hypersensitivity, we studied excitability and purinergic signaling of retrogradely labeled mouse thoracolumbar (TL) and lumbosacral (LS) c-DRG neurons after intracolonic treatment with saline or zymosan (which reproduces 2 major features of IBS-persistent colorectal hypersensitivity without inflammation) using patch-clamp, immunohistochemical, and RT-PCR techniques. Although whole cell capacitances did not differ between LS and TL c-DRG neurons and were not changed after zymosan treatment, membrane excitability was increased in LS and TL c-DRG neurons from zymosan-treated mice. Purinergic agonist adenosine-5'-triphosphate (ATP) and α,β-methylene ATP [α,β-meATP] produced inward currents in TL c-DRG neurons were predominantly P2X(3)-like fast (∼70% of responsive neurons); P2X(2/3)-like slow currents were more common in LS c-DRG neurons (∼35% of responsive neurons). Transient currents were not produced by either agonist in c-DRG neurons from P2X(3)(-/-) mice. Neither total whole cell Kv current density nor the sustained or transient Kv components was changed in c-DRG neurons after zymosan treatment. The number of cells expressing P2X(3) protein and its mRNA and the kinetic properties of ATP- and α,β-meATP-evoked currents in c-DRG neurons were not changed by zymosan treatment. However, the EC(50) of α,β-meATP for the fast current decreased significantly in TL c-DRG neurons. These findings suggest that colorectal hypersensitivity produced by intracolonic zymosan increases excitability and enhances purinergic signaling in c-DRG neurons. PMID:20861433

  1. Newborn GnRH neurons in the adult forebrain of the ring dove.

    PubMed

    Cheng, Mei-Fang; Alexander, Katherine; Zhou, Shiliang; Bonder, Edward; Chuang, Ling-Shiang

    2011-06-01

    The preoptic area of the hypothalamus is a key area that produces gonadotrophin-releasing hormone (GnRH). In birds, the chicken GnRH-I-form neurons are responsible for the hypothalamus-pituitary-gonadal system, which controls reproduction. In the ring dove, electrolytic lesion in the adult hypothalamus induces neurogenesis. In this study, we determined whether adult neurogenesis is involved in repairing GnRH neurons, specifically by generating newborn cells exhibiting GnRH-I immunoreactive properties. We selectively applied electrolytic lesions to three different regions of the diencephalon, including the preoptic area, which contains GnRH-I neurons, and identified new cells (BrdU-positive cells) that co-labeled with GnRH-I-immunoreactive cells. The BrdU(+)/GnRH(+) double labeled cells were then confirmed with confocal laser analysis. In brains of both male and female ring doves we found new neurons at the lesion site of the preoptic region that were GnRH-I immunoreactive. However, the total number of GnRH neurons in the lesioned brains was less than that of sham-lesioned brains. When two other regions of the diencephalon that contain GnRH-I neurons were damaged, no recruitment of new GnRH-I neurons was detected. The rate of neurogenesis depends on the bird's reproductive phase when the lesion was applied. We found BrdU(+)/GnRH(+) double-labeled cells almost exclusively during the pre-laying phase when birds are engaged in active courtship that leads to egg laying. Our observations suggest that recruitment of GnRH immunoreactive new neurons is restricted to the hypothalamic region and is sensitive to the reproductive stage of the birds. PMID:21443878

  2. Cerebellar stem cells do not produce neurons and astrocytes in adult mouse

    SciTech Connect

    Su, Xin; Guan, Wuqiang; Yu, Yong-Chun; Fu, Yinghui

    2014-07-18

    Highlights: • No new neurons and astrocytes are generated in adult mouse cerebellum. • Very few mash1{sup +} or nestin{sup +} stem cells exist, and most of them are quiescent. • Cell proliferation rate is diversified among cerebellar regions and decreases over time. - Abstract: Although previous studies implied that cerebellar stem cells exist in some adult mammals, little is known about whether these stem cells can produce new neurons and astrocytes. In this study by bromodeoxyuridine (BrdU) intraperitoneal (i.p.) injection, we found that there are abundant BrdU{sup +} cells in adult mouse cerebellum, and their quantity and density decreases significantly over time. We also found cell proliferation rate is diversified in different cerebellar regions. Among these BrdU{sup +} cells, very few are mash1{sup +} or nestin{sup +} stem cells, and the vast majority of cerebellar stem cells are quiescent. Data obtained by in vivo retrovirus injection indicate that stem cells do not produce neurons and astrocytes in adult mouse cerebellum. Instead, some cells labeled by retrovirus are Iba1{sup +} microglia. These results indicate that very few stem cells exist in adult mouse cerebellum, and none of these stem cells contribute to neurogenesis and astrogenesis under physiological condition.

  3. Neuronal mechanisms of motor learning and motor memory consolidation in healthy old adults.

    PubMed

    Berghuis, K M M; Veldman, M P; Solnik, S; Koch, G; Zijdewind, I; Hortobágyi, T

    2015-06-01

    It is controversial whether or not old adults are capable of learning new motor skills and consolidate the performance gains into motor memory in the offline period. The underlying neuronal mechanisms are equally unclear. We determined the magnitude of motor learning and motor memory consolidation in healthy old adults and examined if specific metrics of neuronal excitability measured by magnetic brain stimulation mediate the practice and retention effects. Eleven healthy old adults practiced a wrist extension-flexion visuomotor skill for 20 min (MP, 71.3 years), while a second group only watched the templates without movements (attentional control, AC, n = 11, 70.5 years). There was 40 % motor learning in MP but none in AC (interaction, p < 0.001) with the skill retained 24 h later in MP and a 16 % improvement in AC. Corticospinal excitability at rest and during task did not change, but when measured during contraction at 20 % of maximal force, it strongly increased in MP and decreased in AC (interaction, p = 0.002). Intracortical inhibition at rest and during the task decreased and facilitation at rest increased in MP, but these metrics changed in the opposite direction in AC. These neuronal changes were especially profound at retention. Healthy old adults can learn a new motor skill and consolidate the learned skill into motor memory, processes that are most likely mediated by disinhibitory mechanisms. These results are relevant for the increasing number of old adults who need to learn and relearn movements during motor rehabilitation. PMID:25956604

  4. Autocrine action of BDNF on dendrite development of adult-born hippocampal neurons.

    PubMed

    Wang, Liang; Chang, Xingya; She, Liang; Xu, Duo; Huang, Wei; Poo, Mu-ming

    2015-06-01

    Dendrite development of newborn granule cells (GCs) in the dentate gyrus of adult hippocampus is critical for their incorporation into existing hippocampal circuits, but the cellular mechanisms regulating their dendrite development remains largely unclear. In this study, we examined the function of brain-derived neurotrophic factor (BDNF), which is expressed in adult-born GCs, in regulating their dendrite morphogenesis. Using retrovirus-mediated gene transfection, we found that deletion and overexpression of BDNF in adult-born GCs resulted in the reduction and elevation of dendrite growth, respectively. This effect was mainly due to the autocrine rather than paracrine action of BDNF, because deletion of BDNF only in the newborn GCs resulted in dendrite abnormality of these neurons to a similar extent as that observed in conditional knockout (cKO) mice with BDNF deleted in the entire forebrain. Furthermore, selective expression of BDNF in adult-born GCs in BDNF cKO mice fully restored normal dendrite development. The BDNF autocrine action was also required for the development of normal density of spines and normal percentage of spines containing the postsynaptic marker PSD-95, suggesting autocrine BDNF regulation of synaptogenesis. Furthermore, increased dendrite growth of adult-born GCs caused by voluntary exercise was abolished by BDNF deletion specifically in these neurons and elevated dendrite growth due to BDNF overexpression in these neurons was prevented by reducing neuronal activity with coexpression of inward rectifier potassium channels, consistent with activity-dependent autocrine BDNF secretion. Therefore, BDNF expressed in adult-born GCs plays a critical role in dendrite development by acting as an autocrine factor. PMID:26041908

  5. Adult human nasal mesenchymal-like stem cells restore cochlear spiral ganglion neurons after experimental lesion.

    PubMed

    Bas, Esperanza; Van De Water, Thomas R; Lumbreras, Vicente; Rajguru, Suhrud; Goss, Garrett; Hare, Joshua M; Goldstein, Bradley J

    2014-03-01

    A loss of sensory hair cells or spiral ganglion neurons from the inner ear causes deafness, affecting millions of people. Currently, there is no effective therapy to repair the inner ear sensory structures in humans. Cochlear implantation can restore input, but only if auditory neurons remain intact. Efforts to develop stem cell-based treatments for deafness have demonstrated progress, most notably utilizing embryonic-derived cells. In an effort to bypass limitations of embryonic or induced pluripotent stem cells that may impede the translation to clinical applications, we sought to utilize an alternative cell source. Here, we show that adult human mesenchymal-like stem cells (MSCs) obtained from nasal tissue can repair spiral ganglion loss in experimentally lesioned cochlear cultures from neonatal rats. Stem cells engraft into gentamicin-lesioned organotypic cultures and orchestrate the restoration of the spiral ganglion neuronal population, involving both direct neuronal differentiation and secondary effects on endogenous cells. As a physiologic assay, nasal MSC-derived cells engrafted into lesioned spiral ganglia demonstrate responses to infrared laser stimulus that are consistent with those typical of excitable cells. The addition of a pharmacologic activator of the canonical Wnt/β-catenin pathway concurrent with stem cell treatment promoted robust neuronal differentiation. The availability of an effective adult autologous cell source for inner ear tissue repair should contribute to efforts to translate cell-based strategies to the clinic. PMID:24172073

  6. Two Cell Circuits of Oriented Adult Hippocampal Neurons on Self-Assembled Monolayers for Use in the Study of Neuronal Communication in a Defined System

    PubMed Central

    2013-01-01

    In this study, we demonstrate the directed formation of small circuits of electrically active, synaptically connected neurons derived from the hippocampus of adult rats through the use of engineered chemically modified culture surfaces that orient the polarity of the neuronal processes. Although synaptogenesis, synaptic communication, synaptic plasticity, and brain disease pathophysiology can be studied using brain slice or dissociated embryonic neuronal culture systems, the complex elements found in neuronal synapses makes specific studies difficult in these random cultures. The study of synaptic transmission in mature adult neurons and factors affecting synaptic transmission are generally studied in organotypic cultures, in brain slices, or in vivo. However, engineered neuronal networks would allow these studies to be performed instead on simple functional neuronal circuits derived from adult brain tissue. Photolithographic patterned self-assembled monolayers (SAMs) were used to create the two-cell “bidirectional polarity” circuit patterns. This pattern consisted of a cell permissive SAM, N-1[3-(trimethoxysilyl)propyl] diethylenetriamine (DETA), and was composed of two 25 μm somal adhesion sites connected with 5 μm lines acting as surface cues for guided axonal and dendritic regeneration. Surrounding the DETA pattern was a background of a non-cell-permissive poly(ethylene glycol) (PEG) SAM. Adult hippocampal neurons were first cultured on coverslips coated with DETA monolayers and were later passaged onto the PEG-DETA bidirectional polarity patterns in serum-free medium. These neurons followed surface cues, attaching and regenerating only along the DETA substrate to form small engineered neuronal circuits. These circuits were stable for more than 21 days in vitro (DIV), during which synaptic connectivity was evaluated using basic electrophysiological methods. PMID:23611164

  7. Cells from the adult corneal stroma can be reprogrammed to a neuron-like cell using exogenous growth factors

    SciTech Connect

    Greene, Carol Ann Chang, Chuan-Yuan; Fraser, Cameron J.; Nelidova, Dasha E.; Chen, Jing A.; Lim, Angela; Brebner, Alex; McGhee, Jennifer; Sherwin, Trevor; Green, Colin R.

    2014-03-10

    Cells thought to be stem cells isolated from the cornea of the eye have been shown to exhibit neurogenic potential. We set out to uncover the identity and location of these cells within the cornea and to elucidate their neuronal protein and gene expression profile during the process of switching to a neuron-like cell. Here we report that every cell of the adult human and rat corneal stroma is capable of differentiating into a neuron-like cell when treated with neurogenic differentiation specifying growth factors. Furthermore, the expression of genes regulating neurogenesis and mature neuronal structure and function was increased. The switch from a corneal stromal cell to a neuron-like cell was also shown to occur in vivo in intact corneas of living rats. Our results clearly indicate that lineage specifying growth factors can affect changes in the protein and gene expression profiles of adult cells, suggesting that possibly many adult cell populations can be made to switch into another type of mature cell by simply modifying the growth factor environment. - Highlights: • Adult corneal stromal cells can differentiated into neuron-like cells. • Neuronal specification of the adult stromal cell population is stochastic. • Neuronal specification in an adult cell population can be brought about by growth factors.

  8. Reducing Lissencephaly-1 levels augments mitochondrial transport and has a protective effect in adult Drosophila neurons

    PubMed Central

    Vagnoni, Alessio; Hoffmann, Patrick C.; Bullock, Simon L.

    2016-01-01

    ABSTRACT Defective transport of mitochondria in axons is implicated in the pathogenesis of several age-associated neurodegenerative diseases. However, the regulation and function of axonal mitochondrial motility during normal ageing is poorly understood. Here, we use novel imaging procedures to characterise axonal transport of these organelles in the adult Drosophila wing nerve. During early adult life there is a boost and progressive decline in the proportion of mitochondria that are motile, which is not due to general changes in cargo transport. Experimental inhibition of the mitochondrial transport machinery specifically in adulthood accelerates the appearance of focal protein accumulations in ageing axons, which is suggestive of defects in protein homeostasis. Unexpectedly, lowering levels of Lissencephaly-1 (Lis1), a dynein motor co-factor, augments axonal mitochondrial transport in ageing wing neurons. Lis1 mutations suppress focal protein accumulations in ageing neurons, including those caused by interfering with the mitochondrial transport machinery. Our data provide new insights into the dynamics of mitochondrial motility in adult neurons in vivo, identify Lis1 as a negative regulator of transport of these organelles, and provide evidence of a link between mitochondrial movement and neuronal protein homeostasis. PMID:26598558

  9. Class 3 semaphorin mediates dendrite growth in adult newborn neurons through Cdk5/FAK pathway.

    PubMed

    Ng, Teclise; Ryu, Jae Ryun; Sohn, Jae Ho; Tan, Terence; Song, Hongjun; Ming, Guo-Li; Goh, Eyleen L K

    2013-01-01

    Class 3 semaphorins are well-known axonal guidance cues during the embryonic development of mammalian nervous system. However, their activity on postnatally differentiated neurons in neurogenic regions of adult brains has not been characterized. We found that silencing of semaphorin receptors neuropilins (NRP) 1 or 2 in neural progenitors at the adult mouse dentate gyrus resulted in newly differentiated neurons with shorter dendrites and simpler branching in vivo. Tyrosine phosphorylation (Tyr 397) and serine phosphorylation (Ser 732) of FAK were essential for these effects. Semaphorin 3A and 3F mediate serine phosphorylation of FAK through the activation of Cdk5. Silencing of either Cdk5 or FAK in newborn neurons phenocopied the defects in dendritic development seen upon silencing of NRP1 or NRP2. Furthermore, in vivo overexpression of Cdk5 or FAK rescued the dendritic phenotypes seen in NRP1 and NRP2 deficient neurons. These results point to a novel role for class 3 semaphorins in promoting dendritic growth and branching during adult hippocampal neurogenesis through the activation of Cdk5-FAK signaling pathway. PMID:23762397

  10. Activation of local inhibitory circuits in the dentate gyrus by adult-born neurons.

    PubMed

    Drew, Liam J; Kheirbek, Mazen A; Luna, Victor M; Denny, Christine A; Cloidt, Megan A; Wu, Melody V; Jain, Swati; Scharfman, Helen E; Hen, René

    2016-06-01

    Robust incorporation of new principal cells into pre-existing circuitry in the adult mammalian brain is unique to the hippocampal dentate gyrus (DG). We asked if adult-born granule cells (GCs) might act to regulate processing within the DG by modulating the substantially more abundant mature GCs. Optogenetic stimulation of a cohort of young adult-born GCs (0 to 7 weeks post-mitosis) revealed that these cells activate local GABAergic interneurons to evoke strong inhibitory input to mature GCs. Natural manipulation of neurogenesis by aging-to decrease it-and housing in an enriched environment-to increase it-strongly affected the levels of inhibition. We also demonstrated that elevating activity in adult-born GCs in awake behaving animals reduced the overall number of mature GCs activated by exploration. These data suggest that inhibitory modulation of mature GCs may be an important function of adult-born hippocampal neurons. © 2015 Wiley Periodicals, Inc. PMID:26662922

  11. Differential neurotrophic regulation of sodium and calcium channels in an adult sympathetic neuron.

    PubMed

    Ford, Christopher P; Wong, Kenneth V; Lu, Van B; Posse de Chaves, Elena; Smith, Peter A

    2008-03-01

    Adult neuronal phenotype is maintained, at least in part, by the sensitivity of individual neurons to a specific selection of neurotrophic factors and the availability of such factors in the neurons' environment. Nerve growth factor (NGF) increases the functional expression of Na(+) channel currents (I(Na)) and both N- and L-type Ca(2+) currents (I(Ca,N) and I(Ca,L)) in adult bullfrog sympathetic ganglion (BFSG) B-neurons. The effects of NGF on I(Ca) involve the mitogen-activated protein kinase (MAPK) pathway. Prolonged exposure to the ganglionic neurotransmitter luteinizing hormone releasing hormone (LHRH) also increases I(Ca,N) but the transduction mechanism remains to be elucidated as does the transduction mechanism for NGF regulation of Na(+) channels. We therefore exposed cultured BFSG B-neurons to chicken II LHRH (0.45 microM; 6-9 days) or to NGF (200 ng/ml; 9-10 days) and used whole cell recording, immunoblot analysis, and ras or rap-1 pulldown assays to study effects of various inhibitors and activators of transduction pathways. We found that 1) LHRH signals via ras-MAPK to increase I(Ca,N), 2) this effect is mediated via protein kinase C-beta (PKC-beta-IotaIota), 3) protein kinase A (PKA) is necessary but not sufficient to effect transduction, 4) NGF signals via phosphatidylinositol 3-kinase (PI3K) to increase I(Na), and 5) long-term exposure to LHRH fails to affect I(Na). Thus downstream signaling from LHRH has access to the ras-MAPK pathway but not to the PI3K pathway. This allows for differential retrograde and anterograde neurotrophic regulation of sodium and calcium channels in an adult sympathetic neuron. PMID:18216230

  12. Environmental enrichment influences neuronal stem cells in the adult crayfish brain

    PubMed Central

    Ayub, Neishay; Benton, Jeanne L.; Zhang, Yi; Beltz, Barbara S.

    2011-01-01

    New neurons are incorporated throughout life into the brains of many vertebrate and non-vertebrate species. This process of adult neurogenesis is regulated by a variety of external and endogenous factors, including environmental enrichment, which increases the production of neurons in juvenile mice and crayfish. The primary goal of the present study was to exploit the spatial separation of the neuronal precursor cell lineage in crayfish to determine which generation(s) of precursors is altered by environmental conditions. Further, in crayfish, an intimate relationship between the 1st generation neuronal precursors (stem cells) and cells circulating in the hemolymph has been proposed (Zhang et al., 2009). Therefore, a second goal was to assess whether environmental enrichment alters the numbers or types of cells circulating in the hemolymph. We find that neurogenesis in the brains of sexually differentiated procambarid crayfish is enhanced by environmental enrichment as previously demonstrated by Sandeman and Sandeman (2000) in young, sexually undifferentiated Cherax destructor. We also show that environmental enrichment increases the cell cycle rate of neuronal stem cells. While there was no effect of environment on the overall numbers of cells circulating in the hemolymph, enrichment resulted in increased expression of glutamine synthetase, a marker of the neuronal stem cells, in a small percentage of circulating cells; there was little or no expression of this enzyme in hemolymph cells extracted from deprived animals. Thus, environmental enrichment influences the rate of neuronal stem cell division in adult crayfish, as well as the composition of cells circulating in the hemolymph. PMID:21485010

  13. A simple method for imaging axonal transport in aging neurons using the adult Drosophila wing.

    PubMed

    Vagnoni, Alessio; Bullock, Simon L

    2016-09-01

    There is growing interest in the link between axonal cargo transport and age-associated neuronal dysfunction. The study of axonal transport in neurons of adult animals requires intravital or ex vivo imaging approaches, which are laborious and expensive in vertebrate models. We describe simple, noninvasive procedures for imaging cargo motility within axons using sensory neurons of the translucent Drosophila wing. A key aspect is a method for mounting the intact fly that allows detailed imaging of transport in wing neurons. Coupled with existing genetic tools in Drosophila, this is a tractable system for studying axonal transport over the life span of an animal and thus for characterization of the relationship between cargo dynamics, neuronal aging and disease. Preparation of a sample for imaging takes ∼5 min, with transport typically filmed for 2-3 min per wing. We also document procedures for the quantification of transport parameters from the acquired images and describe how the protocol can be adapted to study other cell biological processes in aging neurons. PMID:27560175

  14. Adult axolotls can regenerate original neuronal diversity in response to brain injury

    PubMed Central

    Amamoto, Ryoji; Huerta, Violeta Gisselle Lopez; Takahashi, Emi; Dai, Guangping; Grant, Aaron K; Fu, Zhanyan; Arlotta, Paola

    2016-01-01

    The axolotl can regenerate multiple organs, including the brain. It remains, however, unclear whether neuronal diversity, intricate tissue architecture, and axonal connectivity can be regenerated; yet, this is critical for recovery of function and a central aim of cell replacement strategies in the mammalian central nervous system. Here, we demonstrate that, upon mechanical injury to the adult pallium, axolotls can regenerate several of the populations of neurons present before injury. Notably, regenerated neurons acquire functional electrophysiological traits and respond appropriately to afferent inputs. Despite the ability to regenerate specific, molecularly-defined neuronal subtypes, we also uncovered previously unappreciated limitations by showing that newborn neurons organize within altered tissue architecture and fail to re-establish the long-distance axonal tracts and circuit physiology present before injury. The data provide a direct demonstration that diverse, electrophysiologically functional neurons can be regenerated in axolotls, but challenge prior assumptions of functional brain repair in regenerative species. DOI: http://dx.doi.org/10.7554/eLife.13998.001 PMID:27156560

  15. Doublecortin (DCX) is not Essential for Survival and Differentiation of Newborn Neurons in the Adult Mouse Dentate Gyrus

    PubMed Central

    Dhaliwal, Jagroop; Xi, Yanwei; Bruel-Jungerman, Elodie; Germain, Johanne; Francis, Fiona; Lagace, Diane C.

    2016-01-01

    In the adult brain, expression of the microtubule-associated protein Doublecortin (DCX) is associated with neural progenitor cells (NPCs) that give rise to new neurons in the dentate gyrus. Many studies quantify the number of DCX-expressing cells as a proxy for the level of adult neurogenesis, yet no study has determined the effect of removing DCX from adult hippocampal NPCs. Here, we use a retroviral and inducible mouse transgenic approach to either knockdown or knockout DCX from adult NPCs in the dentate gyrus and examine how this affects cell survival and neuronal maturation. Our results demonstrate that shRNA-mediated knockdown of DCX or Cre-mediated recombination in floxed DCX mice does not alter hippocampal neurogenesis and does not change the neuronal fate of the NPCs. Together these findings show that the survival and maturation of adult-generated hippocampal neurons does not require DCX. PMID:26793044

  16. Transplanted neurons integrate into adult retinas and respond to light.

    PubMed

    Venugopalan, Praseeda; Wang, Yan; Nguyen, Tu; Huang, Abigail; Muller, Kenneth J; Goldberg, Jeffrey L

    2016-01-01

    Retinal ganglion cells (RGCs) degenerate in diseases like glaucoma and are not replaced in adult mammals. Here we investigate whether transplanted RGCs can integrate into the mature retina. We have transplanted GFP-labelled RGCs into uninjured rat retinas in vivo by intravitreal injection. Transplanted RGCs acquire the general morphology of endogenous RGCs, with axons orienting towards the optic nerve head of the host retina and dendrites growing into the inner plexiform layer. Preliminary data show in some cases GFP(+) axons extending within the host optic nerves and optic tract, reaching usual synaptic targets in the brain, including the lateral geniculate nucleus and superior colliculus. Electrophysiological recordings from transplanted RGCs demonstrate the cells' electrical excitability and light responses similar to host ON, ON-OFF and OFF RGCs, although less rapid and with greater adaptation. These data present a promising approach to develop cell replacement strategies in diseased retinas with degenerating RGCs. PMID:26843334

  17. Transplanted neurons integrate into adult retinas and respond to light

    PubMed Central

    Venugopalan, Praseeda; Wang, Yan; Nguyen, Tu; Huang, Abigail; Muller, Kenneth J.; Goldberg, Jeffrey L.

    2016-01-01

    Retinal ganglion cells (RGCs) degenerate in diseases like glaucoma and are not replaced in adult mammals. Here we investigate whether transplanted RGCs can integrate into the mature retina. We have transplanted GFP-labelled RGCs into uninjured rat retinas in vivo by intravitreal injection. Transplanted RGCs acquire the general morphology of endogenous RGCs, with axons orienting towards the optic nerve head of the host retina and dendrites growing into the inner plexiform layer. Preliminary data show in some cases GFP+ axons extending within the host optic nerves and optic tract, reaching usual synaptic targets in the brain, including the lateral geniculate nucleus and superior colliculus. Electrophysiological recordings from transplanted RGCs demonstrate the cells' electrical excitability and light responses similar to host ON, ON–OFF and OFF RGCs, although less rapid and with greater adaptation. These data present a promising approach to develop cell replacement strategies in diseased retinas with degenerating RGCs. PMID:26843334

  18. Muscarinic acetylcholine receptor modulation of mu (mu) opioid receptors in adult rat sphenopalatine ganglion neurons.

    PubMed

    Margas, Wojciech; Mahmoud, Saifeldin; Ruiz-Velasco, Victor

    2010-01-01

    The sphenopalatine ganglion (SPG) neurons represent the parasympathetic branch of the autonomic nervous system involved in controlling cerebral blood flow. In the present study, we examined the coupling mechanism between mu (mu) opioid receptors (MOR) and muscarinic acetylcholine receptors (mAChR) with Ca(2+) channels in acutely dissociated adult rat SPG neurons. Successful MOR activation was recorded in approximately 40-45% of SPG neurons employing the whole cell variant of the patch-clamp technique. In addition, immunofluorescence assays indicated that MOR are not expressed in all SPG neurons while M(2) mAChR staining was evident in all neurons. The concentration-response relationships generated with morphine and [d-Ala2-N-Me-Phe4-Glycol5]-enkephalin (DAMGO) showed IC(50) values of 15.2 and 56.1 nM and maximal Ca(2+) current inhibition of 26.0 and 38.7%, respectively. Activation of MOR or M(2) mAChR with morphine or oxotremorine-methiodide (Oxo-M), respectively, resulted in voltage-dependent inhibition of Ca(2+) currents via coupling with Galpha(i/o) protein subunits. The acute prolonged exposure (10 min) of neurons to morphine or Oxo-M led to the homologous desensitization of MOR and M(2) mAChR, respectively. The prolonged stimulation of M(2) mAChR with Oxo-M resulted in heterologous desensitization of morphine-mediated Ca(2+) current inhibition, and was sensitive to the M(2) mAChR blocker methoctramine. On the other hand, when the neurons were exposed to morphine or DAMGO for 10 min, heterologous desensitization of M(2) mAChR was not observed. These results suggest that in rat SPG neurons activation of M(2) mAChR likely modulates opioid transmission in the brain vasculature to adequately maintain cerebral blood flow. PMID:19889856

  19. Nest of Origin Predicts Adult Neuron Addition Rates in the Vocal Control System of the Zebra Finch

    PubMed Central

    Hurley, Patrick; Pytte, Carolyn; Kirn, John R.

    2008-01-01

    Neurogenesis and neuronal replacement in adulthood represent dramatic forms of plasticity that might serve as a substrate for behavioral flexibility. In songbirds, neurons are continually replaced in HVC (used as a proper name), a pre-motor region necessary for the production of learned vocalizations. There are large individual differences in HVC neuron addition. Some of this variation is probably due to individual differences in adult experience; however, it is also possible that heritability or experience early in development constrains the levels of adult neuron addition. As a step toward addressing the latter two possibilities, we explored the extent to which nest of origin predicts rates of HVC neuron addition in adult male zebra finches. One month after injections of [3H]-thymidine to mark dividing cells, neuron addition in HVC was found to co-vary among birds that had been nest mates, even when they were housed in different cages as adults. We also tested whether nest mate co-variation might be due to shared adult auditory experience by measuring neuron addition in nest mate pairs after one member was deafened. There were significant differences in neuron addition between hearing and deaf birds but nest mate relationships persisted. These results suggest that variation in genotype and/or early pre- or postnatal experience can account for a large fraction of adult variation in rates of neuron addition. These results also suggest that a major constraint on neurogenesis and the capacity to adjust rates of neuron addition in response to adult auditory experience is established early in development. PMID:18431053

  20. 42 CFR 412.60 - DRG classification and weighting factors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Section 412.60 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... appropriate weighting factor that reflects the estimated relative cost of hospital resources used with respect... DRG classification system provides a DRG, and an appropriate weighting factor, for the group of...

  1. 42 CFR 412.60 - DRG classification and weighting factors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Section 412.60 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... appropriate weighting factor that reflects the estimated relative cost of hospital resources used with respect... DRG classification system provides a DRG, and an appropriate weighting factor, for the group of...

  2. 42 CFR 412.60 - DRG classification and weighting factors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Section 412.60 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... appropriate weighting factor that reflects the estimated relative cost of hospital resources used with respect... DRG classification system provides a DRG, and an appropriate weighting factor, for the group of...

  3. 42 CFR 412.60 - DRG classification and weighting factors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Section 412.60 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... appropriate weighting factor that reflects the estimated relative cost of hospital resources used with respect... DRG classification system provides a DRG, and an appropriate weighting factor, for the group of...

  4. Stability and Autolysis of Cortical Neurons in Post-Mortem Adult Rat Brains

    PubMed Central

    Sheleg, Sergey V; LoBello, Janine R; Hixon, Hugh; Coons, Stephen W; Lowry, David; Nedzved, Mikhail K

    2008-01-01

    We investigated the dynamics of autolytic damage of the cortical neurons in adult brains for 24 hours at room temperature (+20°C) after cardiac arrest. The progressive histological and ultrastructural changes were documented using routine and immunohistochemical staining as well as electron microscopy. Our results demonstrated that there were no autolytic damages in the ultrastructure of cerebral neurons in the first 6 hours after warm cardiac arrest, in agreement with previous studies in other mammals. Interestingly, the activation of caspase-3 was observed in a significant number of neurons of the cerebellum and neocortex 9 hours following cardiac arrest. No significant changes related to autolysis were observed using amnio-cupric acid and Nissl (thionine) staining. PMID:18784829

  5. IB4-binding sensory neurons in the adult rat express a novel 3′ UTR-extended isoform of CaMK4 that is associated with its localization to axons

    PubMed Central

    Harrison, Benjamin J.; Flight, Robert M.; Gomes, Cynthia; Venkat, Gayathri; Ellis, Steven R; Sankar, Uma; Twiss, Jeffery L.; Rouchka, Eric C.; Petruska, Jeffrey C.

    2013-01-01

    Calcium/Calmodulin-dependent protein Kinase 4 (Gene and transcript: CaMK4; Protein: CaMKIV) is the nuclear effector of the Ca2+/Calmodulin Kinase (CaMK) pathway where it co-ordinates transcriptional responses. However, CaMKIV is present in the cytoplasm and axons of subpopulations of neurons, including some sensory neurons of the dorsal root ganglia (DRG), suggesting an extra-nuclear role for this protein. We observed that CaMKIV was expressed strongly in the cytoplasm and axons of a subpopulation of small diameter DRG neurons, most likely cutaneous nociceptors by virtue of their binding the isolectin IB4. In IB4+ spinal nerve axons, 20% of CaMKIV was co-localized with the endocytic marker Rab7 in axons that highly expressed CAM-Kinase-Kinase (CAMKK), an upstream activator of CaMKIV, suggesting a role for CaMKIV in signalling though signalling endosomes. Using fluorescent in situ hybridization (FISH) with riboprobes, we also observed that small diameter neurons expressed high levels of a novel 3' untranslated region (UTR) variant of CaMK4 mRNA. Using rapid amplification of cDNA ends (RACE), RT-PCR with gene-specific primers, and cDNA sequencing analyses we determined that the novel transcript contains an additional 10kb beyond the annotated gene terminus to a highly conserved alternate poly-adenylation site. qPCR analyses of fluorescent-activated cell sorted (FACS) DRG neurons confirmed that this 3'UTR-extended variant was preferentially expressed in IB4-binding neurons. Computational analyses of the 3'-UTR sequence predict that UTR-extension introduces consensus sites for RNA-binding proteins (RBPs) including the Embryonic Lethal Abnormal Vision (ELAV)/Hu family proteins. We consider the possible implications of axonal CaMKIV in the context of the unique properties of IB4-binding DRG neurons. PMID:23817991

  6. THE PROSTAGLANDIN E2 RECEPTOR, EP2, IS UPREGULATED IN THE DRG AFTER PAINFUL CERVICAL FACET JOINT INJURY IN THE RAT

    PubMed Central

    Kras, Jeffrey V.; Dong, Ling; Winkelstein, Beth A.

    2012-01-01

    Study Design This study implemented immunohistochemistry to assay prostaglandin E2 (PGE2) receptor EP2 expression in the dorsal root ganglion (DRG) of rats after painful cervical facet joint injury. Objective The objective of this study was to identify if inflammatory cascades are induced in association with cervical facet joint distraction-induced pain by investigating the time course of EP2 expression in the DRG. Summary of Background Data The cervical facet joint is a common source of neck pain and non-physiological stretch of the facet capsular ligament can initiate pain from the facet joint via mechanical injury. PGE2 levels are elevated in painful inflamed and arthritic joints, and PGE2 sensitizes joint afferents to mechanical stimulation. Although in vitro studies suggest the EP2 receptor subtype contributes to painful joint disease the EP2 response has not been investigated for any association with painful mechanical joint injury. Methods Separate groups of male Holtzman rats underwent either a painful cervical facet joint distraction injury or sham procedure. Bilateral forepaw mechanical allodynia was assessed, and immunohistochemical techniques were used to quantify EP2 expression in the DRG at days 1 and 7. Results Facet joint distraction induced mechanical allodynia that was significant (p<0.024) at all time points. Painful joint injury also significantly elevated total EP2 expression in the DRG at day 1 (p=0.009), which was maintained also at day 7 (p<0.001). Neuronal expression of EP2 in the DRG was only increased over sham levels at day 1 (p=0.013). Conclusions Painful cervical facet joint distraction induces an immediate and sustained increase of EP2 expression in the DRG, implicating peripheral inflammation in the initiation and maintenance of facet joint pain. The transient increase in neuronal EP2 suggests, as in other painful joint conditions, that after joint injury non-neuronal cells may migrate to the DRG, some of which likely express EP2

  7. Running rewires the neuronal network of adult-born dentate granule cells.

    PubMed

    Vivar, Carmen; Peterson, Benjamin D; van Praag, Henriette

    2016-05-01

    Exercise improves cognition in humans and animals. Running increases neurogenesis in the dentate gyrus of the hippocampus, a brain area important for learning and memory. It is unclear how running modifies the circuitry of new dentate gyrus neurons to support their role in memory function. Here we combine retroviral labeling with rabies virus mediated trans-synaptic retrograde tracing to define and quantify new neuron afferent inputs in young adult male C57Bl/6 mice, housed with or without a running wheel for one month. Exercise resulted in a shift in new neuron networks that may promote sparse encoding and pattern separation. Neurogenesis increased in the dorsal, but not the ventral, dentate gyrus by three-fold, whereas afferent traced cell labeling doubled in number. Regional analysis indicated that running differentially affected specific inputs. Within the hippocampus the ratio of innervation from inhibitory interneurons and glutamatergic mossy cells to new neurons was reduced. Distal traced cells were located in sub-cortical and cortical regions, including perirhinal, entorhinal and sensory cortices. Innervation from entorhinal cortex (EC) was augmented, in proportion to the running-induced enhancement of adult neurogenesis. Within EC afferent input and short-term synaptic plasticity from lateral entorhinal cortex, considered to convey contextual information to the hippocampus was increased. Furthermore, running upregulated innervation from regions important for spatial memory and theta rhythm generation, including caudo-medial entorhinal cortex and subcortical medial septum, supra- and medial mammillary nuclei. Altogether, running may facilitate contextual, spatial and temporal information encoding by increasing adult hippocampal neurogenesis and by reorganization of new neuron circuitry. PMID:26589333

  8. Adult rat bone marrow stromal cells express genes associated with dopamine neurons

    SciTech Connect

    Kramer, Brian C.; Woodbury, Dale . E-mail: WOODBURYDL@AOL.COM; Black, Ira B.

    2006-05-19

    An intensive search is underway to identify candidates to replace the cells that degenerate in Parkinson's disease (PD). To date, no suitable substitute has been found. We have recently found that adult rat bone marrow stromal cells (MSCs) can be induced to assume a neuronal phenotype in vitro. These findings may have particular relevance to the treatment of PD. We now report that adult MSCs express multiple dopaminergic genes, suggesting that they are potential candidates for cell therapy. Using RT-PCR, we have examined families of genes that are associated with the development and/or survival of dopaminergic neurons. MSCs transcribe a variety of dopaminergic genes including patched and smoothened (components of the Shh receptor), Gli-1 (downstream mediator of Shh), and Otx-1, a gene associated with formation of the mesencephalon during development. Furthermore, Shh treatment elicits a 1.5-fold increase in DNA synthesis in cultured MSCs, suggesting the presence of a functional Shh receptor complex. We have also found that MSCs transcribe and translate Nurr-1, a nuclear receptor essential for the development of dopamine neurons. In addition, MSCs express a variety of growth factor receptors including the glycosyl-phosphatidylinositol-anchored ligand-binding subunit of the GDNF receptor, GFR{alpha}1, as well as fibroblast growth factor receptors one and four. The expression of genes that are associated with the development and survival of dopamine neurons suggests a potential role for these cells in the treatment of Parkinson's disease.

  9. Adult neuronal ceroid lipofuscinosis with palmitoyl-protein thioesterase deficiency: first adult-onset patients of a childhood disease.

    PubMed

    van Diggelen, O P; Thobois, S; Tilikete, C; Zabot, M T; Keulemans, J L; van Bunderen, P A; Taschner, P E; Losekoot, M; Voznyi, Y V

    2001-08-01

    The fluorogenic enzyme assay for palmitoyl-protein thioesterase (PPT) has greatly facilitated the diagnosis of infantile neuronal ceroid lipofuscinosis (Santavuori-Haltia disease) and the search for possible new variants with atypical clinical presentation. Here, we present the first cases of adult neuronal ceroid lipofuscinosis with onset in the fourth decade of life due to a profound deficiency of PPT. The causative mutations in the CLN1 gene were the known, deleterious mutation R151X and the novel missense mutation G108R. Patients presented at onset (31 and 38 years), with psychiatric symptoms only. At present (ages 56 and 54 years), visual, verbal, and cognitive losses have progressed and both patients have cerebellar ataxia and cannot walk without support. PMID:11506414

  10. Role of α-synuclein in adult neurogenesis and neuronal maturation in the dentate gyrus

    PubMed Central

    Regensburger, Martin; Schreglmann, Sebastian; Boyer, Leah; Prots, Iryna; Rockenstein, Edward; Mante, Michael; Zhao, Chunmei; Winkler, Jürgen; Masliah, Eliezer; Gage, Fred H.

    2016-01-01

    Summary α-Synuclein has been reported to be important in modulating brain plasticity and to be a key protein in neurodegenerative diseases, including Lewy body dementia (LBD). We investigated how α-synuclein levels modulate adult neurogenesis and the development of dendritic arborization and spines in the dentate gyrus (DG), where new neurons are constantly added. In the human hippocampus, levels of endogenous α-synuclein were increased in LBD and the numbers of SOX2-positive cells were decreased. We investigated whether newly generated neurons were modulated by endogenous α-synuclein and we found increased adult neurogenesis in α/β-synuclein knockout mice. In contrast, overexpression of human wild-type α-synuclein (WTS) decreased the survival and dendritic development of newborn neurons. Endogenous α-synuclein expression levels increased the negative impact of WTS on dendrite development, suggesting a toxic effect of increasing amounts of α-synuclein. To attempt a rescue of the dendritic phenotype, we administered rolipram to activate the cAMP response element-binding protein (CREB) pathway, which led to a partial rescue of neurite development. The current work provides novel insights into the role of α-synuclein in adult hippocampal neurogenesis. PMID:23175842

  11. Sonic hedgehog signalling in neurons of adult ventrolateral nucleus tractus solitarius.

    PubMed

    Pascual, Olivier; Traiffort, Elisabeth; Baker, Darren P; Galdes, Alphonse; Ruat, Martial; Champagnat, Jean

    2005-07-01

    The transmembrane receptor Patched (Ptc) mediates the action of the diffusing factor Sonic hedgehog (Shh), which is implicated in establishing morphogenetic gradients during embryonic development. Whereas alteration of Ptc function is associated with developmental abnormalities and brain tumors, its functional activity and roles in the adult brain have yet to be elucidated. Here we describe the complementary pattern of Shh and Ptc expression in the rat dorsal vagal motor nucleus and the ventrolateral nucleus tractus solitarius (vNTS), respectively. Those two interconnected structures regulate the cardiorespiratory function during hypoxia. Bath application of a subnanomolar concentration of aminoterminal Shh protein (ShhN) to a slice preparation of the vNTS induces a rapid decrease in neuronal firing followed by a bursting activity that propagates in the neuronal network. Intracellular current injections show that bursts result from an action on the neuronal membrane electro-responsiveness. Both inhibiting and bursting effects are blocked by the monoclonal Shh antibody 5E1 and may require the Ptc binding site of ShhN. Thus, ShhN acting on specific neuronal sites controls electrophysiological properties of differentiated neurons of the vNTS. We speculate on a retrocontrol of cardiorespiratory signals in the vNTS, by Shh generated in dorsal vagal motoneurons. PMID:16045492

  12. Ionic mechanism underlying recovery of rhythmic activity in adult isolated neurons

    PubMed Central

    Haedo, Rodolfo J.; Golowasch, Jorge

    2013-01-01

    Neurons exhibit long-term excitability changes necessary for maintaining proper cell and network activity in response to various inputs and perturbations. For instance, the adult crustacean pyloric network can spontaneously recover rhythmic activity after complete shutdown resulting from permanent removal of neuromodulatory inputs. Dissociated lobster stomatogastric ganglion (STG) neurons have been shown to spontaneously develop oscillatory activity via excitability changes. Rhythmic electrical stimulation can eliminate these oscillatory patterns in some cells. The ionic mechanisms underlying these changes are only partially understood. We used dissociated crab STG neurons to study the ionic mechanisms underlying spontaneous recovery of rhythmic activity and stimulation-induced activity changes. Similar to lobster neurons, rhythmic activity spontaneously develops in crab STG neurons. Rhythmic hyperpolarizing stimulation can eliminate, but more commonly accelerate the emergence of stable oscillatory activity depending on Ca++ influx at hyperpolarized voltages. Our main finding is that up-regulation of a Ca++-current and down-regulation of a high-threshold K+-current underlies the spontaneous homeostatic development of oscillatory activity. However, because of a non-linear dependence on stimulus frequency, hyperpolarization-induced oscillations appear to be inconsistent with a homeostatic regulation of activity. We find no difference in the activity patterns or the underlying ionic currents involved between neurons of the fast pyloric and the slow gastric mill networks during the first ten days in isolation. Dynamic-clamp experiments confirm that these conductance modifications can explain the observed activity changes. We conclude that spontaneous and stimulation-induced excitability changes in STG neurons can both result in intrinsic oscillatory activity via regulation of the same two conductances. PMID:16807346

  13. Trigeminal intersubnuclear neurons: morphometry and input-dependent structural plasticity in adult rats.

    PubMed

    Martin, Yasmina B; Negredo, Pilar; Villacorta-Atienza, Jose A; Avendaño, Carlos

    2014-05-01

    Intersubnuclear neurons in the caudal division of the spinal trigeminal nucleus that project to the principal nucleus (Pr5) play an active role in shaping the receptive fields of other neurons, at different levels in the ascending sensory system that processes information originating from the vibrissae. By using retrograde labeling and digital reconstruction, we investigated the morphometry and topology of the dendritic trees of these neurons and the changes induced by long-term experience-dependent plasticity in adult male rats. Primary afferent input was either eliminated by transection of the right infraorbital nerve (IoN), or selectively altered by repeated whisker clipping on the right side. These neurons do not display asymmetries between sides in basic metric and topologic parameters (global number of trees, nodes, spines, or dendritic ends), although neurons on the left tend to have longer terminal segments. Ipsilaterally, both deafferentation (IoN transection) and deprivation (whisker trimming) reduced the density of spines, and the former also caused a global increase in total dendritic length and a relative increase in more complex arbors. Contralaterally, deafferentation reduced more complex dendritic trees, and caused a moderate decline in dendritic length and spatial reach, and a loss of spines in number and density. Deprivation caused a similar, but more profound, effect on spines. Our findings provide original quantitative descriptions of a scarcely known cell population, and show that denervation- or deprivation-derived plasticity is expressed not only by neurons at higher levels of the sensory pathways, but also by neurons in key subcortical circuits for sensory processing. PMID:24178892

  14. NEURON-SPECIFIC PHOSPHOPROTEINS AS BIOCHEMICAL INDICATORS OF NEUROTOXICITY: EFFECTS OF ACUTE ADMINISTRATION OF TRIMETHYLTIN TO THE ADULT RAT

    EPA Science Inventory

    The cytoarchitecture of the adult central nervous system is expressed by proteins specific to individual cell types. In this investigation, a subclass of these proteins, the neuron-specific phosphoproteins, was examined after the administration of trimethyltin (TMT), a neurotoxic...

  15. Amitriptyline Activates TrkA to Aid Neuronal Growth and Attenuate Anesthesia-Induced Neurodegeneration in Rat Dorsal Root Ganglion Neurons.

    PubMed

    Zheng, Xiaochun; Chen, Feng; Zheng, Ting; Huang, Fengyi; Chen, Jianghu; Tu, Wenshao

    2016-05-01

    Tricyclic antidepressant amitriptyline (AM) has been shown to exert neurotrophic activity on neurons. We thus explored whether AM may aid the neuronal development and protect anesthesia-induced neuro-injury in young spinal cord dorsal root ganglion (DRG) neurons.The DRG explants were prepared from 1-day-old rats. The effect of AM on aiding DRG neural development was examined by immunohistochemistry at dose-dependent manner. AM-induced changes in gene and protein expressions, and also phosphorylation states of tyrosine kinases receptor A (TrkA) and B (TrkB) in DRG, were examined by quantitative real-time polymerase chain reaction and western blot. The effect of AM on attenuating lidocaine-induced DRG neurodegeneration was examined by immunohistochemistry, and small interfering RNA (siRNA)-mediated TrkA/B down-regulation.Amitriptyline stimulated DRG neuronal development in dose-dependent manner, but exerted toxic effect at concentrations higher than 10 M. AM activated TrkA in DRG through phosphorylation, whereas it had little effect on TrkB-signaling pathway. AM reduced lidocaine-induced DRG neurodegeneration by regenerating neurites and growth cones. Moreover, the neuroprotection of AM on lidocaine-injured neurodegeneration was blocked by siRNA-mediated TrkA down-regulation, but not by TrkB down-regulation.Amitriptyline facilitated neuronal development and had protective effect on lidocaine-induced neurodegeneration, very likely through the activation of TrkA-signaling pathway in DRG. PMID:27149473

  16. Amitriptyline Activates TrkA to Aid Neuronal Growth and Attenuate Anesthesia-Induced Neurodegeneration in Rat Dorsal Root Ganglion Neurons

    PubMed Central

    Zheng, Xiaochun; Chen, Feng; Zheng, Ting; Huang, Fengyi; Chen, Jianghu; Tu, Wenshao

    2016-01-01

    Abstract Tricyclic antidepressant amitriptyline (AM) has been shown to exert neurotrophic activity on neurons. We thus explored whether AM may aid the neuronal development and protect anesthesia-induced neuro-injury in young spinal cord dorsal root ganglion (DRG) neurons. The DRG explants were prepared from 1-day-old rats. The effect of AM on aiding DRG neural development was examined by immunohistochemistry at dose-dependent manner. AM-induced changes in gene and protein expressions, and also phosphorylation states of tyrosine kinases receptor A (TrkA) and B (TrkB) in DRG, were examined by quantitative real-time polymerase chain reaction and western blot. The effect of AM on attenuating lidocaine-induced DRG neurodegeneration was examined by immunohistochemistry, and small interfering RNA (siRNA)-mediated TrkA/B down-regulation. Amitriptyline stimulated DRG neuronal development in dose-dependent manner, but exerted toxic effect at concentrations higher than 10 M. AM activated TrkA in DRG through phosphorylation, whereas it had little effect on TrkB-signaling pathway. AM reduced lidocaine-induced DRG neurodegeneration by regenerating neurites and growth cones. Moreover, the neuroprotection of AM on lidocaine-injured neurodegeneration was blocked by siRNA-mediated TrkA down-regulation, but not by TrkB down-regulation. Amitriptyline facilitated neuronal development and had protective effect on lidocaine-induced neurodegeneration, very likely through the activation of TrkA-signaling pathway in DRG. PMID:27149473

  17. Neuronal labeling patterns in the spinal cord of adult transgenic Zebrafish.

    PubMed

    Stil, Aurélie; Drapeau, Pierre

    2016-06-01

    We describe neuronal patterns in the spinal cord of adult zebrafish. We studied the distribution of cells and processes in the three spinal regions reported in the literature: the 8th vertebra used as a transection injury site, the 15th vertebra mainly used for motor cell recordings and also for crush injury, and the 24th vertebra used to record motor nerve activity. We used well-known transgenic lines in which expression of green fluorescent protein (GFP) is driven by promoters to hb9 and isl1 in motoneurons, alx/chx10 and evx1 interneurons, ngn1 in sensory neurons and olig2 in oligodendrocytes, as well as antibodies for neurons (HuC/D, NF and SV2) and glia (GFAP). In isl1:GFP fish, GFP-positive processes are retained in the upper part of ventral horns and two subsets of cell bodies are observed. The pattern of the transgene in hb9:GFP adults is more diffuse and fibers are present broadly through the adult spinal cord. In alx/chx10 and evx1 lines we respectively observed two and three different GFP-positive populations. Finally, the ngn1:GFP transgene identifies dorsal root ganglion and some cells in dorsal horns. Interestingly some GFP positive fibers in ngn1:GFP fish are located around Mauthner axons and their density seems to be related to a rostrocaudal gradient. Many other cell types have been described in embryos and need to be studied in adults. Our findings provide a reference for further studies on spinal cytoarchitecture. Combined with physiological, histological and pathological/traumatic approaches, these studies will help clarify the operation of spinal locomotor circuits of adult zebrafish. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 642-660, 2016. PMID:26408263

  18. The maintenance of specific aspects of neuronal function and behavior is dependent on programmed cell death of adult-generated neurons in the dentate gyrus

    PubMed Central

    Kim, Woon Ryoung; Park, Ok-hee; Choi, Sukwoo; Choi, Se-Young; Park, Soon Kwon; Lee, Kea Joo; Rhyu, Im Joo; Kim, Hyun; Lee, Yeon Kyung; Kim, Hyun Taek; Oppenheim, Ronald W; Sun, Woong

    2009-01-01

    A considerable number of new neurons are generated daily in the dentate gyrus (DG) of the adult hippocampus, but only a subset of these survive, as many adult-generated neurons undergo programmed cell death (PCD). However, the significance of PCD in the adult brain for the functionality of DG circuits is not known. Here we examined the electrophysiological and behavioral characteristics of Bax-KO mice in which PCD of post-mitotic neurons is prevented. The continuous increase in DG cell numbers in Bax-KO mice, resulted in the readjustment of afferent and efferent synaptic connections, represented by age-dependent reductions in the dendritic arborization of DG neurons and in the synaptic contact ratio of mossy fibers (MF) with CA3 dendritic spines. These neuroanatomical changes were associated with reductions in synaptic transmission and reduced performance in a contextual fear memory task in 6-month old Bax-KO mice. These results suggest that the elimination of excess DG neurons via Bax-dependent PCD in the adult brain is required for the normal organization and function of the hippocampus. PMID:19519627

  19. Age-Related Phasic Patterns of Mitochondrial Maintenance in Adult Caenorhabditis elegans Neurons

    PubMed Central

    Morsci, Natalia S.; Hall, David H.

    2016-01-01

    Aging is associated with cognitive decline and increasing risk of neurodegeneration. Perturbation of mitochondrial function, dynamics, and trafficking are implicated in the pathogenesis of several age-associated neurodegenerative diseases. Despite this fundamental importance, the critical understanding of how organismal aging affects lifetime neuronal mitochondrial maintenance remains unknown, particularly in a physiologically relevant context. To address this issue, we performed a comprehensive in vivo analysis of age-associated changes in mitochondrial morphology, density, trafficking, and stress resistance in individual Caenorhabditis elegans neurons throughout adult life. Adult neurons display three distinct stages of increase, maintenance, and decrease in mitochondrial size and density during adulthood. Mitochondrial trafficking in the distal neuronal processes declines progressively with age starting from early adulthood. In contrast, long-lived daf-2 mutants exhibit delayed age-associated changes in mitochondrial morphology, constant mitochondrial density, and maintained trafficking rates during adulthood. Reduced mitochondrial load at late adulthood correlates with decreased mitochondrial resistance to oxidative stress. Revealing aging-associated changes in neuronal mitochondria in vivo is an essential precedent that will allow future elucidation of the mechanistic causes of mitochondrial aging. Thus, our study establishes the critical foundation for the future analysis of cellular pathways and genetic and pharmacological factors regulating mitochondrial maintenance in aging- and disease-relevant conditions. SIGNIFICANCE STATEMENT Using Caenorhabditis elegans as a model, we address long-standing questions: How does aging affect neuronal mitochondrial morphology, density, trafficking, and oxidative stress resistance? Are these age-related changes amenable to genetic manipulations that slow down the aging process? Our study illustrates that mitochondrial

  20. Conditional Reduction of Adult Born Doublecortin-Positive Neurons Reversibly Impairs Selective Behaviors

    PubMed Central

    Garrett, Lillian; Zhang, Jingzhong; Zimprich, Annemarie; Niedermeier, Kristina M.; Fuchs, Helmut; Gailus-Durner, Valerie; Hrabě de Angelis, Martin; Vogt Weisenhorn, Daniela; Wurst, Wolfgang; Hölter, Sabine M.

    2015-01-01

    Adult neurogenesis occurs in the adult mammalian subventricular zone (SVZ) along the walls of the lateral ventricles and the subgranular zone (SGZ) of the hippocampal dentate gyrus. While a burgeoning body of research implicates adult neurogenesis in olfactory bulb (OB)- and hippocampal-related behaviors, the precise function continues to elude. To further assess the behavioral importance of adult neurogenesis, we herein generated a novel inducible transgenic mouse model of adult neurogenesis reduction where mice with CreERT2 under doublecortin (DCX) promoter control were crossed with mice where diphtheria toxin A (DTA) was driven by the Rosa26 promoter. Activation of DTA, through the administration of tamoxifen (TAM), results in a specific reduction of DCX+ immature neurons in both the hippocampal dentate gyrus and OB. We show that the decrease of DCX+ cells causes impaired social discrimination ability in both young adult (from 3 months) and middle aged (from 10 months) mice. Furthermore, these animals showed an age-independent altered coping behavior in the Forced Swim Test without clear changes in anxiety-related behavior. Notably, these behavior changes were reversible on repopulating the neurogenic zones with DCX+ cells on cessation of the TAM treatment, demonstrating the specificity of this effect. Overall, these results support the notion that adult neurogenesis plays a role in social memory and in stress coping but not necessarily in anxiety-related behavior. PMID:26617501

  1. Genetic manipulation of adult-born hippocampal neurons rescues memory in a mouse model of Alzheimer's disease.

    PubMed

    Richetin, Kevin; Leclerc, Clémence; Toni, Nicolas; Gallopin, Thierry; Pech, Stéphane; Roybon, Laurent; Rampon, Claire

    2015-02-01

    In adult mammals, neural progenitors located in the dentate gyrus retain their ability to generate neurons and glia throughout lifetime. In rodents, increased production of new granule neurons is associated with improved memory capacities, while decreased hippocampal neurogenesis results in impaired memory performance in several memory tasks. In mouse models of Alzheimer's disease, neurogenesis is impaired and the granule neurons that are generated fail to integrate existing networks. Thus, enhancing neurogenesis should improve functional plasticity in the hippocampus and restore cognitive deficits in these mice. Here, we performed a screen of transcription factors that could potentially enhance adult hippocampal neurogenesis. We identified Neurod1 as a robust neuronal determinant with the capability to direct hippocampal progenitors towards an exclusive granule neuron fate. Importantly, Neurod1 also accelerated neuronal maturation and functional integration of new neurons during the period of their maturation when they contribute to memory processes. When tested in an APPxPS1 mouse model of Alzheimer's disease, directed expression of Neurod1 in cycling hippocampal progenitors conspicuously reduced dendritic spine density deficits on new hippocampal neurons, to the same level as that observed in healthy age-matched control animals. Remarkably, this population of highly connected new neurons was sufficient to restore spatial memory in these diseased mice. Collectively our findings demonstrate that endogenous neural stem cells of the diseased brain can be manipulated to become new neurons that could allow cognitive improvement. PMID:25518958

  2. The role of miR-146a in dorsal root ganglia neurons of experimental diabetic peripheral neuropathy.

    PubMed

    Wang, L; Chopp, M; Szalad, A; Zhang, Y; Wang, X; Zhang, R L; Liu, X S; Jia, L; Zhang, Z G

    2014-02-14

    Sensory neurons mediate diabetic peripheral neuropathy. Using a mouse model of diabetic peripheral neuropathy (BKS.Cg-m+/+Lepr(db)/J (db/db) mice) and cultured dorsal root ganglion (DRG) neurons, the present study showed that hyperglycemia downregulated miR-146a expression and elevated interleukin-1 receptor-activated kinase (IRAK1) and tumor necrosis factor receptor-associated factor 6 (TRAF6) levels in DRG neurons. In vitro, elevation of miR-146a by miR-146a mimics in DRG neurons increased neuronal survival under high-glucose conditions. Downregulation and elevation of miR-146a in DRG neurons, respectively, were inversely related to IRAK1 and TRAF6 levels. Treatment of diabetic peripheral neuropathy with sildenafil, a phosphodiesterase type 5 inhibitor, augmented miR-146a expression and decreased levels of IRAK1 and TRAF6 in the DRG neurons. In vitro, blockage of miR-146a in DRG neurons abolished the effect of sildenafil on DRG neuron protection and downregulation of IRAK1 and TRAF6 proteins under hyperglycemia. Our data provide the first evidence showing that miR-146a plays an important role in mediating DRG neuron apoptosis under hyperglycemic conditions. PMID:24316060

  3. Inhibitory neuron transplantation into adult visual cortex creates a new critical period that rescues impaired vision

    PubMed Central

    Davis, Melissa F.; Figueroa Velez, Dario X.; Guevarra, Roblen P.; Yang, Michael C.; Habeeb, Mariyam; Carathedathu, Mathew C.; Gandhi, Sunil P.

    2015-01-01

    The maturation of inhibitory circuits in the juvenile cortex triggers a critical period of plasticity in visual system development. Although several manipulations of inhibition can alter its timing, none have reactivated critical period plasticity in adulthood. We developed a transplantation method to reactivate critical period plasticity in the adult visual cortex. Transplanted embryonic inhibitory neurons from the medial ganglionic eminence reinstate ocular dominance plasticity in adult recipients. Transplanted inhibitory cells develop cell-type appropriate molecular characteristics and visually evoked responses. In adult mice impaired by deprivation during the juvenile critical period, transplantation also recovers both visual cortical responses and performance on a behavioral test of visual acuity. Plasticity and recovery are induced when the critical period would have occurred in the donor animal. These results reveal that the focal reactivation of visual cortical plasticity using inhibitory cell transplantation creates a new critical period that restores visual perception after childhood deprivation. PMID:25937171

  4. Is there a relationship between adult neurogenesis and neuron generation following injury across evolution?

    PubMed

    Ferretti, Patrizia

    2011-09-01

    All vertebrates can produce new neurons postnatally in discrete regions of their nervous system, but only some lower vertebrates (fish and amphibians) can significantly repair several neural structures, including brain, spinal cord, retina, olfactory and auditory-vestibular system, to compensate for neural tissue loss and recover significant functionality. Some regenerative ability, however, is found also in reptiles and birds, and even in mammals. The recognition that neurogenesis indeed occurs in the CNS of all adult vertebrates challenges the view that there is a simple relationship between maintenance of neurogenic regions in the adult CNS and regenerative capability. The aim of this review is to revisit this relationship in the light of recent literature focusing on selected examples of neurogenesis and regeneration, and discuss possible frameworks that may help to elucidate the relationship between adult neurogenesis and regeneration. This could provide useful paradigms for harnessing regeneration in the human CNS. PMID:21929627

  5. Knockout of Atg5 delays the maturation and reduces the survival of adult-generated neurons in the hippocampus

    PubMed Central

    Xi, Y; Dhaliwal, J S; Ceizar, M; Vaculik, M; Kumar, K L; Lagace, D C

    2016-01-01

    Autophagy is an evolutionarily conserved lysosomal degradation pathway that plays important roles in cell maintenance, expansion and differentiation. Removal of genes essential for autophagy from embryonic neural stem and precursor cells reduces the survival and inhibits neuronal differentiation of adult-generated neurons. No study has modified autophagy within the adult precursor cells, leaving the cell-autonomous role of autophagy in adult neurogenesis unknown. Here we demonstrate that autophagic flux exists in the adult dividing progenitor cells and their progeny in the dentate gyrus. To investigate the role of autophagy in adult hippocampal neurogenesis, we genetically deleted Autophagy-related gene 5 (Atg5) that reduced autophagic flux and the survival of the progeny of dividing progenitor cells. This significant reduction in survival of adult-generated neurons is accompanied by a delay in neuronal maturation, including a transient reduction in spine density in the absence of a change in differentiation. The delay in cell maturation and loss of progeny of the Atg5-null cells was not present in mice that lacked the essential pro-apoptotic protein Bax (Bcl-2-associated X protein), suggesting that Atg5-deficient cells die through a Bax-dependent mechanism. In addition, there was a loss of Atg5-null cells following exposure to running, suggesting that Atg5 is required for running-induced increases in neurogenesis. These findings highlight the cell-autonomous requirement of Atg5 in the survival of adult-generated neurons. PMID:26938300

  6. Characterization and isolation of immature neurons of the adult mouse piriform cortex.

    PubMed

    Rubio, A; Belles, M; Belenguer, G; Vidueira, S; Fariñas, I; Nacher, J

    2016-07-01

    Physiological studies indicate that the piriform or primary olfactory cortex of adult mammals exhibits a high degree of synaptic plasticity. Interestingly, a subpopulation of cells in the layer II of the adult piriform cortex expresses neurodevelopmental markers, such as the polysialylated form of neural cell adhesion molecule (PSA-NCAM) or doublecortin (DCX). This study analyzes the nature, origin, and potential function of these poorly understood cells in mice. As previously described in rats, most of the PSA-NCAM expressing cells in layer II could be morphologically classified as tangled cells and only a small proportion of larger cells could be considered semilunar-pyramidal transitional neurons. Most were also immunoreactive for DCX, confirming their immature nature. In agreement with this, detection of PSA-NCAM combined with that of different cell lineage-specific antigens revealed that most PSA-NCAM positive cells did not co-express markers of glial cells or mature neurons. Their time of origin was evaluated by birthdating experiments with halogenated nucleosides performed at different developmental stages and in adulthood. We found that virtually all cells in this paleocortical region, including PSA-NCAM-positive cells, are born during fetal development. In addition, proliferation analyses in adult mice revealed that very few cells were cycling in layer II of the piriform cortex and that none of them was PSA-NCAM-positive. Moreover, we have established conditions to isolate and culture these immature neurons in the adult piriform cortex layer II. We find that although they can survive under certain conditions, they do not proliferate in vitro either. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 748-763, 2016. PMID:26487449

  7. New neurons in the adult brain: The role of sleep and consequences of sleep loss

    PubMed Central

    Meerlo, Peter; Mistlberger, Ralph E.; Jacobs, Barry L.; Heller, H. Craig; McGinty, Dennis

    2009-01-01

    Research over the last few decades has firmly established that new neurons are generated in selected areas of the adult mammalian brain, particularly the dentate gyrus of the hippocampal formation and the subventricular zone of the lateral ventricles. The function of adult-born neurons is still a matter of debate. In the case of the hippocampus, integration of new cells in to the existing neuronal circuitry may be involved in memory processes and the regulation of emotionality. In recent years, various studies have examined how the production of new cells and their development into neurons is affected by sleep and sleep loss. While disruption of sleep for a period shorter than one day appears to have little effect on the basal rate of cell proliferation, prolonged restriction or disruption of sleep may have cumulative effects leading to a major decrease in hippocampal cell proliferation, cell survival and neurogenesis. Importantly, while short sleep deprivation may not affect the basal rate of cell proliferation, one study in rats shows that even mild sleep restriction may interfere with the increase in neurogenesis that normally occurs with hippocampus-dependent learning. Since sleep deprivation also disturbs memory formation, these data suggest that promoting survival, maturation and integration of new cells may be an unexplored mechanism by which sleep supports learning and memory processes. Most methods of sleep deprivation that have been employed affect both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. Available data favor the hypothesis that decreases in cell proliferation are related to a reduction in REM sleep, whereas decreases in the number of cells that subsequently develop into adult neurons may be related to reductions in both NREM and REM sleep. The mechanisms by which sleep loss affects different aspects of adult neurogenesis are unknown. It has been proposed that adverse effects of sleep disruption may be mediated by stress and

  8. Maternal immune activation differentially impacts mature and adult-born hippocampal neurons in male mice.

    PubMed

    Zhang, Zhi; van Praag, Henriette

    2015-03-01

    Schizophrenia is associated with deficits in the hippocampus, a brain area important for learning and memory. The dentate gyrus (DG) of the hippocampus develops both before and after birth. To study the relative contribution of mature and adult-born DG granule cells to disease etiology, we compared both cell populations in a mouse model of psychiatric illness resulting from maternal immune activation. Polyriboinosinic-polyribocytidilic acid (PolyIC, 5mg/kg) or saline was given on gestation day 15 to pregnant female C57Bl/6 mice. Male offspring (n=105), was administered systemic bromodeoxyuridine (BrdU, 50mg/kg) (n=52) or intracerebral retroviral injection into the DG (n=53), to label dividing cells at one month of age. Two months later behavioral tests were performed to evaluate disease phenotype. Immunohistochemistry and whole-cell patch clamping were used to assess morphological and physiological characteristics of DG cells. Three-month-old PolyIC exposed male offspring exhibited deficient pre-pulse inhibition, spatial maze performance and motor coordination, as well as increased depression-like behavior. Histological analysis showed reduced DG volume and parvalbumin positive interneuron number. Both mature and new hippocampal neurons showed modifications in intrinsic properties such as increased input resistance and lower current threshold, and decreased action potential number. Reduced GABAergic inhibitory transmission was observed only in mature DG neurons. Differential impairments in mature DG cells and adult-born new neurons may have implications for behavioral deficits associated with maternal immune activation. PMID:25449671

  9. Contrasting roles for parvalbumin-expressing inhibitory neurons in two forms of adult visual cortical plasticity

    PubMed Central

    Kaplan, Eitan S; Cooke, Sam F; Komorowski, Robert W; Chubykin, Alexander A; Thomazeau, Aurore; Khibnik, Lena A; Gavornik, Jeffrey P; Bear, Mark F

    2016-01-01

    The roles played by cortical inhibitory neurons in experience-dependent plasticity are not well understood. Here we evaluate the participation of parvalbumin-expressing (PV+) GABAergic neurons in two forms of experience-dependent modification of primary visual cortex (V1) in adult mice: ocular dominance (OD) plasticity resulting from monocular deprivation and stimulus-selective response potentiation (SRP) resulting from enriched visual experience. These two forms of plasticity are triggered by different events but lead to a similar increase in visual cortical response. Both also require the NMDA class of glutamate receptor (NMDAR). However, we find that PV+ inhibitory neurons in V1 play a critical role in the expression of SRP and its behavioral correlate of familiarity recognition, but not in the expression of OD plasticity. Furthermore, NMDARs expressed within PV+ cells, reversibly inhibited by the psychotomimetic drug ketamine, play a critical role in SRP, but not in the induction or expression of adult OD plasticity. DOI: http://dx.doi.org/10.7554/eLife.11450.001 PMID:26943618

  10. Transcription factors FOXA1 and FOXA2 maintain dopaminergic neuronal properties and control feeding behavior in adult mice.

    PubMed

    Pristerà, Alessandro; Lin, Wei; Kaufmann, Anna-Kristin; Brimblecombe, Katherine R; Threlfell, Sarah; Dodson, Paul D; Magill, Peter J; Fernandes, Cathy; Cragg, Stephanie J; Ang, Siew-Lan

    2015-09-01

    Midbrain dopaminergic (mDA) neurons are implicated in cognitive functions, neuropsychiatric disorders, and pathological conditions; hence understanding genes regulating their homeostasis has medical relevance. Transcription factors FOXA1 and FOXA2 (FOXA1/2) are key determinants of mDA neuronal identity during development, but their roles in adult mDA neurons are unknown. We used a conditional knockout strategy to specifically ablate FOXA1/2 in mDA neurons of adult mice. We show that deletion of Foxa1/2 results in down-regulation of tyrosine hydroxylase, the rate-limiting enzyme of dopamine (DA) biosynthesis, specifically in dopaminergic neurons of the substantia nigra pars compacta (SNc). In addition, DA synthesis and striatal DA transmission were reduced after Foxa1/2 deletion. Furthermore, the burst-firing activity characteristic of SNc mDA neurons was drastically reduced in the absence of FOXA1/2. These molecular and functional alterations lead to a severe feeding deficit in adult Foxa1/2 mutant mice, independently of motor control, which could be rescued by L-DOPA treatment. FOXA1/2 therefore control the maintenance of molecular and physiological properties of SNc mDA neurons and impact on feeding behavior in adult mice. PMID:26283356

  11. Adult Conditional Knockout of PGC-1α Leads to Loss of Dopamine Neurons.

    PubMed

    Jiang, Haisong; Kang, Sung-Ung; Zhang, Shuran; Karuppagounder, Senthilkumar; Xu, Jinchong; Lee, Yong-Kyu; Kang, Bong-Gu; Lee, Yunjong; Zhang, Jianmin; Pletnikova, Olga; Troncoso, Juan C; Pirooznia, Shelia; Andrabi, Shaida A; Dawson, Valina L; Dawson, Ted M

    2016-01-01

    Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder. Recent studies have implicated a role for peroxisome proliferator-activated receptor γ coactivator protein-1α (PGC-1α) in PD and in animal or cellular models of PD. The role of PGC-1α in the function and survival of substantia nigra pars compacta (SNpc) dopamine neurons is not clear. Here we find that there are four different PGC-1α isoforms expressed in SH-SY5Y cells, and these four isoforms are expressed across subregions of mouse brain. Adult conditional PGC-1α knock-out mice show a significant loss of dopaminergic neurons that is accompanied by a reduction of dopamine in the striatum. In human PD postmortem tissue from the SNpc, there is a reduction of PGC-1α isoforms and mitochondria markers. Our findings suggest that all four isoforms of PGC-1α are required for the proper expression of mitochondrial proteins in SNpc DA neurons and that PGC-1α is essential for SNpc DA neuronal survival, possibly through the maintenance of mitochondrial function. PMID:27622213

  12. Adult Conditional Knockout of PGC-1α Leads to Loss of Dopamine Neurons

    PubMed Central

    Jiang, Haisong; Zhang, Shuran; Karuppagounder, Senthilkumar; Xu, Jinchong; Pletnikova, Olga; Troncoso, Juan C.; Pirooznia, Shelia; Andrabi, Shaida A.

    2016-01-01

    Parkinson’s disease (PD) is a chronic progressive neurodegenerative disorder. Recent studies have implicated a role for peroxisome proliferator-activated receptor γ coactivator protein-1α (PGC-1α) in PD and in animal or cellular models of PD. The role of PGC-1α in the function and survival of substantia nigra pars compacta (SNpc) dopamine neurons is not clear. Here we find that there are four different PGC-1α isoforms expressed in SH-SY5Y cells, and these four isoforms are expressed across subregions of mouse brain. Adult conditional PGC-1α knock-out mice show a significant loss of dopaminergic neurons that is accompanied by a reduction of dopamine in the striatum. In human PD postmortem tissue from the SNpc, there is a reduction of PGC-1α isoforms and mitochondria markers. Our findings suggest that all four isoforms of PGC-1α are required for the proper expression of mitochondrial proteins in SNpc DA neurons and that PGC-1α is essential for SNpc DA neuronal survival, possibly through the maintenance of mitochondrial function. PMID:27622213

  13. Carbachol-Induced Reduction in the Activity of Adult Male Zebra Finch RA Projection Neurons

    PubMed Central

    Meng, Wei; Wang, Song-Hua; Li, Dong-Feng

    2016-01-01

    Cholinergic mechanism is involved in motor behavior. In songbirds, the robust nucleus of the arcopallium (RA) is a song premotor nucleus in the pallium and receives cholinergic inputs from the basal forebrain. The activity of projection neurons in RA determines song motor behavior. Although many evidences suggest that cholinergic system is implicated in song production, the cholinergic modulation of RA is not clear until now. In the present study, the electrophysiological effects of carbachol, a nonselective cholinergic receptor agonist, were investigated on the RA projection neurons of adult male zebra finches through whole-cell patch-clamp techniques in vitro. Our results show that carbachol produced a significant decrease in the spontaneous and evoked action potential (AP) firing frequency of RA projection neurons, accompanying a hyperpolarization of the membrane potential, an increase in the evoked AP latency, afterhyperpolarization (AHP) peak amplitude, and AHP time to peak, and a decrease in the membrane input resistance, membrane time constant, and membrane capacitance. These results indicate that carbachol reduces the activity of RA projection neurons by hyperpolarizing the resting membrane potential and increasing the AHP and the membrane conductance, suggesting that the cholinergic modulation of RA may play an important role in song production. PMID:26904300

  14. Young, active and well-connected: adult-born neurons in the zebra finch are activated during singing.

    PubMed

    Tokarev, Kirill; Boender, Arjen J; Claßen, Gala A E; Scharff, Constance

    2016-05-01

    Neuronal replacement in the pallial song control nucleus HVC of adult zebra finches constitutes an interesting case of homeostatic plasticity; in spite of continuous addition and attrition of neurons in ensembles that code song elements, adult song remains remarkably invariant. New neurons migrate into HVC and later synapse with their target, arcopallial song nucleus RA (HVCRA). New HVCRA neurons respond to auditory stimuli (in anaesthetised animals), but whether and when they become functionally active during singing is unknown. We studied this, using 5-bromo-2'-deoxyuridine to birth-date neurons, combined with immunohistochemical detection of immediate-early gene (IEG) expression and retrograde tracer injections into RA to track connectivity. Interestingly, singing was followed by IEG expression in a substantial fraction of new neurons that were not retrogradely labelled from RA, suggesting a possible role in HVC-intrinsic network function. As new HVC neurons matured, the proportion of HVCRA neurons that expressed IEGs after singing increased significantly. Since it was previously shown that singing induces IEG expression in HVC also in deaf birds and that hearing song does not induce IEG expression in HVC, our data provide the first direct evidence that new HVC neurons are engaged in song motor behaviour. PMID:25687260

  15. Rabies virus infection of primary neuronal cultures and adult mice: failure to demonstrate evidence of excitotoxicity.

    PubMed

    Weli, Simon C; Scott, Courtney A; Ward, Christopher A; Jackson, Alan C

    2006-10-01

    Cultures derived from the cerebral cortices and hippocampi of 17-day-old mouse fetuses infected with the CVS strain of rabies virus showed loss of trypan blue exclusion, morphological apoptotic features, and activated caspase 3 expression, indicating apoptosis. The NMDA (N-methyl-D-aspartate acid) antagonists ketamine (125 microM) and MK-801 (60 microM) were found to have no significant neuroprotective effect on CVS-infected neurons, while the caspase inhibitor Ac-Asp-Glu-Val aspartic acid aldehyde (25 microM) exerted a marked neuroprotective effect. Glutamate-stimulated increases in levels of intracellular calcium were reduced in CVS-infected hippocampal neurons. Ketamine (120 mg/kg of body weight/day intraperitoneally) given to CVS-infected adult mice produced no beneficial effects. We have found no supportive evidence that excitotoxicity plays an important role in rabies virus infection. PMID:17005706

  16. Inducible neuronal inactivation of Sim1 in adult mice causes hyperphagic obesity.

    PubMed

    Tolson, Kristen P; Gemelli, Terry; Meyer, Donna; Yazdani, Umar; Kozlitina, Julia; Zinn, Andrew R

    2014-07-01

    Germline haploinsufficiency of human or mouse Sim1 is associated with hyperphagic obesity. Sim1 encodes a transcription factor required for proper formation of the paraventricular (PVN), supraoptic, and anterior periventricular hypothalamic nuclei. Sim1 expression persists in these neurons in adult mice, raising the question of whether it plays a physiologic role in regulation of energy balance. We previously showed that Sim1 heterozygous mice had normal numbers of PVN neurons that were hyporesponsive to melanocortin 4 receptor agonism and showed reduced oxytocin expression. Furthermore, conditional postnatal neuronal inactivation of Sim1 also caused hyperphagic obesity and decreased hypothalamic oxytocin expression. PVN projections to the hindbrain, where oxytocin is thought to act to modulate satiety, were anatomically intact in both Sim1 heterozygous and conditional knockout mice. These experiments provided evidence that Sim1 functions in energy balance apart from its role in hypothalamic development but did not rule out effects of Sim1 deficiency on postnatal hypothalamic maturation. To address this possibility, we used a tamoxifen-inducible, neural-specific Cre transgene to conditionally inactivate Sim1 in adult mice with mature hypothalamic circuitry. Induced Sim1 inactivation caused increased food and water intake and decreased expression of PVN neuropeptides, especially oxytocin and vasopressin, with no change in energy expenditure. Sim1 expression was not required for survival of PVN neurons. The results corroborate previous evidence that Sim1 acts physiologically as well as developmentally to regulate body weight. Inducible knockout mice provide a system for studying Sim1's physiologic function in energy balance and identifying its relevant transcriptional targets in the hypothalamus. PMID:24773343

  17. Fragile X Mental Retardation Protein Regulates New Neuron Differentiation in the Adult Olfactory Bulb

    PubMed Central

    Scotto-Lomassese, Sophie; Nissant, Antoine; Mota, Tatiana; Néant-Féry, Marie; Oostra, Ben A.; Greer, Charles A.; Lledo, Pierre-Marie; Trembleau, Alain; Caillé, Isabelle

    2013-01-01

    The fragile X mental retardation protein (FMRP) is an RNA-binding protein essential for multiple aspects of neuronal mRNA metabolism. Its absence leads to the fragile X syndrome, the most prevalent genetic form of mental retardation. The anatomical landmark of the disease, also present in the Fmr1 knock-out (KO) mice, is the hyperabundance of immature-looking lengthened dendritic spines. We used the well known continuous production of adult-born granule cells (GCs) in the mouse olfactory bulb (OB) to analyze the consequences of Fmrp loss on the differentiation of GCs. Morphological analysis of GCs in the Fmr1 KO mice showed an increase in spine density without a change in spine length. We developed an RNA interference strategy to cell-autonomously mutate Fmr1 in a wild-type OB network. Mutated GCs displayed an increase in spine density and spine length. Detailed analysis of the spines through immunohistochemistry, electron microscopy, and electrophysiology surprisingly showed that, despite these abnormalities, spines receive normal glutamatergic synapses, and thus that mutated adult-born neurons are synaptically integrated into the OB circuitry. Time-course analysis of the spine defects showed that Fmrp cell-autonomously downregulates the level and rate of spine production and limits their overgrowth. Finally, we report that Fmrp does not regulate dendritogenesis in standard conditions but is necessary for activity-dependent dendritic remodeling. Overall, our study of Fmrp in the context of adult neurogenesis has enabled us to carry out a precise dissection of the role of Fmrp in neuronal differentiation and underscores its pleiotropic involvement in both spinogenesis and dendritogenesis. PMID:21307257

  18. Critical appraisal of the DRG system: problem areas for DRG reimbursement in the USA.

    PubMed

    Harper, D L

    1985-03-01

    One may conclude that the prospective payment system known as Diagnosis Related Groups is the initial thrust of the government to reduce the rate of expenditures for Medicare patients in the acute hospital setting. More will come and probably soon. Among the criticism and concern, one must not ignore the non-inclusion of the physician provider in this system. Cost shifting to the private payer will probably result in DRGs in that area also. Concern about the ability to provide the technology necessary to render quality care is utmost on the minds of providers. The shift of patients into the alternate health care field will leave hospitals with fewer patients who are overall much sicker and the hospital will have fewer dollars from which to provide that care. There is specific criticism of some of the DRG groupings and concern with the way in which physicians will be brought under the system. The issue of bad debts and care for the indigent must be addressed. A great deal of attention must be paid in the manner in which capital costs are reimbursed. Medical education costs must be satisfactorily addressed on a national basis. MEDPAR data used to provide data base for determining the DRG rates, must be upgraded to bring fairness to the system. Now medical technology must be examined quickly and the costs of those desirable technological advances incorporated into the DRG rate so as not to impede their use. Perhaps the greatest concern relates to the factors which will be incorporated into the rate basis and those which affect the allowable rate increases.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3929757

  19. Sex and laterality differences in medial amygdala neurons and astrocytes of adult mice.

    PubMed

    Pfau, Daniel R; Hobbs, Nicholas J; Breedlove, S Marc; Jordan, Cynthia L

    2016-08-15

    The posterodorsal aspect of the medial amygdala (MePD) in rats is sexually dimorphic, being larger and containing more and larger neurons in males than in females. It is also highly lateralized, with the right MePD larger than the left in both sexes, but with the smaller left MePD actually containing more and larger neurons than the larger right. Astrocytes are also strikingly sexually differentiated, with male-biased numbers and lateralized favoring the right in the rat MePD. However, comparable information is scant for mice where genetic tools offer greater experimental power. Hence, we examined the MePD from adult male and female C57Bl/6(J) mice. We now report that the MePD is larger in males than in females, with the MePD in males containing more astrocytes and neurons than in females. However, we did not find sex differences in astrocyte complexity or overall glial number nor effects of laterality in either measure. While the mouse MePD is generally less lateralized than in rats, we did find that the sex difference in astrocyte number is only on the right because of a significant lateralization in females, with significantly fewer astrocytes on the right than the left but only in females. A sex difference in neuronal soma size favoring males was also evident, but only on the left. Sex differences in the number of neurons and astrocytes common to both rodent species may represent core morphological features that critically underlie the expression of sex-specific behaviors that depend on the MePD. J. Comp. Neurol. 524:2492-2502, 2016. © 2016 Wiley Periodicals, Inc. PMID:26780286

  20. The Role of Astrocytes in the Generation, Migration, and Integration of New Neurons in the Adult Olfactory Bulb

    PubMed Central

    Gengatharan, Archana; Bammann, Rodrigo R.; Saghatelyan, Armen

    2016-01-01

    In mammals, new neurons in the adult olfactory bulb originate from a pool of neural stem cells in the subventricular zone of the lateral ventricles. Adult-born cells play an important role in odor information processing by adjusting the neuronal network to changing environmental conditions. Olfactory bulb neurogenesis is supported by several non-neuronal cells. In this review, we focus on the role of astroglial cells in the generation, migration, integration, and survival of new neurons in the adult forebrain. In the subventricular zone, neural stem cells with astrocytic properties display regional and temporal specificity when generating different neuronal subtypes. Non-neurogenic astrocytes contribute to the establishment and maintenance of the neurogenic niche. Neuroblast chains migrate through the rostral migratory stream ensheathed by astrocytic processes. Astrocytes play an important regulatory role in neuroblast migration and also assist in the development of a vasculature scaffold in the migratory stream that is essential for neuroblast migration in the postnatal brain. In the olfactory bulb, astrocytes help to modulate the network through a complex release of cytokines, regulate blood flow, and provide metabolic support, which may promote the integration and survival of new neurons. Astrocytes thus play a pivotal role in various processes of adult olfactory bulb neurogenesis, and it is likely that many other functions of these glial cells will emerge in the near future. PMID:27092050

  1. The Role of Astrocytes in the Generation, Migration, and Integration of New Neurons in the Adult Olfactory Bulb.

    PubMed

    Gengatharan, Archana; Bammann, Rodrigo R; Saghatelyan, Armen

    2016-01-01

    In mammals, new neurons in the adult olfactory bulb originate from a pool of neural stem cells in the subventricular zone of the lateral ventricles. Adult-born cells play an important role in odor information processing by adjusting the neuronal network to changing environmental conditions. Olfactory bulb neurogenesis is supported by several non-neuronal cells. In this review, we focus on the role of astroglial cells in the generation, migration, integration, and survival of new neurons in the adult forebrain. In the subventricular zone, neural stem cells with astrocytic properties display regional and temporal specificity when generating different neuronal subtypes. Non-neurogenic astrocytes contribute to the establishment and maintenance of the neurogenic niche. Neuroblast chains migrate through the rostral migratory stream ensheathed by astrocytic processes. Astrocytes play an important regulatory role in neuroblast migration and also assist in the development of a vasculature scaffold in the migratory stream that is essential for neuroblast migration in the postnatal brain. In the olfactory bulb, astrocytes help to modulate the network through a complex release of cytokines, regulate blood flow, and provide metabolic support, which may promote the integration and survival of new neurons. Astrocytes thus play a pivotal role in various processes of adult olfactory bulb neurogenesis, and it is likely that many other functions of these glial cells will emerge in the near future. PMID:27092050

  2. Protein kinase LKB1 regulates polarized dendrite formation of adult hippocampal newborn neurons.

    PubMed

    Huang, Wei; She, Liang; Chang, Xing-ya; Yang, Rong-rong; Wang, Liang; Ji, Hong-bin; Jiao, Jian-wei; Poo, Mu-ming

    2014-01-01

    Adult-born granule cells in the dentate gyrus of the rodent hippocampus are important for memory formation and mood regulation, but the cellular mechanism underlying their polarized development, a process critical for their incorporation into functional circuits, remains unknown. We found that deletion of the serine-threonine protein kinase LKB1 or overexpression of dominant-negative LKB1 reduced the polarized initiation of the primary dendrite from the soma and disrupted its oriented growth toward the molecular layer. This abnormality correlated with the dispersion of Golgi apparatus that normally accumulated at the base and within the initial segment of the primary dendrite, and was mimicked by disrupting Golgi organization via altering the expression of Golgi structural proteins GM130 or GRASP65. Thus, besides its known function in axon formation in embryonic pyramidal neurons, LKB1 plays an additional role in regulating polarized dendrite morphogenesis in adult-born granule cells in the hippocampus. PMID:24367100

  3. Insulin-like growth factor-1 inhibits adult supraoptic neurons via complementary modulation of mechanoreceptors and glycine receptors.

    PubMed

    Ster, Jeanne; Colomer, Claude; Monzo, Cécile; Duvoid-Guillou, Anne; Moos, Françoise; Alonso, Gérard; Hussy, Nicolas

    2005-03-01

    In the CNS, insulin-like growth factor-1 (IGF-1) is mainly known for its trophic effect both during development and in adulthood. Here, we show than in adult rat supraoptic nucleus (SON), IGF-1 receptor immunoreactivity is present in neurons, whereas IGF-1 immunoreactivity is found principally in astrocytes and more moderately in neurons. In vivo application of IGF-1 within the SON acutely inhibits the activity of both vasopressin and oxytocin neurons, the two populations of SON neuroendocrine cells. Recordings of acutely isolated SON neurons showed that this inhibition occurs through two rapid and reversible mechanisms, both involving the neuronal IGF-1 receptor but different intracellular messengers. IGF-1 inhibits Gd3+-sensitive and osmosensitive mechanoreceptor cation current via phosphatidylinositol-3 (PI3) kinase activation. IGF-1 also potentiates taurine-activated glycine receptor (GlyR) Cl- currents by increasing the agonist sensitivity through a extremely rapid (within a second) PI3 kinase-independent mechanism. Both mechanoreceptor channels and GlyR, which form the excitatory and inhibitory components of SON neuron osmosensitivity, are active at rest, and their respective inhibition and potentiation will both be inhibitory, leading to strong decrease in neuronal activity. It will be of interest to determine whether IGF-1 is released by neurons, thus participating in an inhibitory autocontrol, or astrocytes, then joining the growing family of glia-to-neuron transmitters that modulate neuronal and synaptic activity. Through the opposite and complementary acute regulation of mechanoreceptors and GlyR, IGF-1 appears as a new important neuromodulator in the adult CNS, participating in the complex integration of neural messages that regulates the level of neuronal excitability. PMID:15745952

  4. Exposure to Zinc Sulfate Results in Differential Effects on Olfactory Sensory Neuron Subtypes in Adult Zebrafish.

    PubMed

    Hentig, James T; Byrd-Jacobs, Christine A

    2016-01-01

    Zinc sulfate is a known olfactory toxicant, although its specific effects on the olfactory epithelium of zebrafish are unknown. Olfactory organs of adult zebrafish were exposed to zinc sulfate and, after 2, 3, 5, 7, 10 or 14 days, fish were processed for histological, immunohistochemical, ultrastructural, and behavioral analyses. Severe morphological disruption of the olfactory organ was observed two days following zinc sulfate exposure, including fusion of lamellae, epithelial inflammation, and significant loss of anti-calretinin labeling. Scanning electron microscopy revealed the apical surface of the sensory region was absent of ciliated structures, but microvilli were still present. Behavioral analysis showed significant loss of the ability to perceive bile salts and some fish also had no response to amino acids. Over the next several days, olfactory organ morphology, epithelial structure, and anti-calretinin labeling returned to control-like conditions, although the ability to perceive bile salts remained lost until day 14. Thus, exposure to zinc sulfate results in rapid degeneration of the olfactory organ, followed by restoration of morphology and function within two weeks. Zinc sulfate appears to have a greater effect on ciliated olfactory sensory neurons than on microvillous olfactory sensory neurons, suggesting differential effects on sensory neuron subtypes. PMID:27589738

  5. Ethanol-Induced Alterations in Purkinje Neuron Dendrites in Adult and Aging Rats: a Review.

    PubMed

    Dlugos, Cynthia A

    2015-08-01

    Uncomplicated alcoholics suffer from discrete motor dysfunctions that become more pronounced with age. These deficits involve the structure and function of Purkinje neurons (PN), the sole output neurons from the cerebellar cortex. This review focuses on alterations to the PN dendritic arbor in the adult and aging Fischer 344 rat following lengthy alcohol consumption. It describes seminal studies using the Golgi-Cox method which proposed a model for ethanol-induced dendritic regression. Subsequent ultrastructural studies of PN dendrites showed dilation of the extensive smooth endoplasmic reticulum (SER) which preceded and accompanied dendritic regression. The component of the SER that was most affected by ethanol was the sarco/endoplasmic reticulum Ca(2+) ATPase pump (SERCA) responsible for resequestration of calcium into the SER. Ethanol-induced decreases in SERCA pump levels, similar to the finding of SER dilation, preceded and occurred concomitantly with dendritic regression. Discrete ethanol-induced deficits in balance also accompanied these decreases. Ethanol-induced ER stress within the SER of PN dendrites was proposed as an underlying cause of dendritic regression. It was recently shown that increased activation of caspase 12, inherent to the ER, occurred in PN of acute slices in ethanol-fed rats and was most pronounced following 40 weeks of ethanol treatment. These findings shed new light into alcohol-induced disruption in PN dendrites providing a new model for the discrete but critical changes in motor function in aging, adult alcoholics. PMID:25648753

  6. From progenitors to integrated neurons: role of neurotransmitters in adult olfactory neurogenesis.

    PubMed

    Bovetti, Serena; Gribaudo, Simona; Puche, Adam C; De Marchis, Silvia; Fasolo, Aldo

    2011-12-01

    Adult neurogenesis is due to the persistence of pools of constitutive stem cells able to give rise to a progeny of proliferating progenitors. In rodents, adult neurogenic niches have been found in the subventricular zone (SVZ) along the lateral ventricles and in the subgranular zone of the dentate gyrus in the hippocampus. SVZ progenitors undergo a unique process of tangential migration from the lateral ventricle to the olfactory bulb (OB) where they differentiate mainly into GABAergic interneurons in the granule and glomerular layers. SVZ progenitor proliferation, migration and differentiation into fully integrated neurons, are strictly related processes regulated by complex interactions between cell intrinsic and extrinsic influences. Numerous observations demonstrate that neurotrasmitters are involved in all steps of the adult neurogenic process, but the understanding of their role is hampered by their intricate mechanism of action and by the highly complex network in which neurotransmitters work. By considering the three main steps of olfactory adult neurogenesis (proliferation, migration and integration), this review will discuss recent advances in the study of neurotransmitters, highlighting the regulatory mechanisms upstream and downstream their action. PMID:21641990

  7. Tau Pathology is Present In Vivo and Develops In Vitro in Sensory Neurons from Human P301S Tau Transgenic Mice: A System for Screening Drugs against Tauopathies

    PubMed Central

    Mellone, Manuela; Kestoras, Dimitra; Andrews, Melissa R.; Dassie, Elisa; Crowther, R. Anthony; Stokin, Gorazd B.; Tinsley, Jon; Horne, Graeme; Goedert, Michel

    2013-01-01

    Intracellular tau aggregates are the neuropathological hallmark of several neurodegenerative diseases, including Alzheimer's disease, progressive supranuclear palsy, and cases of frontotemporal dementia, but the link between these aggregates and neurodegeneration remains unclear. Neuronal models recapitulating the main features of tau pathology are necessary to investigate the molecular mechanisms of tau malfunction, but current models show little and inconsistent spontaneous tau aggregation. We show that dorsal root ganglion (DRG) neurons in transgenic mice expressing human P301S tau (P301S-htau) develop tau pathology similar to that found in brain and spinal cord and a significant reduction in mechanosensation occurs before detectable fibrillar tau formation. DRG neuronal cultures established from adult P301S-htau mice at different ages retained the pattern of aberrant tau found in vivo. Moreover, htau became progressively hyperphosphorylated over 2 months in vitro beginning with nonsymptomatic neurons, while hyperphosphorylated P301S-htau-positive neurons from 5-month-old mice cultured for 2 months died preferentially. P301S-htau-positive neurons grew aberrant axons, including spheroids, typically found in human tauopathies. Neurons cultured at advanced stages of tau pathology showed a 60% decrease in the fraction of moving mitochondria. SEG28019, a novel O-GlcNAcase inhibitor, reduced steady-state pSer396/pSer404 phosphorylation over 7 weeks in a significant proportion of DRG neurons showing for the first time the possible beneficial effect of prolonged dosing of O-GlcNAcase inhibitor in vitro. Our system is unique in that fibrillar tau forms without external manipulation and provides an important new tool for understanding the mechanisms of tau dysfunction and for screening of compounds for treatment of tauopathies. PMID:24227726

  8. Habitat-specific shaping of proliferation and neuronal differentiation in adult hippocampal neurogenesis of wild rodents

    PubMed Central

    Cavegn, Nicole; van Dijk, R. Maarten; Menges, Dominik; Brettschneider, Helene; Phalanndwa, Mashudu; Chimimba, Christian T.; Isler, Karin; Lipp, Hans-Peter; Slomianka, Lutz; Amrein, Irmgard

    2013-01-01

    Daily life of wild mammals is characterized by a multitude of attractive and aversive stimuli. The hippocampus processes complex polymodal information associated with such stimuli and mediates adequate behavioral responses. How newly generated hippocampal neurons in wild animals contribute to hippocampal function is still a subject of debate. Here, we test the relationship between adult hippocampal neurogenesis (AHN) and habitat types. To this end, we compare wild Muridae species of southern Africa [Namaqua rock mouse (Micaelamys namaquensis), red veld rat (Aethomys chrysophilus), highveld gerbil (Tatera brantsii), and spiny mouse (Acomys spinosissimus)] with data from wild European Muridae [long-tailed wood mice (Apodemus sylvaticus), pygmy field mice (Apodemus microps), yellow-necked wood mice (Apodemus flavicollis), and house mice (Mus musculus domesticus)] from previous studies. The pattern of neurogenesis, expressed in normalized numbers of Ki67- and Doublecortin(DCX)-positive cells to total granule cells (GCs), is similar for the species from a southern African habitat. However, we found low proliferation, but high neuronal differentiation in rodents from the southern African habitat compared to rodents from the European environment. Within the African rodents, we observe additional regulatory and morphological traits in the hippocampus. Namaqua rock mice with previous pregnancies showed lower AHN compared to males and nulliparous females. The phylogenetically closely related species (Namaqua rock mouse and red veld rat) show a CA4, which is not usually observed in murine rodents. The specific features of the southern environment that may be associated with the high number of young neurons in African rodents still remain to be elucidated. This study provides the first evidence that a habitat can shape adult neurogenesis in rodents across phylogenetic groups. PMID:23616743

  9. Abundance of gap junctions at glutamatergic mixed synapses in adult Mosquitofish spinal cord neurons

    PubMed Central

    Serrano-Velez, Jose L.; Rodriguez-Alvarado, Melanie; Torres-Vazquez, Irma I.; Fraser, Scott E.; Yasumura, Thomas; Vanderpool, Kimberly G.; Rash, John E.; Rosa-Molinar, Eduardo

    2014-01-01

    “Dye-coupling”, whole-mount immunohistochemistry for gap junction channel protein connexin 35 (Cx35), and freeze-fracture replica immunogold labeling (FRIL) reveal an abundance of electrical synapses/gap junctions at glutamatergic mixed synapses in the 14th spinal segment that innervates the adult male gonopodium of Western Mosquitofish, Gambusia affinis (Mosquitofish). To study gap junctions’ role in fast motor behavior, we used a minimally-invasive neural-tract-tracing technique to introduce gap junction-permeant or -impermeant dyes into deep muscles controlling the gonopodium of the adult male Mosquitofish, a teleost fish that rapidly transfers (complete in <20 mS) spermatozeugmata into the female reproductive tract. Dye-coupling in the 14th spinal segment controlling the gonopodium reveals coupling between motor neurons and a commissural primary ascending interneuron (CoPA IN) and shows that the 14th segment has an extensive and elaborate dendritic arbor and more gap junctions than do other segments. Whole-mount immunohistochemistry for Cx35 results confirm dye-coupling and show it occurs via gap junctions. Finally, FRIL shows that gap junctions are at mixed synapses and reveals that >50 of the 62 gap junctions at mixed synapses are in the 14th spinal segment. Our results support and extend studies showing gap junctions at mixed synapses in spinal cord segments involved in control of genital reflexes in rodents, and they suggest a link between mixed synapses and fast motor behavior. The findings provide a basis for studies of specific roles of spinal neurons in the generation/regulation of sex-specific behavior and for studies of gap junctions’ role in regulating fast motor behavior. Finally, the CoPA IN provides a novel candidate neuron for future studies of gap junctions and neural control of fast motor behaviors. PMID:25018700

  10. Birth, survival and differentiation of neurons in an adult crustacean brain.

    PubMed

    Kim, Youngmi Faith; Sandeman, David C; Benton, Jeanne L; Beltz, Barbara S

    2014-06-01

    Life-long neurogenesis is a characteristic feature of many vertebrate and invertebrate species. In decapod crustaceans, new neurons are added throughout life to two cell clusters containing local (cluster 9) and projection (cluster 10) interneurons in the olfactory pathway. Adult-born neurons in clusters 9 and 10 in crayfish have the anatomical properties and chemistry of mature neurons by 6 months after birth. Here we use 5-bromo-2'-deoxyuridine (BrdU) incorporation to pulse label mitotically active cells in these cell clusters, followed by a survival time of up to 8 months, during which crayfish (Cherax destructor) were sacrificed at intervals and the numbers of BrdU-labeled cells quantified. We find a decrease in the numbers of BrdU-labeled cells in cell cluster 10 between the first and second weeks following BrdU exposure, suggesting a period of cell death shortly after proliferation. Additional delayed cell divisions in both cell clusters are indicated by increases in labeled cells long after the BrdU clearing time. The differentiation time of these cells into neurons was defined by detection of the first immunoreactivity for the transmitter SIFamide in cluster 10 BrdU-labeled cells, which begins at 4 weeks after BrdU labeling; the numbers of SIFamide-labeled cells continues to increase over the following month. Experiments testing whether proliferation and survival of Cluster 10 cells are influenced by locomotor activity provided no evidence of a correlation between activity levels and cell proliferation, but suggest a strong influence of locomotor activity on cell survival. PMID:24339155

  11. Expression of Wnt Receptors in Adult Spiral Ganglion Neurons: Frizzled 9 Localization at Growth Cones of Regenerating Neurites

    PubMed Central

    Shah, S. M.; Kang, Y.-J.; Christensen, B. L.; Feng, A. S.; Kollmar, R.

    2009-01-01

    Little is known about signaling pathways, besides those of neurotrophic factors, that are operational in adult spiral ganglion neurons. In patients with sensorineural hearing loss, such pathways could eventually be targeted to stimulate and guide neurite outgrowth from the remnants of the spiral ganglion towards a cochlear implant, thereby improving the fidelity of sound transmission. To systematically identify neuronal receptors for guidance cues in the adult cochlea, we conducted a genome-wide cDNA microarray screen with two-month-old CBA/CaJ mice. A meta-analysis of our data and those from older mice in two other studies revealed the presence of neuronal transmembrane receptors that represent all four established guidance pathways—ephrin, netrin, semaphorin, and slit—in the mature cochlea as late as 15 months. In addition, we observed the expression of all known receptors for the Wnt morphogens, whose neuronal guidance function has only recently been recognized. In situ hybridizations located the mRNAs of the Wnt receptors frizzled 1, 4, 6, 9, and 10 specifically in adult spiral ganglion neurons. Finally, frizzled 9 protein was found in the growth cones of adult spiral ganglion neurons that were regenerating neurites in culture. We conclude from our results that adult spiral ganglion neurons are poised to respond to neurite damage, owing to the constitutive expression of a large and diverse collection of guidance receptors. Wnt signaling, in particular, emerges as a candidate pathway for guiding neurite outgrowth towards a cochlear implant after sensorineural hearing loss. PMID:19716861

  12. High yield extraction of pure spinal motor neurons, astrocytes and microglia from single embryo and adult mouse spinal cord

    PubMed Central

    Beaudet, Marie-Josée; Yang, Qiurui; Cadau, Sébastien; Blais, Mathieu; Bellenfant, Sabrina; Gros-Louis, François; Berthod, François

    2015-01-01

    Extraction of mouse spinal motor neurons from transgenic mouse embryos recapitulating some aspects of neurodegenerative diseases like amyotrophic lateral sclerosis has met with limited success. Furthermore, extraction and long-term culture of adult mouse spinal motor neurons and glia remain also challenging. We present here a protocol designed to extract and purify high yields of motor neurons and glia from individual spinal cords collected on embryos and adult (5-month-old) normal or transgenic mice. This method is based on mild digestion of tissue followed by gradient density separation allowing to obtain two millions motor neurons over 92% pure from one E14.5 single embryo and more than 30,000 from an adult mouse. These cells can be cultured more than 14 days in vitro at a density of 100,000 cells/cm2 to maintain optimal viability. Functional astrocytes and microglia and small gamma motor neurons can be purified at the same time. This protocol will be a powerful and reliable method to obtain motor neurons and glia to better understand mechanisms underlying spinal cord diseases. PMID:26577180

  13. Changes in cat medullary neurone firing rates and synchrony following induction of respiratory long-term facilitation

    PubMed Central

    Morris, K F; Shannon, R; Lindsey, B G

    2001-01-01

    Long-term facilitation is a respiratory memory expressed as an increase in motor output lasting more than an hour. This change is induced by repeated hypoxia, stimulation of carotid chemoreceptors, or electrical stimulation of the carotid sinus nerve or brainstem mid-line. The present work addressed the hypothesis that persistent changes in medullary respiratory neural networks contribute to long-term facilitation. Carotid chemoreceptors were stimulated by close arterial injection of CO2-saturated saline solution. Phrenic nerve efferent activity and up to 30 single medullary neurones were recorded simultaneously in nucleus tractus solitarii (NTS) including the dorsal respiratory group (DRG), Bötzinger-ventral respiratory group (Böt-VRG), and nucleus raphe obscurus of nine adult cats, anaesthetized, injected with a neuromuscular blocking agent, vagotomized and artificially ventilated. The firing rates of 87 of 105 neurones (83 %) changed following induction of long-term facilitation. Nine of eleven DRG and Böt-VRG putative premotor inspiratory neurones had increased firing rates with long-term facilitation. Fourteen of twenty-one raphe obscurus neurones with control firing rates less than 4 Hz had significant long-term increases in activity. Cross-correlogram analysis suggested that there were changes in effective connectivity of neuron pairs with long-term facilitation. Joint peristimulus time histograms and pattern detection methods used with ‘gravity’ analysis also detected changes in short time scale correlations associated with long-term facilitation. The results suggest that changes in firing rates and synchrony of VRG and DRG premotor neurones and altered effective connectivity among other functionally antecedent elements of the medullary respiratory network contribute to the expression of long-term facilitation. PMID:11306666

  14. Implementation of DRG Payment in France: issues and recent developments.

    PubMed

    Or, Zeynep

    2014-08-01

    In France, a DRG-based payment system was introduced in 2004/2005 for funding acute services in all hospitals with the objectives of improving hospital efficiency, transparency and fairness in payments to public and private hospitals. Despite the initial consensus on the necessity of the reform, providers have become increasingly critical of the system because of the problems encountered during the implementation. In 2012 the government announced its intention to modify the payment model to better deal with its adverse effects. The paper reports on the issues raised by the DRG-based payment in the French hospital sector and provides an overview of the main problems with the French DRG payment model. It also summarises the evidence on its impact and presents recent developments for reforming the current model. DRG-based payment addressed some of the chronic problems inherent in the French hospital market and improved accountability and productivity of health-care facilities. However, it has also created new problems for controlling hospital activity and ensuring that care provided is medically appropriate. In order to alter its adverse effects the French DRG model needs to better align greater efficiency with the objectives of better quality and effectiveness of care. PMID:24962536

  15. Regulation of differentiation flux by Notch signalling influences the number of dopaminergic neurons in the adult brain

    PubMed Central

    Trujillo-Paredes, Niurka; Valencia, Concepción; Guerrero-Flores, Gilda; Arzate, Dulce-María; Baizabal, José-Manuel; Guerra-Crespo, Magdalena; Fuentes-Hernández, Ayari; Zea-Armenta, Iván; Covarrubias, Luis

    2016-01-01

    ABSTRACT Notch signalling is a well-established pathway that regulates neurogenesis. However, little is known about the role of Notch signalling in specific neuronal differentiation. Using Dll1 null mice, we found that Notch signalling has no function in the specification of mesencephalic dopaminergic neural precursor cells (NPCs), but plays an important role in regulating their expansion and differentiation into neurons. Premature neuronal differentiation was observed in mesencephalons of Dll1-deficient mice or after treatment with a Notch signalling inhibitor. Coupling between neurogenesis and dopaminergic differentiation was indicated from the coincident emergence of neuronal and dopaminergic markers. Early in differentiation, decreasing Notch signalling caused a reduction in NPCs and an increase in dopaminergic neurons in association with dynamic changes in the proportion of sequentially-linked dopaminergic NPCs (Msx1/2+, Ngn2+, Nurr1+). These effects in differentiation caused a significant reduction in the number of dopaminergic neurons produced. Accordingly, Dll1 haploinsufficient adult mice, in comparison with their wild-type littermates, have a consistent reduction in neuronal density that was particularly evident in the substantia nigra pars compacta. Our results are in agreement with a mathematical model based on a Dll1-mediated regulatory feedback loop between early progenitors and their dividing precursors that controls the emergence and number of dopaminergic neurons. PMID:26912775

  16. New Hippocampal Neurons Are Not Obligatory for Memory Formation; Cyclin D2 Knockout Mice with No Adult Brain Neurogenesis Show Learning

    ERIC Educational Resources Information Center

    Jaholkowski, Piotr; Kiryk, Anna; Jedynak, Paulina; Abdallah, Nada M. Ben; Knapska, Ewelina; Kowalczyk, Anna; Piechal, Agnieszka; Blecharz-Klin, Kamilla; Figiel, Izabela; Lioudyno, Victoria; Widy-Tyszkiewicz, Ewa; Wilczynski, Grzegorz M.; Lipp, Hans-Peter; Kaczmarek, Leszek; Filipkowski, Robert K.

    2009-01-01

    The role of adult brain neurogenesis (generating new neurons) in learning and memory appears to be quite firmly established in spite of some criticism and lack of understanding of what the new neurons serve the brain for. Also, the few experiments showing that blocking adult neurogenesis causes learning deficits used irradiation and various drugs…

  17. Regulation by equilibrative nucleoside transporter of adenosine outward currents in adult rat spinal dorsal horn neurons.

    PubMed

    Liu, Tao; Fujita, Tsugumi; Kawasaki, Yasuhiko; Kumamoto, Eiichi

    2004-07-30

    A current response induced by superfusing adenosine was examined in substantia gelatinosa (SG) neurons of adult rat spinal cord slices by using the whole-cell patch-clamp technique. In 78% of the neurons examined, adenosine induced an outward current at -70 mV [18.8 +/- 1.1 pA (n = 98) at 1mM] in a dose-dependent manner (EC(50) = 177 microM). A similar current was induced by A(1) agonist N(6)-cyclopentyladenosine (1 microM), whereas A(1) antagonist 8-cyclopentyl-1,3-dipropylxanthine (1 microM) reversed the adenosine action. The adenosine current reversed its polarity at a potential being close to the equilibrium potential for K(+), and was attenuated by Ba(2+) (100 microM) and 4-aminopyridine (5mM) but not tetraethylammonium (5mM). The adenosine current was enhanced in duration by equilibrative nucleoside-transport (rENT1) inhibitor S-(4-nitrobenzyl)-6-thioinosine (1 microM) and adenosine deaminase (ADA) inhibitor erythro-9-(2-hydroxy-3-nonyl) adenine (1 microM), and slowed in falling phase by adenosine kinase (AK) inhibitor iodotubercidine (1 microM). We conclude that a Ba(2+)- and 4-aminopyridine-sensitive K(+) channel in SG neurons is opened via the activation of A(1) receptors by adenosine whose level is possibly regulated by rENT1, adenosine deaminase and adenosine kinase. Considering that intrathecally-administered adenosine analogues produce antinociception, the regulatory systems of adenosine may serve as targets for antinociceptive drugs. PMID:15275960

  18. Enhancement by citral of glutamatergic spontaneous excitatory transmission in adult rat substantia gelatinosa neurons.

    PubMed

    Zhu, Lan; Fujita, Tsugumi; Jiang, Chang-Yu; Kumamoto, Eiichi

    2016-02-10

    Although citral, which is abundantly present in lemongrass, has various actions including antinociception, how citral affects synaptic transmission has not been examined as yet. Citral activates in heterologous cells transient receptor potential vanilloid-1, ankyrin-1, and melastatin-8 (TRPV1, TRPA1, and TRPM8, respectively) channels, the activation of which in the spinal lamina II [substantia gelatinosa (SG)] increases the spontaneous release of L-glutamate from nerve terminals. It remains to be examined what types of transient receptor potential channel in native neurons are activated by citral. With a focus on transient receptor potential activation, we examined the effect of citral on glutamatergic spontaneous excitatory transmission using the whole-cell patch-clamp technique to SG neurons in adult rat spinal cord slices. Bath-applied citral for 3 min increased the frequency of spontaneous excitatory postsynaptic current in a concentration-dependent manner (half-maximal effective concentration=0.58 mM), with a small increase in its amplitude. The spontaneous excitatory postsynaptic current frequency increase produced by citral was repeated at a time interval of 30 min, albeit this action recovered with a slow time course after washout. The presynaptic effect of citral was inhibited by TRPA1 antagonist HC-030031, but not by voltage-gated Na-channel blocker tetrodotoxin, TRPV1 antagonist capsazepine, and TRPM8 antagonist BCTC. It is concluded that citral increases spontaneous L-glutamate release in SG neurons by activating TRPA1 channels. Considering that the SG plays a pivotal role in modulating nociceptive transmission from the periphery, the citral activity could contribute toward at least a part of the modulation. PMID:26720890

  19. Leptin signaling in GFAP-expressing adult glia cells regulates hypothalamic neuronal circuits and feeding

    PubMed Central

    Kim1, Jae Geun; Suyama, Shigetomo; Koch, Marco; Jin, Sungho; Argente-Arizon, Pilar; Argente, Jesus; Liu, Zhong-Wu; Zimmer, Marcelo R.; Jeong, Jin Kwon; Szigeti-Buck, Klara; Gao, Yuanqing; Garcia-Caceres, Cristina; Yi, Chun-Xia; Salmaso, Natalina; Vaccarino, Flora M.; Chowen, Julie; Diano, Sabrina; Dietrich, Marcelo O; Tschöp, Matthias H.; Horvath, Tamas L.

    2014-01-01

    We have shown that synaptic re-organization of hypothalamic feeding circuits in response to metabolic shifts involves astrocytes, cells that can directly respond to the metabolic hormone, leptin, in vitro. It is not known whether the role of glia cells in hypothalamic synaptic adaptions is active or passive. Here we show that leptin receptors are expressed in hypothalamic astrocytes and that conditional, adult deletion of leptin receptors in astrocytes leads to altered glial morphology, decreased glial coverage and elevated synaptic inputs onto pro-opiomelanocortin (POMC)- and Agouti-related protein (AgRP)-producing neurons. Leptin-induced suppression of feeding was diminished, while rebound feeding after fasting or ghrelin administration was elevated in mice with astrocyte-specific leptin receptor deficiency. These data unmask an active role of glial cells in the initiation of hypothalamic synaptic plasticity and neuroendocrine control of feeding by leptin. PMID:24880214

  20. Adult-specific electrical silencing of pacemaker neurons uncouples the molecular oscillator from circadian outputs

    PubMed Central

    Depetris-Chauvin, Ana; Berni, Jimena; Aranovich, Ezequiel J.; Muraro, Nara I.; Beckwith, Esteban J.; Ceriani, María Fernanda

    2011-01-01

    Summary Background Circadian rhythms regulate physiology and behavior through transcriptional feedback loops of clock genes running within specific pacemaker cells. In Drosophila, molecular oscillations in the small ventral Lateral Neurons (sLNvs) command rhythmic behavior under free-running conditions releasing the neuropeptide PIGMENT DISPERSING FACTOR (PDF) in a circadian fashion. Electrical activity in the sLNvs is also required for behavioral rhythmicity. Yet, how temporal information is transduced into behavior remains unclear. Results Here we developed a new tool for temporal control of gene expression to obtain adult-restricted electrical silencing of the PDF circuit, which led to reversible behavioral arrhythmicity. Remarkably, PER oscillations during the silenced phase remained unaltered, indicating that arrhythmicity is a direct consequence of the silenced activity. Accordingly, circadian axonal remodeling and PDF accumulation were severely affected during the silenced phase. Conclusions Although electrical activity of the sLNvs is not a clock component it coordinates circuit outputs leading to rhythmic behavior. PMID:22018542

  1. Forebrain GABAergic neuron precursors integrate into adult spinal cord and reduce injury-induced neuropathic pain

    PubMed Central

    Bráz, JM; Sharif-Naeini, R; Vogt, D; Kriegstein, A; Alvarez-Buylla, A; Rubenstein, JL; Basbaum, AI

    2012-01-01

    Neuropathic pain is a chronic debilitating disease characterized by mechanical allodynia and spontaneous pain. Because symptoms are often unresponsive to conventional methods of pain treatment, new therapeutic approaches are essential. Here, we describe a strategy that not only ameliorates symptoms of neuropathic pain, but is also potentially disease modifying. We show that transplantation of immature telencephalic GABAergic interneurons from the mouse medial ganglionic eminence (MGE) into the adult mouse spinal cord completely reverses the mechanical hypersensitivity produced by peripheral nerve injury. Underlying this improvement is a remarkable integration of the MGE transplants into the host spinal cord circuitry, in which the transplanted cells make functional connections with both primary afferent and spinal cord neurons. By contrast, MGE transplants were not effective against inflammatory pain. Our findings suggest that MGE-derived GABAergic interneurons overcome the spinal cord hyperexcitability that is a hallmark of nerve-injury induced neuropathic pain. PMID:22632725

  2. TRPA1 Is Functionally Expressed Primarily by IB4-Binding, Non-Peptidergic Mouse and Rat Sensory Neurons

    PubMed Central

    Stucky, Cheryl L.

    2012-01-01

    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 functionally

  3. A Simple, Highly Efficient Method for Heterologous Expression in Mammalian Primary Neurons Using Cationic Lipid-mediated mRNA Transfection

    PubMed Central

    Williams, Damian J.; Puhl, Henry L.; Ikeda, Stephen R.

    2010-01-01

    Expression of heterologous proteins in adult mammalian neurons is a valuable technique for the study of neuronal function. The post-mitotic 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. PMID:21267423

  4. A Simple, Highly Efficient Method for Heterologous Expression in Mammalian Primary Neurons Using Cationic Lipid-mediated mRNA Transfection.

    PubMed

    Williams, Damian J; Puhl, Henry L; Ikeda, Stephen R

    2010-01-01

    Expression of heterologous proteins in adult mammalian neurons is a valuable technique for the study of neuronal function. The post-mitotic 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 Ca(2+) 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 (G(oA) 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. PMID:21267423

  5. Neuronal Organization of the Brain in the Adult Amphioxus (Branchiostoma lanceolatum): A Study With Acetylated Tubulin Immunohistochemistry.

    PubMed

    Castro, Antonio; Becerra, Manuela; Manso, María Jesús; Anadón, Ramón

    2015-10-15

    Amphioxus (Cephalochordata) belongs to the most basal extant chordates, and knowledge of their brain organization appears to be key to deciphering the early stages of evolution of vertebrate brains. Most comprehensive studies of the organization of the central nervous system of adult amphioxus have investigated the spinal cord. Some brain populations have been characterized via neurochemistry and electron microscopy, and the overall cytoarchitecture of the brain was studied by Ekhart et al. (2003; J. Comp. Neurol. 466:319-330) with general staining methods and retrograde transport from the spinal cord. Here, the cytoarchitecture of the brain of adult amphioxus Branchiostoma lanceolatum was reinvestigated by using acetylated tubulin immunohistochemistry, which specifically stains neurons and fibers, in combination with some ancillary methods. This method allowed reproducible staining and mapping of types of neuron, mostly in brain regions caudal to the entrance level of nerve 2, and its comparison with spinal cord populations. The brain populations studied and discussed in detail were the Retzius bipolar cells, lamellate cells, Joseph cells, various types of translumenal cells, somatic motoneurons, Rohde nucleus cells, small ventral multipolar neurons, and Edinger cells. These observations expand our knowledge of the distribution of cell types and provide additional data on the number of cells and the axonal tracts and commissural regions of the adult amphioxus brain. The results of this comprehensive study provide a framework for comparison of complex adult populations with the early brain neuronal populations revealed in developmental studies of the amphioxus. PMID:25846052

  6. Axon reaction in hypoglossal and dorsal motor vagal neurons of adult rat: incorporation of (3H)leucine

    SciTech Connect

    Aldskogius, H.; Barron, K.D.; Regal, R.

    1984-07-01

    Pairs of adult rats received (/sup 3/H)leucine 0.25, 1, and 16 h before killing and zero to 164 days after unilateral cervical vagotomy and hypoglossal neurotomy. Grain counts and morphometric measurements were made on axotomized and uninjured neurons in histoautoradiographs of the medullary nuclei. Axotomized hypoglossal neurons, which largely survive the injury, both enlarged and incorporated increased amounts of tritiated leucine at each labeling interval, 3 through 28 days postoperatively. In the vagal dorsal motor nucleus (DMN), axotomized cells, which frequently die after neurotomy, enlarged slightly through 28 days postoperatively, then atrophied; DMN neurons increased amino acid uptake for a shorter period (days 7 through 14) than hypoglossal neurons. Axotomized DMN neurons did not sustain increased protein synthesis as long as their hypoglossal counterparts and seemed to fail to increase synthesis of structural proteins with long half-lives (16-h labeling interval). The frequently necrobiotic response of axotomized DMN neurons may relate to these phenomena. From these and earlier results, the authors conclude that axon reaction appears to differ fundamentally in peripheral and central neurons. This difference may have significance for research on regeneration in the central nervous system.

  7. Behavioural Effects of Adult Vitamin D Deficiency in BALB/c Mice Are not Associated with Proliferation or Survival of Neurons in the Adult Hippocampus

    PubMed Central

    Groves, Natalie J.; Bradford, DanaKai; Sullivan, Robert K. P.; Conn, Kyna-Anne; Aljelaify, Rasha Fahad; McGrath, John J.; Burne, Thomas H. J.

    2016-01-01

    Epidemiological studies have shown that up to one third of adults have insufficient levels of vitamin D and there is an association between low vitamin D concentrations and adverse brain outcomes, such as depression. Vitamin D has been shown to be involved in processes associated with neurogenesis during development. Therefore, the aim of this study was to test the hypothesis that adult vitamin D (AVD) deficiency in BALB/c mice was associated with (a) adult hippocampal neurogenesis at baseline, b) following 6 weeks of voluntary wheel running and (c) a depressive-like phenotype on the forced swim test (FST), which may be linked to alterations in hippocampal neurogenesis. We assessed proliferation and survival of adult born hippocampal neurons by counting the number of cells positive for Ki67 and doublecortin (DCX), and incorporation of 5-Bromo-2’-Deoxyuridine (BrdU) within newly born mature neurons using immunohistochemistry. There were no significant effects of diet on number of Ki67+, DCX+ or BrdU+ cells in the dentate gyrus. All mice showed significantly increased number of Ki67+ cells and BrdU incorporation, and decreased immobility time in the FST, after voluntary wheel running. A significant correlation was found in control mice between immobility time in the FST and level of hippocampal neurogenesis, however, no such correlation was found for AVD-deficient mice. We conclude that AVD deficiency was not associated with impaired proliferation or survival of adult born neurons in BALB/c mice and that the impact on rodent behaviour may not be due to altered neurogenesis per se, but to altered function of new hippocampal neurons or processes independent of adult neurogenesis. PMID:27043014

  8. Mirror Neurons System Engagement in Late Adolescents and Adults While Viewing Emotional Gestures

    PubMed Central

    Salvia, Emilie; Süß, Moritz; Tivadar, Ruxandra; Harkness, Sarah; Grosbras, Marie-Hélène

    2016-01-01

    Observing others’ actions enhances muscle-specific cortico-spinal excitability, reflecting putative mirror neurons activity. The exposure to emotional stimuli also modulates cortico-spinal excitability. We investigated how those two phenomena might interact when they are combined, i.e., while observing a gesture performed with an emotion, and whether they change during the transition between adolescence and adulthood, a period of social and brain maturation. We delivered single-pulse transcranial magnetic stimulation (TMS) over the hand area of the left primary motor cortex of 27 healthy adults and adolescents and recorded their right first dorsal interossus (FDI) muscle activity (i.e., motor evoked potential – MEP), while they viewed either videos of neutral or angry hand actions and facial expressions, or neutral objects as a control condition. We reproduced the motor resonance and the emotion effects – hand-actions and emotional stimuli induced greater cortico-spinal excitability than the faces/control condition and neutral videos, respectively. Moreover, the influence of emotion was present for faces but not for hand actions, indicating that the motor resonance and the emotion effects might be non-additive. While motor resonance was observed in both groups, the emotion effect was present only in adults and not in adolescents. We discuss the possible neural bases of these findings. PMID:27489547

  9. Antenatal Glucocorticoid Treatment Induces Adaptations in Adult Midbrain Dopamine Neurons, which Underpin Sexually Dimorphic Behavioral Resilience

    PubMed Central

    Virdee, Kanwar; McArthur, Simon; Brischoux, Frédéric; Caprioli, Daniele; Ungless, Mark A; Robbins, Trevor W; Dalley, Jeffrey W; Gillies, Glenda E

    2014-01-01

    We demonstrated previously that antenatal glucocorticoid treatment (AGT, gestational days 16–19) altered the size and organization of the adult rat midbrain dopaminergic (DA) populations. Here we investigated the consequences of these AGT-induced cytoarchitectural disturbances on indices of DA function in adult rats. We show that in adulthood, enrichment of striatal DA fiber density paralleled AGT-induced increases in the numbers of midbrain DA neurons, which retained normal basal electrophysiological properties. This was co-incident with changes in (i) striatal D2-type receptor levels (increased, both sexes); (ii) D1-type receptor levels (males decreased; females increased); (iii) DA transporter levels (males increased; females decreased) in striatal regions; and (iv) amphetamine-induced mesolimbic DA release (males increased; females decreased). However, despite these profound, sexually dimorphic changes in markers of DA neurotransmission, in-utero glucocorticoid overexposure had a modest or no effect on a range of conditioned and unconditioned appetitive behaviors known to depend on mesolimbic DA activity. These findings provide empirical evidence for enduring AGT-induced adaptive mechanisms within the midbrain DA circuitry, which preserve some, but not all, functions, thereby casting further light on the vulnerability of these systems to environmental perturbations. Furthermore, they demonstrate these effects are achieved by different, often opponent, adaptive mechanisms in males and females, with translational implications for sex biases commonly found in midbrain DA-associated disorders. PMID:23929547

  10. Mirror Neurons System Engagement in Late Adolescents and Adults While Viewing Emotional Gestures.

    PubMed

    Salvia, Emilie; Süß, Moritz; Tivadar, Ruxandra; Harkness, Sarah; Grosbras, Marie-Hélène

    2016-01-01

    Observing others' actions enhances muscle-specific cortico-spinal excitability, reflecting putative mirror neurons activity. The exposure to emotional stimuli also modulates cortico-spinal excitability. We investigated how those two phenomena might interact when they are combined, i.e., while observing a gesture performed with an emotion, and whether they change during the transition between adolescence and adulthood, a period of social and brain maturation. We delivered single-pulse transcranial magnetic stimulation (TMS) over the hand area of the left primary motor cortex of 27 healthy adults and adolescents and recorded their right first dorsal interossus (FDI) muscle activity (i.e., motor evoked potential - MEP), while they viewed either videos of neutral or angry hand actions and facial expressions, or neutral objects as a control condition. We reproduced the motor resonance and the emotion effects - hand-actions and emotional stimuli induced greater cortico-spinal excitability than the faces/control condition and neutral videos, respectively. Moreover, the influence of emotion was present for faces but not for hand actions, indicating that the motor resonance and the emotion effects might be non-additive. While motor resonance was observed in both groups, the emotion effect was present only in adults and not in adolescents. We discuss the possible neural bases of these findings. PMID:27489547

  11. High neuronal/astroglial differentiation plasticity of adult rat hippocampal neural stem/progenitor cells in response to the effects of embryonic and adult cerebrospinal fluids

    PubMed Central

    Peirouvi, T.; Yekani, F.; Azarnia, M.; Massumi, M.

    2015-01-01

    Hippocampal neural stem/progenitor cells (hipp-NS/PCs) of the adult mammalian brain are important sources of neuronal and gial cell production. In this study, the main goal is to investigate the plasticity of these cells in neuronal/astroglial differentiations. To this end, the differentiation of the hipp-NS/PCs isolated from 3-month-old Wistar rats was investigated in response to the embryonic cerebrospinal fluid (E-CSF) including E13.5, E17-CSF and the adult cerebrospinal fluid (A-CSF), all extracted from rats. CSF samples were selected based on their effects on cell behavioral parameters. Primary cell culture was performed in the presence of either normal or high levels of KCL in a culture medium. High levels of KCL cause cell depolarization, and thus the activation of quiescent NSCs. Results from immunocytochemistry (ICC) and semi-quantitative RT-PCR (sRT-PCR) techniques showed that in E-CSF-treated groups, neuronal differentiation increased (E17>E13.5). In contrast, A-CSF decreased and increased neuronal and astroglial differentiations, respectively. Cell survivability and/or proliferation (S/P), evaluated by an MTT assay, increased by E13.5 CSF, but decreased by both E17 CSF and A-CSF. Based on the results, it is finally concluded that adult rat hippocampal proliferative cells are not restricted progenitors but rather show high plasticity in neuronal/astroglial differentiation according to the effects of CSF samples. In addition, using high concentrations of KCL in the primary cell culture led to an increase in the number of NSCs, which in turn resulted in the increase in neuronal or astroglial differentiations after CSF treatment. PMID:27175157

  12. 42 CFR 412.515 - LTC-DRG weighting factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false LTC-DRG weighting factors. 412.515 Section 412.515 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Prospective Payment System for Long-Term Care Hospitals § 412.515...

  13. 42 CFR 412.515 - LTC-DRG weighting factors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 2 2011-10-01 2011-10-01 false LTC-DRG weighting factors. 412.515 Section 412.515 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Prospective Payment System for...

  14. 42 CFR 412.515 - LTC-DRG weighting factors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 2 2013-10-01 2013-10-01 false LTC-DRG weighting factors. 412.515 Section 412.515 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Prospective Payment System for...

  15. 42 CFR 412.515 - LTC-DRG weighting factors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false LTC-DRG weighting factors. 412.515 Section 412.515 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Prospective Payment System for...

  16. 42 CFR 412.515 - LTC-DRG weighting factors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 2 2012-10-01 2012-10-01 false LTC-DRG weighting factors. 412.515 Section 412.515 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Prospective Payment System for...

  17. An old test for new neurons: refining the Morris water maze to study the functional relevance of adult hippocampal neurogenesis

    PubMed Central

    Garthe, Alexander; Kempermann, Gerd

    2013-01-01

    The Morris water maze represents the de-facto standard for testing hippocampal function in laboratory rodents. In the field of adult hippocampal neurogenesis, however, using this paradigm to assess the functional relevance of the new neurons yielded surprisingly inconsistent results. While some authors found aspects of water maze performance to be linked to adult neurogenesis, others obtained different results or could not demonstrate any effect of manipulating adult neurogenesis. In this review we discuss evidence that the large diversity of protocols and setups used is an important aspect in interpreting the differences in the results that have been obtained. Even simple parameters such as pool size, number, and configuration of visual landmarks, or number of trials can become highly relevant for getting the new neurons involved at all. Sets of parameters are often chosen with implicit or explicit concepts in mind and these might lead to different views on the function of adult-generated neurons. We propose that the classical parameters usually used to measure spatial learning performance in the water maze might not be particularly well-suited to sensitively and specifically detect the supposedly highly specific functional changes elicited by the experimental modulation of adult hippocampal neurogenesis. As adult neurogenesis is supposed to affect specific aspects of information processing only in the hippocampus, any claim for a functional relevance of the new neurons has to be based on hippocampus-specific parameters. We also placed a special emphasis on the fact that the dentate gyrus (DG) facilitates the differentiation between contexts as opposed to just differentiating places. In conclusion, while the Morris water maze has proven to be one of the most effective testing paradigms to assess hippocampus-dependent spatial learning, new and more specific questions ask for new parameters. Therefore, the full potential of the water maze task remains to be tapped

  18. 42 CFR 412.10 - Changes in the DRG classification system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 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. 42 CFR 476.84 - Changes as a result of DRG validation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Changes as a result of DRG validation. 476.84... § 476.84 Changes as a result of DRG validation. A provider or practitioner may obtain a review by a QIO... in DRG assignment as a result of QIO validation activities....

  20. 42 CFR 476.84 - Changes as a result of DRG validation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Changes as a result of DRG validation. 476.84... § 476.84 Changes as a result of DRG validation. A provider or practitioner may obtain a review by a QIO... in DRG assignment as a result of QIO validation activities....

  1. When are new hippocampal neurons, born in the adult brain, integrated into the network that processes spatial information?

    PubMed

    Sandoval, C Jimena; Martínez-Claros, Marisela; Bello-Medina, Paola C; Pérez, Oswaldo; Ramírez-Amaya, Víctor

    2011-01-01

    Adult-born neurons in the dentate gyrus (DG) functionally integrate into the behaviorally relevant hippocampal networks, showing a specific Arc-expression response to spatial exploration when mature. However, it is not clear when, during the 4- to 6-week interval that is critical for survival and maturation of these neurons, this specific response develops. Therefore, we characterized Arc expression after spatial exploration or cage control conditions in adult-born neurons from rats that were injected with BrdU on one day and were sacrificed 1, 7, 15, 30, and 45 days post-BrdU injection (PBI). Triple immunostaining for NeuN, Arc, and BrdU was analyzed through the different DG layers. Arc protein expression in BrdU-positive cells was observed from day 1 to day 15 PBI but was not related to behavioral stimulation. The specific Arc-expression response to spatial exploration was observed from day 30 and 45 in about 5% of the BrdU-positive cell population. Most of the BrdU-positive neurons expressing Arc in response to spatial exploration (∼90%) were located in DG layer 1, and no Arc expression was observed in cells located in the subgranular zone (SGZ). Using the current data and that obtained previously, we propose a mathematical model suggesting that new neurons are unlikely to respond to exploration by expressing Arc after they are 301 days old, and also that in a 7-month-old rat the majority (60%) of the neurons that respond to exploration must have been born during adulthood; thus, suggesting that adult neurogenesis in the DG is highly relevant for spatial information processing. PMID:21408012

  2. When Are New Hippocampal Neurons, Born in the Adult Brain, Integrated into the Network That Processes Spatial Information?

    PubMed Central

    Sandoval, C. Jimena; Pérez, Oswaldo; Ramírez-Amaya, Víctor

    2011-01-01

    Adult-born neurons in the dentate gyrus (DG) functionally integrate into the behaviorally relevant hippocampal networks, showing a specific Arc-expression response to spatial exploration when mature. However, it is not clear when, during the 4- to 6-week interval that is critical for survival and maturation of these neurons, this specific response develops. Therefore, we characterized Arc expression after spatial exploration or cage control conditions in adult-born neurons from rats that were injected with BrdU on one day and were sacrificed 1, 7, 15, 30, and 45 days post-BrdU injection (PBI). Triple immunostaining for NeuN, Arc, and BrdU was analyzed through the different DG layers. Arc protein expression in BrdU-positive cells was observed from day 1 to day 15 PBI but was not related to behavioral stimulation. The specific Arc-expression response to spatial exploration was observed from day 30 and 45 in about 5% of the BrdU-positive cell population. Most of the BrdU-positive neurons expressing Arc in response to spatial exploration (∼90%) were located in DG layer 1, and no Arc expression was observed in cells located in the subgranular zone (SGZ). Using the current data and that obtained previously, we propose a mathematical model suggesting that new neurons are unlikely to respond to exploration by expressing Arc after they are 301 days old, and also that in a 7-month-old rat the majority (60%) of the neurons that respond to exploration must have been born during adulthood; thus, suggesting that adult neurogenesis in the DG is highly relevant for spatial information processing. PMID:21408012

  3. Physicians' Patient Load per DRG, the Consumption of Hospital Resources, and the Incentives of the DRG Prospective Payment System.

    ERIC Educational Resources Information Center

    Munoz, Eric; And Others

    1990-01-01

    The relationship between numbers (high or low) of patients per diagnosis-related group (DRG) treated by individual physicians and hospital resource consumption of the patients at a large academic medical center was studied for the period 1985-87. The findings, although a result of many varied factors, suggest a relationship between the two…

  4. Adult ciliary epithelial stem cells generate functional neurons and differentiate into both early and late born retinal neurons under non-cell autonomous influences

    PubMed Central

    2013-01-01

    Background The neural stem cells discovered in the adult ciliary epithelium (CE) in higher vertebrates have emerged as an accessible source of retinal progenitors; these cells can self-renew and possess retinal potential. However, recent studies have cast doubt as to whether these cells could generate functional neurons and differentiate along the retinal lineage. Here, we have systematically examined the pan neural and retinal potential of CE stem cells. Results Molecular and cellular analysis was carried out to examine the plasticity of CE stem cells, obtained from mice expressing green fluorescent protein (GFP) under the influence of the promoter of the rod photoreceptor-specific gene, Nrl, using the neurospheres assay. Differentiation was induced by specific culture conditions and evaluated by both transcripts and protein levels of lineage-specific regulators and markers. Temporal pattern of their levels were examined to determine the expression of genes and proteins underlying the regulatory hierarchy of cells specific differentiation in vitro. Functional attributes of differentiation were examined by the presence of current profiles and pharmacological mobilization of intracellular calcium using whole cell recordings and Fura-based calcium imaging, respectively. We demonstrate that stem cells in adult CE not only have the capacity to generate functional neurons, acquiring the expression of sodium and potassium channels, but also respond to specific cues in culture and preferentially differentiate along the lineages of retinal ganglion cells (RGCs) and rod photoreceptors, the early and late born retinal neurons, respectively. The retinal differentiation of CE stem cells was characterized by the temporal acquisition of the expression of the regulators of RGCs and rod photoreceptors, followed by the display of cell type-specific mature markers and mobilization of intracellular calcium. Conclusions Our study demonstrates the bonafide retinal potential of adult CE

  5. 4–6 week old adult-born hippocampal neurons influence novelty-evoked exploration and contextual fear conditioning

    PubMed Central

    Denny, Christine A.; Burghardt, Nesha S.; Schachter, Daniel M.; Hen, René; Drew, Michael R.

    2011-01-01

    To explore the role of adult hippocampal neurogenesis in novelty processing, we assessed novel object recognition (NOR) in mice after neurogenesis was arrested using focal x-irradiation of the hippocampus, or a reversible, genetic method in which glial fibrillary acidic protein-positive neural progenitor cells are ablated with ganciclovir. Arresting neurogenesis did not alter general activity or object investigation during four exposures with two constant objects. However, when a novel object replaced a constant object, mice with neurogenesis arrested by either ablation method showed increased exploration of the novel object when compared with control mice. The increased novel object exploration did not manifest until 4–6 weeks after x-irradiation or 6 weeks following a genetic ablation, indicating that exploration of the novel object is increased specifically by the elimination of 4–6-week-old adult born neurons. The increased novel object exploration was also observed in older mice, which exhibited a marked reduction in neurogenesis relative to young mice. Mice with neurogenesis arrested by either ablation method were also impaired in 1-trial contextual fear conditioning (CFC) at 6 weeks but not at 4 weeks following ablation, further supporting the idea that 4–6-week old adult born neurons are necessary for specific forms of hippocampal-dependent learning, and suggesting that the NOR and CFC effects have a common underlying mechanism. These data suggest that the transient enhancement of plasticity observed in young adult-born neurons contributes to cognitive functions. PMID:21739523

  6. MicroRNA-210 promotes sensory axon regeneration of adult mice in vivo and in vitro.

    PubMed

    Hu, Yi-Wen; Jiang, Jing-Jing; Yan-Gao; Wang, Rui-Ying; Tu, Guan-Jun

    2016-05-27

    Axon regeneration as a critical step in nerve repairing and remodeling after peripheral nerve injury relies on regulation of gene expression. MicroRNAs are emerging to be important epigenetic regulators of gene expression to control axon regeneration. Here we used a novel in vivo electroporation approach to transfect microRNA-210 (miR-210) or siRNAs to adult mice dorsal root ganglion (DRG) neurons, measured the axon length 3days after sciatic nerve crush or dissociated DRG cultures in vitro to detect the effect of miR-210 in sensory axon regeneration. Importantly, we found that miR-210 overexpression could promote sensory axon regeneration and inhibit apoptsosis by ephrin-A3 (EFNA3). In addition, inhibition of endogenous miR-210 in DRG neurons impaired axon regeneration in vitro and in vivo, the regulatory effect of miR-210 was mediated by increased expression of EFNA3 because downregulation of EFNA3 fully rescued axon regeneration. We thus demonstrate that miR-210 is a new physiological regulator of sensory axon regeneration, and EFNA3 may be the functional target of miR-210. We conclude that miR-210 may play an important role in sensory axon regeneration. PMID:27102143

  7. An improved method for patch clamp recording and calcium imaging of neurons in the intact dorsal root ganglion in rats

    PubMed Central

    Hayar, Abdallah; Gu, Chunping; Al-Chaer, Elie D.

    2008-01-01

    The properties of dorsal root ganglion (DRG) neurons have been mostly investigated in culture of dissociated cells, and it is uncertain whether these cells maintain the electrophysiological properties of the intact DRG neurons. Few attempts have been made to record from DRG neurons in the intact ganglion using the patch clamp technique. In this study, rat DRGs were dissected and incubated for at least 1 hour at 37°C in collagenase (10 mg/ml). We used oblique epi-illumination to visualize DRG neurons and perform patch clamp recordings. All DRG neurons exhibited strong delayed rectifier potassium current and a high threshold for spike generation (−15 mV) that rendered the cells very weakly excitable, generating only one action potential upon strong current injection (>300 pA). It is therefore possible that cultured DRG neurons, commonly used in studies of pain processing, may be hyperexcitable because they acquired "neuropathic" properties due to the injury induced by their dissociation. Electrical stimulation of the attached root produced an antidromic spike in the soma that could be blocked by intracellular hyperpolarization or high frequency stimulation. Imaging intracellular calcium concentration with Oregon Green BAPTA-1 indicates that antidromic stimulation caused a long-lasting increase in intracellular calcium concentration mostly near the cell membrane. This study describes a simple approach to examine the electrophysiological and pharmacological properties and intracellular calcium signaling in DRG neurons in the intact ganglion where the effects of somatic spike invasion can be studied as well. PMID:18588915

  8. Increased Anandamide Uptake by Sensory Neurons Contributes to Hyperalgesia in a Model of Cancer Pain

    PubMed Central

    Khasabova, Iryna A.; Holman, Michelle; Morse, Tim; Burlakova, Natalya; Coicou, Lia; Harding-Rose, Catherine; Simone, Don A.; Seybold, Virginia S.

    2013-01-01

    Opioids do not effectively manage pain in many patients with advanced cancer. Because anandamide (AEA) activation of cannabinoid type-1 receptors (CB1R) on nociceptors reduces nociception, manipulation of AEA metabolism in the periphery may be an effective alternative or adjuvant therapy in the management of cancer pain. AEA is hydrolyzed by the intracellular enzyme fatty acid amide hydrolase (FAAH), and this enzyme activity contributes to uptake of AEA into neurons and to reduction of AEA available to activate CB1R. We used an in vitro preparation of adult murine dorsal root ganglion (DRG) neurons co-cultured with fibrosarcoma cells to investigate how tumors alter the uptake of AEA into neurons. Evidence that the uptake of [3H]AEA into dissociated DRG cells in the co-culture model mimicked the increase in uptake that occurred in DRG cells from tumor-bearing mice supported the utility of the in vitro model to study AEA uptake. Results with the fluorescent AEA analog CAY10455 confirmed that an increase in uptake in the co-culture model occurred in neurons. One factor that contributed to the increase in [3H]AEA uptake was an increase in total cellular cholesterol in the cancer condition. Treatment with the FAAH inhibitor URB597 reduced CAY10455 uptake in the co-culture model to the level observed in DRG neurons maintained in the control condition (i.e., in the absence of fibrosarcoma cells), and this effect was paralleled by OMDM-1, an inhibitor of AEA uptake, at a concentration that had no effect on FAAH activity. Maximally effective concentrations of the two drugs together produced a greater reduction than was observed with each drug alone. Treatment with BMS309403, which competes for AEA binding to fatty acid binding protein-5, mimicked the effect of OMDM-1 in vitro. Local injection of OMDM-1 reduced hyperalgesia in vivo in mice with unilateral tumors in and around the calcaneous bone. Intraplantar injection of OMDM-1 (5 µg) into the tumor-bearing paw reduced

  9. Characterization of thoracic motor and sensory neurons and spinal nerve roots in canine degenerative myelopathy, a potential disease model of amyotrophic lateral sclerosis.

    PubMed

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

    2014-04-01

    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. PMID:24375814

  10. G-Protein Modulation of Voltage-Gated Ca2+ Channels from Isolated Adult Rat Superior Cervical Ganglion Neurons.

    PubMed

    Lu, Van B; Ikeda, Stephen R

    2016-01-01

    Sympathetic neurons isolated from adult rat superior cervical ganglia (SCG) are a well-established model to study G-protein modulation of voltage-gated Ca(2+) channels (VGCCs). SCG neurons can be easily dissociated and are amendable to heterologous expression of genes, including genetic tools to study G-protein signaling pathways, within a time frame to maintain good spatial voltage-clamp control of membrane potential during electrophysiological recordings (8-36 h postdissociation). This protocol focuses on examining G-protein modulation of VGCCs; however, the procedures and experimental setup for acute application of agonists can be applied to study modulation of other ion channels (e.g., M-current, G-protein-coupled inwardly rectifying K(+) channels). We also discuss some common sources of artifacts that can arise during acute drug application onto dissociated neurons, which can mislead interpretation of results. PMID:27140920

  11. Perinatal Exposure to Neuregulin-1 Results in Disinhibition of Adult Midbrain Dopaminergic Neurons: Implication in Schizophrenia Modeling

    PubMed Central

    Namba, Hisaaki; Okubo, Takeshi; Nawa, Hiroyuki

    2016-01-01

    Aberrant neuregulin-1 (NRG1) signals are suggested to associate with the neuropathophysiology of schizophrenia. Employing a mouse schizophrenia model established by neonatal neuregulin-1 challenge, we analysed postpubertal consequence of the NRG1 pretreatment for the electrophysiological property of nigral dopamine neurons. In vivo single unit recordings from anaesthetized NRG1-pretreated mice revealed increased spike bursting of nigral dopamine neurons. In slice preparations from NRG1-pretreated mice, spontaneous firing was elevated relative to controls. The relative increase in firing rates was abolished by a GABAA receptor antagonist. Whole-cell recording showed that perinatal NRG1 pretreatment diminished inhibitory miniature synaptic currents as well as GABAA receptor sensitivity. These results collectively suggest that perinatal exposure to neuregulin-1 results in the disinhibition of nigral dopamine neurons to influence their firing properties at the adult stage when the behavioral deficits are evident. PMID:26935991

  12. The rehabilitation programme of an adult phenylketonuria with upper motor neuron involvement.

    PubMed

    Soyupek, Feray; Koyuncuoglu, Hasan; Cindas, Abdullah; Ilgun, Erdem; Tak, Rukiye

    2009-01-01

    Phenylketonuria (PKU) is a disorder characterized by several biochemical mechanisms which may impair the brain functions in PKU, leading to neurological problems. Our case report concerns a 19 year-old man with phenylketonuria who was evaluated with the onset of stiffness following the abandonment of the phenylalanine-restricted diet. He was assessed with grade-4 spasticity according to Modified Aschworth scale. The deep tendon reflexes had increased and the plantar reflexes were positive. Knee extensions were limited due to the shortening of the hamstring muscles. Serum phenylalanine concentration was elevated and plasma vitamin B12 level was low. Cranial magnetic resonance imaging scan revealed demyelinization area in periventricular deep white matter. We administered a phenylalanine-restricted diet and a rehabilitation program. Following the treatment, spasticity was reduced to grade-1 and patient could walk without aid. This case shows that, the combination of diet, medication and a rehabilitation program is an effective treatment model on adult PKU with upper motor neuron involvement. PMID:20023364

  13. Expression of gangliosides on glial and neuronal cells in normal and pathological adult human brain.

    PubMed

    Marconi, Silvia; De Toni, Luca; Lovato, Laura; Tedeschi, Elisa; Gaetti, Luigi; Acler, Michele; Bonetti, Bruno

    2005-12-30

    Few studies have assessed the glycolipid phenotype of glial cells in the human central nervous system (CNS) in situ. We investigated by immunohistochemistry the expression and cellular distribution of a panel of gangliosides (GM1, GM2, acetyl-GM3, GD1a, GD1b, GD2, GD3, GT1b, GQ1b and the A2B5 antibody) in adult, human normal and pathological brain, namely multiple sclerosis (MS) and other neurological diseases (OND). In normal conditions, we found diffuse expression in the white matter of most gangliosides tested, with the exception of acetyl-GM3, GT1b and GQ1b. By double immunofluorescence with phenotypic markers, GM1 and GD1b were preferentially expressed on GFAP+ astrocytes, GD1a on NG2+ oligodendrocyte precursors, A2B5 immunostained both populations, while GD2 was selectively present on mature oligodendrocytes. In the gray matter, only GM1, GD2 and A2B5 were present on neuronal cells. Interestingly, those gangliosides present on astrocytes in normal conditions were preferentially expressed on NG2+ cells in chronic MS lesions and in OND. Selective expression of GT1b upon astrocytes and NG2+ cells was instead observed in MS lesions, but not in OND. The definition of the glycolipid phenotype of CNS glial cells may be useful to identify distinct biological glial subsets and provide insights on the potential autoantigenic role of gangliosides in CNS autoimmune diseases. PMID:16313974

  14. Cathepsin F mutations cause Type B Kufs disease, an adult-onset neuronal ceroid lipofuscinosis

    PubMed Central

    Smith, Katherine R.; Dahl, Hans-Henrik M.; Canafoglia, Laura; Andermann, Eva; Damiano, John; Morbin, Michela; Bruni, Amalia C.; Giaccone, Giorgio; Cossette, Patrick; Saftig, Paul; Grötzinger, Joachim; Schwake, Michael; Andermann, Frederick; Staropoli, John F.; Sims, Katherine B.; Mole, Sara E.; Franceschetti, Silvana; Alexander, Noreen A.; Cooper, Jonathan D.; Chapman, Harold A.; Carpenter, Stirling; Berkovic, Samuel F.; Bahlo, Melanie

    2013-01-01

    Kufs disease, an adult-onset neuronal ceroid lipofuscinosis, is challenging to diagnose and genetically heterogeneous. Mutations in CLN6 were recently identified in recessive Kufs disease presenting as progressive myoclonus epilepsy (Type A), whereas the molecular basis of cases presenting with dementia and motor features (Type B) is unknown. We performed genome-wide linkage mapping of two families with recessive Type B Kufs disease and identified a single region on chromosome 11 to which both families showed linkage. Exome sequencing of five samples from the two families identified homozygous and compound heterozygous missense mutations in CTSF within this linkage region. We subsequently sequenced CTSF in 22 unrelated individuals with suspected recessive Kufs disease, and identified an additional patient with compound heterozygous mutations. CTSF encodes cathepsin F, a lysosomal cysteine protease, dysfunction of which is a highly plausible candidate mechanism for a storage disorder like ceroid lipofuscinosis. In silico modeling suggested the missense mutations would alter protein structure and function. Moreover, re-examination of a previously published mouse knockout of Ctsf shows that it recapitulates the light and electron-microscopic pathological features of Kufs disease. Although CTSF mutations account for a minority of cases of type B Kufs, CTSF screening should be considered in cases with early-onset dementia and may avoid the need for invasive biopsies. PMID:23297359

  15. The functional expression of mu opioid receptors on sensory neurons is developmentally regulated; morphine analgesia is less selective in the neonate.

    PubMed

    Nandi, Reema; Beacham, Daniel; Middleton, Jacqueta; Koltzenburg, Martin; Howard, Richard F; Fitzgerald, Maria

    2004-09-01

    Opioid requirements in neonatal patients are reported to be lower than older infants and this may be a reflection of the developmental regulation of opioid receptors. In this study we have investigated the postnatal regulation of Mu opioid receptor (MOR) function in both rat lumbar dorsal root ganglion (DRG) cultures and behavioural mechanical and thermal reflex tests in rat pups. Immunostaining with MOR and selective neurofilament (NF200) antibodies was combined with calcium imaging of MOR function in cultured neonatal and adult rat dorsal root ganglion cells. Calcium imaging showed that a significantly greater number of neonatal DRG neurons expressed functional MOR compared to adult (56.5+/-3.4 versus 39.9+/-1.5%, n=8, mean+/-SEM, P<0.001). This expression is confined to the large, neurofilament positive sensory neurons, while expression in small, nociceptive, neurofilament negative neurons remains unchanged. Sensory threshold testing in rat pups showed that the analgesic potency of systemic morphine to mechanical stimulation is significantly greater in the neonate and declines with postnatal age. Morphine analgesic potency in thermal nociceptive tests did not change with postnatal age. These experiments show that the MOR expressed on large DRG neurons in neonates are functional and are subject to postnatal developmental regulation. This changing functional receptor profile is consistent with greater morphine potency in mechanical, but not thermal, sensory tests in young animals. These results have important clinical implications for the use of morphine in neonates and provide a possible explanation for the differences in morphine requirements observed in the youngest patients. PMID:15327807

  16. Colonic Hypersensitivity and Sensitization of Voltage-gated Sodium Channels in Primary Sensory Neurons in Rats with Diabetes

    PubMed Central

    Hu, Ji; Song, Zhen-Yuan; Zhang, Hong-Hong; Qin, Xin; Hu, Shufen; Jiang, Xinghong; Xu, Guang-Yin

    2016-01-01

    Background/Aims Patients with long-standing diabetes often demonstrate intestinal dysfunction and abdominal pain. However, the pathophysiology of abdominal pain in diabetic patients remains elusive. The purpose of study was to determine roles of voltage-gated sodium channels in dorsal root ganglion (DRG) in colonic hypersensitivity of rats with diabetes. Methods Diabetic models were induced by a single intraperitoneal injection of streptozotocin (STZ; 65 mg/kg) in adult female rats, while the control rats received citrate buffer only. Behavioral responses to colorectal distention were used to determine colonic sensitivity in rats. Colon projection DRG neurons labeled with DiI were acutely dissociated for measuring excitability and sodium channel currents by whole-cell patch clamp recordings. Western blot analysis was employed to measure the expression of NaV1.7 and NaV1.8 of colon DRGs. Results STZ injection produced a significantly lower distention threshold than control rats in responding to colorectal distention. STZ injection also depolarized the resting membrane potentials, hyperpolarized action potential threshold, decreased rheobase and increased frequency of action potentials evoked by 2 and 3 times rheobase and ramp current stimulation. Furthermore, STZ injection enhanced neuronal sodium current densities of DRG neurons innervating the colon. STZ injection also led to a significant upregulation of NaV1.7 and NaV1.8 expression in colon DRGs compared with age and sex-matched control rats. Conclusions Our results suggest that enhanced neuronal excitability following STZ injection, which may be mediated by upregulation of NaV1.7 and NaV1.8 expression in DRGs, may play an important role in colonic hypersensitivity in rats with diabetes. PMID:26459453

  17. Hyaluronan and Fibrin Biomaterial as Scaffolds for Neuronal Differentiation of Adult Stem Cells Derived from Adipose Tissue and Skin

    PubMed Central

    Gardin, Chiara; Vindigni, Vincenzo; Bressan, Eriberto; Ferroni, Letizia; Nalesso, Elisa; Puppa, Alessandro Della; D’Avella, Domenico; Lops, Diego; Pinton, Paolo; Zavan, Barbara

    2011-01-01

    Recently, we have described a simple protocol to obtain an enriched culture of adult stem cells organized in neurospheres from two post-natal tissues: skin and adipose tissue. Due to their possible application in neuronal tissue regeneration, here we tested two kinds of scaffold well known in tissue engineering application: hyaluronan based membranes and fibrin-glue meshes. Neurospheres from skin and adipose tissue were seeded onto two scaffold types: hyaluronan based membrane and fibrin-glue meshes. Neurospheres were then induced to acquire a glial and neuronal-like phenotype. Gene expression, morphological feature and chromosomal imbalance (kariotype) were analyzed and compared. Adipose and skin derived neurospheres are able to grow well and to differentiate into glial/neuron cells without any chromosomal imbalance in both scaffolds. Adult cells are able to express typical cell surface markers such as S100; GFAP; nestin; βIII tubulin; CNPase. In summary, we have demonstrated that neurospheres isolated from skin and adipose tissues are able to differentiate in glial/neuron-like cells, without any chromosomal imbalance in two scaffold types, useful for tissue engineering application: hyaluronan based membrane and fibrin-glue meshes. PMID:22072917

  18. Dendritic and Axonal Architecture of Individual Pyramidal Neurons across Layers of Adult Human Neocortex

    PubMed Central

    Mohan, Hemanth; Verhoog, Matthijs B.; Doreswamy, Keerthi K.; Eyal, Guy; Aardse, Romy; Lodder, Brendan N.; Goriounova, Natalia A.; Asamoah, Boateng; B. Brakspear, A.B. Clementine; Groot, Colin; van der Sluis, Sophie; Testa-Silva, Guilherme; Obermayer, Joshua; Boudewijns, Zimbo S.R.M.; Narayanan, Rajeevan T.; Baayen, Johannes C.; Segev, Idan; Mansvelder, Huibert D.; de Kock, Christiaan P.J.

    2015-01-01

    The size and shape of dendrites and axons are strong determinants of neuronal information processing. Our knowledge on neuronal structure and function is primarily based on brains of laboratory animals. Whether it translates to human is not known since quantitative data on “full” human neuronal morphologies are lacking. Here, we obtained human brain tissue during resection surgery and reconstructed basal and apical dendrites and axons of individual neurons across all cortical layers in temporal cortex (Brodmann area 21). Importantly, morphologies did not correlate to etiology, disease severity, or disease duration. Next, we show that human L(ayer) 2 and L3 pyramidal neurons have 3-fold larger dendritic length and increased branch complexity with longer segments compared with temporal cortex neurons from macaque and mouse. Unsupervised cluster analysis classified 88% of human L2 and L3 neurons into human-specific clusters distinct from mouse and macaque neurons. Computational modeling of passive electrical properties to assess the functional impact of large dendrites indicates stronger signal attenuation of electrical inputs compared with mouse. We thus provide a quantitative analysis of “full” human neuron morphologies and present direct evidence that human neurons are not “scaled-up” versions of rodent or macaque neurons, but have unique structural and functional properties. PMID:26318661

  19. Nuclear factor of activated T cells (NFATc4) is required for BDNF-dependent survival of adult-born neurons and spatial memory formation in the hippocampus.

    PubMed

    Quadrato, Giorgia; Benevento, Marco; Alber, Stefanie; Jacob, Carolin; Floriddia, Elisa M; Nguyen, Tuan; Elnaggar, Mohamed Y; Pedroarena, Christine M; Molkentin, Jeffrey D; Di Giovanni, Simone

    2012-06-01

    New neurons generated in the adult dentate gyrus are constantly integrated into the hippocampal circuitry and activated during encoding and recall of new memories. Despite identification of extracellular signals that regulate survival and integration of adult-born neurons such as neurotrophins and neurotransmitters, the nature of the intracellular modulators required to transduce those signals remains elusive. Here, we provide evidence of the expression and transcriptional activity of nuclear factor of activated T cell c4 (NFATc4) in hippocampal progenitor cells. We show that NFATc4 calcineurin-dependent activity is required selectively for survival of adult-born neurons in response to BDNF signaling. Indeed, cyclosporin A injection and stereotaxic delivery of the BDNF scavenger TrkB-Fc in the mouse dentate gyrus reduce the survival of hippocampal adult-born neurons in wild-type but not in NFATc4(-/-) mice and do not affect the net rate of neural precursor proliferation and their fate commitment. Furthermore, associated with the reduced survival of adult-born neurons, the absence of NFATc4 leads to selective defects in LTP and in the encoding of hippocampal-dependent spatial memories. Thus, our data demonstrate that NFATc4 is essential in the regulation of adult hippocampal neurogenesis and identify NFATc4 as a central player of BDNF-driven prosurvival signaling in hippocampal adult-born neurons. PMID:22586092

  20. Growth Cone Biomechanics in Peripheral and Central Nervous System Neurons

    NASA Astrophysics Data System (ADS)

    Urbach, Jeffrey; Koch, Daniel; Rosoff, Will; Geller, Herbert

    2012-02-01

    The growth cone, a highly motile structure at the tip of an axon, integrates information about the local environment and modulates outgrowth and guidance, but little is known about effects of external mechanical cues and internal mechanical forces on growth-cone mediated guidance. We have investigated neurite outgrowth, traction forces and cytoskeletal substrate coupling on soft elastic substrates for dorsal root ganglion (DRG) neurons (from the peripheral nervous system) and hippocampal neurons (from the central) to see how the mechanics of the microenvironment affect different populations. We find that the biomechanics of DRG neurons are dramatically different from hippocampal, with DRG neurons displaying relatively large, steady traction forces and maximal outgrowth and forces on substrates of intermediate stiffness, while hippocampal neurons display weak, intermittent forces and limited dependence of outgrowth and forces on substrate stiffness. DRG growth cones have slower rates of retrograde actin flow and higher density of localized paxillin (a protein associated with substrate adhesion complexes) compared to hippocampal neurons, suggesting that the difference in force generation is due to stronger adhesions and therefore stronger substrate coupling in DRG growth cones.

  1. [Length of hospital stay due to DRG reimbursement].

    PubMed

    Bartkowski, Rolf

    2012-01-01

    The introduction of DRG systems causes a paradigm shift in consideration of length of hospital stay. A daily rate for a hospital bed is an inventive to lengthen hospital stay as long as possible. In a DRG system it would be lucrative to release a patient from hospital as soon as possible and tenable. If DRGs are calculated properly, based on a valid statistical analysis of average length of stay, hospital reimbursement will be ensured in the average of one year. Not cost-effective cases will be compensated with profitable patients. There is no economic need to release or transfer patients from hospital earlier than necessary or tenable. To have sufficient control over the economic situation in each individual patient it is necessary and recommended to build up a cost unit accounting. PMID:22198932

  2. [Nuclear and cytoplasmic RNA in visual cortex neurons of adult rats following visual deprivation and photic stimulation].

    PubMed

    Malinauskaite, L D

    1980-10-01

    It has been shown by two-wavelength cytospectrophotometry of gallocyanin-chrome alum-stained sections that visual deprivation in adult rats kept in a complete darkness for 30 days resulted in an accumulation of cytoplasmic RNA by layer V neurons of the visual cerebral cortex and by the cells of the perineuronal neuroglia of this layer. The nuclear RNA content remained unchanged. Stimulation of intact rats with a flickering or constant light induced an increase in the cytoplasmic RNA in these neurons rather than in the nuclear RNA as well as in RNA in their glial satellite cells. Similar light stimulation of the deprived animals gave rise to a complete return of the neuronal RNA to normal with only a slight decrease in the deprivation-induced RNA accumulation by the neuroglial cells. Neither visual deprivation nor light stimulation affected the RNA content in the neurons and neuroglia of layer V of the motor cerebral cortex. Compartmentation of RNA metabolism within the neuronal-neuroglial unit is discussed. PMID:6159015

  3. Mutations in DNAJC5, Encoding Cysteine-String Protein Alpha, Cause Autosomal-Dominant Adult-Onset Neuronal Ceroid Lipofuscinosis

    PubMed Central

    Nosková, Lenka; Stránecký, Viktor; Hartmannová, Hana; Přistoupilová, Anna; Barešová, Veronika; Ivánek, Robert; Hůlková, Helena; Jahnová, Helena; van der Zee, Julie; Staropoli, John F.; Sims, Katherine B.; Tyynelä, Jaana; Van Broeckhoven, Christine; Nijssen, Peter C.G.; Mole, Sara E.; Elleder, Milan; Kmoch, Stanislav

    2011-01-01

    Autosomal-dominant adult-onset neuronal ceroid lipofuscinosis (ANCL) is characterized by accumulation of autofluorescent storage material in neural tissues and neurodegeneration and has an age of onset in the third decade of life or later. The genetic and molecular basis of the disease has remained unknown for many years. We carried out linkage mapping, gene-expression analysis, exome sequencing, and candidate-gene sequencing in affected individuals from 20 families and/or individuals with simplex cases; we identified in five individuals one of two disease-causing mutations, c.346_348delCTC and c.344T>G, in DNAJC5 encoding cysteine-string protein alpha (CSPα). These mutations—causing a deletion, p.Leu116del, and an amino acid exchange, p.Leu115Arg, respectively—are located within the cysteine-string domain of the protein and affect both palmitoylation-dependent sorting and the amount of CSPα in neuronal cells. The resulting depletion of functional CSPα might cause in parallel the presynaptic dysfunction and the progressive neurodegeneration observed in affected individuals and lysosomal accumulation of misfolded and proteolysis-resistant proteins in the form of characteristic ceroid deposits in neurons. Our work represents an important step in the genetic dissection of a genetically heterogeneous group of ANCLs. It also confirms a neuroprotective role for CSPα in humans and demonstrates the need for detailed investigation of CSPα in the neuronal ceroid lipofuscinoses and other neurodegenerative diseases presenting with neuronal protein aggregation. PMID:21820099

  4. Selective vulnerability of dorsal root ganglia neurons in experimental rabies after peripheral inoculation of CVS-11 in adult mice.

    PubMed

    Rossiter, John P; Hsu, Lena; Jackson, Alan C

    2009-08-01

    The involvement of dorsal root ganglia was studied in an in vivo model of experimental rabies virus infection using the challenge virus standard (CVS-11) strain. Dorsal root ganglia neurons infected with CVS in vitro show prolonged survival and few morphological changes, and are commonly used to study the infection. It has been established that after peripheral inoculation of mice with CVS the brain and spinal cord show relatively few neurodegenerative changes, but detailed studies of pathological changes in dorsal root ganglia have not previously been performed in this in vivo experimental model. In this study, adult ICR mice were inoculated in the right hindlimb footpad with CVS. Spinal cords and dorsal root ganglia were evaluated at serial time points for histopathological and ultrastructural changes and for biochemical markers of cell death. Light microscopy showed multifocal mononuclear inflammatory cell infiltrates in the sensory ganglia and a spectrum of degenerative neuronal changes. Ultrastructural changes in gangliocytes included features characteristic of the axotomy response, the appearance of numerous autophagic compartments, and aggregation of intermediate filaments, while the neurons retained relatively intact mitochondria and plasma membranes. Later in the process, there were more extensive degenerative neuronal changes without typical features of either apoptosis or necrosis. The degree of degenerative neuronal changes in gangliocytes contrasts with observations in CNS neurons in experimental rabies. Hence, gangliocytes exhibit selective vulnerability in this animal model. This contrasts markedly with the fact that they are, unlike CNS neurons, highly permissive to CVS infection in vitro. Further study is needed to determine mechanisms for this selective vulnerability, which will give us a better understanding of the pathogenesis of rabies. PMID:19252919

  5. Expression profile of vesicular nucleotide transporter (VNUT, SLC17A9) in subpopulations of rat dorsal root ganglion neurons.

    PubMed

    Nishida, Kentaro; Nomura, Yuka; Kawamori, Kanako; Moriyama, Yoshinori; Nagasawa, Kazuki

    2014-09-01

    ATP plays an important role in the signal transduction between sensory neurons and satellite cells in dorsal root ganglia (DRGs). In primary cultured DRG neurons, ATP is known to be stored in lysosomes via a vesicular nucleotide transporter (VNUT), and to be released into the intercellular space through exocytosis. DRGs consist of large-, medium- and small-sized neurons, which play different roles in sensory transmission, but there is no information on the expression profiles of VNUT in DRG subpopulations. Here, we obtained detailed expression profiles of VNUT in isolated rat DRG tissues. On immunohistochemical analysis, VNUT was found in DRG neurons, and was predominantly expressed by the small- and medium-sized DRG ones, as judged upon visual inspection, and this was compatible with the finding that the number of VNUT-positive DRG neurons in IB4-positive cells was greater than that in NF200-positive ones. These results suggest that VNUT play a role in ATP accumulation in DRG neurons, especially in small- and medium-sized ones, and might be involved in ATP-mediated nociceptive signaling in DRGs. PMID:25043192

  6. FPGA platform for MEMS Disc Resonance Gyroscope (DRG) control

    NASA Astrophysics Data System (ADS)

    Keymeulen, Didier; Peay, Chris; Foor, David; Trung, Tran; Bakhshi, Alireza; Withington, Phil; Yee, Karl; Terrile, Rich

    2008-04-01

    Inertial navigation systems based upon optical gyroscopes tend to be expensive, large, power consumptive, and are not long lived. Micro-Electromechanical Systems (MEMS) based gyros do not have these shortcomings; however, until recently, the performance of MEMS based gyros had been below navigation grade. Boeing and JPL have been cooperating since 1997 to develop high performance MEMS gyroscopes for miniature, low power space Inertial Reference Unit applications. The efforts resulted in demonstration of a Post Resonator Gyroscope (PRG). This experience led to the more compact Disc Resonator Gyroscope (DRG) for further reduced size and power with potentially increased performance. Currently, the mass, volume and power of the DRG are dominated by the size of the electronics. This paper will detail the FPGA based digital electronics architecture and its implementation for the DRG which will allow reduction of size and power and will increase performance through a reduction in electronics noise. Using the digital control based on FPGA, we can program and modify in real-time the control loop to adapt to the specificity of each particular gyro and the change of the mechanical characteristic of the gyro during its life time.

  7. [G-DRG version 2007: a short overview].

    PubMed

    Müller, Marcel L; Forschner, Andrea; Luger, Thomas A; Rompel, Rainer; Roeder, Norbert; Hensen, Peter

    2007-09-01

    Just as in the year before, the structure and regulations of the new GDRG version 2007 was successfully agreed on a mutual basis by the national self-governing bodies in the German health care system. Although some problems in high-specialized medicine or day clinic care will remain, the current developments demonstrate once more the learning aptitude of the G-DRG-system. Some beneficial and major changes have been made in 2007, but most of them do not touch dermatology. Additional procedure-based payments have been introduced in 2007 including the parenteral administration of such expensive agents as etanercept and itraconazole. A statistical analysis of cost weights of the year 2006 versus 2007 for two university clinics suggests that in dermatology, the increasing complexity of the G-DRG system partly leads to lower cost weights. Overall in 2007 a remarkable increase of complexity and differentiation throughout the DRG-system can be identified as well as a careful expansion of procedure-based payments. PMID:17760899

  8. Differential expression of id genes and their potential regulator znf238 in zebrafish adult neural progenitor cells and neurons suggests distinct functions in adult neurogenesis.

    PubMed

    Diotel, Nicolas; Beil, Tanja; Strähle, Uwe; Rastegar, Sepand

    2015-01-01

    Teleost fish display a remarkable ability to generate new neurons and to repair brain lesions during adulthood. They are, therefore, a very popular model to investigate the molecular mechanisms of constitutive and induced neurogenesis in adult vertebrates. In this study, we investigated the expression patterns of inhibitor of DNA binding (id) genes and of their potential transcriptional repressor, znf238, in the whole brain of adult zebrafish. We show that while id1 is exclusively expressed in ventricular cells in the whole brain, id2a, id3 and id4 genes are expressed in broader areas. Interestingly, znf238 was also detected in these regions, its expression overlapping with id2a, id3 and id4 expression. Further detailed characterization of the id-expressing cells demonstrated that (a) id1 is expressed in type 1 and type 2 neural progenitors as previously published, (b) id2a in type 1, 2 and 3 neural progenitors, (c) id3 in type 3 neural progenitors and (d) id4 in postmitotic neurons. Our data provide a detailed map of id and znf238 expression in the brain of adult zebrafish, supplying a framework for studies of id genes function during adult neurogenesis and brain regeneration in the zebrafish. PMID:26107416

  9. Anatomical gradients of adult neurogenesis and activity: young neurons in the ventral dentate gyrus are activated by water maze training

    PubMed Central

    Snyder, Jason S.; Radik, Ruvim; Wojtowicz, J. Martin; Cameron, Heather A.

    2009-01-01

    Hippocampal function varies in a subregion-specific fashion: spatial processing is thought to rely on the dorsal hippocampus, while anxiety-related behavior relies more on the ventral hippocampus. During development, neurogenesis in the dentate gyrus proceeds along ventral to dorsal as well as suprapyramidal to infrapyramidal gradients, but it is unclear whether regional differences in neurogenesis are maintained in adulthood. Moreover, it is unknown whether young neurons in the adult exhibit subregion-specific patterns of activation. We therefore examined the magnitude of neurogenesis and the activation of young and mature granule cells in dentate gyrus subregions in adult rats that learned a spatial water maze task, swam with no platform, or were left untouched. We found that both adult neurogenesis and granule cell activation, as defined by c-fos expression in the granule cell population as a whole, were higher in the dorsal than the ventral dentate gyrus. In contrast, c-fos expression in adult-born granule cells, identified by PSA-NCAM or location in the subgranular zone, occurred at a higher rate in the opposite subregion, the ventral dentate gyrus. Interestingly, c-fos expression in the entire granule cell population was equivalent in water maze-trained rats and swim control rats, but was increased in the young granule cells only in the learning condition. These results provide new evidence that hippocampally-relevant experience activates young and mature neurons in different dentate gyrus subregions and with different experiential specificity, and suggest that adult-born neurons may play a specific role in anxiety-related behavior or other non-spatial aspects of hippocampal function. PMID:19004012

  10. Assessment of TTX-s and TTX-r Action Potential Conduction along Neurites of NGF and GDNF Cultured Porcine DRG Somata

    PubMed Central

    Jonas, Robin; Klusch, Andreas; Schmelz, Martin; Petersen, Marlen; Carr, Richard W.

    2015-01-01

    Nine isoforms of voltage-gated sodium channels (NaV) have been characterized and in excitable tissues they are responsible for the initiation and conduction of action potentials. For primary afferent neurons residing in dorsal root ganglia (DRG), individual neurons may express multiple NaV isoforms extending the neuron’s functional capabilities. Since expression of NaV isoforms can be differentially regulated by neurotrophic factors we have examined the functional consequences of exposure to either nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) on action potential conduction in outgrowing cultured porcine neurites of DRG neurons. Calcium signals were recorded using the exogenous intensity based calcium indicator Fluo-8®, AM. In 94 neurons, calcium signals were conducted along neurites in response to electrical stimulation of the soma. At an image acquisition rate of 25 Hz it was possible to discern calcium transients in response to individual electrical stimuli. The peak amplitude of electrically-evoked calcium signals was limited by the ability of the neuron to follow the stimulus frequency. The stimulus frequency required to evoke a half-maximal calcium response was approximately 3 Hz at room temperature. In 13 of 14 (93%) NGF-responsive neurites, TTX-r NaV isoforms alone were sufficient to support propagated signals. In contrast, calcium signals mediated by TTX-r NaVs were evident in only 4 of 11 (36%) neurites from somata cultured in GDNF. This establishes a basis for assessing action potential signaling using calcium imaging techniques in individual cultured neurites and suggests that, in the pig, afferent nociceptor classes relying on the functional properties of TTX-r NaV isoforms, such as cold-nociceptors, most probably derive from NGF-responsive DRG neurons. PMID:26407014

  11. Periadolescent ethanol exposure reduces adult forebrain ChAT+IR neurons: correlation with behavioral pathology.

    PubMed

    Ehlers, C L; Criado, J R; Wills, D N; Liu, W; Crews, F T

    2011-12-29

    Substance abuse typically begins in adolescence; therefore, the impact of alcohol during this critical time in brain development is of particular importance. Epidemiological data indicate that excessive alcohol consumption is prevalent among adolescents and may have lasting neurobehavioral consequences. Loss of cholinergic input to the forebrain has been demonstrated following fetal alcohol exposure and in adults with Wernicke-Korsakoff syndrome. In the present study, immunohistochemistry for choline acetyltransferase (ChAT) was determined to assess forebrain cholinergic neurons (Ch1-4), and behavioral changes following periadolescent alcohol exposure. Wistar rats were exposed to intermittent ethanol vapor (14 h on/10 h off/day) for 35 days from postnatal day (PD) 22 to PD 57 (average blood alcohol concentration (BAC): 163 mg%). Rats were withdrawn from vapor and assessed for locomotor activity, startle response, conflict behavior in the open field, and immobility in the forced swim test, as adults. Rats were then sacrificed at day 71/72 and perfused for histochemical analyses. Ethanol vapor-exposed rats displayed: increased locomotor activity 8 h after the termination of vapor delivery for that 24 h period at day 10 and day 20 of alcohol vapor exposure, significant reductions in the amplitude of their responses to prepulse stimuli during the startle paradigm at 24 h withdrawal, and at 2 weeks following withdrawal, less anxiety-like and/or more "disinhibitory" behavior in the open field conflict, and more immobility in the forced swim test. Quantitative analyses of ChAT immunoreactivity revealed a significant reduction in cell counts in the Ch1-2 and Ch3-4 regions of the basal forebrain in ethanol vapor-exposed rats. This reduction in cell counts was significantly correlated with less anxiety-like and/or more "disinhibitory" behavior in the open field conflict test. These studies demonstrate that behavioral measures of arousal, affective state, disinhibitory

  12. TGF-beta signalling in the adult neurogenic niche promotes stem cell quiescence as well as generation of new neurons

    PubMed Central

    Kandasamy, Mahesh; Lehner, Bernadette; Kraus, Sabrina; Sander, Paul Ramm; Marschallinger, Julia; Rivera, Francisco J; Trümbach, Dietrich; Ueberham, Uwe; Reitsamer, Herbert A; Strauss, Olaf; Bogdahn, Ulrich; Couillard-Despres, Sebastien; Aigner, Ludwig

    2014-01-01

    Members of the transforming growth factor (TGF)-β family govern a wide range of mechanisms in brain development and in the adult, in particular neuronal/glial differentiation and survival, but also cell cycle regulation and neural stem cell maintenance. This clearly created some discrepancies in the field with some studies favouring neuronal differentiation/survival of progenitors and others favouring cell cycle exit and neural stem cell quiescence/maintenance. Here, we provide a unifying hypothesis claiming that through its regulation of neural progenitor cell (NPC) proliferation, TGF-β signalling might be responsible for (i) maintaining stem cells in a quiescent stage, and (ii) promoting survival of newly generated neurons and their functional differentiation. Therefore, we performed a detailed histological analysis of TGF-β1 signalling in the hippocampal neural stem cell niche of a transgenic mouse that was previously generated to express TGF-β1 under a tetracycline regulatable Ca-Calmodulin kinase promoter. We also analysed NPC proliferation, quiescence, neuronal survival and differentiation in relation to elevated levels of TGF-β1 in vitro and in vivo conditions. Finally, we performed a gene expression profiling to identify the targets of TGF-β1 signalling in adult NPCs. The results demonstrate that TGF-β1 promotes stem cell quiescence on one side, but also neuronal survival on the other side. Thus, considering the elevated levels of TGF-β1 in ageing and neurodegenerative diseases, TGF-β1 signalling presents a molecular target for future interventions in such conditions. PMID:24779367

  13. TGF-beta signalling in the adult neurogenic niche promotes stem cell quiescence as well as generation of new neurons.

    PubMed

    Kandasamy, Mahesh; Lehner, Bernadette; Kraus, Sabrina; Sander, Paul Ramm; Marschallinger, Julia; Rivera, Francisco J; Trümbach, Dietrich; Ueberham, Uwe; Reitsamer, Herbert A; Strauss, Olaf; Bogdahn, Ulrich; Couillard-Despres, Sebastien; Aigner, Ludwig

    2014-07-01

    Members of the transforming growth factor (TGF)-β family govern a wide range of mechanisms in brain development and in the adult, in particular neuronal/glial differentiation and survival, but also cell cycle regulation and neural stem cell maintenance. This clearly created some discrepancies in the field with some studies favouring neuronal differentiation/survival of progenitors and others favouring cell cycle exit and neural stem cell quiescence/maintenance. Here, we provide a unifying hypothesis claiming that through its regulation of neural progenitor cell (NPC) proliferation, TGF-β signalling might be responsible for (i) maintaining stem cells in a quiescent stage, and (ii) promoting survival of newly generated neurons and their functional differentiation. Therefore, we performed a detailed histological analysis of TGF-β1 signalling in the hippocampal neural stem cell niche of a transgenic mouse that was previously generated to express TGF-β1 under a tetracycline regulatable Ca-Calmodulin kinase promoter. We also analysed NPC proliferation, quiescence, neuronal survival and differentiation in relation to elevated levels of TGF-β1 in vitro and in vivo conditions. Finally, we performed a gene expression profiling to identify the targets of TGF-β1 signalling in adult NPCs. The results demonstrate that TGF-β1 promotes stem cell quiescence on one side, but also neuronal survival on the other side. Thus, considering the elevated levels of TGF-β1 in ageing and neurodegenerative diseases, TGF-β1 signalling presents a molecular target for future interventions in such conditions. PMID:24779367

  14. Neural precursors (NPCs) from adult L967Q mice display early commitment to "in vitro" neuronal differentiation and hyperexcitability.

    PubMed

    DiFebo, Francesca; Curti, Daniela; Botti, Francesca; Biella, Gerardo; Bigini, Paolo; Mennini, Tiziana; Toselli, Mauro

    2012-08-01

    The pathogenic factors leading to selective degeneration of motoneurons in ALS are not yet understood. However, altered functionality of voltage-dependent Na(+) channels may play a role since cortical hyperexcitability was described in ALS patients and riluzole, the only drug approved to treat ALS, seems to decrease glutamate release via blockade or inactivation of voltage-dependent Na(+) channels. The wobbler mouse, a murine model of motoneuron degeneration, shares some of the clinical features of human ALS. At early stages of the wobbler disease, increased cortical hyperexcitability was observed. Moreover, riluzole reduced motoneuron loss and muscular atrophy in treated wobbler mice. Here, we focussed our attention on specific electrophysiological properties, like voltage-activated Na(+) currents and underlying regenerative electrical activity, as read-outs of the neuronal maturation process of neural stem/progenitor cells (NPCs) isolated from the subventricular zone (SVZ) of adult early symptomatic wobbler mice. In self-renewal conditions, the rate of wobbler NPC proliferation "in vitro" was 30% lower than that of healthy mice. Conversely, the number of wobbler NPCs displaying early neuronal commitment and action potentials was significantly higher. Upon switching from proliferative to differentiative conditions, NPCs underwent significant changes in the key properties of voltage gated Na(+) currents. The most notable finding, in cells with neuronal morphology, was an increase in Na(+) current density that strictly correlated with an increased probability to generate action potentials. This feature was remarkably more pronounced in neurons differentiated from wobbler NPCs that upon sustained stimulation, displayed short trains of pathological facilitation. In agreement with this result, an increase in the number of c-Fos positive cells, a surrogate marker of neuronal network activation, was observed in the mesial cortex of the wobbler mice "in situ". Thus these

  15. Vitamin D Receptor and Enzyme Expression in Dorsal Root Ganglia of Adult Female Rats: Modulation by Ovarian Hormones

    PubMed Central

    Tague, Sarah E.; Smith, Peter G.

    2010-01-01

    Vitamin D insufficiency impacts sensory processes including pain and proprioception, but little is known regarding vitamin D signaling in adult sensory neurons. We analyzed female rat dorsal root ganglia (DRG) for vitamin receptor (VDR) and the vitamin D metabolizing enzymes CYP27B1 and CYP24. Western blots and immunofluorescence revealed the presence of these proteins in sensory neurons. Nuclear VDR immunoreactivity was present within nearly all neurons, while cytoplasmic VDR was found preferentially in unmyelinated calcitonin gene-related peptide (CGRP)-positive neurons, colocalizing with CYP27B1 and CYP24. These data suggest that 1,25(OH)2D3 may affect sensory neurons through nuclear or extranuclear signaling pathways. In addition, local vitamin D metabolite concentrations in unmyelinated sensory neurons may be controlled through expression of CYP27B1 and CYP24. Because vitamin D deficiency appears to exacerbate some peri-menopausal pain syndromes, we assessed the effect of ovariectomy on vitamin D-related proteins. Two weeks following ovariectomy, total VDR expression in DRG dropped significantly, owing to a slight decrease in the percentage of total neurons expressing nuclear VDR and a large drop in unmyelinated CGRP-positive neurons expressing cytoplasmic VDR. Total CYP27B1 expression dropped significantly, predominantly due to decreased expression within unmyelinated CGRP-positive neurons. CYP24 expression remained unchanged. Therefore, unmyelinated CGRP-positive neurons appear to have a distinct vitamin D phenotype with hormonally-regulated ligand and receptor levels. These findings imply that vitamin D signaling may play a specialized role in a neural cell population that is primarily nociceptive. PMID:20969950

  16. The Effects of Target Skeletal Muscle Cells on Dorsal Root Ganglion Neuronal Outgrowth and Migration In Vitro

    PubMed Central

    Zhang, Weiwei; Li, Zhenzhong

    2013-01-01

    Targets of neuronal innervations play a vital role in regulating the survival and differentiation of innervating neurotrophin-responsive neurons. During development, neurons extend axons to their targets, and then their survival become dependent on the trophic substances secreted by their target cells. Sensory endings were present on myoblasts, myotubes, and myofibers in all intrafusal bundles regardless of age. The interdependence of sensory neurons and skeletal muscle (SKM) cells during both embryonic development and the maintenance of the mature functional state has not been fully understood. In the present study, neuromuscular cocultures of organotypic dorsal root ganglion (DRG) explants and dissociate SKM cells were established. Using this culture system, the morphological relationship between DRG neurons and SKM cells, neurites growth and neuronal migration were investigated. The migrating neurons were determined by fluorescent labeling of microtubule-associated protein-2 (MAP-2) and neurofilament 200 (NF-200) or growth-associated protein 43 (GAP-43). The expression of NF-200 and GAP-43 and their mRNAs was evaluated by Western blot assay and real time-PCR analysis. The results reveal that DRG explants showed more dense neurites outgrowth in neuromuscular cocultures as compared with that in the culture of DRG explants alone. The number of total migrating neurons (the MAP-2-expressing neurons) and the percentage NF-200-immunoreactive (IR) and GAP-43-IR neurons increased significantly in the presence of SKM cells. The levels of NF-200 and GAP-43 and their mRNAs increased significantly in neuromuscular cocultures as compared with that in the culture of DRG explants alone. These results suggested that target SKM cells play an important role in regulating neuronal protein synthesis, promoting neuritis outgrowth and neuronal migration of DRG explants in vitro. These results not only provide new clues for a better understanding of the association of SKM cells with

  17. Characterization of Thoracic Motor and Sensory Neurons and Spinal Nerve Roots in Canine Degenerative Myelopathy, a Potential Disease Model of Amyotrophic Lateral Sclerosis

    PubMed Central

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

    2014-01-01

    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 if 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 (MN) 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, or of their axons. Axonal loss in thoracic sensory roots and sensory nerve death suggest 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. PMID:24375814

  18. Brain slice biotinylation: an ex vivo approach to measure region-specific plasma membrane protein trafficking in adult neurons.

    PubMed

    Gabriel, Luke R; Wu, Sijia; Melikian, Haley E

    2014-01-01

    Regulated endocytic trafficking is the central mechanism facilitating a variety of neuromodulatory events, by dynamically controlling receptor, ion channel, and transporter cell surface presentation on a minutes time scale. There is a broad diversity of mechanisms that control endocytic trafficking of individual proteins. Studies investigating the molecular underpinnings of trafficking have primarily relied upon surface biotinylation to quantitatively measure changes in membrane protein surface expression in response to exogenous stimuli and gene manipulation. However, this approach has been mainly limited to cultured cells, which may not faithfully reflect the physiologically relevant mechanisms at play in adult neurons. Moreover, cultured cell approaches may underestimate region-specific differences in trafficking mechanisms. Here, we describe an approach that extends cell surface biotinylation to the acute brain slice preparation. We demonstrate that this method provides a high-fidelity approach to measure rapid changes in membrane protein surface levels in adult neurons. This approach is likely to have broad utility in the field of neuronal endocytic trafficking. PMID:24747337

  19. All-Trans Retinoic Acid Induces Expression of a Novel Intergenic Long Noncoding RNA in Adult rat Primary Hippocampal Neurons.

    PubMed

    Kour, Sukhleen; Rath, Pramod C

    2016-02-01

    Around 90% of the mammalian genome undergoes pervasive transcription into various types of small and long regulatory noncoding RNAs, whereas only ∼ 1.5% codes for proteins. Long noncoding RNAs (lncRNAs) constitute diverse classes of sense- and antisense transcripts that are abundantly expressed in the mammalian central nervous system (CNS) in cell type- and developmental stage-specific manners. They are implicated in brain development, differentiation, neuronal plasticity, and other cognitive functions. Mammalian brain requires the vitamin A metabolite all-trans retinoic acid (atRA) for its normal development, differentiation, and cell-fate determination. However, its role in adult brain function is less understood. Here, we report atRA-mediated transcriptional upregulation of endogenous expression of a novel long intergenic noncoding RNA-rat brain expressed (LINC-RBE) in cultured primary hippocampal neurons from adult rat. We have previously reported LINC-RBE as an intergenic, simple repeat sequence containing lncRNA highly expressed in the rat brain. This is a first-time report of involvement of atRA in transcriptional upregulation of lncRNA expression in rat hippocampal neurons. Therefore, it may be involved in regulation of brain function and disease. PMID:26572536

  20. Growth and turning properties of adult glial cell-derived neurotrophic factor coreceptor α1 nonpeptidergic sensory neurons.

    PubMed

    Guo, GuiFang; Singh, Vandana; Zochodne, Douglas W

    2014-09-01

    An overlapping population of adult primary sensory neurons that innervate the skin express the glial cell-derived neurotrophic factor coreceptor α1 (GFRα1), the lectin IB4, and the "regenerative brake" phosphatase and tensin homolog deleted on chromosome 10. Using an adapted turning and growth assay, we analyzed the growth cone behavior of adult immunoselected GFRα1 sensory neurons. These neurons had less robust baseline growth and reluctant responsiveness to individual growth factors but responded to synergistic types of input from glial cell-derived neurotrophic factor, hepatocyte growth factor, a phosphatase and tensin homolog deleted on chromosome 10 inhibitor, or a downstream Rho kinase inhibitor. Hepatocyte growth factor and the phosphatase and tensin homolog deleted on chromosome 10 inhibitor were associated with growth cone turning. A gradient of protein extracted from skin samples, a primary target of GFRα1 axons, replicated the impact of synergistic support. Within the skin, glial cell-derived neurotrophic factor was expressed within epidermal axons, indicating an autocrine role accompanying local hepatocyte growth factor synthesis. Taken together, our findings identify unique growth properties and plasticity of a distinct population of epidermal axons that are relevant to neurologic repair and skin reinnervation. PMID:25101700

  1. Lmx1a and Lmx1b regulate mitochondrial functions and survival of adult midbrain dopaminergic neurons.

    PubMed

    Doucet-Beaupré, Hélène; Gilbert, Catherine; Profes, Marcos Schaan; Chabrat, Audrey; Pacelli, Consiglia; Giguère, Nicolas; Rioux, Véronique; Charest, Julien; Deng, Qiaolin; Laguna, Ariadna; Ericson, Johan; Perlmann, Thomas; Ang, Siew-Lan; Cicchetti, Francesca; Parent, Martin; Trudeau, Louis-Eric; Lévesque, Martin

    2016-07-26

    The LIM-homeodomain transcription factors Lmx1a and Lmx1b play critical roles during the development of midbrain dopaminergic progenitors, but their functions in the adult brain remain poorly understood. We show here that sustained expression of Lmx1a and Lmx1b is required for the survival of adult midbrain dopaminergic neurons. Strikingly, inactivation of Lmx1a and Lmx1b recreates cellular features observed in Parkinson's disease. We found that Lmx1a/b control the expression of key genes involved in mitochondrial functions, and their ablation results in impaired respiratory chain activity, increased oxidative stress, and mitochondrial DNA damage. Lmx1a/b deficiency caused axonal pathology characterized by α-synuclein(+) inclusions, followed by a progressive loss of dopaminergic neurons. These results reveal the key role of these transcription factors beyond the early developmental stages and provide mechanistic links between mitochondrial dysfunctions, α-synuclein aggregation, and the survival of dopaminergic neurons. PMID:27407143

  2. 7, 8, 3′-Trihydroxyflavone Promotes Neurite Outgrowth and Protects Against Bupivacaine-Induced Neurotoxicity in Mouse Dorsal Root Ganglion Neurons

    PubMed Central

    Shi, Haohong; Luo, Xingjing

    2016-01-01

    Background 7, 8, 3′-trihydroxyflavone (THF) is a novel pro-neuronal small molecule that acts as a TrkB agonist. In this study, we examined the effect of THF on promoting neuronal growth and protecting anesthetics-induced neurotoxicity in dorsal root ganglion (DRG) neurons in vitro. Material/Methods Neonatal mouse DRG neurons were cultured in vitro and treated with various concentrations of THF. The effect of THF on neuronal growth was investigated by neurite outgrowth assay and Western blot. In addition, the protective effects of THF on bupivacaine-induced neurotoxicity were investigated by apoptosis TUNEL assay, neurite outgrowth assay, and Western blot, respectively. Results THF promoted neurite outgrowth of DRG neurons in dose-dependent manner, with an EC50 concentration of 67.4 nM. Western blot analysis showed THF activated TrkB signaling pathway by inducing TrkB phosphorylation. THF also rescued bupivacaine-induced neurotoxicity by reducing apoptosis and protecting neurite retraction in DRG neurons. Furthermore, the protection of THF in bupivacaine-injured neurotoxicity was directly associated with TrkB phosphorylation in a concentration-dependent manner in DRG neurons. Conclusions THF has pro-neuronal effect on DRG neurons by promoting neurite growth and protecting against bupivacaine-induced neurotoxicity, likely through TrkB activation. PMID:27371503

  3. Notch Is Required in Adult Drosophila Sensory Neurons for Morphological and Functional Plasticity of the Olfactory Circuit

    PubMed Central

    Struhl, Gary

    2015-01-01

    Olfactory receptor neurons (ORNs) convey odor information to the central brain, but like other sensory neurons were thought to play a passive role in memory formation and storage. Here we show that Notch, part of an evolutionarily conserved intercellular signaling pathway, is required in adult Drosophila ORNs for the structural and functional plasticity of olfactory glomeruli that is induced by chronic odor exposure. Specifically, we show that Notch activity in ORNs is necessary for the odor specific increase in the volume of glomeruli that occurs as a consequence of prolonged odor exposure. Calcium imaging experiments indicate that Notch in ORNs is also required for the chronic odor induced changes in the physiology of ORNs and the ensuing changes in the physiological response of their second order projection neurons (PNs). We further show that Notch in ORNs acts by both canonical cleavage-dependent and non-canonical cleavage-independent pathways. The Notch ligand Delta (Dl) in PNs switches the balance between the pathways. These data define a circuit whereby, in conjunction with odor, N activity in the periphery regulates the activity of neurons in the central brain and Dl in the central brain regulates N activity in the periphery. Our work highlights the importance of experience dependent plasticity at the first olfactory synapse. PMID:26011623

  4. Altered dendritic arborization of amygdala neurons in young adult rats orally intubated with Clitorea ternatea aqueous root extract.

    PubMed

    Rai, Kiranmai S; Murthy, K Dilip; Rao, Muddanna S; Karanth, K Sudhakar

    2005-07-01

    Young adult (60 day old) Wistar rats of either sex were orally intubated with 50 mg/kg body weight and 100 mg/kg body weight of aqueous root extract of Clitoria ternatea (CTR) for 30 days, along with age-matched saline controls. These rats were then subjected to passive avoidance tests and the results from these studies showed a significant increase in passive avoidance learning and retention. Subsequent to the passive avoidance tests, these rats were killed by decapitation. The amygdala was processed for Golgi staining and the stained neurons were traced using a camera lucida and analysed. The results showed a significant increase in dendritic intersections, branching points and dendritic processes arising from the soma of amygdaloid neurons in CTR treated rats especially in the 100 mg/kg group of rats, compared with age-matched saline controls. This improved dendritic arborization of amygdaloid neurons correlates with the increased passive avoidance learning and memory in the CTR treated rats as reported earlier. The results suggest that Clitoria ternatea aqueous root extract enhances memory by increasing the functional growth of neurons of the amygdala. PMID:16161034

  5. The role of myosin-II in force generation of DRG filopodia and lamellipodia

    PubMed Central

    Sayyad, Wasim A.; Amin, Ladan; Fabris, Paolo; Ercolini, Erika; Torre, Vincent

    2015-01-01

    Differentiating neurons process the mechanical stimulus by exerting the protrusive forces through lamellipodia and filopodia. We used optical tweezers, video imaging and immunocytochemistry to analyze the role of non-muscle myosin-II on the protrusive force exerted by lamellipodia and filopodia from developing growth cones (GCs) of isolated Dorsal Root Ganglia (DRG) neurons. When the activity of myosin-II was inhibited by 30 μM Blebbistatin protrusion/retraction cycles of lamellipodia slowed down and during retraction lamellipodia could not lift up axially as in control condition. Inhibition of actin polymerization with 25 nM Cytochalasin-D and of microtubule polymerization with 500 nM Nocodazole slowed down the protrusion/retraction cycles, but only Cytochalasin-D decreased lamellipodia axial motion. The force exerted by lamellipodia treated with Blebbistatin decreased by 50%, but, surprisingly, the force exerted by filopodia increased by 20-50%. The concomitant disruption of microtubules caused by Nocodazole abolished the increase of the force exerted by filopodia treated with Blebbistatin. These results suggest that; i- Myosin-II controls the force exerted by lamellipodia and filopodia; ii- contractions of the actomyosin complex formed by filaments of actin and myosin have an active role in ruffle formation; iii- myosin-II is an essential component of the structural stability of GCs architecture. PMID:25598228

  6. Autophagy inhibition in endogenous and nutrient-deprived conditions reduces dorsal root ganglia neuron survival and neurite growth in vitro.

    PubMed

    Clarke, Joseph-Patrick; Mearow, Karen

    2016-07-01

    Peripheral neuropathies can result in cytoskeletal changes in axons, ultimately leading to Wallerian degeneration and cell death. Recently, autophagy has been studied as a potential target for improving axonal survival and growth during peripheral nerve damage. This study investigates the influence of autophagy on adult dorsal root ganglia (DRG) neuron survival and axonal growth under control and nutrient deprivation conditions. Constitutive autophagy was modulated with pharmacological activators (rapamycin; Rapa) and inhibitors (3-methyladenine, bafilomycin A1) in conjunction with either a nutrient-stable environment (standard culture medium) or a nutrient-deprived environment (Hank's balanced salt solution + Ca(2+) /Mg(2+) ). The results demonstrated that autophagy inhibition decreased cell viability and reduced neurite growth and branching complexity. Although autophagy was upregulated with nutrient deprivation compared with the control, it was not further activated by rapamycin, suggesting a threshold level of autophagy. Overall, both cellular and biochemical approaches combined to show the influence of autophagy on adult DRG neuron survival and growth. © 2016 Wiley Periodicals, Inc. PMID:27018986

  7. Visual patch clamp recording of neurons in thick portions of the adult spinal cord.

    PubMed

    Munch, Anders Sonne; Smith, Morten; Moldovan, Mihai; Perrier, Jean-François

    2010-07-15

    The study of visually identified neurons in slice preparations from the central nervous system offers considerable advantages over in vivo preparations including high mechanical stability in the absence of anaesthesia and full control of the extracellular medium. However, because of their relative thinness, slices are not appropriate for investigating how individual neurons integrate synaptic inputs generated by large numbers of neurons. Here we took advantage of the exceptional resistance of the turtle to anoxia to make slices of increasing thicknesses (from 300 to 3000 microm) from the lumbar enlargement of the spinal cord. With a conventional upright microscope in which the light condenser was carefully adjusted, we could visualize neurons present at the surface of the slice and record them with the whole-cell patch clamp technique. We show that neurons present in the middle of the preparation remain alive and capable of generating action potentials. By stimulating the lateral funiculus we can evoke intense synaptic activity associated with large increases in conductance of the recorded neurons. The conductance increases substantially more in neurons recorded in thick slices suggesting that the size of the network recruited with the stimulation increases with the thickness of the slices. We also find that that the number of spontaneous excitatory postsynaptic currents (EPSCs) is higher in thick slices compared with thin slices while the number of spontaneous inhibitory postsynaptic currents (IPSCs) remains constant. These preliminary data suggest that inhibitory and excitatory synaptic connections are balanced locally while excitation dominates long-range connections in the spinal cord. PMID:20488203

  8. Spatio-temporal regulations and functions of neuronal alternative RNA splicing in developing and adult brains.

    PubMed

    Iijima, Takatoshi; Hidaka, Chiharu; Iijima, Yoko

    2016-08-01

    Alternative pre-mRNA splicing is a fundamental mechanism that generates molecular diversity from a single gene. In the central nervous system (CNS), key neural developmental steps are thought to be controlled by alternative splicing decisions, including the molecular diversity underlying synaptic wiring, plasticity, and remodeling. Significant progress has been made in understanding the molecular mechanisms and functions of alternative pre-mRNA splicing in neurons through studies in invertebrate systems; however, recent studies have begun to uncover the potential role of neuronal alternative splicing in the mammalian CNS. This article provides an overview of recent findings regarding the regulation and function of neuronal alternative splicing. In particular, we focus on the spatio-temporal regulation of neurexin, a synaptic adhesion molecule, by neuronal cell type-specific factors and neuronal activity, which are thought to be especially important for characterizing neural development and function within the mammalian CNS. Notably, there is increasing evidence that implicates the dysregulation of neuronal splicing events in several neurological disorders. Therefore, understanding the detailed mechanisms of neuronal alternative splicing in the mammalian CNS may provide plausible treatment strategies for these diseases. PMID:26853282

  9. Gastrin-releasing peptide contributes to the regulation of adult hippocampal neurogenesis and neuronal development.

    PubMed

    Walton, Noah M; de Koning, Anoek; Xie, Xiuyuan; Shin, Rick; Chen, Qian; Miyake, Shinichi; Tajinda, Katsunori; Gross, Adam K; Kogan, Jeffrey H; Heusner, Carrie L; Tamura, Kouichi; Matsumoto, Mitsuyuki

    2014-09-01

    In the postnatal hippocampus, newly generated neurons contribute to learning and memory. Disruptions in neurogenesis and neuronal development have been linked to cognitive impairment and are implicated in a broad variety of neurological and psychiatric disorders. To identify putative factors involved in this process, we examined hippocampal gene expression alterations in mice possessing a heterozygous knockout of the calcium/calmodulin-dependent protein kinase II alpha heterozygous knockout gene (CaMK2α-hKO), an established model of cognitive impairment that also displays altered neurogenesis and neuronal development. Using this approach, we identified gastrin-releasing peptide (GRP) as the most dysregulated gene. In wild-type mice, GRP labels NeuN-positive neurons, the lone exception being GRP-positive, NeuN-negative cells in the subgranular zone, suggesting GRP expression may be relevant to neurogenesis and/or neuronal development. Using a model of in vitro hippocampal neurogenesis, we determined that GRP signaling is essential for the continued survival and development of newborn neurons, both of which are blocked by transient knockdown of GRP's cognate receptor (GRPR). Furthermore, GRP appears to negatively regulate neurogenesis-associated proliferation in neural stem cells both in vitro and in vivo. Intracerebroventricular infusion of GRP resulted in a decrease in immature neuronal markers, increased cAMP response element-binding protein (CREB) phosphorylation, and decreased neurogenesis. Despite increased levels of GRP mRNA, CaMK2α-hKO mutant mice expressed reduced levels of GRP peptide. This lack of GRP may contribute to the elevated neurogenesis and impaired neuronal development, which are reversed following exogenous GRP infusion. Based on these findings, we hypothesize that GRP modulates neurogenesis and neuronal development and may contribute to hippocampus-associated cognitive impairment. PMID:24806094

  10. Ablation of huntingtin in adult neurons is nondeleterious but its depletion in young mice causes acute pancreatitis.

    PubMed

    Wang, Guohao; Liu, Xudong; Gaertig, Marta A; Li, Shihua; Li, Xiao-Jiang

    2016-03-22

    The Huntington's disease (HD) protein, huntingtin (HTT), is essential for early development. Because suppressing the expression of mutantHTTis an important approach to treat the disease, we must first understand the normal function of Htt in adults versus younger animals. Using inducibleHttknockout mice, we found thatHttdepletion does not lead to adult neurodegeneration or animal death at >4 mo of age, which was also verified by selectively depletingHttin neurons. On the other hand, young Htt KO mice die at 2 mo of age of acute pancreatitis due to the degeneration of pancreatic acinar cells. Importantly, Htt interacts with the trypsin inhibitor, serine protease inhibitor Kazal-type 3 (Spink3), to inhibit activation of digestive enzymes in acinar cells in young mice, and transgenicHTTcan rescue the early death of Htt KO mice. These findings point out age- and cell type-dependent vital functions of Htt and the safety of knocking down neuronal Htt expression in adult brains as a treatment. PMID:26951659

  11. Remodeling of Hyperpolarization-Activated Current, Ih, in Ah-Type Visceral Ganglion Neurons Following Ovariectomy in Adult Rats

    PubMed Central

    Xu, Wen-Xiao; Yan, Zhen-Yu; Liu, Yang; Zhou, Jia-Ying; Zhang, Hao-Cheng; Wang, Li-Juan; Pan, Xiao-Dong; Fu, Yili

    2013-01-01

    Hyperpolarization-activated currents (Ih) mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels modulate excitability of myelinated A− and Ah-type visceral ganglion neurons (VGN). Whether alterations in Ih underlie the previously reported reduction of excitability of myelinated Ah-type VGNs following ovariectomy (OVX) has remained unclear. Here we used the intact nodose ganglion preparation in conjunction with electrophysiological approaches to examine the role of Ih remodeling in altering Ah-type neuron excitability following ovariectomy in adult rats. Ah-type neurons were identified based on their afferent conduction velocity. Ah-type neurons in nodose ganglia from non-OVX rats exhibited a voltage ‘sag’ as well as ‘rebound’ action potentials immediately following hyperpolarizing current injections, which both were suppressed by the Ih blocker ZD7288. Repetitive spike activity induced afterhyperpolarizations lasting several hundreds of milliseconds (termed post-excitatory membrane hyperpolarizations, PEMHs), which were significantly reduced by ZD7288, suggesting that they resulted from transient deactivation of Ih during the preceding spike trains. Ovariectomy reduced whole-cell Ih density, caused a hyperpolarizing shift of the voltage-dependence of Ih activation, and slowed Ih activation. OVX-induced Ih remodeling was accompanied by a flattening of the stimulus frequency/response curve and loss of PEMHs. Also, HCN1 mRNA levels were reduced by ∼30% in nodose ganglia from OVX rats compared with their non-OVX counterparts. Acute exposure of nodose ganglia to 17beta-estradiol partly restored Ih density and accelerated Ih activation in Ah-type cells. In conclusion, Ih plays a significant role in modulating the excitability of myelinated Ah-type VGNs in adult female rats. PMID:23951107

  12. Positive, But Not Negative Feedback Actions of Estradiol in Adult Female Mice Require Estrogen Receptor α in Kisspeptin Neurons

    PubMed Central

    Dubois, Sharon L.; Acosta-Martínez, Maricedes; DeJoseph, Mary R.; Wolfe, Andrew; Radovick, Sally; Boehm, Ulrich; Urban, Janice H.

    2015-01-01

    Hypothalamic kisspeptin (Kiss1) neurons express estrogen receptor α (ERα) and exert control over GnRH/LH secretion in female rodents. It has been proposed that estradiol (E2) activation of ERα in kisspeptin neurons in the arcuate nucleus (ARC) suppresses GnRH/LH secretion (negative feedback), whereas E2 activation of ERα in kisspeptin neurons in the anteroventral periventricular nucleus (AVPV) mediates the release of preovulatory GnRH/LH surges (positive feedback). To test these hypotheses, we generated mice bearing kisspeptin cell–specific deletion of ERα (KERαKO) and treated them with E2 regimens that evoke either negative or positive feedback actions on GnRH/LH secretion. Using negative feedback regimens, as expected, E2 effectively suppressed LH levels in ovariectomized (OVX) wild-type (WT) mice to the levels seen in ovary-intact mice. Surprisingly, however, despite the fact that E2 regulation of Kiss1 mRNA expression was abrogated in both the ARC and AVPV of KERαKO mice, E2 also effectively decreased LH levels in OVX KERαKO mice to the levels seen in ovary-intact mice. Conversely, using a positive feedback regimen, E2 stimulated LH surges in WT mice, but had no effect in KERαKO mice. These experiments clearly demonstrate that ERα in kisspeptin neurons is required for the positive, but not negative feedback actions of E2 on GnRH/LH secretion in adult female mice. It remains to be determined whether the failure of KERαKO mice to exhibit GnRH/LH surges reflects the role of ERα in the development of kisspeptin neurons, in the active signaling processes leading to the release of GnRH/LH surges, or both. PMID:25545386

  13. Peripheral nerve injury induces loss of nociceptive neuron-specific Gαi-interacting protein in neuropathic pain rat

    PubMed Central

    Liu, Zhen; Wang, Fei; Fischer, Gregory; Hogan, Quinn H.

    2016-01-01

    Background Gαi-interacting protein (GINIP) is expressed specifically in dorsal root ganglion (DRG) neurons and functions in modulation of peripheral gamma-aminobutyric acid B receptor (GBR). Genetic deletion of GINIP leads to impaired responsiveness to GBR agonist-mediated analgesia in rodent. It is, however, not defined whether nerve injury changes GINIP expression. Results Immunolabeling with validated antibody revealed GINIP expression in ∼40% of total lumbar DRG neurons in normal adult rats. GINIP immunoreactivity was detected in ∼80% of IB4-positive (nonpeptidergic) and ∼30% of CGRP-positive (peptidergic) neurons. GINIP immunoreactivity in the spinal cord dorsal horn was colabeled with IB4 and partially with CGRP. In addition, GINIP was expressed in DRG neurons immunopositive for GBR1, GBR2, Gαi(s), and Gαo and was also extensively colabeled with multiple nociceptive neuronal markers, including Trpv1, NaV1.7, CaV2.2α1b, CaV3.2α1b, TrkA, and Trek2. Peripheral nerve injury by L5 spinal nerve ligation significantly decreased the proportion of GINIP immunoreactivity-positive neurons from 40 ± 8.4% to 0.8 ± 0.1% (p < 0.01, mean ± SD, four weeks after spinal nerve ligation) and the total GINIP protein to 1.3% ± 0.04% of its basal level (p < 0.01, n = 6 animals in each group, two weeks after spinal nerve ligation) in the ipsilateral L5 DRGs. Conclusion Our results show that GINIP is predominantly expressed by small nonpeptidergic nociceptive neurons and that nerve injury triggers loss of GINIP expression. Signal transduction roles of GINIP may be diverse as it colabeled with various subgroups of nociceptive neurons. Future studies may investigate details of the signaling mechanism engaged by GINIP, as well as the pathophysiological significance of lost expression of GINIP in neuropathic pain. PMID:27145804

  14. Memory Loss and Frontal Cognitive Dysfunction in a Patient with Adult-onset Neuronal Intranuclear Inclusion Disease.

    PubMed

    Araki, Kunihiko; Sone, Jun; Fujioka, Yusuke; Masuda, Michihito; Ohdake, Reiko; Tanaka, Yasuhiro; Nakamura, Tomohiko; Watanabe, Hirohisa; Sobue, Gen

    2016-01-01

    Neuronal intranuclear inclusion disease (NIID) is an uncommon progressive neurodegenerative disorder. Adult-onset NIID can result in prominent dementia. We herein describe the case of a 74-year-old man who presented with dementia, cerebellar ataxia, neuropathy, and autonomic dysfunction. Diffusion-weighted imaging showed hyperintensity of the corticomedullary junction. Fluid-attenuated inversion recovery images showed frontal-dominant white matter hyperintensity. NIID was diagnosed from the presence of intranuclear inclusions in a skin biopsy sample. Neuropsychological testing revealed memory loss and frontal cognitive dysfunction, especially in relation to language and executive functions. We were therefore able to confirm the association of NIID with cognitive dysfunction. PMID:27523009

  15. Postnatal dysregulation of Notch signal disrupts dendrite development of adult-born neurons in the hippocampus and contributes to memory impairment

    PubMed Central

    Ding, Xue-Feng; Gao, Xiang; Ding, Xin-Chun; Fan, Ming; Chen, Jinhui

    2016-01-01

    Deficits in the Notch pathway are involved in a number of neurologic diseases associated with mental retardation or/and dementia. The mechanisms by which Notch dysregulation are associated with mental retardation and dementia are poorly understood. We found that Notch1 is highly expressed in the adult-born immature neurons in the hippocampus of mice. Retrovirus mediated knockout of notch1 in single adult-born immature neurons decreases mTOR signaling and compromises their dendrite morphogenesis. In contrast, overexpression of Notch1 intracellular domain (NICD), to constitutively activate Notch signaling in single adult-born immature neurons, promotes mTOR signaling and increases their dendrite arborization. Using a unique genetic approach to conditionally and selectively knockout notch 1 in the postnatally born immature neurons in the hippocampus decreases mTOR signaling, compromises their dendrite morphogenesis, and impairs spatial learning and memory. Conditional overexpression of NICD in the postnatally born immature neurons in the hippocampus increases mTOR signaling and promotes dendrite arborization. These data indicate that Notch signaling plays a critical role in dendrite development of immature neurons in the postnatal brain, and dysregulation of Notch signaling in the postnatally born neurons disrupts their development and thus contributes to the cognitive deficits associated with neurological diseases. PMID:27173138

  16. Postnatal dysregulation of Notch signal disrupts dendrite development of adult-born neurons in the hippocampus and contributes to memory impairment.

    PubMed

    Ding, Xue-Feng; Gao, Xiang; Ding, Xin-Chun; Fan, Ming; Chen, Jinhui

    2016-01-01

    Deficits in the Notch pathway are involved in a number of neurologic diseases associated with mental retardation or/and dementia. The mechanisms by which Notch dysregulation are associated with mental retardation and dementia are poorly understood. We found that Notch1 is highly expressed in the adult-born immature neurons in the hippocampus of mice. Retrovirus mediated knockout of notch1 in single adult-born immature neurons decreases mTOR signaling and compromises their dendrite morphogenesis. In contrast, overexpression of Notch1 intracellular domain (NICD), to constitutively activate Notch signaling in single adult-born immature neurons, promotes mTOR signaling and increases their dendrite arborization. Using a unique genetic approach to conditionally and selectively knockout notch 1 in the postnatally born immature neurons in the hippocampus decreases mTOR signaling, compromises their dendrite morphogenesis, and impairs spatial learning and memory. Conditional overexpression of NICD in the postnatally born immature neurons in the hippocampus increases mTOR signaling and promotes dendrite arborization. These data indicate that Notch signaling plays a critical role in dendrite development of immature neurons in the postnatal brain, and dysregulation of Notch signaling in the postnatally born neurons disrupts their development and thus contributes to the cognitive deficits associated with neurological diseases. PMID:27173138

  17. Adult neuron addition to the zebra finch song motor pathway correlates with the rate and extent of recovery from botox-induced paralysis of the vocal muscles

    PubMed Central

    Pytte, Carolyn; Yu, Yi-Lo; Wildstein, Sara; George, Shanu; Kirn, John

    2011-01-01

    In adult songbirds, neurons are continually incorporated into the telencephalic nucleus HVC, a pre-motor region necessary for the production of learned vocalizations. Previous studies have demonstrated that neuron addition to HVC is highest when song is most variable: in juveniles during song learning, in seasonally singing adults during peaks in plasticity that precede the production of new song components, or during seasonal re-establishment of a previously learned song. These findings suggest that neuron addition provides motor flexibility for the transition from a variable song to a target song. Here we test the association between the quality of song structure and HVC neuron addition by experimentally manipulating syringeal muscle control with botox, which produces a transient partial paralysis. We show that the quality of song structure co-varies with new neuron addition to HVC. Both the magnitude of song distortion and the rate of song recovery following syringeal botox injections were correlated with the number of new neurons incorporated into HVC. We suggest that the quality of song structure is either a cause or consequence of the number of new neurons added to HVC. Birds with naturally high rates of neuron addition may have had the greatest success in recovering song. Alternatively, or in addition, new neuron survival in the song motor pathway may be regulated by the quality of song-generated feedback as song regains its original stereotyped structure. Present results are the first to show a relationship between peripheral muscle control and adult neuron addition to cortical pre-motor circuits. PMID:22114266

  18. The intimate relationship of gonadotropin-releasing hormone neurons with the polysialylated neural cell adhesion molecule revisited across development and adult plasticity.

    PubMed

    Franceschini, Isabelle; Desroziers, Elodie; Caraty, Alain; Duittoz, Anne

    2010-12-01

    The neurohormone gonadotropin-releasing hormone (GnRH) is critical for all the aspects of reproductive life in vertebrates. GnRH is secreted by a small number of neurons dispersed within the preoptic-hypothalamic region. These neurons are derived from the embryonic olfactory pit. They then migrate along olfactory, vomeronasal and terminal nerves to their final destination. Classical approaches to study the regulation of GnRH secretion during the reproductive cycle have focused on the various neuronal inputs on GnRH neurons and their regulation by ovarian steroids. However, it is well known that steroids will change the microenvironment of neuronal networks and can induce plasticity and functional changes. In this review, we will focus on the intimate relationship of developing and adult GnRH neurons with the polysialylated form of neural cell adhesion molecule (PSA-NCAM), a major molecular actor in the morphogenesis and adult plasticity of the nervous system. We will first recapitulate the spatiotemporal relationship between PSA-NCAM and migrating GnRH neurons during embryogenesis of various vertebrate species and discuss its importance for GnRH neuron development as shown by various loss of function studies. In the adult, we will review the relationships between PSA-NCAM and GnRH neurons across various physiological states, and open the discussion to the use of new model systems that can help to unravel the function and mechanism of action of PSA-NCAM on GnRH neuronal network activity and GnRH release. PMID:21143658

  19. Neuron-specific enolase levels in drug-naïve young adults with major depressive disorder.

    PubMed

    Wiener, Carolina David; Molina, Mariane Lopez; Passos, Miguel; Moreira, Fernanda Pedrotti; Bittencourt, Guilherme; de Mattos Souza, Luciano Dias; da Silva, Ricardo Azevedo; Jansen, Karen; Oses, Jean Pierre

    2016-05-01

    The aim of this study is to assess neuron-specific enolase (NSE) levels and clinical features in subjects with major depressive disorder (MDD). This is a cross-sectional study with drug-naïve young adults with MDD (aged 18-29 years). Serum levels of NSE were assessed using the electrochemiluminescence method. MDD diagnosis, suicidal ideation, and time of disease were assessed using the Structured Clinical Interview for DSM-IV (SCID). The Hamilton Depression Rating Scale (HDRS) and Hamilton Anxiety Rating Scale (HARS) were used to assess depressive and anxiety symptoms. No relationship was observed between NSE levels and severity of depressive and anxiety symptoms, time of disease, and suicidal ideation. These results suggest that NSE serum levels were not associated with clinical features of MDD among drug-naïve young adults. PMID:27026487

  20. Kv4 Channels Underlie the Subthreshold-Operating A-type K+-current in Nociceptive Dorsal Root Ganglion Neurons

    PubMed Central

    Phuket, Thanawath Ratanadilok Na; Covarrubias, Manuel

    2009-01-01

    The dorsal root ganglion (DRG) contains heterogeneous populations of sensory neurons including primary nociceptive neurons and C-fibers implicated in pain signaling. Recent studies have demonstrated DRG hyperexcitability associated with downregulation of A-type K+ channels; however, the molecular correlate of the corresponding A-type K+ current (IA) has remained hypothetical. Kv4 channels may underlie the IA in DRG neurons. We combined electrophysiology, molecular biology (Whole-Tissue and Single-Cell RT-PCR) and immunohistochemistry to investigate the molecular basis of the IA in acutely dissociated DRG neurons from 7- to 8-day-old rats. Whole-cell recordings demonstrate a robust tetraethylammonium-resistant (20 mM) and 4-aminopyridine-sensitive (5 mM) IA. Matching Kv4 channel properties, activation and inactivation of this IA occur in the subthreshold range of membrane potentials and the rate of recovery from inactivation is rapid and voltage-dependent. Among Kv4 transcripts, the DRG expresses significant levels of Kv4.1 and Kv4.3 mRNAs. Also, single small-medium diameter DRG neurons (∼30 μm) exhibit correlated frequent expression of mRNAs encoding Kv4.1 and Nav1.8, a known nociceptor marker. In contrast, the expressions of Kv1.4 and Kv4.2 mRNAs at the whole-tissue and single-cell levels are relatively low and infrequent. Kv4 protein expression in nociceptive DRG neurons was confirmed by immunohistochemistry, which demonstrates colocalization of Kv4.3 and Nav1.8, and negligible expression of Kv4.2. Furthermore, specific dominant-negative suppression and overexpression strategies confirmed the contribution of Kv4 channels to IA in DRG neurons. Contrasting the expression patterns of Kv4 channels in the central and peripheral nervous systems, we discuss possible functional roles of these channels in primary sensory neurons. PMID:19668710

  1. Does 5-Bromo-2′-deoxyuridine (BrdU) Disrupt Cell Proliferation and Neuronal Maturation in the Adult Rat Hippocampus In Vivo?

    PubMed Central

    Hancock, Aneeka; Priester, Carolina; Kidder, Emily; Keith, Julian R.

    2014-01-01

    5-Bromo-2′-deoxyuridine (BrdU) is frequently used as a mitotic marker in studies of cell proliferation. Recent studies have reported cytotoxic effects of BrdU on neural progenitor cells in embryonic and neonatal brains in vivo and in adult tissue studied in vitro. The present study was conducted to assess whether BrdU interferes with cell proliferation and neuronal maturation in the rat adult hippocampus in vivo. BrdU effects across a wide range of doses (40 – 480 mg/kg) on cell proliferation and the population of immature neurons in the adult hippocampus were investigated using immunohistochemical labeling methods for the cell cycle marker Ki67 and a marker for immature neurons, doublecortin. BrdU did not influence cell proliferation in the dentate gyrus or the population of immature neurons observed in the adult hippocampus relative to those observed in saline treated controls. Thus, in contrast with reports of deleterious effects of BrdU in embryonic and neonatal tissue and adult tissue studied in vitro, BrdU does not appear to have cytotoxic effects on proliferating hippocampal cells or immature neurons in vivo in rats. PMID:19121338

  2. Does 5-bromo-2'-deoxyuridine (BrdU) disrupt cell proliferation and neuronal maturation in the adult rat hippocampus in vivo?

    PubMed

    Hancock, Aneeka; Priester, Carolina; Kidder, Emily; Keith, Julian R

    2009-05-16

    5-Bromo-2'-deoxyuridine (BrdU) is frequently used as a mitotic marker in studies of cell proliferation. Recent studies have reported cytotoxic effects of BrdU on neural progenitor cells in embryonic and neonatal brains in vivo and in adult tissue studied in vitro. The present study was conducted to assess whether BrdU interferes with cell proliferation and neuronal maturation in the rat adult hippocampus in vivo. BrdU effects across a wide range of doses (40-480 mg/kg) on cell proliferation and the population of immature neurons in the adult hippocampus were investigated using immunohistochemical labeling methods for the cell cycle marker Ki67 and a marker for immature neurons, doublecortin. BrdU did not influence cell proliferation in the dentate gyrus or the population of immature neurons observed in the adult hippocampus relative to those observed in saline treated controls. Thus, in contrast with reports of deleterious effects of BrdU in embryonic and neonatal tissue and adult tissue studied in vitro, BrdU does not appear to have cytotoxic effects on proliferating hippocampal cells or immature neurons in vivo in rats. PMID:19121338

  3. Altered Hippocampal Neurogenesis and Amygdalar Neuronal Activity in Adult Mice with Repeated Experience of Aggression

    PubMed Central

    Smagin, Dmitry A.; Park, June-Hee; Michurina, Tatyana V.; Peunova, Natalia; Glass, Zachary; Sayed, Kasim; Bondar, Natalya P.; Kovalenko, Irina N.; Kudryavtseva, Natalia N.; Enikolopov, Grigori

    2015-01-01

    Repeated experience of winning in a social conflict setting elevates levels of aggression and may lead to violent behavioral patterns. Here, we use a paradigm of repeated aggression and fighting deprivation to examine changes in behavior, neurogenesis, and neuronal activity in mice with positive fighting experience. We show that for males, repeated positive fighting experience induces persistent demonstration of aggression and stereotypic behaviors in daily agonistic interactions, enhances aggressive motivation, and elevates levels of anxiety. When winning males are deprived of opportunities to engage in further fights, they demonstrate increased levels of aggressiveness. Positive fighting experience results in increased levels of progenitor cell proliferation and production of young neurons in the hippocampus. This increase is not diminished after a fighting deprivation period. Furthermore, repeated winning experience decreases the number of activated (c-fos-positive) cells in the basolateral amygdala and increases the number of activated cells in the hippocampus; a subsequent no-fight period restores the number of c-fos-positive cells. Our results indicate that extended positive fighting experience in a social conflict heightens aggression, increases proliferation of neuronal progenitors and production of young neurons in the hippocampus, and decreases neuronal activity in the amygdala; these changes can be modified by depriving the winners of the opportunity for further fights. PMID:26648838

  4. Dendritic morphology of neurons in medial prefrontal cortex, hippocampus, and nucleus accumbens in adult SH rats.

    PubMed

    Sánchez, Fremioth; Gómez-Villalobos, María de Jesús; Juarez, Ismael; Quevedo, Lucía; Flores, Gonzalo

    2011-03-01

    We have studied, in spontaneously hypertensive (SH) rats at different ages (2, 4, and 8 months old), the dendritic morphological changes of the pyramidal neurons of the medial prefrontal cortex (mPFC) and hippocampus and medium spiny neurons of the nucleus accumbens (NAcc) induced by the chronic effect of high-blood pressure. As control animals, we used Wistar-Kioto (WK) rats. Blood pressure was measured every 2 months to confirm the increase in arterial blood pressure. Spontaneous locomotor activity was assessed, and then brains were removed to study the dendritic morphology by the Golgi-Cox stain method followed by Sholl analysis. SH animals at 4 and 8 months of age showed decreased spine density in pyramidal neurons from the mPFC and in medium spiny cells from the NAcc. At 8 months of age as well the pyramidal neurons from the hippocampus exhibited a reduction in the number of dendritic spines. An increase in locomotion in a novel environment at all ages in the SH rats was observed. Our results indicate that high-blood pressure alters the neuronal dendrite morphology of the mPFC, hippocampus, and NAcc. The increased locomotion behavior supports the idea that dopaminergic transmission is altered in the SH rats. This could enhance our understanding of the consequences of chronic high-blood pressure on brain structure, which may implicate cognitive impairment in hypertensive patients. PMID:20665725

  5. Distinct Muscle Biopsy Findings in Genetically Defined Adult-Onset Motor Neuron Disorders

    PubMed Central

    Jokela, Manu; Huovinen, Sanna; Raheem, Olayinka; Lindfors, Mikaela; Palmio, Johanna; Penttilä, Sini; Udd, Bjarne

    2016-01-01

    The objective of this study was to characterize and compare muscle histopathological findings in 3 different genetic motor neuron disorders. We retrospectively re-assessed muscle biopsy findings in 23 patients with autosomal dominant lower motor neuron disease caused by p.G66V mutation in CHCHD10 (SMAJ), 10 X-linked spinal and bulbar muscular atrophy (SBMA) and 11 autosomal dominant c9orf72-mutated amyotrophic lateral sclerosis (c9ALS) patients. Distinct large fiber type grouping consisting of non-atrophic type IIA muscle fibers were 100% specific for the late-onset spinal muscular atrophies (SMAJ and SBMA) and were never observed in c9ALS. Common, but less specific findings included small groups of highly atrophic rounded type IIA fibers in SMAJ/SBMA, whereas in c9ALS, small group atrophies consisting of small-caliber angular fibers involving both fiber types were more characteristic. We also show that in the 2 slowly progressive motor neuron disorders (SMAJ and SBMA) the initial neurogenic features are often confused with considerable secondary “myopathic” changes at later disease stages, such as rimmed vacuoles, myofibrillar aggregates and numerous fibers reactive for fetal myosin heavy chain (dMyHC) antibodies. Based on our findings, muscle biopsy may be valuable in the diagnostic work-up of suspected motor neuron disorders in order to avoid a false ALS diagnosis in patients without clear findings of upper motor neuron lesions. PMID:26999347

  6. Altered Hippocampal Neurogenesis and Amygdalar Neuronal Activity in Adult Mice with Repeated Experience of Aggression.

    PubMed

    Smagin, Dmitry A; Park, June-Hee; Michurina, Tatyana V; Peunova, Natalia; Glass, Zachary; Sayed, Kasim; Bondar, Natalya P; Kovalenko, Irina N; Kudryavtseva, Natalia N; Enikolopov, Grigori

    2015-01-01

    Repeated experience of winning in a social conflict setting elevates levels of aggression and may lead to violent behavioral patterns. Here, we use a paradigm of repeated aggression and fighting deprivation to examine changes in behavior, neurogenesis, and neuronal activity in mice with positive fighting experience. We show that for males, repeated positive fighting experience induces persistent demonstration of aggression and stereotypic behaviors in daily agonistic interactions, enhances aggressive motivation, and elevates levels of anxiety. When winning males are deprived of opportunities to engage in further fights, they demonstrate increased levels of aggressiveness. Positive fighting experience results in increased levels of progenitor cell proliferation and production of young neurons in the hippocampus. This increase is not diminished after a fighting deprivation period. Furthermore, repeated winning experience decreases the number of activated (c-fos-positive) cells in the basolateral amygdala and increases the number of activated cells in the hippocampus; a subsequent no-fight period restores the number of c-fos-positive cells. Our results indicate that extended positive fighting experience in a social conflict heightens aggression, increases proliferation of neuronal progenitors and production of young neurons in the hippocampus, and decreases neuronal activity in the amygdala; these changes can be modified by depriving the winners of the opportunity for further fights. PMID:26648838

  7. Neuronal plasticity in the mushroom body calyx during adult maturation in the honeybee and possible pheromonal influences.

    PubMed

    Muenz, Thomas S; Groh, Claudia; Maisonnasse, Alban; Le Conte, Yves; Plettner, Erika; Rössler, Wolfgang

    2015-12-01

    Honeybee workers express a pronounced age-dependent polyethism switching from various indoor duties to foraging outside the hive. This transition is accompanied by tremendous changes in the sensory environment that sensory systems and higher brain centers have to cope with. Foraging and age have earlier been shown to be associated with volume changes in the mushroom bodies (MBs). Using age- and task-controlled bees this study provides a detailed framework of neuronal maturation processes in the MB calyx during the course of natural behavioral maturation. We show that the MB calyx volume already increases during the first week of adult life. This process is mainly driven by broadening of the Kenyon cell dendritic branching pattern and then followed by pruning of projection neuron axonal boutons during the actual transition from indoor to outdoor duties. To further investigate the flexible regulation of division of labor and its neuronal correlates in a honeybee colony, we studied the modulation of the nurse-forager transition via a chemical communication system, the primer pheromone ethyl oleate (EO). EO is found at high concentrations on foragers in contrast to nurse bees and was shown to delay the onset of foraging. In this study, EO effects on colony behavior were not as robust as expected, and we found no direct correlation between EO treatment and synaptic maturation in the MB calyx. In general, we assume that the primer pheromone EO rather acts in concert with other factors influencing the onset of foraging with its effect being highly adaptive. PMID:25784170

  8. A subset of neurons controls the permeability of the peritrophic matrix and midgut structure in Drosophila adults.

    PubMed

    Kenmoku, Hiroyuki; Ishikawa, Hiroki; Ote, Manabu; Kuraishi, Takayuki; Kurata, Shoichiro

    2016-08-01

    The metazoan gut performs multiple physiological functions, including digestion and absorption of nutrients, and also serves as a physical and chemical barrier against ingested pathogens and abrasive particles. Maintenance of these functions and structures is partly controlled by the nervous system, yet the precise roles and mechanisms of the neural control of gut integrity remain to be clarified in Drosophila Here, we screened for GAL4 enhancer-trap strains and labeled a specific subsets of neurons, using Kir2.1 to inhibit their activity. We identified an NP3253 line that is susceptible to oral infection by Gram-negative bacteria. The subset of neurons driven by the NP3253 line includes some of the enteric neurons innervating the anterior midgut, and these flies have a disorganized proventricular structure with high permeability of the peritrophic matrix and epithelial barrier. The findings of the present study indicate that neural control is crucial for maintaining the barrier function of the gut, and provide a route for genetic dissection of the complex brain-gut axis in adults of the model organism Drosophila. PMID:27229474

  9. “Subpial Fan Cell” — A Class of Calretinin Neuron in Layer 1 of Adult Monkey Prefrontal Cortex

    PubMed Central

    Gabbott, Paul L. A.

    2016-01-01

    Layer 1 of the cortex contains populations of neurochemically distinct neurons and afferent fibers which markedly affect neural activity in the apical dendritic tufts of pyramidal cells. Understanding the causal mechanisms requires knowledge of the cellular architecture and synaptic organization of layer 1. This study has identified eight morphological classes of calretinin immunopositive (CRet+) neurons (including Cajal-Retzius cells) in layer 1 of the prefrontal cortex (PFC) in adult monkey (Macaca fasicularis), with a distinct class — termed “subpial fan (SPF) cell” — described in detail. SPF cells were rare horizontal unipolar CRet+ cells located directly beneath the pia with a single thick primary dendrite that branched into a characteristic fan-like dendritic tree tangential to the pial surface. Dendrites had spines, filamentous processes and thorny branchlets. SPF cells lay millimeters apart with intralaminar axons that ramified widely in upper layer 1. Such cells were GABA immunonegative (-) and occurred in areas beyond PFC. Interspersed amidst SPF cells displaying normal structural integrity were degenerating CRet+ neurons (including SPF cells) and clumps of lipofuscin-rich cellular debris. The number of degenerating SPF cells increased during adulthood. Ultrastructural analyses indicated SPF cell somata received asymmetric (A — presumed excitatory) and symmetric (S — presumed inhibitory) synaptic contacts. Proximal dendritic shafts received mainly S-type and distal shafts mostly A-type input. All dendritic thorns and most dendritic spines received both synapse types. The tangential areal density of SPF cell axonal varicosities varied radially from parent somata — with dense clusters in more distal zones. All boutons formed A-type contacts with CRet- structures. The main post-synaptic targets were dendritic shafts (67%; mostly spine-bearing) and dendritic spines (24%). SPF-SPF cell innervation was not observed. Morphometry of SPF cells

  10. 42 CFR 478.15 - QIO review of changes resulting from DRG validation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false QIO review of changes resulting from DRG validation... review of changes resulting from DRG validation. (a) General rules. (1) A provider or practitioner... validation under section 1866(a)(1)(F) of the Act is entitled to a review of that change if— (i) The...

  11. 42 CFR 478.15 - QIO review of changes resulting from DRG validation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false QIO review of changes resulting from DRG validation... review of changes resulting from DRG validation. (a) General rules. (1) A provider or practitioner... validation under section 1866(a)(1)(F) of the Act is entitled to a review of that change if— (i) The...

  12. Hospital Coding Practice, Data Quality, and DRG-Based Reimbursement under the Thai Universal Coverage Scheme

    ERIC Educational Resources Information Center

    Pongpirul, Krit

    2011-01-01

    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…

  13. Differentiation patterns of mouse embryonic stem cells and induced pluripotent stem cells into neurons.

    PubMed

    Nakamura, Mai; Kamishibahara, Yu; Kitazawa, Ayako; Kawaguchi, Hideo; Shimizu, Norio

    2016-05-01

    Mouse embryonic stem (ES) cells and induced pluripotent stem (iPS) cells have the ability to differentiate in vitro into various cell lineages including neurons. The differentiation of these cells into neurons has potential applications in regenerative medicine. Previously, we reported that a chick dorsal root ganglion (DRG)-conditioned medium (CM) promoted the differentiation of mouse ES and iPS cells into neurons. Here, we used real-time PCR to investigate the differentiation patterns of ES and iPS cells into neurons when DRG-CM was added. DRG-CM promoted the expression levels of βIII-tubulin gene (a marker of postmitotic neurons) in ES and iPS cells. ES cells differentiated into neurons faster than iPS cells, and the maximum peaks of gene expression involved in motor, sensory, and dopaminergic neurons were different. Rho kinase (ROCK) inhibitors could be very valuable at numerous stages in the production and use of stem cells in basic research and eventual cell-based therapies. Thus, we investigated whether the addition of a ROCK inhibitor Y-27632 and DRG-CM on the basis of the differentiation patterns promotes the neuronal differentiation of ES cells. When the ROCK inhibitor was added to the culture medium at the initial stages of cultivation, it stimulated the neuronal differentiation of ES cells more strongly than that stimulated by DRG-CM. Moreover, the combination of the ROCK inhibitor and DRG-CM promoted the neuronal differentiation of ES cells when the ROCK inhibitor was added to the culture medium at day 3. The ROCK inhibitor may be useful for promoting neuronal differentiation of ES cells. PMID:25354731

  14. The hippocampus of the eastern rock sengi: cytoarchitecture, markers of neuronal function, principal cell numbers, and adult neurogenesis.

    PubMed

    Slomianka, Lutz; Drenth, Tanja; Cavegn, Nicole; Menges, Dominik; Lazic, Stanley E; Phalanndwa, Mashudu; Chimimba, Christian T; Amrein, Irmgard

    2013-01-01

    The brains of sengis (elephant shrews, order Macroscelidae) have long been known to contain a hippocampus that in terms of allometric progression indices is larger than that of most primates and equal in size to that of humans. In this report, we provide descriptions of hippocampal cytoarchitecture in the eastern rock sengi (Elephantulus myurus), of the distributions of hippocampal calretinin, calbindin, parvalbumin, and somatostatin, of principal neuron numbers, and of cell numbers related to proliferation and neuronal differentiation in adult hippocampal neurogenesis. Sengi hippocampal cytoarchitecture is an amalgamation of characters that are found in CA1 of, e.g., guinea pig and rabbits and in CA3 and dentate gyrus of primates. Correspondence analysis of total cell numbers and quantitative relations between principal cell populations relate this sengi to macaque monkeys and domestic pigs, and distinguish the sengi from distinct patterns of relations found in humans, dogs, and murine rodents. Calretinin and calbindin are present in some cell populations that also express these proteins in other species, e.g., interneurons at the stratum oriens/alveus border or temporal hilar mossy cells, but neurons expressing these markers are often scarce or absent in other layers. The distributions of parvalbumin and somatostatin resemble those in other species. Normalized numbers of PCNA+ proliferating cells and doublecortin-positive (DCX+) differentiating cells of neuronal lineage fall within the overall ranges of murid rodents, but differed from three murid species captured in the same habitat in that fewer DCX+ cells relative to PCNA+ were observed. The large and well-differentiated sengi hippocampus is not accompanied by correspondingly sized cortical and subcortical limbic areas that are the main hippocampal sources of afferents and targets of efferents. This points to intrinsic hippocampal information processing as the selective advantage of the large sengi hippocampus

  15. The hippocampus of the eastern rock sengi: cytoarchitecture, markers of neuronal function, principal cell numbers, and adult neurogenesis

    PubMed Central

    Slomianka, Lutz; Drenth, Tanja; Cavegn, Nicole; Menges, Dominik; Lazic, Stanley E.; Phalanndwa, Mashudu; Chimimba, Christian T.; Amrein, Irmgard

    2013-01-01

    The brains of sengis (elephant shrews, order Macroscelidae) have long been known to contain a hippocampus that in terms of allometric progression indices is larger than that of most primates and equal in size to that of humans. In this report, we provide descriptions of hippocampal cytoarchitecture in the eastern rock sengi (Elephantulus myurus), of the distributions of hippocampal calretinin, calbindin, parvalbumin, and somatostatin, of principal neuron numbers, and of cell numbers related to proliferation and neuronal differentiation in adult hippocampal neurogenesis. Sengi hippocampal cytoarchitecture is an amalgamation of characters that are found in CA1 of, e.g., guinea pig and rabbits and in CA3 and dentate gyrus of primates. Correspondence analysis of total cell numbers and quantitative relations between principal cell populations relate this sengi to macaque monkeys and domestic pigs, and distinguish the sengi from distinct patterns of relations found in humans, dogs, and murine rodents. Calretinin and calbindin are present in some cell populations that also express these proteins in other species, e.g., interneurons at the stratum oriens/alveus border or temporal hilar mossy cells, but neurons expressing these markers are often scarce or absent in other layers. The distributions of parvalbumin and somatostatin resemble those in other species. Normalized numbers of PCNA+ proliferating cells and doublecortin-positive (DCX+) differentiating cells of neuronal lineage fall within the overall ranges of murid rodents, but differed from three murid species captured in the same habitat in that fewer DCX+ cells relative to PCNA+ were observed. The large and well-differentiated sengi hippocampus is not accompanied by correspondingly sized cortical and subcortical limbic areas that are the main hippocampal sources of afferents and targets of efferents. This points to intrinsic hippocampal information processing as the selective advantage of the large sengi hippocampus

  16. Sexual dimorphism in neuronal number of the posterodorsal medial amygdala is independent of circulating androgens and regional volume in adult rats.

    PubMed

    Morris, John A; Jordan, Cynthia L; Breedlove, S Marc

    2008-02-10

    The posterodorsal medial amygdala (MePD) in rodents integrates olfactory and pheromonal information, which, coupled with the appropriate hormonal signals, may facilitate or repress reproductive behavior in adulthood. MePD volume and neuronal soma size are greater in male rats than in females, and these sexual dimorphisms are maintained by adult circulating hormone levels. Castration of adult males causes these measures to shrink to the size seen in females 4 weeks later, whereas testosterone treatment of adult females for 4 weeks enlarges these measures to the size of males. We used stereological methods to count the number of cells in the MePD and found that, in addition to the sex difference in regional volume and soma size, males also have more MePD neurons than do females, yet these numbers are unaffected by the presence or absence of androgen in adults of either sex. Males also have more glial cells than do females, but, in contrast to the effects on neuronal number, the number of glial cells is affected by androgen in the right MePD of both sexes and, therefore, may contribute to regional volume changes in adulthood in that hemisphere. Thus, regional volume, neuronal size, and glial numbers vary in the MePD of adult rats in response to circulating androgens, but neuronal number does not. These results suggest that the sex difference in neuronal number in the rat MePD may be "organized" by androgens prior to adulthood, whereas regional volume, neuronal size, and glial numbers can be altered by androgens in adulthood. PMID:18076082

  17. Effects of A Voltage Sensitive Calcium Channel Blocker and A Sodium-Calcium Exchanger Inhibitor on Apoptosis of Motor Neurons in Adult Spinal Cord Slices

    PubMed Central

    Momeni, Hamid Reza; Jarahzadeh, Mahsa

    2012-01-01

    Objective: The apoptosis of motor neurons is a critical phenomenon in spinal cord injuries. Adult spinal cord slices were used to investigate whether voltage sensitive calcium channels and Na+/Ca2+ exchangers play a role in the apoptosis of motor neurons. Materials and Methods: In this experimental research, the thoracic region of the adult mouse spinal cord was sliced using a tissue chopper and the slices were incubated in a culture medium in the presence or absence of N/L type voltage sensitive calcium channels blocker (loperamide, 100 µM) or Na+/Ca2+ exchangers inhibitor(bepridil, 20 µM) for 6 hours. 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium (MTT) staining was used to assess slice viability while morphological features of apoptosis in motor neurons were studied using fluorescent staining. Results: After 6 hours in culture, loperamideand bepridil not only increased slice viability, but also prevented motor neuron apoptosis and significantly increased the percentage of viable motor neurons in the ventral horns of the spinal cord. Conclusion: The results of this study suggest that voltage sensitive calcium channels and Na+/Ca2+ exchanger might be involved in the apoptosis of motor neurons in adult spinal cord slices. PMID:23508879

  18. Neonatal chlorpyrifos exposure induces loss of dopaminergic neurons in young adult rats.

    PubMed

    Zhang, Jie; Dai, Hongmei; Deng, Yuanying; Tian, Jing; Zhang, Chen; Hu, Zhiping; Bing, Guoying; Zhao, Lingling

    2015-10-01

    Increasing epidemiological and toxicological evidence suggests that pesticides and other environmental exposures may be associated with the development of Parkinson's disease (PD). Chlorpyrifos (CPF) is a widely used organophosphorous pesticide with developmental neurotoxicity. Its neurotoxicity, notably on the monoamine system, suggests that exposure of CPF may induce dopaminergic neuronal injury. We investigated whether neonatal exposure to CPF contributes to initiation and progression of dopaminergic neurotoxicity and explored the possible underlying mechanisms. The newborn rats were administrated 5 mg/kg CPF subcutaneously from postnatal day (PND) 11 to PND 14 daily. The effect of CPF on dopaminergic neurons, microglia, astrocyte, nuclear factor-κB (NF-κB) p. 65 and p. 38 mitogen-activated protein kinase (MAPK) signaling pathways was analyzed in the substantia nigra of rats at 12h, 24h, 72 h, 16d and 46 d after exposure. CPF-treated rats exhibited significant reduction of dopaminergic neurons at 16d and 46 d after exposure, and a significant increase in the expression of microglia and astrocytes in the substantia nigra after CPF exposure. Intense activation of NF-κB p. 65 and p. 38 MAPK inflammatory signaling pathways was observed. Our findings indicate that neonatal exposure to CPF may induce long-term dopaminergic neuronal damage in the substantia nigra mediated by the activation of inflammatory response via NF-κB p. 65 and p. 38 MAPK pathways in the nigrostriatal system. PMID:26215101

  19. A mathematical model of adult GnRH neurons in mouse brain and its bifurcation analysis.

    PubMed

    Duan, Wen; Lee, Kiho; Herbison, Allan E; Sneyd, James

    2011-05-01

    GnRH neurons are hypothalamic neurons that secrete gonadotropin-releasing hormone (GnRH) which stimulates the release of gonadotropins, one of the crucial hormones for sexual development, fertility and maturation. A mathematical model was built to help elucidate the mechanisms underlying electrical bursting and synchronous [Ca²(+)] transients in GnRH neurons (Lee et al., 2010). The model predicted that bursting in GnRH neurons (at least of the short-bursting type) requires the existence of a [Ca²(+)]-dependent slow after-hyperpolarisation current (sI(AHP-UCL)), and this predicted current was found experimentally. GnRH behaviour under a wide range of conditions (inhibition of Na(+) channels, IP₃ receptors, [Ca²(+)]-dependent K(+) channels, or Ca²(+) pumps, or in the presence of zero extracellular [Ca²(+)]) is successfully reproduced by the model. In this paper, a simplified version of the previous model, with the same qualitative behaviour, is constructed and studied using timescale separation techniques and bifurcation analysis. PMID:21300070

  20. Adolescent Intermittent Ethanol Exposure Is Associated with Increased Risky Choice and Decreased Dopaminergic and Cholinergic Neuron Markers in Adult Rats

    PubMed Central

    Boutros, Nathalie; Semenova, Svetlana; Liu, Wen; Crews, Fulton T.

    2015-01-01

    Background: Binge drinking is prevalent during adolescence and may have effects on the adult brain and behavior. The present study investigated whether adolescent intermittent ethanol exposure alters adult risky choice and prefrontal dopaminergic and forebrain cholinergic neuronal marker levels in male Wistar rats. Methods: Adolescent (postnatal day 28–53) rats were administered 5g/kg of 25% (vol/vol) ethanol 3 times/d in a 2-days–on/2-days–off exposure pattern. In adulthood, risky choice was assessed in the probability discounting task with descending and ascending series of large reward probabilities and after acute ethanol challenge. Immunohistochemical analyses assessed tyrosine hydroxylase, a marker of dopamine and norepinephrine in the prelimbic and infralimbic cortices, and choline acetyltransferase, a marker of cholinergic neurons, in the basal forebrain. Results: All of the rats preferred the large reward when it was delivered with high probability. When the large reward became unlikely, control rats preferred the smaller, safe reward, whereas adolescent intermittent ethanol-exposed rats continued to prefer the risky alternative. Acute ethanol had no effect on risky choice in either group of rats. Tyrosine hydroxylase (prelimbic cortex only) and choline acetyltransferase immunoreactivity levels were decreased in adolescent intermittent ethanol-exposed rats compared with controls. Risky choice was negatively correlated with choline acetyltransferase, implicating decreased forebrain cholinergic activity in risky choice. Conclusions: The decreases in tyrosine hydroxylase and choline acetyltransferase immunoreactivity suggest that adolescent intermittent ethanol exposure has enduring neural effects that may lead to altered adult behaviors, such as increased risky decision making. In humans, increased risky decision making could lead to maladaptive, potentially harmful consequences. PMID:25612895

  1. Injury-Associated PACAP Expression in Rat Sensory and Motor Neurons Is Induced by Endogenous BDNF

    PubMed Central

    Pettersson, Lina M. E.; Geremia, Nicole M.; Ying, Zhengxin; Verge, Valerie M. K.

    2014-01-01

    Peripheral nerve injury results in dramatic upregulation in pituitary adenylate cyclase activating polypeptide (PACAP) expression in adult rat dorsal root ganglia and spinal motor neurons mirroring that described for the neurotrophin brain derived neurotrophic factor (BDNF). Thus, we posited that injury-associated alterations in BDNF expression regulate the changes in PACAP expression observed in the injured neurons. The role of endogenous BDNF in induction and/or maintenance of PACAP mRNA expression in injured adult rat motor and sensory neurons was examined by intrathecally infusing or intraperitoneally injecting BDNF-specific antibodies or control IgGs immediately at the time of L4-L6 spinal nerve injury, or in a delayed fashion one week later for 3 days followed by analysis of impact on PACAP expression. PACAP mRNA in injured lumbar sensory and motor neurons was detected using in situ hybridization, allowing quantification of relative changes between experimental groups, with ATF-3 immunofluorescence serving to identify the injured subpopulation of motor neurons. Both the incidence and level of PACAP mRNA expression were dramatically reduced in injured sensory and motor neurons in response to immediate intrathecal anti-BDNF treatment. In contrast, neither intraperitoneal injections nor delayed intrathecal infusions of anti-BDNF had any discernible impact on PACAP expression. This impact on PACAP expression in response to BDNF immunoneutralization in DRG was confirmed using qRT-PCR or by using BDNF selective siRNAs to reduce neuronal BDNF expression. Collectively, our findings support that endogenous injury-associated BDNF expression is critically involved in induction, but not maintenance, of injury-associated PACAP expression in sensory and motor neurons. PMID:24968020

  2. Neuronal regeneration: Electric and magnetic effects

    SciTech Connect

    Sisken, B.F.; Mullins, R.; McLeod, B. Montana State Univ., Bozeman )

    1991-03-11

    Cultures of dorsal root ganglia (DRG) exposed to direct current (DC) and pulsed electromagnetic fields (PEMF) were compared to controls and DRG treated with NGF. The authors objectives were to determine: (1) the effects of all paradigms on neurite growth and (2) whether there is a correlation between the electric field, or the magnetic field using the field geometry in the dish to differentiate between them. Neurite outgrowth scores were obtained on DRG growing in the inner ring and in the outer ring of 50 mm dishes. Significantly higher scores were correlated with: DRG growing in the vicinity of the cathode in the DC group, and DRG growing at the higher current density levels in the PEMF group. For PEMF, this implies that the effect is electric field rather than magnetic field mediated, or, that the magnetic component affects the sensitivity of the cells to the electric fields. These apparent differences in sensitivity of the neurons to the current density in the different exposure groups may be related to the different frequency contents of the two signals. Corollary experiments performed in the presence of cytosine arabinoside resulted in increased sprouting, but eliminated the differential growth in both DC and PEMF groups.

  3. 42 CFR 476.85 - Conclusive effect of QIO initial denial determinations and changes as a result of DRG validations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... determinations and changes as a result of DRG validations. 476.85 Section 476.85 Public Health CENTERS FOR... denial determinations and changes as a result of DRG validations. A QIO initial denial determination or change as a result of DRG validation is final and binding unless, in accordance with the procedures...

  4. 42 CFR 476.93 - Opportunity to discuss proposed initial denial determination and changes as a result of a DRG...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... determination and changes as a result of a DRG validation. 476.93 Section 476.93 Public Health CENTERS FOR... initial denial determination and changes as a result of a DRG validation. Before a QIO reaches an initial denial determination or makes a change as a result of a DRG validation, it must— (a) Promptly notify...

  5. 42 CFR 476.94 - Notice of QIO initial denial determination and changes as a result of a DRG validation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... changes as a result of a DRG validation. 476.94 Section 476.94 Public Health CENTERS FOR MEDICARE... changes as a result of a DRG validation. (a) Notice of initial denial determination—(1) Parties to be... retrospective review, (excluding DRG validation and post procedure review), within 3 working days of the...

  6. 42 CFR 476.96 - Review period and reopening of initial denial determinations and changes as a result of DRG...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... determinations and changes as a result of DRG validations. 476.96 Section 476.96 Public Health CENTERS FOR... initial denial determinations and changes as a result of DRG validations. (a) General timeframe. A QIO or... initial denial determination or a change as a result of a DRG validation. (b) Extended timeframes. (1)...

  7. 42 CFR 476.93 - Opportunity to discuss proposed initial denial determination and changes as a result of a DRG...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... determination and changes as a result of a DRG validation. 476.93 Section 476.93 Public Health CENTERS FOR... initial denial determination and changes as a result of a DRG validation. Before a QIO reaches an initial denial determination or makes a change as a result of a DRG validation, it must— (a) Promptly notify...

  8. 42 CFR 476.94 - Notice of QIO initial denial determination and changes as a result of a DRG validation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... changes as a result of a DRG validation. 476.94 Section 476.94 Public Health CENTERS FOR MEDICARE... changes as a result of a DRG validation. (a) Notice of initial denial determination—(1) Parties to be... retrospective review, (excluding DRG validation and post procedure review), within 3 working days of the...

  9. 42 CFR 476.96 - Review period and reopening of initial denial determinations and changes as a result of DRG...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... determinations and changes as a result of DRG validations. 476.96 Section 476.96 Public Health CENTERS FOR... initial denial determinations and changes as a result of DRG validations. (a) General timeframe. A QIO or... initial denial determination or a change as a result of a DRG validation. (b) Extended timeframes. (1)...

  10. 42 CFR 476.85 - Conclusive effect of QIO initial denial determinations and changes as a result of DRG validations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... determinations and changes as a result of DRG validations. 476.85 Section 476.85 Public Health CENTERS FOR... denial determinations and changes as a result of DRG validations. A QIO initial denial determination or change as a result of DRG validation is final and binding unless, in accordance with the procedures...

  11. The DRG shift: a new twist for ICD-10 preparation.

    PubMed

    Long, Peri L

    2012-06-01

    Analysis of your specific business is a key component of ICD-10 implementation. An understanding of your organization's current reimbursement trends will go a long way to assessing and preparing for the impact of ICD-10 in your environment. If you cannot be prepared for each detailed scenario, remember that much of the analysis and resolution requires familiar coding, DRG analysis, and claims processing best practices. Now, they simply have the new twist of researching new codes and some new concepts. The news of a delay in the implementation compliance date, along with the release of grouper Version 29, should encourage your educational and business analysis efforts. This is a great opportunity to maintain open communication with the Centers for Medicare & Medicaid Services, Department of Health and Human Services, and Centers for Disease Control. This is also a key time to report any unusual or discrepant findings in order to provide input to the final rule. PMID:22741518

  12. Distinct repriming and closed-state inactivation kinetics of Nav1.6 and Nav1.7 sodium channels in mouse spinal sensory neurons

    PubMed Central

    Herzog, Raimund I; Cummins, Theodore R; Ghassemi, Farshid; Dib-Hajj, Sulayman D; Waxman, Stephen G

    2003-01-01

    While large, myelinated dorsal root ganglion (DRG) neurons are capable of firing at high frequencies, small unmyelinated DRG neurons typically display much lower maximum firing frequencies. However, the molecular basis for this difference has not been delineated. Because the sodium currents in large DRG neurons exhibit rapid repriming (recovery from inactivation) kinetics and the sodium currents in small DRG neurons exhibit predominantly slow repriming kinetics, it has been proposed that differences in sodium channels might contribute to the determination of repetitive firing properties in DRG neurons. A recent study demonstrated that Nav1.7 expression is negatively correlated with conduction velocity and DRG cell size, while the Nav1.6 voltage-gated sodium channel has been implicated as the predominant isoform present at nodes of Ranvier of myelinated fibres. Therefore we characterized and compared the functional properties, including repriming, of recombinant Nav1.6 and Nav1.7 channels expressed in mouse DRG neurons. Both Nav1.6 and Nav1.7 channels generated fast-activating and fast-inactivating currents. However recovery from inactivation was significantly faster (˜5-fold at −70 mV) for Nav1.6 currents than for Nav1.7 currents. The recovery from inactivation of Nav1.6 channels was also much faster than that of native tetrodotoxin-sensitive sodium currents recorded from small spinal sensory neurons, but similar to that of tetrodotoxin-sensitive sodium currents recorded from large spinal sensory neurons. Development of closed-state inactivation was also much faster for Nav1.6 currents than for Nav1.7 currents. Our results indicate that the firing properties of DRG neurons can be tuned by regulating expression of different sodium channel isoforms that have distinct repriming and closed-state inactivation kinetics. PMID:12843211

  13. A role for Runx transcription factor signaling in dorsal root ganglion sensory neuron diversification.

    PubMed

    Kramer, Ina; Sigrist, Markus; de Nooij, Joriene C; Taniuchi, Ichiro; Jessell, Thomas M; Arber, Silvia

    2006-02-01

    Subpopulations of sensory neurons in the dorsal root ganglion (DRG) can be characterized on the basis of sensory modalities that convey distinct peripheral stimuli, but the molecular mechanisms that underlie sensory neuronal diversification remain unclear. Here, we have used genetic manipulations in the mouse embryo to examine how Runx transcription factor signaling controls the acquisition of distinct DRG neuronal subtype identities. Runx3 acts to diversify an Ngn1-independent neuronal cohort by promoting the differentiation of proprioceptive sensory neurons through erosion of TrkB expression in prospective TrkC+ sensory neurons. In contrast, Runx1 controls neuronal diversification within Ngn1-dependent TrkA+ neurons by repression of neuropeptide CGRP expression and controlling the fine pattern of laminar termination in the dorsal spinal cord. Together, our findings suggest that Runx transcription factor signaling plays a key role in sensory neuron diversification. PMID:16446142

  14. Intrathecal administration of rapamycin inhibits the phosphorylation of DRG Nav1.8 and attenuates STZ-induced painful diabetic neuropathy in rats.

    PubMed

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

    2016-04-21

    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. PMID:26946108

  15. Difference in transient ischemia-induced neuronal damage and glucose transporter-1 immunoreactivity in the hippocampus between adult and young gerbils

    PubMed Central

    Park, Seung Min; Lee, Jae-Chul; Chen, Bai Hui; Shin, Bich-Na; Cho, Jeong Hwi; Kim, In Hye; Park, Joon Ha; Won, Moo-Ho; Ahn, Ji Hyeon; Tae, Hyun-Jin; Shin, Myoung Cheol; Park, Chan Woo; Cho, Jun Hwi; Lee, Hui Young

    2016-01-01

    Objective(s): The alteration of glucose transporters is closely related with the pathogenesis of brain edema. We compared neuronal damage/death in the hippocampus between adult and young gerbils following transient cerebral ischemia/reperfusion and changes of glucose transporter-1(GLUT-1)-immunoreactive microvessels in their ischemic hippocampal CA1 region. Materials and Methods: Transient cerebral ischemia was developed by 5-min occlusion of both common carotid arteries. Neuronal damage was examined by cresyl violet staining, NeuN immunohistochemistry and Fluoro-Jade B histofluorescence staining and changes in GLUT-1 expression was carried out by immunohistochemistry. Results: About 90% of pyramidal neurons only in the adult CA1 region were damaged after ischemia/reperfusion; in the young, about 53 % of pyramidal neurons were damaged from 7 days after ischemia/reperfusion. The density of GLUT-1-immunoreactive microvessels was significantly higher in the young sham-group than that in the adult sham-group. In the ischemia-operated-groups, the density of GLUT-1-immunoreactive microvessels was significantly decreased in the adult and young at 1 and 4 days post-ischemia, respectively, thereafter, the density of GLUT-1-immunoreactive microvessels was gradually increased in both groups after ischemia/reperfusion. Conclusion: CA1 pyramidal neurons of the young gerbil were damaged much later than that in the adult and that GLUT-1-immunoreactive microvessels were significantly decreased later in the young. These data indicate that GLUT-1 might differently contribute to neuronal damage according to age after ischemic insults. PMID:27403259

  16. Assessing DRG cost accounting with respect to resource allocation and tariff calculation: the case of Germany

    PubMed Central

    2012-01-01

    The purpose of this paper is to analyze the German diagnosis related groups (G-DRG) cost accounting scheme by assessing its resource allocation at hospital level and its tariff calculation at national level. First, the paper reviews and assesses the three steps in the G-DRG resource allocation scheme at hospital level: (1) the groundwork; (2) cost-center accounting; and (3) patient-level costing. Second, the paper reviews and assesses the three steps in G-DRG national tariff calculation: (1) plausibility checks; (2) inlier calculation; and (3) the “one hospital” approach. The assessment is based on the two main goals of G-DRG introduction: improving transparency and efficiency. A further empirical assessment attests high costing quality. The G-DRG cost accounting scheme shows high system quality in resource allocation at hospital level, with limitations concerning a managerially relevant full cost approach and limitations in terms of advanced activity-based costing at patient-level. However, the scheme has serious flaws in national tariff calculation: inlier calculation is normative, and the “one hospital” model causes cost bias, adjustment and representativeness issues. The G-DRG system was designed for reimbursement calculation, but developed to a standard with strategic management implications, generalized by the idea of adapting a hospital’s cost structures to DRG revenues. This combination causes problems in actual hospital financing, although resource allocation is advanced at hospital level. PMID:22935314

  17. Assessing DRG cost accounting with respect to resource allocation and tariff calculation: the case of Germany.

    PubMed

    Vogl, Matthias

    2012-01-01

    The purpose of this paper is to analyze the German diagnosis related groups (G-DRG) cost accounting scheme by assessing its resource allocation at hospital level and its tariff calculation at national level. First, the paper reviews and assesses the three steps in the G-DRG resource allocation scheme at hospital level: (1) the groundwork; (2) cost-center accounting; and (3) patient-level costing. Second, the paper reviews and assesses the three steps in G-DRG national tariff calculation: (1) plausibility checks; (2) inlier calculation; and (3) the "one hospital" approach. The assessment is based on the two main goals of G-DRG introduction: improving transparency and efficiency. A further empirical assessment attests high costing quality. The G-DRG cost accounting scheme shows high system quality in resource allocation at hospital level, with limitations concerning a managerially relevant full cost approach and limitations in terms of advanced activity-based costing at patient-level. However, the scheme has serious flaws in national tariff calculation: inlier calculation is normative, and the "one hospital" model causes cost bias, adjustment and representativeness issues. The G-DRG system was designed for reimbursement calculation, but developed to a standard with strategic management implications, generalized by the idea of adapting a hospital's cost structures to DRG revenues. This combination causes problems in actual hospital financing, although resource allocation is advanced at hospital level. PMID:22935314

  18. [The DRG law--planning gone wrong? The conversion from the physician's point of view].

    PubMed

    Rochell, Bernhard; Roeder, Norbert

    2002-08-01

    With the Health Care Reform Act of 2000 the German government initiated the introduction of a new hospital funding system based on an internationally used Diagnosis Related Group (DRG) system. In June 2000, the medical self-governing bodies (consisting of representatives of the German Hospital Federation, the German Statutory Health Insurance Funds and the Association of Private Health Insurances) commissioned for the execution of this project decided to use the Australian Refined DRG system, version 4.1 (AR DRG) as the basis for the future German (Refined) DRG system (G-DRG). It is planned for voluntary hospitals to replace the previous German hospital reimbursement system by the new DRG-based hospital funding system in January 2003. From January 2004, the change of the reimbursement system will be mandatory for all hospitals with the exception of psychiatric, psychosomatic and psychotherapeutic hospitals or units. The new reimbursement system is not only intended to cover acute hospital care but also parts of early rehabilitation, palliative and sub-acute care. Due to its economic incentives the effects of introducing the DRG system in Germany will not only affect the hospital sector but ambulatory care, nursing and rehabilitation as well. PMID:12244873

  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

    PubMed Central

    Quartu, M.; Carozzi, V. A.; Dorsey, S. G.; Serra, M. P.; Poddighe, L.; Picci, C.; Boi, M.; Melis, T.; Del Fiacco, M.; Meregalli, C.; Chiorazzi, A.; Renn, C. L.; Cavaletti, G.; Marmiroli, P.

    2014-01-01

    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. PMID:24877063

  20. Carbon disulfide inhibits neurite outgrowth and neuronal migration of dorsal root ganglion in vitro.

    PubMed

    Ding, Ning; Xiang, Yujuan; Jiang, Hao; Zhang, Weiwei; Liu, Huaxiang; Li, Zhenzhong

    2011-12-01

    Carbon disulfide (CS₂) is a neurotoxic industrial solvent and widely used in the vulcanization of rubber, rayon, cellophane, and adhesives. Although the neurotoxicity of CS₂ has been recognized for over a century, the precise mechanism of neurotoxic action of CS₂ remains unknown. In the present study, a embryonic rat dorsal root ganglia (DRG) explants culture model was established. Using the organotypic DRG cultures, the direct neurotoxic effects of CS₂ on outgrowth of neurites and migration of neurons from DRG explants were investigated. The organotypic DRG cultures were exposed to different concentrations of CS₂ (0.01 mmol/L, 0.1 mmol/L, 1 mmol/L). The number of nerve fiber bundles extended from DRG explants decreased significantly in the presence of CS₂ (0.01 mmol/L, 15.00 ± 2.61, p < .05; 0.1 mmol/L, 11.17 ± 1.47, p < .001; 1 mmol/L, 8.00 ± 1.41, p < .001) as compared with that in the absence of CS₂ (17.83 ± 2.48). The number of neurons migrated from DRG explants decreased significantly in the presence of CS₂ (0.01 mmol/L, 79.50 ± 9.40, p < .01; 0.1 mmol/L, 62.50 ± 14.15, p < .001; 1 mmol/L, 34.67 ± 7.58, p < .001) as compared with that in the absence of CS₂ (99.33 ± 15.16). And also, the decreases in the number of nerve fiber bundles and migrated DRG neurons were in a dose-dependent manner of CS₂. These data implicated that CS₂ could inhibit neurite outgrowth and neuronal migration from DRG explants in vitro. PMID:21777162

  1. Pax6 Is Essential for the Maintenance and Multi-Lineage Differentiation of Neural Stem Cells, and for Neuronal Incorporation into the Adult Olfactory Bulb

    PubMed Central

    Curto, Gloria G.; Nieto-Estévez, Vanesa; Hurtado-Chong, Anahí; Valero, Jorge; Gómez, Carmela; Alonso, José R.; Weruaga, Eduardo

    2014-01-01

    The paired type homeobox 6 (Pax6) transcription factor (TF) regulates multiple aspects of neural stem cell (NSC) and neuron development in the embryonic central nervous system. However, less is known about the role of Pax6 in the maintenance and differentiation of adult NSCs and in adult neurogenesis. Using the +/SeyDey mouse, we have analyzed how Pax6 heterozygosis influences the self-renewal and proliferation of adult olfactory bulb stem cells (aOBSCs). In addition, we assessed its influence on neural differentiation, neuronal incorporation, and cell death in the adult OB, both in vivo and in vitro. Our results indicate that the Pax6 mutation alters Nestin+-cell proliferation in vivo, as well as self-renewal, proliferation, and survival of aOBSCs in vitro although a subpopulation of +/SeyDey progenitors is able to expand partially similar to wild-type progenitors. This mutation also impairs aOBSC differentiation into neurons and oligodendrocytes, whereas it increases cell death while preserving astrocyte survival and differentiation. Furthermore, Pax6 heterozygosis causes a reduction in the variety of neurochemical interneuron subtypes generated from aOBSCs in vitro and in the incorporation of newly generated neurons into the OB in vivo. Our findings support an important role of Pax6 in the maintenance of aOBSCs by regulating cell death, self-renewal, and cell fate, as well as in neuronal incorporation into the adult OB. They also suggest that deregulation of the cell cycle machinery and TF expression in aOBSCs which are deficient in Pax6 may be at the origin of the phenotypes observed in this adult NSC population. PMID:25117830

  2. Pre- and postnatal enzyme analysis for infantile, late infantile and adult neuronal ceroid lipofuscinosis (CLN1 and CLN2).

    PubMed

    Van Diggelen, O P; Keulemans, J L; Kleijer, W J; Thobois, S; Tilikete, C; Voznyi, Y V

    2001-01-01

    The recent development of simple, fluorogenic enzyme assays for infantile and late infantile neuronal ceroid lipofuscinosis (INCL and LINCL; CLN1 and CLN2) has greatly facilitated the diagnostic process for these diseases. In leucocytes and fibroblasts from INCL (n = 38) patients we found profound deficiencies of palmitoyl-protein thioesterase I (PPT1), the residual activity was < 5% of mean control activity. In fibroblasts from LINCL patients we found a similar deficiency of tripeptidyl-peptidase I activity (TPP-I), with < 2% activity in 16 patients. The residual TPP-I activity in leucocytes from LINCL patients seemed substantially higher. We also showed the feasibility of reliable prenatal enzyme analysis. In five first-trimester and two second-trimester prenatal analyses for INCL, four affected foetuses were detected (PPT activity 3-6%). Two first trimester pregnancies at risk for LINCL were analysed and a clear TPP-I deficiency was detected in both cases (TPP-I activity 3-4%). The first patient with adult neuronal ceroid lipofuscinosis (ANCL) due to a deficiency of PPT is presented; her present age is 53 years and the onset of the disease was at 38 years with psychiatric symptoms. PMID:11588995

  3. Short-lived diabetes in the young-adult ZDF rat does not exacerbate neuronal Ca(2+) biomarkers of aging.

    PubMed

    Maimaiti, Shaniya; DeMoll, Chris; Anderson, Katie L; Griggs, Ryan B; Taylor, Bradley K; Porter, Nada M; Thibault, Olivier

    2015-09-24

    Results from clinical studies provide evidence that cognitive changes relatively late in life may be traced to antecedent conditions including diabetes, obesity, a sedentary lifestyle, and an atherogenic diet. As such, several traits of Type 2 diabetes (T2DM) could be considered pathogenic factors of aging, contributing to age-dependent cognitive decline and our susceptibility to Alzheimer's disease. It appears that both the duration of metabolic condition and the age of the individual, together can contribute to the potential impact on peripheral as well as brain health. Because of robust evidence that in animal models of aging, Ca(2+) dysregulation alters neuronal health, synaptic plasticity, and learning and memory processes, we tested the hypothesis that peripheral metabolic dysregulation could exacerbate Ca(2+) dysfunction in hippocampal CA1 neurons. Using intracellular/ extracellular electrophysiological and Ca(2+) imaging techniques, we show that Ca(2+)levels at rest or during synaptic stimulation, the Ca(2+)-dependent afterhyperpolarization, baseline field potentials, and short-term synaptic plasticity were not significantly altered in young-adult male Zucker diabetic fatty rats compare to their lean counterparts. Our observations suggest that early phases of T2DM characterized by high levels of glucose and insulin may be too transient to alter hippocampal CA1 physiology in this animal model of diabetes. These results are supported by clinical data showing that longer T2DM duration can have greater negative impact on cognitive functions. This article is part of a Special Issue entitled SI: Brain and Memory. PMID:25451110

  4. Impact of the Sensory Neurons on Melanoma Growth In Vivo.

    PubMed

    Keskinov, Anton A; Tapias, Victor; Watkins, Simon C; Ma, Yang; Shurin, Michael R; Shurin, Galina V

    2016-01-01

    Nerve endings are often identified within solid tumors, but their impact on the tumor growth and progression remains poorly understood. Emerging data suggests that the central nervous system may affect cancer development and spreading via the hypothalamic-pituitary-adrenal axis and autonomous nervous system. However, the role of the afferent sensory neurons in tumor growth is unclear, except some reports on perineural invasion in prostate and pancreatic cancer and cancer-related pain syndrome. Here, we provide the results of primary testing of the concept that the interaction between melanoma cells and sensory neurons may induce the formation of tumor-supporting microenvironment via attraction of immune regulatory cells by the tumor-activated dorsal root ganglion (DRG) neurons. We report that despite DRG cells not directly up-regulating proliferation of melanoma cells in vitro, presence of DRG neurons allows tumors to grow significantly faster in vivo. This effect has been associated with increased production of chemokines by tumor-activated DRG neurons and attraction of myeloid-derived suppressor cells both in vitro and in vivo. These initial proof-of-concept results justify further investigations of the sensory (afferent) nervous system in the context of tumorigenesis and the local protumorigenic immunoenvironment. PMID:27227315

  5. Impact of the Sensory Neurons on Melanoma Growth In Vivo

    PubMed Central

    Tapias, Victor; Watkins, Simon C.; Ma, Yang; Shurin, Michael R.; Shurin, Galina V.

    2016-01-01

    Nerve endings are often identified within solid tumors, but their impact on the tumor growth and progression remains poorly understood. Emerging data suggests that the central nervous system may affect cancer development and spreading via the hypothalamic-pituitary-adrenal axis and autonomous nervous system. However, the role of the afferent sensory neurons in tumor growth is unclear, except some reports on perineural invasion in prostate and pancreatic cancer and cancer-related pain syndrome. Here, we provide the results of primary testing of the concept that the interaction between melanoma cells and sensory neurons may induce the formation of tumor-supporting microenvironment via attraction of immune regulatory cells by the tumor-activated dorsal root ganglion (DRG) neurons. We report that despite DRG cells not directly up-regulating proliferation of melanoma cells in vitro, presence of DRG neurons allows tumors to grow significantly faster in vivo. This effect has been associated with increased production of chemokines by tumor-activated DRG neurons and attraction of myeloid-derived suppressor cells both in vitro and in vivo. These initial proof-of-concept results justify further investigations of the sensory (afferent) nervous system in the context of tumorigenesis and the local protumorigenic immunoenvironment. PMID:27227315

  6. Estradiol target neurons in the hypothalamic arcuate nucleus and lateral ventromedial nucleus of young adult, reproductively senescent, and monosodium glutamate-lesioned female golden hamsters

    SciTech Connect

    Blaha, G.C.; Lamperti, A.A.

    1983-09-01

    Histoautoradiographic methods were used to assess estrogen target neurons in the hypothalamic arcuate nucleus (ARC) and ventromedial nucleus, lateral portion (LVM), comparing young adult and aged female golden hamsters. A subgroup of young adult females had ARC lesions induced by monosodium glutamate at neonatal day 8. All were ovariectomized to remove endogenous estrogens. Controls were given nonradioactive estradiol. After /sup 3/H-estradiol (/sup 3/H-E2) was injected intravenously, hypothalami were removed, frozen, and processed for histoautoradiography. In the ARC and LVM the ratio of /sup 3/H-E2 labelled neurons to total neurons counted was significantly lower in the older animals. Young females with ARC lesions had very few /sup 3/H-E2 labelled neurons remaining in the ARC but had a normal complement in the LVM. Although /sup 3/H-E2 labelled ARC neurons were notably decreased in old females, those ARC neurons that were labelled in the old had virtually the same frequency distribution of the labelling index as in the young, suggesting no change in the average estrogen uptake per target cell.

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

    PubMed

    Nazıroğlu, M; Çiğ, B; Özgül, C

    2014-03-28

    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. PMID:24434769

  8. Voltage-Induced Ca2+ Release in Postganglionic Sympathetic Neurons in Adult Mice

    PubMed Central

    Sun, Hong-Li; Tsai, Wen-Chin; Li, Bai-Yan; Tao, Wen; Chen, Peng-Sheng; Rubart, Michael

    2016-01-01

    Recent studies have provided evidence that depolarization in the absence of extracellular Ca2+ can trigger Ca2+ release from internal stores in a variety of neuron subtypes. Here we examine whether postganglionic sympathetic neurons are able to mobilize Ca2+ from intracellular stores in response to depolarization, independent of Ca2+ influx. We measured changes in cytosolic ΔF/F0 in individual fluo-4 –loaded sympathetic ganglion neurons in response to maintained K+ depolarization in the presence (2 mM) and absence of extracellular Ca2+ ([Ca2+]e). Progressive elevations in extracellular [K+]e caused increasing membrane depolarizations that were of similar magnitude in 0 and 2 mM [Ca2+]e. Peak amplitude of ΔF/F0 transients in 2 mM [Ca2+]e increased in a linear fashion as the membrane become more depolarized. Peak elevations of ΔF/F0 in 0 mM [Ca2+]e were ~5–10% of those evoked at the same membrane potential in 2 mM [Ca2+]e and exhibited an inverse U-shaped dependence on voltage. Both the rise and decay of ΔF/F0 transients in 0 mM [Ca2+]e were slower than those of ΔF/F0 transients evoked in 2 mM [Ca2+]e. Rises in ΔF/F0 evoked by high [K+]e in the absence of extracellular Ca2+ were blocked by thapsigargin, an inhibitor of endoplasmic reticulum Ca2+ ATPase, or the inositol 1,4,5-triphosphate (IP3) receptor antagonists 2-aminoethoxydiphenyl borate and xestospongin C, but not by extracellular Cd2+, the dihydropyridine antagonist nifedipine, or by ryanodine at concentrations that caused depletion of ryanodine-sensitive Ca2+ stores. These results support the notion that postganglionic sympathetic neurons possess the ability to release Ca2+ from IP3-sensitive internal stores in response to membrane depolarization, independent of Ca2+ influx. PMID:26859144

  9. NGF signaling in sensory neurons: evidence that early endosomes carry NGF retrograde signals.

    PubMed

    Delcroix, Jean-Dominique; Valletta, Janice S; Wu, Chengbiao; Hunt, Stephen J; Kowal, Anthony S; Mobley, William C

    2003-07-01

    Target-derived NGF promotes the phenotypic maintenance of mature dorsal root ganglion (DRG) nociceptive neurons. Here, we provide in vivo and in vitro evidence for the presence within DRG neurons of endosomes containing NGF, activated TrkA, and signaling proteins of the Rap1/Erk1/2, p38MAPK, and PI3K/Akt pathways. Signaling endosomes were shown to be retrogradely transported in the isolated sciatic nerve in vitro. NGF injection in the peripheral target of DRG neurons increased the retrograde transport of p-Erk1/2, p-p38, and pAkt in these membranes. Conversely, NGF antibody injections decreased the retrograde transport of p-Erk1/2 and p-p38. Our results are evidence that signaling endosomes, with the characteristics of early endosomes, convey NGF signals from the target of nociceptive neurons to their cell bodies. PMID:12848933

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

    PubMed

    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

    2016-01-01

    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. PMID:26691752

  11. Neuronal reorganization in adult rats neonatally exposed to (±)-3,4-methylenedioxymethamphetamine

    PubMed Central

    Williams, Michael T.; Skelton, Matthew R.; Longacre, Ian D.; Huggins, Kimberly N.; Maple, Amanda M.; Vorhees, Charles V.; Brown, Russell W.

    2014-01-01

    The abuse of methylenedioxymethamphetamine (MDMA) during pregnancy is of concern. MDMA treatment of rats during a period of brain growth analogous to late human gestation leads to neurochemical and behavioral changes. MDMA from postnatal day (P)11–20 in rats produces reductions in serotonin and deficits in spatial and route-based navigation. In this experiment we examined the impact of MDMA from P11–20 (20 mg/kg twice daily, 8 h apart) on neuronal architecture. Golgi impregnated sections showed significant changes. In the nucleus accumbens, the dendrites were shorter with fewer spines, whereas in the dentate gyrus the dendritic length was decreased but with more spines, and for the entorhinal cortex, reductions in basilar and apical dendritic lengths in MDMA animals compared with saline animals were seen. The data show that neuronal cytoarchitectural changes are long-lasting following developmental MDMA exposure and are in regions consistent with the learning and memory deficits observed in such animals. PMID:25419515

  12. Sustaining intrinsic growth capacity of adult neurons promotes spinal cord regeneration

    NASA Astrophysics Data System (ADS)

    Neumann, Simona; Skinner, Kate; Basbaum, Allan I.

    2005-11-01

    The peripheral axonal branch of primary sensory neurons readily regenerates after peripheral nerve injury, but the central branch, which courses in the dorsal columns of the spinal cord, does not. However, if a peripheral nerve is transected before a spinal cord injury, sensory neurons that course in the dorsal columns will regenerate, presumably because their intrinsic growth capacity is enhanced by the priming peripheral nerve lesion. As the effective priming lesion is made before the spinal cord injury it would clearly have no clinical utility, and unfortunately, a priming lesion made after a spinal cord injury results in an abortive regenerative response. Here, we show that two priming lesions, one made at the time of a spinal cord injury and a second 1 week after a spinal cord injury, in fact, promote dramatic regeneration, within and beyond the lesion. The first lesion, we hypothesize, enhances intrinsic growth capacity, and the second one sustains it, providing a paradigm for promoting CNS regeneration after injury. primary afferents | dorsal columns | neurite outgrowth | sprouting | priming

  13. Increased BrdU incorporation reflecting DNA repair, neuronal de-differentiation or possible neurogenesis in the adult cochlear nucleus following bilateral cochlear lesions in the rat.

    PubMed

    Zheng, Yiwen; Begum, Shaeza; Zhang, Chu; Fleming, Kirk; Masumura, Chisako; Zhang, Ming; Smith, Paul; Darlington, Cynthia

    2011-05-01

    Neurogenesis is known to occur in response to injury in the brain, for example, as a result of neurodegenerative diseases. However, there have been few investigations into how the brain responds to damage to peripheral sensory nerves, in other areas such as the brainstem. Here, we report that bilateral surgical lesions of the cochlea result in increased incorporation of the DNA replication marker, bromodeoxyuridine (BrdU), in cells of the brainstem cochlear nucleus (CN) of the adult rat, suggesting either cell proliferation or DNA repair. Some of the BrdU-labelled cells colabelled for the mature neuron marker, NeuN and the GABAergic enzyme GAD-65, suggesting the possibility that neurogenesis might have occurred and resulted in the generation of new neurons with a GABAergic phenotype. However, some of the mature neurons also re-expressed immature neuronal intermediate filament and microtuble-associated proteins, without apoptotic neuronal death, which suggests that the colabelling of BrdU with NeuN and GAD-65 may not be a true reflection of neurogenesis, but injury-stimulated neuronal dedifferentiation. These results suggest the possibility that DNA repair, neuronal de-differentiation or possible neurogenesis occurs in the cochlear nucleus, in response to damage to the peripheral auditory system. PMID:21104237

  14. Acute stress enhances adult rat hippocampal neurogenesis and activation of newborn neurons via secreted astrocytic FGF2

    PubMed Central

    Kirby, Elizabeth D; Muroy, Sandra E; Sun, Wayne G; Covarrubias, David; Leong, Megan J; Barchas, Laurel A; Kaufer, Daniela

    2013-01-01

    Stress is a potent modulator of the mammalian brain. The highly conserved stress hormone response influences many brain regions, particularly the hippocampus, a region important for memory function. The effect of acute stress on the unique population of adult neural stem/progenitor cells (NPCs) that resides in the adult hippocampus is unclear. We found that acute stress increased hippocampal cell proliferation and astrocytic fibroblast growth factor 2 (FGF2) expression. The effect of acute stress occurred independent of basolateral amygdala neural input and was mimicked by treating isolated NPCs with conditioned media from corticosterone-treated primary astrocytes. Neutralization of FGF2 revealed that astrocyte-secreted FGF2 mediated stress-hormone-induced NPC proliferation. 2 weeks, but not 2 days, after acute stress, rats also showed enhanced fear extinction memory coincident with enhanced activation of newborn neurons. Our findings suggest a beneficial role for brief stress on the hippocampus and improve understanding of the adaptive capacity of the brain. DOI: http://dx.doi.org/10.7554/eLife.00362.001 PMID:23599891

  15. Issues for comparability of DRG statistics in Europe. Results from EURODRG.

    PubMed

    Casas, M

    1991-03-01

    DRG use has spread through most European countries thus offering an opportunity for improving hospital data bases at the European level. An EEC Concerted Action 'Use of DRGs to support Hospital Sector Management in the European Community' was approved by the Committee of Health Services Research of the EEC. A general overview of the project is presented as well as a detailed description of the results of the work on aspects related to DRG data production. These aspects (MBDS implementation and variables definition; coding systems and updating; mapping systems; data auditing; trimming methods; and DRG grouper versions) have been analyzed with the objective of increasing opportunities for valid international comparisons of DRG statistics between European countries. PMID:10170739

  16. Glutamate/glutamine and neuronal integrity in adults with ADHD: a proton MRS study

    PubMed Central

    Maltezos, S; Horder, J; Coghlan, S; Skirrow, C; O'Gorman, R; Lavender, T J; Mendez, M A; Mehta, M; Daly, E; Xenitidis, K; Paliokosta, E; Spain, D; Pitts, M; Asherson, P; Lythgoe, D J; Barker, G J; Murphy, D G

    2014-01-01

    There is increasing evidence that abnormalities in glutamate signalling may contribute to the pathophysiology of attention-deficit hyperactivity disorder (ADHD). Proton magnetic resonance spectroscopy ([1H]MRS) can be used to measure glutamate, and also its metabolite glutamine, in vivo. However, few studies have investigated glutamate in the brain of adults with ADHD naive to stimulant medication. Therefore, we used [1H]MRS to measure the combined signal of glutamate and glutamine (Glu+Gln; abbreviated as Glx) along with other neurometabolites such as creatine (Cr), N-acetylaspartate (NAA) and choline. Data were acquired from three brain regions, including two implicated in ADHD—the basal ganglia (caudate/striatum) and the dorsolateral prefrontal cortex (DLPFC)—and one ‘control' region—the medial parietal cortex. We compared 40 adults with ADHD, of whom 24 were naive for ADHD medication, whereas 16 were currently on stimulants, against 20 age, sex and IQ-matched healthy controls. We found that compared with controls, adult ADHD participants had a significantly lower concentration of Glx, Cr and NAA in the basal ganglia and Cr in the DLPFC, after correction for multiple comparisons. There were no differences between stimulant-treated and treatment-naive ADHD participants. In people with untreated ADHD, lower basal ganglia Glx was significantly associated with more severe symptoms of inattention. There were no significant differences in the parietal ‘control' region. We suggest that subcortical glutamate and glutamine have a modulatory role in ADHD adults; and that differences in glutamate–glutamine levels are not explained by use of stimulant medication. PMID:24643164

  17. Glutamate/glutamine and neuronal integrity in adults with ADHD: a proton MRS study.

    PubMed

    Maltezos, S; Horder, J; Coghlan, S; Skirrow, C; O'Gorman, R; Lavender, T J; Mendez, M A; Mehta, M; Daly, E; Xenitidis, K; Paliokosta, E; Spain, D; Pitts, M; Asherson, P; Lythgoe, D J; Barker, G J; Murphy, D G

    2014-01-01

    There is increasing evidence that abnormalities in glutamate signalling may contribute to the pathophysiology of attention-deficit hyperactivity disorder (ADHD). Proton magnetic resonance spectroscopy ([1H]MRS) can be used to measure glutamate, and also its metabolite glutamine, in vivo. However, few studies have investigated glutamate in the brain of adults with ADHD naive to stimulant medication. Therefore, we used [1H]MRS to measure the combined signal of glutamate and glutamine (Glu+Gln; abbreviated as Glx) along with other neurometabolites such as creatine (Cr), N-acetylaspartate (NAA) and choline. Data were acquired from three brain regions, including two implicated in ADHD-the basal ganglia (caudate/striatum) and the dorsolateral prefrontal cortex (DLPFC)-and one 'control' region-the medial parietal cortex. We compared 40 adults with ADHD, of whom 24 were naive for ADHD medication, whereas 16 were currently on stimulants, against 20 age, sex and IQ-matched healthy controls. We found that compared with controls, adult ADHD participants had a significantly lower concentration of Glx, Cr and NAA in the basal ganglia and Cr in the DLPFC, after correction for multiple comparisons. There were no differences between stimulant-treated and treatment-naive ADHD participants. In people with untreated ADHD, lower basal ganglia Glx was significantly associated with more severe symptoms of inattention. There were no significant differences in the parietal 'control' region. We suggest that subcortical glutamate and glutamine have a modulatory role in ADHD adults; and that differences in glutamate-glutamine levels are not explained by use of stimulant medication. PMID:24643164

  18. Allotransplanted Neurons Used to Repair Peripheral Nerve Injury Do Not Elicit Overt Immunogenicity

    PubMed Central

    Liu, Weimin; Ren, Yi; Bossert, Adam; Wang, Xiaowei; Dayawansa, Samantha; Tong, Jing; He, Xiaoshen; Smith, Douglas H.; Gelbard, Harris A.; Huang, Jason H.

    2012-01-01

    A major problem hindering the development of autograft alternatives for repairing peripheral nerve injuries is immunogenicity. We have previously shown successful regeneration in transected rat sciatic nerves using conduits filled with allogeneic dorsal root ganglion (DRG) cells without any immunosuppression. In this study, we re-examined the immunogenicity of our DRG neuron implanted conduits as a potential strategy to overcome transplant rejection. A biodegradable NeuraGen® tube was infused with pure DRG neurons or Schwann cells cultured from a rat strain differing from the host rats and used to repair 8 mm gaps in the sciatic nerve. We observed enhanced regeneration with allogeneic cells compared to empty conduits 16 weeks post-surgery, but morphological analyses suggest recovery comparable to the healthy nerves was not achieved. The degree of regeneration was indistinguishable between DRG and Schwann cell allografts although immunogenicity assessments revealed substantially increased presence of Interferon gamma (IFN-γ) in Schwann cell allografts compared to the DRG allografts by two weeks post-surgery. Macrophage infiltration of the regenerated nerve graft in the DRG group 16 weeks post-surgery was below the level of the empty conduit (0.56 fold change from NG; p<0.05) while the Schwann cell group revealed significantly higher counts (1.29 fold change from NG; p<0.001). Major histocompatibility complex I (MHC I) molecules were present in significantly increased levels in the DRG and Schwann cell allograft groups compared to the hollow NG conduit and the Sham healthy nerve. Our results confirmed previous studies that have reported Schwann cells as being immunogenic, likely due to MHC I expression. Nerve gap injuries are difficult to repair; our data suggest that DRG neurons are superior medium to implant inside conduit tubes due to reduced immunogenicity and represent a potential treatment strategy that could be preferable to the current gold standard of

  19. Propofol and AZD3043 Inhibit Adult Muscle and Neuronal Nicotinic Acetylcholine Receptors Expressed in Xenopus Oocytes

    PubMed Central

    Jonsson Fagerlund, Malin; Krupp, Johannes; Dabrowski, Michael A.

    2016-01-01

    Propofol is a widely used general anaesthetic with muscle relaxant properties. Similarly as propofol, the new general anaesthetic AZD3043 targets the GABAA receptor for its anaesthetic effects, but the interaction with nicotinic acetylcholine receptors (nAChRs) has not been investigated. Notably, there is a gap of knowledge about the interaction between propofol and the nAChRs found in the adult neuromuscular junction. The objective was to evaluate whether propofol or AZD3043 interact with the α1β1δε, α3β2, or α7 nAChR subtypes that can be found in the neuromuscular junction and if there are any differences in affinity for those subtypes between propofol and AZD3043. Human nAChR subtypes α1β1δε, α3β2, and α7 were expressed into Xenopus oocytes and studied with an automated voltage-clamp. Propofol and AZD3043 inhibited ACh-induced currents in all of the nAChRs studied with inhibitory concentrations higher than those needed for general anaesthesia. AZD3043 was a more potent inhibitor at the adult muscle nAChR subtype compared to propofol. Propofol and AZD3043 inhibit nAChR subtypes that can be found in the adult NMJ in concentrations higher than needed for general anaesthesia. This finding needs to be evaluated in an in vitro nerve-muscle preparation and suggests one possible explanation for the muscle relaxant effect of propofol seen during higher doses. PMID:26861354

  20. Odour enrichment increases adult-born dopaminergic neurons in the mouse olfactory bulb.

    PubMed

    Bonzano, Sara; Bovetti, Serena; Fasolo, Aldo; Peretto, Paolo; De Marchis, Silvia

    2014-11-01

    The olfactory bulb (OB) is the first brain region involved in the processing of olfactory information. In adult mice, the OB is highly plastic, undergoing cellular/molecular dynamic changes that are modulated by sensory experience. Odour deprivation induces down-regulation of tyrosine hydroxylase (TH) expression in OB dopaminergic interneurons located in the glomerular layer (GL), resulting in decreased dopamine in the OB. Although the effect of sensory deprivation is well established, little is known about the influence of odour enrichment on dopaminergic cells. Here we report that prolonged odour enrichment on C57BL/6J strain mice selectively increases TH-immunopositive cells in the GL by nearly 20%. Following odour enrichment on TH-green fluorescent protein (GFP) transgenic mice, in which GFP identified both mature TH-positive cells and putative immature dopaminergic cells expressing TH mRNA but not TH protein, we found a similar 20% increase in GFP-expressing cells, with no changes in the ratio between TH-positive and TH-negative cells. These data suggest that enriched conditions induce an expansion in the whole dopaminergic lineage. Accordingly, by using 5-bromo-2-deoxyuridine injections to label adult-generated cells in the GL of TH-GFP mice, we found an increase in the percentage of 5-bromo-2-deoxyuridine-positive dopaminergic cells in enriched compared with control conditions, whereas no differences were found for calretinin- and calbindin-positive subtypes. Strikingly, the fraction of newborn cells among the dopaminergic population doubled in enriched conditions. On the whole, our results demonstrate that odour enrichment drives increased integration of adult-generated dopaminergic cells that could be critical to adapt the OB circuits to the environmental incoming information. PMID:25216299

  1. Spontaneous neuronal activity in insula predicts symptom severity of unmedicated obsessive compulsive disorder adults.

    PubMed

    Zhu, Y; Fan, Q; Zhang, Z; Zhang, H; Tong, S; Li, Y

    2015-01-01

    Emerging evidence has suggested that the pathophysiology of obsessive compulsive disorder (OCD) might involve widely distributed large-scale brain systems. The dysfunction within salience network, which is comprised of dorsal anterior cingulated cortex (dACC) and bilateral insular areas, has been proposed to contribute to OCD onset. The mechanism underlying salience network abnormality remains unclear and it is worthwhile to investigate its clinical relevance using functional neuroimaging approaches. In this study, we performed the spontaneous brain activity measurement using resting-state functional magnetic resonance imaging (fMRI) on unmedicated OCD patients (n=23). Specifically, the amplitude of low frequency (0.01-0.08 Hz) fluctuations (ALFF) was calculated for regions in salience network. The voxel-based Pearson's correlative analysis was conducted to explore the relationship beween ALFF measures and symptom severity for OCD patients. The results showed that the spontaneous neuronal activity in insula was significantly correlated to OCD clinical symptoms, especially compulsive behaviors. Our findings consolidated that the salience network played an important role in the pathogenesis of OCD and the intensity of intrinsic brain activity in insula provided a predictive biomarker for OCD symptom severity. PMID:26737523

  2. Social experience affects neuronal responses to male calls in adult female zebra finches.

    PubMed

    Menardy, F; Touiki, K; Dutrieux, G; Bozon, B; Vignal, C; Mathevon, N; Del Negro, C

    2012-04-01

    Plasticity studies have consistently shown that behavioural relevance can change the neural representation of sounds in the auditory system, but what occurs in the context of natural acoustic communication where significance could be acquired through social interaction remains to be explored. The zebra finch, a highly social songbird species that forms lifelong pair bonds and uses a vocalization, the distance call, to identify its mate, offers an opportunity to address this issue. Here, we recorded spiking activity in females while presenting distance calls that differed in their degree of familiarity: calls produced by the mate, by a familiar male, or by an unfamiliar male. We focused on the caudomedial nidopallium (NCM), a secondary auditory forebrain region. Both the mate's call and the familiar call evoked responses that differed in magnitude from responses to the unfamiliar call. This distinction between responses was seen both in single unit recordings from anesthetized females and in multiunit recordings from awake freely moving females. In contrast, control females that had not heard them previously displayed responses of similar magnitudes to all three calls. In addition, more cells showed highly selective responses in mated than in control females, suggesting that experience-dependent plasticity in call-evoked responses resulted in enhanced discrimination of auditory stimuli. Our results as a whole demonstrate major changes in the representation of natural vocalizations in the NCM within the context of individual recognition. The functional properties of NCM neurons may thus change continuously to adapt to the social environment. PMID:22512260

  3. Adult onset motor neuron disease: worldwide mortality, incidence and distribution since 1950.

    PubMed Central

    Chancellor, A M; Warlow, C P

    1992-01-01

    This review examines the commonly held premise that, apart from the Western Pacific forms, motor neuron disease (MND), has a uniform worldwide distribution in space and time; the methodological problems in studies of MND incidence; and directions for future epidemiological research. MND is more common in men at all ages. Age-specific incidence rises steeply into the seventh decade but the incidence in the very elderly is uncertain. A rise in mortality from MND over recent decades has been demonstrated wherever this has been examined and may be real rather than due to improved case ascertainment. Comparison of incidence studies in different places is complicated by non-standardised methods of case ascertainment and diagnosis but there appear to be differences between well studied populations. In developed countries in the northern hemisphere there is a weak positive correlation between standardised, age-specific incidence and distance from the equator. There is now strong evidence for an environmental factor as the cause of the Western Pacific forms of MND. A number of clusters of sporadic MND have been reported from developed countries, but no single agent identified as responsible. Images PMID:1479386

  4. Regulation of Voltage-Gated Ca2+ Currents by Ca2+/Calmodulin-dependent Protein Kinase II in Resting Sensory Neurons

    PubMed Central

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

    2014-01-01

    Calcium/calmodulin-dependent protein kinase II (CaMKII) is recognized as a key element in encoding depolarization activity of excitable cells into facilitated voltage-gated Ca2+ channel (VGCC) function. Less is known about the participation of CaMKII in regulating VGCCs in resting cells. We examined constitutive CaMKII control of Ca2+ 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 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. PMID:25064143

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

    PubMed

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

    2014-09-01

    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. PMID:25064143

  6. Nociceptin/orphanin FQ receptor expression in clinical pain disorders and functional effects in cultured neurons.

    PubMed

    Anand, Praveen; Yiangou, Yiangos; Anand, Uma; Mukerji, Gaurav; Sinisi, Marco; Fox, Michael; McQuillan, Anthony; Quick, Tom; Korchev, Yuri E; Hein, Peter

    2016-09-01

    The nociceptin/orphanin FQ peptide receptor (NOP), activated by its endogenous peptide ligand nociceptin/orphanin FQ (N/OFQ), exerts several effects including modulation of pain signalling. We have examined, for the first time, the tissue distribution of the NOP receptor in clinical visceral and somatic pain disorders by immunohistochemistry and assessed functional effects of NOP and μ-opioid receptor activation in cultured human and rat dorsal root ganglion (DRG) neurons. Quantification of NOP-positive nerve fibres within the bladder suburothelium revealed a remarkable several-fold increase in detrusor overactivity (P < 0.0001) and painful bladder syndrome patient specimens (P = 0.0014) compared with controls. In postmortem control human DRG, 75% to 80% of small/medium neurons (≤50 μm diameter) in the lumbar (somatic) and sacral (visceral) DRG were positive for NOP, and fewer large neurons; avulsion-injured cervical human DRG neurons showed similar numbers. NOP immunoreactivity was significantly decreased in injured peripheral nerves (P = 0.0004), and also in painful neuromas (P = 0.025). Calcium-imaging studies in cultured rat DRG neurons demonstrated dose-dependent inhibition of capsaicin responses in the presence of N/OFQ, with an IC50 of 8.6 pM. In cultured human DRG neurons, 32% inhibition of capsaicin responses was observed in the presence of 1 pM N/OFQ (P < 0.001). The maximum inhibition of capsaicin responses was greater with N/OFQ than μ-opioid receptor agonist DAMGO. Our findings highlight the potential of NOP agonists, particularly in urinary bladder overactivity and pain syndromes. The regulation of NOP expression in visceral and somatic sensory neurons by target-derived neurotrophic factors deserves further study, and the efficacy of NOP selective agonists in clinical trials. PMID:27127846

  7. Calcium-binding protein parvalbumin-immunoreactive neurons in the rat olfactory bulb. 1. Distribution and structural features in adult rat.

    PubMed

    Kosaka, K; Heizmann, C W; Kosaka, T

    1994-01-01

    The laminar distribution and morphological features of parvalbumin-immunoreactive [PV(+)] neurons, one of the subpopulations of GABAergic neurons, were studied in the rat olfactory bulb at a light microscopic level. In the main olfactory bulb of adult rats, PV(+) neurons were mainly located in the external plexiform layer (EPL), and a few were scattered in the glomerular layer (GL), mitral cell layer (ML), and granule cell layer (GRL); whereas PV(+) neurons were rarely seen in the accessory olfactory bulb. The inner and outer sublayers of the EPL (ISL and OSL) appeared to be somewhat different in the distribution of PV(+) somata and features of PV(+) processes. PV(+) somata were located throughout the OSL, and PV(+) processes intermingled with one another, making a dense meshwork in the OSL; whereas, in the ISL, PV(+) somata were mainly located near the inner border of the EPL, and PV(+) processes made a sparser meshwork than that in the OSL. PV(+) neurons in the EPL were apparently heterogeneous in their structural features and appeared to be classifiable into several groups. Among them there appeared five distinctive types of PV(+) neurons. The most prominent group of PV(+) neurons in the OSL were superficial short-axon cells, located in the superficial portion of this sublayer and giving rise to relatively thick processes, in horizontal or oblique directions, which usually bore spines and varicosities. Another prominent group of PV(+) neurons extended several short, branched dendrites with spines and varicosities, which appeared to intermingle with one another, making a relatively small, spherical or ovoid dendritic field around the cell bodies; most of them resembled Van Gehuchten cells reported in previous Golgi studies. A third distinctive and most numerous group of PV(+) neurons were of the multipolar type; their somata and processes were located throughout the EPL. Their relatively smooth processes with frequent varicosities and a few spines were extended

  8. Exome-Sequencing Confirms DNAJC5 Mutations as Cause of Adult Neuronal Ceroid-Lipofuscinosis

    PubMed Central

    Benitez, Bruno A.; Alvarado, David; Cai, Yefei; Mayo, Kevin; Chakraverty, Sumitra; Norton, Joanne; Morris, John C.; Sands, Mark S.; Goate, Alison; Cruchaga, Carlos

    2011-01-01

    We performed whole-exome sequencing in two autopsy-confirmed cases and an elderly unaffected control from a multigenerational family with autosomal dominant neuronal ceroid lipofuscinosis (ANCL). A novel single-nucleotide variation (c.344T>G) in the DNAJC5 gene was identified. Mutational screening in an independent family with autosomal dominant ANCL found an in-frame single codon deletion (c.346_348 delCTC) resulting in a deletion of p.Leu116del. These variants fulfill all genetic criteria for disease-causing mutations: they are found in unrelated families with the same disease, exhibit complete segregation between the mutation and the disease, and are absent in healthy controls. In addition, the associated amino acid substitutions are located in evolutionarily highly conserved residues and are predicted to functionally affect the encoded protein (CSPα). The mutations are located in a cysteine-string domain, which is required for membrane targeting/binding, palmitoylation, and oligomerization of CSPα. We performed a comprehensive in silico analysis of the functional and structural impact of both mutations on CSPα. We found that these mutations dramatically decrease the affinity of CSPα for the membrane. We did not identify any significant effect on palmitoylation status of CSPα. However, a reduction of CSPα membrane affinity may change its palmitoylation and affect proper intracellular sorting. We confirm that CSPα has a strong intrinsic aggregation propensity; however, it is not modified by the mutations. A complementary disease-network analysis suggests a potential interaction with other NCLs genes/pathways. This is the first replication study of the identification of DNAJC5 as the disease-causing gene for autosomal dominant ANCL. The identification of the novel gene in ANCL will allow us to gain a better understanding of the pathological mechanism of ANCLs and constitutes a great advance toward the development of new molecular diagnostic tests and may

  9. Increased vitamin D receptor expression in dorsal root ganglia neurons of diabetic rats.

    PubMed

    Filipović, Natalija; Ferhatović, Lejla; Marelja, Ivana; Puljak, Livia; Grković, Ivica

    2013-08-01

    The effects of vitamin D on the nervous system have been studied extensively. In spite of accumulating data about the substantial changes in the vitamin D receptor (VDR) signaling system, during different types of neuroinflammatory diseases, its role in diabetic neuropathy has not been investigated in detail. To assess the role of VDR signaling in diabetic neuropathy, we examined expression of VDRs in dorsal root ganglia (DRG) neurons in a rat model of streptozotocin-induced diabetes mellitus type 1. Diabetes mellitus (DM) type 1 was induced with streptozotocin in male Sprague-Dawley rats. After two months, expression of VDRs was analyzed immunohistochemically in the cytoplasm of L4 and L5 DRG neurons of diabetic rats. Semi-quantitative analysis for the determination of staining in nuclei and plasma-membranes of DRG neurons was performed. A significant increase in VDR expression was observed in DRG neurons of diabetic rats. Expression of VDRs was increased in the cytoplasm, nuclei and in cell membranes of neurons. An increase in VDR expression occurred in all neurons, but the greatest increase of fluorescence intensity in cytoplasm was observed in neurons of small diameter. Results of the present study indicate that the VDR signaling system could be a potential therapeutic target for diabetic neuropathy. PMID:23684983

  10. Data quality in a DRG-based information system.

    PubMed

    Colin, C; Ecochard, R; Delahaye, F; Landrivon, G; Messy, P; Morgon, E; Matillon, Y

    1994-09-01

    The aim of this study initiated in May 1990 was to evaluate the quality of the medical data collected from the main hospital of the "Hospices Civils de Lyon", Edouard Herriot Hospital. We studied a random sample of 593 discharge abstracts from 12 wards of the hospital. Quality control was performed by checking multi-hospitalized patients' personal data, checking that each discharge abstract was exhaustive, examining the quality of abstracting, studying diagnoses and medical procedures coding, and checking data entry. Assessment of personal data showed a 4.4% error rate. It was mainly accounted for by spelling mistakes in surnames and first names, and mistakes in dates of birth. The quality of a discharge abstract was estimated according to the two purposes of the medical information system: description of hospital morbidity per patient and Diagnosis Related Group's case mix. Error rates in discharge abstracts were expressed in two ways: an overall rate for errors of concordance between Discharge Abstracts and Medical Records, and a specific rate for errors modifying classification in Diagnosis Related Groups (DRG). For abstracting medical information, these error rates were 11.5% (SE +/- 2.2) and 7.5% (SE +/- 1.9) respectively. For coding diagnoses and procedures, they were 11.4% (SE +/- 1.5) and 1.3% (SE +/- 0.5) respectively. For data entry on the computerized data base, the error rate was 2% (SE +/- 0.5) and 0.2% (SE +/- 0.05). Quality control must be performed regularly because it demonstrates the degree of participation from health care teams and the coherence of the database.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7795964

  11. Sex Differences and Effects of Prenatal Exposure to Excess Testosterone on Ventral Tegmental Area Dopamine Neurons in Adult Sheep

    PubMed Central

    Brown, Erinna C. Z.; Steadman, Casey J.; Lee, Theresa M.; Padmanabhan, Vasantha; Lehman, Michael N.; Coolen, Lique M.

    2015-01-01

    Prenatal testosterone (T) excess in sheep results in a wide array of reproductive neuroendocrine deficits and alterations in motivated behavior. The ventral tegmental area (VTA) plays a critical role in reward and motivated behaviors and is hypothesized to be targeted by prenatal T. Here we report a sex difference in the number VTA dopamine cells in the adult sheep with higher numbers of tyrosine hydroxylase (TH)-immunoreactive cells in males than females. Moreover, prenatal exposure to excess T during either gestational days 30–90 or 60–90 resulted in increased numbers of VTA TH- immunoreactive cells in adult ewes compared to control females. Stereological analysis confirmed significantly greater numbers of neurons in the VTA of males and prenatal T-treated ewes, which was primarily accounted for by greater numbers of TH-immunoreactive cells. In addition, immunoreactivity for TH in the cells was denser in males and prenatal T-treated females, suggesting that sex differences and prenatal exposure to excess T affects both numbers of cells expressing TH as well as the protein levels with dopamine cells. Sex differences were also noted in numbers of TH-immunoreactive cells in the substantia nigra, with more cells in males than females. However, prenatal exposure to excess T did not affect numbers of TH-immunoreactive cells in the substantia nigra, suggesting that this sex difference is organized independently from prenatal actions of T. Together, these results demonstrate sex differences in the sheep VTA dopamine system which are mimicked by prenatal treatment with excess T. PMID:25784297

  12. An in vitro assay system for studying synapse formation between nociceptive dorsal root ganglion and dorsal horn neurons

    PubMed Central

    Joseph, Donald J.; Choudhury, Papiya; MacDermott, Amy B.

    2010-01-01

    Synapses between nociceptive dorsal root ganglion (DRG) neurons and spinal cord dorsal horn neurons represent the first loci for transmission of painful stimuli. Our knowledge of the molecular organization and development of these synapses is sparse due, partly, to a lack of a reliable model system that reconstitutes synaptogenesis between these two neuronal populations. To address this issue, we have established an in vitro assay system consisting of separately purified DRG neurons and dorsal horn neurons on astrocyte micro-islands. Using immunocytochemistry, we have found that 97%, 93%, 98%, 96%, and 94% of DRG neurons on these microislands express markers often associated with nociceptive neurons including Substance P, TRPV1, calcitonin-gene related peptide (CGRP), TrKA, and peripherin, respectively. Triple labeling with these nociceptive-like markers, synaptic vesicle marker Vglut2 and using MAP2 as a dendritic marker revealed the presence of nociceptive-like markers at synaptic terminals. Using this immunocytochemical approach, we counted contact points as overlapping MAP2/Vglut2 puncta and showed that they increased with time in culture. Single and dual patch clamp recordings showed that overlapping Vglut2/MAP2 puncta observed after a few days in culture are likely to be functional synapses between DRG and dorsal horn neurons in our in vitro assay system. Taken together, these data suggest our co-culture microisland model system consists of mostly nociceptive-like DRG neurons that express presynaptic markers and form functional synapses with their dorsal horn partners. Thus, this model system may have direct application for studies on factors regulating development of nociceptive DRG/dorsal horn synapses. PMID:20385165

  13. Neurocalcin-immunoreactive neurons in the mammalian dorsal root ganglia, including humans.

    PubMed

    Galeano, R; Germanà, A; Abbate, F; Calvo, D; Naves, F J; Hidaka, H; Germanà, G; Vega, J A

    2000-07-01

    Neurocalcin (NC) is a recently characterized EF-hand calcium-binding protein present in a discrete population of sensory neurons and their peripheral mechanoreceptors, but its presence in peripheral nervous system neurons other than in the rat is still unknown. The present study was designed to investigate the occurrence of NC in the dorsal root ganglia (DRG) of several mammalian species (horse, buffalo, cow, sheep, pig, dog, and rat), including humans. DRG were fixed, embedded in paraffin, and processed for immunohistochemistry using a polyclonal antibody against NC. The size of the immunoreactive neurons was measured. In all species examined, NC immunoreactivity (IR) was restricted to neurons but the percentage, as well as the size of the immunoreactive neurons, varied among different species. As a rule, small neurons (diameter <20 microm) lack NC IR. In some species (pig, dog, buffalo, cow), only the largest neurons showed IR, whereas in others (sheep, horse, rat, and humans) they covered the entire range of neuron sizes. The pattern of immunostaining was cytoplasmic, although in some species (cow and buffalo), it formed a peripheral "ring." The present results demonstrate that mammalian DRG contain a subpopulation of NC-positive neurons, which varies from one species to another. Based on the neuron size, the possible function of the NC-containing neurons is discussed. PMID:10861367

  14. Hypertension impairs hippocampus-related adult neurogenesis, CA1 neuron dendritic arborization and long-term memory.

    PubMed

    Shih, Y-H; Tsai, S-F; Huang, S-H; Chiang, Y-T; Hughes, M W; Wu, S-Y; Lee, C-W; Yang, T-T; Kuo, Y-M

    2016-05-13

    Hypertension is associated with neurodegenerative diseases and cognitive impairment. Several studies using spontaneous hypertensive rats to study the effect of hypertension on memory performance and adult hippocampal neurogenesis have reached inconsistent conclusions. The contradictory findings may be related to the genetic variability of spontaneous hypertensive rats due to the conventional breeding practices. The objective of this study is to examine the effect of hypertension on hippocampal structure and function in isogenic mice. Hypertension was induced by the '2 kidneys, 1 clip' method (2K1C) which constricted one of the two renal arteries. The blood pressures of 2K1C mice were higher than the sham group on post-operation day 7 and remained high up to day 28. Mice with 2K1C-induced hypertension had impaired long-term, but not short-term, memory. Dendritic complexity of CA1 neurons and hippocampal neurogenesis were reduced by 2K1C-induced hypertension on post-operation day 28. Furthermore, 2K1C decreased the levels of hippocampal brain-derived neurotrophic factor, while blood vessel density and activation status of astrocytes and microglia were not affected. In conclusion, hypertension impairs hippocampus-associated long-term memory, dendritic arborization and neurogenesis, which may be caused by down-regulation of brain-derived neurotrophic factor signaling pathways. PMID:26921651

  15. Expressing Constitutively Active Rheb in Adult Neurons after a Complete Spinal Cord Injury Enhances Axonal Regeneration beyond a Chondroitinase-Treated Glial Scar

    PubMed Central

    Wu, Di; Klaw, Michelle C.; Connors, Theresa; Kholodilov, Nikolai; Burke, Robert E.

    2015-01-01

    After a spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to: (1) the presence of inhibitory molecules, e.g., chondroitin sulfate proteoglycans (CSPG), in the glial scar at the lesion; and (2) the diminished growth capacity of adult neurons. We sought to determine whether expressing a constitutively active form of the GTPase Rheb (caRheb) in adult neurons after a complete SCI in rats improves intrinsic growth potential to result in axon regeneration out of a growth-supportive peripheral nerve grafted (PNG) into the SCI cavity. We also hypothesized that treating the glial scar with chondroitinase ABC (ChABC), which digests CSPG, would further allow caRheb-transduced neurons to extend axons across the distal graft interface. We found that targeting this pathway at a clinically relevant post-SCI time point improves both sprouting and regeneration of axons. CaRheb increased the number of axons, but not the number of neurons, that projected into the PNG, indicative of augmented sprouting. We also saw that caRheb enhanced sprouting far rostral to the injury. CaRheb not only increased growth rostral and into the graft, it also resulted in significantly more regrowth of axons across a ChABC-treated scar into caudal spinal cord. CaRheb+ neurons had higher levels of growth-associated-43, suggestive of a newly identified mechanism for mTOR-mediated enhancement of regeneration. Thus, we demonstrate for the first time that simultaneously addressing intrinsic and scar-associated, extrinsic impediments to regeneration results in significant regrowth beyond an extremely challenging, complete SCI site. SIGNIFICANCE STATEMENT After spinal cord injury (SCI), CNS axons fail to regenerate, resulting in permanent deficits. This is due to the diminished growth capacity of adult neurons and the presence of inhibitory molecules in the scar at the lesion. We sought to simultaneously counter both of these obstacles to achieve more robust

  16. Selective depression of nociceptive responses of dorsal horn neurones by SNC 80 in a perfused hindquarter preparation of adult mouse.

    PubMed

    Cao, C Q; Hong, Y G; Dray, A; Perkins, M N

    2001-01-01

    -nociceptive dorsal horn neurones were not inhibited by SNC 80 at a dose of up to 10 microM (n=5). These data demonstrate that delta-opioid receptor modulate nociceptive, but not non-nociceptive, transmission in spinal dorsal horn neurones of the adult mouse. The potentiation of neuronal activity by HS 378 may reflect an autoregulatory role of the endogenous delta-opioid in nociceptive transmission in mouse. PMID:11731107

  17. Trading new neurons for status: Adult hippocampal neurogenesis in eusocial Damaraland mole-rats.

    PubMed

    Oosthuizen, M K; Amrein, I

    2016-06-01

    Diversity in social structures, from solitary to eusocial, is a prominent feature of subterranean African mole-rat species. Damaraland mole-rats are eusocial, they live in colonies that are characterized by a reproductive division of labor and a subdivision into castes based on physiology and behavior. Damaraland mole-rats are exceptionally long lived and reproductive animals show delayed aging compared to non-reproductive animals. In the present study, we described the hippocampal architecture and the rate of hippocampal neurogenesis of wild-derived, adult Damaraland mole-rats in relation to sex, relative age and social status or caste. Overall, Damaraland mole-rats were found to have a small hippocampus and low rates of neurogenesis. We found no correlation between neurogenesis and sex or relative age. Social status or caste was the most prominent modulator of neurogenesis. An inverse relationship between neurogenesis and social status was apparent, with queens displaying the lowest neurogenesis while the worker mole-rats had the most. As there is no natural progression from one caste to another, social status within a colony was relatively stable and is reflected in the level of neurogenesis. Our results correspond to those found in the naked mole-rat, and may reflect an evolutionary and environmentally conserved trait within social mole-rat species. PMID:26979050

  18. Effects of ethanol during adolescence on the number of neurons and glia in the medial prefrontal cortex and basolateral amygdala of adult male and female rats

    PubMed Central

    Koss, W.A.; Sadowski, R.N.; Sherrill, L.K.; Gulley, J.M.; Juraska, J.M.

    2012-01-01

    Human adolescents often consume alcohol in a binge-like manner at a time when changes are occurring within specific brain structures, such as the medial prefrontal cortex (mPFC) and the basolateral nucleus of the amygdala (BLN). In particular, neuron and glia number are changing in both of these areas in the rat between adolescence and adulthood (Markham et al., 2007; Rubinow and Juraska, 2009). The current study investigated the effects of ethanol exposure during adolescence on the number of neurons and glia in the adult mPFC and BLN in Long-Evans male and female rats. Saline or 3 g/kg ethanol was administered between postnatal days (P) 35–45 in a binge-like pattern, with 2 days of injections followed by 1 day without an injection. Stereological analyses of the ventral mPFC (prelimbic and infralimbic areas) and the BLN were performed on brains from rats at 100 days of age. Neuron and glia densities were assessed with the optical disector and then multiplied by the volume to calculate the total number of neurons and glia. In the adult mPFC, ethanol administration during adolescence resulted in a decreased number of glia in males, but not females, and had no effect on the number of neurons. Adolescent ethanol exposure had no effects on glia or neuron number in the BLN. These results suggest that glia cells in the prefrontal cortex are particularly sensitive to binge-like exposure to ethanol during adolescence in male rats only, potentially due to a decrease in proliferation in males or protective mechanisms in females. PMID:22627163

  19. Effects of ethanol during adolescence on the number of neurons and glia in the medial prefrontal cortex and basolateral amygdala of adult male and female rats.

    PubMed

    Koss, W A; Sadowski, R N; Sherrill, L K; Gulley, J M; Juraska, J M

    2012-07-23

    Human adolescents often consume alcohol in a binge-like manner at a time when changes are occurring within specific brain structures, such as the medial prefrontal cortex (mPFC) and the basolateral nucleus of the amygdala (BLN). In particular, the number of neurons and glia is changing in both of these areas in the rat between adolescence and adulthood (Markham et al., 2007; Rubinow and Juraska, 2009). The current study investigated the effects of ethanol exposure during adolescence on the number of neurons and glia in the adult mPFC and BLN in Long-Evans male and female rats. Saline or 3g/kg ethanol was administered between postnatal days (P) 35-45 in a binge-like pattern, with 2days of injections followed by 1 day without an injection. Stereological analyses of the ventral mPFC (prelimbic and infralimbic areas) and the BLN were performed on brains from rats at 100 days of age. Neuron and glia densities were assessed with the optical disector and then multiplied by the volume to calculate the total number of neurons and glia. In the adult mPFC, ethanol administration during adolescence resulted in a decreased number of glia in males, but not females, and had no effect on the number of neurons. Adolescent ethanol exposure had no effects on glia or neuron number in the BLN. These results suggest that glia cells in the prefrontal cortex are particularly sensitive to binge-like exposure to ethanol during adolescence in male rats only, potentially due to a decrease in proliferation in males or protective mechanisms in females. PMID:22627163

  20. Scorpion venom heat-resistant peptide (SVHRP) enhances neurogenesis and neurite outgrowth of immature neurons in adult mice by up-regulating brain-derived neurotrophic factor (BDNF).

    PubMed

    Wang, Tao; Wang, Shi-Wei; Zhang, Yue; Wu, Xue-Fei; Peng, Yan; Cao, Zhen; Ge, Bi-Ying; Wang, Xi; Wu, Qiong; Lin, Jin-Tao; Zhang, Wan-Qin; Li, Shao; Zhao, Jie

    2014-01-01

    Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Although scorpions and their venom have been used in Traditional Chinese Medicine (TCM) to treat chronic neurological disorders, the underlying mechanisms of these treatments remain unknown. We applied SVHRP in vitro and in vivo to understand its effects on the neurogenesis and maturation of adult immature neurons and explore associated molecular mechanisms. SVHRP administration increased the number of 5-bromo-2'-dexoxyuridine (BrdU)-positive cells, BrdU-positive/neuron-specific nuclear protein (NeuN)-positive neurons, and polysialylated-neural cell adhesion molecule (PSA-NCAM)-positive immature neurons in the subventricular zone (SVZ) and subgranular zone (SGZ) of hippocampus. Furthermore immature neurons incubated with SVHRP-pretreated astrocyte-conditioned medium exhibited significantly increased neurite length compared with those incubated with normal astrocyte-conditioned medium. This neurotrophic effect was further confirmed in vivo by detecting an increased average single area and whole area of immature neurons in the SGZ, SVZ and olfactory bulb (OB) in the adult mouse brain. In contrast to normal astrocyte-conditioned medium, higher concentrations of brain-derived neurotrophic factor (BDNF) but not nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) was detected in the conditioned medium of SVHRP-pretreated astrocytes, and blocking BDNF using anti-BDNF antibodies eliminated these SVHRP-dependent neurotrophic effects. In SVHRP treated mouse brain, more glial fibrillary acidic protein (GFAP)-positive cells were detected. Furthermore, immunohistochemistry revealed increased numbers of GFAP/BDNF double-positive cells, which agrees with the observed changes in the culture system. This paper describes novel effects of scorpion venom-originated peptide on the stem cells and suggests the potential therapeutic values of SVHRP

  1. Scorpion Venom Heat-Resistant Peptide (SVHRP) Enhances Neurogenesis and Neurite Outgrowth of Immature Neurons in Adult Mice by Up-Regulating Brain-Derived Neurotrophic Factor (BDNF)

    PubMed Central

    Zhang, Yue; Wu, Xue-Fei; Peng, Yan; Cao, Zhen; Ge, Bi-Ying; Wang, Xi; Wu, Qiong; Lin, Jin-Tao; Zhang, Wan-Qin; Li, Shao; Zhao, Jie

    2014-01-01

    Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Although scorpions and their venom have been used in Traditional Chinese Medicine (TCM) to treat chronic neurological disorders, the underlying mechanisms of these treatments remain unknown. We applied SVHRP in vitro and in vivo to understand its effects on the neurogenesis and maturation of adult immature neurons and explore associated molecular mechanisms. SVHRP administration increased the number of 5-bromo-2’-dexoxyuridine (BrdU)-positive cells, BrdU- positive/neuron-specific nuclear protein (NeuN)-positive neurons, and polysialylated-neural cell adhesion molecule (PSA-NCAM)-positive immature neurons in the subventricular zone (SVZ) and subgranular zone (SGZ) of hippocampus. Furthermore immature neurons incubated with SVHRP-pretreated astrocyte-conditioned medium exhibited significantly increased neurite length compared with those incubated with normal astrocyte-conditioned medium. This neurotrophic effect was further confirmed in vivo by detecting an increased average single area and whole area of immature neurons in the SGZ, SVZ and olfactory bulb (OB) in the adult mouse brain. In contrast to normal astrocyte-conditioned medium, higher concentrations of brain-derived neurotrophic factor (BDNF) but not nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) was detected in the conditioned medium of SVHRP-pretreated astrocytes, and blocking BDNF using anti-BDNF antibodies eliminated these SVHRP-dependent neurotrophic effects. In SVHRP treated mouse brain, more glial fibrillary acidic protein (GFAP)-positive cells were detected. Furthermore, immunohistochemistry revealed increased numbers of GFAP/BDNF double-positive cells, which agrees with the observed changes in the culture system. This paper describes novel effects of scorpion venom-originated peptide on the stem cells and suggests the potential therapeutic values of

  2. CCL2 Mediates Neuron-Macrophage Interactions to Drive Proregenerative Macrophage Activation Following Preconditioning Injury.

    PubMed

    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

    2015-12-01

    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. PMID:26631474

  3. An RNA binding protein promotes axonal integrity in peripheral neurons by destabilizing REST.

    PubMed

    Cargnin, Francesca; Nechiporuk, Tamilla; Müllendorff, Karin; Stumpo, Deborah J; Blackshear, Perry J; Ballas, Nurit; Mandel, Gail

    2014-12-10

    The RE1 Silencing Transcription Factor (REST) acts as a governor of the mature neuronal phenotype by repressing a large consortium of neuronal genes in non-neuronal cells. In the developing nervous system, REST is present in progenitors and downregulated at terminal differentiation to promote acquisition of mature neuronal phenotypes. Paradoxically, REST is still detected in some regions of the adult nervous system, but how REST levels are regulated, and whether REST can still repress neuronal genes, is not known. Here, we report that homeostatic levels of REST are maintained in mature peripheral neurons by a constitutive post-transcriptional mechanism. Specifically, using a three-hybrid genetic screen, we identify the RNA binding protein, ZFP36L2, associated previously only with female fertility and hematopoiesis, and show that it regulates REST mRNA stability. Dorsal root ganglia in Zfp36l2 knock-out mice, or wild-type ganglia expressing ZFP36L2 shRNA, show higher steady-state levels of Rest mRNA and protein, and extend thin and disintegrating axons. This phenotype is due, at least in part, to abnormally elevated REST levels in the ganglia because the axonal phenotype is attenuated by acute knockdown of REST in Zfp36l2 KO DRG explants. The higher REST levels result in lower levels of target genes, indicating that REST can still fine-tune gene expression through repression. Thus, REST levels are titrated in mature peripheral neurons, in part through a ZFP36L2-mediated post-transcriptional mechanism, with consequences for axonal integrity. PMID:25505318

  4. Specific Distribution of the Autophagic Protein GABARAPL1/GEC1 in the Developing and Adult Mouse Brain and Identification of Neuronal Populations Expressing GABARAPL1/GEC1

    PubMed Central

    Le Grand, Jaclyn Nicole; Bon, Karine; Fraichard, Annick; Zhang, Jianhua; Jouvenot, Michèle; Risold, Pierre-Yves; Boyer-Guittaut, Michaël; Delage-Mourroux, Régis

    2013-01-01

    Macroautophagy is a highly conserved cellular degradation process, regulated by autophagy-related (atg) factors, in which a double membrane autophagosome engulfs cytoplasmic components to target them for degradation. In yeast, the Atg8 protein is indispensable for autophagosome formation. In mammals, this is complicated by the presence of six Atg8 homologues grouped into the GABARAP and MAP1LC3 subfamilies. Although these proteins share a high similarity, their transcript expression, regulation and protein interactions differ, suggesting they may display individual properties and specific functions. GABARAPL1/GEC1 is a member of the GABARAP subfamily and its mRNA is the most highly expressed Atg8 homologue in the central nervous system. Consequently, we performed an in depth study of GABARAPL1 distribution in the developing and adult murine brain. Our results show that GABARAPL1 brain expression is visible as early as embryonic day 11 and progressively increases to a maximum level in the adult. Immunohistochemical staining was detected in both fibers and immature neurons in embryos but was restrained to neurons in adult tissue. By E17, intense punctate-like structures were visible and these accumulated in cortical primary neurons treated with the autophagosome/lysosome fusion inhibitor Bafilomycin A1 (Baf A1), suggesting that they represent autophagosomes. Finally, GABARAPL1 expression was particularly intense in motoneurons in the embryo and in neurons involved in somatomotor and neuroendocrine functions in the adult, particularly in the substantia nigra pars compacta, a region affected in Parkinson's disease. Our study of cerebral GABARAPL1 protein expression provides insight into its role in the development and homeostasis of the mouse brain. PMID:23690988

  5. Inflammatory mediator bradykinin increases population of sensory neurons expressing functional T-type Ca(2+) channels.

    PubMed

    Huang, Dongyang; Liang, Ce; Zhang, Fan; Men, Hongchao; Du, Xiaona; Gamper, Nikita; Zhang, Hailin

    2016-04-29

    T-type Ca(2+) channels are important regulators of peripheral sensory neuron excitability. Accordingly, T-type Ca(2+) currents are often increased in various pathological pain conditions, such as inflammation or nerve injury. Here we investigated effects of inflammation on functional expression of T-type Ca(2+) channels in small-diameter cultured dorsal root ganglion (DRG) neurons. We found that overnight treatment of DRG cultures with a cocktail of inflammatory mediators bradykinin (BK), adenosine triphosphate (ATP), norepinephrine (NE) and prostaglandin E2 (PGE2) strongly increased the population size of the small-diameter neurons displaying low-voltage activated (LVA, T-type) Ca(2+) currents while having no effect on the peak LVA current amplitude. When applied individually, BK and ATP also increased the population size of LVA-positive neurons while NE and PGE2 had no effect. The PLC inhibitor U-73122 and B2 receptor antagonist, Hoe-140, both abolished the increase of the population of LVA-positive DRG neurons. Inflammatory treatment did not affect CaV3.2 mRNA or protein levels in DRG cultures. Furthermore, an ubiquitination inhibitor, MG132, did not increase the population of LVA-positive neurons. Our data suggest that inflammatory mediators BK and ATP increase the abundance of LVA-positive DRG neurons in total neuronal population by stimulating the recruitment of a 'reserve pool' of CaV3.2 channels, particularly in neurons that do not display measurable LVA currents under control conditions. PMID:26944020

  6. Inflammatory mediator bradykinin increases population of sensory neurons expressing functional T-type Ca2+ channels

    PubMed Central

    Huang, Dongyang; Liang, Ce; Zhang, Fan; Men, Hongchao; Du, Xiaona; Gamper, Nikita; Zhang, Hailin

    2016-01-01

    T-type Ca2+ channels are important regulators of peripheral sensory neuron excitability. Accordingly, T-type Ca2+ currents are often increased in various pathological pain conditions, such as inflammation or nerve injury. Here we investigated effects of inflammation on functional expression of T-type Ca2+ channels in small-diameter cultured dorsal root ganglion (DRG) neurons. We found that overnight treatment of DRG cultures with a cocktail of inflammatory mediators bradykinin (BK), adenosine triphosphate (ATP), norepinephrine (NE) and prostaglandin E2 (PGE2) strongly increased the population size of the small-diameter neurons displaying low-voltage activated (LVA, T-type) Ca2+ currents while having no effect on the peak LVA current amplitude. When applied individually, BK and ATP also increased the population size of LVA-positive neurons while NE and PGE2 had no effect. The PLC inhibitor U-73122 and B2 receptor antagonist, Hoe-140, both abolished the increase of the population of LVA-positive DRG neurons. Inflammatory treatment did not affect CaV3.2 mRNA or protein levels in DRG cultures. Furthermore, an ubiquitination inhibitor, MG132, did not increase the population of LVA-positive neurons. Our data suggest that inflammatory mediators BK and ATP increase the abundance of LVA-positive DRG neurons in total neuronal population by stimulating the recruitment of a ‘reserve pool’ of CaV3.2 channels, particularly in neurons that do not display measurable LVA currents under control conditions. PMID:26944020

  7. Intracellular calcium regulation among subpopulations of rat dorsal root ganglion neurons

    PubMed Central

    Lu, Shao-Gang; Zhang, Xiulin; Gold, Michael S

    2006-01-01

    Primary afferent neurons are functionally heterogeneous. To determine whether this functional heterogeneity reflects, in part, heterogeneity in the regulation of the concentration of intracellular Ca2+ ([Ca2+]i), the magnitude and decay of evoked Ca2+ transients were assessed in subpopulations of dorsal root ganglion (DRG) neurons with voltage clamp and fura-2 ratiometric imaging. To determine whether differences in evoked Ca2+ transients among subpopulations of DRG neurons reflected differences in the contribution of Ca2+ regulatory mechanisms, pharmacological techniques were employed to assess the contribution of influx, efflux, release and uptake pathways. Subpopulations of DRG neurons were defined by cell body size, binding of the plant lectin IB4 and responsiveness to the algogenic compound capsaicin (CAP). Ca2+ transients were evoked with 30 mm K+ or voltage steps to 0 mV. There were marked differences between subpopulations of neurons with respect to both the magnitude and decay of the Ca2+ transient, with the largest and most slowly decaying Ca2+ transients in small-diameter, IB4-positive, CAP-responsive neurons. The smallest and most rapidly decaying transients were in large-diameter, IB4-negative and CAP-unresponsive DRG neurons. These differences were not due to a differential distribution of voltage-gated Ca2+ currents. However, these differences did appear to reflect a differential contribution of other influx, efflux, release and uptake mechanisms between subpopulations of neurons. These results suggest that electrical activity in subpopulations of DRG neurons will have a differential influence on Ca2+-regulated phenomena such as spike adaptation, transmitter release and gene transcription. Significantly more activity should be required in large-diameter non-nociceptive afferents than in small-diameter nociceptive afferents to have a comparable influence on these processes. PMID:16945973

  8. Classification of neurons by dendritic branching pattern. A categorisation based on Golgi impregnation of spinal and cranial somatic and visceral afferent and efferent cells in the adult human.

    PubMed

    Abdel-Maguid, T E; Bowsher, D

    1984-06-01

    Neurons from adult human brainstem and spinal cord, fixed by immersion in formalin, were impregnated by a Golgi method and examined in sections 100 micron thick. Objective numerical criteria were used to classify completely impregnated neurons. Only the parameters mentioned below were found to be valid. Neurons in 100 micron sections were classified on the basis of (i) the primary dendrite number, indicated by a Roman numeral and called group; (ii) the dendritic branching pattern, comprising the highest branching order seen, indicated by an Arabic numeral and called category; the lowest dendritic branching order observed in complete neurons, indicated by an upper case letter and called class; and the number of branching orders seen between the two preceding, indicated by a lower case letter and called subclass. On the basis of the above characteristics, all neurons seen in the grey matter of the spinal cord and cranial nerve nuclei could be classified into thirteen 'families'. The results of other investigations (Abdel-Maguid & Bowsher, 1979, 1984) showed that this classification has functional value. PMID:6204961

  9. Effects of neuregulin-1 administration on neurogenesis in the adult mouse hippocampus, and characterization of immature neurons along the septotemporal axis.

    PubMed

    Mahar, Ian; MacIsaac, Angus; Kim, John Junghan; Qiang, Calvin; Davoli, Maria Antonietta; Turecki, Gustavo; Mechawar, Naguib

    2016-01-01

    Adult hippocampal neurogenesis is associated with learning and affective behavioural regulation. Its diverse functionality is segregated along the septotemporal axis from the dorsal to ventral hippocampus. However, features distinguishing immature neurons in these regions have yet to be characterized. Additionally, although we have shown that administration of the neurotrophic factor neuregulin-1 (NRG1) selectively increases proliferation and overall neurogenesis in the mouse ventral dentate gyrus (DG), likely through ErbB3, NRG1's effects on intermediate neurogenic stages in immature neurons are unknown. We examined whether NRG1 administration increases DG ErbB3 phosphorylation. We labeled adultborn cells using BrdU, then administered NRG1 to examine in vivo neurogenic effects on immature neurons with respect to cell survival, morphology, and synaptogenesis. We also characterized features of immature neurons along the septotemporal axis. We found that neurogenic effects of NRG1 are temporally and subregionally specific to proliferation in the ventral DG. Particular morphological features differentiate immature neurons in the dorsal and ventral DG, and cytogenesis differed between these regions. Finally, we identified synaptic heterogeneity surrounding the granule cell layer. These results indicate neurogenic involvement of NRG1-induced antidepressant-like behaviour is particularly associated with increased ventral DG cell proliferation, and identify novel distinctions between dorsal and ventral hippocampal neurogenic development. PMID:27469430

  10. Effects of neuregulin-1 administration on neurogenesis in the adult mouse hippocampus, and characterization of immature neurons along the septotemporal axis

    PubMed Central

    Mahar, Ian; MacIsaac, Angus; Kim, John Junghan; Qiang, Calvin; Davoli, Maria Antonietta; Turecki, Gustavo; Mechawar, Naguib

    2016-01-01

    Adult hippocampal neurogenesis is associated with learning and affective behavioural regulation. Its diverse functionality is segregated along the septotemporal axis from the dorsal to ventral hippocampus. However, features distinguishing immature neurons in these regions have yet to be characterized. Additionally, although we have shown that administration of the neurotrophic factor neuregulin-1 (NRG1) selectively increases proliferation and overall neurogenesis in the mouse ventral dentate gyrus (DG), likely through ErbB3, NRG1’s effects on intermediate neurogenic stages in immature neurons are unknown. We examined whether NRG1 administration increases DG ErbB3 phosphorylation. We labeled adultborn cells using BrdU, then administered NRG1 to examine in vivo neurogenic effects on immature neurons with respect to cell survival, morphology, and synaptogenesis. We also characterized features of immature neurons along the septotemporal axis. We found that neurogenic effects of NRG1 are temporally and subregionally specific to proliferation in the ventral DG. Particular morphological features differentiate immature neurons in the dorsal and ventral DG, and cytogenesis differed between these regions. Finally, we identified synaptic heterogeneity surrounding the granule cell layer. These results indicate neurogenic involvement of NRG1-induced antidepressant-like behaviour is particularly associated with increased ventral DG cell proliferation, and identify novel distinctions between dorsal and ventral hippocampal neurogenic development. PMID:27469430

  11. Policy trends and reforms in the German DRG-based hospital payment system.

    PubMed

    Klein-Hitpaß, Uwe; Scheller-Kreinsen, David

    2015-03-01

    A central structural point in all DRG-based hospital payment systems is the conversion of relative weights into actual payments. In this context policy makers need to address (amongst other things) (a) how the price level of DRG-payments from one period to the following period is changed and (b) whether and how hospital payments based on DRGs are to be differentiated beyond patient characteristics, e.g. by organizational, regional or state-level factors. Both policy problems can be and in international comparison often are empirically addressed. In Germany relative weights are derived from a highly sophisticated empirical cost calculation, whereas the annual changes of DRG-based payments (base rates) as well as the differentiation of DRG-based hospital payments beyond patient characteristics are not empirically addressed. Rather a complex set of regulations and quasi-market negotiations are applied. There were over the last decade also timid attempts to foster the use of empirical data to address these points. However, these reforms failed to increase the fairness, transparency and rationality of the mechanism to convert relative weights into actual DRG-based hospital payments. PMID:25638648

  12. Nesfatin-1 increases intracellular calcium concentration by protein kinase C activation in cultured rat dorsal root ganglion neurons.

    PubMed

    Ozcan, Mete; Gok, Zeynep Betul; Kacar, Emine; Serhatlioglu, Ihsan; Kelestimur, Haluk

    2016-04-21

    Nesfatin-1 is a recently identified anorexigenic hypothalamic polypeptide derived from the posttranslational processing of nucleobindin 2 (NUCB2). Several studies have indicated that this neuropeptide may be participated in somatosensory and visceral transmission including pain signals in addition to energy metabolism. The aim of this study was to explore the possible role of nesfatin-1 in the transmission of peripheral neural signals by investigating the effects of nesfatin-1 on intracellular free calcium levels ([Ca(2+)]i) in cultured neonatal rat dorsal root ganglion (DRG) neurons. The effects of nesfatin-1 on [Ca(2+)]i in DRG neurons were investigated by using an in vitro calcium imaging system. DRG neurons were grown in primary culture following enzymatic and mechanical dissociation of ganglia from 1-or 2-day-old neonatal Wistar rats. Using the fura-2-based calcium imaging technique, the effects of nesfatin-1 on [Ca(2+)]i and role of the protein kinase C (PKC)-mediated pathway in nesfatin-1 effect were assessed. Nesfatin-1 elevated [Ca(2+)]i in cultured DRG neurons. The response was prevented by pretreating the cells with pertussis toxin. The protein kinase C inhibitor chelerythrine chloride suppressed nesfatin-1-induced rise in [Ca(2+)]i. The result shows that nesfatin-1 interacts with a G protein-coupled receptor, leading to an increase of [Ca(2+)]i, which is linked to protein kinase C activation in cultured rat DRG neurons. PMID:26975784

  13. Neurons expressing individual enzymes of dopamine synthesis in the mediobasal hypothalamus of adult rats: functional significance and topographic interrelations.

    PubMed

    Ugrumov, M; Taxi, J; Pronina, T; Kurina, A; Sorokin, A; Sapronova, A; Calas, A

    2014-09-26

    Besides dopaminergic (DA-ergic) neurons having all enzymes of DA synthesis, tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase (AADC), "monoenzymatic" neurons expressing only one of them were found in the brain, mostly in the mediobasal hypothalamus (MBH). The aim of this study was to test our hypothesis that DA is synthesized by monoenzymatic neurons, i.e. l-3,4-dihydroxyphenylalanine (l-DOPA), which produced in the monoenzymatic TH neurons is transported in the monoenzymatic AADC neurons for DA synthesis. Incubation of MBH in Krebs-Ringer solution with l-leucine, a competitive inhibitor of l-DOPA uptake, was used to prevent a hypothetical l-DOPA capture into AADC-containing neurons. Incubation of the substantia nigra containing DA-ergic neurons under the same conditions served as the control. According to our data, the l-leucine administration provoked a decrease of DA concentration in MBH and in the incubation medium but not in the substantia nigra and respective incubation medium, showing a decrease of cooperative synthesis of DA in MBH. This conclusion was supported by an observation of higher concentration of l-DOPA in the incubation medium under perfusion of MBH with Krebs-Ringer solution containing tolcapone, an inhibitor of catechol-O-methyltransferase, and l-leucine than under perfusion with the same solution, but without l-leucine. Functional interaction between monoenzymatic TH and AADC neurons was indirectly confirmed by finding in electron microscopy their close relations in MBH. Besides monoenzymatic AADC neurons, any AADC-possessing neurons, catecholaminergic and serotoninergic, apparently, could participate in DA synthesis together with monoenzymatic TH neurons. This idea was confirmed by the observation of close topographic relations between monoenzymatic TH neurons and those containing both enzymes, i.e. DA-ergic, noradrenergic or adrenergic. Thus, monoenzymatic neurons possessing TH or AADC and being in close topographic relations

  14. Blocking miRNA Biogenesis in Adult Forebrain Neurons Enhances Seizure Susceptibility, Fear Memory, and Food Intake by Increasing Neuronal Responsiveness.

    PubMed

    Fiorenza, Anna; Lopez-Atalaya, Jose P; Rovira, Victor; Scandaglia, Marilyn; Geijo-Barrientos, Emilio; Barco, Angel

    2016-04-01

    The RNase Dicer is essential for the maturation of most microRNAs, a molecular system that plays an essential role in fine-tuning gene expression. To gain molecular insight into the role of Dicer and the microRNA system in brain function, we conducted 2 complementary RNA-seq screens in the hippocampus of inducible forebrain-restricted Dicer1 mutants aimed at identifying the microRNAs primarily affected by Dicer loss and their targets, respectively. Functional genomics analyses predicted the main biological processes and phenotypes associated with impaired microRNA maturation, including categories related to microRNA biology, signal transduction, seizures, and synaptic transmission and plasticity. Consistent with these predictions, we found that, soon after recombination, Dicer-deficient mice exhibited an exaggerated seizure response, enhanced induction of immediate early genes in response to different stimuli, stronger and more stable fear memory, hyperphagia, and increased excitability of CA1 pyramidal neurons. In the long term, we also observed slow and progressive excitotoxic neurodegeneration. Overall, our results indicate that interfering with microRNA biogenesis causes an increase in neuronal responsiveness and disrupts homeostatic mechanisms that protect the neuron against overactivation, which may explain both the initial and late phenotypes associated with the loss of Dicer in excitatory neurons. PMID:25595182

  15. Decreased voltage-gated potassium currents in rat dorsal root ganglion neurons after chronic constriction injury.

    PubMed

    Xiao, Yun; Wu, Yang; Zhao, Bo; Xia, Zhongyuan

    2016-01-20

    Voltage-gated potassium channels (KV) regulate pain transmission by controlling neuronal excitability. Changes in KV expression patterns may thus contribute toward hyperalgesia following nerve injury. The aim of this study was to characterize KV current density in dorsal root ganglion (DRG) neurons following chronic constriction injury (CCI) of the right sciatic nerve, a robust model of post-traumatic neuropathic pain. The study examined changes in small-diameter potassium ion currents (<30 µm) in neurons in the L4-L6 DRG following CCI by whole-cell patch-clamping and the association with post-CCI mechanical and thermal nociceptive thresholds. Compared with the control group, 7 days after CCI, the mechanical force and temperature required to elicit ipsilateral foot withdrawal decreased significantly, indicating tactile allodynia and thermal hyperalgesia. Post-CCI neurons had a significantly lower rheobase current and depolarized resting membrane potential than controls, suggesting KV current downregulation. Some ipsilateral DRG neurons also had spontaneous action potentials and repetitive firing. There was a 55% reduction in the total KV current density caused by a 55% decrease in the sustained delayed rectifier potassium ion current (IK) density and a 17% decrease in the transient A-type potassium ion current (IA) density. These results indicated that changes in DRG neuron IK and IA current density and concomitant afferent hyperexcitability may contribute toward neuropathic pain following injury. The rat CCI model may prove valuable for examining pathogenic mechanisms and potential therapies, such as KV channel modulators. PMID:26671526

  16. Morphology, Distribution and Phenotype of Polycystin Kidney Disease 2-like 1-Positive Cerebrospinal Fluid Contacting Neurons in The Brainstem of Adult Mice

    PubMed Central

    Orts-Del’Immagine, Adeline; Kastner, Anne; Tillement, Vanessa; Tardivel, Catherine; Trouslard, Jérôme; Wanaverbecq, Nicolas

    2014-01-01

    The mammalian spinal cord and medulla oblongata harbor unique neurons that remain in contact with the cerebrospinal fluid (CSF-cNs). These neurons were shown recently to express a polycystin member of the TRP channels family (PKD2L1) that potentially acts as a chemo- or mechanoreceptor. Recent studies carried out in young rodents indicate that spinal CSF-cNs express immature neuronal markers that appear to persist even in adult cells. Nevertheless, little is known about the phenotype and morphological properties of medullar CSF-cNs. Using immunohistochemistry and confocal microscopy techniques on tissues obtained from three-month old PKD2L1:EGFP transgenic mice, we analyzed the morphology, distribution, localization and phenotype of PKD2L1+ CSF-cNs around the brainstem and cervical spinal cord central canal. We show that PKD2L1+ CSF-cNs are GABAergic neurons with a subependymal localization, projecting a dendrite towards the central canal and an axon-like process running through the parenchyma. These neurons display a primary cilium on the soma and the dendritic process appears to bear ciliary-like structures in contact with the CSF. PKD2L1+ CSF-cNs present a conserved morphology along the length of the medullospinal central canal with a change in their density, localization and dendritic length according to the rostro-caudal axis. At adult stages, PKD2L1+ medullar CSF-cNs appear to remain in an intermediate state of maturation since they still exhibit characteristics of neuronal immaturity (DCX positive, neurofilament 160 kDa negative) along with the expression of a marker representative of neuronal maturation (NeuN). In addition, PKD2L1+ CSF-cNs express Nkx6.1, a homeodomain protein that enables the differentiation of ventral progenitors into somatic motoneurons and interneurons. The present study provides valuable information on the cellular properties of this peculiar neuronal population that will be crucial for understanding the physiological role of CSF

  17. [Extent and use of administrative hospital data in the German DRG system].

    PubMed

    Müller-Bergfort, S; Fritze, J

    2007-08-01

    In 2003 the mandatory introduction of diagnosis related groups as an overall payment system started for all hospitals in Germany, except for departments of psychiatry and psychotherapy as well as psychosomatics and psychotherapy. All hospitals are legally obliged to deliver extensive data on hospital treatment, including demographic data, diagnoses, comorbidities, complications, and procedures, to the "Institute for the Hospital Remuneration System" which uses the data for yearly adaptation of the German DRG system (G-DRG). This article describes legal issues of data collection, parameters and content of hospital data. In principle, the data might additionally be used for epidemiological, quality and public health issues which is, however, not supported by federal law, as of this time (January 2007). Completion of hospital data by unique patient identifiers, extended legal possibilities of scientific use of the data and the combination of hospital data from the DRG system with the data collected by the federal statistical office of Germany are proposed. PMID:17676420

  18. Ablation of neurons expressing melanin-concentrating hormone (MCH) in adult mice improves glucose tolerance independent of MCH signaling.

    PubMed

    Whiddon, Benjamin B; Palmiter, Richard D

    2013-01-30

    Melanin-concentrating hormone (MCH)-expressing neurons have been ascribed many roles based on studies of MCH-deficient mice. However, MCH neurons express other neurotransmitters, including GABA, nesfatin, and cocaine-amphetamine-regulated transcript. The importance of these other signaling molecules made by MCH neurons remains incompletely characterized. To determine the roles of MCH neurons in vivo, we targeted expression of the human diphtheria toxin receptor (DTR) to the gene for MCH (Pmch). Within 2 weeks of diphtheria toxin injection, heterozygous Pmch(DTR/+) mice lost 98% of their MCH neurons. These mice became lean but ate normally and were hyperactive, especially during a fast. They also responded abnormally to psychostimulants. For these phenotypes, ablation of MCH neurons recapitulated knock-out of MCH, so MCH appears to be the critical neuromodulator released by these neurons. In contrast, MCH-neuron-ablated mice showed improved glucose tolerance when compared with MCH-deficient mutant mice and wild-type mice. We conclude that MCH neurons regulate glucose tolerance through signaling molecules other than MCH. PMID:23365238

  19. Brain Insulin-Like Growth Factor-I Directs the Transition from Stem Cells to Mature Neurons During Postnatal/Adult Hippocampal Neurogenesis.

    PubMed

    Nieto-Estévez, Vanesa; Oueslati-Morales, Carlos O; Li, Lingling; Pickel, James; Morales, Aixa V; Vicario-Abejón, Carlos

    2016-08-01

    The specific actions of insulin-like growth factor-I (IGF-I) and the role of brain-derived IGF-I during hippocampal neurogenesis have not been fully defined. To address the influence of IGF-I on the stages of hippocampal neurogenesis, we studied a postnatal/adult global Igf-I knockout (KO) mice (Igf-I(-/-) ) and a nervous system Igf-I conditional KO (Igf-I(Δ/Δ) ). In both KO mice we found an accumulation of Tbr2(+) -intermediate neuronal progenitors, some of which were displaced in the outer granule cell layer (GCL) and the molecular layer (ML) of the dentate gyrus (DG). Similarly, more ectopic Ki67(+) - cycling cells were detected. Thus, the GCL was disorganized with significant numbers of Prox1(+) -granule neurons outside this layer and altered morphology of radial glial cells (RGCs). Dividing progenitors were also generated in greater numbers in clonal hippocampal stem cell (HPSC) cultures from the KO mice. Indeed, higher levels of Hes5 and Ngn2, transcription factors that maintain the stem and progenitor cell state, were expressed in both HPSCs and the GCL-ML from the Igf-I(Δ/Δ) mice. To determine the impact of Igf-I deletion on neuronal generation in vivo, progenitors in Igf-I(-/-) and Igf-I(+/+) mice were labeled with a GFP-expressing vector. This revealed that in the Igf-I(-/-) mice more GFP(+) -immature neurons were formed and they had less complex dendritic trees. These findings indicate that local IGF-I plays critical roles during postnatal/adult hippocampal neurogenesis, regulating the transition from HPSCs and progenitors to mature granule neurons in a cell stage-dependent manner. Stem Cells 2016;34:2194-2209. PMID:27144663

  20. Neurogenesis in the vomeronasal epithelium of adult garter snakes: 3. Use of /sup 3/H-thymidine autoradiography to trace the genesis and migration of bipolar neurons

    SciTech Connect

    Wang, R.T.; Halpern, M.

    1988-10-01

    Use of 3H-thymidine autoradiography and unilateral vomeronasal (VN) axotomy has permitted us to demonstrate directly the existence of VN stem cells in the adult garter snake and to trace continuous bipolar neuron development and migration in the normal VN and deafferentated VN epithelium in the same animal. The vomeronasal epithelium and olfactory epithelium of adult garter snakes are both capable of incorporating 3H-thymidine. In the sensory epithelium of the vomeronasal organ, 3H-thymidine-labeled cells were initially restricted to the base of the undifferentiated cell layer in animals surviving 1 day following 3H-thymidine injection. With increasing survival time, labeled cells progressively migrated vertically within the receptor cell column toward the apex of the bipolar neuron layer. In both the normal and denervated VN epithelium, labeled cells were observed through the 56 days of postoperative survival. In the normal epithelium, labeled cells were always located within the matrix of the intact receptor cell columns. However, labeled cells of the denervated epithelium were always located at the apical front of the newly formed cell mass following depletion of the original neuronal cell population. In addition, at postoperative days 28 and 56, labeled cells of the denervated VN epithelium achieved neuronal differentiation and maturation by migrating much farther away from the base of the receptor cell column than the labeled cells on the normal, unoperated contralateral side. This study directly demonstrates that basal cells initially incorporating 3H-thymidine are indeed stem cells of the VN epithelium in adult garter snakes.

  1. Green tea compound epigallo-catechin-3-gallate (EGCG) increases neuronal survival in adult hippocampal neurogenesis in vivo and in vitro.

    PubMed

    Ortiz-López, L; Márquez-Valadez, B; Gómez-Sánchez, A; Silva-Lucero, M D C; Torres-Pérez, M; Téllez-Ballesteros, R I; Ichwan, M; Meraz-Ríos, M A; Kempermann, G; Ramírez-Rodríguez, G B

    2016-05-13

    Epigallo-catechin-3-gallate (EGCG), found in the leaves of Camellia sinensis (green tea), has antioxidant- and scavenger-functions and acts neuroprotectively. It has been publicized as anti-aging remedy but data on potential cellular mechanisms are scarce. Recent studies claimed that EGCG specifically promotes neural precursor cell proliferation in the dentate gyrus of C57Bl/6 mice, without changes at the level of immature and mature new neurons. We here analyzed the effects of EGCG on adult hippocampal neurogenesis in male Balb/C mice and saw a different pattern. Two weeks of treatment with EGCG (0, 0.625, 1.25, 2.5, 5 and 10mg/kg) showed a dose-response curve that peaked at 2.5mg/kg of EGCG with significantly increased cell survival without affecting cell proliferation but decreasing apoptotic cells. Also, EGCG increased the population of doublecortin-(DCX)-expressing cells that comprises the late intermediate progenitor cells (type-2b and -3) as well as immature neurons. After EGCG treatment, the young DCX-positive neurons showed more elaborated dendritic trees. EGCG also significantly increased net neurogenesis in the adult hippocampus and increased the hippocampal levels of phospho-Akt. Ex vivo, EGCG exerted a direct effect on survival and neuronal differentiation of adult hippocampal precursor cells, which was absent, when PI3K, a protein upstream of Akt, was blocked. Our results thus support a pro-survival and a pro-neurogenic role of EGCG. In the context of the conflicting published results, however, potential genetic modifiers must be assumed. These might help to explain the overall variability of study results with EGCG. Our data do indicate, however, that natural compounds such as EGCG can in principle modulate brain plasticity. PMID:26917271

  2. Regulation of Piezo2 Mechanotransduction by Static Plasma Membrane Tension in Primary Afferent Neurons.

    PubMed

    Jia, Zhanfeng; Ikeda, Ryo; Ling, Jennifer; Viatchenko-Karpinski, Viacheslav; Gu, Jianguo G

    2016-04-22

    The Piezo2 channel is a newly identified mammalian mechanical transducer that confers rapidly adapting mechanically activated (RA-MA) currents in primary afferent neurons. The Piezo2 channels sense rapid membrane displacement, but it is not clear whether they are sensitive to osmotic swelling, which slowly increases static plasma membrane tension (SPMT). Here, we show that SPMT exerts a profound impact on the mechanical sensitivity of RA-MA channels in primary afferent neurons. RA-MA currents are greatly enhanced, and the mechanical threshold was reduced in both primary afferent neurons of rat dorsal root ganglia (DRG) and HEK293 cells heterologously expressing Piezo2 when these cells undergo osmotic swelling to increase SPMT. Osmotic swelling switches the kinetics of RA-MA currents to the slowly adapting type in both cultured DRG neurons and HEK293 cells heterologously expressing Piezo2. The potentiation of RA-MA currents is abolished when cultured DRG neurons are treated with cytochalasin D, an actin filament disruptor that prevents SPMT of cultured DRG neurons from an increase by osmotic swelling. Osmotic swelling significantly increases DRG neuron mechano-excitability such that a subthreshold mechanical stimulus can result in action potential firing. Behaviorally, the mechanical hind paw withdrawal threshold in rats is reduced following the injection of a hypotonic solution, but this osmotic effect is abolished when cytochalasin D or Gd(3+) is co-administered with the hypo-osmotic solution. Taken together, our findings suggest that Piezo2-mediated mechanotransduction is regulated by SPMT in primary afferent neurons. Because SPMT can be changed by multiple biological factors, our findings may have broad implications in mechanical sensitivity under physiological and pathological conditions. PMID:26929410

  3. Estimates of costs by DRG in Sydney teaching hospitals: an application of the Yale cost model.

    PubMed

    Palmer, G; Aisbett, C; Fetter, R; Winchester, L; Reid, B; Rigby, E

    1991-01-01

    The results are reported of a first round of costing by DRG in seven major teaching hospital sites in Sydney using the Yale cost model. These results, when compared between the hospitals and with values of relative costs by DRG from the United States, indicate that the cost modelling procedure has produced credible and potentially useful estimates of casemix costs. The rationale and underlying theory of cost modelling is explained, and the need for further work to improve the method of allocating costs to DRGs, and to improve the cost centre definitions currently used by the hospitals, is emphasised. PMID:10117339

  4. Surgical extraction of human dorsal root ganglia from organ donors and preparation of primary sensory neuron cultures.

    PubMed

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

    2016-10-01

    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. PMID:27606776

  5. Ca2+ waves in keratinocytes are transmitted to sensory neurons: the involvement of extracellular ATP and P2Y2 receptor activation.

    PubMed Central

    Koizumi, Schuichi; Fujishita, Kayoko; Inoue, Kaori; Shigemoto-Mogami, Yukari; Tsuda, Makoto; Inoue, Kazuhide

    2004-01-01

    ATP acts as an intercellular messenger in a variety of cells. In the present study, we have characterized the propagation of Ca2+ waves mediated by extracellular ATP in cultured NHEKs (normal human epidermal keratinocytes) that were co-cultured with mouse DRG (dorsal root ganglion) neurons. Pharmacological characterization showed that NHEKs express functional metabotropic P2Y2 receptors. When a cell was gently stimulated with a glass pipette, an increase in [Ca2+]i (intracellular Ca2+ concentration) was observed, followed by the induction of propagating Ca2+ waves in neighbouring cells in an extracellular ATP-dependent manner. Using an ATP-imaging technique, the release and diffusion of ATP in NHEKs were confirmed. DRG neurons are known to terminate in the basal layer of keratinocytes. In a co-culture of NHEKs and DRG neurons, mechanical-stimulation-evoked Ca2+ waves in NHEKs caused an increase in [Ca2+]i in the adjacent DRG neurons, which was also dependent on extracellular ATP and the activation of P2Y2 receptors. Taken together, extracellular ATP is a dominant messenger that forms intercellular Ca2+ waves in NHEKs. In addition, Ca2+ waves in NHEKs could cause an increase in [Ca2+]i in DRG neurons, suggesting a dynamic cross-talk between skin and sensory neurons mediated by extracellular ATP. PMID:14967069

  6. Lead induces similar gene expression changes in brains of gestationally exposed adult mice and in neurons differentiated from mouse embryonic stem cells.

    PubMed

    Sánchez-Martín, Francisco Javier; Fan, Yunxia; Lindquist, Diana M; Xia, Ying; Puga, Alvaro

    2013-01-01

    Exposure to environmental toxicants during embryonic life causes changes in the expression of developmental genes that may last for a lifetime and adversely affect the exposed individual. Developmental exposure to lead (Pb), an ubiquitous environmental contaminant, causes deficits in cognitive functions and IQ, behavioral effects, and attention deficit hyperactivity disorder (ADHD). Long-term effects observed after early life exposure to Pb include reduction of gray matter, alteration of myelin structure, and increment of criminal behavior in adults. Despite growing research interest, the molecular mechanisms responsible for the effects of lead in the central nervous system are still largely unknown. To study the molecular changes due to Pb exposure during neurodevelopment, we exposed mice to Pb in utero and examined the expression of neural markers, neurotrophins, transcription factors and glutamate-related genes in hippocampus, cortex, and thalamus at postnatal day 60. We found that hippocampus was the area where gene expression changes due to Pb exposure were more pronounced. To recapitulate gestational Pb exposure in vitro, we differentiated mouse embryonic stem cells (ESC) into neurons and treated ESC-derived neurons with Pb for the length of the differentiation process. These neurons expressed the characteristic neuronal markers Tubb3, Syp, Gap43, Hud, Ngn1, Vglut1 (a marker of glutamatergic neurons), and all the glutamate receptor subunits, but not the glial marker Gafp. Importantly, several of the changes observed in Pb-exposed mouse brains in vivo were also observed in Pb-treated ESC-derived neurons, including those affecting expression of Ngn1, Bdnf exon IV, Grin1, Grin2D, Grik5, Gria4, and Grm6. We conclude that our ESC-derived model of toxicant exposure during neural differentiation promises to be a useful model to analyze mechanisms of neurotoxicity induced by Pb and other environmental agents. PMID:24260418

  7. Lead Induces Similar Gene Expression Changes in Brains of Gestationally Exposed Adult Mice and in Neurons Differentiated from Mouse Embryonic Stem Cells

    PubMed Central

    Sánchez-Martín, Francisco Javier; Fan, Yunxia; Lindquist, Diana M.; Xia, Ying; Puga, Alvaro

    2013-01-01

    Exposure to environmental toxicants during embryonic life causes changes in the expression of developmental genes that may last for a lifetime and adversely affect the exposed individual. Developmental exposure to lead (Pb), an ubiquitous environmental contaminant, causes deficits in cognitive functions and IQ, behavioral effects, and attention deficit hyperactivity disorder (ADHD). Long-term effects observed after early life exposure to Pb include reduction of gray matter, alteration of myelin structure, and increment of criminal behavior in adults. Despite growing research interest, the molecular mechanisms responsible for the effects of lead in the central nervous system are still largely unknown. To study the molecular changes due to Pb exposure during neurodevelopment, we exposed mice to Pb in utero and examined the expression of neural markers, neurotrophins, transcription factors and glutamate-related genes in hippocampus, cortex, and thalamus at postnatal day 60. We found that hippocampus was the area where gene expression changes due to Pb exposure were more pronounced. To recapitulate gestational Pb exposure in vitro, we differentiated mouse embryonic stem cells (ESC) into neurons and treated ESC-derived neurons with Pb for the length of the differentiation process. These neurons expressed the characteristic neuronal markers Tubb3, Syp, Gap43, Hud, Ngn1, Vglut1 (a marker of glutamatergic neurons), and all the glutamate receptor subunits, but not the glial marker Gafp. Importantly, several of the changes observed in Pb-exposed mouse brains in vivo were also observed in Pb-treated ESC-derived neurons, including those affecting expression of Ngn1, Bdnf exon IV, Grin1, Grin2D, Grik5, Gria4, and Grm6. We conclude that our ESC-derived model of toxicant exposure during neural differentiation promises to be a useful model to analyze mechanisms of neurotoxicity induced by Pb and other environmental agents. PMID:24260418

  8. A highly enriched niche of precursor cells with neuronal and glial potential within the hair follicle dermal papilla of adult skin.

    PubMed

    Hunt, David P J; Morris, Paul N; Sterling, Jane; Anderson, Jane A; Joannides, Alexis; Jahoda, Colin; Compston, Alastair; Chandran, Siddharthan

    2008-01-01

    Skin-derived precursor cells (SKPs) are multipotent neural crest-related stem cells that grow as self-renewing spheres and are capable of generating neurons and myelinating glial cells. SKPs are of clinical interest because they are accessible and potentially autologous. However, although spheres can be readily isolated from embryonic and neonatal skin, SKP frequency falls away sharply in adulthood, and primary sphere generation from adult human skin is more problematic. In addition, the culture-initiating cell population is undefined and heterogeneous, limiting experimental studies addressing important aspects of these cells such as the behavior of endogenous precursors in vivo and the molecular mechanisms of neural generation. Using a combined fate-mapping and microdissection approach, we identified and characterized a highly enriched niche of neural crest-derived sphere-forming cells within the dermal papilla of the hair follicle of adult skin. We demonstrated that the dermal papilla of the rodent vibrissal follicle is 1,000-fold enriched for sphere-forming neural crest-derived cells compared with whole facial skin. These "papillaspheres" share a phenotypic and developmental profile similar to that of SKPs, can be readily expanded in vitro, and are able to generate both neuronal and glial cells in response to appropriate cues. We demonstrate that papillaspheres can be efficiently generated and expanded from adult human facial skin by microdissection of a single hair follicle. This strategy of targeting a highly enriched niche of sphere-forming cells provides a novel and efficient method for generating neuronal and glial cells from an accessible adult somatic source that is both defined and minimally invasive. PMID:17901404

  9. Neonatal Colon Insult Alters Growth Factor Expression and TRPA1 Responses in Adult Mice

    PubMed Central

    Christianson, Julie A.; Bielefeldt, Klaus; Malin, Sacha A.; Davis, Brian M.

    2010-01-01

    Inflammation or pain during neonatal development can result in long-term structural and functional alterations of nociceptive pathways, ultimately altering pain perception in adulthood. We have developed a mouse model of neonatal colon irritation (NCI) to investigate the plasticity of pain processing within the viscerosensory system. Mouse pups received an intracolonic administration of 2% mustard oil (MO) on postnatal days 8 and 10. Distal colons were processed at subsequent timepoints for myeloperoxidase (MPO) activity and growth factor expression. Adult mice were assessed for visceral hypersensitivity by measuring the visceromotor response during colorectal distension. Dorsal root ganglion (DRG) neurons from adult mice were retrogradely labeled from the distal colon and calcium imaging was used to measure transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) responses to acute application of capsaicin and MO, respectively. Despite the absence of inflammation (as indicated by MPO activity), neonatal exposure to intracolonic MO transiently maintained a higher expression level of growth factor messenger RNA (mRNA). Adult NCI mice displayed significant visceral hypersensitivity, as well as increased sensitivity to mechanical stimulation of the hindpaw, compared to control mice. The percentage of TRPA1-expressing colon afferents was significantly increased in NCI mice, however they displayed no increase in the percentage of TRPV1-immunopositive or capsaicin-sensitive colon DRG neurons. These results suggest that early neonatal colon injury results in a long-lasting visceral hypersensitivity, possibly driven by an early increase in growth factor expression and maintained by permanent changes in TRPA1 function. PMID:20850221

  10. Neonatal colon insult alters growth factor expression and TRPA1 responses in adult mice.

    PubMed

    Christianson, Julie A; Bielefeldt, Klaus; Malin, Sacha A; Davis, Brian M

    2010-11-01

    Inflammation or pain during neonatal development can result in long-term structural and functional alterations of nociceptive pathways, ultimately altering pain perception in adulthood. We have developed a mouse model of neonatal colon irritation (NCI) to investigate the plasticity of pain processing within the viscerosensory system. Mouse pups received an intracolonic administration of 2% mustard oil (MO) on postnatal days 8 and 10. Distal colons were processed at subsequent timepoints for myeloperoxidase (MPO) activity and growth factor expression. Adult mice were assessed for visceral hypersensitivity by measuring the visceromotor response during colorectal distension. Dorsal root ganglion (DRG) neurons from adult mice were retrogradely labeled from the distal colon and calcium imaging was used to measure transient receptor potential vanilloid 1 (TRPV1) and ankyrin 1 (TRPA1) responses to acute application of capsaicin and MO, respectively. Despite the absence of inflammation (as indicated by MPO activity), neonatal exposure to intracolonic MO transiently maintained a higher expression level of growth factor messenger RNA (mRNA). Adult NCI mice displayed significant visceral hypersensitivity, as well as increased sensitivity to mechanical stimulation of the hindpaw, compared to control mice. The percentage of TRPA1-expressing colon afferents was significantly increased in NCI mice, however they displayed no increase in the percentage of TRPV1-immunopositive or capsaicin-sensitive colon DRG neurons. These results suggest that early neonatal colon injury results in a long-lasting visceral hypersensitivity, possibly driven by an early increase in growth factor expression and maintained by permanent changes in TRPA1 function. PMID:20850221

  11. Distinct Developmental Origins Manifest in the Specialized Encoding of Movement by Adult Neurons of the External Globus Pallidus

    PubMed Central

    Dodson, Paul D.; Larvin, Joseph T.; Duffell, James M.; Garas, Farid N.; Doig, Natalie M.; Kessaris, Nicoletta; Duguid, Ian C.; Bogacz, Rafal; Butt, Simon J.B.; Magill, Peter J.

    2015-01-01

    Summary Transcriptional codes initiated during brain development are ultimately realized in adulthood as distinct cell types performing specialized roles in behavior. Focusing on the mouse external globus pallidus (GPe), we demonstrate that the potential contributions of two GABAergic GPe cell types to voluntary action are fated from early life to be distinct. Prototypic GPe neurons derive from the medial ganglionic eminence of the embryonic subpallium and express the transcription factor Nkx2-1. These neurons fire at high rates during alert rest, and encode movements through heterogeneous firing rate changes, with many neurons decreasing their activity. In contrast, arkypallidal GPe neurons originate from lateral/caudal ganglionic eminences, express the transcription factor FoxP2, fire at low rates during rest, and encode movements with robust increases in firing. We conclude that developmental diversity positions prototypic and arkypallidal neurons to fulfil distinct roles in behavior via their disparate regulation of GABA release onto different basal ganglia targets. PMID:25843402

  12. Molecular and functional expression of cation-chloride cotransporters in dorsal root ganglion neurons during postnatal maturation

    PubMed Central

    Mao, Shihong; Garzon-Muvdi, Tomás; Di Fulvio, Mauricio; Chen, Yanfang; Delpire, Eric; Alvarez, Francisco J.

    2012-01-01

    GABA depolarizes and excites central neurons during early development, becoming inhibitory and hyperpolarizing with maturation. This “developmental shift” occurs abruptly, reflecting a decrease in intracellular Cl− concentration ([Cl−]i) and a hyperpolarizing shift in Cl− equilibrium potential due to upregulation of the K+-Cl− cotransporter KCC2b, a neuron-specific Cl− extruder. In contrast, primary afferent neurons (PANs) are depolarized by GABA throughout adulthood because of expression of NKCC1, a Na+-K+-2Cl− cotransporter that accumulates Cl− above equilibrium. The GABAA-mediated depolarization of PANs determines presynaptic inhibition in the spinal cord, a key mechanism gating somatosensory information. Little is known about developmental changes in Cl− transporter expression and Cl− homeostasis in PANs. Whether NKCC1 is expressed in PANs of all phenotypes or is restricted to subpopulations (e.g., nociceptors) is debatable. Likewise, whether PANs express KCC2s is controversial. We investigated NKCC1 and K+-Cl− cotransporter expression in rat and mouse dorsal root ganglion (DRG) neurons with molecular methods. Using fluorescence imaging microscopy, we measured [Cl−]i in acutely dissociated rat DRG neurons (P0–P21) loaded with N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide and classified with phenotypic markers. DRG neurons of all sizes express two NKCC1 mRNAs, one full-length and a shorter splice variant lacking exon 21. Immunolabeling with validated antibodies revealed ubiquitous expression of NKCC1 in DRG neurons irrespective of postnatal age and phenotype. As maturation progresses [Cl−]i decreases gradually, persisting above equilibrium in >95% mature neurons. DRG neurons express mRNAs for KCC1, KCC3s, and KCC4, but not for KCC2s. Mechanisms underlying PANs' developmental changes in Cl− homeostasis are discussed and compared with those of central neurons. PMID:22457464

  13. Herpes simplex virus 1 tropism for human sensory ganglion neurons in the severe combined immunodeficiency mouse model of neuropathogenesis.

    PubMed

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

    2013-03-01

    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

  14. FIB/SEM technology and high-throughput 3D reconstruction of dendritic spines and synapses in GFP-labeled adult-generated neurons.

    PubMed

    Bosch, Carles; Martínez, Albert; Masachs, Nuria; Teixeira, Cátia M; Fernaud, Isabel; Ulloa, Fausto; Pérez-Martínez, Esther; Lois, Carlos; Comella, Joan X; DeFelipe, Javier; Merchán-Pérez, Angel; Soriano, Eduardo

    2015-01-01

    The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3-4 and 8-9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner. PMID:26052271

  15. FIB/SEM technology and high-throughput 3D reconstruction of dendritic spines and synapses in GFP-labeled adult-generated neurons

    PubMed Central

    Bosch, Carles; Martínez, Albert; Masachs, Nuria; Teixeira, Cátia M.; Fernaud, Isabel; Ulloa, Fausto; Pérez-Martínez, Esther; Lois, Carlos; Comella, Joan X.; DeFelipe, Javier; Merchán-Pérez, Angel; Soriano, Eduardo

    2015-01-01

    The fine analysis of synaptic contacts is usually performed using transmission electron microscopy (TEM) and its combination with neuronal labeling techniques. However, the complex 3D architecture of neuronal samples calls for their reconstruction from serial sections. Here we show that focused ion beam/scanning electron microscopy (FIB/SEM) allows efficient, complete, and automatic 3D reconstruction of identified dendrites, including their spines and synapses, from GFP/DAB-labeled neurons, with a resolution comparable to that of TEM. We applied this technology to analyze the synaptogenesis of labeled adult-generated granule cells (GCs) in mice. 3D reconstruction of dendritic spines in GCs aged 3–4 and 8–9 weeks revealed two different stages of dendritic spine development and unexpected features of synapse formation, including vacant and branched dendritic spines and presynaptic terminals establishing synapses with up to 10 dendritic spines. Given the reliability, efficiency, and high resolution of FIB/SEM technology and the wide use of DAB in conventional EM, we consider FIB/SEM fundamental for the detailed characterization of identified synaptic contacts in neurons in a high-throughput manner. PMID:26052271

  16. Exogenous brain-derived neurotrophic factor relieves pain symptoms of diabetic rats by reducing excitability of dorsal root ganglion neurons.

    PubMed

    Li, Lei; Yu, Ting; Yu, Liling; Li, Haijun; Liu, Yongjuan; Wang, Dongqin

    2016-08-01

    Diabetic peripheral neuropathy (DPN) is a common complication of diabetes lacking of effective treatments. Enhanced excitability of dorsal root ganglion (DRG) neuron plays a crucial role in the progression of diabetic neuropathic hyperalgesia. Brain-derived neurotrophic factor (BDNF) is known as a neuromodulator of nociception, but whether and how BDNF modulates the excitability of DRG neurons in the development of DPN remain to be clarified. This study investigated the role of exogenous BDNF and its high-affinity tropomyosin receptor kinase B (TrkB) in rats with streptozotocin-induced diabetic neuropathic pain. The results showed that continued intrathecal administration of BDNF to diabetic rats dramatically alleviated mechanical and thermal hyperalgesia, as well as inhibited hyperexcitability of DRG neurons. These effects were blocked by pretreatment with TrkB Fc (a synthetic fusion protein consisting of the extracellular ligand-binding domain of the TrkB receptor). The expression of BDNF and TrkB was upregulated in the DRG of diabetic rats. Intrathecal administration of BDNF did not affect this upregulation. These data provide novel information that exogenous BDNF relieved pain symptoms of diabetic rats by reducing hyperexcitability of DRG neurons and might be the potential treatment of painful diabetic neuropathy. PMID:26441011

  17. Cutaneous tissue damage induces long-lasting nociceptive sensitization and regulation of cellular stress- and nerve injury-associated genes in sensory neurons.

    PubMed

    Rau, Kristofer K; Hill, Caitlin E; Harrison, Benjamin J; Venkat, Gayathri; Koenig, Heidi M; Cook, Sarah B; Rabchevsky, Alexander G; Taylor, Bradley K; Hai, Tsonwin; Petruska, Jeffrey C

    2016-09-01

    Tissue damage is one of the major etiological factors in the emergence of chronic/persistent pain, although mechanisms remain enigmatic. Using incision of the back skin of adult rats as a model for tissue damage, we observed sensitization in a nociceptive reflex enduring to 28days post-incision (DPI). To determine if the enduring behavioral changes corresponded with a long-term impact of tissue damage on sensory neurons, we examined the temporal expression profile of injury-regulated genes and the electrophysiological properties of traced dorsal root ganglion (DRG) sensory neurons. The mRNA for the injury/stress-hub gene Activating Transcription Factor 3 (ATF3) was upregulated and peaked within 4 DPI, after which levels declined but remained significantly elevated out to 28 DPI, a time when the initial incision appears healed and tissue-inflammation largely resolved. Accordingly, stereological image analysis indicated that some neurons expressed ATF3 only transiently (mostly medium-large neurons), while in others it was sustained (mostly small neurons), suggesting cell-type-specific responses. In retrogradely-traced ATF3-expressing neurons, Calcium/calmodulin-dependent protein kinase type IV (CAMK4) protein levels and isolectin-B4 (IB4)-binding were suppressed whereas Growth Associated Protein-43 (GAP-43) and Neuropeptide Y (NPY) protein levels were enhanced. Electrophysiological recordings from DiI-traced sensory neurons 28 DPI showed a significant sensitization limited to ATF3-expressing neurons. Thus, ATF3 expression is revealed as a strong predictor of single cells displaying enduring pain-related electrophysiological properties. The cellular injury/stress response induced in sensory neurons by tissue damage and indicated by ATF3 expression is positioned to contribute to pain which can occur after tissue damage. PMID:27264359

  18. Modulating nitric oxide levels in dorsal root ganglion neurons of rat with low-level laser therapy

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

  19. Electrophysiological and Morphological Characteristics and Synaptic Connectivity of Tyrosine Hydroxylase-Expressing Neurons in Adult Mouse Striatum

    PubMed Central

    Ibáñez-Sandoval, Osvaldo; Tecuapetla, Fatuel; Unal, Bengi; Shah, Fulva; Koós, Tibor; Tepper, James M.

    2015-01-01

    Whole-cell recordings were obtained from tyrosine hydroxylase-expressing (TH+) neurons in striatal slices from bacterial artificial chromosome transgenic mice that synthesize enhanced green fluorescent protein (EGFP) selectively in neurons expressing TH transcriptional regulatory sequences. Stereological cell counting indicated that there were ~2700 EGFP–TH+ neurons/striatum. Whole-cell recordings in striatal slices demonstrated that EGFP–TH+ neurons comprise four electrophysiologically distinct neuron types whose electrophysiological properties have not been reported previously in striatum. EGFP–TH+ neurons were identified in retrograde tracing studies as interneurons. Recordings from synaptically connected pairs of EGFP–TH+ interneurons and spiny neurons showed that the interneurons elicited GABAergic IPSPs/IPSCs in spiny neurons powerful enough to significantly delay evoked spiking. EGFP–TH+ interneurons responded to local or cortical stimulation with glutamatergic EPSPs. Local stimulation also elicited GABAA IPSPs, at least some of which arose from identified spiny neurons. Single-cell reverse transcription-PCR showed expression of VMAT1 in EGFP–TH+ interneurons, consistent with previous suggestions that these interneurons may be dopaminergic as well as GABAergic. All four classes of interneurons were medium sized with modestly branching, varicose dendrites, and dense, highly varicose axon collateral fields. These data show for the first time that there exists in the normal rodent striatum a substantial population of TH+/GABAergic interneurons comprising four electrophysiologically distinct subtypes whose electrophysiological properties differ significantly from those of previously described striatal GABAergic interneurons. These interneurons are likely to play an important role in striatal function through fast GABAergic synaptic transmission in addition to, and independent of, their potential role in compensation for dopamine loss in experimental

  20. 42 CFR 412.517 - Revision of LTC-DRG group classifications and weighting factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Revision of LTC-DRG group classifications and weighting factors. 412.517 Section 412.517 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Prospective Payment System...

  1. 7.5-MINUTE DIGITAL RASTER GRAPHICS (DRG), VA PORTION OF ALBE

    EPA Science Inventory

    7.5-minute DRG for Virginia portion of Albemarle-Pamlico Estuary watershed. Files obtained from www.runet.edu:8800/~geoserve/Virginia.html at Radford University.
    Digital Raster Graphics (DRGs) come from the US Geological Survey in Universal Trans Mercator (UTM), North American...

  2. 42 CFR 476.84 - Changes as a result of DRG validation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Changes as a result of DRG validation. 476.84 Section 476.84 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) QUALITY IMPROVEMENT ORGANIZATIONS QUALITY IMPROVEMENT ORGANIZATION REVIEW Review Responsibilities of Quality...

  3. 42 CFR 476.84 - Changes as a result of DRG validation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 4 2013-10-01 2013-10-01 false Changes as a result of DRG validation. 476.84 Section 476.84 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) QUALITY IMPROVEMENT ORGANIZATIONS UTILIZATION AND QUALITY CONTROL REVIEW Review Responsibilities of Utilization and Quality...

  4. 42 CFR 476.84 - Changes as a result of DRG validation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 4 2012-10-01 2012-10-01 false Changes as a result of DRG validation. 476.84 Section 476.84 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) QUALITY IMPROVEMENT ORGANIZATIONS UTILIZATION AND QUALITY CONTROL REVIEW Review Responsibilities of Utilization and Quality...

  5. 42 CFR 412.517 - Revision of LTC-DRG group classifications and weighting factors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false Revision of LTC-DRG group classifications and weighting factors. 412.517 Section 412.517 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT...

  6. 42 CFR 412.517 - Revision of LTC-DRG group classifications and weighting factors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 2 2011-10-01 2011-10-01 false Revision of LTC-DRG group classifications and weighting factors. 412.517 Section 412.517 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT...

  7. 42 CFR 412.517 - Revision of LTC-DRG group classifications and weighting factors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 2 2013-10-01 2013-10-01 false Revision of LTC-DRG group classifications and weighting factors. 412.517 Section 412.517 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT...

  8. 42 CFR 412.517 - Revision of LTC-DRG group classifications and weighting factors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 2 2012-10-01 2012-10-01 false Revision of LTC-DRG group classifications and weighting factors. 412.517 Section 412.517 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT...

  9. [OR minute myth : Guidelines for calculation of DRG revenues per OR minute].

    PubMed

    Waeschle, R M; Hinz, J; Bleeker, F; Sliwa, B; Popov, A; Schmidt, C E; Bauer, M

    2016-02-01

    The economic situation in German Hospitals is tense and needs the implementation of differentiated controlling instruments. Accordingly, parameters of revenue development of different organizational units within a hospital are needed. This is particularly necessary in the revenue and cost-intensive operating theater field. So far there are only barely established productivity data for the control of operating room (OR) revenues during the year available. This article describes a valid method for the calculation of case-related revenues per OR minute conform to the diagnosis-related groups (DRG).For this purpose the relevant datasets from the OR information system and the § 21 productivity report (DRG grouping) of the University Medical Center Göttingen were combined. The revenues defined in the DRG browser of the Institute for Hospital Reimbursement (InEK) were assigned to the corresponding process times--incision-suture time (SNZ), operative preparation time and anesthesiology time--according to the InEK system. All full time stationary DRG cases treated within the OR were included and differentiated according to the surgical department responsible. The cost centers "OR section" and "anesthesia" were isolated to calculate the revenues of the operating theater. SNZ clusters and cost type groups were formed to demonstrate their impact on the revenues per OR minute. A surgical personal simultaneity factor (GZF) was calculated by division of the revenues for surgeons and anesthesiologists. This factor resembles the maximum DRG financed personnel deployment for surgeons in German hospitals.The revenue per OR minute including all cost types and DRG was 16.63 €/min. The revenues ranged from 10.45 to 24.34 €/min depending on the surgical field. The revenues were stable when SNZ clusters were analyzed. The differentiation of cost type groups revealed a revenue reduction especially after exclusion of revenues for implants and infrastructure. The calculated GZF over

  10. Voluntary exercise followed by chronic stress strikingly increases mature adult-born hippocampal neurons and prevents stress-induced deficits in 'what-when-where' memory.

    PubMed

    Castilla-Ortega, Estela; Rosell-Valle, Cristina; Pedraza, Carmen; Rodríguez de Fonseca, Fernando; Estivill-Torrús, Guillermo; Santín, Luis J

    2014-03-01

    We investigated whether voluntary exercise prevents the deleterious effects of chronic stress on episodic-like memory and adult hippocampal neurogenesis. After bromodeoxyuridine (BrdU) administration, mice were assigned to receive standard housing, chronic intermittent restraint stress, voluntary exercise or a combination of both (stress starting on the seventh day of exercise). Twenty-four days later, mice were tested in a 'what-when-where' object recognition memory task. Adult hippocampal neurogenesis (proliferation, differentiation, survival and apoptosis) and c-Fos expression in the hippocampus and extra-hippocampal areas (medial prefrontal cortex, amygdala, paraventricular hypothalamic nucleus, accumbens and perirhinal cortex) were assessed after behavior. Chronic intermittent restraint stress impaired neurogenesis and the 'when' memory, while exercise promoted neurogenesis and improved the 'where' memory. The 'when' and 'where' memories correlated with c-Fos expression in CA1 and the dentate gyrus, respectively. Furthermore, analysis suggested that each treatment induced a distinct pattern of functional connectivity among the areas analyzed for c-Fos. In the animals in which stress and exercise were combined, stress notably reduced the amount of voluntary exercise performed. Nevertheless, exercise still improved memory and counteracted the stress induced-deficits in neurogenesis and behavior. Interestingly, compared with the other three treatments, the stressed exercising animals showed a larger increase in cell survival, the maturation of new neurons and apoptosis in the dentate gyrus, with a considerable increase in the number of 24-day-old BrdU+cells that differentiated into mature neurons. The interaction between exercise and stress in enhancing the number of adult-born hippocampal neurons supports a role of exercise-induced neurogenesis in stressful conditions. PMID:24333647

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

    PubMed Central

    Kiniwa, Yukiko; Li, Jiang; Wang, Mingjun; Sun, Chuang; Lee, Jeffrey E.; Wang, Rong-Fu; Wang, Helen Y.

    2015-01-01

    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. PMID:25993655

  12. DRG-related prices applied in a public health care system--can Finland learn from Norway and Sweden?

    PubMed

    Mikkola, Hennamari; Keskimäki, Ilmo; Häkkinen, Unto

    2002-01-01

    In the early 1990s, DRG based hospital financing was introduced into some hospital districts in Finland. The 1993 state subsidy reform decentralising all hospital financing to municipalities, and the aim of improving productivity, were the driving forces for introducing DRG. This study addresses the pros and cons of DRG in hospital financing in the Finnish health care system and puts forward several solutions to avoid potential problems. We consider the objectives and optimal features of hospital financing systems in the context of the public health care system, where the public sector owns and finances hospitals. We analyse impacts of introducing different types of DRG based hospital financing systems, taking into account earlier experiences in countries such as Sweden and Norway, as well as Finnish system specific features. DRG could assist the Finnish municipalities to compare quality, costs and prices of services between hospitals, and related cost information might help them budget expenditure more accurately. System specific features mean that traditional uses of DRG in hospital pricing are not feasible in Finland. But some benefits of DRG could be exploited, for instance in the controlled contracts between municipalities and hospitals. PMID:11786173

  13. Prenatal Exposure to Autism-Specific Maternal Autoantibodies Alters Proliferation of Cortical Neural Precursor Cells, Enlarges Brain, and Increases Neuronal Size in Adult Animals.

    PubMed

    Martínez-Cerdeño, Verónica; Camacho, Jasmin; Fox, Elizabeth; Miller, Elaine; Ariza, Jeanelle; Kienzle, Devon; Plank, Kaela; Noctor, Stephen C; Van de Water, Judy

    2016-01-01

    Autism spectrum disorders (ASDs) affect up to 1 in 68 children. Autism-specific autoantibodies directed against fetal brain proteins have been found exclusively in a subpopulation of mothers whose children were diagnosed with ASD or maternal autoantibody-related autism. We tested the impact of autoantibodies on brain development in mice by transferring human antigen-specific IgG directly into the cerebral ventricles of embryonic mice during cortical neurogenesis. We show that autoantibodies recognize radial glial cells during development. We also show that prenatal exposure to autism-specific maternal autoantibodies increased stem cell proliferation in the subventricular zone (SVZ) of the embryonic neocortex, increased adult brain size and weight, and increased the size of adult cortical neurons. We propose that prenatal exposure to autism-specific maternal autoantibodies directly affects radial glial cell development and presents a viable pathologic mechanism for the maternal autoantibody-related prenatal ASD risk factor. PMID:25535268

  14. Glutaminase Increases in Rat Dorsal Root Ganglion Neurons after Unilateral Adjuvant-Induced Hind Paw Inflammation

    PubMed Central

    Hoffman, E. Matthew; Zhang, Zijia; Schechter, Ruben; Miller, Kenneth E.

    2016-01-01

    Glutamate is a neurotransmitter used at both the peripheral and central terminals of nociceptive primary sensory neurons, yet little is known concerning regulation of glutamate metabolism during peripheral inflammation. Glutaminase (GLS) is an enzyme of the glutamate-glutamine cycle that converts glutamine into glutamate for neurotransmission and is implicated in producing elevated levels of glutamate in central and peripheral terminals. A potential mechanism for increased levels of glutamate is an elevation in GLS expression. We assessed GLS expression after unilateral hind paw inflammation by measuring GLS immunoreactivity (ir) with quantitative image analysis of L4 dorsal root ganglion (DRG) neurons after one, two, four, and eight days of adjuvant-induced arthritis (AIA) compared to saline injected controls. No significant elevation in GLS-ir occurred in the DRG ipsilateral to the inflamed hind paw after one or two days of AIA. After four days AIA, GLS-ir was elevated significantly in all sizes of DRG neurons. After eight days AIA, GLS-ir remained elevated in small (<400 µm2), presumably nociceptive neurons. Western blot analysis of the L4 DRG at day four AIA confirmed the elevated GLS-ir. The present study indicates that GLS expression is increased in the chronic stage of inflammation and may be a target for chronic pain therapy. PMID:26771651

  15. ALS-linked TDP-43 mutations produce aberrant RNA splicing and adult-onset motor neuron disease without aggregation or loss of nuclear TDP-43.

    PubMed

    Arnold, Eveline S; Ling, Shuo-Chien; Huelga, Stephanie C; Lagier-Tourenne, Clotilde; Polymenidou, Magdalini; Ditsworth, Dara; Kordasiewicz, Holly B; McAlonis-Downes, Melissa; Platoshyn, Oleksandr; Parone, Philippe A; Da Cruz, Sandrine; Clutario, Kevin M; Swing, Debbie; Tessarollo, Lino; Marsala, Martin; Shaw, Christopher E; Yeo, Gene W; Cleveland, Don W

    2013-02-19

    Transactivating response region DNA binding protein (TDP-43) is the major protein component of ubiquitinated inclusions found in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) with ubiquitinated inclusions. Two ALS-causing mutants (TDP-43(Q331K) and TDP-43(M337V)), but not wild-type human TDP-43, are shown here to provoke age-dependent, mutant-dependent, progressive motor axon degeneration and motor neuron death when expressed in mice at levels and in a cell type-selective pattern similar to endogenous TDP-43. Mutant TDP-43-dependent degeneration of lower motor neurons occurs without: (i) loss of TDP-43 from the corresponding nuclei, (ii) accumulation of TDP-43 aggregates, and (iii) accumulation of insoluble TDP-43. Computational analysis using splicing-sensitive microarrays demonstrates alterations of endogenous TDP-43-dependent alternative splicing events conferred by both human wild-type and mutant TDP-43(Q331K), but with high levels of mutant TDP-43 preferentially enhancing exon exclusion of some target pre-mRNAs affecting genes involved in neurological transmission and function. Comparison with splicing alterations following TDP-43 depletion demonstrates that TDP-43(Q331K) enhances normal TDP-43 splicing function for some RNA targets but loss-of-function for others. Thus, adult-onset motor neuron disease does not require aggregation or loss of nuclear TDP-43, with ALS-linked mutants producing loss and gain of splicing function of selected RNA targets at an early disease stage. PMID:23382207

  16. Schwann Cell Expressed Nogo-B Modulates Axonal Branching of Adult Sensory Neurons Through the Nogo-B Receptor NgBR

    PubMed Central

    Eckharter, Christoph; Junker, Nina; Winter, Lilli; Fischer, Irmgard; Fogli, Barbara; Kistner, Steffen; Pfaller, Kristian; Zheng, Binhai; Wiche, Gerhard; Klimaschewski, Lars; Schweigreiter, Rüdiger

    2015-01-01

    In contrast to the central nervous system (CNS) nerve fibers do regenerate in the peripheral nervous system (PNS) although in a clinically unsatisfying manner. A major problem is excessive sprouting of regenerating axons which results in aberrant reinnervation of target tissue and impaired functional recovery. In the CNS, the reticulon protein Nogo-A has been identified as a prominent oligodendrocyte expressed inhibitor of long-distance growth of regenerating axons. We show here that the related isoform Nogo-B is abundantly expressed in Schwann cells in the PNS. Other than Nogo-A in oligodendrocytes, Nogo-B does not localize to the myelin sheath but is detected in the ER and the plasma membrane of Schwann cells. Adult sensory neurons that are cultured on nogo-a/b deficient Schwann cells form significantly fewer axonal branches vs. those on wildtype Schwann cells, while their maximal axonal extension is unaffected. We demonstrate that this effect of Nogo-B on neuronal morphology is restricted to undifferentiated Schwann cells and is mediated by direct physical contact between these two cell types. Moreover, we show that blocking the Nogo-B specific receptor NgBR, which we find expressed on sensory neurons and to interact with Schwann cell expressed Nogo-B, produces the same branching phenotype as observed after deletion of Nogo-B. These data provide evidence for a novel function of the nogo gene that is implemented by the Nogo-B isoform. The remarkably specific effects of Nogo-B/NgBR on axonal branching, while leaving axonal extension unaffected, are of potential clinical relevance in the context of excessive axonal sprouting after peripheral nerve injury. Main Points Nogo-B is prominently expressed in Schwann cells and localizes to the ER and plasma membrane. It distributes to the external cytoplasmic compartment of Schwann cells in vivo, but is absent from the myelin sheath. Genetic deletion of Nogo-B in Schwann cells reduces axonal branching, but not long

  17. Upregulated Expression of Karyopherin α2 is Involved in Neuronal Apoptosis Following Intracerebral Hemorrhage in Adult Rats.

    PubMed

    Xu, Zhiwei; Chen, Jianping; Shi, Jiansheng; Zhao, Jianmei; Wang, Jun; Ji, Yuhong; Han, Lijian; Zhu, Liang; Li, Xiaohong; Zhang, Dongmei

    2016-07-01

    Karyopherin α2 (KPNA2) plays a central role in nucleocytoplasmic transport. It is involved in controlling the flow of genetic information and the modulation of diverse cellular activities. Here we explored the KPNA2's roles during the pathophysiological processes of intracerebral hemorrhage (ICH). An ICH rat model was built and evaluated according to behavioral testing. Using Western blot, immunohistochemistry, and immunofluorescence, significant upregulation of KPNA2 was found in neurons in brain areas surrounding the hematoma following ICH. Increasing KPNA2 level was found to be accompanied by the upregulation of active caspase-3, Bax, and decreased expression of Bcl-2. Besides, KPNA2 co-localized well with active caspase-3 in neurons, indicating its potential role in neuronal apoptosis. What's more, knocking down KPNA2 by RNA-interference in PC12 cells reduced active caspase-3 expression. Thus, KPNA2 may play a role in promoting the brain secondary damage following ICH. PMID:26340948

  18. [Introduction of the DRG system from the point of view of private health insurers].

    PubMed

    Fritze, Jürgen; Miebach, Jürgen; Hüdig, Wolfgang

    2002-08-01

    For the first time, there has been a worldwide attempt to fund all hospital services almost completely by a DRG system supplemented by additional charges, rebates, and procedural rates. In the interest of the efficiency and transparency of hospital services the introduction of a German DRG system settling the current implausible price differences would be welcome. The system selected by the medical self-governing bodies in Germany is based upon the Australian AR-DRG classification. In contrast to other systems, the latter provides the best medical plausibility, the highest transparency of the assignment algorithm and the highest potential for flexibility and adaptations to changing morbidity patterns and medical progress. The adaptation to the conditions of the German health care system requires considerable efforts on the part of hospitals as well as sickness funds and health insurers. Hospitals need to establish a cost unit accounting system satisfying the rules of Applied Economics to allow, among other things, the calculation of relative cost weights. The self-governing bodies will have to consent on a complex regulation system. The German Hospital Federation declared the break down of negotiations concerning a provisional DRG system to be optionally available to hospitals in 2003. The Federal Ministry of Health will now have to decide whether to implement the system through executive fiat. The comprehensive DRG system will introduce new risks. The economic risks of the individual hospital, though not the individual insurer's risks, will be partially compensated for in the introductory phase by revenue balance mechanisms, for example. In particular, both the privately insured and civil servants will face a rise in costs as they will no longer benefit from a shorter length of hospital stay. To end this discrimination against private health insurers, the double counting of the costs associated with medical treatment (included in the DRG price and additionally

  19. Development of nNOS-positive neurons in the rat sensory ganglia after capsaicin treatment.

    PubMed

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

    2015-08-27

    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. PMID:26054303

  20. Osmotic Edema Rapidly Increases Neuronal Excitability Through Activation of NMDA Receptor-Dependent Slow Inward Currents in Juvenile and Adult Hippocampus.

    PubMed

    Lauderdale, Kelli; Murphy, Thomas; Tung, Tina; Davila, David; Binder, Devin K; Fiacco, Todd A

    2015-01-01

    Cellular edema (cell swelling) is a principal component of numerous brain disorders including ischemia, cortical spreading depression, hyponatremia, and epilepsy. Cellular edema increases seizure-like activity in vitro and in vivo, largely through nonsynaptic mechanisms attributable to reduction of the extracellular space. However, the types of excitability changes occurring in individual neurons during the acute phase of cell volume increase remain unclear. Using whole-cell patch clamp techniques, we report that one of the first effects of osmotic edema on excitability of CA1 pyramidal cells is the generation of slow inward currents (SICs), which initiate after approximately 1 min. Frequency of SICs increased as osmolarity decreased in a dose-dependent manner. Imaging of real-time volume changes in astrocytes revealed that neuronal SICs occurred while astrocytes were still in the process of swelling. SICs evoked by cell swelling were mainly nonsynaptic in origin and NMDA receptor-dependent. To better understand the relationship between SICs and changes in neuronal excitability, recordings were performed in increasingly physiological conditions. In the absence of any added pharmacological reagents or imposed voltage clamp, osmotic edema induced excitatory postsynaptic potentials and burst firing over the same timecourse as SICs. Like SICs, action potentials were blocked by NMDAR antagonists. Effects were more pronounced in adult (8-20 weeks old) compared with juvenile (P15-P21) mice. Together, our results indicate that cell swelling triggered by reduced osmolarity rapidly increases neuronal excitability through activation of NMDA receptors. Our findings have important implications for understanding nonsynaptic mechanisms of epilepsy in relation to cell swelling and reduction of the extracellular space. PMID:26489684

  1. High expression of cytochrome b 5 reductase isoform 3/cytochrome b 5 system in the cerebellum and pyramidal neurons of adult rat brain.

    PubMed

    Samhan-Arias, A K; López-Sánchez, C; Marques-da-Silva, D; Lagoa, R; Garcia-Lopez, V; García-Martínez, V; Gutierrez-Merino, C

    2016-05-01

    Cytochrome b 5 reductase (Cb 5R) and cytochrome b 5 (Cb 5) form an enzymatic redox system that plays many roles in mammalian cells. In the last 15 years, it has been proposed that this system is involved in the recycling of ascorbate, a vital antioxidant molecule in the brain and that its deregulation can lead to the production of reactive oxygen species that play a major role in oxidative-induced neuronal death. In this work, we have performed a regional and cellular distribution study of the expression of this redox system in adult rat brain by anti-Cb 5R isoform 3 and anti-Cb 5 antibodies. We found high expression levels in cerebellar cortex, labeling heavily granule neurons and Purkinje cells, and in structures such as the fastigial, interposed and dentate cerebellar nuclei. A large part of Cb 5R isoform 3 in the cerebellum cortex was regionalized in close proximity to the lipid raft-like nanodomains, labeled with cholera toxin B, as we have shown by fluorescence resonance energy transfer imaging. In addition, vestibular, reticular and motor nuclei located at the brain stem level and pyramidal neurons of somatomotor areas of the brain cortex and of the hippocampus have been also found to display high expression levels of these proteins. All these results point out the enrichment of Cb 5R isoform 3/Cb 5 system in neuronal cells and structures of the cerebellum and brain stem whose functional impairment can account for neurological deficits reported in type II congenital methemoglobinemia, as well as in brain areas highly prone to undergo oxidative stress-induced neurodegeneration. PMID:25850901

  2. Osmotic Edema Rapidly Increases Neuronal Excitability Through Activation of NMDA Receptor-Dependent Slow Inward Currents in Juvenile and Adult Hippocampus

    PubMed Central

    Lauderdale, Kelli; Murphy, Thomas; Tung, Tina; Davila, David; Binder, Devin K.

    2015-01-01

    Cellular edema (cell swelling) is a principal component of numerous brain disorders including ischemia, cortical spreading depression, hyponatremia, and epilepsy. Cellular edema increases seizure-like activity in vitro and in vivo, largely through nonsynaptic mechanisms attributable to reduction of the extracellular space. However, the types of excitability changes occurring in individual neurons during the acute phase of cell volume increase remain unclear. Using whole-cell patch clamp techniques, we report that one of the first effects of osmotic edema on excitability of CA1 pyramidal cells is the generation of slow inward currents (SICs), which initiate after approximately 1 min. Frequency of SICs increased as osmolarity decreased in a dose-dependent manner. Imaging of real-time volume changes in astrocytes revealed that neuronal SICs occurred while astrocytes were still in the process of swelling. SICs evoked by cell swelling were mainly nonsynaptic in origin and NMDA receptor-dependent. To better understand the relationship between SICs and changes in neuronal excitability, recordings were performed in increasingly physiological conditions. In the absence of any added pharmacological reagents or imposed voltage clamp, osmotic edema induced excitatory postsynaptic potentials and burst firing over the same timecourse as SICs. Like SICs, action potentials were blocked by NMDAR antagonists. Effects were more pronounced in adult (8–20 weeks old) compared with juvenile (P15–P21) mice. Together, our results indicate that cell swelling triggered by reduced osmolarity rapidly increases neuronal excitability through activation of NMDA receptors. Our findings have important implications for understanding nonsynaptic mechanisms of epilepsy in relation to cell swelling and reduction of the extracellular space. PMID:26489684

  3. 8-Oxoguanine accumulation in mitochondrial DNA causes mitochondrial dysfunction and impairs neuritogenesis in cultured adult mouse cortical neurons under oxidative conditions

    PubMed Central

    Leon, Julio; Sakumi, Kunihiko; Castillo, Erika; Sheng, Zijing; Oka, Sugako; Nakabeppu, Yusaku

    2016-01-01

    Oxidative stress and mitochondrial dysfunction are implicated in aging-related neurodegenerative disorders. 8-Oxoguanine (8-oxoG), a common oxidised base lesion, is often highly accumulated in brains from patients with neurodegenerative disorders. MTH1 hydrolyses 8-oxo-2′-deoxyguanosine triphosphate (8-oxo-dGTP) to 8-oxo-dGMP and pyrophosphate in nucleotide pools, while OGG1 excises 8-oxoG paired with cytosine in DNA, thereby minimising the accumulation of 8-oxoG in DNA. Mth1/Ogg1-double knockout (TO-DKO) mice are highly susceptible to neurodegeneration under oxidative conditions and show increased accumulation of 8-oxoG in mitochondrial DNA (mtDNA) in neurons, suggesting that 8-oxoG accumulation in mtDNA causes mitochondrial dysfunction. Here, we evaluated the contribution of MTH1 and OGG1 to the prevention of mitochondrial dysfunction during neuritogenesis in vitro. We isolated cortical neurons from adult wild-type and TO-DKO mice and maintained them with or without antioxidants for 2 to 5 days and then examined neuritogenesis. In the presence of antioxidants, both TO-DKO and wild-type neurons exhibited efficient neurite extension and arborisation. However, in the absence of antioxidants, the accumulation of 8-oxoG in mtDNA of TO-DKO neurons was increased resulting in mitochondrial dysfunction. Cells also exhibited poor neurite outgrowth with decreased complexity of neuritic arborisation, indicating that MTH1 and OGG1 are essential for neuritogenesis under oxidative conditions. PMID:26912170

  4. Multiple sodium channels and their roles in electrogenesis within dorsal root ganglion neurons

    PubMed Central

    Rush, Anthony M; Cummins, Theodore R; Waxman, Stephen G

    2007-01-01

    Dorsal root ganglion neurons express an array of sodium channel isoforms allowing precise control of excitability. An increasing body of literature indicates that regulation of firing behaviour in these cells is linked to their patterns of expression of specific sodium channel isoforms, which have been discovered to possess distinct biophysical characteristics. The pattern of expression of sodium channels differs in different subclasses of DRG neurons and is not fixed but, on the contrary, changes in response to a variety of disease insults. Moreover, modulation of channels by their environment has been found to play an important role in the response of these neurons to stimuli. In this review we illustrate how excitability can be finely tuned to provide contrasting firing templates in different subclasses of DRG neurons by selective deployment of various sodium channel isoforms, by plasticity of expression of these proteins, and by interactions of these sodium channel isoforms with each other and with other modulatory molecules. PMID:17158175

  5. Co-culture of osteocytes and neurons on a unique patterned surface

    PubMed Central

    Boggs, Mary E.; Thompson, William R.; Farach-Carson, Mary C.; Duncan, Randall L.; Beebe, Thomas P.

    2011-01-01

    Neural and skeletal communication is essential for the maintenance of bone mass and transmission of pain, yet the mechanism(s) of signal transduction between these tissues is unknown. The authors established a novel system to co-culture murine long bone osteocyte-like cells (MLO-Y4) and primary murine dorsal root ganglia (DRG) neurons. Assessment of morphology and maturation marker expression on perlecan domain IV peptide (PlnDIV) and collagen type-1 (Col1) demonstrated that PlnDIV was an optimal matrix for MLO-Y4 culture. A novel matrix-specificity competition assay was developed to expose these cells to several extracellular matrix proteins such as PlnDIV, Col1, and laminin (Ln). The competition assay showed that approximately 70% of MLOY4 cells preferred either PlnDIV or Col1 to Ln. To co-culture MLO-Y4 and DRG, we developed patterned surfaces using micro-contact printing to create 40 μm × 1 cm alternating stripes of PlnDIV and Ln or PlnDIV and Col1. Co-culture on PlnDIV/Ln surfaces demonstrated that these matrix molecules provided unique cues for each cell type, with MLO-Y4 preferentially attaching to the PlnDIV lanes and DRG neurons to the Ln lanes. Approximately 80% of DRG were localized to Ln. Cellular processes from MLO-Y4 were closely associated with axonal extensions of DRG neurons. Approximately 57% of neuronal processes were in close proximity to nearby MLO-Y4 cells at the PlnDIV-Ln interface. The surfaces in this new assay provided a unique model system with which to study the communication between osteocyte-like cells and neurons in an in vitro environment. PMID:22239813

  6. TRICARE revision to CHAMPUS DRG-based payment system, pricing of hospital claims. Final rule.

    PubMed

    2014-05-21

    This Final rule changes TRICARE's current regulatory provision for inpatient hospital claims priced under the DRG-based payment system. Claims are currently priced by using the rates and weights that are in effect on a beneficiary's date of admission. This Final rule changes that provision to price such claims by using the rates and weights that are in effect on a beneficiary's date of discharge. PMID:24851315

  7. [A DRG based future hospital funding scheme: state of implementation and impact in the field of rehabilitation].

    PubMed

    Rochell, B; Roeder, N

    2002-02-01

    With the statutory health insurance reform act 2000 the German government started to introduce a new hospital funding system based on an internationally used diagnosis related groups (DRGs) system. In June 2000 the German self-administration board (consisting of the German hospital federation, the German statutory health insurance funds and the association of private health insurers), which is in charge of realizing this project, decided to develop the future German (Refined) DRG System (G-DRG) with reference to the Australian Refined DRG System (AR-DRG) Version 4.1. Replacement of the previous German hospital reimbursement system by the new DRG-based hospital funding system is planned for January 2003 on a voluntary basis. From January 2004 on, the change of the reimbursement system is to become mandatory for all hospitals with the exception of psychiatry. The new reimbursement system is intended to not only cover acute hospital care but also parts of early rehabilitation, palliative and sub-acute care. Because of its economic incentives the effects of DRG introduction in Germany will not only be limited to the hospital scene but will also affect rehabilitation. PMID:11830787

  8. RNAi silencing of P/Q-type calcium channels in Purkinje neurons of adult mouse leads to episodic ataxia type 2.

    PubMed

    Salvi, Julie; Bertaso, Federica; Mausset-Bonnefont, Anne-Laure; Metz, Alexandra; Lemmers, Céline; Ango, Fabrice; Fagni, Laurent; Lory, Philippe; Mezghrani, Alexandre

    2014-08-01

    Episodic ataxia type-2 (EA2) is a dominantly inherited human neurological disorder caused by loss of function mutations in the CACNA1A gene, which encodes the CaV2.1 subunit of P/Q-type voltage-gated calcium channels. It remains however unknown whether the deficit of cerebellar CaV2.1 in adult is in direct link with the disease. To address this issue, we have used lentiviral based-vector RNA interference (RNAi) to knock-down CaV2.1 expression in the cerebellum of adult mice. We show that suppression of the P/Q-type channels in Purkinje neurons induced motor abnormalities, such as imbalance and ataxic gait. Interestingly, moderate channel suppression caused no basal ataxia, while β-adrenergic activation and exercise mimicked stress induced motor disorders. Moreover, stress-induced ataxia was stable, non-progressive and totally abolished by acetazolamide, a carbonic anhydrase inhibitor used to treat EA2. Altogether, these data reveal that P/Q-type channel suppression in adult mice supports the episodic status of EA2 disease. PMID:24768804

  9. Adult stem cells from the hyaluronic acid-rich node and duct system differentiate into neuronal cells and repair brain injury.

    PubMed

    Lee, Seung J; Park, Sang H; Kim, Yu I; Hwang, Sunhee; Kwon, Patrick M; Han, In S; Kwon, Byoung S

    2014-12-01

    The existence of a hyaluronic acid-rich node and duct system (HAR-NDS) within the lymphatic and blood vessels was demonstrated previously. The HAR-NDS was enriched with small (3.0-5.0 μm in diameter), adult stem cells with properties similar to those of the very small embryonic-like stem cells (VSELs). Sca-1(+)Lin(-)CD45(-) cells were enriched approximately 100-fold in the intravascular HAR-NDS compared with the bone marrow. We named these adult stem cells "node and duct stem cells (NDSCs)." NDSCs formed colonies on C2C12 feeder layers, were positive for fetal alkaline phosphatase, and could be subcultured on the feeder layers. NDSCs were Oct4(+)Nanog(+)SSEA-1(+)Sox2(+), while VSELs were Oct4(+)Nanog(+)SSEA-1(+)Sox2(-). NDSCs had higher sphere-forming efficiency and proliferative potential than VSELs, and they were found to differentiate into neuronal cells in vitro. Injection of NDSCs into mice partially repaired ischemic brain damage. Thus, we report the discovery of potential adult stem cells that may be involved in tissue regeneration. The intravascular HAR-NDS may serve as a route that delivers these stem cells to their target tissues. PMID:25027245

  10. Monoclonal antibodies to a rat nestin fusion protein recognize a 220-kDa polypeptide in subsets of fetal and adult human central nervous system neurons and in primitive neuroectodermal tumor cells.

    PubMed Central

    Tohyama, T.; Lee, V. M.; Rorke, L. B.; Marvin, M.; McKay, R. D.; Trojanowski, J. Q.

    1993-01-01

    Nestin is the major intermediate filament protein of embryonic central nervous system (CNS) progenitor cells. To identify proteins involved in early stages of lineage commitment in the developing human CNS we generated monoclonal antibodies to a TrpE-rat nestin fusion protein. This resulted in a monoclonal antibody (designated NST11) that did not recognize authentic human nestin, but did recognize a novel neuron-specific human polypeptide expressed in a subset of embryonic and adult CNS neurons as well as in medulloblastomas. NST11 immunoreactivity was abundant in developing spinal cord motor neurons, but was extinguished in these neurons by 17 weeks gestation. NST11 also labeled Purkinje cells at 17 weeks gestation, but Purkinje cells continued to express the NST11 antigen throughout gestation as well as in the adult cerebellum, and NST11 immunoreactivity was more abundant in Purkinje cells than in any other human CNS neurons. No NST11 immunoreactivity was detected in cells of the adult human peripheral nervous system or in a variety of adult non-neural human tissues. Further, NST11 almost exclusively stained cerebellar medulloblastomas. In Western blots of immature and mature human cerebral and cerebellar extracts, NST11 did not bind human nestin, but did detect an immunoband with a molecular weight of 220 kd. A similar immunoband was detected in medulloblastoma-derived cell lines with a neuron-like phenotype. These findings suggest that the NST11 monoclonal antibody recognizes a novel protein expressed by a subpopulation of immature and mature human CNS neurons, medulloblastomas, and medulloblastoma-derived cell lines. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:7686344

  11. Demethylation regulation of BDNF gene expression in dorsal root ganglion neurons is implicated in opioid-induced pain hypersensitivity in rats.

    PubMed

    Chao, Yu-Chieh; Xie, Fang; Li, Xueyang; Guo, Ruijuan; Yang, Ning; Zhang, Chen; Shi, Rong; Guan, Yun; Yue, Yun; Wang, Yun

    2016-07-01

    Repeated administration of morphine may result in opioid-induced hypersensitivity (OIH), which involves altered expression of numerous genes, including brain-derived neurotrophic factor (BDNF) in dorsal root ganglion (DRG) neurons. Yet, it remains unclear how BDNF expression is increased in DRG neurons after repeated morphine treatment. DNA methylation is an important mechanism of epigenetic control of gene expression. In the current study, we hypothesized that the demethylation regulation of certain BDNF gene promoters in DRG neurons may contribute to the development of OIH. Real-time RT-PCR was used to assess changes in the mRNA transcription levels of major BDNF exons including exon I, II, IV, VI, as well as total BDNF mRNA in DRGs from rats after repeated morphine administration. The levels of exon IV and total BDNF mRNA were significantly upregulated by repeated morphine administration, as compared to that in saline control group. Further, ELISA array and immunocytochemistry study revealed a robust upregulation of BDNF protein expression in DRG neurons after repeated morphine exposure. Correspondingly, the methylation levels of BDNF exon IV promoter showed a significant downregulation by morphine treatment. Importantly, intrathecal administration of a BDNF antibody, but not control IgG, significantly inhibited mechanical hypersensitivity that developed in rats after repeated morphine treatment. Conversely, intrathecal administration of an inhibitor of DNA methylation, 5-aza-2'-deoxycytidine (5-aza-dC) markedly upregulated the BDNF protein expression in DRG neurons and enhanced the mechanical allodynia after repeated morphine exposure. Together, our findings suggest that demethylation regulation of BDNF gene promoter may be implicated in the development of OIH through epigenetic control of BDNF expression in DRG neurons. PMID:26970395

  12. The receptor protein tyrosine phosphatase HmLAR1 is up-regulated in the CNS of the adult medicinal leech following injury and is required for neuronal sprouting and regeneration.

    PubMed

    Sethi, Jasmine; Zhao, Bailey; Cuvillier-Hot, Virginie; Boidin-Wichlacz, Céline; Salzet, Michel; Macagno, Eduardo R; Baker, Michael W

    2010-12-01

    LAR-like receptor protein tyrosine phosphatases (RPTPs), which are abundantly expressed in the nervous systems of most if not all bilaterian animals thus far examined, have been implicated in regulating a variety of critical neuronal processes. These include neuronal pathfinding, adhesion and synaptogenesis during development and, in adult mammals, neuronal regeneration. Here we explored a possible role of a LAR-like RPTP (HmLAR1) in response to mechanical trauma in the adult nervous system of the medicinal leech. In situ hybridization and QPCR analyses of HmLAR1 expression in individual segmental ganglia revealed a significant up-regulation in receptor expression following CNS injury, both in situ and following a period in vitro. Furthermore, we observed up-regulation in the expression of the leech homologue of the Abelson tyrosine kinase, a putative signaling partner to LAR receptors, but not among other tyrosine kinases. The effects on neuronal regeneration were assayed by comparing growth across a nerve crush by projections of individual dorsal P neurons (P(D)) following single-cell injection of interfering RNAs against the receptor or control RNAs. Receptor RNAi led to a significant reduction in HmLAR1 expression by the injected cells and resulted in a significant decrease in sprouting and regenerative growth at the crush site relative to controls. These studies extend the role of the HmLARs from leech neuronal development to adult neuronal regeneration and provide a platform to investigate neuronal regeneration and gene regulation at the single cell level. PMID:20708686

  13. PTEN inhibitor bisperoxovanadium protects oligodendrocytes and myelin and prevents neuronal atrophy in adult rats following cervical hemicontusive spinal cord injury

    PubMed Central

    Walker, Chandler L.; Xu, Xiao-Ming

    2014-01-01

    Cervical spinal cord injury (SCI) damages axons and motor neurons responsible for ipsilateral forelimb function and causes demyelination and oligodendrocyte death. Inhibition of the phosphatase and tensin homologue, PTEN, promotes neural cell survival, neuroprotection and regeneration in vivo and in vitro. PTEN inhibition can also promote oligodendrocyte-mediated myelination of axons in vitro likely through Akt activation. We recently demonstrated that acute treatment with phosphatase PTEN inhibitor, bisperoxovanadium (bpV)-pic reduced tissue damage, neuron death, and promoted functional recovery after cervical hemi-contusion SCI. Evidence suggests bpV can promote myelin stability; however, bpV effects on myelination and oligodendrocytes in contusive SCI models are unclear. We hypothesized that bpV could increase myelin around the injury site through sparing or remyelination, and that bpV treatment may promote increased numbers of oligodendrocytes. Using histological and immunofluorescence labeling, we found that bpV treatment promoted significant spared white matter (30%; p < 0.01) and Luxol Fast Blue (LFB)+ myelin area rostral (Veh: 0.56 ± 0.01 vs. bpV: 0.64 ± 0.02; p < 0.05) and at the epicenter (Veh: 0.4175 ± 0.03 vs. bpV: 0.5400 ± 0.03; p < 0.05). VLF oligodendrocytes were also significantly greater with bpV therapy (109 ± 5.3 vs. Veh: 77 ± 2.7/mm2; p < 0.01). In addition, bpV increased mean motor neuron soma area versus vehicle-treatment (1.0 ± 0.02 vs. Veh: 0.77 ± 0.02) relative to Sham neuron size. This study provides key insight into additional cell and tissue effects that could contribute to bpV-mediated functional recovery observed after contusive cervical SCI. PMID:24582904

  14. Structure and performance of different DRG classification systems for neonatal medicine.

    PubMed

    Muldoon, J H

    1999-01-01

    There are a number of Diagnosis-Related Group (DRG) classification systems that have evolved over the past 2 decades, each with their own strengths and weaknesses. DRG systems are used for case-mix trending, utilization management and quality improvement, comparative reporting, prospective payment, and price negotiations. For any of these applications it is essential to know the accuracy with which the DRG system classifies patients, specifically for predicting resource use and also mortality. The objective of this study was to assess the adequacy of the three most commonly used DRG systems for neonatal patients-Medicare DRGs, All Patient Diagnosis-Related Groups (AP-DRGs), and All Patient Refined Diagnosis-Related Groups (APR-DRGs). A 2-part methodology is used to assess adequacy. The first part is a descriptive analysis that examines the structural characteristics of each system. This provides a framework for understanding the inherent strengths and weaknesses of each system and for interpreting their statistical performance. The second part examines the statistical performance of each system on a large nationally representative hospital database. The analysis identifies major differences in the structure and statistical performance of the three DRG systems for neonates. The Medicare DRGs are structurally the least developed and yield the poorest overall statistical performance (cost R2 = 0.292; mortality R2 = 0.083). The APR-DRGs are structurally the most developed and yield the best statistical performance (cost R2 = 0.627; mortality R2 = 0.416). The AP-DRGs are intermediate to Medicare DRGs and APR-DRGs, although closer to APR-DRGs (cost R2 = 0.507; mortality R2 = 0.304). An analysis of payment impacts and systematic effects identifies there are major systematic biases with the Medicare DRGs. At the patient level, there is substantial underpayment for surgical neonates, transferred-in neonates, neonates discharged to home health services, and neonates who die

  15. NKCC1 Activation Is Required for Myelinated Sensory Neurons Regeneration through JNK-Dependent Pathway.

    PubMed

    Mòdol, Laura; Santos, Daniel; Cobianchi, Stefano; González-Pérez, Francisco; López-Alvarez, Víctor; Navarro, Xavier

    2015-05-13

    After peripheral nerve injury, axons are able to regenerate, although specific sensory reinnervation and functional recovery are usually worse for large myelinated than for small sensory axons. The mechanisms that mediate the regeneration of different sensory neuron subpopulations are poorly known. The Na(+)-K(+)-Cl(-) cotransporter 1 (NKCC1) is particularly relevant in setting the intracellular chloride concentration. After axotomy, increased NKCC1 phosphorylation has been reported to be important for neurite outgrowth of sensory neurons; however, the mechanisms underlying its effects are still unknown. In the present study we used in vitro and in vivo models to assess the differential effects of blocking NKCC1 activity on the regeneration of different types of dorsal root ganglia (DRGs) neurons after sciatic nerve injury in the rat. We observed that blocking NKCC1 activity by bumetanide administration induces a selective effect on neurite outgrowth and regeneration of myelinated fibers without affecting unmyelinated DRG neurons. To further study the mechanism underlying NKCC1 effects, we also assessed the changes in mitogen-activated protein kinase (MAPK) signaling under NKCC1 modulation. The inhibition of NKCC1 activity in vitro and in vivo modified pJNK1/2/3 expression in DRG neurons. Together, our study identifies a mechanism selectively contributing to myelinated axon regeneration, and point out the role of Cl(-) modulation in DRG neuron regeneration and in the activation of MAPKs, particularly those belonging to the JNK family. PMID:25972170

  16. Time course of morphine's effects on adult hippocampal subgranular zone reveals preferential inhibition of cells in S phase of the cell cycle and a subpopulation of immature neurons.

    PubMed

    Arguello, A A; Harburg, G C; Schonborn, J R; Mandyam, C D; Yamaguchi, M; Eisch, A J

    2008-11-11

    Opiates, such as morphine, decrease neurogenesis in the adult hippocampal subgranular zone (SGZ), raising the possibility that decreased neurogenesis contributes to opiate-induced cognitive deficits. However, there is an incomplete understanding of how alterations in cell cycle progression and progenitor maturation contribute to this decrease. The present study examined how morphine regulates progenitor cell cycle, cell death and immature SGZ neurons (experiment 1) as well as the progression of SGZ progenitors through key stages of maturation (experiment 2). In experiment 1, mice received sham or morphine pellets (s.c., 0 and 48 h) and bromodeoxyuridine (BrdU) 2 h prior to sacrifice (24, 72 or 96 h). Morphine decreased both the number of S phase and total cycling cells, as there were fewer cells immunoreactive (IR) for the S phase marker BrdU and the cell cycle marker Ki67. The percentage of Ki67-IR cells that were BrdU-IR was decreased after 24 but not 96 h of morphine, suggesting a disproportionate effect on S phase cells relative to all cycling cells at this time point. Cell death (activated caspase-3 counts) was increased after 24 but not 96 h. In experiment 2, nestin-green fluorescent protein (GFP) mice given BrdU 1 day prior to morphine or sham surgery (0 and 48 h, sacrifice 96 h) had fewer Ki67-IR cells, but no change in BrdU-IR cell number, suggesting that this population of BrdU-IR cells was less sensitive to morphine. Interestingly, examination of key stages of progenitor cell maturation revealed that morphine increased the percent of BrdU-IR cells that were type 2b and decreased the percent that were immature neurons. These data suggest that chronic morphine decreases SGZ neurogenesis by inhibiting dividing cells, particularly those in S phase, and progenitor cell progression to a more mature neuronal stage. PMID:18832014

  17. Short stressor induced long-lasting increases of vasopressin stores in hypothalamic corticotropin-releasing hormone (CRH) neurons in adult rats.

    PubMed

    Schmidt, E D; Binnekade, R; Janszen, A W; Tilders, F J

    1996-09-01

    Recently, we demonstrated that single administration of interleukin-1 beta (IL-1) to adult rats induces a long-lasting (weeks) increase of vasopressin (AVP) stores in terminals of CRH neurons in the external zone of the median eminence (ZEME). This is accompanied by hypersecretion of AVP into the pituitary portal circulation and long-lasting hyperresponsiveness of the hypothalamo-pituitary-adrenal (HPA) axis to stressors. Here, we determine whether this form of plasticity of hypothalamic CRH neurons is specific for IL-1 or represents a general response to a stressor. Single exposure of rats to lipopolysaccharide (LPS), IL-1, brain surgery or electric footshocks increases the AVP stores in the ZEME 7 and 11 days later. Exposure to insulin or ether does not affect the AVP stores. The stressors have little or no effect on the CRH stores in the ZEME. The amplitude of the increase in AVP as measured 7-11 days after stimulation correlates with the overall ACTH response to the stressor (area under curve, r = 0.89, P < 0.0001), with the peak ACTH levels (r = 0.52, P < 0.05), but not with the duration of the ACTH response nor with any parameter of the corticosterone response. Administration of ACTH or corticosterone at doses that mimic stress-induced plasma levels does not increase AVP stores 7 days later. We conclude that long-lasting increases of AVP stores in CRH terminals in the ZEME can be induced by various stressors and postulate that the amplitude of such increases depends on the degree of activation of the CRH neurons by the stressor. (NWO grant: 900-543-101.) PMID:8877819

  18. Distinct effects of pramipexole on the proliferation of adult mouse sub-ventricular zone-derived cells and the appearance of a neuronal phenotype.

    PubMed

    Merlo, Sara; Canonico, Pier Luigi; Sortino, Maria Angela

    2011-05-01

    Pramipexole (PPX) is a dopamine agonist with an 8-fold higher affinity for D3 than D2 receptor, whose efficacy in the treatment of Parkinson's disease is based on dopamine agonistic activity. PPX has also been recently shown to be endowed with neuroprotective activity and neurogenic potential. The aim of this study was a more detailed characterization of PPX-induced neurogenesis. Both D2 and D3 receptors are expressed in floating and differentiated neurospheres obtained from the sub-ventricular zone (SVZ) of adult mice. Treatment of secondary neurospheres with 10 μM PPX causes a marked induction of cell proliferation, assessed by enhanced cell number and S phase population at cell cycle analysis. Stimulation of proliferation by PPX is still detectable in plated neurospheres before the onset of migration and differentiation, as by enhanced BrdU incorporation. This effect is sensitive to the selective D3 dopamine receptor antagonist U99194A, as well as to sulpiride. A 24 h treatment with PPX does not modify the morphology of neurosphere-derived cells, but causes an increase of glial fibrillary acidic protein (GFAP)-positive cells, an effect sensitive to both D2 and D3 antagonism. Differentiation toward the neuronal lineage is increased by PPX as shown by enhancement of the cell population positive to the early neuronal marker doublecortin (DCX) at 24 h and the mature neuronal marker microtubule associated protein (MAP2) at 72 h. This effect is not modified by treatment with U99194A and is mimicked by BDNF. Accordingly, PPX increases BDNF release with a mechanism involving D2 but not D3 receptors. PMID:21272591

  19. Programming of Dopaminergic Neurons by Neonatal Sex Hormone Exposure: Effects on Dopamine Content and Tyrosine Hydroxylase Expression in Adult Male Rats

    PubMed Central

    Espinosa, Pedro; Silva, Roxana A.; Sanguinetti, Nicole K.; Venegas, Francisca C.; Riquelme, Raul; González, Luis F.; Cruz, Gonzalo; Renard, Georgina M.; Moya, Pablo R.; Sotomayor-Zárate, Ramón

    2016-01-01

    We sought to determine the long-term changes produced by neonatal sex hormone administration on the functioning of midbrain dopaminergic neurons in adult male rats. Sprague-Dawley rats were injected subcutaneously at postnatal day 1 and were assigned to the following experimental groups: TP (testosterone propionate of 1.0 mg/50 μL); DHT (dihydrotestosterone of 1.0 mg/50 μL); EV (estradiol valerate of 0.1 mg/50 μL); and control (sesame oil of 50 μL). At postnatal day 60, neurochemical studies were performed to determine dopamine content in substantia nigra-ventral tegmental area and dopamine release in nucleus accumbens. Molecular (mRNA expression of tyrosine hydroxylase) and cellular (tyrosine hydroxylase immunoreactivity) studies were also performed. We found increased dopamine content in substantia nigra-ventral tegmental area of TP and EV rats, in addition to increased dopamine release in nucleus accumbens. However, neonatal exposure to DHT, a nonaromatizable androgen, did not affect midbrain dopaminergic neurons. Correspondingly, compared to control rats, levels of tyrosine hydroxylase mRNA and protein were significantly increased in TP and EV rats but not in DHT rats, as determined by qPCR and immunohistochemistry, respectively. Our results suggest an estrogenic mechanism involving increased tyrosine hydroxylase expression, either by direct estrogenic action or by aromatization of testosterone to estradiol in substantia nigra-ventral tegmental area. PMID:26904299

  20. Loss of Nogo receptor homolog NgR2 alters spine morphology of CA1 neurons and emotionality in adult mice

    PubMed Central

    Borrie, Sarah C.; Sartori, Simone B.; Lehmann, Julian; Sah, Anupam; Singewald, Nicolas; Bandtlow, Christine E.

    2014-01-01

    Molecular mechanisms which stabilize dendrites and dendritic spines are essential for regulation of neuronal plasticity in development and adulthood. The class of Nogo receptor proteins, which are critical for restricting neurite outgrowth inhibition signaling, have been shown to have roles in developmental, experience and activity induced plasticity. Here we investigated the role of the Nogo receptor homolog NgR2 in structural plasticity in a transgenic null mutant for NgR2. Using Golgi-Cox staining to analyze morphology, we show that loss of NgR2 alters spine morphology in adult CA1 pyramidal neurons of the hippocampus, significantly increasing mushroom-type spines, without altering dendritic tree complexity. Furthermore, this shift is specific to apical dendrites in distal CA1 stratum radiatum (SR). Behavioral alterations in NgR2−/− mice were investigated using a battery of standardized tests and showed that whilst there were no alterations in learning and memory in NgR2−/− mice compared to littermate controls, NgR2−/− displayed reduced fear expression in the contextual conditioned fear test, and exhibited reduced anxiety- and depression-related behaviors. This suggests that the loss of NgR2 results in a specific phenotype of reduced emotionality. We conclude that NgR2 has role in maintenance of mature spines and may also regulate fear and anxiety-like behaviors. PMID:24860456

  1. Effects of embryonic ethanol exposure at low doses on neuronal development, voluntary ethanol consumption and related behaviors in larval and adult zebrafish: Role of hypothalamic orexigenic peptides.

    PubMed

    Sterling, M E; Chang, G-Q; Karatayev, O; Chang, S Y; Leibowitz, S F

    2016-05-01

    Embryonic exposure to ethanol is known to affect neurochemical systems in rodents and increase alcohol drinking and related behaviors in humans and rodents. With zebrafish emerging as a powerful tool for uncovering neural mechanisms of numerous diseases and exhibiting similarities to rodents, the present report building on our rat studies examined in zebrafish the effects of embryonic ethanol exposure on hypothalamic neurogenesis, expression of orexigenic neuropeptides, and voluntary ethanol consumption and locomotor behaviors in larval and adult zebrafish, and also effects of central neuropeptide injections on these behaviors affected by ethanol. At 24h post-fertilization, zebrafish embryos were exposed for 2h to ethanol, at low concentrations of 0.25% and 0.5%, in the tank water. Embryonic ethanol compared to control dose-dependently increased hypothalamic neurogenesis and the proliferation and expression of the orexigenic peptides, galanin (GAL) and orexin (OX), in the anterior hypothalamus. These changes in hypothalamic peptide neurons were accompanied by an increase in voluntary consumption of 10% ethanol-gelatin and in novelty-induced locomotor and exploratory behavior in adult zebrafish and locomotor activity in larvae. After intracerebroventricular injection, these peptides compared to vehicle had specific effects on these behaviors altered by ethanol, with GAL stimulating consumption of 10% ethanol-gelatin more than plain gelatin food and OX stimulating novelty-induced locomotor behavior while increasing intake of food and ethanol equally. These results, similar to those obtained in rats, suggest that the ethanol-induced increase in genesis and expression of these hypothalamic peptide neurons contribute to the behavioral changes induced by embryonic exposure to ethanol. PMID:26778786

  2. Adolescent, but Not Adult, Binge Ethanol Exposure Leads to Persistent Global Reductions of Choline Acetyltransferase Expressing Neurons in Brain

    PubMed Central

    Vetreno, Ryan P.; Broadwater, Margaret; Liu, Wen; Spear, Linda P.; Crews, Fulton T.

    2014-01-01

    During the adolescent transition from childhood to adulthood, notable maturational changes occur in brain neurotransmitter systems. The cholinergic system is composed of several distinct nuclei that exert neuromodulatory control over cognition, arousal, and reward. Binge drinking and alcohol abuse are common during this stage, which might alter the developmental trajectory of this system leading to long-term changes in adult neurobiology. In Experiment 1, adolescent intermittent ethanol (AIE; 5.0 g/kg, i.g., 2-day on/2-day off from postnatal day [P] 25 to P55) treatment led to persistent, global reductions of choline acetyltransferase (ChAT) expression. Administration of the Toll-like receptor 4 agonist lipopolysaccharide to young adult rats (P70) produced a reduction in ChAT+IR that mimicked AIE. To determine if the binge ethanol-induced ChAT decline was unique to the adolescent, Experiment 2 examined ChAT+IR in the basal forebrain following adolescent (P28–P48) and adult (P70–P90) binge ethanol exposure. Twenty-five days later, ChAT expression was reduced in adolescent, but not adult, binge ethanol-exposed animals. In Experiment 3, expression of ChAT and vesicular acetylcholine transporter expression was found to be significantly reduced in the alcoholic basal forebrain relative to moderate drinking controls. Together, these data suggest that adolescent binge ethanol decreases adult ChAT expression, possibly through neuroimmune mechanisms, which might impact adult cognition, arousal, or reward sensitivity. PMID:25405505

  3. Prion-like propagation of mutant SOD1 misfolding and motor neuron disease spread along neuroanatomical pathways.

    PubMed

    Ayers, Jacob I; Fromholt, Susan E; O'Neal, Veronica M; Diamond, Jeffrey H; Borchelt, David R

    2016-01-01

    A hallmark feature of amyotrophic lateral sclerosis (ALS) is that symptoms appear to spread along neuroanatomical pathways to engulf the motor nervous system, suggesting a propagative toxic entity could be involved in disease pathogenesis. Evidence for such a propagative entity emerged recently in studies using mice that express G85R-SOD1 mutant protein fused to YFP (G85R-SOD1:YFP). Heterozygous G85R-SOD1:YFP transgenic mice do not develop ALS symptoms out to 20 months of age. However, when newborns are injected with spinal homogenates from paralyzed mutant SOD1 mice, the G85R-SOD1:YFP mice develop paralysis as early as 6 months of age. We now demonstrate that injecting spinal homogenates from paralyzed mutant SOD1 mice into the sciatic nerves of adult G85R-SOD1:YFP mice produces a spreading motor neuron disease within 3.0 ± 0.2 months of injection. The formation of G85R-SOD1:YFP inclusion pathology spreads slowly in this model system; first appearing in the ipsilateral DRG, then lumbar spinal cord, before spreading rostrally up to the cervical cord by the time mice develop paralysis. Reactive astrogliosis mirrors the spread of inclusion pathology and motor neuron loss is most severe in lumbar cord. G85R-SOD1:YFP inclusion pathology quickly spreads to discrete neurons in the brainstem and midbrain that are synaptically connected to spinal neurons, suggesting a trans-synaptic propagation of misfolded protein. Taken together, the data presented here describe the first animal model that recapitulates the spreading phenotype observed in patients with ALS, and implicates the propagation of misfolded protein as a potential mechanism for the spreading of motor neuron disease. PMID:26650262

  4. Acrylamide Retards the Slow Axonal Transport of Neurofilaments in Rat Cultured Dorsal Root Ganglia Neurons and the Corresponding Mechanisms.

    PubMed

    An, Lihong; Li, Guozhen; Si, Jiliang; Zhang, Cuili; Han, Xiaoying; Wang, Shuo; Jiang, Lulu; Xie, Keqin

    2016-05-01

    Chronic acrylamide (ACR) exposure induces peripheral-central axonopathy in occupational workers and laboratory animals, but the underlying mechanisms remain unclear. In this study, we first investigated the effects of ACR on slow axonal transport of neurofilaments in cultured rat dorsal root ganglia (DRG) neurons through live-cell imaging approach. Then for the underlying mechanisms exploration, the protein level of neurofilament subunits, motor proteins kinesin and dynein, and dynamitin subunit of dynactin in DRG neurons were assessed by western blotting and the concentrations of ATP was detected using ATP Assay Kit. The results showed that ACR treatment results in a dose-dependent decrease of slow axonal transport of neurofilaments. Furthermore, ACR intoxication significantly increases the protein levels of the three neurofilament subunits (NF-L, NF-M, NF-H), kinesin, dynein, and dynamitin subunit of dynactin in DRG neurons. In addition, ATP le