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Sample records for adult drg neurons

  1. Differential role of GDNF and NGF in the maintenance of two TTX-resistant sodium channels in adult DRG neurons.

    PubMed

    Fjell, J; Cummins, T R; Dib-Hajj, S D; Fried, K; Black, J A; Waxman, S G

    1999-04-20

    Following sciatic nerve transection, the electrophysiological properties of small dorsal root ganglion (DRG) neurons are markedly altered, with attenuation of TTX-R sodium currents and the appearance of rapidly repriming TTX-S currents. The reduction in TTX-R currents has been attributed to a down-regulation of sodium channels SNS/PN3 and NaN. While infusion of exogenous NGF to the transected nerve restores SNS/PN3 transcripts to near-normal levels in small DRG neurons, TTX-R sodium currents are only partially rescued. Binding of the isolectin IB4 distinguishes two subpopulations of small DRG neurons: IB4+ neurons, which express receptors for the GDNF family of neurotrophins, and IB4- neurons that predominantly express TrkA. We show here that SNS/PN3 is expressed in approximately one-half of both IB4+ and IB4- DRG neurons, while NaN is preferentially expressed in IB4+ neurons. Whole-cell patch-clamp studies demonstrate that TTX-R sodium currents in IB4+ neurons have a more hyperpolarized voltage-dependence of activation and inactivation than do IB4- neurons, suggesting different electrophysiological properties for SNS/PN3 and NaN. We confirm that NGF restores SNS/PN3 mRNA levels in DRG neurons in vitro and demonstrate that the trk antagonist K252a blocks this rescue. The down-regulation of NaN mRNA is, nevertheless, not rescued by NGF-treatment in either IB4+ or IB4- neurons and NGF-treatment in vitro does not significantly increase the peak amplitude of the TTX-R current in small DRG neurons. In contrast, GDNF-treatment causes a twofold increase in the peak amplitude of TTX-R sodium currents and restores both SNS/PN3 and NaN mRNA to near-normal levels in IB4+ neurons. These observations provide a mechanism for the partial restoration of TTX-R sodium currents by NGF in axotomized DRG neurons, and demonstrate that the neurotrophins NGF and GDNF differentially regulate sodium channels SNS/PN3 and NaN. PMID:10216225

  2. The effect of neurotrophic factors on morphology, TRPV1 expression and capsaicin responses of cultured human DRG sensory neurons.

    PubMed

    Anand, U; Otto, W R; Casula, M A; Day, N C; Davis, J B; Bountra, C; Birch, R; Anand, P

    2006-05-15

    We have studied the effect of key neurotrophic factors (NTFs) on morphology, levels of the vanilloid receptor-1 (TRPV1) and responses to capsaicin in adult human sensory neurons in vitro. Avulsed dorsal root ganglia (DRG, n = 5) were cultured with or without a combination of nerve growth factor (NGF), glial cell (line)-derived growth factor (GDNF) and neurotrophin3 (NT3) for 5 days. In the absence of NTFs, the diameter of neurons ranged from 20 to 100 microm (mean 42 +/- 4 microm). Adding NTFs caused a significant increase in neuronal sizes, up to 120 microm (mean diameter 62 +/- 5 microm, P < 0.01, t-test), an overall 35% increase of TRPV1-positive neurons (P < 0.003), and notably of large TRPV1-positive neurons > 80 microm (P < 0.05). Responses to capsaicin were significantly enhanced with calcium ratiometry (P < 0.0001). Short duration (1h) exposure of dissociated sensory neurons to NTFs increased numbers of TRPV1-positive neurons, but not of TRPV3, Nav 1.8 and IK1 and the morphological size-distribution remained similar to intact post-mortem DRG neurons. NTFs thus increase size, elevate TRPV1 levels and enhance capsaicin responses in cultured human DRG neurons; these changes may relate to pathophysiology in disease states, and provide an in vitro model to study novel analgesics. PMID:16481104

  3. In vivo NGF deprivation reduces SNS expression and TTX-R sodium currents in IB4-negative DRG neurons.

    PubMed

    Fjell, J; Cummins, T R; Fried, K; Black, J A; Waxman, S G

    1999-02-01

    Recent evidence suggests that changes in sodium channel expression and localization may be involved in some pathological pain syndromes. SNS, a tetrodotoxin-resistant (TTX-R) sodium channel, is preferentially expressed in small dorsal root ganglion (DRG) neurons, many of which are nociceptive. TTX-R sodium currents and SNS mRNA expression have been shown to be modulated by nerve growth factor (NGF) in vitro and in vivo. To determine whether SNS expression and TTX-R currents in DRG neurons are affected by reduced levels of systemic NGF, we immunized adult rats with NGF, which causes thermal hypoalgesia in rats with high antibody titers to NGF. DRG neurons cultured from rats with high antibody titers to NGF, which do not bind the isolectin IB4 (IB4(-)) but do express TrkA, were studied with whole cell patch-clamp and in situ hybridization. Mean TTX-R sodium current density was decreased from 504 +/- 77 pA/pF to 307 +/- 61 pA/pF in control versus NGF-deprived neurons, respectively. In comparison, the mean TTX-sensitive sodium current density was not significantly different between control and NGF-deprived neurons. Quantification of SNS mRNA hybridization signal showed a significant decrease in the signal in NGF-deprived neurons compared with the control neurons. The data suggest that NGF has a major role in the maintenance of steady-state levels of TTX-R sodium currents and SNS mRNA in IB4(-) DRG neurons in adult rats in vivo. PMID:10036280

  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. 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

  6. Cutaneous and colonic rat DRG neurons differ with respect to both baseline and PGE2-induced changes in passive and active electrophysiological properties.

    PubMed

    Gold, Michael S; Traub, Richard J

    2004-06-01

    This study was designed to test the hypotheses that pain syndromes associated with specific body regions reflect unique properties of sensory neurons innervating these regions and/or unique responses of these afferents to tissue damage. Acutely dissociated adult rat dorsal root ganglia (DRG) neurons retrogradely labeled from either the colon or the glabrous skin of the hindpaw were studied by whole cell patch-clamp recording in current-clamp mode. Two populations of colonic afferent neurons were studied: pelvic afferents (arising from L(6), S(1), and S(2) DRG = LS DRG) and hypogastric/lumbar colonic afferents (arising from T(13), L(1), and L(2) DRG = TL DRG). Passive and active electrophysiological properties were studied before and after application prostaglandin E(2) (PGE(2)). We observed marked differences between cutaneous and colonic sensory neurons with respect to baseline passive and active electrophysiological properties as well as both the magnitude and pattern of PGE(2)-induced changes in excitability, passive, and active properties. There were also significant differences between TL and LS neurons with respect to baseline and PGE(2)-induced changes in several passive and active electrophysiological properties. Our results suggest that differences between cutaneous and colonic neurons reflect differences in pattern and/or density of ionic currents present in the plasma membrane. More interestingly, the ionic currents underlying the PGE(2)-induced sensitization of cutaneous neurons appeared to differ from those underlying the sensitization of colonic neurons. The implication of this observation is that it may be possible, in fact necessary, to treat pain arising from specific body regions with unique therapeutic interventions. PMID:14736864

  7. TNF-α contributes to up-regulation of Nav1.3 and Nav1.8 in DRG neurons following motor fiber injury.

    PubMed

    He, Xin-Hua; Zang, Ying; Chen, Xi; Pang, Rui-Ping; Xu, Ji-Tian; Zhou, Xiang; Wei, Xu-Hong; Li, Yong-Yong; Xin, Wen-Jun; Qin, Zhi-Hai; Liu, Xian-Guo

    2010-11-01

    A large body of evidence has demonstrated that the ectopic discharges of action potentials in primary afferents, resulted from the abnormal expression of voltage gated sodium channels (VGSCs) in dorsal root ganglion (DRG) neurons following peripheral nerve injury are important for the development of neuropathic pain. However, how nerve injury affects the expression of VGSCs is largely unknown. Here, we reported that selective injury of motor fibers by L5 ventral root transection (L5-VRT) up-regulated Nav1.3 and Nav1.8 at both mRNA and protein level and increased current densities of TTX-S and TTX-R channels in DRG neurons, suggesting that nerve injury may up-regulate functional VGSCs in sensory neurons indirectly. As the up-regulated Nav1.3 and Nav1.8 were highly co-localized with TNF-α, we tested the hypothesis that the increased TNF-α may lead to over-expression of the sodium channels. Indeed, we found that peri-sciatic administration of recombinant rat TNF-α (rrTNF) without any nerve injury, which produced lasting mechanical allodynia, also up-regulated Nav1.3 and Nav1.8 in DRG neurons in vivo and that rrTNF enhanced the expression of Nav1.3 and Nav1.8 in cultured adult rat DRG neurons in a dose-dependent manner. Furthermore, inhibition of TNF-α synthesis, which prevented neuropathic pain, strongly inhibited the up-regulation of Nav1.3 and Nav1.8. The up-regulation of the both channels following L5-VRT was significantly lower in TNF receptor 1 knockout mice than that in wild type mice. These data suggest that increased TNF-α may be responsible for up-regulation of Nav1.3 and Nav1.8 in uninjured DRG neurons following nerve injury. PMID:20638792

  8. 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

  9. Allotransplanted DRG neurons or Schwann cells affect functional recovery in a rodent model of sciatic nerve injury

    PubMed Central

    Liu, Weimin; Markman, John D.; Gelbard, Harris A.; Huang, Jason H.

    2015-01-01

    Objective In this study, the functional recoveries of Sprague-Dawley rats following repair of a complete sciatic nerve transection using allotransplanted dorsal root ganglion (DRG) neurons or Schwann cells were examined using a number of outcome measures. Methods Four groups were compared: (1) repair with a nerve guide conduit seeded with allotransplanted Schwann cells harvested from Wistar rats, (2) repair with a nerve guide conduit seeded with DRG neurons, (3) repair with solely a nerve guide conduit, and (4) sham-surgery animals where the sciatic nerve was left intact. The results corroborated our previous reported histology findings and measures of immunogenicity. Results The Wistar-DRG-treated group achieved the best recovery, significantly outperforming both the Wistar-Schwann group and the nerve guide conduit group in the Von Frey assay of touch response (P < 0.05). Additionally, Wistar-DRG and Wistar-Schwann seeded repairs showed lower frequency and severity in an autotomy measure of the self-mutilation of the injured leg because of neuralgia. Conclusion These results suggest that in complete peripheral nerve transections, surgical repair using nerve guide conduits with allotransplanted DRG and Schwann cells may improve recovery, especially DRG neurons, which elicit less of an immune response. PMID:24836462

  10. Calmodulin regulates current density and frequency-dependent inhibition of sodium channel Nav1.8 in DRG neurons.

    PubMed

    Choi, Jin-Sung; Hudmon, Andy; Waxman, Stephen G; Dib-Hajj, Sulayman D

    2006-07-01

    Sodium channel Nav1.8 produces a slowly inactivating, tetrodotoxin-resistant current, characterized by recovery from inactivation with fast and slow components, and contributes a substantial fraction of the current underlying the depolarizing phase of the action potential of dorsal root ganglion (DRG) neurons. Nav1.8 C-terminus carries a conserved calmodulin-binding isoleucine-glutamine (IQ) motif. We show here that calmodulin coimmunoprecipitates with endogenous Nav1.8 channels from native DRG, suggesting that the two proteins can interact in vivo. Treatment of native DRG neurons with a calmodulin-binding peptide (CBP) reduced the current density of Nav1.8 by nearly 65%, without changing voltage dependency of activation or steady-state inactivation. To investigate the functional role of CaM binding to the IQ motif in the Nav1.8 C-terminus, the IQ dipeptide was substituted by DE; we show that this impairs the binding of CaM to the IQ motif. Mutant Nav1.8IQ/DE channels produce currents with roughly 50% amplitude, but with unchanged voltage dependency of activation and inactivation when expressed in DRG neurons from Nav1.8-null mice. We also show that blocking the interaction of CaM and Nav1.8 using CBP or the IQ/DE substitution causes a buildup of inactivated channels and, in the case of the IQ/DE mutation, stimulation even at a low frequency of 0.1 Hz significantly enhances the frequency-dependent inhibition of the Nav1.8 current. This study presents, for the first time, evidence that calmodulin associates with a sodium channel, Nav1.8, in native neurons, and demonstrates a regulation of Nav1.8 currents that can significantly affect electrogenesis of DRG neurons in which Nav1.8 is normally expressed. PMID:16598065

  11. Contribution of Na(v)1.8 sodium channels to action potential electrogenesis in DRG neurons.

    PubMed

    Renganathan, M; Cummins, T R; Waxman, S G

    2001-08-01

    C-type dorsal root ganglion (DRG) neurons can generate tetrodotoxin-resistant (TTX-R) sodium-dependent action potentials. However, multiple sodium channels are expressed in these neurons, and the molecular identity of the TTX-R sodium channels that contribute to action potential production in these neurons has not been established. In this study, we used current-clamp recordings to compare action potential electrogenesis in Na(v)1.8 (+/+) and (-/-) small DRG neurons maintained for 2-8 h in vitro to examine the role of sodium channel Na(v)1.8 (alpha-SNS) in action potential electrogenesis. Although there was no significant difference in resting membrane potential, input resistance, current threshold, or voltage threshold in Na(v)1.8 (+/+) and (-/-) DRG neurons, there were significant differences in action potential electrogenesis. Most Na(v)1.8 (+/+) neurons generate all-or-none action potentials, whereas most of Na(v)1.8 (-/-) neurons produce smaller graded responses. The peak of the response was significantly reduced in Na(v)1.8 (-/-) neurons [31.5 +/- 2.2 (SE) mV] compared with Na(v)1.8 (+/+) neurons (55.0 +/- 4.3 mV). The maximum rise slope was 84.7 +/- 11.2 mV/ms in Na(v)1.8 (+/+) neurons, significantly faster than in Na(v)1.8 (-/-) neurons where it was 47.2 +/- 1.3 mV/ms. Calculations based on the action potential overshoot in Na(v)1.8 (+/+) and (-/-) neurons, following blockade of Ca(2+) currents, indicate that Na(v)1.8 contributes a substantial fraction (80-90%) of the inward membrane current that flows during the rising phase of the action potential. We found that fast TTX-sensitive Na(+) channels can produce all-or-none action potentials in some Na(v)1.8 (-/-) neurons but, presumably as a result of steady-state inactivation of these channels, electrogenesis in Na(v)1.8 (-/-) neurons is more sensitive to membrane depolarization than in Na(v)1.8 (+/+) neurons, and, in the absence of Na(v)1.8, is attenuated with even modest depolarization. These observations

  12. 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

  13. 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

  14. alpha-SNS produces the slow TTX-resistant sodium current in large cutaneous afferent DRG neurons.

    PubMed

    Renganathan, M; Cummins, T R; Hormuzdiar, W N; Waxman, S G

    2000-08-01

    In this study, we used sensory neuron specific (SNS) sodium channel gene knockout (-/-) mice to ask whether SNS sodium channel produces the slow Na(+) current ("slow") in large (>40 microm diam) cutaneous afferent dorsal root ganglion (DRG) neurons. SNS wild-type (+/+) mice were used as controls. Retrograde Fluoro-Gold labeling permitted the definitive identification of cutaneous afferent neurons. Prepulse inactivation was used to separate the fast and slow Na(+) currents. Fifty-two percent of the large cutaneous afferent neurons isolated from SNS (+/+) mice expressed only fast-inactivating Na(+) currents ("fast"), and 48% expressed both fast and slow Na(+) currents. The fast and slow current densities were 0.90 +/- 0.12 and 0.39 +/- 0.16 nA/pF, respectively. Fast Na(+) currents were blocked completely by 300 nM tetrodotoxin (TTX), while slow Na(+) currents were resistant to 300 nM TTX, confirming that the slow Na(+) currents observed in large cutaneous DRG neurons are TTX-resistant (TTX-R). Slow Na(+) currents could not be detected in large cutaneous afferent neurons from SNS (-/-) mice; these cells expressed only fast Na(+) current, and it was blocked by 300 nM TTX. The fast Na(+) current density in SNS (-/-) neurons was 1.47 +/- 0. 14 nA/pF, approximately 60% higher than the current density observed in SNS (+/+) mice (P < 0.02). A low-voltage-activated TTX-R Na(+) current ("persistent") observed in small C-type neurons is not present in large cutaneous afferent neurons from either SNS (+/+) or SNS (-/-) mice. These results show that the slow TTX-R Na(+) current in large cutaneous afferent DRG is produced by the SNS sodium channel. PMID:10938298

  15. 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.

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

    PubMed

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

    2014-09-15

    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.

  17. 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

    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 I h current density in injured medium-sized DRG neurons. Our results proved that MeCbl might exert an analgesic effect through the inhibition I h current and then might inhibit the hyperexcitability of primary sensory neurons under neuropathic pain state.

  18. Human Na(v)1.8: enhanced persistent and ramp currents contribute to distinct firing properties of human DRG neurons.

    PubMed

    Han, Chongyang; Estacion, Mark; Huang, Jianying; Vasylyev, Dymtro; Zhao, Peng; Dib-Hajj, Sulayman D; Waxman, Stephen G

    2015-05-01

    Although species-specific differences in ion channel properties are well-documented, little has been known about the properties of the human Nav1.8 channel, an important contributor to pain signaling. Here we show, using techniques that include voltage clamp, current clamp, and dynamic clamp in dorsal root ganglion (DRG) neurons, that human Na(v)1.8 channels display slower inactivation kinetics and produce larger persistent current and ramp current than previously reported in other species. DRG neurons expressing human Na(v)1.8 channels unexpectedly produce significantly longer-lasting action potentials, including action potentials with half-widths in some cells >10 ms, and increased firing frequency compared with the narrower and usually single action potentials generated by DRG neurons expressing rat Na(v)1.8 channels. We also show that native human DRG neurons recapitulate these properties of Na(v)1.8 current and the long-lasting action potentials. Together, our results demonstrate strikingly distinct properties of human Na(v)1.8, which contribute to the firing properties of human DRG neurons. PMID:25787950

  19. 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

  20. 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.

  1. Contactin regulates the current density and axonal expression of tetrodotoxin-resistant but not tetrodotoxin-sensitive sodium channels in DRG neurons.

    PubMed

    Rush, Anthony M; Craner, Matthew J; Kageyama, Takashi; Dib-Hajj, Sulayman D; Waxman, Stephen G; Ranscht, Barbara

    2005-07-01

    Contactin, a glycosyl-phosphatidylinositol (GPI)-anchored predominantly neuronal cell surface glycoprotein, associates with sodium channels Nav1.2, Nav1.3 and Nav1.9, and enhances the density of these channels on the plasma membrane in mammalian expression systems. However, a detailed functional analysis of these interactions and of untested putative interactions with other sodium channel isoforms in mammalian neuronal cells has not been carried out. We examined the expression and function of sodium channels in small-diameter dorsal root ganglion (DRG) neurons from contactin-deficient (CNTN-/-) mice, compared to CNTN+/+ litter mates. Nav1.9 is preferentially expressed in isolectin B4 (IB4)-positive neurons and thus we used this marker to subdivide small-diameter DRG neurons. Using whole-cell patch-clamp recording, we observed a greater than two-fold reduction of tetrodotoxin-resistant (TTX-R) Nav1.8 and Nav1.9 current densities in IB4+ DRG neurons cultured from CNTN-/- vs. CNTN+/+ mice. Current densities for TTX-sensitive (TTX-S) sodium channels were unaffected. Contactin's effect was selective for IB4+ neurons as current densities for both TTX-R and TTX-S channels were not significantly different in IB4- DRG neurons from the two genotypes. Consistent with these results, we have demonstrated a reduction in Nav1.8 and Nav1.9 immunostaining on peripherin-positive unmyelinated axons in sciatic nerves from CNTN-/- mice but detected no changes in the expression for the two major TTX-S channels Nav1.6 and Nav1.7. These data provide evidence of a role for contactin in selectively regulating the cell surface expression and current densities of TTX-R but not TTX-S Na+ channel isoforms in nociceptive DRG neurons; this regulation could modulate the membrane properties and excitability of these neurons. PMID:16029194

  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.

  3. Purification and culture of adult rat dorsal root ganglia neurons.

    PubMed

    Delree, P; Leprince, P; Schoenen, J; Moonen, G

    1989-06-01

    To study the trophic requirements of adult rat dorsal root ganglia neurons (DRG) in vitro, we developed a purification procedure that yields highly enriched neuronal cultures. Forty to fifty ganglia are dissected from the spinal column of an adult rat. After enzymatic and mechanical dissociation of the ganglia, myelin debris are eliminated by centrifugation on a Percoll gradient. The resulting cell suspension is layered onto a nylon mesh with a pore size of 10 microns. Most of the neurons, the diameter of which ranged from 17 microns to greater than 100 microns, are retained on the upper surface of the sieve; most of the non-neuronal cells with a caliber of less than 10 microns after trypsinization go through it. Recovery of neurons is achieved by reversing the mesh onto a Petri dish containing culture medium. Neurons to non-neurons ratio is 1 to 10 in the initial cell suspension and 1 to 1 after separation. When these purified neurons are seeded at a density of 3,000 neurons/cm2 in 6 mm polyornithine-laminin (PORN-LAM) coated wells, neuronal survival (assessed by the ability to extend neurites), measured after 48 hr of culture, is very low (from 0 to 16%). Addition of nerve growth factor (NGF) does not improve neuronal survival. However, when neurons are cultured in the presence of medium conditioned (CM) by astrocytes or Schwann cells, 60-80% of the seeded, dye-excluding neurons survive. So, purified adult DRG neurons require for their short-term survival and regeneration in culture, a trophic support that is present in conditioned medium from PNS or CNS glia.(ABSTRACT TRUNCATED AT 250 WORDS)

  4. Epigenetic modification of DRG neuronal gene expression subsequent to nerve injury: Etiological contribution to complex regional pain syndromes (Part I)

    PubMed Central

    Wang, Fuzhou; Stefano, George B.; Kream, Richard M.

    2014-01-01

    DRG is of importance in relaying painful stimulation to the higher pain centers and therefore could be a crucial target for early intervention aimed at suppressing primary afferent stimulation. Complex regional pain syndrome (CRPS) is a common pain condition with an unknown etiology. Recently added new information enriches our understanding of CRPS pathophysiology. Researches on genetics, biogenic amines, neurotransmitters, and mechanisms of pain modulation, central sensitization, and autonomic functions in CRPS revealed various abnormalities indicating that multiple factors and mechanisms are involved in the pathogenesis of CRPS. Epigenetics refers to mitotically and meiotically heritable changes in gene expression that do not affect the DNA sequence. As epigenetic modifications potentially play an important role in inflammatory cytokine metabolism, neurotransmitter responsiveness, and analgesic sensitivity, they are likely key factors in the development of chronic pain. In this dyad review series, we systematically examine the nerve injury-related changes in the neurological system and their contribution to CRPS. In this part, we first reviewed and summarized the role of neural sensitization in DRG neurons in performing function in the context of pain processing. Particular emphasis is placed on the cellular and molecular changes after nerve injury as well as different models of inflammatory and neuropathic pain. These were considered as the potential molecular bases that underlie nerve injury-associated pathogenesis of CRPS. PMID:24961509

  5. Spinal nerve injury increases the percentage of cold-responsive DRG neurons.

    PubMed

    Djouhri, L; Wrigley, D; Thut, P D; Gold, M S

    2004-03-01

    We tested the hypothesis that cold allodynia, observed following nerve injury reflects change(s) in the cold responsiveness of sensory neurons. To test this hypothesis we assessed the impact of the spinal nerve ligation (SNL) model of nerve injury on the responses of cutaneous sensory neurons to cooling in vitro. Nerve injury induced a significant increase in the incidence of cold responsive cutaneous neurons in uninjured but not injured ganglia. Because an increase in the percentage of cold responsive neurons in uninjured ganglia should increase the total neuronal response to cooling of peripheral tissue, these findings suggest that cold allodynia reflects, at least in part, a change in sensory neurons. PMID:15094503

  6. Differential slow inactivation and use-dependent inhibition of Nav1.8 channels contribute to distinct firing properties in IB4+ and IB4- DRG neurons.

    PubMed

    Choi, Jin-Sung; Dib-Hajj, Sulayman D; Waxman, Stephen G

    2007-02-01

    Nociceptive dorsal root ganglion (DRG) neurons can be classified into nonpeptidergic IB(4)(+) and peptidergic IB(4)(-) subtypes, which terminate in different layers in dorsal horn and transmit pain along different ascending pathways, and display different firing properties. Voltage-gated, tetrodotoxin-resistant (TTX-R) Na(v)1.8 channels are expressed in both IB(4)(+) and IB(4)(-) cells and produce most of the current underlying the depolarizing phase of action potential (AP). Slow inactivation of TTX-R channels has been shown to regulate repetitive DRG neuron firing behavior. We show in this study that use-dependent reduction of Na(v)1.8 current in IB(4)(+) neurons is significantly stronger than that in IB(4)(-) neurons, although voltage dependency of activation and steady-state inactivation are not different. The time constant for entry of Na(v)1.8 into slow inactivation in IB(4)(+) neurons is significantly faster and more Na(v)1.8 enter the slow inactivation state than in IB(4)(-) neurons. In addition, recovery from slow inactivation of Na(v)1.8 in IB(4)(+) neurons is slower than that in IB(4)(-) neurons. Using current-clamp recording, we demonstrate a significantly higher current threshold for generation of APs and a longer latency to onset of firing in IB(4)(+), compared with those of IB(4)(-) neurons. In response to a ramp stimulus, IB(4)(+) neurons produce fewer APs and display stronger adaptation, with a faster decline of AP peak than IB(4)(-) neurons. Our data suggest that differential use-dependent reduction of Na(v)1.8 current in these two DRG subpopulations, which results from their different rate of entry into and recovery from the slow inactivation state, contributes to functional differences between these two neuronal populations. PMID:17108087

  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. VGLUTs and Glutamate Synthesis—Focus on DRG Neurons and Pain

    PubMed Central

    Malet, Mariana; Brumovsky, Pablo R.

    2015-01-01

    The amino acid glutamate is the principal excitatory transmitter in the nervous system, including in sensory neurons that convey pain sensation from the periphery to the brain. It is now well established that a family of membrane proteins, termed vesicular glutamate transporters (VGLUTs), serve a critical function in these neurons: they incorporate glutamate into synaptic vesicles. VGLUTs have a central role both under normal neurotransmission and pathological conditions, such as neuropathic or inflammatory pain. In the present short review, we will address VGLUTs in the context of primary afferent neurons. We will focus on the role of VGLUTs in pain triggered by noxious stimuli, peripheral nerve injury, and tissue inflammation, as mostly explored in transgenic mice. The possible interplay between glutamate biosynthesis and VGLUT-dependent packaging in synaptic vesicles, and its potential impact in various pain states will be presented. PMID:26633536

  9. VGLUTs and Glutamate Synthesis-Focus on DRG Neurons and Pain.

    PubMed

    Malet, Mariana; Brumovsky, Pablo R

    2015-12-02

    The amino acid glutamate is the principal excitatory transmitter in the nervous system, including in sensory neurons that convey pain sensation from the periphery to the brain. It is now well established that a family of membrane proteins, termed vesicular glutamate transporters (VGLUTs), serve a critical function in these neurons: they incorporate glutamate into synaptic vesicles. VGLUTs have a central role both under normal neurotransmission and pathological conditions, such as neuropathic or inflammatory pain. In the present short review, we will address VGLUTs in the context of primary afferent neurons. We will focus on the role of VGLUTs in pain triggered by noxious stimuli, peripheral nerve injury, and tissue inflammation, as mostly explored in transgenic mice. The possible interplay between glutamate biosynthesis and VGLUT-dependent packaging in synaptic vesicles, and its potential impact in various pain states will be presented.

  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 role of well-defined patterned substrata on the regeneration of DRG neuron pathfinding and integrin expression dynamics using chondroitin sulfate proteoglycans

    PubMed Central

    Hodgkinson, Gerald N.; Tresco, Patrick A.; Hlady, Vladimir

    2012-01-01

    Injured neurons intrinsically adapt to and partially overcome inhibitory proteoglycan expression in the central nervous system by upregulating integrin expression. It remains unclear however, to what extent varying proteoglycan concentrations influence the strength of this response, how rapidly neurons adapt to proteoglycans, and how pathfinding dynamics are altered over time as integrin expression is modulated in response to proteglycan signals. To investigate these quandaries, we created well-defined substrata in which postnatal DRG neuron pathfinding dynamics and growth cone integrin expression were interrogated as a function of proteoglycan substrata density. DRGs responded by upregulating integrin expression in a proteoglycan dose dependent fashion and exhibited robust outgrowth over all proteoglycan densities at initial time frames. However, after prolonged proteoglycan exposure, neurons exhibited decreasing velocities associated with increasing proteoglycan densities, while neurons growing on low proteoglycan levels exhibited robust outgrowth at all time points. Additionally, DRG outgrowth over proteoglycan density step boundaries, and a brief β1 integrin functional block proved that regeneration was integrin dependent and that DRGs exhibit delayed slowing and loss in persistence after even transient encounters with dense proteoglycan boundaries. These findings demonstrate the complexity of proteoglycan regulation on integrin expression and regenerative pathfinding. PMID:22436802

  12. Vector-mediated release of GABA attenuates pain-related behaviors and reduces NaV1.7 in DRG neurons

    PubMed Central

    Chattopadhyay, Munmun; Mata, Marina; Fink, David J.

    2012-01-01

    Pain is a common and debilitating accompaniment of neuropathy that occurs as a complication of diabetes. In the current study, we examined the effect of continuous release of gamma amino butyric acid (GABA), achieved by gene transfer of glutamic acid decarboxylase (GAD67) to dorsal root ganglia (DRG) in vivo using a nonreplicating herpes simplex virus (HSV)-based vector (vG) in a rat model of painful diabetic neuropathy (PDN). Subcutaneous inoculation of vG reduced mechanical hyperalgesia, thermal hyperalgesia and cold allodynia in rats with PDN. Continuous release of GABA from vector transduced cells in vivo prevented the increase in the voltage gated sodium channel isoform 1.7 (NaV1.7) protein that is characteristic of PDN. In vitro, infection of primary DRG neurons with vG prevented the increase in NaV1.7 resulting from exposure to hyperglycemia. The effect of vector-mediated GABA on NaV1.7 levels in vitro was blocked by phaclofen but not by bicuculline, a GABAB receptor effect that was blocked by pertussis toxin-(PTX) interference with Gα(i/o) function. Taken in conjunction with our previous observation that continuous activation of delta opioid receptors by vector-mediated release of enkephalin also prevents the increase in NaV1.7 in DRG exposed to hyperglycemia in vitro or in vivo, the observations in this report suggest a novel common mechanism through which activation of G protein coupled receptors (GPCR) in DRG neurons regulate the phenotype of the primary afferent. PMID:21486703

  13. 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

  14. Partial nerve injury induces electrophysiological changes in conducting (uninjured) nociceptive and nonnociceptive DRG neurons: Possible relationships to aspects of peripheral neuropathic pain and paresthesias

    PubMed Central

    Djouhri, Laiche; Fang, Xin; Koutsikou, Stella; Lawson, Sally N.

    2012-01-01

    Partial nerve injury leads to peripheral neuropathic pain. This injury results in conducting/uninterrupted (also called uninjured) sensory fibres, conducting through the damaged nerve alongside axotomised/degenerating fibres. In rats seven days after L5 spinal nerve axotomy (SNA) or modified-SNA (added loose-ligation of L4 spinal nerve with neuroinflammation-inducing chromic-gut), we investigated a) neuropathic pain behaviours and b) electrophysiological changes in conducting/uninterrupted L4 dorsal root ganglion (DRG) neurons with receptive fields (called: L4-receptive-field-neurons). Compared to pretreatment, modified-SNA rats showed highly significant increases in spontaneous-foot-lifting duration, mechanical-hypersensitivity/allodynia, and heat-hypersensitivity/hyperalgesia, that were significantly greater than after SNA, especially spontaneous-foot-lifting. We recorded intracellularly in vivo from normal L4/L5 DRG neurons and ipsilateral L4-receptive-field-neurons. After SNA or modified-SNA, L4-receptive-field-neurons showed the following: a) increased percentages of C-, Ad-, and Ab-nociceptors and cutaneous Aa/b-low-threshold mechanoreceptors with ongoing/spontaneous firing; b) spontaneous firing in C-nociceptors that originated peripherally; this was at a faster rate in modified-SNA than SNA; c) decreased electrical thresholds in A-nociceptors after SNA; d) hyperpolarised membrane potentials in A-nociceptors and Aa/b-low-threshold-mechanoreceptors after SNA, but not C-nociceptors; e) decreased somatic action potential rise times in C- and A-nociceptors, not Aa/b-low-threshold-mechanoreceptors. We suggest that these changes in subtypes of conducting/uninterrupted neurons after partial nerve injury contribute to the different aspects of neuropathic pain as follows: spontaneous firing in nociceptors to ongoing/spontaneous pain; spontaneous firing in Aa/b-low-threshold-mechanoreceptors to dysesthesias/paresthesias; and lowered A-nociceptor electrical thresholds

  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. 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

  17. 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

  18. Ca2+ toxicity due to reverse Na+/Ca2+ exchange contributes to degeneration of neurites of DRG neurons induced by a neuropathy-associated Nav1.7 mutation.

    PubMed

    Estacion, M; Vohra, B P S; Liu, S; Hoeijmakers, J; Faber, C G; Merkies, I S J; Lauria, G; Black, J A; Waxman, S G

    2015-09-01

    Gain-of-function missense mutations in voltage-gated sodium channel Nav1.7 have been linked to small-fiber neuropathy, which is characterized by burning pain, dysautonomia and a loss of intraepidermal nerve fibers. However, the mechanistic cascades linking Nav1.7 mutations to axonal degeneration are incompletely understood. The G856D mutation in Nav1.7 produces robust changes in channel biophysical properties, including hyperpolarized activation, depolarized inactivation, and enhanced ramp and persistent currents, which contribute to the hyperexcitability exhibited by neurons containing Nav1.8. We report here that cell bodies and neurites of dorsal root ganglion (DRG) neurons transfected with G856D display increased levels of intracellular Na(+) concentration ([Na(+)]) and intracellular [Ca(2+)] following stimulation with high [K(+)] compared with wild-type (WT) Nav1.7-expressing neurons. Blockade of reverse mode of the sodium/calcium exchanger (NCX) or of sodium channels attenuates [Ca(2+)] transients evoked by high [K(+)] in G856D-expressing DRG cell bodies and neurites. We also show that treatment of WT or G856D-expressing neurites with high [K(+)] or 2-deoxyglucose (2-DG) does not elicit degeneration of these neurites, but that high [K(+)] and 2-DG in combination evokes degeneration of G856D neurites but not WT neurites. Our results also demonstrate that 0 Ca(2+) or blockade of reverse mode of NCX protects G856D-expressing neurites from degeneration when exposed to high [K(+)] and 2-DG. These results point to [Na(+)] overload in DRG neurons expressing mutant G856D Nav1.7, which triggers reverse mode of NCX and contributes to Ca(2+) toxicity, and suggest subtype-specific blockade of Nav1.7 or inhibition of reverse NCX as strategies that might slow or prevent axon degeneration in small-fiber neuropathy. PMID:26156380

  19. Ca2+ toxicity due to reverse Na+/Ca2+ exchange contributes to degeneration of neurites of DRG neurons induced by a neuropathy-associated Nav1.7 mutation

    PubMed Central

    Estacion, M.; Vohra, B. P. S; Liu, S.; Hoeijmakers, J.; Faber, C. G.; Merkies, I. S. J.; Lauria, G.; Black, J. A.

    2015-01-01

    Gain-of-function missense mutations in voltage-gated sodium channel Nav1.7 have been linked to small-fiber neuropathy, which is characterized by burning pain, dysautonomia and a loss of intraepidermal nerve fibers. However, the mechanistic cascades linking Nav1.7 mutations to axonal degeneration are incompletely understood. The G856D mutation in Nav1.7 produces robust changes in channel biophysical properties, including hyperpolarized activation, depolarized inactivation, and enhanced ramp and persistent currents, which contribute to the hyperexcitability exhibited by neurons containing Nav1.8. We report here that cell bodies and neurites of dorsal root ganglion (DRG) neurons transfected with G856D display increased levels of intracellular Na+ concentration ([Na+]) and intracellular [Ca2+] following stimulation with high [K+] compared with wild-type (WT) Nav1.7-expressing neurons. Blockade of reverse mode of the sodium/calcium exchanger (NCX) or of sodium channels attenuates [Ca2+] transients evoked by high [K+] in G856D-expressing DRG cell bodies and neurites. We also show that treatment of WT or G856D-expressing neurites with high [K+] or 2-deoxyglucose (2-DG) does not elicit degeneration of these neurites, but that high [K+] and 2-DG in combination evokes degeneration of G856D neurites but not WT neurites. Our results also demonstrate that 0 Ca2+ or blockade of reverse mode of NCX protects G856D-expressing neurites from degeneration when exposed to high [K+] and 2-DG. These results point to [Na+] overload in DRG neurons expressing mutant G856D Nav1.7, which triggers reverse mode of NCX and contributes to Ca2+ toxicity, and suggest subtype-specific blockade of Nav1.7 or inhibition of reverse NCX as strategies that might slow or prevent axon degeneration in small-fiber neuropathy. PMID:26156380

  20. mu and delta opioid agonists at low concentrations decrease voltage-dependent K+ currents in F11 neuroblastoma x DRG neuron hybrid cells via cholera toxin-sensitive receptors.

    PubMed

    Fan, S F; Shen, K F; Crain, S M

    1993-03-12

    In a previous study, we showed that microM concentrations of mu or delta opioid agonists increase voltage-dependent outward K+ currents in neuroblastoma x DRG neuron hybrid F11 cells via pertussis toxin-sensitive receptors. The present study demonstrates that much lower concentrations (fM to nM) of these opioids (DAGO and DPDPE) decreased voltage-dependent outward K+ currents during step depolarization. The opioid antagonist, naloxone (3 nM) prevented these decreases in K+ current as did the cholera toxin subunits A or B (ca. 1 nM). Furthermore, the specific mu opioid receptor antagonist, beta-funaltrexamine (5 nM) blocked the decrease by DAGO and the specific delta antagonist, naltrindole (1 nM) blocked that by DPDPE. Acute GM1 ganglioside (1 microM) treatment markedly enhanced the efficacy of opioid-induced decrease in K+ current. After treating the cells with pertussis toxin (1 microgram/ml) for 2 days or more, these opioids decreased the K+ current even when tested at concentrations as high as 1 microM. These results indicate that the decrease in K+ current elicited in F11 cells by low concentrations of mu and delta opioid agonists resembles the opioid-induced prolongation of the action potential duration and decrease in voltage-dependent K+ conductance that occur in DRG neurons in primary cultures. The F11 cell line provides therefore a valuable model system for correlative pharmacologic, electrophysiologic and biochemical analyses of Gs-coupled, GM1 ganglioside-regulated excitatory opioid receptor functions, in addition to G(i)/G(o)-coupled inhibitory receptor functions, in sensory neurons.

  1. Involvement of voltage-gated sodium channel Na(v)1.8 in the regulation of the release and synthesis of substance P in adult mouse dorsal root ganglion neurons.

    PubMed

    Tang, He-Bin; Shiba, Eri; Li, Yu-Sang; Morioka, Norimitsu; Zheng, Tai-Xing; Ogata, Nobukuni; Nakata, Yoshihiro

    2008-10-01

    This study was conducted to determine whether Na(v)1.8 contributes to the release and/or synthesis of substance P (SP) in adult mice dorsal root ganglion (DRG) neurons. The SP released from cultured DRG neurons of Na(v)1.8 knock-out mice exposed to either capsaicin or KCl was significantly lower than that from wild-type (C57BL/6) mice based on a radioimmunoassay. The SP level of L6 DRG in Na(v)1.8 knock-out mice was also lower than that in wild-type mice. After chronic constriction injury (CCI) of the sciatic nerve, the level of SP decreased in the L6 ipsilateral DRG of wild-type but not Na(v)1.8 knock-out mice. The preprotachykinin-A (PPT-A) mRNAs in L4 - 6 DRGs of Na(v)1.8 knock-out mice also fell to half their normally abundant levels of expression. There were significant increases in Na(v)1.8 expression of the L6 contralateral DRG from wild-type mice and in the percentage of neurons expressing neurokinin-1 receptor in the cytosol of L6 DRGs from wild-type or Na(v)1.8 knock-out mice. These findings suggest that Na(v)1.8 is involved in the regulation of the release and synthesis of SP in the DRG neurons of wild-type mice. PMID:18845912

  2. Mouse DRG Cell Line with Properties of Nociceptors.

    PubMed

    Doran, Ciara; Chetrit, Jonathan; Holley, Matthew C; Grundy, David; Nassar, Mohammed A

    2015-01-01

    In vitro cell lines from DRG neurons aid drug discovery because they can be used for early stage, high-throughput screens for drugs targeting pain pathways, with minimal dependence on animals. We have established a conditionally immortal DRG cell line from the Immortomouse. Using immunocytochemistry, RT-PCR and calcium microfluorimetry, we demonstrate that the cell line MED17.11 expresses markers of cells committed to the sensory neuron lineage. Within a few hours under differentiating conditions, MED17.11 cells extend processes and following seven days of differentiation, express markers of more mature DRG neurons, such as NaV1.7 and Piezo2. However, at least at this time-point, the nociceptive marker NaV1.8 is not expressed, but the cells respond to compounds known to excite nociceptors, including the TRPV1 agonist capsaicin, the purinergic receptor agonist ATP and the voltage gated sodium channel agonist, veratridine. Robust calcium transients are observed in the presence of the inflammatory mediators bradykinin, histamine and norepinephrine. MED17.11 cells have the potential to replace or reduce the use of primary DRG culture in sensory, pain and developmental research by providing a simple model to study acute nociception, neurite outgrowth and the developmental specification of DRG neurons. PMID:26053673

  3. Mouse DRG Cell Line with Properties of Nociceptors

    PubMed Central

    Doran, Ciara; Chetrit, Jonathan; Holley, Matthew C.; Grundy, David; Nassar, Mohammed A.

    2015-01-01

    In vitro cell lines from DRG neurons aid drug discovery because they can be used for early stage, high-throughput screens for drugs targeting pain pathways, with minimal dependence on animals. We have established a conditionally immortal DRG cell line from the Immortomouse. Using immunocytochemistry, RT-PCR and calcium microfluorimetry, we demonstrate that the cell line MED17.11 expresses markers of cells committed to the sensory neuron lineage. Within a few hours under differentiating conditions, MED17.11 cells extend processes and following seven days of differentiation, express markers of more mature DRG neurons, such as NaV1.7 and Piezo2. However, at least at this time-point, the nociceptive marker NaV1.8 is not expressed, but the cells respond to compounds known to excite nociceptors, including the TRPV1 agonist capsaicin, the purinergic receptor agonist ATP and the voltage gated sodium channel agonist, veratridine. Robust calcium transients are observed in the presence of the inflammatory mediators bradykinin, histamine and norepinephrine. MED17.11 cells have the potential to replace or reduce the use of primary DRG culture in sensory, pain and developmental research by providing a simple model to study acute nociception, neurite outgrowth and the developmental specification of DRG neurons. PMID:26053673

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

    PubMed

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

    2014-09-26

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

  5. Experience-dependent plasticity of mature adult-born neurons.

    PubMed

    Livneh, Yoav; Mizrahi, Adi

    2012-01-01

    The adult olfactory bulb and hippocampus are continuously supplied with newborn neurons that are thought to possess a capacity for plasticity only at a young neuronal age, mainly during the early stages of integration into the network. We find that the two main types of adult-born neurons in the mouse olfactory bulb undergo experience-dependent plasticity long after maturation and integration, as evidenced by stabilization of synaptic turnover rates. Thus, the potential time window for plasticity of adult-born neurons extends well into maturity. PMID:22081159

  6. 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

  7. Changes in expression of two tetrodotoxin-resistant sodium channels and their currents in dorsal root ganglion neurons after sciatic nerve injury but not rhizotomy.

    PubMed

    Sleeper, A A; Cummins, T R; Dib-Hajj, S D; Hormuzdiar, W; Tyrrell, L; Waxman, S G; Black, J A

    2000-10-01

    Two TTX-resistant sodium channels, SNS and NaN, are preferentially expressed in c-type dorsal root ganglion (DRG) neurons and have been shown recently to have distinct electrophysiological signatures, SNS producing a slowly inactivating and NaN producing a persistent sodium current with a relatively hyperpolarized voltage-dependence. An attenuation of SNS and NaN transcripts has been demonstrated in small DRG neurons after transection of the sciatic nerve. However, it is not known whether changes in the currents associated with SNS and NaN or in the expression of SNS and NaN channel protein occur after axotomy of the peripheral projections of DRG neurons or whether similar changes occur after transection of the central (dorsal root) projections of DRG neurons. Peripheral and central projections of L4/5 DRG neurons in adult rats were axotomized by transection of the sciatic nerve and the L4 and L5 dorsal roots, respectively. DRG neurons were examined using immunocytochemical and patch-clamp methods 9-12 d after sciatic nerve or dorsal root lesion. Levels of SNS and NaN protein in the two types of injuries were paralleled by their respective TTX-resistant currents. There was a significant decrease in SNS and NaN signal intensity in small DRG neurons after peripheral, but not central, axotomy compared with control neurons. Likewise, there was a significant reduction in slowly inactivating and persistent TTX-resistant currents in these neurons after peripheral, but not central, axotomy compared with control neurons. These results indicate that peripheral, but not central, axotomy results in a reduction in expression of functional SNS and NaN channels in c-type DRG neurons and suggest a basis for the altered electrical properties that are observed after peripheral nerve injury. PMID:11007885

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

    PubMed

    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 (I(Na(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 I(NaV(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 I(Na(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

  9. 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

  10. Dendritic development of newly generated neurons in the adult brain.

    PubMed

    Ribak, Charles E; Shapiro, Lee A

    2007-10-01

    Ramon y Cajal described the fundamental morphology of the dendritic and axonal growth cones of neurons during development. However, technical limitations at the time prevented him from describing such growth cones from newborn neurons in the adult brain. The phenomenon of adult neurogenesis is briefly reviewed, and the structural description of dendritic and axonal outgrowth for these newly generated neurons in the adult brain is discussed. Axonal outgrowth into the hilus and CA3 region of the hippocampus occurs later than the outgrowth of dendrites into the molecular layer, and the ultrastructural analysis of axonal outgrowth has yet to be completed. In contrast, growth cones on dendrites from newborn neurons in the adult dentate gyrus have been described and this observation suggests that dendrites in adult brains grow in a similar way to those found in immature brains. However, dendrites in adult brains have to navigate through a denser neuropil and a more complex cell layer. Therefore, some aspects of dendritic outgrowth of neurons born in the adult dentate gyrus are different as compared to that found in development. These differences include the radial process of radial glial cells acting as a lattice to guide apical dendritic growth through the granule cell layer and a much thinner dendrite to grow through the neuropil of the molecular layer. Therefore, similarities and differences exist for dendritic outgrowth from newborn neurons in the developing and adult brain.

  11. Epidermal growth factor receptor in adult human dorsal root ganglia.

    PubMed

    Huerta, J J; Diaz-Trelles, R; Naves, F J; Llamosas, M M; Del Valle, M E; Vega, J A

    1996-09-01

    Transforming growth factor-alpha (TGFalpha) enhances neuronal survival and neurite outgrowth in cultured dorsal root ganglia (DRG) sensory neurons. It binds a membrane protein, denominated epidermal growth factor receptor (EGFr). EGFr has been localized in developing and adult human DRG. However, it remains to be elucidated whether all DRG neurons express EGFr or whether differences exist among neuronal subtypes. This study was undertaken to investigate these topics in adult human DRG using immunoblotting, and combined immunohistochemistry and image analysis techniques. A mouse monoclonal antibody (clone F4) mapping within the intracytoplasmic domain of EGFr was used. Immunoblotting revealed two main proteins with estimated molecular masses of approximately/equal to 65 kDa and 170 kDa, and thus consistent with the full-length EGFr. Additional protein bands were also encountered. Light immunohistochemistry revealed specific immunoreactivity (IR) for EGFr-like proteins in most (86%) primary sensory neurons, the intensity of immunostaining being stronger in the small- and intermediate-sized ones. Furthermore, EGFr-like IR was also observed in the satellite glial cells of the ganglia as well as in the intraganglionic and dorsal root Schwann cells. Taken together, our findings demonstrate that EGFr, and other related proteins containing the epitope labeled with the antibody F4, are responsible for the EGFr IR reported in DRG. Furthermore, we demonstrated heterogeneity in the expression of EGFr-like IR in adult human primary sensory neurons, which suggests different responsiveness to their ligands.

  12. 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.

  13. Neuronal fate determinants of adult olfactory bulb neurogenesis.

    PubMed

    Hack, Michael A; Saghatelyan, Armen; de Chevigny, Antoine; Pfeifer, Alexander; Ashery-Padan, Ruth; Lledo, Pierre-Marie; Götz, Magdalena

    2005-07-01

    Adult neurogenesis in mammals is restricted to two small regions, including the olfactory bulb, where GABAergic and dopaminergic interneurons are newly generated throughout the entire lifespan. However, the mechanisms directing them towards a specific neuronal phenotype are not yet understood. Here, we demonstrate the dual role of the transcription factor Pax6 in generating neuronal progenitors and also in directing them towards a dopaminergic periglomerular phenotype in adult mice. We present further evidence that dopaminergic periglomerular neurons originate in a distinct niche, the rostral migratory stream, and are fewer derived from precursors in the zone lining the ventricle. This regionalization of the adult precursor cells is further supported by the restricted expression of the transcription factor Olig2, which specifies transit-amplifying precursor fate and opposes the neurogenic role of Pax6. Together, these data explain both extrinsic and intrinsic mechanisms controlling neuronal identity in adult neurogenesis.

  14. 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

  15. Releasing the peri-neuronal net to patch-clamp neurons in adult CNS.

    PubMed

    Morales, Ezequiel; Fernandez, Fernando R; Sinclair, Suzanne; Molineux, Michael L; Mehaffey, W Hamish; Turner, Ray W

    2004-05-01

    The extracellular matrix of adult neural tissue contains chondroitin sulphated proteogylcans that form a dense peri-neuronal net surrounding the cell body and proximal dendrites of many neuronal classes. Development of the peri-neuronal net beyond approximately postnatal day 17 obscures visualization and often access by patch electrodes to neuronal membranes with the result that patch clamp recordings are most readily obtained from early postnatal animals. We describe a technique in which the surface tension of a sucrose-based medium promotes partial dissociation of thin tissue slices from adult tissue. Surface tension spreads the tissue and loosens the peri-neuronal net from neuronal membranes within minutes and in the absence of proteolytic enzymes. Furthermore, the extent of dissociation can be controlled so as to maintain the overall slice structure and allow identification of specific cell classes. Excellent structural preservation of neurons and dendrites can be obtained and full access by patch electrodes made possible for current- or voltage-clamp recordings in tissue well beyond the development of peri-neuronal nets. We demonstrate the feasibility of using this approach through patch recordings from neurons in the brainstem and cerebellum of adult gymnotiform fish and in deep cerebellar nuclei of rats as old as 6 months.

  16. 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

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

    PubMed Central

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

    2008-01-01

    SUMMARY We recorded Ca2+ current and intracellular Ca2+ ([Ca2+]i) in isolated adult rat dorsal root ganglion (DRG) neurons at 20 and 30 °C. In neurons bathed in tetraethylammonium and dialyzed with cesium, warming reduced resting average [Ca2+]i from 87 to 49 nM and the time constant of the decay of [Ca2+]i transients (τr) from 1.3 s to 0.99 s (Q10 = 1.4). The Buffer Index, the ratio between Ca2+ influx and Δ[Ca2+]i (∫ICa·dt/Δ[Ca2+]i), increased 2- to 3-fold 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 (500 nM) increased resting [Ca2+]i at 30 °C. 10 mM intracellular sodium prolonged the recovery of [Ca2+]i transients to 10 – 40 s. This effect was reversed by an inhibitor of mitochondrial Na+/Ca2+-exchange (CGP 37157, 10 μM). 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 °C. PMID:17716728

  18. Engrailed expression in subsets of adult Drosophila sensory neurons

    PubMed Central

    Blagburn, Jonathan M.

    2008-01-01

    Engrailed (En) has an important role in neuronal development in vertebrates and invertebrates. In adult Drosophila, although En expression persists throughout adulthood, a detailed description of its expression in sensory neurons has not been made. In this study, en-GAL4 was used to drive UAS-CD8::GFP expression and the projections of sensory neurons were examined with confocal microscopy. En protein expression was confirmed using immunocytochemistry. In the antenna, En is present in subsets of Johnston’s organ neurons and of olfactory neurons. En-driven GFP is expressed in axons projecting to 18 identifed olfactory glomeruli, originating from basiconic, trichoid and coeloconic sensilla. In most cases both neurons of a sensillum express En. En expression overlaps with that of Acj6, another transcription factor. En-driven GFP is also expressed in a subset of maxillary palp olfactory neurons and in all mechanosensory and gustatory sensilla in the posterior compartment of the labial palps. In the legs and halteres, en-driven GFP is expressed in only a subset of the sensory neurons of different modalities that arise in the posterior compartment. Finally, en-driven GFP is expressed in a single multidendritic sensory neuron in each abdominal segment. PMID:18597129

  19. Neurons in the White Matter of the Adult Human Neocortex

    PubMed Central

    Suárez-Solá, M. Luisa; González-Delgado, Francisco J.; Pueyo-Morlans, Mercedes; Medina-Bolívar, O. Carolina; Hernández-Acosta, N. Carolina; González-Gómez, Miriam; Meyer, Gundela

    2009-01-01

    The white matter (WM) of the adult human neocortex contains the so-called “interstitial neurons”. They are most numerous in the superficial WM underlying the cortical gyri, and decrease in density toward the deep WM. They are morphologically heterogeneous. A subgroup of interstitial neurons display pyramidal-cell like morphologies, characterized by a polarized dendritic tree with a dominant apical dendrite, and covered with a variable number of dendritic spines. In addition, a large contingent of interstitial neurons can be classified as interneurons based on their neurochemical profile as well as on morphological criteria. WM- interneurons have multipolar or bipolar shapes and express GABA and a variety of other neuronal markers, such as calbindin and calretinin, the extracellular matrix protein reelin, or neuropeptide Y, somatostatin, and nitric oxide synthase. The heterogeneity of interstitial neurons may be relevant for the pathogenesis of Alzheimer disease and schizophrenia. Interstitial neurons are most prominent in human brain, and only rudimentary in the brain of non-primate mammals. These evolutionary differences have precluded adequate experimental work on this cell population, which is usually considered as a relict of the subplate, a transient compartment proper of development and without a known function in the adult brain. The primate-specific prominence of the subplate in late fetal stages points to an important role in the establishment of interstitial neurons. Neurons in the adult WM may be actively involved in coordinating inter-areal connectivity and regulation of blood flow. Further studies in primates will be needed to elucidate the developmental history, adult components and activities of this large neuronal system. PMID:19543540

  20. Self-regulation of adult thalamocortical neurons.

    PubMed

    Kasten, Michael R; Anderson, Matthew P

    2015-07-01

    The thalamus acts as a conduit for sensory and other information traveling to the cortex. In response to continuous sensory stimulation in vivo, the firing rate of thalamocortical neurons initially increases, but then within a minute firing rate decreases and T-type Ca(2+) channel-dependent action potential burst firing emerges. While neuromodulatory systems could play a role in this inhibitory response, we instead report a novel and cell-autonomous inhibitory mechanism intrinsic to the thalamic relay neuron. Direct intracellular stimulation of thalamocortical neuron firing initially triggered a continuous and high rate of action potential discharge, but within a minute membrane potential (Vm) was hyperpolarized and firing rate to the same stimulus was decreased. This self-inhibition was observed across a wide variety of thalamic nuclei, and in a subset firing mode switched from tonic to bursting. The self-inhibition resisted blockers of intracellular Ca(2+) signaling, Na(+)-K(+)-ATPases, and G protein-regulated inward rectifier (GIRK) channels as implicated in other neuron subtypes, but instead was in part inhibited by an ATP-sensitive K(+) channel blocker. The results identify a new homeostatic mechanism within the thalamus capable of gating excitatory signals at the single-cell level. PMID:25948871

  1. New neurons in the adult striatum: from rodents to humans

    PubMed Central

    Inta, Dragos; Cameron, Heather A.; Gass, Peter

    2015-01-01

    Most neurons are generated during development and are not replaced during adulthood, even if they are lost to injury or disease. It is firmly established, however, that new neurons are generated in the dentate gyrus of the hippocampus of virtually all adult mammals, including humans [1]. Many questions still remain, however, regarding adult neurogenesis in other brain regions and particularly in humans, where standard birthdating methods are not generally feasible. Exciting recent evidence indicates that calretinin-expressing interneurons are added to the adult human striatum at a substantial rate [2]. The role of new neurons is unknown, but studies in rodents will be able to further elucidate their identity and origin and then begin to understand their regulation and function. PMID:26298770

  2. 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.

  3. Despite Differences in Cytosolic Calcium Regulation, Lidocaine Toxicity Is Similar in Adult and Neonatal Rat Dorsal Root Ganglia in Vitro

    PubMed Central

    Doan, Lisa V.; Eydlin, Olga; Piskoun, Boris; Kline, Richard P; Recio-Pinto, Esperanza; Rosenberg, Andrew D; Blanck, Thomas JJ; Xu, Fang

    2013-01-01

    Background Neuraxial local anesthetics may have neurological complications thought to be due to neurotoxicity. A primary site of action for local anesthetics is the dorsal root ganglia (DRG) neuron. Physiologic differences have been noted between young and adult DRG neurons; hence, we examined whether there were differences in lidocaine-induced changes in calcium and lidocaine toxicity in neonatal and adult rat DRG neurons. Methods DRG neurons were cultured from postnatal day 7 (P7) and adult rats. Lidocaine-induced changes in cytosolic calcium were examined with the calcium indicator Fluo-4. Cells were incubated with varying concentrations of lidocaine and examined for viability using calcein AM and ethidium homodimer-1 staining. Live imaging of caspase-3/7 activation was performed after incubation with lidocaine. Results The mean KCl-induced calcium transient was greater in P7 neurons (p < 0.05), and lidocaine significantly inhibited KCl-induced calcium responses in both ages (p < 0.05). Frequency distribution histograms of KCl-evoked calcium increases were more heterogeneous in P7 than in adult neurons. With lidocaine, KCl-induced calcium transients in both ages became more homogeneous but remained different between the groups. Interestingly cell viability was decreased by lidocaine in a dose-dependent manner similarly in both ages. Lidocaine treatment also activated caspase-3/7 in a dose- and time-dependent manner similarly in both ages. Conclusions Despite physiological differences in P7 and adult DRG neurons, lidocaine cytotoxicity is similar in P7 and adult DRG neurons in vitro. Differences in lidocaine- and KCl-evoked calcium responses suggest the similarity in lidocaine cytotoxicity involves other actions in addition to lidocaine-evoked effects on cytosolic calcium responses. PMID:23851347

  4. 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

  5. NGF has opposing effects on Na+ channel III and SNS gene expression in spinal sensory neurons.

    PubMed

    Black, J A; Langworthy, K; Hinson, A W; Dib-Hajj, S D; Waxman, S G

    1997-07-01

    Following sciatic nerve transection, the expression of sodium channel III (alpha-III) transcripts increases and SNS (alpha-SNS) transcripts decreases in small (< 25 microns diameter) dorsal root ganglion (DRG) neurons, which may reflect an interruption of retrograde transport of peripherally derived factor(s) involved in the regulation of these channels. To test the hypothesis that the neurotrophin nerve growth factor (NGF), which is abundant in peripheral targets, participates in the modulation of the expression of these sodium channel transcripts, we examined the hybridization signal of alpha-SNS and alpha-III mRNAs in small DRG neurons from adult rats that had been dissociated and maintained for 7 days in the absence or presence of exogenous NGF. Neurons maintained in control (no added NGF) cultures showed changes in alpha-III and alpha-SNS hybridization signal similar to those induced by axotomy, with increased alpha-III mRNA levels and decreased alpha-SNS mRNA levels, compared with those observed in small DRG neurons at 1 day in vitro. The addition of exogenous NGF to DRG cultures attenuated these alterations in transcript levels, decreasing alpha-III mRNA and increasing alpha-SNS mRNA expression. These results suggest that NGF participates in the regulation of membrane excitability in small DRG neurons by pathways that include opposing effects on different sodium channel genes. PMID:9243635

  6. 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

  7. PTEN Deletion Enhances the Regenerative Ability of Adult Corticospinal Neurons

    PubMed Central

    Liu, Kai; Lu, Yi; Lee, Jae K.; Samara, Ramsey; Willenberg, Rafer; Sears-Kraxberger, Ilse; Tedeschi, Andrea; Park, Kevin Kyungsuk; Jin, Duo; Cai, Bin; Xu, Bengang; Connolly, Lauren; Steward, Oswald; Zheng, Binhai; He, Zhigang

    2010-01-01

    Despite the essential role of the corticospinal tract (CST) in controlling voluntary movements, successful regeneration of large numbers of injured CST axons beyond a spinal cord lesion has never been achieved. Here we demonstrate a critical involvement of PTEN/mTOR in controlling the regenerative capacity of mouse corticospinal neurons. Upon the completion of development, the regrowth potential of CST axons lost and this is accompanied by a down-regulation of mTOR activity in corticospinal neurons. Axonal injury further diminishes neuronal mTOR activity in these neurons. Forced up-regulation of mTOR activity in corticospinal neurons by conditional deletion of PTEN, a negative regulator of mTOR, enhances compensatory sprouting of uninjured CST axons and even more strikingly, enables successful regeneration of a cohort of injured CST axons past a spinal cord lesion. Furthermore, these regenerating CST axons possess the ability to reform synapses in spinal segments distal to the injury. Thus, modulating neuronal intrinsic PTEN/mTOR activity represents a potential therapeutic strategy for promoting axon regeneration and functional repair after adult spinal cord injury. PMID:20694004

  8. 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

  9. 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

  10. Regeneration of supraspinal projection neurons in the adult goldfish.

    PubMed

    Sharma, S C; Jadhao, A G; Rao, P D

    1993-08-27

    Regeneration of descending supraspinal projections were identified in adult goldfish following administration of HRP to different levels of the spinal cord. While in the untreated normal fish 17 nuclei were shown to project into the spinal cord, only 11 of them seem to have participated in the process of regeneration. The nuclei whose axons regenerated include the nucleus ventromedialis (NVMD), nucleus of the median longitudinal fasciculus (NMLF), nucleus reticularis superior (NRS), nucleus reticularis medialis (NRM), nucleus reticularis inferior (NRI), anterior octaval nucleus (AON), magnocellular octaval nucleus (MON), descending octaval nucleus (DON) and certain neurons of the facial lobe. The neurons of the magnocellular preoptic nucleus (NPO), raphe nucleus (NR), Mauthner cell (MC), posterior octaval nucleus (PON) and somata located adjacent to the descending trigeminal tract were not labeled. The nuclei that apparently participated in the regeneration process were significantly larger in size than the corresponding cell bodies in the untreated normal fish.

  11. 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

  12. Environmental impact on direct neuronal reprogramming in vivo in the adult brain.

    PubMed

    Grande, Andrew; Sumiyoshi, Kyoko; 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 the 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 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 Neurogenin2 differently and instruct new neurons to exhibit distinct molecular phenotypes. Moreover, ischaemic insult differentially affects differentiation of new neurons in these regions. These results demonstrate strong environmental impact on direct neuronal reprogramming in vivo.

  13. In vivo differential susceptibility of sensory neurons to rabies virus infection.

    PubMed

    Velandia-Romero, Myriam L; Castellanos, Jaime E; Martínez-Gutiérrez, Marlén

    2013-08-20

    There is controversy with regard to the entry pathway of the rabies virus (RABV) into the central nervous system (CNS). Some authors have suggested that the virus inoculated at the periphery is captured and transported to CNS only by motor neurons; however, it has been reported that dorsal root ganglia (DRG) sensory neurons capture and transport the virus to the spinal cord (SC) and then to the brain. It is probable that preferences for one pathway or another depend on the site of inoculation and the post-infection time. Therefore, in the present study, we evaluated different vertebral segments and post-infection times, along with the location, number, and subpopulation of sensory neurons susceptible to infection after inoculating RABV in the footpads of adult mice. It was noted that the virus inoculated in the footpad preferentially entered the CNS through the large-sized DRG sensory neurons, while infection of the motor neurons occurred later. Further, it was found that the virus was dispersed in spinal cord trans-synaptically through the interneurons, arriving at both sensory neurons and contralateral motor neurons. In conclusion, we observed that RABV inoculated in the plantar footpad is captured preferentially by large sensory neurons and is transported to the DRG, where it replicates and is spread to the SC using transynaptic jumps, infecting sensory and motor neurons at the same level before ascending to the brain.

  14. Recovery of viscerosensory innervation from the dorsal root ganglia of the adult rat following capsaicin-induced injury.

    PubMed

    Gallaher, Zachary R; Larios, Rose Marie; Ryu, Vitaly; Sprunger, Leslie K; Czaja, Krzysztof

    2010-09-01

    Capsaicin is a neurotoxin selective for C- and Adelta-type neurons. Systemic treatment with capsaicin is known to reduce this subpopulation in the dorsal root ganglia (DRG) of neonatal rats. To better understand the effects of capsaicin on adult afferent fibers, we examined DRG neurons retrogradely labeled by an i.p. injection of Fast Blue (FB) administered 3, 30, or 60 days after systemic capsaicin treatment (125 mg/kg i.p.). FB labeling in the 12th and 13th thoracic DRG was dramatically reduced 3 and 30 days post capsaicin (50% and 35% of control, respectively). However, the number of retrogradely labeled neurons rose to 65% of control by 60 days post capsaicin. In addition to FB labeling, we quantified the immunoreactivity of NR1, the obligatory N-methyl-D-aspartate receptor subunit, and Na(v)1.8, a DRG-specific sodium channel, in FB-labeled neurons as well as mRNA levels for both proteins in the 5th and 6th lumbar DRG. NR1 immunoreactivity and mRNA expression followed a pattern of early reduction and subsequent partial restoration similar to FB labeling. Na(v)1.8 immunoreactivity and mRNA expression dropped to approximately 50% of control at 3 days post capsaicin but completely recovered by 60 days. These data strongly support the conclusion that restoration of spinal afferent projections and signaling occurs in adult rats following capsaicin-induced damage. PMID:20593356

  15. 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.

  16. 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.

  17. 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

  18. Neuronal replacement from endogenous precursors in the adult brain after stroke.

    PubMed

    Arvidsson, Andreas; Collin, Tove; Kirik, Deniz; Kokaia, Zaal; Lindvall, Olle

    2002-09-01

    In the adult brain, new neurons are continuously generated in the subventricular zone and dentate gyrus, but it is unknown whether these neurons can replace those lost following damage or disease. Here we show that stroke, caused by transient middle cerebral artery occlusion in adult rats, leads to a marked increase of cell proliferation in the subventricular zone. Stroke-generated new neurons, as well as neuroblasts probably already formed before the insult, migrate into the severely damaged area of the striatum, where they express markers of developing and mature, striatal medium-sized spiny neurons. Thus, stroke induces differentiation of new neurons into the phenotype of most of the neurons destroyed by the ischemic lesion. Here we show that the adult brain has the capacity for self-repair after insults causing extensive neuronal death. If the new neurons are functional and their formation can be stimulated, a novel therapeutic strategy might be developed for stroke in humans. PMID:12161747

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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...-Term Care Hospitals § 412.515 LTC-DRG weighting factors. For each LTC-DRG, CMS assigns an...

  7. 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

  8. A critical period for experience-dependent remodeling of adult-born neuron connectivity.

    PubMed

    Bergami, Matteo; Masserdotti, Giacomo; Temprana, Silvio G; Motori, Elisa; Eriksson, Therese M; Göbel, Jana; Yang, Sung Min; Conzelmann, Karl-Klaus; Schinder, Alejandro F; Götz, Magdalena; Berninger, Benedikt

    2015-02-18

    Neurogenesis in the dentate gyrus (DG) of the adult hippocampus is a process regulated by experience. To understand whether experience also modifies the connectivity of new neurons, we systematically investigated changes in their innervation following environmental enrichment (EE). We found that EE exposure between 2-6 weeks following neuron birth, rather than merely increasing the number of new neurons, profoundly affected their pattern of monosynaptic inputs. Both local innervation by interneurons and to even greater degree long-distance innervation by cortical neurons were markedly enhanced. Furthermore, following EE, new neurons received inputs from CA3 and CA1 inhibitory neurons that were rarely observed under control conditions. While EE-induced changes in inhibitory innervation were largely transient, cortical innervation remained increased after returning animals to control conditions. Our findings demonstrate an unprecedented experience-dependent reorganization of connections impinging onto adult-born neurons, which is likely to have important impact on their contribution to hippocampal information processing.

  9. 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

  10. Regeneration of central cholinergic neurones in the adult rat brain.

    PubMed

    Svendgaard, N A; Björklund, A; Stenevi, U

    1976-01-30

    The regrowth of lesioned central acetylcholinesterase (AChE)-positive axons in the adult rat was studied in irides implanted to two different brain sites: in the caudal diencephalon and hippocampus, and in the hippocampal fimbria. At both implantation sites the cholinergic septo-hippocampal pathways were transected. At 2-4 weeks after lesion, newly formed, probably sprouting fibres could be followed in abundance from the lesioned proximal axon stumps into the iris transplant. Growth of newly formed AChE-positive fibres into the transplant was also observed from lesioned axons in the anterior thalamus, and to a minor extent also from the dorsal and ventral tegmental AChE-positive pathways and the habenulo-interpeduncular tract. The regrowth process of the sprouting AChE-positive, presumed cholinergic fibres into the iris target was studied in further detail in whole-mount preparations of the transplants. For this purpose the irides were removed from the brain, unfolded, spread out on microscope slides, and then stained for AChE. During the first 2-4 weeks after transplantation the sprouting central fibres grew out over large areas of the iris. The new fibres branched profusely into a terminal plexus that covered maximally about half of the iris surface, and in some areas the patterning of the regenerated central fibres mimicked closely that of the normal autonomic cholinergic innervation of the iris. In one series of experiments the AChE-staining was combined with fluorescence histochemical visualization of regenerated adrenergic fibres in the same specimens. In many areas there was a striking congruence in the distributional patterns of the regenerated central cholinergic and adrenergic fibres in the transplant. This indicates that - as in the normal iris - the sprouting cholinergic axons (primarily originating in the lesioned septo-hippocampal pathways) and adrenergic axons (primarily originating in the lesioned axons of the locus neurones) regenerate together

  11. Neuron regeneration reverses 3-acetylpyridine-induced cell loss in the cerebral cortex of adult lizards.

    PubMed

    Font, E; García-Verdugo, J M; Alcántara, S; López-García, C

    1991-06-14

    Systemic administration of the neurotoxin 3-acetylpyridine to adult lizards results in extensive loss of neurons in the medial cerebral cortex, other brain areas remaining largely unaffected. After the neurotoxic trauma, new cells are produced by mitotic division of cells in the ventricular wall. The new cells migrate along radial glial fibers and replace lost neurons in the medial cortex. Electron microscopic examination of cells labeled with [3H]thymidine confirms that the newly generated cells are neurons. Thus, neuron regeneration can occur in the cerebral cortex of adult lizards.

  12. Migration of neuronal precursors from the telencephalic ventricular zone into the olfactory bulb in adult zebrafish.

    PubMed

    Kishimoto, Norihito; Alfaro-Cervello, Clara; Shimizu, Kohei; Asakawa, Kazuhide; Urasaki, Akihiro; Nonaka, Shigenori; Kawakami, Koichi; Garcia-Verdugo, Jose Manuel; Sawamoto, Kazunobu

    2011-12-01

    In the brain of adult mammals, neuronal precursors are generated in the subventricular zone in the lateral wall of the lateral ventricles and migrate into the olfactory bulbs (OBs) through a well-studied route called the rostral migratory stream (RMS). Recent studies have revealed that a comparable neural stem cell niche is widely conserved at the ventricular wall of adult vertebrates. However, little is known about the migration route of neuronal precursors in nonmammalian adult brains. Here, we show that, in the adult zebrafish, a cluster of neuronal precursors generated in the telencephalic ventricular zone migrates into the OB via a route equivalent to the mammalian RMS. Unlike the mammalian RMS, these neuronal precursors are not surrounded by glial tubes, although radial glial cells with a single cilium lined the telencephalic ventricular wall, much as in embryonic and neonatal mammals. To observe the migrating neuronal precursors in living brain tissue, we established a brain hemisphere culture using a zebrafish line carrying a GFP transgene driven by the neurogenin1 (ngn1) promoter. In these fish, GFP was observed in the neuronal precursors migrating in the RMS, some of which were aligned with blood vessels. Numerous ngn1:gfp-positive cells were observed migrating tangentially in the RMS-like route medial to the OB. Taken together, our results suggest that the RMS in the adult zebrafish telencephalon is a functional migratory pathway. This is the first evidence for the tangential migration of neuronal precursors in a nonmammalian adult telencephalon.

  13. A hindbrain segmental scaffold specifying neuronal location in the adult goldfish, Carassius auratus.

    PubMed

    Gilland, E; Straka, H; Wong, T W; Baker, R; Zottoli, S J

    2014-07-01

    The vertebrate hindbrain develops as a series of well-defined neuroepithelial segments or rhombomeres. While rhombomeres are visible in all vertebrate embryos, generally there is not any visible segmental anatomy in the brains of adults. Teleost fish are exceptional in retaining a rhombomeric pattern of reticulospinal neurons through embryonic, larval, and adult periods. We use this feature to map more precisely the segmental imprint in the reticular and motor basal hindbrain of adult goldfish. Analysis of serial sections cut in three planes and computer reconstructions of retrogradely labeled reticulospinal neurons yielded a segmental framework compatible with previous reports and more amenable to correlation with surrounding neuronal features. Cranial nerve motoneurons and octavolateral efferent neurons were aligned to the reticulospinal scaffold by mapping neurons immunopositive for choline acetyltransferase or retrogradely labeled from cranial nerve roots. The mapping corresponded well with the known ontogeny of these neurons and helps confirm the segmental territories defined by reticulospinal anatomy. Because both the reticulospinal and the motoneuronal segmental patterns persist in the hindbrain of adult goldfish, we hypothesize that a permanent "hindbrain framework" may be a general property that is retained in adult vertebrates. The establishment of a relationship between individual segments and neuronal phenotypes provides a convenient method for future studies that combine form, physiology, and function in adult vertebrates.

  14. Persistent production of neurons from adult brain stem cells during recovery after stroke.

    PubMed

    Thored, Pär; Arvidsson, Andreas; Cacci, Emanuele; Ahlenius, Henrik; Kallur, Therése; Darsalia, Vladimer; Ekdahl, Christine T; Kokaia, Zaal; Lindvall, Olle

    2006-03-01

    Neural stem cells in the subventricular zone of adult rodents produce new striatal neurons that may replace those that have died after stroke; however, the neurogenic response has been considered acute and transient, yielding only small numbers of neurons. In contrast, we show herein that striatal neuroblasts are generated without decline at least for 4 months after stroke in adult rats. Neuroblasts formed early or late after stroke either differentiate into mature neurons, which survive for several months, or die through caspase-mediated apoptosis. The directed migration of the new neurons toward the ischemic damage is regulated by stromal cell-derived factor-1alpha and its receptor CXCR4. These results show that endogenous neural stem cells continuously supply the injured adult brain with new neurons, which suggests novel self-repair strategies to improve recovery after stroke. PMID:16210404

  15. 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.

  16. 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

  17. Disrupted-In-Schizophrenia 1 regulates integration of newly generated neurons in the adult brain

    PubMed Central

    Duan, Xin; Chang, Jay H.; Ge, Shaoyu; Faulkner, Regina L.; Kim, Ju Young; Kitabatake, Yasuji; Liu, Xiao-bo; Yang, Chih-Hao; Jordan, J. Dedrick; Ma, Dengke K.; Liu, Cindy Y.; Ganesan, Sundar; Cheng, Hwai-Jong; Ming, Guo-li; Lu, Bai; Song, Hongjun

    2007-01-01

    Summary Adult neurogenesis occurs throughout life in discrete regions of the adult mammalian brain. Little is known about the mechanism governing the sequential developmental process that leads to integration of new neurons from adult neural stem cells into the existing circuitry. Here, we investigated roles of Disrupted-In-Schizophrenia 1 (DISC1), a schizophrenia susceptibility gene, in adult hippocampal neurogenesis. Unexpectedly, down regulation of DISC1 leads to accelerated neuronal integration, resulting in aberrant morphological development and mis-positioning of new dentate granule cells in a cell-autonomous fashion. Functionally, newborn neurons with DISC1 knockdown exhibit enhanced excitability and accelerated dendritic development and synapse formation. Furthermore, DISC1 cooperates with its binding partner Ndel1 in regulating adult neurogenesis. Taken together, our study identifies DISC1 as a key regulator that orchestrates the tempo of functional neuronal integration in the adult brain and demonstrates essential roles of a susceptibility gene for major mental illness in neuronal development, including adult neurogenesis. PMID:17825401

  18. 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

  19. 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

  20. 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

  1. 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

  2. A Subset of Serotonergic Neurons Evokes Hunger in Adult Drosophila.

    PubMed

    Albin, Stephanie D; Kaun, Karla R; Knapp, Jon-Michael; Chung, Phuong; Heberlein, Ulrike; Simpson, Julie H

    2015-09-21

    Hunger is a complex motivational state that drives multiple behaviors. The sensation of hunger is caused by an imbalance between energy intake and expenditure. One immediate response to hunger is increased food consumption. Hunger also modulates behaviors related to food seeking such as increased locomotion and enhanced sensory sensitivity in both insects and vertebrates. In addition, hunger can promote the expression of food-associated memory. Although progress is being made, how hunger is represented in the brain and how it coordinates these behavioral responses is not fully understood in any system. Here, we use Drosophila melanogaster to identify neurons encoding hunger. We found a small group of neurons that, when activated, induced a fed fly to eat as though it were starved, suggesting that these neurons are downstream of the metabolic regulation of hunger. Artificially activating these neurons also promotes appetitive memory performance in sated flies, indicating that these neurons are not simply feeding command neurons but likely play a more general role in encoding hunger. We determined that the neurons relevant for the feeding effect are serotonergic and project broadly within the brain, suggesting a possible mechanism for how various responses to hunger are coordinated. These findings extend our understanding of the neural circuitry that drives feeding and enable future exploration of how state influences neural activity within this circuit.

  3. Pre-existing astrocytes form functional perisynaptic processes on neurons generated in the adult hippocampus.

    PubMed

    Krzisch, Marine; Temprana, Silvio G; Mongiat, Lucas A; Armida, Jan; Schmutz, Valentin; Virtanen, Mari A; Kocher-Braissant, Jacqueline; Kraftsik, Rudolf; Vutskits, Laszlo; Conzelmann, Karl-Klaus; Bergami, Matteo; Gage, Fred H; Schinder, Alejandro F; Toni, Nicolas

    2015-07-01

    The adult dentate gyrus produces new neurons that morphologically and functionally integrate into the hippocampal network. In the adult brain, most excitatory synapses are ensheathed by astrocytic perisynaptic processes that regulate synaptic structure and function. However, these processes are formed during embryonic or early postnatal development and it is unknown whether astrocytes can also ensheathe synapses of neurons born during adulthood and, if so, whether they play a role in their synaptic transmission. Here, we used a combination of serial-section immuno-electron microscopy, confocal microscopy, and electrophysiology to examine the formation of perisynaptic processes on adult-born neurons. We found that the afferent and efferent synapses of newborn neurons are ensheathed by astrocytic processes, irrespective of the age of the neurons or the size of their synapses. The quantification of gliogenesis and the distribution of astrocytic processes on synapses formed by adult-born neurons suggest that the majority of these processes are recruited from pre-existing astrocytes. Furthermore, the inhibition of astrocytic glutamate re-uptake significantly reduced postsynaptic currents and increased paired-pulse facilitation in adult-born neurons, suggesting that perisynaptic processes modulate synaptic transmission on these cells. Finally, some processes were found intercalated between newly formed dendritic spines and potential presynaptic partners, suggesting that they may also play a structural role in the connectivity of new spines. Together, these results indicate that pre-existing astrocytes remodel their processes to ensheathe synapses of adult-born neurons and participate to the functional and structural integration of these cells into the hippocampal network.

  4. The microtubule destabilizing protein stathmin controls the transition from dividing neuronal precursors to postmitotic neurons during adult hippocampal neurogenesis.

    PubMed

    Boekhoorn, Karin; van Dis, Vera; Goedknegt, Erika; Sobel, André; Lucassen, Paul J; Hoogenraad, Casper C

    2014-12-01

    The hippocampus is one of the two areas in the mammalian brain where adult neurogenesis occurs. Adult neurogenesis is well known to be involved in hippocampal physiological functions as well as pathophysiological conditions. Microtubules (MTs), providing intracellular transport, stability, and transmitting force, are indispensable for neurogenesis by facilitating cell division, migration, growth, and differentiation. Although there are several examples of MT-stabilizing proteins regulating different aspects of adult neurogenesis, relatively little is known about the function of MT-destabilizing proteins. Stathmin is such a MT-destabilizing protein largely restricted to the CNS, and in contrast to its developmental family members, stathmin is also expressed at significant levels in the adult brain, notably in areas involved in adult neurogenesis. Here, we show an important role for stathmin during adult neurogenesis in the subgranular zone of the mouse hippocampus. After carefully mapping stathmin expression in the adult dentate gyrus (DG), we investigated its role in hippocampal neurogenesis making use of stathmin knockout mice. Although hippocampus development appears normal in these animals, different aspects of adult neurogenesis are affected. First, the number of proliferating Ki-67+ cells is decreased in stathmin knockout mice, as well as the expression of the immature markers Nestin and PSA-NCAM. However, newborn cells that do survive express more frequently the adult marker NeuN and have a more mature morphology. Furthermore, our data suggest that migration in the DG might be affected. We propose a model in which stathmin controls the transition from neuronal precursors to early postmitotic neurons.

  5. The microtubule destabilizing protein stathmin controls the transition from dividing neuronal precursors to postmitotic neurons during adult hippocampal neurogenesis.

    PubMed

    Boekhoorn, Karin; van Dis, Vera; Goedknegt, Erika; Sobel, André; Lucassen, Paul J; Hoogenraad, Casper C

    2014-12-01

    The hippocampus is one of the two areas in the mammalian brain where adult neurogenesis occurs. Adult neurogenesis is well known to be involved in hippocampal physiological functions as well as pathophysiological conditions. Microtubules (MTs), providing intracellular transport, stability, and transmitting force, are indispensable for neurogenesis by facilitating cell division, migration, growth, and differentiation. Although there are several examples of MT-stabilizing proteins regulating different aspects of adult neurogenesis, relatively little is known about the function of MT-destabilizing proteins. Stathmin is such a MT-destabilizing protein largely restricted to the CNS, and in contrast to its developmental family members, stathmin is also expressed at significant levels in the adult brain, notably in areas involved in adult neurogenesis. Here, we show an important role for stathmin during adult neurogenesis in the subgranular zone of the mouse hippocampus. After carefully mapping stathmin expression in the adult dentate gyrus (DG), we investigated its role in hippocampal neurogenesis making use of stathmin knockout mice. Although hippocampus development appears normal in these animals, different aspects of adult neurogenesis are affected. First, the number of proliferating Ki-67+ cells is decreased in stathmin knockout mice, as well as the expression of the immature markers Nestin and PSA-NCAM. However, newborn cells that do survive express more frequently the adult marker NeuN and have a more mature morphology. Furthermore, our data suggest that migration in the DG might be affected. We propose a model in which stathmin controls the transition from neuronal precursors to early postmitotic neurons. PMID:24909416

  6. Populations of subplate and interstitial neurons in fetal and adult human telencephalon

    PubMed Central

    Judaš, Miloš; Sedmak, Goran; Pletikos, Mihovil; Jovanov-Milošević, Nataša

    2010-01-01

    In the adult human telencephalon, subcortical (gyral) white matter contains a special population of interstitial neurons considered to be surviving descendants of fetal subplate neurons [Kostovic & Rakic (1980) Cytology and the time of origin of interstitial neurons in the white matter in infant and adult human and monkey telencephalon. J Neurocytol9, 219]. We designate this population of cells as superficial (gyral) interstitial neurons and describe their morphology and distribution in the postnatal and adult human cerebrum. Human fetal subplate neurons cannot be regarded as interstitial, because the subplate zone is an essential part of the fetal cortex, the major site of synaptogenesis and the ‘waiting’ compartment for growing cortical afferents, and contains both projection neurons and interneurons with distinct input–output connectivity. However, although the subplate zone is a transient fetal structure, many subplate neurons survive postnatally as superficial (gyral) interstitial neurons. The fetal white matter is represented by the intermediate zone and well-defined deep periventricular tracts of growing axons, such as the corpus callosum, anterior commissure, internal and external capsule, and the fountainhead of the corona radiata. These tracts gradually occupy the territory of transient fetal subventricular and ventricular zones.The human fetal white matter also contains distinct populations of deep fetal interstitial neurons, which, by virtue of their location, morphology, molecular phenotypes and advanced level of dendritic maturation, remain distinct from subplate neurons and neurons in adjacent structures (e.g. basal ganglia, basal forebrain). We describe the morphological, histochemical (nicotinamide-adenine dinucleotide phosphate-diaphorase) and immunocytochemical (neuron-specific nuclear protein, microtubule-associated protein-2, calbindin, calretinin, neuropeptide Y) features of both deep fetal interstitial neurons and deep (periventricular

  7. 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

  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. 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

  10. Activating neurons by light in free-moving adult flies

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Chin; Hsiao, Po-Yen; Chu, Li-An; Lin, Yen-Yin; Fu, Chien-Chung; Chiang, Ann-Shyn

    2015-01-01

    In this presentation, we show our preliminary results which is related to neurons activation in vivo by laser. A laser scanning system was adopted to guide laser beam to an assigned fly and an assigned position. A 473-nm laser can be a heat punishment source to restrain a wild-type fly's moving area. Furthermore, neurons in optogenetics transgene flies can be triggered by the blue laser in this system.

  11. 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.

  12. Emerging restorative treatments for Parkinson's disease: manipulation and inducement of dopaminergic neurons from adult stem cells.

    PubMed

    Zhao, Junpeng; Xu, Qunyuan

    2011-06-01

    Parkinson's disease (PD) is a common neurodegenerative disease, characterized by a selective loss of midbrain Dopaminergic (DA) neurons. To address this problem, various types of stem cells that have potential to differentiate into DA neurons are being investigated as cellular therapies for PD, including cells derived from embryonic or adult donor tissue, and embryonic stem cells. These cell sources, however, have raised certain questions with regard to ethical and rejection issues. Recent progress in adult stems has further proved that the cells derived from adult tissue could be expanded and differentiated into DA precursor cells in vitro, and cell therapy with adult stem cells could produce a clear improvement for PD models. Using adult stem cells for clinic application may not only overcome the ethical problem inherent in using human fetal tissue or embryonic stem cells, but also open the possibility for autologous transplantation. The patient-specific adult stem cell is therefore a potential and prospective candidate for PD treatment.

  13. Dicer expression is essential for adult midbrain dopaminergic neuron maintenance and survival.

    PubMed

    Pang, Xueyan; Hogan, Eric M; Casserly, Alison; Gao, Guangping; Gardner, Paul D; Tapper, Andrew R

    2014-01-01

    The type III RNAse, Dicer, is responsible for the processing of microRNA (miRNA) precursors into functional miRNA molecules, non-coding RNAs that bind to and target messenger RNAs for repression. Dicer expression is essential for mouse midbrain development and dopaminergic (DAergic) neuron maintenance and survival during the early post-natal period. However, the role of Dicer in adult mouse DAergic neuron maintenance and survival is unknown. To bridge this gap in knowledge, we selectively knocked-down Dicer expression in individual DAergic midbrain areas, including the ventral tegmental area (VTA) and substantia nigra pars compacta (SNpc) via viral-mediated expression of Cre in adult floxed Dicer knock-in mice (Dicer(flox/flox)). Bilateral Dicer loss in the VTA resulted in progressive hyperactivity that was significantly reduced by the dopamine agonist, amphetamine. In contrast, decreased Dicer expression in the SNpc did not affect locomotor activity but did induce motor-learning impairment on an accelerating rotarod. Knock-down of Dicer in both midbrain regions of adult Dicer(flox/flox) mice resulted in preferential, progressive loss of DAergic neurons likely explaining motor behavior phenotypes. In addition, knock-down of Dicer in midbrain areas triggered neuronal death via apoptosis. Together, these data indicate that Dicer expression and, as a consequence, miRNA function, are essential for DAergic neuronal maintenance and survival in adult midbrain DAergic neuron brain areas.

  14. 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

  15. 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

  16. 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

  17. [Adult neuronal ceroid lipofuscinosis (Kufs disease)--a rare cause of dementia].

    PubMed

    Kozian, R; Kiszka, T; Peter, K

    1994-11-01

    Kufs' disease is a very rare type of neuronal ceroid lipofuscinosis. A case of a 52 year old man with dementia is described. The cause for patient's dementia was the adult type (Kufs' disease) of neuronal ceroid lipofuscinosis. The diagnosis based on the histopathological post mortem-examination of the brain-tissue. A brother of our patient became ill with the same symptoms and at the same age of onset. So we conclude that there is a accumulation in the family.

  18. The Timing of Differentiation of Adult Hippocampal Neurons Is Crucial for Spatial Memory

    PubMed Central

    Cinà, Irene; Aceti, Massimiliano; Micheli, Laura; Bacci, Alberto; Cestari, Vincenzo; Tirone, Felice

    2008-01-01

    Adult neurogenesis in the dentate gyrus plays a critical role in hippocampus-dependent spatial learning. It remains unknown, however, how new neurons become functionally integrated into spatial circuits and contribute to hippocampus-mediated forms of learning and memory. To investigate these issues, we used a mouse model in which the differentiation of adult-generated dentate gyrus neurons can be anticipated by conditionally expressing the pro-differentiative gene PC3 (Tis21/BTG2) in nestin-positive progenitor cells. In contrast to previous studies that affected the number of newly generated neurons, this strategy selectively changes their timing of differentiation. New, adult-generated dentate gyrus progenitors, in which the PC3 transgene was expressed, showed accelerated differentiation and significantly reduced dendritic arborization and spine density. Functionally, this genetic manipulation specifically affected different hippocampus-dependent learning and memory tasks, including contextual fear conditioning, and selectively reduced synaptic plasticity in the dentate gyrus. Morphological and functional analyses of hippocampal neurons at different stages of differentiation, following transgene activation within defined time-windows, revealed that the new, adult-generated neurons up to 3–4 weeks of age are required not only to acquire new spatial information but also to use previously consolidated memories. Thus, the correct unwinding of these key memory functions, which can be an expression of the ability of adult-generated neurons to link subsequent events in memory circuits, is critically dependent on the correct timing of the initial stages of neuron maturation and connection to existing circuits. PMID:18842068

  19. 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

  20. Neonatal colonic inflammation sensitizes voltage-gated Na(+) channels via upregulation of cystathionine β-synthetase expression in rat primary sensory neurons.

    PubMed

    Qu, Ruobing; Tao, Jingde; Wang, Yongmeng; Zhou, Youlang; Wu, Geping; Xiao, Ying; Hu, Chuang-Ying; Jiang, Xinghong; Xu, Guang-Yin

    2013-05-01

    The pathogenesis of pain in irritable bowel syndrome (IBS) is poorly understood, and treatment remains difficult. We have previously reported that colon-specific dorsal root ganglion (DRG) neurons were hyperactive in a rat model of IBS induced by neonatal colonic inflammation (NCI). This study was designed to examine plasticity of voltage-gated Na(+) channel activities and roles for the endogenous hydrogen sulfide-producing enzyme cystathionine β-synthetase (CBS) in chronic visceral hyperalgesia. Abdominal withdrawal reflex (AWR) scores were recorded in response to graded colorectal distention in adult male rats as a measure of visceral hypersensitivity. Colon-specific DRG neurons were labeled with 1,1'-dioleyl-3,3,3',3-tetramethylindocarbocyanine methanesulfonate and acutely dissociated for measuring Na(+) channel currents. Western blot analysis was employed to detect changes in expressions of voltage-gated Na(+) (Na(V)) channel subtype 1.7, Na(V)1.8, and CBS. NCI significantly increased AWR scores when compared with age-matched controls. NCI also led to an ~2.5-fold increase in Na(+) current density in colon-specific DRG neurons. Furthermore, NCI dramatically enhanced expression of Na(V)1.7, Na(V)1.8, and CBS in colon-related DRGs. CBS was colocalized with Na(V)1.7 or -1.8 in colon-specific DRG neurons. Administration of O-(carboxymethyl)hydroxylamine hemihydrochloride (AOAA), an inhibitor for CBS, remarkably suppressed Na(+) current density and reduced expression of Na(V)1.7 and Na(V)1.8. More importantly, intraperitoneal or intrathecal application of AOAA attenuated AWR scores in NCI rats in a dose-dependent manner. These data suggest that NCI enhances Na(+) channel activity of colon DRG neurons, which is most likely mediated by upregulation of CBS expression, thus identifying a potential target for treatment for chronic visceral pain in patients with IBS. PMID:23449670

  1. Organization of the histaminergic system in adult zebrafish (Danio rerio) brain: neuron number, location, and cotransmitters.

    PubMed

    Sundvik, Maria; Panula, Pertti

    2012-12-01

    Histamine is an essential factor in the ascending arousal system (AAS) during motivated behaviors. Histamine and hypocretin/orexin (hcrt) are proposed to be responsible for different aspects of arousal and wakefulness, histamine mainly for cognitive and motivated behaviors. In this study we visualized the entire histaminergic neuron population in adult male and female zebrafish brain and quantified the histaminergic neuron numbers. There were 40-45 histaminergic neurons in both male and female zebrafish brain. Further, we identified cotransmitters of histaminergic neurons in the ventrocaudal hypothalamus, i.e., around the posterior recess (PR) in adult zebrafish. Galanin, γ-aminobutyric acid (GABA), and thyrotropin-releasing hormone (TRH) were colocalized with histamine in some but not all neurons, a result that was verified by intracerebroventricular injections of colchicine into adult zebrafish. Fibers immunoreactive (ir) for galanin, GABA, TRH, or methionine-enkephalin (mENK) were dense in the ventrocaudal hypothalamus around the histaminergic neurons. In histamine-ir fibers TRH and galanin immunoreactivities were also detected in the ventral telencephalon. All these neurotransmitters are involved in maintaining the equilibrium of the sleep-wake state. Our results are in accordance with results from rats, further supporting the use of zebrafish as a tool to study molecular mechanisms underlying complex behaviors.

  2. 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

  3. 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

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

    PubMed

    Respondek, Michalina; Buszman, Ewa

    2015-12-31

    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.

  5. Area-specific migration and recruitment of new neurons in the adult songbird brain.

    PubMed

    Vellema, Michiel; van der Linden, Annemie; Gahr, Manfred

    2010-05-01

    Neuron recruitment has been implicated in morphological and functional plasticity in the adult brain. Whereas mammals restrict neuron recruitment specifically to two regions of known plasticity, the hippocampus and olfactory bulb, newborn neurons are found throughout the forebrain of adult songbirds. In order to study the area-specificity of the widespread proliferation and recruitment in the songbird brain, six adult male canaries received repetitive intraperitoneal injections of the mitotic marker BrdU (5-bromo-2-deoxyuridine) and were sacrificed after 24 hours to study proliferation or after 38 days to study recruitment. Migration and incorporation of new neurons was apparent throughout many but not all parts of the canary forebrain and was quantitatively related to mitotic levels in the most closely associated proliferative zones. Surprisingly, some areas of the vocal control system sensitive to plastic changes, such as nucleus higher vocal center (HVC) and area X, recruited similar numbers of new neurons as their surrounding brain tissues, employing no specific directional mechanisms. The distribution pattern in and around HVC could best be described by a random displacement model, where cells originating from the overlying lateral ventricle can move independently in any direction. Other plastic song control areas, such as the medial magnocellular nucleus of anterior nidopallium and the robust nucleus of arcopallium, were specifically avoided by migrating neurons, while migration toward the olfactory bulb showed high specificity, similar to the mammalian rostral migratory stream. Thus, different mechanisms appear to organize area-specific neuron recruitment in different recipients of the adult songbird brain, unrelated to global plasticity of brain regions.

  6. IFN gamma regulates proliferation and neuronal differentiation by STAT1 in adult SVZ niche.

    PubMed

    Pereira, Leticia; Medina, Rebeca; Baena, Miguel; Planas, Anna M; Pozas, Esther

    2015-01-01

    The adult subventricular zone (SVZ) is the main neurogenic niche in normal adult brains of mice and rats. Interferon gamma (IFNγ) has somewhat controversially been associated with SVZ progenitor proliferation and neurogenesis. The in vivo involvement of IFNγ in the physiology of the adult SVZ niche is not fully understood and its intracellular mediators are unknown. Here we show that IFNγ, through activation of its canonical signal transducer and activator of transcription 1 (STAT1) pathway, acts specifically on Nestin+ progenitors by decreasing both progenitor proliferation and the number of cycling cells. In addition, IFNγ increases the number of neuroblasts generated without shifting glial fate determination. The final result is deficient recruitment of newborn neurons to the olfactory bulb (OB), indicating that IFNγ-induced stimulation of neuronal differentiation does not compensate for its antiproliferative effect. We conclude that IFNγ signaling via STAT1 in the SVZ acts dually as an antiproliferative and proneurogenic factor, and thereby regulates neurogenesis in normal adult brains.

  7. Desvenlafaxine may accelerate neuronal maturation in the dentate gyri of adult male rats.

    PubMed

    Asokan, Aditya; Ball, Alan R; Laird, Christina D; Hermer, Linda; Ormerod, Brandi K

    2014-01-01

    Adult hippocampal neurogenesis has been linked to the effects of anti-depressant drugs on behavior in rodent models of depression. To explore this link further, we tested whether the serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine impacted adult hippocampal neurogenesis differently than its primary active SNRI metabolite desvenlafaxine. Adult male Long Evans rats (n = 5-6 per group) were fed vehicle, venlafaxine (0.5 or 5 mg) or desvenlafaxine (0.5 or 5 mg) twice daily for 16 days. Beginning the third day of drug treatment, the rats were given a daily bromodeoxyuridine (BrdU; 50 mg/kg) injection for 5 days to label dividing cells and then perfused 2 weeks after the first BrdU injection to confirm total new hippocampal cell numbers and their phenotypes. The high desvenlafaxine dose increased total new BrdU+ cell number and appeared to accelerate neuronal maturation because fewer BrdU+ cells expressed maturing neuronal phenotypes and more expressed mature neuronal phenotypes in the dentate gyri of these versus vehicle-treated rats. While net neurogenesis was not increased in the dentate gyri of rats treated with the high desvenlafaxine dose, significantly more mature neurons were detected. Our data expand the body of literature showing that antidepressants impact adult neurogenesis by stimulating NPC proliferation and perhaps the survival of neuronal progeny and by showing that a high dose of the SNRI antidepressant desvenlafaxine, but neither a high nor low venlafaxine dose, may also accelerate neuronal maturation in the adult rat hippocampus. These data support the hypothesis that hippocampal neurogenesis may indeed serve as a biomarker of depression and the effects of antidepressant treatment, and may be informative for developing novel fast-acting antidepressant strategies.

  8. 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

  9. 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

  10. 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.

  11. Dissecting the role of Engrailed in adult dopaminergic neurons--Insights into Parkinson disease pathogenesis.

    PubMed

    Rekaik, Hocine; Blaudin de Thé, François-Xavier; Prochiantz, Alain; Fuchs, Julia; Joshi, Rajiv L

    2015-12-21

    The homeoprotein Engrailed (Engrailed-1/Engrailed-2, collectively En1/2) is not only a survival factor for mesencephalic dopaminergic (mDA) neurons during development, but continues to exert neuroprotective and physiological functions in adult mDA neurons. Loss of one En1 allele in the mouse leads to progressive demise of mDA neurons in the ventral midbrain starting from 6 weeks of age. These mice also develop Parkinson disease-like motor and non-motor symptoms. The characterization of En1 heterozygous mice have revealed striking parallels to central mechanisms of Parkinson disease pathogenesis, mainly related to mitochondrial dysfunction and retrograde degeneration. Thanks to the ability of homeoproteins to transduce cells, En1/2 proteins have also been used to protect mDA neurons in various experimental models of Parkinson disease. This neuroprotection is partly linked to the ability of En1/2 to regulate the translation of certain nuclear-encoded mitochondrial mRNAs for complex I subunits. Other transcription factors that govern mDA neuron development (e.g. Foxa1/2, Lmx1a/b, Nurr1, Otx2, Pitx3) also continue to function for the survival and maintenance of mDA neurons in the adult and act through partially overlapping but also diverse mechanisms.

  12. Dissecting the role of Engrailed in adult dopaminergic neurons: Insights into Parkinson disease pathogenesis

    PubMed Central

    Rekaik, Hocine; Blaudin de Thé, François-Xavier; Prochiantz, Alain; Fuchs, Julia; Joshi, Rajiv L.

    2016-01-01

    The homeoprotein Engrailed (Engrailed-1/Engrailed-2, collectively En1/2) is not only a survival factor for mesencephalic dopaminergic (mDA) neurons during development, but continues to exert neuroprotective and physiological functions in adult mDA neurons. Loss of one En1 allele in the mouse leads to progressive demise of mDA neurons in the ventral midbrain starting from 6 weeks of age. These mice also develop Parkinson disease-like motor and non-motor symptoms. The characterization of En1 heterozygous mice have revealed striking parallels to central mechanisms of Parkinson disease pathogenesis, mainly related to mitochondrial dysfunction and retrograde degeneration. Thanks to the ability of homeoproteins to transduce cells, En1/2 proteins have also been used to protect mDA neurons in various experimental models of Parkinson disease. This neuroprotection is partly linked to the ability of En1/2 to regulate the translation of certain nuclear-encoded mitochondrial mRNAs for complex I subunits. Other transcription factors that govern mDA neuron development (e.g. Foxa1/2, Lmx1a/b, Nurr1, Otx2, Pitx3) also continue to function for the survival and maintenance of mDA neurons in the adult and act through partially overlapping but also diverse mechanisms. PMID:26459030

  13. Environment matters: synaptic properties of neurons born in the epileptic adult brain develop to reduce excitability.

    PubMed

    Jakubs, Katherine; Nanobashvili, Avtandil; Bonde, Sara; Ekdahl, Christine T; Kokaia, Zaal; Kokaia, Merab; Lindvall, Olle

    2006-12-21

    Neural progenitors in the adult dentate gyrus continuously produce new functional granule cells. Here we used whole-cell patch-clamp recordings to explore whether a pathological environment influences synaptic properties of new granule cells labeled with a GFP-retroviral vector. Rats were exposed to a physiological stimulus, i.e., running, or a brain insult, i.e., status epilepticus, which gave rise to neuronal death, inflammation, and chronic seizures. Granule cells formed after these stimuli exhibited similar intrinsic membrane properties. However, the new neurons born into the pathological environment differed with respect to synaptic drive and short-term plasticity of both excitatory and inhibitory afferents. The new granule cells formed in the epileptic brain exhibited functional connectivity consistent with reduced excitability. We demonstrate a high degree of plasticity in synaptic inputs to adult-born new neurons, which could act to mitigate pathological brain function.

  14. Hypoxia-ischemia induces DNA synthesis without cell proliferation in dying neurons in adult rodent brain.

    PubMed

    Kuan, Chia-Yi; Schloemer, Aryn J; Lu, Aigang; Burns, Kevin A; Weng, Wei-Lan; Williams, Michael T; Strauss, Kenneth I; Vorhees, Charles V; Flavell, Richard A; Davis, Roger J; Sharp, Frank R; Rakic, Pasko

    2004-11-24

    Recent studies suggest that postmitotic neurons can reenter the cell cycle as a prelude to apoptosis after brain injury. However, most dying neurons do not pass the G1/S-phase checkpoint to resume DNA synthesis. The specific factors that trigger abortive DNA synthesis are not characterized. Here we show that the combination of hypoxia and ischemia induces adult rodent neurons to resume DNA synthesis as indicated by incorporation of bromodeoxyuridine (BrdU) and expression of G1/S-phase cell cycle transition markers. After hypoxia-ischemia, the majority of BrdU- and neuronal nuclei (NeuN)-immunoreactive cells are also terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL)-stained, suggesting that they undergo apoptosis. BrdU+ neurons, labeled shortly after hypoxia-ischemia, persist for >5 d but eventually disappear by 28 d. Before disappearing, these BrdU+/NeuN+/TUNEL+ neurons express the proliferating cell marker Ki67, lose the G1-phase cyclin-dependent kinase (CDK) inhibitors p16INK4 and p27Kip1 and show induction of the late G1/S-phase CDK2 activity and phosphorylation of the retinoblastoma protein. This contrasts to kainic acid excitotoxicity and traumatic brain injury, which produce TUNEL-positive neurons without evidence of DNA synthesis or G1/S-phase cell cycle transition. These findings suggest that hypoxia-ischemia triggers neurons to reenter the cell cycle and resume apoptosis-associated DNA synthesis in brain. Our data also suggest that the demonstration of neurogenesis after brain injury requires not only BrdU uptake and mature neuronal markers but also evidence showing absence of apoptotic markers. Manipulating the aberrant apoptosis-associated DNA synthesis that occurs with hypoxia-ischemia and perhaps neurodegenerative diseases could promote neuronal survival and neurogenesis.

  15. Functional Integration of Adult-Born Hippocampal Neurons after Traumatic Brain Injury

    PubMed Central

    Villasana, Laura E.; Kim, Kristine N.

    2015-01-01

    Abstract Traumatic brain injury (TBI) increases hippocampal neurogenesis, which may contribute to cognitive recovery after injury. However, it is unknown whether TBI-induced adult-born neurons mature normally and functionally integrate into the hippocampal network. We assessed the generation, morphology, and synaptic integration of new hippocampal neurons after a controlled cortical impact (CCI) injury model of TBI. To label TBI-induced newborn neurons, we used 2-month-old POMC-EGFP mice, which transiently and specifically express EGFP in immature hippocampal neurons, and doublecortin-CreERT2 transgenic mice crossed with Rosa26-CAG-tdTomato reporter mice, to permanently pulse-label a cohort of adult-born hippocampal neurons. TBI increased the generation, outward migration, and dendritic complexity of neurons born during post-traumatic neurogenesis. Cells born after TBI had profound alterations in their dendritic structure, with increased dendritic branching proximal to the soma and widely splayed dendritic branches. These changes were apparent during early dendritic outgrowth and persisted as these cells matured. Whole-cell recordings from neurons generated during post-traumatic neurogenesis demonstrate that they are excitable and functionally integrate into the hippocampal circuit. However, despite their dramatic morphologic abnormalities, we found no differences in the rate of their electrophysiological maturation, or their overall degree of synaptic integration when compared to age-matched adult-born cells from sham mice. Our results suggest that cells born after TBI participate in information processing, and receive an apparently normal balance of excitatory and inhibitory inputs. However, TBI-induced changes in their anatomic localization and dendritic projection patterns could result in maladaptive network properties. PMID:26478908

  16. In Vivo Profiling Reveals a Competent Heat Shock Response in Adult Neurons: Implications for Neurodegenerative Disorders

    PubMed Central

    Carnemolla, Alisia; Lazell, Hayley; Moussaoui, Saliha; Bates, Gillian P.

    2015-01-01

    The heat shock response (HSR) is the main pathway used by cells to counteract proteotoxicity. The inability of differentiated neurons to induce an HSR has been documented in primary neuronal cultures and has been proposed to play a critical role in ageing and neurodegeneration. However, this accepted dogma has not been demonstrated in vivo. We used BAC transgenic mice generated by the Gene Expression Nervous System Atlas project to investigate the capacity of striatal medium sized spiny neurons to induce an HSR as compared to that of astrocytes and oligodendrocytes. We found that all cell populations were competent to induce an HSR upon HSP90 inhibition. We also show the presence and relative abundance of heat shock-related genes and proteins in these striatal cell populations. The identification of a competent HSR in adult neurons supports the development of therapeutics that target the HSR pathway as treatments for neurodegenerative disorders. PMID:26134141

  17. In Vivo Profiling Reveals a Competent Heat Shock Response in Adult Neurons: Implications for Neurodegenerative Disorders.

    PubMed

    Carnemolla, Alisia; Lazell, Hayley; Moussaoui, Saliha; Bates, Gillian P

    2015-01-01

    The heat shock response (HSR) is the main pathway used by cells to counteract proteotoxicity. The inability of differentiated neurons to induce an HSR has been documented in primary neuronal cultures and has been proposed to play a critical role in ageing and neurodegeneration. However, this accepted dogma has not been demonstrated in vivo. We used BAC transgenic mice generated by the Gene Expression Nervous System Atlas project to investigate the capacity of striatal medium sized spiny neurons to induce an HSR as compared to that of astrocytes and oligodendrocytes. We found that all cell populations were competent to induce an HSR upon HSP90 inhibition. We also show the presence and relative abundance of heat shock-related genes and proteins in these striatal cell populations. The identification of a competent HSR in adult neurons supports the development of therapeutics that target the HSR pathway as treatments for neurodegenerative disorders. PMID:26134141

  18. S100 protein-like immunoreactivity in the crypt olfactory neurons of the adult zebrafish.

    PubMed

    Germanà, A; Montalbano, G; Laurà, R; Ciriaco, E; del Valle, M E; Vega, José A

    2004-11-23

    The olfactory epithelium of some teleosts, including zebrafish, contains three types of olfactory sensory neurons. Because zebrafish has become an ideal model for the study of neurogenesis in the olfactory system, it is of capital importance the identification of specific markers for different neuronal populations. In this study we used immunohistochemistry to analyze the distribution of S100 protein-like in the adult zebrafish olfactory epithelium. Surprisingly, specific S100 protein-like immunostaining was detected exclusively in crypt neurons, whereas ciliated and microvillous neurons were not reactive, and the supporting glial cells as well. The pattern of immunostaining was exclusively cytoplasmic without apparent polarity within the soma, and the intensity of immunostaining was not related with the maturative stage of the neurons. The role of S100 protein in crypt olfactory neurons is unknown, although it is probably associated with the capacity of these cells to respond to chemical stimuli. In any case, it represents an excellent marker to identify crypt olfactory neurons in zebrafish.

  19. Environmental modulations of the number of midbrain dopamine neurons in adult mice.

    PubMed

    Tomas, Doris; Prijanto, Augustinus H; Burrows, Emma L; Hannan, Anthony J; Horne, Malcolm K; Aumann, Tim D

    2015-01-01

    Long-lasting changes in the brain or 'brain plasticity' underlie adaptive behavior and brain repair following disease or injury. Furthermore, interactions with our environment can induce brain plasticity. Increasingly, research is trying to identify which environments stimulate brain plasticity beneficial for treating brain and behavioral disorders. Two environmental manipulations are described which increase or decrease the number of tyrosine hydroxylase immunopositive (TH+, the rate-limiting enzyme in dopamine (DA) synthesis) neurons in the adult mouse midbrain. The first comprises pairing male and female mice together continuously for 1 week, which increases midbrain TH+ neurons by approximately 12% in males, but decreases midbrain TH+ neurons by approximately 12% in females. The second comprises housing mice continuously for 2 weeks in 'enriched environments' (EE) containing running wheels, toys, ropes, nesting material, etc., which increases midbrain TH+ neurons by approximately 14% in males. Additionally, a protocol is described for concurrently infusing drugs directly into the midbrain during these environmental manipulations to help identify mechanisms underlying environmentally-induced brain plasticity. For example, EE-induction of more midbrain TH+ neurons is abolished by concurrent blockade of synaptic input onto midbrain neurons. Together, these data indicate that information about the environment is relayed via synaptic input to midbrain neurons to switch on or off expression of 'DA' genes. Thus, appropriate environmental stimulation, or drug targeting of the underlying mechanisms, might be helpful for treating brain and behavioral disorders associated with imbalances in midbrain DA (e.g. Parkinson's disease, attention deficit and hyperactivity disorder, schizophrenia, and drug addiction).

  20. Regeneration and characterization of adult mouse hippocampal neurons in a defined in vitro system.

    PubMed

    Varghese, Kucku; Das, Mainak; Bhargava, Neelima; Stancescu, Maria; Molnar, Peter; Kindy, Mark S; Hickman, James J

    2009-02-15

    Although the majority of human illnesses occur during adulthood, most of the available in vitro disease models are based upon cells obtained from embryonic/fetal tissues because of the difficulties involved with culturing adult cells. Development of adult mouse neuronal cultures has a special significance because of the abundance of transgenic disease models that use this species. In this study a novel cell culture method has been developed that supports the long-term survival and physiological regeneration of adult mouse hippocampal cells in a serum-free defined environment. In this well-defined, controlled system, adult mouse hippocampal cells survived for up to 21 days in culture. The cultured cells exhibited typical hippocampal neuronal morphology and electrophysiological properties after recovery from the trauma of dissociation, and stained positive for the expected neuronal markers. This system has great potential as an investigative tool for in vitro studies of adult diseases, the aging brain or transgenic models of age-associated disorders. PMID:18955083

  1. 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.

  2. [Organized pain management in the DRG reimbursement system].

    PubMed

    Lindena, G; Gerbershagen, H U; Zenz, M; Laubenthal, H; Schleppers, A

    2005-02-01

    Multidisciplinary pain management in pain centers can only be guaranteed if the DRG reimbursement system takes into account the multiple risk factors. The German pain associations prospectively analyzed clinical and administrative (DRG-related) data sets (n=3943) of inpatient and day care pain treatment facilities. The index diagnoses of 84% of the patient sample were grouped into nine basic DRGs. The most frequent pain procedure code was 8-918 ("multimodal pain management"). The minimal length of stay for this code set to 7 days was 17.2 days for the study sample. The DRG grouper software 2003 categorized 68.6% of the patients into PCCL 0 despite the proven complexity of risks and secondary diseases. The mean case weight in the sample was set at about 1. The pain-related data set analyzing pain severity, chronicity, and its influence on various functions emphasizes the total severity and burden of disease and thus the necessity for multimodal pain management. The German pain societies carried the motion that a new complex ICD code for chronic pain (with biopsychosocial consequences) should be established in the German Modification of the ICD. The new ICD code F62.80 and the procedure code 8-918 had not yet been implemented into the German DRG algorithm. Due to modifications in DRG systematics and the DRG algorithm, to be activated in 2005, the procedure code 8-918 will now automatically trigger into four special basic pain DRGs corresponding to the index pain diagnosis.

  3. Aberrant Synaptic Integration in Adult Lamina I Projection Neurons Following Neonatal Tissue Damage

    PubMed Central

    Li, Jie; Kritzer, Elizabeth; Craig, Paige E.

    2015-01-01

    Mounting evidence suggests that neonatal tissue damage evokes alterations in spinal pain reflexes which persist into adulthood. However, less is known about potential concomitant effects on the transmission of nociceptive information to the brain, as the degree to which early injury modulates synaptic integration and membrane excitability in mature spinal projection neurons remains unclear. Here we demonstrate that neonatal surgical injury leads to a significant shift in the balance between synaptic excitation and inhibition onto identified lamina I projection neurons of the adult mouse spinal cord. The strength of direct primary afferent input to mature spino-parabrachial neurons was enhanced following neonatal tissue damage, whereas the efficacy of both GABAergic and glycinergic inhibition onto the same population was compromised. This was accompanied by reorganization in the pattern of sensory input to adult projection neurons, which included a greater prevalence of monosynaptic input from low-threshold A-fibers when preceded by early tissue damage. In addition, neonatal incision resulted in greater primary afferent-evoked action potential discharge in mature projection neurons. Overall, these results demonstrate that tissue damage during early life causes a long-term increase in the gain of spinal nociceptive circuits, and suggest that the prolonged consequences of neonatal trauma may not be restricted to the spinal cord but rather include excessive ascending signaling to supraspinal pain centers. PMID:25673839

  4. Adult Human Nasal Mesenchymal-Like Stem Cells Restore Cochlear Spiral Ganglion Neurons After Experimental Lesion

    PubMed Central

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

    2014-01-01

    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

  5. 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

  6. 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.

  7. Neonatal tissue injury reduces the intrinsic excitability of adult mouse superficial dorsal horn neurons.

    PubMed

    Li, J; Baccei, M L

    2014-01-01

    Tissue damage during the neonatal period evokes long-lasting changes in nociceptive processing within the adult spinal cord which contribute to persistent alterations in pain sensitivity. However, it remains unclear if the observed modifications in neuronal activity within the mature superficial dorsal horn (SDH) following early injury reflect shifts in the intrinsic membrane properties of these cells. Therefore, the present study was undertaken to identify the effects of neonatal surgical injury on the intrinsic excitability of both GABAergic and presumed glutamatergic neurons within lamina II of the adult SDH using in vitro patch clamp recordings from spinal cord slices prepared from glutamic acid decarboxylase-green fluorescent protein (Gad-GFP) mice. The results demonstrate that hindpaw surgical incision at postnatal day (P) 3 altered the passive membrane properties of both Gad-GFP and adjacent, non-GFP neurons in the mature SDH, as evidenced by decreased membrane resistance and more negative resting potentials in comparison to naïve littermate controls. This was accompanied by a reduction in the prevalence of spontaneous activity within the GABAergic population. Both Gad-GFP and non-GFP neurons displayed a significant elevation in rheobase and decreased instantaneous firing frequency after incision, suggesting that early tissue damage lowers the intrinsic membrane excitability of adult SDH neurons. Isolation of inward-rectifying K(+) (K(ir)) currents revealed that neonatal incision significantly increased K(ir) conductance near physiological membrane potentials in GABAergic, but not glutamatergic, lamina II neurons. Overall, these findings suggest that neonatal tissue injury causes a long-term dampening of intrinsic firing across the general population of lamina II interneurons, but the underlying ionic mechanisms may be cell-type specific.

  8. Adult retinal pigment epithelium cells express neural progenitor properties and the neuronal precursor protein doublecortin.

    PubMed

    Engelhardt, Maren; Bogdahn, Ulrich; Aigner, Ludwig

    2005-04-01

    The adult mammalian retina is devoid of any detectable neurogenesis. However, different cell types have been suggested to potentially act as neural progenitors in the adult mammalian retina in vitro, such as ciliary body (CB), Muller glia, and retinal pigment epithelium (RPE) cells. In rodents and humans, strong evidence for neural stem or progenitor properties exists only for CB-derived cells, but not for other retinal cell types. Here, we provide a comparative analysis of adult rat CB- and RPE-derived cells suggesting that the two cell types share certain neural progenitor properties in vitro. CB and RPE cells expressed neural progenitor markers such as Nestin, Flk-1, Hes1, and Musashi. They proliferated under adherent and neurosphere conditions and showed limited self-renewal. Moreover, they differentiated into neuronal and glial cells based on the expression of differentiation markers such as the young neuronal marker beta-III tubulin and the glial and progenitor markers GFAP and NG2. Expression of beta-III tubulin was found in cells with neuronal and non-neuronal morphology. A subpopulation of RPE- and CB-derived progenitor cells expressed the neurogenesis-specific protein doublecortin (DCX). Interestingly, DCX expression defined a beta-III tubulin-positive CB and RPE fraction with a distinct neuronal morphology. In summary, the data suggest that RPE cells share with CB cells the potential to de-differentiate into a cell type with neural progenitor-like identity. In addition, DCX expression might define the neuronal-differentiating RPE- and CB-derived progenitor population. PMID:15804431

  9. 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.

  10. Generation of cloned mice from adult neurons by direct nuclear transfer.

    PubMed

    Mizutani, Eiji; Oikawa, Mami; Kassai, Hidetoshi; Inoue, Kimiko; Shiura, Hirosuke; Hirasawa, Ryutaro; Kamimura, Satoshi; Matoba, Shogo; Ogonuki, Narumi; Nagatomo, Hiroaki; Abe, Kuniya; Wakayama, Teruhiko; Aiba, Atsu; Ogura, Atsuo

    2015-03-01

    Whereas cloning mammals by direct somatic cell nuclear transfer has been successful using a wide range of donor cell types, neurons from adult brain remain "unclonable" for unknown reasons. Here, using a combination of two epigenetic approaches, we examined whether neurons from adult mice could be cloned. First, we used a specific antibody to discover cell types with reduced amounts of a repressive histone mark-dimethylated histone H3 lysine 9 (H3K9me2)-and identified CA1 pyramidal cells in the hippocampus and Purkinje cells in the cerebellum as candidates. Second, reconstructed embryos were treated with trichostatin A (TSA), a potent histone deacetylase inhibitor. Using CA1 cells, cloned offspring were obtained at high rates, reaching 10.2% and 4.6% (of embryos transferred) for male and female donors, respectively. Cerebellar Purkinje cell nuclei were too large to maintain their genetic integrity during nuclear transfer, leading to developmental arrest of embryos. However, gene expression analysis using cloned blastocysts corroborated a high rate of genomic reprogrammability of CA1 pyramidal and Purkinje cells. Neurons from the hippocampal dentate gyrus and cerebral cortex, which had higher amounts of H3K9me2, could also be used for producing cloned offspring, but the efficiencies were low. A more thorough analysis revealed that TSA treatment was essential for cloning adult neuronal cells. This study demonstrates, to our knowledge for the first time, that adult neurons can be cloned by nuclear transfer. Furthermore, our data imply that reduced amounts of H3K9me2 and increased histone acetylation appear to act synergistically to improve the development of cloned embryos.

  11. 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

  12. CYTOPLASMIC INCLUSIONS RESEMBLING NUCLEOLI IN SYMPATHETIC NEURONS OF ADULT RATS

    PubMed Central

    Grillo, Mary A.

    1970-01-01

    A distinctive cytoplasmic inclusion consisting of a convoluted network of electron-opaque strands embedded in a less dense matrix was identified in the neurons, but not in the supporting cells, of rat sympathetic ganglia. This ball-like structure, designated "nematosome," measures ∼ 0.9 µ and lacks a limiting membrane. Its strands (diameter = 400–600 A) appear to be made of an entanglement of tightly packed filaments and particles ∼ 25–50 A thick. Cytochemical studies carried out with the light microscope suggest the presence of nonhistone proteins and some RNA. Usually only one such structure is present in a cell, and it appears to occur in most ganglion cells. Although they can be seen anywhere in the cell body, nematosomes are typically located in the perinuclear cytoplasm, where they are often associated with smooth-surfaced and coated vesicles. In fine structure and stainability, they bear a resemblance to the fibrous component of the nucleolus. Subsynaptic formations, which are a special feature of some of the synapses in sympathetic ganglia, appear similar to the threadlike elements in the nematosomes. The possibility that these three structures—nucleolus, nematosome, and subsynaptic formation—may be interrelated in origin and function is discussed. PMID:5458990

  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. Generation of glutamatergic neurons from postnatal and adult subventricular zone with pyramidal-like morphology.

    PubMed

    Sequerra, Eduardo B; Miyakoshi, Leo M; Fróes, Maira M; Menezes, João R L; Hedin-Pereira, Cecilia

    2010-11-01

    The mammalian subventricular zone (SVZ) contains progenitors derived from cerebral cortex radial glia cells, which give rise to glutamatergic pyramidal neurons during embryogenesis. However, during postnatal life, SVZ generates neurons that migrate and differentiate into olfactory bulb γ-aminobutyric acid (GABA)ergic interneurons. In this work, we tested if SVZ cells are able to produce glutamatergic neurons if confronted with the embryonic cortical ventricular zone environment. Different from typical SVZ chain migration, cells from P9-P11 SVZ explants migrate into embryonic cortical slices individually, many of which radially oriented. An average of 82.5% of green fluorescent protein-positive cells were immunolabeled for neuronal marker class III β-tubulin. Invading cells differentiate into multiple morphologies, including a pyramidal-like morphotype. A subset of these cells are GABAergic; however, about 28% of SVZ-derived cells are immunoreactive for glutamate. Adult SVZ explants also give rise to glutamatergic neurons in these conditions. Taken together, our results indicate that SVZ can be a source of glutamatergic cortical neurons when submitted to proper environmental cues.

  16. 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

  17. 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

  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. Civilian Health and Medical Program of the Uniformed Services (CHAMPUS); FY97 DRG updates--DoD. Notice of DRG revised rates.

    PubMed

    1996-10-17

    This notice provides the updated adjusted standardized amounts, DRG relative weights, outlier thresholds, and beneficiary cost-share per diem rates to be used for FY 1997 under the CHAMPUS DRG-based payment system. It also describes the changes made to the CHAMPUS DRG-based payment system in order to conform to changes made to the Medicare Prospective Payment System (PPS).

  20. Effects of urethane on the response properties of visual cortical neurons in young adult and old cats.

    PubMed

    Peng, Qing-Song; Zhou, Jun; Shi, Xia-Ming; Hua, Guo-Peng; Hua, Tian-Miao

    2011-06-01

    Previous studies have shown that visual cortical neurons in old mammals exhibit higher spontaneous activity, higher responsiveness to visual stimuli, and lower selectivity for stimulus orientations and motion directions than did neurons in young adult counterparts. However, whether the responsive difference in cortical neurons between young and old animals resulted from different effects induced by anesthetics has remained unclear. To clarify this issue, we recorded the response properties of individual neurons in the primary visual cortex of old and young adult cats while systematically varying the anesthesia level of urethane, a widely used anesthetic in physiology experiments. Our results showed that cumulatively administrating 50 mg and 100 mg of urethane upon the minimal level of urethane required to anesthetize an old or young adult cat did not significantly alter the degree of neuronal response selectivity for stimulus orientations and motion directions nor significantly change the visually-driven response and spontaneous activity of neurons in old and young adult cats. Cumulatively administrating 150 mg of urethane decreased neuronal responsiveness similarly in both age groups. Therefore, urethane appears to exert similar effects on neuronal response properties of old and young adult animals. PMID:21698802

  1. Trim9 Deletion Alters the Morphogenesis of Developing and Adult-Born Hippocampal Neurons and Impairs Spatial Learning and Memory

    PubMed Central

    Winkle, Cortney C.; Olsen, Reid H. J.; Kim, Hyojin; Moy, Sheryl S.

    2016-01-01

    During hippocampal development, newly born neurons migrate to appropriate destinations, extend axons, and ramify dendritic arbors to establish functional circuitry. These developmental stages are recapitulated in the dentate gyrus of the adult hippocampus, where neurons are continuously generated and subsequently incorporate into existing, local circuitry. Here we demonstrate that the E3 ubiquitin ligase TRIM9 regulates these developmental stages in embryonic and adult-born mouse hippocampal neurons in vitro and in vivo. Embryonic hippocampal and adult-born dentate granule neurons lacking Trim9 exhibit several morphological defects, including excessive dendritic arborization. Although gross anatomy of the hippocampus was not detectably altered by Trim9 deletion, a significant number of Trim9−/− adult-born dentate neurons localized inappropriately. These morphological and localization defects of hippocampal neurons in Trim9−/− mice were associated with extreme deficits in spatial learning and memory, suggesting that TRIM9-directed neuronal morphogenesis may be involved in hippocampal-dependent behaviors. SIGNIFICANCE STATEMENT Appropriate generation and incorporation of adult-born neurons in the dentate gyrus are critical for spatial learning and memory and other hippocampal functions. Here we identify the brain-enriched E3 ubiquitin ligase TRIM9 as a novel regulator of embryonic and adult hippocampal neuron shape acquisition and hippocampal-dependent behaviors. Genetic deletion of Trim9 elevated dendritic arborization of hippocampal neurons in vitro and in vivo. Adult-born dentate granule cells lacking Trim9 similarly exhibited excessive dendritic arborization and mislocalization of cell bodies in vivo. These cellular defects were associated with severe deficits in spatial learning and memory. PMID:27147649

  2. Viral vector mediated continuous expression of interleukin-10 in DRG alleviates pain in type 1 diabetic animals.

    PubMed

    Thakur, Vikram; Gonzalez, Mayra; Pennington, Kristen; Chattopadhyay, Munmun

    2016-04-01

    Painful diabetic neuropathy is a common and difficult to treat complication of diabetes. A growing body of evidence implicates the role of inflammatory mediators in the damage to the peripheral axons and in the pathogenesis of neuropathic pain. Increased expression of pro-inflammatory cytokines such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α in the peripheral nervous system suggests the possibility of change in pain perception in diabetes. In this study we investigated that continuous delivery of IL10 in the nerve fibers achieved by HSV vector mediated transduction of dorsal root ganglion (DRG) in animals with Type 1 diabetes, blocks the nociceptive and stress responses in the DRG neurons by reducing IL1β expression along with inhibition of phosphorylation of p38 MAPK (mitogen-activated protein kinase) and protein kinase C (PKC). The continuous expression of IL10 also alters Toll like receptor (TLR)-4 expression in the DRG with increased expression of heat shock protein (HSP)-70 in conjunction with the reduction of pain. Taken together, this study suggests that macrophage activation in the peripheral nervous system may be involved in the pathogenesis of pain in Type 1 diabetes and therapeutic benefits of HSV mediated local expression of IL10 in the DRG with the reduction of a number of proinflammatory cytokines, subsequently inhibits the development of painful neuropathy along with a decrease in stress associated markers in the DRG. This basic and preclinical study provides an important evidence for a novel treatment strategy that could lead to a clinical trial for what is currently a treatment resistant complication of diabetes. PMID:26802537

  3. 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

  4. Aquaporin-1 water permeability as a novel determinant of axonal regeneration in dorsal root ganglion neurons.

    PubMed

    Zhang, Hua; Verkman, A S

    2015-03-01

    Dorsal root ganglion (DRG) neurons transduce peripheral pain signals through small-diameter, non-myelinated C-fibers, which, when injured, can regenerate to restore pain sensation. Water channel aquaporin-1 (AQP1) is expressed at the plasma membrane of cell bodies and axons of DRG neurons, where it modulates the sensing of certain types of pain. Here, we found that AQP1 is also involved in DRG axonal growth and regeneration by a mechanism that may involve water transport-facilitated extension of axonal outgrowths. Spontaneous and nerve growth factor-stimulated axonal extension was reduced in cultures of AQP1-deficient DRG neurons and DRG explants compared to the wildtype. Axonal growth in AQP1-deficient DRG cultures was rescued by transfection with AQP1 or a different water-transporting AQP (AQP4), but not by a non-water-transporting AQP1 mutant. Following sciatic nerve compression injury AQP1 expression was increased in DRG neurons in wildtype mice, and DRG axonal growth was impaired in AQP1-deficient mice. Our results indicate AQP1 as a novel determinant of DRG axonal regeneration and hence a potential therapeutic target to accelerate neuronal regeneration.

  5. AQUAPORIN-1 WATER PERMEABILITY AS A NOVEL DETERMINANT OF AXONAL REGENERATION IN DORSAL ROOT GANGLION NEURONS

    PubMed Central

    Zhang, Hua; Verkman, A.S.

    2015-01-01

    Dorsal root ganglion (DRG) neurons transduce peripheral pain signals through small-diameter, non-myelinated C-fibers, which, when injured, can regenerate to restore pain sensation. Water channel aquaporin-1 (AQP1) is expressed at the plasma membrane of cell bodies and axons of DRG neurons, where it modulates the sensing of certain types of pain. Here, we found that AQP1 is also involved in DRG axonal growth and regeneration by a mechanism that may involve water transport-facilitated extension of axonal outgrowths. Spontaneous and nerve growth factor-stimulated axonal extension was reduced in cultures of AQP1-deficient DRG neurons and DRG explants compared to the wildtype. Axonal growth in AQP1-deficient DRG cultures was rescued by transfection with AQP1 or a different water-transporting AQP (AQP4), but not by a non-water-transporting AQP1 mutant. Following sciatic nerve compression injury AQP1 expression was increased in DRG neurons in wildtype mice, and DRG axonal growth was impaired in AQP1-deficient mice. Our results indicate AQP1 as a novel determinant of DRG axonal regeneration and hence a potential therapeutic target to accelerate neuronal regeneration. PMID:25585012

  6. 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.

  7. Unilateral eye enucleation in adult rats causes neuronal loss in the contralateral superior colliculus

    PubMed Central

    SMITH, S. A.; BEDI, K. S.

    1997-01-01

    Several studies have reported the morphological changes induced by unilateral enucleation during early neonatal life on the developing visual system. This study has examined cellular changes in the superior colliculi by removal of a single eye in adult rats. Anaesthetised male hooded rats aged 90 d had their right eyes removed. Groups of nonenucleated control and enucleated rats were killed when aged either 150 or 390 d. The brains were removed and both the right and left superior colliculi dissected out. The volume of the stratum griseum superficiale (SGS) within these colliculi was estimated stereologically by light microscopy, as well as the numerical density and total number of neurons within this cell layer. The volume of the cell layer was reduced by about 40% on the side contralateral to the enucleated eye but not on the ipsilateral side at both survival periods examined. The numerical density of neurons within the SGS was unaffected by the enucleation so that the colliculi contralateral to the enucleated eye showed a substantial loss of neurons within this cell layer. This study demonstrates the importance of the retinal ganglion cell input, even in adult animals, for maintaining the viability of neurons in the SGS layer of the superior colliculus. PMID:9183672

  8. Investigating DRG cost weights for hospitals in middle income countries.

    PubMed

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

    2009-01-01

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

  9. Pediatric patients, race, and DRG prospective hospital payment.

    PubMed

    Munoz, E; Barrios, E; Johnson, H; Goldstein, J; Mulloy, K; Chalfin, D; Wise, L

    1989-05-01

    The diagnosis related group (DRG) prospective hospital payment system contains inequities in hospital payment for certain groups of patients. Patients of lower socioeconomic status may be underreimbursed by DRGs. We analyzed pediatric patients and hospital resource consumption by race (white, Hispanic, and black) using a DRG prospective payment "all payer" system. All hospitalized pediatric admissions over a 3-year period (N = 14,489) were analyzed by race at a large academic medical center. Mean hospital length of stay and cost per patient (adjusted for DRG weight index) was significantly greater for black and Hispanic pediatric patients compared with whites. Financial risk as measured by outliers and losses under DRGs was greater for blacks and Hispanics compared with whites. Black and Hispanic patients had a higher proportion of emergency admission to the hospital compared with whites, a greater severity of illness (as measured by total International Classification of Diseases, ninth revision, Clinical Modification codes), and (on average) higher diagnostic costs for each episode of illness. Our data suggest that black and Hispanic pediatric patients have a greater hospital resource consumption (adjusted for DRG group case mix) compared with whites, at least at our large medical center in the Northeast. Hospitals that treat greater numbers of black and Hispanic pediatric patients may be at a substantial disadvantage under per-case DRG payment.

  10. Nerve growth factor in the urinary bladder of the adult regulates neuronal form and function.

    PubMed Central

    Steers, W D; Kolbeck, S; Creedon, D; Tuttle, J B

    1991-01-01

    Urethral obstruction produces increased voiding frequency (0.7 +/- 0.06 to 1.1 +/- 0.08 h-1) and hypertrophy of the urinary bladder (89 +/- 1.7 to 708 +/- 40 mg) with profound increments in the dimensions of afferent (4, 6) and efferent neurons (299 +/- 4.7 to 573 +/- 8.6 microns2) supplying this organ in the rat. We discovered that hypertrophied bladders of rat and human contain significantly more nerve growth factor (NGF) per milligram wet weight, protein, and DNA than normal bladders. The temporal correlation between NGF content, neuronal hypertrophy, and bladder weight was consistent with a role for this growth factor in the neurotrophic effects associated with obstruction. Autoimmunity to NGF abolished the hypertrophy of NGF-sensitive bladder neurons in the pelvic ganglion after obstruction. Relief of urethral obstruction reduced bladder size (349 +/- 78 mg), but neuronal hypertrophy (460.2 +/- 10.2 microns2) and elevated NGF levels were only partially reversed. Bladder hypertrophy (133 +/- 4.3 mg) induced by osmotic diuresis slightly increased ganglion cell area (365.2 +/- 6.1 microns2) and only doubled NGF content of the bladder. These findings provide important new evidence that parenchymal cells in the hypertrophied bladder can synthesize NGF and possibly other molecular messengers that act to alter the size and function of neurons in adult animals and man. Images PMID:1939656

  11. P53 regulates disruption of neuronal development in the adult hippocampus after irradiation

    PubMed Central

    Li, Y-Q; Cheng, ZW-C; Liu, SK-W; Aubert, I; Wong, C S

    2016-01-01

    Inhibition of hippocampal neurogenesis is implicated in neurocognitive dysfunction after cranial irradiation for brain tumors. How irradiation results in impaired neuronal development remains poorly understood. The Trp53 (p53) gene is known to regulate cellular DNA damage response after irradiation. Whether it has a role in disruption of late neuronal development remains unknown. Here we characterized the effects of p53 on neuronal development in adult mouse hippocampus after irradiation. Different bromodeoxyuridine incorporation paradigms and a transplantation study were used for cell fate mapping. Compared with wild-type mice, we observed profound inhibition of hippocampal neurogenesis after irradiation in mice deficient in p53 despite the absence of acute apoptosis of neuroblasts. The putative neural stem cells were apoptosis resistant after irradiation regardless of p53 genotype. Cell fate mapping using different bromodeoxyuridine incorporation paradigms revealed enhanced activation of neural stem cells and their consequential exhaustion in the absence of p53 after irradiation. Both p53-knockout and wild-type mice demonstrated similar extent of microglial activation in the hippocampus after irradiation. Impairment of neuronal differentiation of neural progenitors transplanted in irradiated hippocampus was not altered by p53 genotype of the recipient mice. We conclude that by inhibiting neural progenitor activation, p53 serves to mitigate disruption of neuronal development after irradiation independent of apoptosis and perturbation of the neural stem cell niche. These findings suggest for the first time that p53 may have a key role in late effects in brain after irradiation. PMID:27752364

  12. Toxic effects of bortezomib on primary sensory neurons and Schwann cells of adult mice.

    PubMed

    Alé, Albert; Bruna, Jordi; Herrando, Mireia; Navarro, Xavier; Udina, Esther

    2015-05-01

    The proteasome inhibitor bortezomib is nowadays first line treatment for multiple myeloma. One of the most significant adverse events is peripheral neuropathy, mainly involving sensory nerve fibers that can lead to withdrawal of treatment. Here we develop an in vitro model to compare the effects of bortezomib on primary sensory neurons and Schwann cells of adult mice. We observed that sensory neurons were more susceptible to bortezomib, and their viability was reduced at a concentration of 6 nM, that only affected Schwann cell proliferation but not survival. At concentration higher than 8 nM Schwann cell viability was also compromised. Already at low concentrations, surviving neurons presented alterations in neurite outgrowth. Neurites were shorter and had dystrophic appearance, with alterations in neurofilament staining. However, neurites were able to regrow after removing bortezomib from the medium, thus indicating reversibility of the neurotoxicity. We confirmed in vivo that bortezomib produced alterations in neurofilaments at early stages of the treatment. After an accumulated dose of 2 mg/kg bortezomib, dorsal root ganglia neurons of treated animals showed accumulation of neurofilament in the soma. To evaluate if this accumulation was related with alterations in axonal transport, we tested the ability of sensory neurons to retrogradely transport a retrotracer applied at the distal nerve. Treated animals showed a lower amount of retrotracer in the soma 24 h after its application to the tibial nerve, therefore suggesting that axonal transport was affected by bortezomib.

  13. 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.

  14. Altered neuronal architecture and plasticity in the visual cortex of adult MMP-3-deficient mice.

    PubMed

    Aerts, Jeroen; Nys, Julie; Moons, Lieve; Hu, Tjing-Tjing; Arckens, Lutgarde

    2015-09-01

    Matrix metalloproteinases (MMPs) are Zn(2+)-dependent endopeptidases considered to be essential for normal brain development and neuroplasticity by modulating extracellular matrix proteins, receptors, adhesion molecules, growth factors and cytoskeletal proteins. Specifically, MMP-3 has recently been implicated in synaptic plasticity, hippocampus-dependent learning and neuronal development and migration in the cerebellum. However, the function(s) of this enzyme in the neocortex is understudied. Therefore, we explored the phenotypical characteristics of the neuronal architecture and the capacity for experience-dependent cortical plasticity in the visual cortex of adult MMP-3-deficient (MMP-3(-/-)) mice. Golgi-Cox stainings revealed a significant reduction in apical dendritic length and an increased number of apical obliques for layer V pyramidal neurons in the visual cortex of adult MMP-3(-/-) mice compared to wild-type (WT) animals. In addition, a significant upregulation of both phosphorylated and non-phosphorylated neurofilament protein (NF)-high, phosphorylated NF-medium, NF-low and α-internexin was detected in the visual cortex of MMP-3(-/-) mice. To assess the effect of MMP-3 deficiency on cortical plasticity, we monocularly enucleated adult MMP-3(-/-) mice and analyzed the reactivation of the contralateral visual cortex 7 weeks post-enucleation. In contrast to previous results in C57Bl/6J adult mice, activity remained confined to the binocular zone and did not expand into the monocular regions indicative for an aberrant open-eye potentiation. Permanent hypoactivity in the monocular cortex lateral and medial to V1 also indicated a lack of cross-modal plasticity. These observations demonstrate that genetic inactivation of MMP-3 has profound effects on the structural integrity and plasticity response of the visual cortex of adult mice.

  15. Neonatal maternal deprivation sensitizes voltage-gated sodium channel currents in colon-specific dorsal root ganglion neurons in rats.

    PubMed

    Hu, Shufen; Xiao, Ying; Zhu, Liyan; Li, Lin; Hu, Chuang-Ying; Jiang, Xinghong; Xu, Guang-Yin

    2013-02-15

    Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by abdominal pain in association with altered bowel movements. The underlying mechanisms of visceral hypersensitivity remain elusive. This study was designed to examine the role for sodium channels in a rat model of chronic visceral hyperalgesia induced by neonatal maternal deprivation (NMD). Abdominal withdrawal reflex (AWR) scores were performed on adult male rats. Colon-specific dorsal root ganglion (DRG) neurons were labeled with DiI and acutely dissociated for measuring excitability and sodium channel current under whole-cell patch-clamp configurations. The expression of Na(V)1.8 was analyzed by Western blot and quantitative real-time PCR. NMD significantly increased AWR scores, which lasted for ~6 wk in an association with hyperexcitability of colon DRG neurons. TTX-resistant but not TTX-sensitive sodium current density was greatly enhanced in colon DRG neurons in NMD rats. Compared with controls, activation curves showed a leftward shift in NMD rats whereas inactivation curves did not differ significantly. NMD markedly accelerated the activation time of peak current amplitude without any changes in inactivation time. Furthermore, NMD remarkably enhanced expression of Na(V)1.8 at protein levels but not at mRNA levels in colon-related DRGs. The expression of Na(V)1.9 was not altered after NMD. These data suggest that NMD enhances TTX-resistant sodium activity of colon DRG neurons, which is most likely mediated by a leftward shift of activation curve and by enhanced expression of Na(V)1.8 at protein levels, thus identifying a specific molecular mechanism underlying chronic visceral pain and sensitization in patients with IBS. PMID:23139220

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

    PubMed Central

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

    2012-01-01

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

  17. 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

  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

    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

    2009-04-01

    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-knockout (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 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.

  19. 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

  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. IFN gamma regulates proliferation and neuronal differentiation by STAT1 in adult SVZ niche

    PubMed Central

    Pereira, Leticia; Medina, Rebeca; Baena, Miguel; Planas, Anna M.; Pozas, Esther

    2015-01-01

    The adult subventricular zone (SVZ) is the main neurogenic niche in normal adult brains of mice and rats. Interferon gamma (IFNγ) has somewhat controversially been associated with SVZ progenitor proliferation and neurogenesis. The in vivo involvement of IFNγ in the physiology of the adult SVZ niche is not fully understood and its intracellular mediators are unknown. Here we show that IFNγ, through activation of its canonical signal transducer and activator of transcription 1 (STAT1) pathway, acts specifically on Nestin+ progenitors by decreasing both progenitor proliferation and the number of cycling cells. In addition, IFNγ increases the number of neuroblasts generated without shifting glial fate determination. The final result is deficient recruitment of newborn neurons to the olfactory bulb (OB), indicating that IFNγ-induced stimulation of neuronal differentiation does not compensate for its antiproliferative effect. We conclude that IFNγ signaling via STAT1 in the SVZ acts dually as an antiproliferative and proneurogenic factor, and thereby regulates neurogenesis in normal adult brains. PMID:26217191

  2. Central artery stiffness, baroreflex sensitivity, and brain white matter neuronal fiber integrity in older adults.

    PubMed

    Tarumi, Takashi; de Jong, Daan L K; Zhu, David C; Tseng, Benjamin Y; Liu, Jie; Hill, Candace; Riley, Jonathan; Womack, Kyle B; Kerwin, Diana R; Lu, Hanzhang; Munro Cullum, C; Zhang, Rong

    2015-04-15

    Cerebral hypoperfusion elevates the risk of brain white matter (WM) lesions and cognitive impairment. Central artery stiffness impairs baroreflex, which controls systemic arterial perfusion, and may deteriorate neuronal fiber integrity of brain WM. The purpose of this study was to examine the associations among brain WM neuronal fiber integrity, baroreflex sensitivity (BRS), and central artery stiffness in older adults. Fifty-four adults (65 ± 6 years) with normal cognitive function or mild cognitive impairment (MCI) were tested. The neuronal fiber integrity of brain WM was assessed from diffusion metrics acquired by diffusion tensor imaging. BRS was measured in response to acute changes in blood pressure induced by bolus injections of vasoactive drugs. Central artery stiffness was measured by carotid-femoral pulse wave velocity (cfPWV). The WM diffusion metrics including fractional anisotropy (FA) and radial (RD) and axial (AD) diffusivities, BRS, and cfPWV were not different between the control and MCI groups. Thus, the data from both groups were combined for subsequent analyses. Across WM, fiber tracts with decreased FA and increased RD were associated with lower BRS and higher cfPWV, with many of the areas presenting spatial overlap. In particular, the BRS assessed during hypotension was strongly correlated with FA and RD when compared with hypertension. Executive function performance was associated with FA and RD in the areas that correlated with cfPWV and BRS. These findings suggest that baroreflex-mediated control of systemic arterial perfusion, especially during hypotension, may play a crucial role in maintaining neuronal fiber integrity of brain WM in older adults. PMID:25623500

  3. 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

  4. 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

  5. Neuropeptide Y stimulates neuronal precursor proliferation in the post-natal and adult dentate gyrus.

    PubMed

    Howell, Owain W; Doyle, Kharen; Goodman, Jeffrey H; Scharfman, Helen E; Herzog, Herbert; Pringle, Ashley; Beck-Sickinger, Annette G; Gray, William P

    2005-05-01

    Adult dentate neurogenesis is important for certain types of hippocampal-dependent learning and also appears to be important for the maintenance of normal mood and the behavioural effects of antidepressants. Neuropeptide Y (NPY), a peptide neurotransmitter released by interneurons in the dentate gyrus, has important effects on mood, anxiety-related behaviour and learning and memory. We report that adult NPY receptor knock-out mice have significantly reduced cell proliferation and significantly fewer immature doublecortin-positive neurons in the dentate gyrus. We also show that the neuroproliferative effect of NPY is dentate specific, is Y1-receptor mediated and involves extracellular signal-regulated kinase (ERK)1/2 activation. NPY did not exhibit any effect on cell survival in vitro but constitutive loss of the Y1 receptor in vivo resulted in greater survival of newly generated neurons and an unchanged total number of dentate granule cells. These results show that NPY stimulates neuronal precursor proliferation in the dentate gyrus and suggest that NPY-releasing interneurons may modulate dentate neurogenesis.

  6. Altered adult hippocampal neuronal maturation in a rat model of fetal alcohol syndrome.

    PubMed

    Gil-Mohapel, Joana; Boehme, Fanny; Patten, Anna; Cox, Adrian; Kainer, Leah; Giles, Erica; Brocardo, Patricia S; Christie, Brian R

    2011-04-12

    Exposure to ethanol during pregnancy can be devastating to the developing nervous system, leading to significant central nervous system dysfunction. The hippocampus, one of the two brain regions where neurogenesis persists into adulthood, is particularly sensitive to the teratogenic effects of ethanol. In the present study, we tested a rat model of fetal alcohol syndrome (FAS) with ethanol administered via gavage throughout all three trimester equivalents. Subsequently, we assessed cell proliferation, as well as neuronal survival, and differentiation in the dentate gyrus of the hippocampus of adolescent (35 days old), young adult (60 days old) and adult (90 days old) Sprague-Dawley rats. Using both extrinsic (bromodeoxyuridine) and intrinsic (Ki-67) markers, we observed no significant alterations in cell proliferation and survival in ethanol-exposed animals when compared with their pair-fed and ad libitum controls. However, we detected a significant increase in the number of new immature neurons in animals that were exposed to ethanol throughout all three trimester equivalents. This result might reflect a compensatory mechanism to counteract the deleterious effects of prenatal ethanol exposure or an ethanol-induced arrest of the neurogenic process at the early neuronal maturation stages. Taken together these results indicate that exposure to ethanol during the period of brain development causes a long-lasting dysregulation of the neurogenic process, a mechanism that might contribute, at least in part, to the hippocampal deficits that have been reported in rodent models of FAS.

  7. 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

  8. Pericytes control key neurovascular functions and neuronal phenotype in the adult brain and during brain aging

    PubMed Central

    Bell, Robert D.; Winkler, Ethan A.; Sagare, Abhay P.; Singh, Itender; LaRue, Barb; Deane, Rashid; Zlokovic, Berislav V.

    2010-01-01

    SUMMARY Pericytes play a key role in the development of cerebral microcirculation. The exact role of pericytes in the neurovascular unit in the adult brain and during brain aging remains, however, elusive. Using adult viable pericyte-deficient mice, we show that pericyte loss leads to brain vascular damage by two parallel pathways: (1) reduction in brain microcirculation causing diminished brain capillary perfusion, cerebral blood flow and cerebral blood flow responses to brain activation which ultimately mediates chronic perfusion stress and hypoxia, and (2) blood-brain barrier breakdown associated with brain accumulation of serum proteins and several vasculotoxic and/or neurotoxic macromolecules ultimately leading to secondary neuronal degenerative changes. We show that age-dependent vascular damage in pericyte-deficient mice precedes neuronal degenerative changes, learning and memory impairment and the neuroinflammatory response. Thus, pericytes control key neurovascular functions that are necessary for proper neuronal structure and function, and pericytes loss results in a progressive age-dependent vascular-mediated neurodegeneration. PMID:21040844

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

    PubMed Central

    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

    2015-01-01

    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

  10. 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

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

    PubMed

    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

  12. 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

  13. 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.

  14. Role of neuronal ras activity in adult hippocampal neurogenesis and cognition.

    PubMed

    Manns, Martina; Leske, Oliver; Gottfried, Sebastian; Bichler, Zoë; Lafenêtre, Pauline; Wahle, Petra; Heumann, Rolf

    2011-01-01

    Hippocampal neurogenesis in the adult mammalian brain is modulated by various signals like growth factors, hormones, neuropeptides, and neurotransmitters. All of these factors can (but not necessarily do) converge on the activation of the G protein Ras. We used a transgenic mouse model (synRas mice) expressing constitutively activated G12V-Harvey Ras selectively in differentiated neurons to investigate the possible effects onto neurogenesis. H-Ras activation in neurons attenuates hippocampal precursor cell generation at an early stage of the proliferative cascade before neuronal lineage determination occurs. Therefore it is unlikely that the transgenically activated H-Ras in neurons mediates this effect by a direct, intracellular signaling mechanism. Voluntary exercise restores neurogenesis up to wild type level presumably mediated by brain-derived neurotrophic factor. Reduced neurogenesis is linked to impairments in spatial short-term memory and object recognition, the latter can be rescued by voluntary exercise, as well. These data support the view that new cells significantly increase complexity that can be processed by the hippocampal network when experience requires high demands to associate stimuli over time and/or space.

  15. Two tetrodotoxin-resistant sodium channels in human dorsal root ganglion neurons.

    PubMed

    Dib-Hajj, S D; Tyrrell, L; Cummins, T R; Black, J A; Wood, P M; Waxman, S G

    1999-11-26

    Two tetrodotoxin-resistant (TTX-R) voltage-gated sodium channels, SNS and NaN, are preferentially expressed in small dorsal root ganglia (DRG) and trigeminal ganglia neurons, most of which are nociceptive, of rat and mouse. We report here the sequence of NaN from human DRG, and demonstrate the presence of two TTX-R currents in human DRG neurons. One current has physiological properties similar to those reported for SNS, while the other displays hyperpolarized voltage-dependence and persistent kinetics; a similar TTX-R current was recently identified in DRG neurons of sns-null mouse. Thus SNS and NaN channels appear to produce different currents in human DRG neurons. PMID:10580103

  16. PSA-NCAM is Expressed in Immature, but not Recently Generated, Neurons in the Adult Cat Cerebral Cortex Layer II

    PubMed Central

    Varea, Emilio; Belles, Maria; Vidueira, Sandra; Blasco-Ibáñez, José M.; Crespo, Carlos; Pastor, Ángel M.; Nacher, Juan

    2011-01-01

    Neuronal production persists during adulthood in the dentate gyrus and the olfactory bulb, where substantial numbers of immature neurons can be found. These cells can also be found in the paleocortex layer II of adult rodents, but in this case most of them have been generated during embryogenesis. Recent reports have described the presence of similar cells, with a wider distribution, in the cerebral cortex of adult cats and primates and have suggested that they may develop into interneurons. The objective of this study is to verify this hypothesis and to explore the origin of these immature neurons in adult cats. We have analyzed their distribution using immunohistochemical analysis of the polysialylated form of the neural cell adhesion molecule (PSA-NCAM) and their phenotype using markers of mature neurons and different interneuronal populations. Additionally, we have explored the origin of these cells administering 5′bromodeoxyuridine (5′BrdU) during adulthood. Immature neurons were widely dispersed in the cerebral cortex layers II and upper III, being specially abundant in the piriform and entorhinal cortices, in the ventral portions of the frontal and temporoparietal lobes, but relatively scarce in dorsal regions, such as the primary visual areas. Only a small fraction of PSA-NCAM expressing cells in layer II expressed the mature neuronal marker NeuN and virtually none of them expressed calcium binding proteins or neuropeptides. By contrast, most, if not all of these cells expressed the transcription factor Tbr-1, specifically expressed by pallium-derived principal neurons, but not CAMKII, a marker of mature excitatory neurons. Absence of PSA-NCAM/5′BrdU colocalization suggests that, as in rats, these cells were not generated during adulthood. Together, these results indicate that immature neurons in the adult cat cerebral cortex layer II are not recently generated and that they may differentiate into principal neurons. PMID:21415912

  17. 42 CFR 412.60 - DRG classification and weighting factors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 2 2014-10-01 2014-10-01 false DRG classification and weighting factors. 412.60 Section 412.60 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN... discharge is based, as appropriate, on the patient's age, sex, principal diagnosis (that is, the...

  18. 42 CFR 412.60 - DRG classification and weighting factors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... hospital has 60 days after the date of the notice of the initial assignment of a discharge to a DRG to... SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Basic Methodology for... weighting factors. (a) Diagnosis-related groups. CMS establishs a classification of inpatient...

  19. 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

  20. 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.

  1. 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

  2. Lithium Alters the Morphology of Neurites Regenerating from Cultured Adult Spiral Ganglion Neurons

    PubMed Central

    Shah, S. M.; Patel, C. H.; Feng, A. S.; Kollmar, R.

    2013-01-01

    The small-molecule drug lithium (as a monovalent ion) promotes neurite regeneration and functional recovery, is easy to administer, and is approved for human use to treat bipolar disorder. Lithium exerts its neuritogenic effect mainly by inhibiting glycogen synthase kinase 3, a constitutively-active serine/threonine kinase that is regulated by neurotrophin and “wingless-related MMTV integration site” (Wnt) signaling. In spiral ganglion neurons of the cochlea, the effects of lithium and the function of glycogen synthase kinase 3 have not been investigated. We, therefore, set out to test whether lithium modulates neuritogenesis from adult spiral ganglion neurons. Primary cultures of dissociated spiral ganglion neurons from adult mice were exposed to lithium at concentrations between 0 and 12.5 mM. The resulting neurite morphology and growth-cone appearance were measured in detail by using immunofluorescence microscopy and image analysis. We found that lithium altered the morphology of regenerating neurites and their growth cones in a differential, concentration-dependent fashion. Low concentrations of 0.5 to 2.5 mM (around the half-maximal inhibitory concentration for glycogen synthase kinase 3 and the recommended therapeutic serum concentration for bipolar disorder) enhanced neurite sprouting and branching. A high concentration of 12.5 mM, in contrast, slowed elongation. As the lithium concentration rose from low to high, the microtubules became increasingly disarranged and the growth cones more arborized. Our results demonstrate that lithium selectively stimulates phases of neuritogenesis that are driven by microtubule reorganization. In contrast, most other drugs that have previously been tested on spiral ganglion neurons are reported to inhibit neurite outgrowth or affect only elongation. Lithium sensitivity is a necessary, but not sufficient condition for the involvement of glycogen synthase kinase 3. Our results are, therefore, consistent with, but do not

  3. Chronic Social Stress Affects Synaptic Maturation of Newly Generated Neurons in the Adult Mouse Dentate Gyrus

    PubMed Central

    Chen, Chien-Chung; Huang, Chiung-Chun

    2016-01-01

    Background: Chronic stress has been found to suppress adult neurogenesis, but it remains unclear whether it may affect the maturation process of adult-born neurons. Here, we examined the influence of chronic social defeat stress on the morphological and electrophysiological properties of adult-born dentate granule cells at different developmental stages. Methods: Adult C57BL/6 mice were subjected to 10 days of chronic social defeat stress followed by a social interaction test 24 hours after the last defeat. Defeated mice were segregated into susceptible and unsusceptible subpopulations based on a measure of social interaction test. Combining electrophysiology with retrovirus-mediated birth-dating and labeling, we examined the impact of chronic social defeat stress on temporal regulation of synaptic plasticity of adult-born dentate granule cells along their maturation. Results: Chronic social defeat stress decreases the survival and dendritic complexity of adult-born dentate granule cells. While chronic social defeat stress doesn’t alter the intrinsic electrophysiological properties and synaptic transmission of surviving adult-born dentate granule cells, it promotes the developmental switch in synaptic N-methyl-D-aspartate receptors from predominant GluN2B- to GluN2A-containing receptors, which transform the immature synapse of adult-born dentate granule cells from one that exhibits enhanced long-term potentiation to one that has normal levels of long-term potentiation. Furthermore, chronic social defeat stress increases the level of endogenous repressor element-1 silencing transcription factor mRNA in adult-born dentate granule cells, and knockdown of the repressor element-1 silencing transcription factor in adult-born dentate granule cells rescues chronic social defeat stress-induced morphological deficits and accelerated developmental switch in synaptic N-methyl-D-aspartate receptor subunit composition. Conclusions: These results uncover a previously

  4. 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

  5. Civilian Health and Medical Program of the Uniformed Services (CHAMPUS); FY97 DRG updates--DoD. Notice of DRG revised rates.

    PubMed

    1996-10-17

    This notice provides the updated adjusted standardized amounts, DRG relative weights, outlier thresholds, and beneficiary cost-share per diem rates to be used for FY 1997 under the CHAMPUS DRG-based payment system. It also describes the changes made to the CHAMPUS DRG-based payment system in order to conform to changes made to the Medicare Prospective Payment System (PPS). PMID:10161559

  6. Civilian Health and Medical Program of the Uniformed Services (CHAMPUS); FY96 DRG updates--DoD. Notice of DRG revised rates.

    PubMed

    1995-10-01

    This notice provides the updated adjusted standardized amounts, DRG relative weights, outlier thresholds, and beneficiary cost-share per diem rates to be used for FY 1996 under the CHAMPUS DRG-based payment system. It also describes the changes made to the CHAMPUS DRG-based payment system in order to conform to changes made to the Medicare Prospective Payment System (PPS). PMID:10151660

  7. 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

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

    PubMed Central

    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

  9. Lower motor neuron degeneration and familial predisposition to colonic neoplasia in two adult siblings.

    PubMed

    Shaw, P J; Ince, P G; Slade, J; Burn, J; Cartlidge, N E

    1991-11-01

    A previously unreported association between a familial predisposition to colonic neoplasia and familial adult onset lower motor neuron (LMN) degeneration is reported. Two brothers presented at the ages of 53 and 44 years with multiple colonic adenomata and invasive colonic carcinoma respectively. Subsequently both developed a virtually identical pattern of motor neuron disease of progressive muscular atrophy type. At presentation both had LMN weakness affecting predominantly the upper limb and neck muscles. The disease progressed rapidly to involve the lower limb and bulbar musculature and both brothers died after a 15 month course. Necropsy was performed on one brother and showed pathological changes confined to the LMNs with no evidence of involvement of the pyramidal tracts or motor cortex. The combination of these diseases in two brothers may be of importance in the search for genes responsible for familial motor neuron disorders. It is suggested that a genomic search should be directed initially to the vicinity of known colon neoplasia genes, particularly 5q, 17q and 18q.

  10. Survival of adult generated hippocampal neurons is altered in circadian arrhythmic mice.

    PubMed

    Rakai, Brooke D; Chrusch, Michael J; Spanswick, Simon C; Dyck, Richard H; Antle, Michael C

    2014-01-01

    The subgranular zone of the hippocampal formation gives rise to new neurons that populate the dentate gyrus throughout life. Cells in the hippocampus exhibit rhythmic clock gene expression and the circadian clock is known to regulate the cycle of cell division in other areas of the body. These facts suggest that the circadian clock may regulate adult neurogenesis in the hippocampus as well. In the present study, neurogenesis in the hippocampal subgranular zone was examined in arrhythmic Bmal1 knockout (-KO) mice and their rhythmic heterozygous and wildtype littermates. Proliferation and survival of newly generated subgranular zone cells were examined using bromodeoxyuridine labelling, while pyknosis (a measure of cell death) and hippocampal volume were examined in cresyl violet stained sections. There was no significant difference in cellular proliferation between any of the groups, yet survival of proliferating cells, 6 weeks after the bromodeoxyuridine injection, was significantly greater in the BMAL1-KO animals. The number of pyknotic cells was significantly decreased in Bmal1-KO animals, yet hippocampal volume remained the same across genotypes. These findings suggest that while a functional circadian clock is not necessary for normal proliferation of neuronal precursor cells, the normal pruning of newly generated neurons in the hippocampus may require a functional circadian clock. PMID:24941219

  11. 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

  12. Correlation of the electrophysiological profiles and sodium channel transcripts of individual rat dorsal root ganglia neurons.

    PubMed

    Thériault, Olivier; Chahine, Mohamed

    2014-01-01

    Voltage gated sodium channels (Nav channels) play an important role in nociceptive transmission. They are intimately tied to the genesis and transmission of neuronal firing. Five different isoforms (Nav1.3, Nav1.6, Nav1.7, Nav1.8, and Nav1.9) have been linked to nociceptive responses. A change in the biophysical properties of these channels or in their expression levels occurs in different pathological pain states. However, the precise involvement of the isoforms in the genesis and transmission of nociceptive responses is unknown. The aim of the present study was to investigate the synergy between the different populations of Nav channels that give individual neurons a unique electrophysical profile. We used the patch-clamp technique in the whole-cell configuration to record Nav currents and action potentials from acutely dissociated small diameter DRG neurons (<30 μm) from adult rats. We also performed single cell qPCR on the same neurons. Our results revealed that there is a strong correlation between Nav currents and mRNA transcripts in individual neurons. A cluster analysis showed that subgroups formed by Nav channel transcripts by mRNA quantification have different biophysical properties. In addition, the firing frequency of the neurons was not affected by the relative populations of Nav channel. The synergy between populations of Nav channel in individual small diameter DRG neurons gives each neuron a unique electrophysiological profile. The Nav channel remodeling that occurs in different pathological pain states may be responsible for the sensitization of the neurons. PMID:25285069

  13. 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

  14. 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

  15. Adult AMPA GLUA1 Receptor Subunit Loss in 5-HT Neurons Results in a Specific Anxiety-Phenotype with Evidence for Dysregulation of 5-HT Neuronal Activity

    PubMed Central

    Weber, Tillmann; Vogt, Miriam A; Gartside, Sarah E; Berger, Stefan M; Lujan, Rafael; Lau, Thorsten; Herrmann, Elke; Sprengel, Rolf; Bartsch, Dusan; Gass, Peter

    2015-01-01

    Both the glutamatergic and serotonergic (5-HT) systems are implicated in the modulation of mood and anxiety. Descending cortical glutamatergic neurons regulate 5-HT neuronal activity in the midbrain raphe nuclei through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors. To analyze the functional role of GLUA1-containing AMPA receptors in serotonergic neurons, we used the Cre-ERT2/loxP-system for the conditional inactivation of the GLUA1-encoding Gria1 gene selectively in 5-HT neurons of adult mice. These Gria15-HT−/− mice exhibited a distinct anxiety phenotype but showed no alterations in locomotion, depression-like behavior, or learning and memory. Increased anxiety-related behavior was associated with significant decreases in tryptophan hydroxylase 2 (TPH2) expression and activity, and subsequent reductions in tissue levels of 5-HT, its metabolite 5-hydroxyindoleacetic acid (5-HIAA), and norepinephrine in the raphe nuclei. However, TPH2 expression and activity as well as monoamine levels were unchanged in the projection areas of 5-HT neurons. Extracellular electrophysiological recordings of 5-HT neurons revealed that, while α1-adrenoceptor-mediated excitation was unchanged, excitatory responses to AMPA were enhanced and the 5-HT1A autoreceptor-mediated inhibitory response to 5-HT was attenuated in Gria15-HT−/− mice. Our data show that a loss of GLUA1 protein in 5-HT neurons enhances AMPA receptor function and leads to multiple local molecular and neurochemical changes in the raphe nuclei that dysregulate 5-HT neuronal activity and induce anxiety-like behavior. PMID:25547714

  16. Adult AMPA GLUA1 receptor subunit loss in 5-HT neurons results in a specific anxiety-phenotype with evidence for dysregulation of 5-HT neuronal activity.

    PubMed

    Weber, Tillmann; Vogt, Miriam A; Gartside, Sarah E; Berger, Stefan M; Lujan, Rafael; Lau, Thorsten; Herrmann, Elke; Sprengel, Rolf; Bartsch, Dusan; Gass, Peter

    2015-05-01

    Both the glutamatergic and serotonergic (5-HT) systems are implicated in the modulation of mood and anxiety. Descending cortical glutamatergic neurons regulate 5-HT neuronal activity in the midbrain raphe nuclei through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors. To analyze the functional role of GLUA1-containing AMPA receptors in serotonergic neurons, we used the Cre-ERT2/loxP-system for the conditional inactivation of the GLUA1-encoding Gria1 gene selectively in 5-HT neurons of adult mice. These Gria1(5-HT-/-) mice exhibited a distinct anxiety phenotype but showed no alterations in locomotion, depression-like behavior, or learning and memory. Increased anxiety-related behavior was associated with significant decreases in tryptophan hydroxylase 2 (TPH2) expression and activity, and subsequent reductions in tissue levels of 5-HT, its metabolite 5-hydroxyindoleacetic acid (5-HIAA), and norepinephrine in the raphe nuclei. However, TPH2 expression and activity as well as monoamine levels were unchanged in the projection areas of 5-HT neurons. Extracellular electrophysiological recordings of 5-HT neurons revealed that, while α1-adrenoceptor-mediated excitation was unchanged, excitatory responses to AMPA were enhanced and the 5-HT1A autoreceptor-mediated inhibitory response to 5-HT was attenuated in Gria1(5-HT-/-) mice. Our data show that a loss of GLUA1 protein in 5-HT neurons enhances AMPA receptor function and leads to multiple local molecular and neurochemical changes in the raphe nuclei that dysregulate 5-HT neuronal activity and induce anxiety-like behavior.

  17. Adult human bone marrow stromal spheres express neuronal traits in vitro and in a rat model of Parkinson's disease

    PubMed Central

    Suon, Sokreine; Yang, Ming; Iacovitti, Lorraine

    2007-01-01

    Adult human bone marrow stromal cells (hMSCs) grown in suspension culture gave rise to spheres of neural progenitor (NP) cells, capable of expressing both dopaminergic (DA) and GABAergic (GABA) traits. After transplantation into the Parkinsonian rat, human NPs and neurons were present at 2 weeks. Although no DA neurons appeared to survive transplantation, there were abundant GABA neurons present in the graft. By 4 weeks, however, all cells had died. Finding ways to prolong survival and promote the appropriate neurotransmitter phenotype is essential if hMSCs are to be clinically useful. PMID:16828720

  18. Choosing a DRG grouper for Australia: issues and options.

    PubMed

    Reid, B; Palmer, G; Aisbett, C

    1991-01-01

    Issues surrounding the selection in late 1990 of the New York grouper as the basis for the first Australian Diagnosis Related Group (DRG) version are discussed. The methods and results are reported for a large scale empirical study to identify the effects, based on Australian data of using different groupers developed in the United States (U.S.). The various applications of the DRG system for funding, hospital management, quality assurance and utilisation review pose different requirements for the selection of a grouper. The impact of the various options on these applications is explored along with possible future developments. This paper is an abbreviated version of an interim project report presented to the Consensus Conference held in Canberra in November, 1990. More recent results have been added here. PMID:10117337

  19. Choosing a DRG grouper for Australia: issues and options.

    PubMed

    Reid, B; Palmer, G; Aisbett, C

    1991-01-01

    Issues surrounding the selection in late 1990 of the New York grouper as the basis for the first Australian Diagnosis Related Group (DRG) version are discussed. The methods and results are reported for a large scale empirical study to identify the effects, based on Australian data of using different groupers developed in the United States (U.S.). The various applications of the DRG system for funding, hospital management, quality assurance and utilisation review pose different requirements for the selection of a grouper. The impact of the various options on these applications is explored along with possible future developments. This paper is an abbreviated version of an interim project report presented to the Consensus Conference held in Canberra in November, 1990. More recent results have been added here.

  20. Orthodenticle is necessary for survival of a cluster of clonally related dopaminergic neurons in the Drosophila larval and adult brain

    PubMed Central

    2011-01-01

    Background The dopaminergic (DA) neurons present in the central brain of the Drosophila larva are spatially arranged in stereotyped groups that define clusters of bilaterally symmetrical neurons. These clusters have been classified according to anatomical criteria (position of the cell bodies within the cortex and/or projection pattern of the axonal tracts). However, information pertaining to the developmental biology, such as lineage relationship of clustered DA neurons and differential cell subtype-specific molecular markers and mechanisms of differentiation and/or survival, is currently not available. Results Using MARCM and twin-spot MARCM techniques together with anti-tyrosine hydroxylase immunoreactivity, we have analyzed the larval central brain DA neurons from a developmental point of view and determined their time of birth, their maturation into a DA neurotransmitter phenotype as well as their lineage relationships. In addition, we have found that the homeodomain containing transcription factor Orthodenticle (Otd) is present in a cluster of clonally related DA neurons in both the larval and adult brain. Taking advantage of the otd hypomorphic mutation ocelliless (oc) and the oc2-Gal4 reporter line, we have studied the involvement of orthodenticle (otd) in the survival and/or cell fate specification of these post-mitotic neurons. Conclusions Our findings provide evidence of the presence of seven neuroblast lineages responsible for the generation of the larval central brain DA neurons during embryogenesis. otd is expressed in a defined group of clonally related DA neurons from first instar larvae to adulthood, making it possible to establish an identity relationship between the larval DL2a and the adult PPL2 DA clusters. This poses otd as a lineage-specific and differential marker of a subset of clonally related DA neurons. Finally, we show that otd is required in those DA neurons for their survival. PMID:21999236

  1. Neuronal somatic ATP release triggers neuron-satellite glial cell communication in dorsal root ganglia.

    PubMed

    Zhang, X; Chen, Y; Wang, C; Huang, L-Y M

    2007-06-01

    It has been generally assumed that the cell body (soma) of a neuron, which contains the nucleus, is mainly responsible for synthesis of macromolecules and has a limited role in cell-to-cell communication. Using sniffer patch recordings, we show here that electrical stimulation of dorsal root ganglion (DRG) neurons elicits robust vesicular ATP release from their somata. The rate of release events increases with the frequency of nerve stimulation; external Ca(2+) entry is required for the release. FM1-43 photoconversion analysis further reveals that small clear vesicles participate in exocytosis. In addition, the released ATP activates P2X7 receptors in satellite cells that enwrap each DRG neuron and triggers the communication between neuronal somata and glial cells. Blocking L-type Ca(2+) channels completely eliminates the neuron-glia communication. We further show that activation of P2X7 receptors can lead to the release of tumor necrosis factor-alpha (TNFalpha) from satellite cells. TNFalpha in turn potentiates the P2X3 receptor-mediated responses and increases the excitability of DRG neurons. This study provides strong evidence that somata of DRG neurons actively release transmitters and play a crucial role in bidirectional communication between neurons and surrounding satellite glial cells. These results also suggest that, contrary to the conventional view, neuronal somata have a significant role in cell-cell signaling.

  2. Action of thymol on spontaneous excitatory transmission in adult rat spinal substantia gelatinosa neurons.

    PubMed

    Xu, Zhi-Hao; Wang, Chong; Fujita, Tsugumi; Jiang, Chang-Yu; Kumamoto, Eiichi

    2015-10-01

    Thymol, which is contained in thyme essential oil, has various actions including antinociception and nerve conduction inhibition. Although thymol activates transient receptor potential (TRP) channels expressed in heterologous cells, it remains to be examined whether this is so in native neurons. It has not yet been examined how thymol affects synaptic transmission. In order to know how thymol modulates excitatory transmission with a focus on TRP activation, we investigated its effect on glutamatergic spontaneous excitatory transmission in lamina II (substantia gelatinosa; SG) neurons with which nerve terminals expressing TRP channels make synaptic contacts. The experiment was performed by using the blind whole-cell patch-clamp technique in adult rat spinal cord slices. Superfusing thymol (1 mM) for 3 min reversibly increased the frequency of spontaneous excitatory postsynaptic current (sEPSC) with a minimal increase in its amplitude in all neurons examined. Seventy-seven% of the neurons produced an outward current at a holding potential of -70 mV. The sEPSC frequency increase and outward current produced by thymol were concentration-dependent with almost the same half-maximal effective concentration (EC50) values of 0.18 and 0.14 mM, respectively. These activities were repeated at a time interval of 30 min, although the sEPSC frequency increase but not outward current recovered with a slow time course. Voltage-gated Na(+)-channel blocker tetrodotoxin did not affect the thymol activities. The sEPSC frequency increase was inhibited by TRPA1 antagonist HC-030031 but not TRPV1 and TRPM8 antagonist (capsazepine and BCTC, respectively), while these antagonists had no effect on the outward current. This was so, albeit the two thymol activities had similar EC50 values. It is concluded that thymol increases the spontaneous release of L-glutamate onto SG neurons by activating TRPA1 channels while producing an outward current without TRP activation. Considering that the SG

  3. 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

  4. [Quantitative analysis of the isthmo-optic nucleus and projection neurons to the retina in adult fowl (Gallus gallus domesticus)].

    PubMed

    Sugita, S; Yamada, M

    1992-08-01

    Quantitative analysis of the isthmo-optic nucleus (IO) and centrifugal projection to the retina in the fowl was made using Nissl preparation and retrograde horseradish peroxidase (HRP) methods. Seven adult fowls (Gallus gallus domesticus) were used for Nissl stain. Serial sections were cut on a freezing microtome at 60 microns and stained with cresyl violet. IO was situated just medial to the caudal part of the tectum and laterodorsal surface of the brain stem. Rostrocaudal extension of IO was about 800-1,000 microns. The average total volume and neuronal population of the IO was 280 x 10(-3) mm3 and 5,600 neurons, respectively. Eight animals were used for HRP study. One hundred microliters of 30% HRP solution in physiological saline was injected into the vitreous body of one eye of each hen. Serial transverse sections of 60 microns were treated with tetramethyl benzidine (TMB). Many labeled neurons were found in contralateral brain stem. Average total number of contralateral HRP-labeled cells in IO and peri-IO were 5,268 and 1,492, respectively. Labeled neurons peri-IO were mainly distributed ventrally and rostrally to IO. No labeled neurons in IO, and only a few labeled neurons peri-IO were found ipsilaterally. The number of HRP-labeled neurons in IO corresponded to the neuronal population of IO in Nissl preparation, which suggested that most of isthmo-optic neurons might be projecting to the contralateral retina. In contrast to the round and small IO neurons (long axis 15-20 microns, short axis 10-20 microns), peri-IO neurons were multipolar and longer (long axis 15-30 microns, short axis 10-25 microns).

  5. Interstitial cells of the adult neocortical white matter are the remnant of the early generated subplate neuron population

    SciTech Connect

    Chun, J.J.; Shatz, C.J.

    1989-04-22

    The postnatal fate of the first-generated neurons of the cat cerebral cortex was examined. These neurons can be identified uniquely by 3H-thymidine exposure during the week preceding the neurogenesis of cortical layer 6. Previous studies in which 3H-thymidine birthdating at embryonic day 27 (E27) was combined with immunohistochemistry have shown that these neurons are present in large numbers during fetal and early postnatal life within the subplate (future white matter), that they are immunoreactive for the neuron-specific protein MAP2 and for the putative neurotransmitters GABA, NPY, SRIF, and CCK. Here, the same techniques were used to follow the postnatal location and disappearance of the early generated subplate neuron population. At birth (P0), subplate neurons showing immunoreactivity for GABA, NPY, SRIF, or CCK are present in large numbers and at high density within the white matter throughout the neocortex, and the entire population can be observed as a dense MAP2-immunoreactive band situated beneath cortical layer 6. Between P0 and P401 (adulthood), the MAP2-immunostained band disappears so that comparatively few MAP2-immunoreactive neurons remain within the white matter. There is a corresponding decrease in the number and density of neurons stained with antibodies against neurotransmitters. In each instance, these neurons could be double-labeled by the administration of 3H-thymidine at E27, indicating that they are the remnants of the early generated subplate neuron population. The major period of decrease occurs during the first 4 postnatal weeks, and adult values are attained by 5 months. Within the white matter of the lateral gyrus (visual cortex), the density of immunostained neurons decreases dramatically: MAP2, 82%, SRIF, 81%, and NPY, 96%.

  6. Projection neurons in the cortex and hippocampus: differential effects of chronic khat and ethanol exposure in adult male rats

    PubMed Central

    Alele, Paul E; Matovu, Daniel; Imanirampa, Lawrence; Ajayi, Abayomi M; Kasule, Gyaviira T

    2016-01-01

    Background Recent evidence suggests that many individuals who chew khat recreationally also drink ethanol to offset the stimulating effect of khat. The objective of this study was to describe the separate and interactive effects of chronic ethanol and khat exposure on key projection neurons in the cortex and hippocampus of young adult male rats. Methods Young adult male Sprague Dawley rats were divided into six treatment groups: 2 g/kg khat, 4 g/kg khat, 4 g/kg ethanol, combined khat and ethanol (4 g/kg each), a normal saline control, and an untreated group. Treatments were administered orally for 28 continuous days; brains were then harvested, sectioned, and routine hematoxylin–eosin staining was done. Following photomicrography, ImageJ® software captured data regarding neuron number and size. Results No differences occurred in counts of both granular and pyramidal projection neurons in the motor cortex and all four subfields of the hippocampal formation. Khat dose-dependently increased pyramidal neuron size in the motor cortex and the CA3 region, but had different effects on granular neuron size in the dentate gyrus and the motor cortex. Mean pyramidal neuron size for the ethanol-only treatment was larger than that for the 2 g/kg khat group, and the saline control group, in CA3 and in the motor cortex. Concomitant khat and ethanol increased granular neuron size in the motor cortex, compared to the 2 g/kg khat group, the 4 g/kg khat group, and the 4 g/kg ethanol group. In the CA3 region, the 4 g/kg ethanol group showed a larger mean pyramidal neuron size than the combined khat and ethanol group. Conclusion These results suggest that concomitant khat and ethanol exposure changes granular and pyramidal projection neuron sizes differentially in the motor cortex and hippocampus, compared to the effects of chronic exposure to these two drugs separately. PMID:27785113

  7. 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

  8. 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…

  9. 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

  10. 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

  11. Secreted Semaphorins from Degenerating Larval ORN Axons Direct Adult Projection Neuron Dendrite Targeting

    PubMed Central

    Sweeney, Lora B.; Chou, Ya-Hui; Wu, Zhuhao; Joo, William; Komiyama, Takaki; Potter, Christopher J.; Kolodkin, Alex L.; Garcia, K. Christopher; Luo, Liqun

    2012-01-01

    SUMMARY During assembly of the Drosophila olfactory circuit, projection neuron (PN) dendrites pre-pattern the developing antennal lobe before the arrival of axons from their presynaptic partners, the adult olfactory receptor neurons (ORNs). We previously found that levels of transmembrane Semaphorin-1a, which acts as a receptor, instruct PN dendrite targeting along the dorsolateral-ventromedial axis. Here we show that two secreted semaphorins, Sema-2a and Sema-2b, provide spatial cues for PN dendrite targeting. Sema-2a and Sema-2b proteins are distributed in gradients opposing the Sema-1a protein gradient, and Sema-1a binds to Sema-2a-expressing cells. In Sema-2a and Sema-2b double mutants, PN dendrites that normally target dorsolaterally in the antennal lobe mistarget ventromedially, phenocopying cell-autonomous Sema-1a removal from these PNs. Cell ablation, cell-specific knockdown, and rescue experiments indicate that secreted semaphorins from degenerating larval ORN axons direct dendrite targeting. Thus, a degenerating brain structure instructs the wiring of a developing circuit through the repulsive action of secreted semaphorins. PMID:22153371

  12. Adult plasticity in multisensory neurons: Short-term experience-dependent changes in the superior colliculus

    PubMed Central

    Yu, Liping; Stein, Barry E.; Rowland, Benjamin A.

    2010-01-01

    Multisensory neurons in the superior colliculus (SC) have the capability to integrate signals that belong to the same event, despite being conveyed by different senses. They develop this capability during early life as experience is gained with the statistics of cross-modal events. These adaptations prepare the SC to deal with the cross-modal events that are likely to be encountered throughout life. Here we found that neurons in the adult SC can also adapt to experience with sequentially-ordered cross-modal (visual-auditory or auditory-visual) cues, and that they do so over short periods of time (minutes), as if adapting to a particular stimulus configuration. This short-term plasticity was evident as a rapid increase in the magnitude and duration of responses to the first stimulus, and a shortening of the latency and increase in magnitude of the responses to the second stimulus when they are presented in sequence. The result was that the two responses appeared to merge. These changes were stable in the absence of experience with competing stimulus configurations, outlasted the exposure period, and could not be induced by equivalent experience with sequential within-modal (visual-visual or auditory-auditory) stimuli. A parsimonious interpretation is that the additional SC activity provided by the second stimulus became associated with, and increased the potency of, the afferents responding to the preceding stimulus. This interpretation is consistent with the principle of spike-timing dependent plasticity (STDP), which may provide the basic mechanism for short term or long term plasticity and be operative in both the adult and neonatal SC. PMID:20016107

  13. HETEROTOPICALLY TRANSPLANTED CVO NEURAL STEM CELLS GENERATE NEURONS AND MIGRATE WITH SVZ CELLS IN THE ADULT MOUSE BRAIN

    PubMed Central

    Bennett, Lori B.; Cai, Jingli; Enikolopov, Grigori; Iacovitti, Lorraine

    2010-01-01

    Production of new neurons throughout adulthood has been well characterized in two brain regions, the subventricular zone (SVZ) of the anterolateral ventricle and the subgranular zone (SGZ) of the hippocampus. The neurons produced from these regions arise from neural stem cells (NSCs) found in highly regulated stem cell niches. We recently showed that midline structures called circumventricular organs (CVOs) also contain NSCs capable of neurogenesis and/or astrogliogenesis in vitro and in situ [3]. The present study demonstrates that NSCs derived from two astrogliogenic CVOs, the median eminence and organum vasculosum of the lamina terminalis of the Nestin-GFP mouse, possess the potential to integrate into the SVZ and differentiate into cells with a neuronal phenotype. These NSCs, following expansion and BrdU-labeling in culture and heterotopic transplantation into a region proximal to the SVZ in adult mice, migrate caudally to the SVZ and express early neuronal markers (TUC-4, PSA-NCAM) as they migrate along the rostral migratory stream. CVO-derived BrdU+ cells ultimately reach the olfactory bulb where they express early (PSA-NCAM) and mature (NeuN) neuronal markers. Collectively, these data suggest that although NSCs derived from the ME and OVLT CVOs are astrogliogenic in situ, they produce cells phenotypic of neurons in vivo when placed in a neurogenic environment. These findings may have implications for neural repair in the adult brain. PMID:20298755

  14. 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.

  15. Functional Implications of miR-19 in the Migration of Newborn Neurons in the Adult Brain.

    PubMed

    Han, Jinju; Kim, Hyung Joon; Schafer, Simon T; Paquola, Apua; Clemenson, Gregory D; Toda, Tomohisa; Oh, Jinseo; Pankonin, Aimee R; Lee, Bo Suk; Johnston, Stephen T; Sarkar, Anindita; Denli, Ahmet M; Gage, Fred H

    2016-07-01

    Altered microRNA profiles have been implicated in human brain disorders. However, the functional contribution of individual microRNAs to neuronal development and function is largely unknown. Here, we report biological functions for miR-19 in adult neurogenesis. We determined that miR-19 is enriched in neural progenitor cells (NPCs) and downregulated during neuronal development in the adult hippocampus. By manipulating miR-19 in NPCs for gain- and loss-of-function studies, we discovered that miR-19 regulates cell migration by directly targeting Rapgef2. Concordantly, dysregulation of miR-19 in NPCs alters the positioning of newborn neurons in the adult brain. Furthermore, we found abnormal expression of miR-19 in human NPCs generated from schizophrenic patient-derived induced pluripotent stem cells (iPSCs) that have been described as displaying aberrant migration. Our study demonstrates the significance of posttranscriptional gene regulation by miR-19 in preventing the irregular migration of adult-born neurons that may contribute to the etiology of schizophrenia. PMID:27387650

  16. 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

  17. [Effect of spontaneous firing of injured dorsal root ganglion neuron on excitability of wide dynamic range neuron in rat spinal dorsal horn].

    PubMed

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

    2013-10-25

    The aim of the paper is to study the effect of spontaneous firing of injured dorsal root ganglion (DRG) neuron in chronic compression of DRG (CCD) model on excitability of wide dynamic range (WDR) neuron in rat spinal dorsal horn. In vivo intracellular recording was done in DRG neurons and in vivo extracellular recording was done in spinal WDR neurons. After CCD, incidence of spontaneous discharge and firing frequency enhanced to 59.46% and (4.30 ± 0.69) Hz respectively from 22.81% and (0.60 ± 0.08) Hz in normal control group (P < 0.05). Local administration of 50 nmol/L tetrodotoxin (TTX) on DRG neuron in CCD rats decreased the spontaneous activities of WDR neurons from (191.97 ± 45.20)/min to (92.50 ± 30.32)/min (P < 0.05). On the other side, local administration of 100 mmol/L KCl on DRG neuron evoked spontaneous firing in a reversible way (n = 5) in silent WDR neurons of normal rats. There was 36.36% (12/33) WDR neuron showing after-discharge in response to innocuous mechanical stimuli on cutaneous receptive field in CCD rats, while after-discharge was not seen in control rats. Local administration of TTX on DRG with a concentration of 50 nmol/L attenuated innocuous electric stimuli-evoked after-discharge of WDR neurons in CCD rats in a reversible manner, and the frequency was decreased from (263 ± 56.5) Hz to (117 ± 30) Hz (P < 0.05). The study suggests that the excitability of WDR neurons is influenced by spontaneous firings of DRG neurons after CCD.

  18. NR2B Expression in Rat DRG Is Differentially Regulated Following Peripheral Nerve Injuries That Lead to Transient or Sustained Stimuli-Evoked Hypersensitivity

    PubMed Central

    Norcini, Monica; Sideris, Alexandra; Adler, Samantha M.; Hernandez, Lourdes A. M.; Zhang, Jin; Blanck, Thomas J. J.; Recio-Pinto, Esperanza

    2016-01-01

    Following injury, primary sensory neurons undergo changes that drive central sensitization and contribute to the maintenance of persistent hypersensitivity. NR2B expression in the dorsal root ganglia (DRG) has not been previously examined in neuropathic pain models. Here, we investigated if changes in NR2B expression within the DRG are associated with hypersensitivities that result from peripheral nerve injuries. This was done by comparing the NR2B expression in the DRG derived from two modalities of the spared nerve injury (SNI) model, since each variant produces different neuropathic pain phenotypes. Using the electronic von Frey to stimulate the spared and non-spared regions of the hindpaws, we demonstrated that sural-SNI animals develop sustained neuropathic pain in both regions while the tibial-SNI animals recover. NR2B expression was measured at Day 23 and Day 86 post-injury. At Day 23 and 86 post-injury, sural-SNI animals display strong hypersensitivity, whereas tibial-SNI animals display 50 and 100% recovery from post-injury-induced hypersensitivity, respectively. In tibial-SNI at Day 86, but not at Day 23 the perinuclear region of the neuronal somata displayed an increase in NR2B protein. This retention of NR2B protein within the perinuclear region, which will render them non-functional, correlates with the recovery observed in tibial-SNI. In sural-SNI at Day 86, DRG displayed an increase in NR2B mRNA which correlates with the development of sustained hypersensitivity in this model. The increase in NR2B mRNA was not associated with an increase in NR2B protein within the neuronal somata. The latter may result from a decrease in kinesin Kif17, since Kif17 mediates NR2B transport to the soma’s plasma membrane. In both SNIs, microglia/macrophages showed a transient increase in NR2B protein detected at Day 23 but not at Day 86, which correlates with the initial post-injury induced hypersensitivity in both SNIs. In tibial-SNI at Day 86, but not at Day 23

  19. Neuropathologic and biochemical changes during disease progression in liver X receptor beta-/- mice, a model of adult neuron disease.

    PubMed

    Bigini, Paolo; Steffensen, Knut R; Ferrario, Anna; Diomede, Luisa; Ferrara, Giovanni; Barbera, Sara; Salzano, Sonia; Fumagalli, Elena; Ghezzi, Pietro; Mennini, Tiziana; Gustafsson, Jan-Ake

    2010-06-01

    In amyotrophic lateral sclerosis (ALS), there is selective degeneration of motor neurons that leads to paralysis and death. Although the etiology of ALS is unclear, its heterogeneity suggests that a combination of factors (endogenous and/or environmental) may induce progressive motor neuron stress that results in the activation of different cell death pathways. Alterations of brain cholesterol homeostasis have recently been considered as possible cofactors in many neurodegenerative disorders, including ALS. The liver X receptor beta (LXRbeta) receptor is involved in lipogenesis and cholesterol metabolism, and we previously found that adult-onset motor neuron pathology occurs in LXRbeta mice. Here, we investigated neuromuscular alterations of LXRbeta mice from ages 3 to 24 months. Increased cholesterol levels, gliosis, and inflammation preceded motor neuron loss and clinical disease onset; the mice showed progressivemotor neuron deficits starting from age 7 months. The numbers ofmotor neurons and neuromuscular junctions were decreased in 24-month-old mice, but neither paralysis nor reduced life span was observed. Moreover, other spinal neurons were also lost in these mice. These results suggest that LXRbeta may inhibit neuroinflammation and maintain cholesterol homeostasis, and that LXRbeta mice represent a potential model for investigating the role of cholesterol in ALS and other neurodegenerative disorders.

  20. Genetic control of adult neurogenesis: interplay of differentiation, proliferation and survival modulates new neurons function, and memory circuits

    PubMed Central

    Tirone, Felice; Farioli-Vecchioli, Stefano; Micheli, Laura; Ceccarelli, Manuela; Leonardi, Luca

    2013-01-01

    Within the hippocampal circuitry, the basic function of the dentate gyrus is to transform the memory input coming from the enthorinal cortex into sparse and categorized outputs to CA3, in this way separating related memory information. New neurons generated in the dentate gyrus during adulthood appear to facilitate this process, allowing a better separation between closely spaced memories (pattern separation). The evidence underlying this model has been gathered essentially by ablating the newly adult-generated neurons. This approach, however, does not allow monitoring of the integration of new neurons into memory circuits and is likely to set in motion compensatory circuits, possibly leading to an underestimation of the role of new neurons. Here we review the background of the basic function of the hippocampus and of the known properties of new adult-generated neurons. In this context, we analyze the cognitive performance in mouse models generated by us and others, with modified expression of the genes Btg2 (PC3/Tis21), Btg1, Pten, BMP4, etc., where new neurons underwent a change in their differentiation rate or a partial decrease of their proliferation or survival rate rather than ablation. The effects of these modifications are equal or greater than full ablation, suggesting that the architecture of circuits, as it unfolds from the interaction between existing and new neurons, can have a greater functional impact than the sheer number of new neurons. We propose a model which attempts to measure and correlate the set of cellular changes in the process of neurogenesis with the memory function. PMID:23734097

  1. 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

  2. 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

    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

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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

  8. Adult-like complexity of the larval antennal lobe of D. melanogaster despite markedly low numbers of odorant receptor neurons.

    PubMed

    Python, François; Stocker, Reinhard F

    2002-04-15

    We provide a detailed analysis of the larval head chemosensory system of Drosophila melanogaster, based on confocal microscopy of cell-specific reporter gene expression in P[GAL4] enhancer trap lines. In particular, we describe the neuronal composition of three external and three pharyngeal chemosensory organs, the nerve tracts chosen by their afferents, and their central target regions. With a total of 21 olfactory and 80 gustatory neurons, the sensory level is numerically much simpler than that of the adult. Moreover, its design is different than in the adult, showing an association between smell and taste sensilla. In contrast, the first-order relay of the olfactory afferents, the larval antennal lobe (LAL), exhibits adult-like features both in terms of structure and cell number. It shows a division into approximately 30 subunits, reminiscent of glomeruli in the adult antennal lobe. Taken together, the design of the larval chemosensory system is a "hybrid," with larval-specific features in the periphery and central characteristics in common with the adult. The largely reduced numbers of afferents and the similar architecture of the LAL and the adult antennal lobe, render the larval chemosensory system of Drosophila a valuable model system, both for studying smell and taste and for examining the development of its adult organization.

  9. 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

  10. 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

  11. Glutamine Synthetase is Expressed by Primary Sensory Neurons from Chick Embryos In Vitro but not In Vivo: Influence of Skeletal Muscle Extract.

    PubMed

    Barakat-Walter, I.; Droz, B.

    1990-01-01

    Glutamine synthetase (GS) catalyses the ATP-dependent formation of glutamine from glutamate and ammonia. To determine whether dorsal root ganglion (DRG) cells from chick embryos express the enzyme in vivo or in vitro, GS was detected by immunocytochemical reaction either in vibratome sections of DRG or in dissociated DRG cell cultures. The immunocytochemical detection of GS showed that in vivo the DRG taken from chick embryos at day 10 (E10), E14, E18 or from chickens after hatching were free of any GS-positive ganglion cells; in contrast, in neuron-enriched cultures of DRG cells grown in vitro at E10, virtually all the neuronal cells (98.6 +/- 1.0%) express GS at 3, 5 or 7 days of culture. In mixed DRG cell cultures, only 83.6+/-4.6% of the neurons displayed a GS-immunoreactivity. In both culture conditions, neither the presence of horse serum nor the age of the culture appeared to affect the percentage of neurons which displayed a GS-immunoreactivity. After [3H]glutamine uptake, radioautographs revealed that only 80% of the neurons were labelled in neuron-enriched DRG cell cultures while 96% of the neurons were radioactive in mixed DRG cell cultures. Furthermore the most heavily [3H]glutamine-labelled neurons were exclusively found in mixed DRG cell cultures. Combination of both immunocytochemical detection of GS and radioautography after [3H]glutamine uptake showed that strongly GS-immunostained neurons corresponded to poorly radioactive ones and vice versa. When skeletal muscle extract (ME) was added to DRG cell cultures, the number of GS-positive neurons was reduced to 77.5 +/- 2.5% in neuron-enriched cultures or to 43.6 +/- 3.8% in mixed DRG cell cultures; in both types of culture, the intensity of the neuronal immunostaining was depressed. Furthermore, combined action of ME and non-neuronal cells potentiates the enzyme repression exerted separately by ME or non-neuronal cells. Since GS-immunoreactivity is expressed in DRG cells grown in vitro, but not in

  12. 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

    2011-03-09

    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.

  13. 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

  14. Transgenic neuronal nitric oxide synthase expression induces axotomy-like changes in adult motoneurons.

    PubMed

    Montero, Fernando; Sunico, Carmen R; Liu, Behui; Paton, Julian F R; Kasparov, Sergey; Moreno-López, Bernardo

    2010-09-15

    Dysregulation of protein expression, function and/or aggregation is a hallmark of a number of neuropathological conditions. Among them, upregulation and/or de novo expression of the neuronal isoform of nitric oxide (NO) synthase (nNOS) commonly occurs in diverse neurodegenerative diseases and in axotomized motoneurons. We used adenoviral (AVV) and lentiviral (LVV) vectors to study the effects of de novo nNOS expression on the functional properties and synaptic array of motoneurons. AVV-nNOS injection into the genioglossus muscle retrogradely transduced neonatal hypoglossal motoneurons (HMNs). Ratiometric real-time NO imaging confirmed that transduced HMNs generated NO gradients in brain parenchyma (space constant: 12.3 μm) in response to a glutamatergic stimulus. Unilateral AVV-nNOS microinjection in the hypoglossal nucleus of adult rats induced axotomy-like changes in HMNs. Specifically, we found alterations in axonal conduction properties and the recruitment order of motor units and reductions in responsiveness to synaptic drive and in the linear density of synaptophysin-positive puncta opposed to HMN somata. Functional alterations were fully prevented by chronic treatment with nNOS or soluble guanylyl cyclase inhibitors. Synaptic and functional changes were also completely avoided by prior intranuclear injection of a neuron-specific LVV system for miRNA-mediated nNOS knock-down (LVV-miR-shRNA/nNOS). Furthermore, synaptic and several functional changes evoked by XIIth nerve injury were to a large extent prevented by intranuclear administration of LVV-miR-shRNA/nNOS. We suggest that nNOS up-regulation creates a repulsive NO gradient for synaptic boutons underlying most of the functional impairment undergone by injured motoneurons. This further strengthens the case for nNOS targeting as a plausible strategy for treatment of peripheral neuropathies and neurodegenerative disorders.

  15. Transgenic neuronal nitric oxide synthase expression induces axotomy-like changes in adult motoneurons

    PubMed Central

    Montero, Fernando; Sunico, Carmen R; Liu, Behui; Paton, Julian F R; Kasparov, Sergey; Moreno-López, Bernardo

    2010-01-01

    Dysregulation of protein expression, function and/or aggregation is a hallmark of a number of neuropathological conditions. Among them, upregulation and/or de novo expression of the neuronal isoform of nitric oxide (NO) synthase (nNOS) commonly occurs in diverse neurodegenerative diseases and in axotomized motoneurons. We used adenoviral (AVV) and lentiviral (LVV) vectors to study the effects of de novo nNOS expression on the functional properties and synaptic array of motoneurons. AVV-nNOS injection into the genioglossus muscle retrogradely transduced neonatal hypoglossal motoneurons (HMNs). Ratiometric real-time NO imaging confirmed that transduced HMNs generated NO gradients in brain parenchyma (space constant: ∼12.3 μm) in response to a glutamatergic stimulus. Unilateral AVV-nNOS microinjection in the hypoglossal nucleus of adult rats induced axotomy-like changes in HMNs. Specifically, we found alterations in axonal conduction properties and the recruitment order of motor units and reductions in responsiveness to synaptic drive and in the linear density of synaptophysin-positive puncta opposed to HMN somata. Functional alterations were fully prevented by chronic treatment with nNOS or soluble guanylyl cyclase inhibitors. Synaptic and functional changes were also completely avoided by prior intranuclear injection of a neuron-specific LVV system for miRNA-mediated nNOS knock-down (LVV-miR-shRNA/nNOS). Furthermore, synaptic and several functional changes evoked by XIIth nerve injury were to a large extent prevented by intranuclear administration of LVV-miR-shRNA/nNOS. We suggest that nNOS up-regulation creates a repulsive NO gradient for synaptic boutons underlying most of the functional impairment undergone by injured motoneurons. This further strengthens the case for nNOS targeting as a plausible strategy for treatment of peripheral neuropaties and neurodegenerative disorders. PMID:20660560

  16. 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.

  17. 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

  18. Morphological analysis of activity-reduced adult-born neurons in the mouse olfactory bulb.

    PubMed

    Dahlen, Jeffrey E; Jimenez, Daniel A; Gerkin, Richard C; Urban, Nathan N

    2011-01-01

    Adult-born neurons (ABNs) are added to the olfactory bulb (OB) throughout life in rodents. While many factors have been identified as regulating the survival and integration of ABNs into existing circuitry, the understanding of how these factors affect ABN morphology and connectivity is limited. Here we compare how cell intrinsic [small interfering RNA (siRNA) knock-down of voltage gated sodium channels Na(V)1.1-1.3] and circuit level (naris occlusion) reductions in activity affect ABN morphology during integration into the OB. We found that both manipulations reduce the number of dendritic spines (and thus likely the number of reciprocal synaptic connections) formed with the surrounding circuitry and inhibited dendritic ramification of ABNs. Further, we identified regions of ABN apical dendrites where the largest and most significant decreases occur following siRNA knock-down or naris occlusion. In siRNA knock-down cells, reduction of spines is observed in proximal regions of the apical dendrite. This suggests that distal regions of the dendrite may remain active independent of Na(V)1.1-1.3 channel expression, perhaps facilitated by activation of T-type calcium channels and NMDA receptors. By contrast, circuit level reduction of activity by naris occlusion resulted in a global depression of spine number. Together, these results indicate that ABNs retain the ability to develop their typical overall morphological features regardless of experienced activity, and activity modulates the number and location of formed connections.

  19. Mutated CTSF in adult-onset neuronal ceroid lipofuscinosis and FTD

    PubMed Central

    van der Zee, Julie; Mariën, Peter; Crols, Roeland; Van Mossevelde, Sara; Dillen, Lubina; Perrone, Federica; Engelborghs, Sebastiaan; Verhoeven, Jo; D'aes, Tine; Ceuterick-De Groote, Chantal; Sieben, Anne; Versijpt, Jan; Cras, Patrick; Martin, Jean-Jacques

    2016-01-01

    Objective: To investigate the molecular basis of a Belgian family with autosomal recessive adult-onset neuronal ceroid lipofuscinosis (ANCL or Kufs disease [KD]) with pronounced frontal lobe involvement and to expand the findings to a cohort of unrelated Belgian patients with frontotemporal dementia (FTD). Methods: Genetic screening in the ANCL family and FTD cohort (n = 461) was performed using exome sequencing and targeted massive parallel resequencing. Results: We identified a homozygous mutation (p.Ile404Thr) in the Cathepsin F (CTSF) gene cosegregating in the ANCL family. No other mutations were found that could explain the disease in this family. All 4 affected sibs developed motor symptoms and early-onset dementia with prominent frontal features. Two of them evolved to akinetic mutism. Disease presentation showed marked phenotypic variation with the onset ranging from 26 to 50 years. Myoclonic epilepsy in one of the sibs was suggestive for KD type A, while epilepsy was not present in the other sibs who presented with clinical features of KD type B. In a Belgian cohort of unrelated patients with FTD, the same heterozygous p.Arg245His mutation was identified in 2 patients who shared a common haplotype. Conclusions: A homozygous CTSF mutation was identified in a recessive ANCL pedigree. In contrast to the previous associations of CTSF with KD type B, our findings suggest that CTSF genetic testing should also be considered in patients with KD type A as well as in early-onset dementia with prominent frontal lobe and motor symptoms.

  20. 42 CFR 478.15 - QIO review of changes resulting from DRG validation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false QIO review of changes resulting from DRG validation... review of changes resulting from DRG validation. (a) General rules. (1) A provider or practitioner dissatisfied with a change to the diagnostic or procedural coding information made by a QIO as a result of...

  1. 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 dissatisfied with a change to the diagnostic or procedural coding information made by a QIO as a result of...

  2. 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…

  3. 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 under part 473 of this chapter for changes in diagnostic and procedural coding that resulted in a...

  4. 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... § 476.84 Changes as a result of DRG validation. A provider or practitioner may obtain a review by a QIO under part 473 of this chapter for changes in diagnostic and procedural coding that resulted in a...

  5. 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... § 476.84 Changes as a result of DRG validation. A provider or practitioner may obtain a review by a QIO under part 473 of this chapter for changes in diagnostic and procedural coding that resulted in a...

  6. 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...

  7. Neuronal Subtype and Satellite Cell Tropism Are Determinants of Varicella-Zoster Virus Virulence in Human Dorsal Root Ganglia Xenografts In Vivo

    PubMed Central

    Zerboni, Leigh; Arvin, Ann

    2015-01-01

    Varicella zoster virus (VZV), a human alphaherpesvirus, causes varicella during primary infection. VZV reactivation from neuronal latency may cause herpes zoster, post herpetic neuralgia (PHN) and other neurologic syndromes. To investigate VZV neuropathogenesis, we developed a model using human dorsal root ganglia (DRG) xenografts in immunodeficient (SCID) mice. The SCID DRG model provides an opportunity to examine characteristics of VZV infection that occur in the context of the specialized architecture of DRG, in which nerve cell bodies are ensheathed by satellite glial cells (SGC) which support neuronal homeostasis. We hypothesized that VZV exhibits neuron-subtype specific tropism and that VZV tropism for SGC contributes to VZV-related ganglionopathy. Based on quantitative analyses of viral and cell protein expression in DRG tissue sections, we demonstrated that, whereas DRG neurons had an immature neuronal phenotype prior to implantation, subtype heterogeneity was observed within 20 weeks and SGC retained the capacity to maintain neuronal homeostasis longterm. Profiling VZV protein expression in DRG neurons showed that VZV enters peripherin+ nociceptive and RT97+ mechanoreceptive neurons by both axonal transport and contiguous spread from SGC, but replication in RT97+ neurons is blocked. Restriction occurs even when the SGC surrounding the neuronal cell body were infected and after entry and ORF61 expression, but before IE62 or IE63 protein expression. Notably, although contiguous VZV spread with loss of SGC support would be predicted to affect survival of both nociceptive and mechanoreceptive neurons, RT97+ neurons showed selective loss relative to peripherin+ neurons at later times in DRG infection. Profiling cell factors that were upregulated in VZV-infected DRG indicated that VZV infection induced marked pro-inflammatory responses, as well as proteins of the interferon pathway and neuroprotective responses. These neuropathologic changes observed in sensory

  8. Tetrodotoxin-resistant sodium channels in sensory neurons generate slow resurgent currents that are enhanced by inflammatory mediators.

    PubMed

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

    2014-05-21

    Resurgent sodium currents contribute to the regeneration of action potentials and enhanced neuronal excitability. Tetrodotoxin-sensitive (TTX-S) resurgent currents have been described in many different neuron populations, including cerebellar and dorsal root ganglia (DRG) neurons. In most cases, sodium channel Nav1.6 is the major contributor to these TTX-S resurgent currents. Here we report a novel TTX-resistant (TTX-R) resurgent current recorded from rat DRG neurons. The TTX-R resurgent currents are similar to classic TTX-S resurgent currents in many respects, but not all. As with TTX-S resurgent currents, they are activated by membrane repolarization, inhibited by lidocaine, and enhanced by a peptide-mimetic of the β4 sodium channel subunit intracellular domain. However, the TTX-R resurgent currents exhibit much slower kinetics, occur at more depolarized voltages, and are sensitive to the Nav1.8 blocker A803467. Moreover, coimmunoprecipitation experiments from rat DRG lysates indicate the endogenous sodium channel β4 subunits associate with Nav1.8 in DRG neurons. These results suggest that slow TTX-R resurgent currents in DRG neurons are mediated by Nav1.8 and are generated by the same mechanism underlying TTX-S resurgent currents. We also show that both TTX-S and TTX-R resurgent currents in DRG neurons are enhanced by inflammatory mediators. Furthermore, the β4 peptide increased excitability of small DRG neurons in the presence of TTX. We propose that these slow TTX-R resurgent currents contribute to the membrane excitability of nociceptive DRG neurons under normal conditions and that enhancement of both types of resurgent currents by inflammatory mediators could contribute to sensory neuronal hyperexcitability associated with inflammatory pain. PMID:24849353

  9. 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

  10. Loss of sensory input causes rapid structural changes of inhibitory neurons in adult mouse visual cortex.

    PubMed

    Keck, Tara; Scheuss, Volker; Jacobsen, R Irene; Wierenga, Corette J; Eysel, Ulf T; Bonhoeffer, Tobias; Hübener, Mark

    2011-09-01

    A fundamental property of neuronal circuits is the ability to adapt to altered sensory inputs. It is well established that the functional synaptic changes underlying this adaptation are reflected by structural modifications in excitatory neurons. In contrast, the degree to which structural plasticity in inhibitory neurons accompanies functional changes is less clear. Here, we use two-photon imaging to monitor the fine structure of inhibitory neurons in mouse visual cortex after deprivation induced by retinal lesions. We find that a subset of inhibitory neurons carry dendritic spines, which form glutamatergic synapses. Removal of visual input correlates with a rapid and lasting reduction in the number of inhibitory cell spines. Similar to the effects seen for dendritic spines, the number of inhibitory neuron boutons dropped sharply after retinal lesions. Together, these data suggest that structural changes in inhibitory neurons may precede structural changes in excitatory circuitry, which ultimately result in functional adaptation following sensory deprivation.

  11. Agrin-signalling is necessary for the integration of newly generated neurons in the adult olfactory bulb

    PubMed Central

    Burk, Katja; Desoeuvre, Angelique; Boutin, Camille; Smith, Martin A.; Kröger, Stephan; Bosio, Andreas; Tiveron, Marie-Catherine; Cremer, Harold

    2012-01-01

    In the adult forebrain new interneurons are continuously generated and integrated into the existing circuitry of the olfactory bulb. In an attempt to identify signals that regulate this synaptic integration process, we found strong expression of agrin in adult generated neuronal precursors that arrive in the olfactory bulb after their generation in the subventricular zone. While the agrin receptor components MuSK and Lrp4 were below detection level in neuron populations that represent synaptic targets for the new interneurons, the alternative receptor α3Na+K+ATPase was strongly expressed in mitral cells. Using a transplantation approach we demonstrate that agrin-deficient interneuron precursors migrate correctly into the OB. However, in contrast to wildtype neurons, which form synapses and survive for prolonged periods, mutant neurons do not mature and are rapidly eliminated. Using in vivo brain electroporation of the olfactory system we show that the transmembrane form of agrin alone is sufficient to mediate integration and demonstrate that excess transmembrane agrin increases the number of dendritic spines. Lastly, we provide in vivo evidence that an interaction between agrin and α3Na+K+ATPase is of functional importance in this system. PMID:22423096

  12. Comparison of icilin- and cold-evoked responses of spinal neurones, and their modulation of mechanical activity, in a model of neuropathic pain.

    PubMed

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

    2008-06-18

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

  13. DRG2 Regulates G2/M Progression via the Cyclin B1-Cdk1 Complex

    PubMed Central

    Jang, Soo Hwa; Kim, Ah-Ram; Park, Neung-Hwa; Park, Jeong Woo; Han, In-Seob

    2016-01-01

    Developmentally regulated GTP-binding protein 2 (DRG2) plays an important role in cell growth. Here we explored the linkage between DRG2 and G2/M phase checkpoint function in cell cycle progression. We observed that knockdown of DRG2 in HeLa cells affected growth in a wound-healing assay, and tumorigenicity in nude mice xenografts. Flow cytometry assays and [3H] incorporation assays indicated that G2/M phase arrest was responsible for the decreased proliferation of these cells. Knockdown of DRG2 elicited down-regulation of the major mitotic promoting factor, the cyclin B1/Cdk1 complex, but up-regulation of the cell cycle arresting proteins, Wee1, Myt1, and p21. These findings identify a novel role of DRG2 in G2/M progression. PMID:27669826

  14. DRG2 Regulates G2/M Progression via the Cyclin B1-Cdk1 Complex.

    PubMed

    Jang, Soo Hwa; Kim, Ah-Ram; Park, Neung-Hwa; Park, Jeong Woo; Han, In-Seob

    2016-09-01

    Developmentally regulated GTP-binding protein 2 (DRG2) plays an important role in cell growth. Here we explored the linkage between DRG2 and G2/M phase checkpoint function in cell cycle progression. We observed that knockdown of DRG2 in HeLa cells affected growth in a wound-healing assay, and tumorigenicity in nude mice xenografts. Flow cytometry assays and [(3)H] incorporation assays indicated that G2/M phase arrest was responsible for the decreased proliferation of these cells. Knockdown of DRG2 elicited down-regulation of the major mitotic promoting factor, the cyclin B1/Cdk1 complex, but up-regulation of the cell cycle arresting proteins, Wee1, Myt1, and p21. These findings identify a novel role of DRG2 in G2/M progression. PMID:27669826

  15. Thermally reduced graphene is a permissive material for neurons and astrocytes and de novo neurogenesis in the adult olfactory bulb in vivo.

    PubMed

    Defteralı, Çağla; Verdejo, Raquel; Peponi, Laura; Martín, Eduardo D; Martínez-Murillo, Ricardo; López-Manchado, Miguel Ángel; Vicario-Abejón, Carlos

    2016-03-01

    Graphene and graphene-based nanomaterials (GBNs) are being investigated as potential substrates for the growth of neural stem cells (NSCs), neurons and glia in cell culture models. In contrast, reports testing the effects of graphene directly with adult neural cells in vivo are missing. Here we studied the biocompatibility of thermally reduced graphene (TRG) with neurons and glia, as well as with the generation of new neurons in the adult brain in vivo. TRG injected in the brain together with a retroviral vector expressing GFP to label dividing progenitor cells in the core of the adult olfactory bulb (OB) did not alter de novo neurogenesis, neuronal and astrocyte survival nor did it produce a microglial response. These findings indicate that TRG may be a biocompatible material with neuronal and glial cells in vivo and support its use in studies of brain repair and function. PMID:26751821

  16. 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

  17. The impact of DRG reimbursement on strategic planning.

    PubMed

    Zuckerman, A M

    1984-01-01

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

  18. Expression of background potassium channels in rat DRG is cell-specific and down-regulated in a neuropathic pain model

    PubMed Central

    Pollema-Mays, Sarah L.; Centeno, Maria Virginia; Ashford, Crystle J.; Apkarian, A Vania; Martina, Marco

    2013-01-01

    Neuropathic pain is associated with hyperexcitability of DRG neurons. Despite the importance of leakage potassium channels for neuronal excitability, little is known about their cell-specific expression in DRGs and possible modulation in neuropathic pain. Multiple leakage channels are expressed in DRG neurons, including TASK1, TASK3, TRESK, TRAAK, TWIK1, TREK1 and TREK2 but little is known about their distribution among different cell types. Our immunohistochemical studies show robust TWIK1 expression in large and medium size neurons, without overlap with TRPV1 or IB4 staining. TASK1 and TASK3, on the contrary, are selectively expressed in small cells; TASK1 expression closely overlaps TRPV1-positive cells, while TASK3 is expressed in TRPV1- and IB4-negative cells. We also studied mRNA expression of these channels in L4-L5 DRGs in control conditions and up to 4 weeks after spared nerve injury lesion. We found that TWIK1 expression is much higher than TASK1 and TASK3 and is strongly decreased 1, 2 and 4 weeks after neuropathic injury. TASK3 expression, on the other hand, decreases 1 week after surgery but reverts to baseline by 2 weeks; TASK1 shows no significant change at any time point. These data suggest an involvement of TWIK1 in the maintenance of the pain condition. PMID:23994814

  19. Effects of neuron-specific estrogen receptor (ER) α and ERβ deletion on the acute estrogen negative feedback mechanism in adult female mice.

    PubMed

    Cheong, Rachel Y; Porteous, Robert; Chambon, Pierre; Abrahám, István; Herbison, Allan E

    2014-04-01

    The negative feedback mechanism through which 17β-estradiol (E2) acts to suppress the activity of the GnRH neurons remains unclear. Using inducible and cell-specific genetic mouse models, we examined the estrogen receptor (ER) isoforms expressed by neurons that mediate acute estrogen negative feedback. Adult female mutant mice in which ERα was deleted from all neurons in the neonatal period failed to exhibit estrous cycles or negative feedback. Adult mutant female mice with neonatal neuronal ERβ deletion exhibited normal estrous cycles, but a failure of E2 to suppress LH secretion was seen in ovariectomized mice. Mutant mice with a GnRH neuron-selective deletion of ERβ exhibited normal cycles and negative feedback, suggesting no critical role for ERβ in GnRH neurons in acute negative feedback. To examine the adult roles of neurons expressing ERα, an inducible tamoxifen-based Cre-LoxP approach was used to ablate ERα from neurons that express calmodulin kinase IIα in adults. This resulted in mice with no estrous cycles, a normal increase in LH after ovariectomy, but an inability of E2 to suppress LH secretion. Finally, acute administration of ERα- and ERβ-selective agonists to adult ovariectomized wild-type mice revealed that activation of ERα suppressed LH secretion, whereas ERβ agonists had no effect. This study highlights the differences in adult reproductive phenotypes that result from neonatal vs adult ablation of ERα in the brain. Together, these experiments expand previous global knockout studies by demonstrating that neurons expressing ERα are essential and probably sufficient for the acute estrogen negative feedback mechanism in female mice. PMID:24476134

  20. 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.

  1. 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

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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)...

  7. Mutated CTSF in adult-onset neuronal ceroid lipofuscinosis and FTD

    PubMed Central

    van der Zee, Julie; Mariën, Peter; Crols, Roeland; Van Mossevelde, Sara; Dillen, Lubina; Perrone, Federica; Engelborghs, Sebastiaan; Verhoeven, Jo; D'aes, Tine; Ceuterick-De Groote, Chantal; Sieben, Anne; Versijpt, Jan; Cras, Patrick; Martin, Jean-Jacques

    2016-01-01

    Objective: To investigate the molecular basis of a Belgian family with autosomal recessive adult-onset neuronal ceroid lipofuscinosis (ANCL or Kufs disease [KD]) with pronounced frontal lobe involvement and to expand the findings to a cohort of unrelated Belgian patients with frontotemporal dementia (FTD). Methods: Genetic screening in the ANCL family and FTD cohort (n = 461) was performed using exome sequencing and targeted massive parallel resequencing. Results: We identified a homozygous mutation (p.Ile404Thr) in the Cathepsin F (CTSF) gene cosegregating in the ANCL family. No other mutations were found that could explain the disease in this family. All 4 affected sibs developed motor symptoms and early-onset dementia with prominent frontal features. Two of them evolved to akinetic mutism. Disease presentation showed marked phenotypic variation with the onset ranging from 26 to 50 years. Myoclonic epilepsy in one of the sibs was suggestive for KD type A, while epilepsy was not present in the other sibs who presented with clinical features of KD type B. In a Belgian cohort of unrelated patients with FTD, the same heterozygous p.Arg245His mutation was identified in 2 patients who shared a common haplotype. Conclusions: A homozygous CTSF mutation was identified in a recessive ANCL pedigree. In contrast to the previous associations of CTSF with KD type B, our findings suggest that CTSF genetic testing should also be considered in patients with KD type A as well as in early-onset dementia with prominent frontal lobe and motor symptoms. PMID:27668283

  8. Odd-skipped labels a group of distinct neurons associated with the mushroom body and optic lobe in the adult Drosophila brain.

    PubMed

    Levy, Peter; Larsen, Camilla

    2013-11-01

    Olfactory processing has been intensively studied in Drosophila melanogaster. However, we still know little about the descending neural pathways from the higher order processing centers and how these connect with other neural circuits. Here we describe, in detail, the adult projections patterns that arise from a cluster of 78 neurons, defined by the expression of the Odd-skipped transcription factor. We term these neurons Odd neurons. By using expression of genetically encoded axonal and dendritic markers, we show that a subset of the Odd neurons projects dendrites into the calyx of the mushroom body (MB) and axons into the inferior protocerebrum. We exclude the possibility that the Odd neurons are part of the well-known Kenyon cells whose projections form the MB and conclude that the Odd neurons belong to a previously not described class of extrinsic MB neurons. In addition, three of the Odd neurons project into the lobula plate of the optic lobe, and two of these cells extend axons ipsi- and contralaterally in the brain. Anatomically, these cells do not resemble any previously described lobula plate tangential cells (LPTCs) in Drosophila. We show that the Odd neurons are predominantly cholinergic but also include a small number of γ-aminobutyric acid (GABA)ergic neurons. Finally, we provide evidence that the Odd neurons are a hemilineage, suggesting they are born from a defined set of neuroblasts. Our anatomical analysis hints at the possibility that subgroups of Odd neurons could be involved in olfactory and visual processing.

  9. Expression of COUP-TFII Nuclear Receptor in Restricted GABAergic Neuronal Populations in the Adult Rat Hippocampus

    PubMed Central

    Fuentealba, Pablo; Klausberger, Thomas; Karayannis, Theofanis; Suen, Wai Yee; Huck, Jojanneke; Tomioka, Ryohei; Rockland, Kathleen; Capogna, Marco; Studer, Michèle; Morales, Marisela; Somogyi, Peter

    2015-01-01

    The COUP-TFII nuclear receptor, also known as NR2F2, is expressed in the developing ventral telencephalon and modulates the tangential migration of a set of subpallial neuronal progenitors during forebrain development. Little information is available about its expression patterns in the adult brain. We have identified the cell populations expressing COUP-TFII and the contribution of some of them to network activity in vivo. Expression of COUP-TFII by hippocampal pyramidal and dentate granule cells, as well as neurons in the neocortex, formed a gradient increasing from undetectable in the dorsal to very strong in the ventral sectors. In the dorsal hippocampal CA1 area, COUP-TFII was restricted to GABAergic interneurons and expressed in several, largely nonoverlapping neuronal populations. Immunoreactivity was present in calretinin-, neuronal nitric oxide synthase-, and reelin-expressing cells, as well as in subsets of cholecystokinin- or calbindin-expressing or radiatum-retrohippocampally projecting GABAergic cells, but not in parvalbumin-and/or somatostatin-expressing interneurons. In vivo recording and juxtacellular labeling of COUP-TFII-expressing cells revealed neurogliaform cells, basket cells in stratum radiatum and tachykinin-expressing radiatum dentate innervating interneurons, identified by their axodendritic distributions. They showed cell type-selective phase-locked firing to the theta rhythm but no activation during sharp wave/ripple oscillations. These basket cells in stratum radiatum and neurogliaform cells fired at the peak of theta oscillations detected extracellularly in stratum pyramidale, unlike previously reported ivy cells, which fired at the trough. The characterization of COUP-TFII-expressing neurons suggests that this developmentally important transcription factor plays cell type-specific role(s)in the adult hippocampus. PMID:20130170

  10. Phosphorylation of sodium channel Na(v)1.8 by p38 mitogen-activated protein kinase increases current density in dorsal root ganglion neurons.

    PubMed

    Hudmon, Andy; Choi, Jin-Sung; Tyrrell, Lynda; Black, Joel A; Rush, Anthony M; Waxman, Stephen G; Dib-Hajj, Sulayman D

    2008-03-19

    The sensory neuron-specific sodium channel Na(v)1.8 and p38 mitogen-activated protein kinase are potential therapeutic targets within nociceptive dorsal root ganglion (DRG) neurons in inflammatory, and possibly neuropathic, pain. Na(v)1.8 channels within nociceptive DRG neurons contribute most of the inward current underlying the depolarizing phase of action potentials. Nerve injury and inflammation of peripheral tissues cause p38 activation in DRG neurons, a process that may contribute to nociceptive neuron hyperexcitability, which is associated with pain. However, how substrates of activated p38 contribute to DRG neuron hyperexcitability is currently not well understood. We report here, for the first time, that Na(v)1.8 and p38 are colocalized in DRG neurons, that Na(v)1.8 within DRG neurons is a substrate for p38, and that direct phosphorylation of the Na(v)1.8 channel by p38 regulates its function in these neurons. We show that direct phosphorylation of Na(v)1.8 at two p38 phospho-acceptor serine residues on the L1 loop (S551 and S556) causes an increase in Na(v)1.8 current density that is not accompanied by changes in gating properties of the channel. Our study suggests a mechanism by which activated p38 contributes to inflammatory, and possibly neuropathic, pain through a p38-mediated increase of Na(v)1.8 current density. PMID:18354022

  11. 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

  12. Assessing DRG cost accounting with respect to resource allocation and tariff calculation: the case of Germany.

    PubMed

    Vogl, Matthias

    2012-08-30

    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.

  13. 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

  14. Combined 3DISCO clearing method, retrograde tracer and ultramicroscopy to map corneal neurons in a whole adult mouse trigeminal ganglion.

    PubMed

    Launay, Pierre-Serge; Godefroy, David; Khabou, Hanen; Rostene, William; Sahel, Jose-Alain; Baudouin, Christophe; Melik Parsadaniantz, Stéphane; Reaux-Le Goazigo, Annabelle

    2015-10-01

    Tissue clearing and subsequent imaging of intact transparent tissues have provided an innovative way to analyze anatomical pathways in the nervous system. In this study, we combined a recent 3-dimensional imaging of solvent cleared organ (3DISCO) procedure, light-sheet microscopy, fluorescent retrograde tracer, and Imaris software to 3D map corneal sensory neurons within a whole adult mouse trigeminal ganglion (TG). We first established the optimized steps to easily and rapidly clear a fixed TG. We found that the 3DISCO procedure gave excellent results and took less than 3 h to clear the TG. In a second set of experiments, a retrograde tracer (cholera toxin B Alexa 594-conjugated) was applied to de-epithelialized cornea to retrograde-labeled corneal sensory neurons. Two days later, TGs were cleared by the 3DISCO method and serial imaging was performed using light-sheet ultramicroscopic technology. High-resolution images of labeled neurons can be easily and rapidly obtained from a 3D reconstructed whole mouse TG. We then provided a 3D reconstruction of corneal afferent neurons and analyzed their precise localization in the TG. Thus, we showed that neurons supplying corneal sensory innervation exhibit a highly specific limited dorsomedial localization within the TG. We report that our combined method offers the possibility to perform manual (on 20 μm sections) and automated (on 3D reconstructed TG) counting of labeled cells in a cleared mouse TG. To conclude, we illustrate that the combination of the 3DISCO clearing method with light-sheet microscopy, retrograde tracer, and automatic counting represents a rapid and reliable method to analyze a subpopulation of neurons within the peripheral and central nervous system.

  15. 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

  16. 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

  17. Differential action potentials and firing patterns in injured and uninjured small dorsal root ganglion neurons after nerve injury.

    PubMed

    Zhang, Xu-Feng; Zhu, Chang Z; Thimmapaya, Rama; Choi, Won S; Honore, Prisca; Scott, Victoria E; Kroeger, Paul E; Sullivan, James P; Faltynek, Connie R; Gopalakrishnan, Murali; Shieh, Char-Chang

    2004-05-29

    The profile of tetrodotoxin sensitive (TTX-S) and resistant (TTX-R) Na(+) channels and their contribution to action potentials and firing patterns were studied in isolated small dorsal root ganglion (DRG) neurons after L5/L6 spinal nerve ligation (SNL). Total TTX-R Na(+) currents and Na(v) 1.8 mRNA were reduced in injured L5 DRG neurons 14 days after SNL. In contrast, TTX-R Na(+)currents and Na(v) 1.8 mRNA were upregulated in uninjured L4 DRG neurons after SNL. Voltage-dependent inactivation of TTX-R Na(+) channels in these neurons was shifted to hyperpolarized potentials by 4 mV. Two types of neurons were identified in injured L5 DRG neurons after SNL. Type I neurons (57%) had significantly lower threshold but exhibited normal resting membrane potential (RMP) and action potential amplitude. Type II neurons (43%) had significantly smaller action potential amplitude but retained similar RMP and threshold to those from sham rats. None of the injured neurons could generate repetitive firing. In the presence of TTX, only 26% of injured neurons could generate action potentials that had smaller amplitude, higher threshold, and higher rheobase compared with sham rats. In contrast, action potentials and firing patterns in uninjured L4 DRG neurons after SNL, in the presence or absence of TTX, were not affected. These results suggest that TTX-R Na(+) channels play important roles in regulating action potentials and firing patterns in small DRG neurons and that downregulation in injured neurons and upregulation in uninjured neurons confer differential roles in shaping electrogenesis, and perhaps pain transmission, in these neurons. PMID:15120592

  18. Transient coupling of Ng-CAM expression to NgCAM-dependent calcium signaling during migration of new neurons in the adult songbird brain.

    PubMed

    Goldman, S A; Williams, S; Barami, K; Lemmon, V; Nedergaard, M

    1996-01-01

    The adult avian forebrain continues to generate neurons from subependymal zone (SZ) precursor cells, whose neuronal progeny migrate into the brain upon radial guide fibers. These neurons express the immunoglobulin-family adhesion molecule NgCAM, and their migration in culture is disrupted by anti-NgCAM Fab. Confocal imaging of adult zebra finch SZ loaded with the calcium indicator fluo-3, as well as ratio imaging with the indicator fura-2, revealed that migrating new neurons responded to microgram amounts of NgCAM with reversible increments in cytosolic calcium. The calcium response to NgCAM antigen was developmentally restricted, in that it was only manifested by neurons for roughly the 3- to 4-day period between 6 and 9 DIV, even though NgCAM expression persisted tonically thereafter. The period during which NgCAM elicited a calcium signal corresponded to the postmitotic age at which new, bipolar neurons leave the adult SZ to enter the brain parenchyma in vivo. Accordingly, the calcium response to NgCAM was largely limited to morphologically bipolar cells. Anti-NgCAM IgG also evoked a neuronal calcium signal over the same restricted period that NgCAM protein exerted its effect. These findings suggest a dynamic coupling and uncoupling of calcium-dependent signal transduction pathways to a stably expressed surface adhesion molecule, whose function in a given neuron may therefore evolve with cellular maturation.

  19. 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

  20. 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

  1. 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.

  2. Double-pulse calcium channel current facilitation in adult rat sympathetic neurones.

    PubMed Central

    Ikeda, S R

    1991-01-01

    1. Double-pulse facilitation of Ca2+ channel currents in enzymatically dispersed adult rat superior cervical ganglion neurones was investigated using the whole-cell variant of the patch-clamp technique. Voltage-clamp recordings were performed at room temperature (21-24 degrees C) in solutions designed to isolate Ca2+ channel currents. 2. Ba2+ currents, elicited by a 0 mV test pulse, were increased in amplitude when preceded by a 40 ms pulse to voltages greater than 0 mV. The magnitude of facilitation was dependent on pre-pulse voltage and reached a maximum of 50% (i.e. 1.5 x the current amplitude elicited without a pre-pulse) at a pre-pulse voltage of +80 mV. Half-maximal facilitation occurred at about +25 mV. A small decrease (-6%) in test pulse amplitude was present at pre-pulse voltages between -40 and 0 mV. The magnitude of facilitation was also dependent on test pulse voltage. Facilitation was greatest between test pulse voltages of -10 and 0 mV. 3. Facilitation slowly decreased during prolonged (1 h) dialysis of the neurone even though the Ba2+ current amplitude was well maintained. 4. Increasing the pre-pulse duration over the range 0-120 ms produced an exponential increase in facilitation with a time constant of 17.3 ms. Conversely, lengthening the interpulse duration over the range 5-915 ms, while maintaining a constant pre-pulse amplitude and duration, resulted in an exponential decrease in facilitation with a time constant of 197 ms. 5. At a test potential of 0 mV, the decay of the facilitated Ba2+ current component was fitted to a double exponential function with time constants of about 25 and 150 ms. The time constants had little pre-pulse voltage dependence between +30 to +80 mV. 6. The initial rising phase of both the control and facilitated Ba2+ current were reasonably well described by a single exponential (tau rise) after a delay of 300 microseconds. The tau rise versus test pulse potential relationship was 'bell shaped' over the test pulse

  3. Compensation of depleted neuronal subsets by new neurons in a local area of the adult olfactory bulb.

    PubMed

    Murata, Koshi; Imai, Maki; Nakanishi, Shigetada; Watanabe, Dai; Pastan, Ira; Kobayashi, Kazuto; Nihira, Tomoko; Mochizuki, Hideki; Yamada, Shuichi; Mori, Kensaku; Yamaguchi, Masahiro

    2011-07-20

    In the olfactory bulb (OB), loss of preexisting granule cells (GCs) and incorporation of adult-born new GCs continues throughout life. GCs consist of distinct subsets. Here, we examined whether the loss and incorporation of GC subsets are coordinated in the OB. We classified GCs into mGluR2-expressing and -negative subsets and selectively ablated mGluR2-expressing GCs in a local area of the OB with immunotoxin-mediated cell ablation method. The density of mGluR2-expressing GCs showed considerable recovery within several weeks after the ablation. During recovery, an mGluR2-expressing new GC subset was preferentially incorporated over an mGluR2-negative new GC subset in the area of ablation, whereas the preferential incorporation was not observed in the intact area. The area-specific preferential incorporation of mGluR2-expressing new GCs occurred for BrdU analog- and retrovirus-labeled adult-born cells as well as for neonate-derived transplanted cells. The mGluR2-expressing new GCs in the ablated area were synaptically incorporated into the local bulbar circuit. The spine size of mGluR2-expressing new GCs in the ablated area was larger than that of those in the intact area. In contrast, mGluR2-negative new GCs did not show ablated area-specific spine enlargement. These results indicate that local OB areas have a mechanism to coordinate the loss and incorporation of GC subsets by compensatory incorporation of new GC subsets, which involves subset-specific cellular incorporation and subset-specific regulation of spine size.

  4. 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.

  5. Postnatal maternal separation enhances tonic GABA current of cortical layer 5 pyramidal neurons in juvenile rats and promotes genesis of GABAergic neurons in neocortical molecular layer and subventricular zone in adult rats.

    PubMed

    Feng, Mei; Sheng, Guoxia; Li, Zhongxia; Wang, Jiangping; Ren, Keming; Jin, Xiaoming; Jiang, Kewen

    2014-03-01

    Postnatal maternal separation (PMS) has been shown to be associated with an increased vulnerability to psychiatric illnesses in adulthood. However, the underlying neurological mechanisms are not well understood. Here we evaluated its effects on neurogenesis and tonic GABA currents of cortical layer 5 (L5) pyramidal neurons. PMS not only increased cell proliferation in the subventricular zone, cortical layer 1 and hippocampal dentate gyrus in the adult brain, but also promoted the newly generated cells to differentiate into GABAergic neurons, and PMS adult brain maintained higher ratios of GABAergic neurons in the survival of newly generated cells within 5 days immediately post PMS. Additionally, PMS increased the tonic currents at P7-10 and P30-35 in cortical L5 pyramidal cells. Our results suggest that the newly generated GABAergic neurons and the low GABA concentration-activated tonic currents may be involved in the development of psychiatric disorders after PMS.

  6. 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

  7. Fixative composition alters distributions of immunoreactivity for glutaminase and two markers of nociceptive neurons, Nav1.8 and TRPV1, in the rat dorsal root ganglion.

    PubMed

    Hoffman, E Matthew; Schechter, Ruben; Miller, Kenneth E

    2010-04-01

    Most, if not all, dorsal root ganglion (DRG) neurons use the neurotransmitter glutamate. There are, however, conflicting reports of the percentages of DRG neurons that express glutaminase (GLS), the enzyme that synthesizes glutamate, ranging from 30% to 100% of DRG neurons. Defining DRG neuron populations by the expression of proteins like GLS, which indicates function, is routinely accomplished with immunolabeling techniques. Proper characterization of DRG neuron populations relies on accurate detection of such antigens. It is known intuitively that fixation can alter immunoreactivity (IR). In this study, we compared the effects of five formaldehyde concentrations between 0.25% and 4.0% (w/v) and five picric acid concentrations between 0.0% and 0.8% (w/v) on the IR of GLS, the voltage-gated sodium channel 1.8 (Na(v)1.8), and the capsaicin receptor TRPV1. We also compared the effects of five incubation time lengths from 2 to 192 hr, in primary antiserum on IR. Lowering formaldehyde concentration elevated IR for all three antigens, while raising picric acid concentration increased Na(v)1.8 and TRPV1 IR. Increasing IR improved detection sensitivity, which led to higher percentages of labeled DRG neurons. By selecting fixation conditions that optimized IR, we found that all DRG neurons express GLS, 69% of neurons express Na(v)1.8, and 77% of neurons express TRPV1, indicating that some previous studies may have underestimated the percentages of DRG neurons expressing these proteins. This manuscript contains online supplemental material at http://www.jhc.org. Please visit this article online to view these materials. PMID:20026672

  8. Innexins in the lobster stomatogastric nervous system: cloning, phylogenetic analysis, developmental changes and expression within adult identified dye and electrically coupled neurons.

    PubMed

    Ducret, E; Alexopoulos, H; Le Feuvre, Y; Davies, J A; Meyrand, P; Bacon, J P; Fénelon, V S

    2006-12-01

    Gap junctions play a key role in the operation of neuronal networks by enabling direct electrical and metabolic communication between neurons. Suitable models to investigate their role in network operation and plasticity are invertebrate motor networks, which are built of comparatively few identified neurons, and can be examined throughout development; an excellent example is the lobster stomatogastric nervous system. In invertebrates, gap junctions are formed by proteins that belong to the innexin family. Here, we report the first molecular characterization of two crustacean innexins: the lobster Homarus gammarus innexin 1 (Hg-inx1) and 2 (Hg-inx2). Phylogenetic analysis reveals that innexin gene duplication occurred within the arthropod clade before the separation of insect and crustacean lineages. Using in situ hybridization, we find that each innexin is expressed within the adult and developing lobster stomatogastric nervous system and undergoes a marked down-regulation throughout development within the stomatogastric ganglion (STG). The number of innexin expressing neurons is significantly higher in the embryo than in the adult. By combining in situ hybridization, dye and electrical coupling experiments on identified neurons, we demonstrate that adult neurons that express at least one innexin are dye and electrically coupled with at least one other STG neuron. Finally, two STG neurons display no detectable amount of either innexin mRNAs but may express weak electrical coupling with other STG neurons, suggesting the existence of other forms of innexins. Altogether, we provide evidence that innexins are expressed within small neuronal networks built of dye and electrically coupled neurons and may be developmentally regulated. PMID:17156373

  9. PPARα mediates acute effects of palmitoylethanolamide on sensory neurons

    PubMed Central

    Khasabova, Iryna A.; Xiong, Yee; Coicou, Lia G.; Piomelli, Daniele; Seybold, Virginia

    2012-01-01

    The amplitude of the depolarization-evoked Ca2+ transient is larger in dorsal root ganglion (DRG) neurons from tumor-bearing mice compared to that of neurons from naive mice, and the change is mimicked by co-culturing DRG neurons with the fibrosarcoma cells used to generate the tumors (Khasabova et al., 2007). The effect of palmitoylethanolamide (PEA), a ligand for the peroxisome proliferator-activated receptor-alpha (PPARα), was determined on the evoked-Ca2+ transient in the co-culture condition. The level of PEA was reduced in DRG cells from tumor-bearing mice as well as those co-cultured with fibrosarcoma cells. Pretreatment with PEA, a synthetic PPARα agonist (GW7647), or ARN077, an inhibitor of the enzyme that hydrolyses PEA, acutely decreased the amplitude of the evoked Ca2+ transient in small DRG neurons co-cultured with fibrosarcoma cells. The PPARα antagonist GW6471 blocked the effect of each. In contrast, the PPARα agonist was without effect in the control condition, but the antagonist increased the amplitude of the Ca2+ transient suggesting that PPARα receptors are saturated by endogenous ligand under basal conditions. Effects of drugs on mechanical sensitivity in vivo paralleled their effects on DRG neurons in vitro. Local injection of ARN077 decreased mechanical hyperalgesia in tumor-bearing mice, and the effect was blocked by GW6471. These data support the conclusion that the activity of DRG neurons is rapidly modulated by PEA through a PPARα-dependent mechanism. Moreover, agents that increase the activity of PPARα may provide a therapeutic strategy to reduce tumor-evoked pain. PMID:22972997

  10. Mineralocorticoid receptor blocker eplerenone reduces pain behaviors in vivo and decreases excitability in small diameter sensory neurons from local inflamed dorsal root ganglia in vitro

    PubMed Central

    Dong, Fei; Xie, Wenrui; Strong, Judith A.; Zhang, Jun-Ming

    2012-01-01

    Background Inflammation of the dorsal root ganglia (DRG) may contribute to low back pain, postherpetic neuralgia, and neuropathic pain. The mineralocorticoid receptor (MR) plays a pro-inflammatory role in many non-renal tissues, but its role in peripheral pain at the DRG level is not well studied. Methods Local inflammation of the L5 DRG with the immune activator zymosan rapidly leads to mechanical hypersensitivity and increased excitability of sensory neurons. Using this pain model, we applied the MR antagonist eplerenone locally to the inflamed DRG. Excitability of small diameter sensory neurons was examined in acute primary culture, using patch clamp techniques. Results Local eplerenone significantly reduced the mechanical hypersensitivity and shortened its duration. The same dose was ineffective systemically. Immunohistochemical studies showed the MR was present in most neurons, and rapidly translocated to the nucleus 1 day after local DRG inflammation. Activation of satellite glia (defined by expression of glial fibrillary acidic protein) in the inflamed DRG was also reduced by local eplerenone. Increased excitability of small diameter sensory neurons 1 day after inflammation could be observed in vitro. Eplerenone applied in vitro (8 – 12 hours) could reverse this increased excitability. Eplerenone had no effect in neurons isolated from normal, uninflamed DRG. The MR agonist aldosterone (10 nM) applied in vitro increased excitability of neurons isolated from normal DRG. Conclusions The MR may have a pro-nociceptive role in the DRG. Some of its effects may be mediated by neuronal MR. The MR may represent a novel therapeutic target in some pain syndromes. PMID:23023156

  11. Caffeine and modafinil promote adult neuronal cell proliferation during 48 h of total sleep deprivation in rat dentate gyrus.

    PubMed

    Sahu, Surajit; Kauser, Hina; Ray, Koushik; Kishore, Krishna; Kumar, Sanjeev; Panjwani, Usha

    2013-10-01

    It has been established that sleep deprivation (SD) reduces the proliferation of neuronal precursors in the adult hippocampus. It has also been reported that psychostimulant drugs modulate adult neurogenesis. We examined the modulatory role of two psychostimulant drugs modafinil and caffeine on adult neuronal cell proliferation (NCP) during 48 h of total SD. A novel automated cage shaking stimulus was used to induce SD based on animal activity. 5-Bromo-2″-deoxyuridine (BrdU; 50mg/kg/day i.p.) was injected at the onset of the light phase for two days. Rats were successfully sleep deprived for 85-94% of total time. Stereological analysis showed that both caffeine and modafinil treatments during SD improved the number of BrdU positive cells as compared to the SD group. Caffeine treatment during SD, significantly increased early proliferative and post-mitotic stages of doublecortin (DCX) positive cells while modafinil treatment during SD, increased intermediate and post-mitotic stages of DCX positive cells compared to SD+Vehicle group. Brain-Derived Neurotrophic Factor (BDNF) expression on BrdU positive cells as well as in the dentate gyrus (DG) region was decreased significantly after sleep deprivation. Both caffeine and modafinil significantly improved BDNF expression in the DG region. Modafinil, but not caffeine, significantly decreased hippocampal adenosine level during SD in comparison to the SD+Vehicle group. It may be concluded that caffeine or modafinil treatment during 48 h of SD prevents the SD induced decline in neuronal proliferation and differentiation. Caffeine and modafinil induced alterations of NCP during SD may involve modulation of BDNF and adenosine levels.

  12. Astaxanthin rescues neuron loss and attenuates oxidative stress induced by amygdala kindling in adult rat hippocampus.

    PubMed

    Lu, Yan; Xie, Tao; He, Xue-Xin; Mao, Zhuo-Feng; Jia, Li-Jing; Wang, Wei-Ping; Zhen, Jun-Li; Liu, Liang-Min

    2015-06-15

    Oxidative stress plays an important role in the neuronal damage induced by epilepsy. The present study assessed the possible neuroprotective effects of astaxanthin (ATX) on neuronal damage, in hippocampal CA3 neurons following amygdala kindling. Male Sprague-Dawley rats were chronically kindled in the amygdala and ATX or equal volume of vehicle was given by intraperitoneally. Twenty-four hours after the last stimulation, the rats were sacrificed by decapitation. Histopathological changes and the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and reduced glutathione (GSH) were measured, cytosolic cytochrome c (CytC) and caspase-3 activities in the hippocampus were also recorded. We found extensive neuronal damage in the CA3 region in the kindling group, which was preceded by increases of ROS level and MDA concentration and was followed by caspase-3 activation and an increase in cytosolic CytC. Treatment with ATX markedly attenuated the neuronal damage. In addition, ATX significantly decreased ROS and MDA concentrations and increased GSH levels. Moreover, ATX suppressed the translation of CytC release and caspase-3 activation in hippocampus. Together, these results suggest that ATX protects against neuronal loss due to epilepsy in the rat hippocampus by attenuating oxidative damage, lipid peroxidation and inhibiting the mitochondrion-related apoptotic pathway.

  13. 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

  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. PGE2 released by primary sensory neurons modulates Toll-like receptor 4 activities through an EP4 receptor-dependent process.

    PubMed

    Tse, Kai-Hei; Chow, Kevin B S; Wise, Helen

    2016-04-15

    Exogenous prostaglandin E2 (PGE2) displays mixed regulatory properties with regard to inflammatory gene expression in dorsal root ganglion (DRG) cells. We show here that endogenously-produced nanomolar concentrations of PGE2, such as that generated in response to Toll-like receptor 4 (TLR4) stimulation, inhibits both cyclooxygenase-2 (COX-2) and tumour necrosis factor alpha (TNFα) mRNA expression in DRG cells in an EP4 receptor-dependent manner. DRG neurons appear to be the major source of PGE2 in the DRG and likely serve as both an autocrine and paracrine system for limiting over-activation of both DRG neurons and glial cells in response to TLR4 stimulation. PMID:27049555

  16. Lead decreases cell survival, proliferation, and neuronal differentiation of primary cultured adult neural precursor cells through activation of the JNK and p38 MAP kinases.

    PubMed

    Engstrom, Anna; Wang, Hao; Xia, Zhengui

    2015-08-01

    Adult hippocampal neurogenesis is the process whereby adult neural precursor cells (aNPCs) in the subgranular zone (SGZ) of the dentate gyrus (DG) generate adult-born, functional neurons in the hippocampus. This process is modulated by various extracellular and intracellular stimuli, and the adult-born neurons have been implicated in hippocampus-dependent learning and memory. However, studies on how neurotoxic agents affect this process and the underlying mechanisms are limited. The goal of this study was to determine whether lead, a heavy metal, directly impairs critical processes in adult neurogenesis and to characterize the underlying signaling pathways using primary cultured SGZ-aNPCs isolated from adult mice. We report here that lead significantly increases apoptosis and inhibits proliferation in SGZ-aNPCs. In addition, lead significantly impairs spontaneous neuronal differentiation and maturation. Furthermore, we found that activation of the c-Jun NH2-terminal kinase (JNK) and p38 mitogen activated protein (MAP) kinase signaling pathways are important for lead cytotoxicity. Our data suggest that lead can directly act on adult neural stem cells and impair critical processes in adult hippocampal neurogenesis, which may contribute to its neurotoxicity and adverse effects on cognition in adults.

  17. 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.

  18. Adult-onset autosomal recessive ataxia associated with neuronal ceroid lipofuscinosis type 5 gene (CLN5) mutations.

    PubMed

    Mancini, Cecilia; Nassani, Stefano; Guo, Yiran; Chen, Yulan; Giorgio, Elisa; Brussino, Alessandro; Di Gregorio, Eleonora; Cavalieri, Simona; Lo Buono, Nicola; Funaro, Ada; Pizio, Nicola Renato; Nmezi, Bruce; Kyttala, Aija; Santorelli, Filippo Maria; Padiath, Quasar Salem; Hakonarson, Hakon; Zhang, Hao; Brusco, Alfredo

    2015-01-01

    Autosomal recessive inherited ataxias are a growing group of genetic disorders. We report two Italian siblings presenting in their mid-50s with difficulty in walking, dysarthria and progressive cognitive decline. Visual loss, ascribed to glaucoma, manifested a few years before the other symptoms. Brain MRI showed severe cerebellar atrophy, prevalent in the vermis, with marked cortical atrophy of both hemispheres. Exome sequencing identified a novel homozygous mutation (c.935G > A;p.Ser312Asn) in the ceroid neuronal lipofuscinosis type 5 gene (CLN5). Bioinformatics predictions and in vitro studies showed that the mutation was deleterious and likely affects ER-lysosome protein trafficking. Our findings support CLN5 hypomorphic mutations cause autosomal recessive cerebellar ataxia, confirming other reports showing CLN mutations are associated with adult-onset neurodegenerative disorders. We suggest CLN genes should be considered in the molecular analyses of patients presenting with adult-onset autosomal recessive cerebellar ataxia.

  19. Distinct repriming and closed-state inactivation kinetics of Nav1.6 and Nav1.7 sodium channels in mouse spinal sensory neurons.

    PubMed

    Herzog, Raimund I; Cummins, Theodore R; Ghassemi, Farshid; Dib-Hajj, Sulayman D; Waxman, Stephen G

    2003-09-15

    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 (approximately 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

  20. 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

  1. Differential regulation of proliferation and neuronal differentiation in adult rat spinal cord neural stem/progenitors by ERK1/2, Akt, and PLCγ

    PubMed Central

    Chan, Wai Si; Sideris, Alexandra; Sutachan, Jhon J.; Montoya G, Jose V.; Blanck, Thomas J. J.; Recio-Pinto, Esperanza

    2013-01-01

    Proliferation of endogenous neural stem/progenitor cells (NSPCs) has been identified in both normal and injured adult mammalian spinal cord. Yet the signaling mechanisms underlying the regulation of adult spinal cord NSPCs proliferation and commitment toward a neuronal lineage remain undefined. In this study, the role of three growth factor-mediated signaling pathways in proliferation and neuronal differentiation was examined. Adult spinal cord NSPCs were enriched in the presence of fibroblast growth factor 2 (FGF2). We observed an increase in the number of cells expressing the microtubule-associated protein 2 (MAP2) over time, indicating neuronal differentiation in the culture. Inhibition of the mitogen-activated protein kinase or extracellular signal-regulated kinase (ERK) kinase 1 and 2/ERK 1 and 2 (MEK/ERK1/2) or the phosphoinositide 3-kinase (PI3K)/Akt pathways suppressed active proliferation in adult spinal cord NSPC cultures; whereas neuronal differentiation was negatively affected only when the ERK1/2 pathway was inhibited. Inhibition of the phospholipase Cγ (PLCγ) pathway did not affect proliferation or neuronal differentiation. Finally, we demonstrated that the blockade of either the ERK1/2 or PLCγ signaling pathways reduced neurite branching of MAP2+ cells derived from the NSPC cultures. Many of the MAP2+ cells expressed synaptophysin and had a glutamatergic phenotype, indicating that over time adult spinal cord NSPCs had differentiated into mostly glutamatergic neurons. Our work provides new information regarding the contribution of these pathways to the proliferation and neuronal differentiation of NSPCs derived from adult spinal cord cultures, and emphasizes that the contribution of these pathways is dependent on the origin of the NSPCs. PMID:23986655

  2. 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

  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. 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

  5. Matrix metalloproteinases in the adult brain physiology: a link between c-Fos, AP-1 and remodeling of neuronal connections?

    PubMed

    Kaczmarek, Leszek; Lapinska-Dzwonek, Joanna; Szymczak, Sylwia

    2002-12-16

    Matrix metalloproteinases (MMPs), together with their endogenous inhibitors (TIMPs) form an enzymatic system that plays an important role in a variety of physiological and pathological conditions. These proteins are also expressed in the brain, especially under pathological conditions, in which glia as well as invading inflammatory cells provide the major source of the MMP activity. Surprisingly little is known about the MMP function(s) in adult neuronal physiology. This review describes available data on this topic, which is presented in a context of knowledge about the MMP/TIMP system in other organs as well as in brain disorders. An analysis of the MMP and TIMP expression patterns in the brain, along with a consideration of their regulatory mechanisms and substrates, leads to the proposal of possible roles of the MMP system in the brain. This analysis suggests that MMPs may play an important role in the neuronal physiology, especially in neuronal plasticity, including their direct participation in the remodeling of synaptic connections-a mechanism pivotal for learning and memory.

  6. “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

  7. Cyclooxygenase-1 is a marker for a subpopulation of putative nociceptive neurons in rat dorsal root ganglia.

    PubMed

    Chopra, B; Giblett, S; Little, J G; Donaldson, L F; Tate, S; Evans, R J; Grubb, B D

    2000-03-01

    Immunocytochemical and morphometric techniques were used to quantify the distribution of cyclooxygenase (cox)-containing neurons in rat L5 dorsal root ganglia (DRG). Cox-1 immunolabelling was almost exclusively restricted to small diameter DRG neurons (< 1000 microm2), and was extensively colocalized with calcitonin gene-related peptide (CGRP) and isolectin B4 (IB4). Cox-1 was present in 65% and 70% of CGRP- and IB4-labelled neurons, respectively. Cox-1 labelling was also found in neurons expressing the sensory neuron-specific (SNS) Na+ channel. Cox-2 labelling was absent in DRG from normal rats. In the Freund's adjuvant model of monoarthritis, the proportion of cox-1-positive DRG neurons was unchanged and no neurons were found to be labelled for cox-2. In primary tissue culture, cox-1 immunolabelling persisted in vitro for up to 9 days and was present in morphologically identical neurons. The selective expression of cox-1 in peripheral ganglia was confirmed by the small number of nodose ganglion neurons and superior cervical ganglion (SCG) neurons labelled for cox-1. These data suggest that cox-1 is a marker for a subpopulation of putative nociceptive neurons in vitro and in vivo, and suggests that the prostaglandins synthesized by these neurons may be important for nociceptor function. These data may have important implications for the mode and mechanism of action of non-steroidal anti-inflammatory drugs (NSAIDs). PMID:10762321

  8. 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

  9. Plastic and stable electrophysiological properties of adult avian forebrain song-control neurons across changing breeding conditions.

    PubMed

    Meitzen, John; Weaver, Adam L; Brenowitz, Eliot A; Perkel, David J

    2009-05-20

    Steroid sex hormones drive changes in the nervous system and behavior in many animal taxa, but integrating the former with the latter remains challenging. One useful model system for meeting this challenge is seasonally breeding songbirds. In these species, plasma testosterone levels rise and fall across the seasons, altering song behavior and causing dramatic growth and regression of the song-control system, a discrete set of nuclei that control song behavior. Whereas the cellular mechanisms underlying changes in nucleus volume have been studied as a model for neural growth and degeneration, it is unknown whether these changes in neural structure are accompanied by changes in electrophysiological properties other than spontaneous firing rate. Here we test the hypothesis that passive and active neuronal properties in the forebrain song-control nuclei HVC and RA change across breeding conditions. We exposed adult male Gambel's white-crowned sparrows to either short-day photoperiod or long-day photoperiod and systemic testosterone to simulate nonbreeding and breeding conditions, respectively. We made whole-cell recordings from RA and HVC neurons in acute brain slices. We found that RA projection neuron membrane time constant, capacitance, and evoked and spontaneous firing rates were all increased in the breeding condition; the measured electrophysiological properties of HVC interneurons and projection neurons were stable across breeding conditions. This combination of plastic and stable intrinsic properties could directly impact the song-control system's motor control across seasons, underlying changes in song stereotypy. These results provide a valuable framework for integrating how steroid hormones modulate cellular physiology to change behavior.

  10. Plastic and stable electrophysiological properties of adult avian forebrain song-control neurons across changing breeding conditions.

    PubMed

    Meitzen, John; Weaver, Adam L; Brenowitz, Eliot A; Perkel, David J

    2009-05-20

    Steroid sex hormones drive changes in the nervous system and behavior in many animal taxa, but integrating the former with the latter remains challenging. One useful model system for meeting this challenge is seasonally breeding songbirds. In these species, plasma testosterone levels rise and fall across the seasons, altering song behavior and causing dramatic growth and regression of the song-control system, a discrete set of nuclei that control song behavior. Whereas the cellular mechanisms underlying changes in nucleus volume have been studied as a model for neural growth and degeneration, it is unknown whether these changes in neural structure are accompanied by changes in electrophysiological properties other than spontaneous firing rate. Here we test the hypothesis that passive and active neuronal properties in the forebrain song-control nuclei HVC and RA change across breeding conditions. We exposed adult male Gambel's white-crowned sparrows to either short-day photoperiod or long-day photoperiod and systemic testosterone to simulate nonbreeding and breeding conditions, respectively. We made whole-cell recordings from RA and HVC neurons in acute brain slices. We found that RA projection neuron membrane time constant, capacitance, and evoked and spontaneous firing rates were all increased in the breeding condition; the measured electrophysiological properties of HVC interneurons and projection neurons were stable across breeding conditions. This combination of plastic and stable intrinsic properties could directly impact the song-control system's motor control across seasons, underlying changes in song stereotypy. These results provide a valuable framework for integrating how steroid hormones modulate cellular physiology to change behavior. PMID:19458226

  11. Environmental enrichment enhances episodic-like memory in association with a modified neuronal activation profile in adult mice.

    PubMed

    Leger, Marianne; Quiedeville, Anne; Paizanis, Eleni; Natkunarajah, Sharuja; Freret, Thomas; Boulouard, Michel; Schumann-Bard, Pascale

    2012-01-01

    Although environmental enrichment is well known to improve learning and memory in rodents, the underlying neuronal networks' plasticity remains poorly described. Modifications of the brain activation pattern by enriched condition (EC), especially in the frontal cortex and the baso-lateral amygdala, have been reported during an aversive memory task in rodents. The aims of our study were to examine 1) whether EC modulates episodic-like memory in an object recognition task and 2) whether EC modulates the task-induced neuronal networks. To this end, adult male mice were housed either in standard condition (SC) or in EC for three weeks before behavioral experiments (n = 12/group). Memory performances were examined in an object recognition task performed in a Y-maze with a 2-hour or 24-hour delay between presentation and test (inter-session intervals, ISI). To characterize the mechanisms underlying the promnesiant effect of EC, the brain activation profile was assessed after either the presentation or the test sessions using immunohistochemical techniques with c-Fos as a neuronal activation marker. EC did not modulate memory performances after a 2 h-ISI, but extended object recognition memory to a 24 h-ISI. In contrast, SC mice did not discriminate the novel object at this ISI. Compared to SC mice, no activation related to the presentation session was found in selected brain regions of EC mice (in particular, no effect was found in the hippocampus and the perirhinal cortex and a reduced activation was found in the baso-lateral amygdala). On the other hand, an activation of the hippocampus and the infralimbic cortex was observed after the test session for EC, but not SC mice. These results suggest that the persistence of object recognition memory in EC could be related to a reorganization of neuronal networks occurring as early as the memory encoding.

  12. Characterization of neurons from adult human skin-derived precursors in serum-free medium : a PCR array and immunocytological analysis.

    PubMed

    Lebonvallet, Nicolas; Boulais, Nicholas; Le Gall, Christelle; Chéret, Jeremy; Pereira, Ulysse; Mignen, Olivier; Bardey, Vincent; Jeanmaire, Christine; Danoux, Louis; Pauly, Gilles; Misery, Laurent

    2012-03-01

    Adult stem cells could be small sources of neurons or other cellular types for regenerative medicine and tissue engineering. Recently, pluripotent stem cells have been extracted from skin tissue, which opened a new accessible source for research. To routinely obtain a high yield of functional neurons from adult human skin stem cells with defined serum-free medium, stem cells from abdominal skin were cultured in serum-free medium. To differentiate them, we used a defined medium containing growth factors. Differentiated cells were identified using the following methods: (i) Oil-red-O staining for adipocytes, immunocytochemistry with antibodies recognising (ii) neurofilaments and PGP9.5 for neural differentiation, (iii) glial fibrillary acidic protein (GFAP) for glial differentiation, (iv) Ki-67 for proliferative cells, (v) FM1-43 staining to analyse vesicle trafficking in neuronal cells and (vi) a PCR array was used. Stem cells were floating in spheres and were maintained in culture for 4 months or more. They expressed nestin and Oct 4 and were proliferative. We induced specific differentiation into adipocytes, glial and neuronal cells. The yields of differentiated neurons were high and reproducible. They were maintained for long time (1 month) in the culture medium. Furthermore, these neurons incorporated FM1-43 dye, which indicates a potent acquisition of synaptic features in neurons. Stem cells from adult human skin could be valuable and reproducible tools/source to obtain high numbers of functional specific cellular types, such as neurons, for tissue engineering. In this work, the possibility to obtain a high yield of differentiated neurons, with the ability of endocytosis and vesicle cell trafficking, was shown.

  13. 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

  14. Spinal Nerve Ligation Decreases γ-Aminobutyric AcidB Receptors on Specific Populations of Immunohistochemically Identified Neurons in L5 Dorsal Root Ganglion of the Rat

    PubMed Central

    Engle, Mitchell P.; Merrill, Michelle A.; De Prado, Blanca Marquez; Hammond, Donna L.

    2014-01-01

    This study examined the distribution of γ-aminobutyric acid (GABA)B receptors on immunohistochemically identified neurons, and levels of GABAB(1) and GABAB(2) mRNA, in the L4 and L5 dorsal root ganglia (DRG) of the rat in the absence of injury and 2 weeks after L5 spinal nerve ligation. In uninjured DRG, GABAB(1) immunoreactivity colocalized exclusively with the neuronal marker (NeuN) and did not colocalize with the satellite cell marker S-100. The GABAB(1) subunit colocalized to >97% of DRG neurons immunoreactive (IR) for neurofilament 200 (N52) or calcitonin gene-related peptide (CGRP), or labeled by isolectin B4 (IB4). Immunoreactivity for GABAB(2) was not detectable. L5 spinal nerve ligation did not alter the number of GABAB(1)-IR neurons or its colocalization pattern in the L4 DRG. However, ligation reduced the number of GABAB(1)-IR neurons in the L5 DRG by ≈38% compared with sham-operated and naïve rats. Specifically, ligation decreased the number of CGRP-IR neurons in the L5 DRG by 75%, but did not decrease the percent colocalization of GABAB(1) in those that remained. In the few IB4-positive neurons that remained in the L5 DRG, colocalization of GABAB(1)-IR decreased to 75%. Ligation also decreased levels of GABAB(1) and GABAB(2) mRNA in the L5, but not the L4 DRG compared with sham-operated or naïve rats. These findings indicate that the GABAB receptor is positioned to presynaptically modulate afferent transmission by myelinated, unmyelinated, and peptidergic afferents in the dorsal horn. Loss of GABAB receptors on primary afferent neurons may contribute to the development of mechanical allodynia after L5 spinal nerve ligation. PMID:22120979

  15. GABA-cAMP response element-binding protein signaling regulates maturation and survival of newly generated neurons in the adult hippocampus.

    PubMed

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

    2009-06-24

    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 signaling pathways. Here, we investigate the role of cAMP response element-binding protein (CREB) signaling in adult hippocampal neurogenesis. CREB is activated in new granule neurons during a distinct developmental period. Loss of CREB function in a cell-autonomous manner impairs dendritic development, decreases the expression of the neurogenic transcription factor NeuroD and of the neuronal microtubule-associated protein, doublecortin (DCX), and compromises the survival of newborn neurons. In addition, GABA-mediated excitation regulates CREB activation at early developmental stages. Importantly, developmental defects after loss of GABA-mediated excitation can be compensated by enhanced CREB signaling. These results indicate that CREB signaling is a central pathway in adult hippocampal neurogenesis, regulating the development and survival of new hippocampal neurons downstream of GABA-mediated excitation.

  16. 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

  17. Adult newborn neurons are involved in learning acquisition and long-term memory formation: the distinct demands on temporal neurogenesis of different cognitive tasks.

    PubMed

    Suárez-Pereira, Irene; Canals, Santiago; Carrión, Angel M

    2015-01-01

    There is evidence that adult hippocampal neurogenesis influences hippocampal function, although the role these neurons fulfill in learning and consolidation processes remains unclear. Using a novel fast X-ray ablation protocol to deplete neurogenic cells, we demonstrate that immature adult hippocampal neurons are required for hippocampal learning and long-term memory formation. Moreover, we found that long-term memory formation in the object recognition and passive avoidance tests, two paradigms that involve circuits with distinct emotional components, had different temporal demands on hippocampal neurogenesis. These results reveal new and unexpected aspects of neurogenesis in cognitive processes.

  18. Tamoxifen-inducible NaV1.8-CreERT2 recombinase activity in nociceptive neurons of dorsal root ganglia.

    PubMed

    Zhao, Jing; Nassar, Mohammed A; Gavazzi, Isabella; Wood, John N

    2006-08-01

    To explore the function of genes expressed in adult mouse nociceptive neurons, we generated heterozygous knock-in mice expressing the tamoxifen-inducible Cre recombinase construct CreERT2 downstream of the Na(V)1.8 promoter. CreERT2 encodes a Cre recombinase (Cre) fused to a mutant estrogen ligand-binding domain (ERT2) that requires the presence of tamoxifen for activity. We have previously shown that heterozygous Na(V)1.8-Cre mice will delete loxP flanked genes specifically in nociceptive sensory neurons from embryonic day 14. We therefore used the same strategy of homologous recombination and mouse generation, substituting the Cre cassette with CreERT2. No functional Cre recombinase activity was found in CreERT2 mice crossed with reporter mice in the absence of tamoxifen. We found that, as with Na(V)1.8-Cre mice, functional Cre recombinase was present in nociceptive sensory neurons after tamoxifen induction in vivo. However, the percentage of dorsal root ganglion (DRG) neurons expressing functional Cre activity was much reduced (<10% of the number found in the Na(V)1.8-Cre mouse). We also examined Cre recombinase activity in sensory neurons in culture. After treatment with 1 muM tamoxifen for 48 h, 15% of DRG neurons showed Cre activity. Na(V)1.8-CreERT2 animals may thus be useful for single cell studies of the functional consequences of gene ablation in culture, but are unlikely to be useful for behavioral studies. PMID:16850455

  19. 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.

  20. 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

  1. Predicting charges for inpatient medical rehabilitation using severity, DRG, age, and function.

    PubMed Central

    McGinnis, G E; Osberg, J S; DeJong, G; Seward, M L; Branch, L G

    1987-01-01

    We examined the effectiveness of using diagnosis related groups (DRGs), Severity of Illness Index (SII), age and function at admission to predict inpatient charges for medical rehabilitation. Data from our sample of 199 indicate that DRGs alone explained approximately 12 per cent of the variation in charges for inpatient rehabilitation while SII explained 26 per cent of the variation. SII, DRG, and age together yielded the highest regression coefficient, accounting for nearly 39 per cent of the variation in total charges; SII and age accounted for 36 per cent of the variation. Within DRG categories, SII was the only important predictor of inpatient charges accounting for 23 per cent of the variation in charges among stroke patients (DRG 014) and 28 per cent of the variation in charges among hip fracture patients (DRG 210). Function at admission was not a useful predictor of inpatient rehabilitation charges within DRGs. These results suggest that SII and age may be useful in developing a DRG-based prospective payment system for inpatient medical rehabilitation. PMID:3109268

  2. 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

  3. TNF-α enhances the currents of voltage gated sodium channels in uninjured dorsal root ganglion neurons following motor nerve injury.

    PubMed

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

    2011-02-01

    The ectopic discharges observed in uninjured dorsal root ganglion (DRG) neurons following various lesions of spinal nerves have been attributed to functional alterations of voltage-gated sodium channels (VGSCs). Such mechanisms may be important for the development of neuropathic pain. However, the pathophysiology underlying the functional modulation of VGSCs following nerve injury is largely unknown. Here, we studied this issue with use of a selective lumbar 5 ventral root transection (L5-VRT) model, in which dorsal root ganglion (DRG) neurons remain intact. We found that the L5-VRT increased the current densities of TTX-sensitive Na channels as well as currents in Nav1.8, but not Nav1.9 channels in uninjured DRG neurons. The thresholds of action potentials decreased and firing rates increased in DRG neurons following L5-VRT. As we found that levels of tumor necrosis factor-alpha (TNF-α) increased in cerebrospinal fluid (CSF) and in DRG tissue after L5-VRT, we tested whether the increased TNF-α might result in the changes in sodium channels. Indeed, recombinant rat TNF (rrTNF) enhanced the current densities of TTX-S and Nav1.8 in cultured DRG neurons dose-dependently. Furthermore, genetic deletion of TNF receptor 1 (TNFR-1) in mice attenuated the mechanical allodynia and prevented the increase in sodium currents in DRG neurons induced by L5-VRT. These data suggest that the increase in sodium currents in uninjured DRG neurons following nerve injury might be mediated by over-production of TNF-α. PMID:21145890

  4. 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

  5. Increased Expression of the Large Conductance, Calcium-Activated K+ (BK) Channel in Adult-Onset Neuronal Ceroid Lipofuscinosis

    PubMed Central

    Donnelier, Julien; Braun, Samuel T.; Dolzhanskaya, Natalia; Ahrendt, Eva; Braun, Andrew P.; Velinov, Milen; Braun, Janice E. A.

    2015-01-01

    Cysteine string protein (CSPα) is a presynaptic J protein co-chaperone that opposes neurodegeneration. Mutations in CSPα (i.e., Leu115 to Arg substitution or deletion (Δ) of Leu116) cause adult neuronal ceroid lipofuscinosis (ANCL), a dominantly inherited neurodegenerative disease. We have previously demonstrated that CSPα limits the expression of large conductance, calcium-activated K+ (BK) channels in neurons, which may impact synaptic excitability and neurotransmission. Here we show by western blot analysis that expression of the pore-forming BKα subunit is elevated ~2.5 fold in the post-mortem cortex of a 36-year-old patient with the Leu116∆ CSPα mutation. Moreover, we find that the increase in BKα subunit level is selective for ANCL and not a general feature of neurodegenerative conditions. While reduced levels of CSPα are found in some postmortem cortex specimens from Alzheimer’s disease patients, we find no concomitant increase in BKα subunit expression in Alzheimer’s specimens. Both CSPα monomer and oligomer expression are reduced in synaptosomes prepared from ANCL cortex compared with control. In a cultured neuronal cell model, CSPα oligomers are short lived. The results of this study indicate that the Leu116∆ mutation leads to elevated BKα subunit levels in human cortex and extend our initial work in rodent models demonstrating the modulation of BKα subunit levels by the same CSPα mutation. While the precise sequence of pathogenic events still remains to be elucidated, our findings suggest that dysregulation of BK channels may contribute to neurodegeneration in ANCL. PMID:25905915

  6. Sporadic adult-onset neuronal intranuclear inclusion disease with the main presentation of repeated cerebellar ataxia: a case study.

    PubMed

    Sakurai, Takeo; Harada, Seiko; Wakida, Kenji; Yoshida, Mari; Nishida, Hiroshi

    2016-06-22

    A 66-year-old woman suddenly experienced unsteadiness while walking; she had experienced the same symptom before, but it had resolved immediately. Her neurological findings showed cerebellar ataxia, absence of tendon reflex in the extremities, and orthostatic hypotension. MRI with DWI of the brain showed linear high-intensity areas at the white matter just below the cerebral cortex. Therefore, we suspected neuronal intranuclear inclusion disease (NIID). In her cutaneous skin biopsy, intranuclear inclusion bodies, which tested positive for an anti-ubiquitin antibody and anti-p62 antibody, were observed in sweat gland cells and fibroblasts; therefore, we diagnosed her with NIID. As no one in her family had similar symptoms, this was a case of sporadic NIID. Adult-onset NIID with the main presentation of cerebellar ataxia is rare; in our case, this repeated acute-onset symptom was a unique manifestation of the condition. PMID:27181748

  7. 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

  8. Neuronal regeneration in the cerebellum of adult teleost fish, Apteronotus leptorhynchus: guidance of migrating young cells by radial glia.

    PubMed

    Clint, S C; Zupanc, G K

    2001-09-23

    In contrast to mammals, adult fish exhibit an enormous potential to replace injured brain neurons by newly generated ones. In the present study, the role of radial glia, identified by immunostaining against fibrillary acidic protein (GFAP), was examined in this process of neuronal regeneration. Approximately 8 days after application of a mechanical lesion to the corpus cerebelli in the teleost fish Apteronotus leptorhynchus, the areal density of radial glial fibers increased markedly in the ipsilateral dorsal molecular layer compared to shorter survival times, or to the densities found in the intact brain or in the hemisphere contralateral to the lesion. This density remained elevated throughout the time period of up to 100 days examined. The increase in fiber density was followed approximately 2 days later by a rise in the areal density of young cells, characterized by labeling with the nuclear dye DAPI, in the ipsilateral dorsal molecular layer. Based on this remarkable spatio-temporal correlation, and the frequently observed close apposition of elongated young cells to radial glial fibers, we hypothesize that radial glia play an important role in the guidance of migrating young cells from their proliferation zones to the site of lesion where regeneration takes place.

  9. Amyloid burden, neuronal function, and cognitive decline in middle-aged adults at risk for Alzheimer's disease.

    PubMed

    Okonkwo, Ozioma C; Oh, Jennifer M; Koscik, Rebecca; Jonaitis, Erin; Cleary, Caitlin A; Dowling, N Maritza; Bendlin, Barbara B; Larue, Asenath; Hermann, Bruce P; Barnhart, Todd E; Murali, Dhanabalan; Rowley, Howard A; Carlsson, Cynthia M; Gallagher, Catherine L; Asthana, Sanjay; Sager, Mark A; Christian, Brad T; Johnson, Sterling C

    2014-04-01

    The relative influence of amyloid burden, neuronal structure and function, and prior cognitive performance on prospective memory decline among asymptomatic late middle-aged individuals at risk for Alzheimer's disease (AD) is currently unknown. We investigated this using longitudinal cognitive data from 122 middle-aged adults (21 "Decliners" and 101 "Stables") enrolled in the Wisconsin Registry for Alzheimer's Prevention who underwent multimodality neuroimaging [11C-Pittsburgh Compound B (PiB), 18F-fluorodeoxyglucose (FDG), and structural/functional magnetic resonance imaging (fMRI)] 5.7 ± 1.4 years (range = 2.9-8.9) after their baseline cognitive assessment. Covariate-adjusted regression analyses revealed that the only imaging measure that significantly distinguished Decliners from Stables (p = .027) was a Neuronal Function composite derived from FDG and fMRI. In contrast, several cognitive measures, especially those that tap episodic memory, significantly distinguished the groups (p's<.05). Complementary receiver operating characteristic curve analyses identified the Brief Visuospatial Memory Test-Revised (BVMT-R) Total (.82 ± .05, p < .001), the BVMT-R Delayed Recall (.73 ± .06, p = .001), and the Reading subtest from the Wide-Range Achievement Test-III (.72 ± .06, p = .002) as the top three measures that best discriminated the groups. These findings suggest that early memory test performance might serve a more clinically pivotal role in forecasting future cognitive course than is currently presumed.

  10. Amyloid burden, neuronal function, and cognitive decline in middle-aged adults at risk for Alzheimer’s disease

    PubMed Central

    Okonkwo, Ozioma C.; Oh, Jennifer M.; Koscik, Rebecca; Jonaitis, Erin; Cleary, Caitlin A.; Dowling, N. Maritza; Bendlin, Barbara B.; LaRue, Asenath; Hermann, Bruce P.; Barnhart, Todd E.; Murali, Dhanabalan; Rowley, Howard A.; Carlsson, Cynthia M.; Gallagher, Catherine L.; Asthana, Sanjay; Sager, Mark A.; Christian, Brad T.; Johnson, Sterling C.

    2014-01-01

    The relative influence of amyloid burden, neuronal structure and function, and prior cognitive performance on prospective memory decline among asymptomatic late middle-aged individuals at risk for Alzheimer’s disease (AD) is currently unknown. We investigated this using longitudinal cognitive data from 122 middle-aged adults (21 “Decliners” and 101 “Stables”) enrolled in the Wisconsin Registry for Alzheimer’s Prevention who underwent multimodality neuroimaging (11C-Pittsburgh Compound B (PiB), 18F-fluorodeoxyglucose (FDG), and structural/functional MRI) 5.7±1.4 years (range=2.9–8.9) after their baseline cognitive assessment. Covariate-adjusted regression analyses revealed that the only imaging measure that significantly distinguished Decliners from Stables (p=.027) was a Neuronal Function composite derived from FDG and fMRI. In contrast, several cognitive measures, especially those that tap episodic memory, significantly distinguished the groups (p’s < .05). Complementary receiver operating characteristic curve analyses identified the Brief Visuospatial Memory Test-Revised (BVMT-R) Total (.82±.05, p<.001), the BVMT-R Delayed Recall (.73±.06, p=.001), and the Reading subtest from the Wide-Range Achievement Test-III (.72±.06, p=.002) as the top three measures that best discriminated the groups. These findings suggest that early memory test performance might serve a more clinically-pivotal role in forecasting future cognitive course than is currently presumed. PMID:24621494

  11. Interferon-gamma but not TNF alpha promotes neuronal differentiation and neurite outgrowth of murine adult neural stem cells.

    PubMed

    Wong, Galaxy; Goldshmit, Yona; Turnley, Ann M

    2004-05-01

    Neural trauma, such as traumatic brain injury or stroke, results in a vigorous inflammatory response at and near the site of injury, with cytokine production by endogenous glial cells and invading immune cells. Little is known of the effect that these cytokines have on neural stem cell function. Here we examine the effects of two inflammatory cytokines, interferon-gamma (IFN gamma) and tumour necrosis factor-alpha (TNFalpha), on adult neural stem cells. Neural stem cells grown in the presence of either cytokine failed to generate neurospheres. Cytotoxicity assays showed that TNF alpha but not IFN gamma was toxic to the neural stem cells under proliferative conditions. Under differentiating conditions, neither cytokine was toxic; however, IFN gamma enhanced neuronal differentiation, rapidly increasing beta III-tubulin positive cell numbers 3-4 fold and inhibiting astrocyte generation. Furthermore, neurite outgrowth and the number of neurites per neuron was enhanced in cells differentiated in the presence of IFN gamma. Therefore, both inflammatory cytokines examined have substantial, but different effects on neural stem cell function and suggests that regulation of the inflammatory environment following brain injury may influence the ability of neural stem cells to repair the damage. PMID:15081598

  12. Dynamic development of the first synapse impinging on adult-born neurons in the olfactory bulb circuit.

    PubMed

    Katagiri, Hiroyuki; Pallotto, Marta; Nissant, Antoine; Murray, Kerren; Sassoè-Pognetto, Marco; Lledo, Pierre-Marie

    2011-02-01

    The olfactory bulb (OB) receives and integrates newborn interneurons throughout life. This process is important for the proper functioning of the OB circuit and consequently, for the sense of smell. Although we know how these new interneurons are produced, the way in which they integrate into the pre-existing ongoing circuits remains poorly documented. Bearing in mind that glutamatergic inputs onto local OB interneurons are crucial for adjusting the level of bulbar inhibition, it is important to characterize when and how these inputs from excitatory synapses develop on newborn OB interneurons. We studied early synaptic events that lead to the formation and maturation of the first glutamatergic synapses on adult-born granule cells (GCs), the most abundant subtype of OB interneuron. Patch-clamp recordings and electron microscopy (EM) analysis were performed on adult-born interneurons shortly after their arrival in the adult OB circuits. We found that both the ratio of N-methyl-D-aspartate receptor (NMDAR) to α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), and the number of functional release sites at proximal inputs reached a maximum during the critical period for the sensory-dependent survival of newborn cells, well before the completion of dendritic arborization. EM analysis showed an accompanying change in postsynaptic density shape during the same period of time. Interestingly, the latter morphological changes disappeared in more mature newly-formed neurons, when the NMDAR to AMPAR ratio had decreased and functional presynaptic terminals expressed only single release sites. Together, these findings show that the first glutamatergic inputs to adult-generated OB interneurons undergo a unique sequence of maturation stages.

  13. The effect of MDMA-induced anxiety on neuronal apoptosis in adult male rats' hippocampus.

    PubMed

    Karimi, S; Jahanshahi, M; Golalipour, M J

    2014-01-01

    Ecstasy or MDMA as a psychoactive drug and hallucinogen is considered one of the most commonly used drugs in the world. This psychotropic substance is discussed both as sexually stimulating and reducing fear and anxiety. Amphetamines also destroy neurons in some brain areas. The aim of this study was to investigate the effects of MDMA on anxiety and apoptosis of hippocampal neurons. Forty-two male Wistar rats of mean weight 200-220 g were used and distributed into six groups [control, control-saline, and experimental groups (1.25, 2.5, 5, 10 mg/kg)]. Rats in experimental groups received MDMA at different doses for seven days by intraperitoneal injection and the control-saline group received saline (1 ml/kg); anxiety was then investigated by plus-maze test. Forty-eight hours after behavioural testing brains were taken from animals and fixed, and after tissue processing, slices were stained with TUNEL kit for apoptotic cells. The area densities of apoptotic neurons were measured throughout the hippocampus and compared in all groups (P < 0.05). Physiological studies showed that 1.25 mg/kg and 2.5 mg/kg doses caused anti-anxiety behaviour and 5 and 10 mg/kg doses of MDMA caused anxietylike behaviour. Moreover, our histological study showed that ecstasy increased apoptotic cell numbers and the highest increase was observed with the 10 mg/kg dose of MDMA. We concluded that MDMA can cause different responses of anxiety-like behaviour in different doses. This phenomenon causes a different ratio of apoptosis in hippocampal formation. Reduction of anxiety-like behaviour induced by the 2.5 mg/kg dose of MDMA can control apoptosis. PMID:25152052

  14. 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

  15. [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

  16. The Drug Diazaborine Blocks Ribosome Biogenesis by Inhibiting the AAA-ATPase Drg1*

    PubMed Central

    Loibl, Mathias; Klein, Isabella; Prattes, Michael; Schmidt, Claudia; Kappel, Lisa; Zisser, Gertrude; Gungl, Anna; Krieger, Elmar; Pertschy, Brigitte; Bergler, Helmut

    2014-01-01

    The drug diazaborine is the only known inhibitor of ribosome biogenesis and specifically blocks large subunit formation in eukaryotic cells. However, the target of this drug and the mechanism of inhibition were unknown. Here we identify the AAA-ATPase Drg1 as a target of diazaborine. Inhibitor binding into the second AAA domain of Drg1 requires ATP loading and results in inhibition of ATP hydrolysis in this site. As a consequence the physiological activity of Drg1, i.e. the release of Rlp24 from pre-60S particles, is blocked, and further progression of cytoplasmic preribosome maturation is prevented. Our results identify the first target of an inhibitor of ribosome biogenesis and provide the mechanism of inhibition of a key step in large ribosomal subunit formation. PMID:24371142

  17. 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

  18. Neurexin dysfunction in adult neurons results in autistic-like behavior in mice.

    PubMed

    Rabaneda, Luis G; Robles-Lanuza, Estefanía; Nieto-González, José Luis; Scholl, Francisco G

    2014-07-24

    Autism spectrum disorders (ASDs) comprise a group of clinical phenotypes characterized by repetitive behavior and social and communication deficits. Autism is generally viewed as a neurodevelopmental disorder where insults during embryonic or early postnatal periods result in aberrant wiring and function of neuronal circuits. Neurexins are synaptic proteins associated with autism. Here, we generated transgenic βNrx1ΔC mice in which neurexin function is selectively impaired during late postnatal stages. Whole-cell recordings in cortical neurons show an impairment of glutamatergic synaptic transmission in the βNrx1ΔC mice. Importantly, mutant mice exhibit autism-related symptoms, such as increased self-grooming, deficits in social interactions, and altered interaction for nonsocial olfactory cues. The autistic-like phenotype of βNrx1ΔC mice can be reversed after removing the mutant protein in aged animals. The defects resulting from disruption of neurexin function after the completion of embryonic and early postnatal development suggest that functional impairment of mature circuits can trigger autism-related phenotypes.

  19. 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

  20. Acute stress enhances adult rat hippocampal neurogenesis and activation of newborn neurons via secreted astrocytic FGF2.

    PubMed

    Kirby, Elizabeth D; Muroy, Sandra E; Sun, Wayne G; Covarrubias, David; Leong, Megan J; Barchas, Laurel A; Kaufer, Daniela

    2013-04-16

    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.

  1. Network Modeling of Adult Neurogenesis: Shifting Rates of Neuronal Turnover Optimally Gears Network Learning according to Novelty Gradient

    PubMed Central

    Chambers, R. Andrew; Conroy, Susan K.

    2010-01-01

    Apoptotic and neurogenic events in the adult hippocampus are hypothesized to play a role in cognitive responses to new contexts. Corticosteroid-mediated stress responses and other neural processes invoked by substantially novel contextual changes may regulate these processes. Using elementary three-layer neural networks that learn by incremental synaptic plasticity, we explored whether the cognitive effects of differential regimens of neuronal turnover depend on the environmental context in terms of the degree of novelty in the new information to be learned. In “adult” networks that had achieved mature synaptic connectivity upon prior learning of the Roman alphabet, imposition of apoptosis/neurogenesis before learning increasingly novel information (alternate Roman < Russian < Hebrew) reveals optimality of informatic cost benefits when rates of turnover are geared in proportion to the degree of novelty. These findings predict that flexible control of rates of apoptosis–neurogenesis within plastic, mature neural systems optimizes learning attributes under varying degrees of contextual change, and that failures in this regulation may define a role for adult hippocampal neurogenesis in novelty- and stress-responsive psychiatric disorders. PMID:17214558

  2. NF-κB mediated enhancement of potassium currents by the chemokine CXCL1/growth related oncogene in small diameter rat sensory neurons

    PubMed Central

    Yang, Rui-Hua; Strong, Judith A; Zhang, Jun-Ming

    2009-01-01

    Background Inflammatory processes play important roles in both neuropathic and inflammatory pain states, but the effects of inflammation per se within the sensory ganglia are not well understood. The cytokine growth-related oncogene (GRO/KC; CXCL1) shows strong, rapid upregulation in dorsal root ganglion (DRG) in both nerve injury and inflammatory pain models. We examined the direct effects of GRO/KC on small diameter DRG neurons, which are predominantly nociceptive. Whole cell voltage clamp technique was used to measure voltage-activated potassium (K) currents in acutely cultured adult rat small diameter sensory neurons. Fluorescently labeled isolectin B4 (IB4) was used to classify cells as IB4-positive or IB4-negative. Results In IB4-negative neurons, voltage-activated K current densities of both transient and sustained components were increased after overnight incubation with GRO/KC (1.5 nM), without marked changes in voltage dependence or kinetics. The average values for the slow and fast decay time constants at 20 mV were unchanged by GRO/KC. The amplitude of the fast inactivating component increased significantly with no large shifts in the voltage dependence of inactivation. The increase in K currents was completely blocked by co-incubation with protein synthesis inhibitor cycloheximide (CHX) or NF-κB inhibitors pyrrolidine dithiocarbamate (PDTC) or quinazoline (6-Amino-4-(4-phenoxypheny lethylamino;QNZ). In contrast, the voltage-activated K current of IB4-positive neurons was unchanged by GRO/KC. GRO/KC incubation caused no significant changes in the expression level of eight selected voltage-gated K channel genes in quantitative PCR analysis. Conclusion The results suggest that GRO/KC has important effects in inflammatory processes via its direct actions on sensory neurons, and that activation of NF-κB is involved in the GRO/KC-induced enhancement of K currents. PMID:19476648

  3. Prostaglandin E2/EP4 signalling facilitates EP4 receptor externalization in primary sensory neurons in vitro and in vivo.

    PubMed

    St-Jacques, Bruno; Ma, Weiya

    2013-02-01

    Inflammatory pain severely affects the quality of life of millions of individuals worldwide. Prostaglandin E2 (PGE2), a pain mediator enriched in inflamed tissues, plays a pivotal role in nociceptor sensitization and in the genesis of inflammatory pain. Its EP4 receptor mainly mediates its role in inflammatory pain. However, the underlying mechanisms are poorly understood. Here we found that PGE2/EP4 signalling-induced EP4 externalization in dorsal root ganglion (DRG) neurons contributes to nociceptor sensitization and inflammatory pain. In cultured DRG neurons, PGE2 and the EP4 agonist concentration- and time-dependently stimulated EP4 externalization. The inhibitors of anterograde secretory pathway, protein synthesis, or recycling pathway suppressed PGE2-induced EP4 externalization, suggesting that EP4 retained in Golgi apparatus and in recycling endosomes, as well as newly synthesized, are mobilized in this event. Interestingly, the intracellular cAMP levels of cultured DRG explants following 2 sequential treatments with the EP4 agonist were significantly higher than a single treatment, suggesting that the first treatment of agonist likely induces EP4 export to sensitize DRG neurons. Intraplantar injection of complete Freud's adjuvant increases both total and cell-surface EP4 levels of L4-6 DRG neurons, an event suppressed by a cyclooxygenase-2 inhibitor or a selective EP4 antagonist, suggesting that PGE2/EP4 signalling in inflamed paw contributes to EP4 synthesis and export in DRG neurons, thus sensitizing nociceptors during inflammation. We conclude that PGE2/EP4 signalling-induced EP4 externalization in DRG neuron is a novel mechanism underlying nociceptor sensitization and inflammatory pain. Blocking EP4 externalization could open a novel therapeutic avenue to treat inflammatory pain.

  4. Postnatal day 7 ethanol treatment causes persistent reductions in adult mouse brain volume and cortical neurons with sex specific effects on neurogenesis.

    PubMed

    Coleman, Leon G; Oguz, Ipek; Lee, Joohwi; Styner, Martin; Crews, Fulton T

    2012-09-01

    Ethanol treatment on postnatal day seven (P7) causes robust brain cell death and is a model of late gestational alcohol exposure (Ikonomidou et al., 2000). To investigate the long-term effects of P7 ethanol treatment on adult brain, mice received either two doses of saline or ethanol on P7 (2.5 g/kg, s.c., 2 h apart) and were assessed as adults (P82) for brain volume (using postmortem MRI) and cellular architecture (using immunohistochemistry). Adult mice that received P7 ethanol had reduced MRI total brain volume (4%) with multiple brain regions being reduced in both males and females. Immunohistochemistry indicated reduced frontal cortical parvalbumin immunoreactive (PV + IR) interneurons (18-33%) and reduced Cux1+IR layer II pyramidal neurons (15%) in both sexes. Interestingly, markers of adult hippocampal neurogenesis differed between sexes, with only ethanol treated males showing increased doublecortin and Ki67 expression (52 and 57% respectively) in the dentate gyrus, consistent with increased neurogenesis compared to controls. These findings suggest that P7 ethanol treatment causes persistent reductions in adult brain volume and frontal cortical neurons in both males and females. Increased adult neurogenesis in males, but not females, is consistent with differential adaptive responses to P7 ethanol toxicity between the sexes. One day of ethanol exposure, e.g. P7, causes persistent adult brain dysmorphology.

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

    PubMed Central

    Wang, Jun-Gang; Strong, Judith A; Xie, Wenrui; Yang, Rui-Hua; Coyle, Dennis E; Wick, Dayna M; Dorsey, Ericka D; Zhang, Jun-Ming

    2008-01-01

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

  6. Regulation of expression of the sensory neuron-specific sodium channel SNS in inflammatory and neuropathic pain.

    PubMed

    Okuse, K; Chaplan, S R; McMahon, S B; Luo, Z D; Calcutt, N A; Scott, B P; Akopian, A N; Wood, J N

    1997-01-01

    Increased voltage-gated sodium channel activity may contribute to the hyperexcitability of sensory neurons in inflammatory and neuropathic pain states. We examined the levels of the transcript encoding the tetrodotoxin-resistant sodium channel SNS in dorsal root ganglion neurons in a range of inflammatory and neuropathic pain models in the rat. Local Freund's adjuvant or systemic nerve growth factor-induced inflammation did not substantially alter the total levels of SNS mRNA. When NGF-treated adult rat DRG neurons in vitro were compared with NGF-depleted control neurons, SNS total mRNA levels and the levels of membrane-associated immunoreactive SNS showed a small increase (17 and 25%, respectively), while CGRP levels increased fourfold. SNS expression is thus little dependent on NGF even though SNS transcript levels dropped by more than 60% 7-14 days after axotomy. In the streptozotocin diabetic rat SNS levels fell 25%, while in several manipulations of the L5/6 tight nerve ligation rat neuropathic pain model, SNS levels fell 40-80% in rat strains that are either susceptible or relatively resistant to the development of allodynia. Increased expression of SNS mRNA is thus unlikely to underlie sensory neuron hyperexcitability associated with inflammation, while lowered SNS transcript levels are associated with peripheral nerve damage. PMID:9532581

  7. Characterization of prostanoid receptor-evoked responses in rat sensory neurones

    PubMed Central

    Smith, Jacqueline A M; Amagasu, Shanti M; Eglen, Richard M; Hunter, John C; Bley, Keith R

    1998-01-01

    Prostanoid receptor-mediated sensitization, or excitation, of sensory nerve fibres contributes to the generation of hyperalgesia. To characterize the prostanoid receptors present on sensory neurones, biochemical assays were performed on primary cultures of adult rat dorsal root ganglia (DRG) and the F-11 (embryonic rat DRG×neuroblastoma hybrid) cell line.In DRG cultures, the IP receptor agonists, cicaprost and carbaprostacyclin (cPGI2) stimulated cyclic AMP accumulation. Prostaglandin E2 (PGE2) also increased cyclic AMP levels, but to a lesser extent, while carbocyclic thromboxane A2 (cTxA2), PGD2 and PGF2α had negligible effects. The rank order of agonist potency was cicaprost >PGE2=BMY45778=cPGI2=PGI2. In the F-11 cells, the rank order of agonist potency for the stimulation of cyclic AMP accumulation was: cicaprost>iloprost=cPGI2=PGI2=BMY45778>PGE2=cTXA2. In DRG cultures, cicaprost induced significantly more accumulation of inositol phosphates than PGE2.To examine the effects of prostanoids on C-fibre activity, extracellular recordings of d.c. potentials from the rat isolated vagus nerve were made with the ‘grease-gap' technique. PGI2 (0.1 nM–10 μM) produced the largest depolarizations of the nerve. The rank order of agonist potency was: PGI2=cPGI2=PGE1>cTXA2>PGE2=PGD2=TXB2>PGF2α.Prior depolarization of nerves with either forskolin (10 μM) or phorbol dibutyrate (1 μM) alone significantly reduced the response to PGI2 (10 μM), while simultaneous application of both forskolin and phorbol dibutyrate attenuated PGI2 responses almost completely.Putative EP1 and/or TP receptor-selective antagonists had no effect on the responses to PGI2, cPGI2 or PGE2 in the three preparations studied.Collectively, these data are consistent with a positive coupling of IP receptors to both adenylyl cyclase and phospholipase C in sensory neurones. These findings suggest that IP receptors play a major role in the sensitization of rat sensory neurones. PMID:9647476

  8. 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.

  9. Propofol and AZD3043 Inhibit Adult Muscle and Neuronal Nicotinic Acetylcholine Receptors Expressed in Xenopus Oocytes.

    PubMed

    Jonsson Fagerlund, Malin; Krupp, Johannes; Dabrowski, Michael A

    2016-02-06

    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.

  10. 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

  11. 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.

  12. 42 CFR 412.10 - Changes in the DRG classification system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... classification system published in accordance with paragraph (a) of this section. (e) Review by ProPAC. Changes...PAC upon publication. Interim changes to the DRG classification system that are made in accordance with paragraphs (c) and (d) of this section are subject to review by ProPAC before implementation....

  13. 42 CFR 412.10 - Changes in the DRG classification system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... classification system published in accordance with paragraph (a) of this section. (e) Review by ProPAC. Changes...PAC upon publication. Interim changes to the DRG classification system that are made in accordance with paragraphs (c) and (d) of this section are subject to review by ProPAC before implementation....

  14. 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... SERVICES (CONTINUED) QUALITY IMPROVEMENT ORGANIZATIONS UTILIZATION AND QUALITY CONTROL REVIEW Review Responsibilities of Utilization and Quality Control Quality Improvement Organizations (QIOs) Qio Review...

  15. Proteinase-activated receptor-1 activation presynaptically enhances spontaneous glutamatergic excitatory transmission in adult rat substantia gelatinosa neurons.

    PubMed

    Fujita, T; Liu, T; Nakatsuka, T; Kumamoto, E

    2009-07-01

    Proteinase-activated receptors (PARs) have a unique activation mechanism in that a proteolytically exposed N-terminal region acts as a tethered ligand. A potential impact of PAR on sensory processing has not been fully examined yet. Here we report that synthetic peptides with sequences corresponding to PAR ligands enhance glutamatergic excitatory transmission in substantia gelatinosa (SG) neurons of adult rat spinal cord slices by using the whole cell patch-clamp technique. The frequency of spontaneous excitatory postsynaptic current (EPSC) was increased by PAR-1 agonist SFLLRN-NH2 (by 47% at 1 microM) with small increases by PAR-2 and -4 agonists (SLIGKV-NH2 and GYPGQV-OH, respectively; at >3 microM); there was no change in its amplitude or in holding current at -70 mV. The PAR-1 peptide action was inhibited by PAR-1 antagonist YFLLRNP-OH. TFLLR-NH2, an agonist which is more selective to PAR-1 than SFLLRN-NH2, dose-dependently increased spontaneous EPSC frequency (EC50=0.32 microM). A similar presynaptic effect was produced by PAR-1 activating proteinase thrombin in a manner sensitive to YFLLRNP-OH. The PAR-1 peptide action was resistant to tetrodotoxin and inhibited in Ca2+-free solution. Primary-afferent monosynaptically evoked EPSC amplitudes were unaffected by PAR-1 agonist. These results indicate that PAR-1 activation increases the spontaneous release of L-glutamate onto SG neurons from nerve terminals in a manner dependent on extracellular Ca2+. Considering that sensory processing within the SG plays a pivotal role in regulating nociceptive transmission to the spinal dorsal horn, the PAR-1-mediated glutamatergic transmission enhancement could be involved in a positive modulation of nociceptive transmission. PMID:19420120

  16. 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

  17. 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

  18. [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

  19. 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.

  20. 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

  1. 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

  2. Adult Neurogenesis in the Female Mouse Hypothalamus: Estradiol and High-Fat Diet Alter the Generation of Newborn Neurons Expressing Estrogen Receptor α

    PubMed Central

    Yang, Jane; Nettles, Sabin A.; Byrnes, Elizabeth M.

    2016-01-01

    Estrogens and leptins act in the hypothalamus to maintain reproduction and energy homeostasis. Neurogenesis in the adult mammalian hypothalamus has been implicated in the regulation of energy homeostasis. Recently, high-fat diet (HFD) and estradiol (E2) have been shown to alter cell proliferation and the number of newborn leptin-responsive neurons in the hypothalamus of adult female mice. The current study tested the hypothesis that new cells expressing estrogen receptor α (ERα) are generated in the arcuate nucleus (ARC) and the ventromedial nucleus of the hypothalamus (VMH) of the adult female mouse, hypothalamic regions that are critical in energy homeostasis. Adult mice were ovariectomized and implanted with capsules containing E2 or oil. Within each hormone group, mice were fed an HFD or standard chow for 6 weeks and treated with BrdU to label new cells. Newborn cells that respond to estrogens were identified in the ARC and VMH, of which a subpopulation was leptin sensitive, indicating that the subpopulation consists of neurons. Moreover, there was an interaction between diet and hormone with an effect on the number of these newborn ERα-expressing neurons that respond to leptin. Regardless of hormone treatment, HFD increased the number of ERα-expressing cells in the ARC and VMH. E2 decreased hypothalamic fibroblast growth factor 10 (Fgf10) gene expression in HFD mice, suggesting a role for Fgf10 in E2 effects on neurogenesis. These findings of newly created estrogen-responsive neurons in the adult brain provide a novel mechanism by which estrogens can act in the hypothalamus to regulate energy homeostasis in females. PMID:27679811

  3. Adult Neurogenesis in the Female Mouse Hypothalamus: Estradiol and High-Fat Diet Alter the Generation of Newborn Neurons Expressing Estrogen Receptor α

    PubMed Central

    Yang, Jane; Nettles, Sabin A.; Byrnes, Elizabeth M.

    2016-01-01

    Estrogens and leptins act in the hypothalamus to maintain reproduction and energy homeostasis. Neurogenesis in the adult mammalian hypothalamus has been implicated in the regulation of energy homeostasis. Recently, high-fat diet (HFD) and estradiol (E2) have been shown to alter cell proliferation and the number of newborn leptin-responsive neurons in the hypothalamus of adult female mice. The current study tested the hypothesis that new cells expressing estrogen receptor α (ERα) are generated in the arcuate nucleus (ARC) and the ventromedial nucleus of the hypothalamus (VMH) of the adult female mouse, hypothalamic regions that are critical in energy homeostasis. Adult mice were ovariectomized and implanted with capsules containing E2 or oil. Within each hormone group, mice were fed an HFD or standard chow for 6 weeks and treated with BrdU to label new cells. Newborn cells that respond to estrogens were identified in the ARC and VMH, of which a subpopulation was leptin sensitive, indicating that the subpopulation consists of neurons. Moreover, there was an interaction between diet and hormone with an effect on the number of these newborn ERα-expressing neurons that respond to leptin. Regardless of hormone treatment, HFD increased the number of ERα-expressing cells in the ARC and VMH. E2 decreased hypothalamic fibroblast growth factor 10 (Fgf10) gene expression in HFD mice, suggesting a role for Fgf10 in E2 effects on neurogenesis. These findings of newly created estrogen-responsive neurons in the adult brain provide a novel mechanism by which estrogens can act in the hypothalamus to regulate energy homeostasis in females.

  4. 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

  5. Olfactory neuron loss in adult male CD rats following subchronic inhalation exposure to hydrogen sulfide.

    PubMed

    Brenneman, K A; James, R A; Gross, E A; Dorman, D C

    2000-01-01

    Dysosmia and anosmia are reported to occur following human exposure to hydrogen sulfide (H2S) gas. The clinical association between H2S exposure and olfactory dysfunction in humans necessitates evaluation of the nasal cavity and olfactory system in experimental animals used to study H2S toxicity. The purpose of this study was to subchronically expose 10-week-old male CD rats to relatively low concentrations of H2S and to histologically evaluate the nasal cavity for exposure-related lesions. Rats (n = 12/group) were exposed via inhalation to 0, 10, 30, or 80 ppm H2S 6 h/d and 7 d/wk for 10 weeks. Following exposure to 30 and 80 ppm H2S, a significant increase in nasal lesions limited to the olfactory mucosa was observed. The lesions, which consisted of olfactory neuron loss and basal cell hyperplasia, were multifocal, bilaterally symmetrical, and had a characteristic rostrocaudal distribution pattern. Regions of the nasal cavity affected included the dorsal medial meatus and the dorsal and medial portions of the ethmoid recess. The no observed adverse effect level for olfactory lesions in this study was 10 ppm. For perspective, the American Conference of Governmental Industrial Hygienists threshold limit value (TLV) recommendation for H2S is currently 10 ppm (proposed revision: 5 ppm), so the concentrations employed in the present study were 3 and 8 times the TLV. These findings suggest that subchronic inhalation exposure to a relatively low level of H2S (30 ppm) can result in olfactory toxicity in rats. However, because of differences in the breathing style and nasal anatomy of rats and humans, additional research is required to determine the significance of these results for human health risk assessment.

  6. 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.

  7. The properties, distribution and function of Na+–Ca2+ exchanger isoforms in rat cutaneous sensory neurons

    PubMed Central

    Scheff, N N; Yilmaz, E; Gold, M S

    2014-01-01

    The Na+–Ca2+ exchanger (NCX) appears to play an important role in the regulation of the high K+-evoked Ca2+ transient in putative nociceptive dorsal root ganglion (DRG) neurons. The purpose of the present study was to (1) characterize the properties of NCX activity in subpopulations of DRG neurons, (2) identify the isoform(s) underlying NCX activity, and (3) begin to assess the function of the isoform(s) in vivo. In retrogradely labelled neurons from the glabrous skin of adult male Sprague–Dawley rats, NCX activity, as assessed with fura-2-based microfluorimetry, was only detected in putative nociceptive IB4+ neurons. There were two modes of NCX activity: one was evoked in response to relatively large and long lasting (∼325 nm for >12 s) increases in the concentration of intracellular Ca2+ ([Ca2+]i), and a second was active at resting [Ca2+]i > ∼150 nm. There also were two modes of evoked activity: one that decayed relatively rapidly (<5 min) and a second that persisted (>10 min). Whereas mRNA encoding all three NCX isoforms (NCX1–3) was detected in putative nociceptive cutaneous neurons with single cell PCR, pharmacological analysis and small interfering RNA (siRNA) knockdown of each isoform in vivo suggested that NCX2 and 3 were responsible for NCX activity. Western blot analyses suggested that NCX isoforms were differentially distributed within sensory neurons. Functional assays of excitability, action potential propagation, and nociceptive behaviour suggest NCX activity has little influence on excitability per se, but instead influences axonal conduction velocity, resting membrane potential, and nociceptive threshold. Together these results indicate that the function of NCX in the regulation of [Ca2+]i in putative nociceptive neurons may be unique relative to other cells in which these exchanger isoforms have been characterized and it has the potential to influence sensory neuron properties at multiple levels. PMID:25239455

  8. Heterogeneity of European DRG systems and potentials for a common EuroDRG system Comment on "Cholecystectomy and Diagnosis-Related Groups (DRGs): patient classification and hospital reimbursement in 11 European countries".

    PubMed

    Geissler, Alexander; Quentin, Wilm; Busse, Reinhard

    2015-05-01

    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

  9. Heterogeneity of European DRG systems and potentials for a common EuroDRG system Comment on "Cholecystectomy and Diagnosis-Related Groups (DRGs): patient classification and hospital reimbursement in 11 European countries".

    PubMed

    Geissler, Alexander; Quentin, Wilm; Busse, Reinhard

    2015-03-05

    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.

  10. 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

  11. 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

  12. Mapping of fluorescent protein-expressing neurons and axon pathways in adult and developing Thy1-eYFP-H transgenic mice.

    PubMed

    Porrero, Cesar; Rubio-Garrido, Pablo; Avendaño, Carlos; Clascá, Francisco

    2010-07-23

    Transgenic mouse lines in which a fluorescent protein is constitutively expressed under the Thy1 gene promoter have become important models in cell biology and pathology studies of specific neuronal populations. As a result of positional insertion and/or copy number effects on the transgene, the populations expressing the fluorescent protein (eYFP+) vary markedly among the different mice lines. However, identification of the eYFP+ subpopulations has remained sketchy and fragmentary even for the most widely used lines such as Thy1-eYFP-H mice (Feng, G., Mellor, R.H., Bernstein, M., Keller-Peck, C., Nguyen, Q.T., Wallace, M., Nerbonne, J.M., Lichtman and J.W., Sanes. J.R. 2000. Imaging neuronal subsets in transgenic mice expressing multiple spectral variants of GFP. Neuron 28, 41-51). Here, we provide a comprehensive mapping of labeled cell types throughout the central nervous system in adult and postnatal (P0-P30) Thy1-eYFP-H mice. Cell type identification was based on somatodendritic morphology, axon trajectories, and, for cortical cells, retrograde labeling with Fast Blue to distinguish between subpopulations with different axonal targets. In the neocortex, eYFP+ cells are layers 5 and 6 pyramidal neurons, whose abundance and sublaminar distribution varies markedly between areas. Labeling is particularly prevalent in the corticospinal cells; as a result, the pyramidal pathway axons are conspicuously labeled down to the spinal cord. Large populations of hippocampal, subicular and amygdaloid projection neurons are eYFP+ as well. Additional eYFP+ cell groups are located in specific brainstem nuclei. Present results provide a comprehensive reference dataset for adult and developmental studies using the Thy1-eYFP-H mice strain, and show that this animal model may be particularly suitable for studies on the cell biology of corticospinal neurons.

  13. 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.

  14. Role of the neuronal histaminergic system in the regulation of somatotropic function: comparison between the neonatal and the adult rat.

    PubMed

    Grilli, R; Sibilia, V; Torsello, A; Pagani, F; Guidi, M; Luoni, M; Netti, C; Müller, E E

    1996-11-01

    To study possible age-related differences in the role of neuronal histaminergic pathways in the control of GH secretion, the effects of alpha-fluoromethylhistidine (alpha-FMH), an irreversible inhibitor of histamine (HA) synthesis, were examined on basal and opioid-induced GH release in neonatal and adult rats. The mechanisms involved in such effects were evaluated by measuring pituitary GH mRNA levels and hypothalamic levels of GH-releasing hormone (GHRH) and somatostatin (SRIF) mRNAs. Daily injection of alpha-FMH (20 mg/kg, s.c.) in pups of either sex, from birth until 10 days of age, caused a significant increase in baseline plasma GH and potentiated the GH response to the [Met5]-enkephalin analog FK 33-824 (1 mg/kg, s.c.) administered 3 h after the last alpha-FMH injection. GH and SRIF mRNA levels were significantly higher in alpha-FMH-treated pups than in controls, whereas no difference was observed in GHRH mRNA levels. In young adult male rats, acute administration of alpha-FMH (100 mg/kg, s.c., 3 h before) did not change significantly basal GH levels but potentiated FK 33-824 (0.3 mg/kg, intracarotid)-induced stimulation of GH secretion. Repeated administration of alpha-FMH (200 micrograms/rat, i.c.v., for 3 days) failed to modify basal and FK 33-824-induced GH secretion, caused a significant reduction in hypothalamic GHRH mRNA levels and left SRIF and GH mRNAs unchanged. These findings indicate that HA exerts an inhibitory effect on GH secretion in both neonatal and adult rats. The different effects of short-term HA depletion on hypothalamic and pituitary indices of somatotropic function observed at the two age periods may be ascribed to the immaturity of the HA system in early postnatal life and to a different functional role of GH-regulatory factors during ontogeny.

  15. [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

  16. [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

  17. 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

  18. 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

  19. Purification of Dorsal Root Ganglion Neurons from Rat by Immunopanning

    PubMed Central

    Zuchero, J. Bradley

    2015-01-01

    Dorsal root ganglion neurons (DRGs) are sensory neurons that facilitate somatosensation and have been used to study neurite outgrowth, regeneration, and degeneration and PNS and CNS myelination. Studies of DRGs have relied on cell isolation strategies that generally involve extended culture in the presence of antimitotic agents or other cytotoxic treatments that target dividing cells. The surviving cells typically are dependent on serum for growth. Other methods, involving purification of DRGs based on their large size, produce low yield. In contrast, the immunopanning-based method described here for prospective isolation of DRGs from rodents allows for rapid purification in the absence of antimitotic agents and serum. These DRG cultures take place in a defined medium. They are free of Schwann cells and other glia and thus can be used to study the role of glia in the biology of DRG neurons. PMID:25086011

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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

  5. Calbindin-immunoreactive sensory neurons in dissociated dorsal root ganglion cell cultures of chick embryo: role of culture conditions.

    PubMed

    Barakat, I; Droz, B

    1989-12-01

    Immunoreactivity to calbindin D-28k, a vitamin D-dependent calcium-binding protein, is expressed by neuronal subpopulations of dorsal root ganglia (DRG) in the chick embryo. To determine whether the expression of this phenotypic characteristic is maintained in vitro and controlled by environmental factors, dissociated DRG cell cultures were performed under various conditions. Subpopulations of DRG cells cultured at embryonic day 10 displayed calbindin-immunoreactive cell bodies and neurites in both neuron-enriched or mixed DRG cell cultures. The number of calbindin-immunoreactive ganglion cells increased up to 7-10 days of culture independently of the changes occurring in the whole neuronal population. The presence of non-neuronal cells, which promotes the maturation of the sensory neurons, tended to reduce the percentage of calbindin-immunoreactive cell bodies. Addition of horse serum enhanced both the number of calbindin-positive neurons and the intensity of the immunostaining, but does not prevent the decline of the subpopulation of calbindin-immunoreactive neurons during the second week of culture; on the contrary, the addition of muscular extract to cultures at 10 days maintained the number of calbindin-expressing neurons. While calbindin-immunoreactive cell bodies grown in culture were small- or medium-sized, no correlation was found between cell size and immunostaining density. At the ultrastructural level, the calbindin immunoreaction was distributed throughout the neuroplasm. These results indicate that the expression of calbindin by sensory neurons grown in vitro may be modulated by horse serum-contained factors or interaction with non-neuronal cells. As distinct from horse serum, muscular extract is able to maintain the expression of calbindin by a subpopulation of DRG cells.

  6. Role of platinum DNA damage-induced transcriptional inhibition in chemotherapy-induced neuronal atrophy and peripheral neurotoxicity.

    PubMed

    Yan, Fang; Liu, Johnson J; Ip, Virginia; Jamieson, Stephen M F; McKeage, Mark J

    2015-12-01

    Platinum-based anticancer drugs cause peripheral neurotoxicity by damaging sensory neurons within the dorsal root ganglia (DRG), but the mechanisms are incompletely understood. The roles of platinum DNA binding, transcription inhibition and altered cell size were investigated in primary cultures of rat DRG cells. Click chemistry quantitative fluorescence imaging of RNA-incorporated 5-ethynyluridine showed high, but wide ranging, global levels of transcription in individual neurons that correlated with their cell body size. Treatment with platinum drugs reduced neuronal transcription and cell body size to an extent that corresponded to the amount of preceding platinum DNA binding, but without any loss of neuronal cells. The effects of platinum drugs on neuronal transcription and cell body size were inhibited by blocking platinum DNA binding with sodium thiosulfate, and mimicked by treatment with a model transcriptional inhibitor, actinomycin D. In vivo oxaliplatin treatment depleted the total RNA content of DRG tissue concurrently with altering DRG neuronal size. These findings point to a mechanism of chemotherapy-induced peripheral neurotoxicity, whereby platinum DNA damage induces global transcriptional arrest leading in turn to neuronal atrophy. DRG neurons may be particularly vulnerable to this mechanism of toxicity because of their requirements for high basal levels of global transcriptional activity. Findings point to a new stepwise mechanism of chemotherapy-induced peripheral neurotoxicity, whereby platinum DNA damage induces global transcriptional arrest leading in turn to neuronal atrophy. Dorsal root ganglion neurons may be particularly vulnerable to this neurotoxicity because of their high global transcriptional outputs, demonstrated in this study by click chemistry quantitative fluorescence imaging.

  7. Herpes Simplex Virus 1 Tropism for Human Sensory Ganglion Neurons in the Severe Combined Immunodeficiency Mouse Model of Neuropathogenesis

    PubMed Central

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

    2013-01-01

    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

  8. CXCL13/CXCR5 enhances sodium channel Nav1.8 current density via p38 MAP kinase in primary sensory neurons following inflammatory pain

    PubMed Central

    Wu, Xiao-Bo; Cao, De-Li; Zhang, Xin; Jiang, Bao-Chun; Zhao, Lin-Xia; Qian, Bin; Gao, Yong-Jing

    2016-01-01

    CXCL13 is a B lymphocyte chemoattractant and activates CXCR5 receptor in the immune system. Here we investigated whether CXCL13/CXCR5 mediates inflammatory pain in dorsal root ganglia (DRG) and the underlying mechanisms. Peripheral injection of complete Freund’s Adjuvant (CFA) increased the expression of CXCL13 and CXCR5 in DRG neurons. In Cxcr5−/− mice, CFA-induced pain hypersensitivity were attenuated. Whole-cell patch-clamp recording showed that the excitability of dissociated DRG neurons was increased after CFA injection or CXCL13 incubation from wild-type (WT) mice, but not from Cxcr5−/− mice. Additionally, sodium channel Nav1.8 was co-expressed with CXCR5 in dissociated DRG neurons, and the increased neuronal excitability induced by CFA or CXCL13 was reduced by Nav1.8 blocker. Intrathecal injection of Nav1.8 blocker also attenuated intrathecal injection of CXCL13-induced pain hypersensitivity. Furthermore, CXCL13 increased Nav1.8 current density in DRG neurons, which was inhibited by p38 MAP kinase inhibitor. CFA and CXCL13 increased p38 phosphorylation in the DRG of WT mice but not Cxcr5−/− mice. Finally, intrathecal p38 inhibitor alleviated CXCL13-induced pain hypersensitivity. Taken together, these results demonstrated that CXCL13, upregulated by peripheral inflammation, acts on CXCR5 on DRG neurons and activates p38, which increases Nav1.8 current density and further contributes to the maintenance of inflammatory pain. PMID:27708397

  9. 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.

  10. Investigating the expression of metabotropic glutamate receptors in trigeminal ganglion neurons and satellite glial cells: implications for craniofacial pain

    PubMed Central

    Boye Larsen, Dennis; Ingemann Kristensen, Gunda; Panchalingam, Vinodenee; Laursen, Jens Christian; Nørgaard Poulsen, Jeppe; Skallerup Andersen, Maria; Kandiah, Aginsha

    2014-01-01

    Context/objective Previous studies have demonstrated that various subtypes of the metabotropic glutamate receptors (mGluRs) are expressed in the dorsal root ganglion (DRG) of the peripheral nervous system (PNS), implicating that glutamate potentially contributes to sensory transmission through these receptors. While mGluR expression has been investigated largely in the DRG, the present study focused on mGluR expression on neurons and satellite glial cells (SGCs) of the trigeminal ganglion (TG). Materials and methods: To address the presence of mGluRs in rat TG neurons and their corresponding SGCs, the trigeminal ganglia from six adult male Wistar rats were isolated and immunohistochemistry and immunocytochemistry were performed. The expression of mGluR1α-, mGluR2/3- and mGluR8 on TG neurons and SGCs was investigated in tissue slices and isolated cells. Results: 35.1 ± 6.0% of the TG neurons were positive for mGluR1α, whereas 39.9 ± 7.7% and 55.5 ± 6.3% were positive for mGluR2/3 and mGluR8, respectively. Immunoreactive neurons expressing mGluRs were mainly medium- to large sized, with a smaller population of small-sized neurons showing immunoreactivity. The SGCs showed immunoreactivity toward mGluR1α and mGluR8, but not mGluR2/3, both in the tissue and in isolated cells. Conclusions: Findings from the present study showed that trigeminal neurons express mGluR1α, mGluR2/3 and mGluR8, while SGCs only express mGluR1α and mGluR8. This novel evidence may advance investigations on a possible role of mGluRs in relation to trigeminal pain transmission within the craniofacial region. PMID:24495291

  11. 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

  12. Impaired recruitment of seizure-generated neurons into functional memory networks of the adult dentate gyrus following long-term amygdala kindling.

    PubMed

    Fournier, Neil M; Botterill, Justin J; Marks, Wendie N; Guskjolen, Axel J; Kalynchuk, Lisa E

    2013-06-01

    Epileptic seizures increase the birth of new neurons in the adult hippocampus. Although the consequences of aberrant neurogenesis on behavior are not fully understood, one hypothesis is that seizure-generated neurons might form faulty circuits that disrupt hippocampal functions, such as learning and memory. In the present study, we employed long-term amygdala kindling (i.e., rats receive 99-electrical stimulations) to examine the effect of repeated seizures on hippocampal neurogenesis and behavior. We labeled seizure-generated cells with the proliferation marker BrdU after 30-stimulations and continued kindling for an additional 4weeks to allow newborn neurons to mature under conditions of repeated seizures. After kindling was complete, rats were tested in a trace fear conditioning task and sacrificed 2h later to examine if 4-week old newborn cells were recruited into circuits involved in the retrieval of emotional memory. Compared to non-kindled controls, long-term kindled rats showed significant impairments in fear memory reflected in a decrease in conditioned freezing to both tone and contextual cues during testing. Moreover, long-term kindling also prevented the activation of 4-week old newborn cells in response to fear memory retrieval. These results indicate that the presence of seizure activity during cell maturation impedes the ability of new neurons to integrate properly into circuits important in memory formation. Together, our findings suggest that aberrant seizure-induced neurogenesis might contribute to the development of learning impairments in chronic epilepsy and raise the possibility that targeting the reduced activation of adult born neurons could represent a beneficial strategy to reverse cognitive deficits in some epileptic patients.

  13. Medicare's DRG-weights in a European environment: the Spanish experience.

    PubMed

    Cots, F; Elvira, D; Castells, X; Dalmau, E

    2000-02-01

    Hospital payment systems are being changed to mixed systems, composed of case-mix categories and structure indicators. The Health Care Financing Administration's Diagnosis-Related-Groups (HCFA's DRG-weights are used in Catalonia as Prospective Payment System (PPS)-instruments for hospital inpatient reimbursement. The Catalonian and Spanish health systems, however, are very different from the US health environment. The aim of this study is to determine whether the HCFA's DRG-weights fit the special characteristics of a European environment. To do this, cost-based weights, determined from information from the cost accounting system of two public hospitals in Barcelona, are compared with Medicare-weights. A total of 35 262 discharges representing 12 794 million pesetas are analyzed. Medicare-weights do not differ globally from cost-based-weights and the adjusted correlation weighted least squares regression between the two weight-scales is 95%. There are, however, systematic deviations in six DRG-groupings. The most important deviations are concentrated in Ambulatory Surgery categories, in DRGs in which prostheses are used, and in specialties excluded from several PPSs because of extreme variables in treatment intensity. In conclusion, Medicare-weights can be used to pay hospital output in European environment but they should be adjusted to avoid systematic deviations. PMID:11010224

  14. The calcium-activated chloride channel anoctamin 1 acts as a heat sensor in nociceptive neurons.

    PubMed

    Cho, Hawon; Yang, Young Duk; Lee, Jesun; Lee, Byeongjoon; Kim, Tahnbee; Jang, Yongwoo; Back, Seung Keun; Na, Heung Sik; Harfe, Brian D; Wang, Fan; Raouf, Ramin; Wood, John N; Oh, Uhtaek

    2012-05-27

    Nociceptors are a subset of small primary afferent neurons that respond to noxious chemical, thermal and mechanical stimuli. Ion channels in nociceptors respond differently to noxious stimuli and generate electrical signals in different ways. Anoctamin 1 (ANO1 also known as TMEM16A) is a Ca(2+)-activated chloride channel that is essential for numerous physiological functions. We found that ANO1 was activated by temperatures over 44 °C with steep heat sensitivity. ANO1 was expressed in small sensory neurons and was highly colocalized with nociceptor markers, which suggests that it may be involved in nociception. Application of heat ramps to dorsal root ganglion (DRG) neurons elicited robust ANO1-dependent depolarization. Furthermore, knockdown or deletion of ANO1 in DRG neurons substantially reduced nociceptive behavior in thermal pain models. These results indicate that ANO1 is a heat sensor that detects nociceptive thermal stimuli in sensory neurons and possibly mediates nociception.

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

    PubMed

    Liu, Xiao-Dan; Yang, Jing-Jing; Fang, Dong; Cai, Jie; Wan, You; Xing, Guo-Gang

    2014-01-01

    We have previously reported that enhanced excitability of dorsal root ganglia (DRG) neurons contributes to the development of bone cancer pain, which severely decreases the quality of life of cancer patients. Nav1.8, a tetrodotoxin-resistant (TTX-R) sodium channel, contributes most of the sodium current underlying the action potential upstroke and accounts for most of the current in later spikes in a train. We speculate that the Nav1.8 sodium channel is a potential candidate responsible for the enhanced excitability of DRG neurons in rats with bone cancer pain. Here, using electrophysiology, Western blot and behavior assays, we documented that the current density of TTX-R sodium channels, especially the Nav1.8 channel, increased significantly in DRG neurons of rats with cancer-induced bone pain. This increase may be due to an increased expression of Nav1.8 on the membrane of DRG neurons. Accordantly, blockade of Nav1.8 sodium channels by its selective blocker A-803467 significantly alleviated the cancer-induced mechanical allodynia and thermal hyperalgesia in rats. Taken together, these results suggest that functional upregulation of Nav1.8 channels on the membrane of DRG neurons contributes to the development of cancer-induced bone pain. PMID:25503076

  16. A pyridinium derivative from Red Sea soft corals inhibited voltage-activated potassium conductances and increased excitability of rat cultured sensory neurones

    PubMed Central

    Temraz, Tarek A; Houssen, Wael E; Jaspars, Marcel; Woolley, David R; Wease, Kerrie N; Davies, Steven N; Scott, Roderick H

    2006-01-01

    Background Whole cell patch clamp recording and intracellular Ca2+ imaging were carried out on rat cultured dorsal root ganglion (DRG) neurones to characterize the actions of crude extracts and purified samples from Red Sea soft corals. The aim of the project was to identify compounds that would alter the excitability of DRG neurones. Results Crude extracts of Sarcophyton glaucum and Lobophyton crassum attenuated spike frequency adaptation causing DRG neurones to switch from firing single action potentials to multiple firing. The increase in excitability was associated with enhanced KCl-evoked Ca2+ influx. The mechanism of action of the natural products in the samples from the soft corals involved inhibition of voltage-activated K+ currents. An active component of the crude marine samples was identified as 3-carboxy-1-methyl pyridinium (trigonelline). Application of synthetic 3-carboxy-1-methyl pyridinium at high concentration (0.1 mM) also induced multiple firing and reduced voltage-activated K+ current. The changes in excitability of DRG neurones induced by 3-carboxy-1-methyl pyridinium suggest that this compound contributes to the bioactivity produced by the crude extracts from two soft corals. Conclusion Sarcophyton glaucum and Lobophyton crassum contain natural products including 3-carboxy-1-methyl pyridinium that increase the excitability of DRG neurones. We speculate that in addition to developmental control and osmoregulation these compounds may contribute to chemical defenses. PMID:16824204

  17. [Comparison of hand surgery in the German and Italian DRG systems].

    PubMed

    Lotter, O; Dolderer, J; Stahl, S; Atzei, A; Haerle, M; Schaller, H E

    2011-12-01

    Diagnosis-related groups (DRGs) are a patient classification system grouping related types of patients treated to the resources they consumed. In this analysis we compared the Italian and the German DRG systems regarding hand surgery with an emphasis on reimbursement of clinical cases. The 15 most common hand surgical diagnoses and their corresponding operative treatment in our clinic in 2009 were processed using a DRG grouper. The underlying data were transferred to the Italian system. Thus, the length of stay and the reimbursement of both countries could be obtained and compared. The latter was adjusted and corrected by the purchasing power of each country. The mean of the upper threshold of length of stay was 10 days in the German as well as the Italian system whereas the median was 2 times higher in Italy (6 vs. 12 days). Fifteen out of 19 cases showed higher reimbursement in Germany. The case mix index (CMI) of 0.917 in Germany represents a mean payment of 2,676 € per case. In Italy the hypothetical CMI of 0.635 resulted in a mean reimbursement of 1,853 € per case. The biggest difference in remuneration could be found for replantation of multiple fingers. For this service the German health-care system pays 12,320 € more than the Italian. Total proceeds of the top 15 diagnoses applying the number of cases treated in our clinic revealed 1.7 million € in the German and 1.2 million € in the Italian DRG system. Considering the purchasing power utilizing consumer prize parities, the difference of reimbursement between the countries decreased to 300,000 €. There is no mean length of stay per DRG in Italy, only the upper threshold of length of stay is determined. In most cases the latter is higher in Italy compared to Germany. The consumption of resources for finger replantation is not adequately represented in the Italian DRG system compared to finger amputation. Reimbursement of inpatient care is influenced by multiple factors not being subject

  18. 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

  19. 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.

  20. 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

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

    PubMed

    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 (I(A)) has remained hypothetical. Kv4 channels may underlie the I(A) in DRG neurons. We combined electrophysiology, molecular biology (Whole-Tissue and Single-Cell RT-PCR) and immunohistochemistry to investigate the molecular basis of the I(A) 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) I(A). Matching Kv4 channel properties, activation and inactivation of this I(A) 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 ( approximately 30 mum) 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 I(A) 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

  2. Re-evaluation of the phenotypic changes in L4 dorsal root ganglion neurons after L5 spinal nerve ligation.

    PubMed

    Fukuoka, Tetsuo; Yamanaka, Hiroki; Kobayashi, Kimiko; Okubo, Masamichi; Miyoshi, Kan; Dai, Yi; Noguchi, Koichi

    2012-01-01

    The L5 spinal nerve ligation (SNL) is a widely used animal neuropathic pain model. There are conflicting reports regarding the extent of injury to the L4 dorsal root ganglion (DRG) neurons in this model. If a significant number of these neurons were injured, the previously reported phenotypic and electrophysiological changes at this level are in need of re-evaluation by separating the injured neurons and the frankly spared ones. So, we immunostained activating transcription factor 3 (ATF3) and examined the change in expression of transcripts for neuropeptide Y (NPY), brain-derived neurotrophic factor (BDNF) and several voltage-gated sodium channel α-subunits (Nav1.1, Nav1.3, Nav1.6, Nav1.7, Nav1.8, and Nav1.9) in the L4 DRG by comparing signal intensities of individual neurons using in situ hybridization histochemistry. ATF3-immunoreactivity was similarly observed in 4-6% of neuronal nuclei of the SNL and sham-operated ipsilateral L4 DRGs. Comparison between ATF3+ and ATF3- neurons in the SNL L4 DRG revealed that (1) whereas NPY induction occurred in ATF3+ cells, BDNF increased mainly in ATF3- neurons; (2) although ATF3+ neurons had higher Nav1.3 signals than ATF3- neurons, these signals were much lower than those of the L5 DRG neurons; and (3) ATF3+/N52- neurons selectively lost Nav1.8 and Nav1.9 mRNAs. Comparison of the total neuronal populations among naïve, SNL, and sham-operated rats revealed no significant differences for all examined Nav mRNAs. Because neuropathic pain behaviors were developed by rats with SNL but not the sham-operation, the small number of injured L4 neurons likely do not contribute to the pathomechanisms of neuropathic pain. PMID:22054598

  3. 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.

  4. 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

  5. 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

  6. The chemokine CCL2 increases Nav1.8 sodium channel activity in primary sensory neurons through a Gβγ-dependent mechanism.

    PubMed

    Belkouch, Mounir; Dansereau, Marc-André; Réaux-Le Goazigo, Annabelle; Van Steenwinckel, Juliette; Beaudet, Nicolas; Chraibi, Ahmed; Melik-Parsadaniantz, Stéphane; Sarret, Philippe

    2011-12-14

    Changes in function of voltage-gated sodium channels in nociceptive primary sensory neurons participate in the development of peripheral hyperexcitability that occurs in neuropathic and inflammatory chronic pain conditions. Among them, the tetrodotoxin-resistant (TTX-R) sodium channel Na(v)1.8, primarily expressed by small- and medium-sized dorsal root ganglion (DRG) neurons, substantially contributes to the upstroke of action potential in these neurons. Compelling evidence also revealed that the chemokine CCL2 plays a critical role in chronic pain facilitation via its binding to CCR2 receptors. In this study, we therefore investigated the effects of CCL2 on the density and kinetic properties of TTX-R Na(v)1.8 currents in acutely small/medium dissociated lumbar DRG neurons from naive adult rats. Whole-cell patch-clamp recordings demonstrated that CCL2 concentration-dependently increased TTX-resistant Na(v)1.8 current densities in both small- and medium-diameter sensory neurons. Incubation with CCL2 also shifted the activation and steady-state inactivation curves of Na(v)1.8 in a hyperpolarizing direction in small sensory neurons. No change in the activation and inactivation kinetics was, however, observed in medium-sized nociceptive neurons. Our electrophysiological recordings also demonstrated that the selective CCR2 antagonist INCB3344 [N-[2-[[(3S,4S)-1-E4-(1,3-benzodioxol-5-yl)-4-hydroxycyclohexyl]-4-ethoxy-3-pyrrolidinyl]amino]-2-oxoethyl]-3-(trifluoromethyl)benzamide] blocks the potentiation of Na(v)1.8 currents by CCL2 in a concentration-dependent manner. Furthermore, the enhancement in Na(v)1.8 currents was prevented by pretreatment with pertussis toxin (PTX) or gallein (a Gβγ inhibitor), indicating the involvement of Gβγ released from PTX-sensitive G(i/o)-proteins in the cross talk between CCR2 and Na(v)1.8. Together, our data clearly demonstrate that CCL2 may excite primary sensory neurons by acting on the biophysical properties of Na(v)1.8 currents

  7. [G-DRG: the for Germany modified AR-DRG system as a complete case-associated hospital reimbursement system according to section 17bKHG. Must it apply to psychiatry?].

    PubMed

    Fritze, J

    2001-06-01

    The introduction of a German ("German") DRG system (G-DRG) by 01.01.2003 is to improve efficiency and transparency of hospital performance and to terminate the presently implausible variability of costs. For the first time world wide the attempt is undertaken to finance by a DRG-system--supplemented by certain additional charges and rebates--hospital costs completely. Institutions submitted to the psychiatry personnel regulation (PsychPV) are excluded. As the basis for the G-DRG-system self-administration authorities have selected the Australian AR-DRG system. The adjustment to German conditions is an extraordinary challenge: Compatibility must be achieved between the German classification of diagnoses (CGD-10) and procedures (OPS-301) and pertinent coding standards and the Australian classification systems. In the hospitals a unit cost accounting must be established, which at least approximately allows a strictly case-related calculation of actual costs. The relative cost weights of the DRGS and thus in the long run, their prices will be calculated on the basis the costs of a complete sample of cases of a representative subset of hospitals. The full-scale DRG system will confront with new risks. One is the transfer of treatment components and thus costs to Institutions not covered by the DRG system (e.g. rehabilitation hospitals, psychiatry). Thus, psychiatry will be at least indirectly involved. In addition, psychiatric patients will be directly affected if they are treated--possibly due to misallocation--in non-psychiatric institutions (e.g. internal medicine, neurology) or in psychosomatic departments not covered by the PsychPV.

  8. Electrophysiological and morphological characteristics and synaptic connectivity of tyrosine hydroxylase-expressing neurons in adult mouse striatum.

    PubMed

    Ibáñez-Sandoval, Osvaldo; Tecuapetla, Fatuel; Unal, Bengi; Shah, Fulva; Koós, Tibor; Tepper, James M

    2010-05-19

    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 approximately 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 GABA(A) 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

  9. Fatty acid binding protein is induced in neurons of the dorsal root ganglia after peripheral nerve injury.

    PubMed

    De León, M; Welcher, A A; Nahin, R H; Liu, Y; Ruda, M A; Shooter, E M; Molina, C A

    1996-05-01

    Peripheral nerve trauma induces the expression of genes presumed to be involved in the process of nerve degeneration and repair. In the present study, an in vivo paradigm was employed to identify molecules which may have important roles in these processes. A cDNA library was constructed with RNA extracted from rat dorsal root ganglia (DRG) 3 days after a sciatic nerve crush. After differential hybridization to this library, several cDNAs were identified that encoded mRNAs that were upregulated in the DRG ipsilateral to the crush injury, as opposed to the contralateral or naive DRG. Approximately 0.15% of all the clones screened were found to be induced. This report presents the types of induced sequences identified and characterizes one of them, DA11. The 0.7 kb DA11 full length cDNA clone contains a 405 nucleotide open reading frame that encodes a putative protein of 15.2 kDa (135 amino acid residues) and is a member of the family of fatty acid binding proteins (FABP). The DA11 protein differs by one amino acid residue from the sequence of the C-FAPB protein and by eight residues from the sequence of mal1, proteins found in rat and mouse skin, respectively. Northern and Western blot analyses showed that the DA11 mRNA and protein were induced in the injured DRG. Furthermore, studies using antibodies generated against DA11 found that the DA11-like immunoreactivity was more pronounced in the nuclei of neurons located in the DRG ipsilateral to the sciatic cut than those located in the contralateral DRG. The induction of DA11 mRNA and protein in DRG neurons suggests, for the first time, the involvement of a neuronal FABP in the process of degeneration and repair in the nervous system.

  10. Comparative study of the distribution of the alpha-subunits of voltage-gated sodium channels in normal and axotomized rat dorsal root ganglion neurons.

    PubMed

    Fukuoka, Tetsuo; Kobayashi, Kimiko; Yamanaka, Hiroki; Obata, Koichi; Dai, Yi; Noguchi, Koichi

    2008-09-10

    We compared the distribution of the alpha-subunit mRNAs of voltage-gated sodium channels Nav1.1-1.3 and Nav1.6-1.9 and a related channel, Nax, in histochemically identified neuronal subpopulations of the rat dorsal root ganglia (DRG). In the naïve DRG, the expression of Nav1.1 and Nav1.6 was restricted to A-fiber neurons, and they were preferentially expressed by TrkC neurons, suggesting that proprioceptive neurons possess these channels. Nav1.7, -1.8, and -1.9 mRNAs were more abundant in C-fiber neurons compared with A-fiber ones. Nax was evenly expressed in both populations. Although Nav1.8 and -1.9 were preferentially expressed by TrkA neurons, other alpha-subunits were expressed independently of TrkA expression. Actually, all IB4(+) neurons expressed both Nav1.8 and -1.9, and relatively limited subpopulations of IB4(+) neurons (3% and 12%, respectively) expressed Nav1.1 and/or Nav1.6. These findings provide useful information in interpreting the electrophysiological characteristics of some neuronal subpopulations of naïve DRG. After L5 spinal nerve ligation, Nav1.3 mRNA was up-regulated mainly in A-fiber neurons in the ipsilateral L5 DRG. Although previous studies demonstrated that nerve growth factor (NGF) and glial cell-derived neurotrophic factor (GDNF) reversed this up-regulation, the Nav1.3 induction was independent of either TrkA or GFRalpha1 expression, suggesting that the induction of Nav1.3 may be one of the common responses of axotomized DRG neurons without a direct relationship to NGF/GDNF supply. PMID:18615542

  11. Substrate Availability of Mutant SPT Alters Neuronal Branching and Growth Cone Dynamics in Dorsal Root Ganglia

    PubMed Central

    Jun, Byung Kyu; Chandra, Ankush; Kuljis, Dika; Schmidt, Brian P.

    2015-01-01

    Serine palmitoyltransferase (SPT) is a key enzyme in the first step of sphingolipid biosynthesis. Mutations in the SPTLC1 gene that encodes for SPT subunits cause hereditary sensory neuropathy type 1. However, little is understood about how mutant SPT regulates mechanisms of sensory neuron and axonal growth. Using transgenic mice overexpressing the C133W SPT mutant, we found that mutant dorsal root ganglia (DRG) during growth in vitro exhibit increased neurite length and branching, coinciding with elevated expression of actin-cross-linking proteins at the neuronal growth cone, namely phosphorylated Ezrin/Radixin/Moesin. In addition, inhibition of SPT was able to reverse the mutant phenotype. Because mutant SPT preferentially uses l-alanine over its canonical substrate l-serine, we also investigated the effects of substrate availability on DRG neurons. Supplementation with l-serine or removal of l-alanine independently restored normal growth patterns in mutant SPTLC1C133W DRG. Therefore, we report that substrate availability and selectivity of SPT influence the regulation of neurite growth in DRG neurons. SIGNIFICANCE STATEMENT Hereditary sensory neuropathy type 1 is an autosomal-dominant disorder that leads to a sensory neuropathy due to mutations in the serine palmitoyltransferase (SPT) enzyme. We investigated how mutant SPT and substrate levels regulate neurite growth. Because SPT is an important enzyme in the synthesis of sphingolipids, our data are of broader significance to other peripheral and metabolic disorders. PMID:26446223

  12. 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

  13. Sleep is related to neuron numbers in the ventrolateral preoptic/intermediate nucleus in older adults with and without Alzheimer's disease.

    PubMed

    Lim, Andrew S P; Ellison, Brian A; Wang, Joshua L; Yu, Lei; Schneider, Julie A; Buchman, Aron S; Bennett, David A; Saper, Clifford B

    2014-10-01

    Fragmented sleep is a common and troubling symptom in ageing and Alzheimer's disease; however, its neurobiological basis in many patients is unknown. In rodents, lesions of the hypothalamic ventrolateral preoptic nucleus cause fragmented sleep. We previously proposed that the intermediate nucleus in the human hypothalamus, which has a similar location and neurotransmitter profile, is the homologue of the ventrolateral preoptic nucleus, but physiological data in humans were lacking. We hypothesized that if the intermediate nucleus is important for human sleep, then intermediate nucleus cell loss may contribute to fragmentation and loss of sleep in ageing and Alzheimer's disease. We studied 45 older adults (mean age at death 89.2 years; 71% female; 12 with Alzheimer's disease) from the Rush Memory and Aging Project, a community-based study of ageing and dementia, who had at least 1 week of wrist actigraphy proximate to death. Upon death a median of 15.5 months later, we used immunohistochemistry and stereology to quantify the number of galanin-immunoreactive intermediate nucleus neurons in each individual, and related this to ante-mortem sleep fragmentation. Individuals with Alzheimer's disease had fewer galaninergic intermediate nucleus neurons than those without (estimate -2872, standard error = 829, P = 0.001). Individuals with more galanin-immunoreactive intermediate nucleus neurons had less fragmented sleep, after adjusting for age and sex, and this association was strongest in those for whom the lag between actigraphy and death was <1 year (estimate -0.0013, standard error = 0.0005, P = 0.023). This association did not differ between individuals with and without Alzheimer's disease, and similar associations were not seen for two other cell populations near the intermediate nucleus. These data are consistent with the intermediate nucleus being the human homologue of the ventrolateral preoptic nucleus. Moreover, they demonstrate that a paucity of galanin

  14. Voltage-gated sodium channel function and expression in injured and uninjured rat dorsal root ganglia neurons.

    PubMed

    Yin, Ruoyuan; Liu, Dong; Chhoa, Mark; Li, Chi-Ming; Luo, Yi; Zhang, Maosheng; Lehto, Sonya G; Immke, David C; Moyer, Bryan D

    2016-01-01

    The nine members of the voltage-gated sodium channel (Nav) family mediate inward sodium currents that depolarize neurons and lead to action potential firing. Increased Nav expression and function in sensory ganglia may drive ectopic action potentials and result in neuropathic pain. Using patch-clamp electrophysiology and molecular biology techniques, experiments were performed to elucidate the contribution of Nav channels to sodium currents in rat dorsal root ganglion (DRG) neurons following the L5/L6 spinal nerve ligation (SNL) model of neuropathic pain. The abundance of DRG neurons with fast, tetrodotoxin sensitive (TTX-S) currents was seven-fold higher whereas the abundance of DRG neurons with slow, tetrodotoxin resistant (TTX-R) currents was nearly thirty-fold lower when comparing ipsilateral (injured) to contralateral (uninjured) neurons. TTX-S currents were elevated in larger neurons while TTX-R currents were reduced in both small and large neurons. Among Nav transcripts encoding TTX-R channels, Scn10a (Nav1.8) and Scn11a (Nav1.9) expression was twenty- to thirty-fold lower, while among Nav transcripts encoding TTX-S channels, Scn3a (Nav1.3) expression was four-fold higher in injured compared to uninjured DRG by qRT-PCR analysis. In summary, the SNL model of neuropathic pain induced a phenotypic switch in Nav expression from TTX-R to TTX-S channels in injured DRG neurons. Transcriptional reprogramming of Nav genes may drive ectopic action potential firing and contribute to neuropathic pain. PMID:25562420

  15. Voltage-gated sodium channel function and expression in injured and uninjured rat dorsal root ganglia neurons.

    PubMed

    Yin, Ruoyuan; Liu, Dong; Chhoa, Mark; Li, Chi-Ming; Luo, Yi; Zhang, Maosheng; Lehto, Sonya G; Immke, David C; Moyer, Bryan D

    2016-01-01

    The nine members of the voltage-gated sodium channel (Nav) family mediate inward sodium currents that depolarize neurons and lead to action potential firing. Increased Nav expression and function in sensory ganglia may drive ectopic action potentials and result in neuropathic pain. Using patch-clamp electrophysiology and molecular biology techniques, experiments were performed to elucidate the contribution of Nav channels to sodium currents in rat dorsal root ganglion (DRG) neurons following the L5/L6 spinal nerve ligation (SNL) model of neuropathic pain. The abundance of DRG neurons with fast, tetrodotoxin sensitive (TTX-S) currents was seven-fold higher whereas the abundance of DRG neurons with slow, tetrodotoxin resistant (TTX-R) currents was nearly thirty-fold lower when comparing ipsilateral (injured) to contralateral (uninjured) neurons. TTX-S currents were elevated in larger neurons while TTX-R currents were reduced in both small and large neurons. Among Nav transcripts encoding TTX-R channels, Scn10a (Nav1.8) and Scn11a (Nav1.9) expression was twenty- to thirty-fold lower, while among Nav transcripts encoding TTX-S channels, Scn3a (Nav1.3) expression was four-fold higher in injured compared to uninjured DRG by qRT-PCR analysis. In summary, the SNL model of neuropathic pain induced a phenotypic switch in Nav expression from TTX-R to TTX-S channels in injured DRG neurons. Transcriptional reprogramming of Nav genes may drive ectopic action potential firing and contribute to neuropathic pain.

  16. Depression of Ca2+/Calmodulin-Dependent Protein Kinase II in Dorsal Root Ganglion Neurons after Spinal Nerve Ligation

    PubMed Central

    Kojundzic, Sanja Lovric; Puljak, Livia; Hogan, Quinn; Sapunar, Damir

    2014-01-01

    The enzyme calcium/calmodulin-dependent protein kinase II (CaMKII) is associated with memory and its α isoform is critical for development of activity-induced synaptic changes. Therefore, we hypothesized that CaMKII is involved in altered function of dorsal root ganglion (DRG) neurons after neuronal injury. To test this hypothesis, Sprague–Dawley rats were made hyperalgesic by L5 and L6 spinal nerve ligation (SNL), and changes in total phosphorylated and unphosphorylated CaMKII (tCaMKII) and phosphorylated form of its α isoform (pCaMKIIα) were analyzed using immunochemistry in different subpopulations of DRG. SNL did not induce any changes in tCaMKII between experimental groups, while the overall percentage of pCaMKIIα-positive neurons in injured L5 DRG SNL (24.8%) decreased significantly when compared to control (41.7%). SNL did not change the percentage of pCaMKIIα/N52 colabeled neurons but decreased the percentage of N52-negative nonmyelinated neurons that expressed pCaMKIIα from 27% in control animals to 11% after axotomy. We also observed a significant decrease in the percentage of small nonpeptidergic neurons labeled with IB4 (37.6% in control vs. 4.0% in L5 SNL DRG), as well as a decrease in the percentage of pCaMKIIα/IB4 colabeled neurons in injured L5 DRGs (27% in control vs. 1% in L5 DRG of SNL group). Our results show that reduction in pCaMKIIα levels following peripheral injury is due to the loss of IB4-positive neurons. These results indicate that diminished afferent activity after axotomy may lead to decreased phosphorylation of CaMKIIα. PMID:19882720

  17. Genome-wide analysis of the bHLH gene family in planarians identifies factors required for adult neurogenesis and neuronal regeneration.

    PubMed

    Cowles, Martis W; Brown, David D R; Nisperos, Sean V; Stanley, Brianna N; Pearson, Bret J; Zayas, Ricardo M

    2013-12-01

    In contrast to most well-studied model organisms, planarians have a remarkable ability to completely regenerate a functional nervous system from a pluripotent stem cell population. Thus, planarians provide a powerful model to identify genes required for adult neurogenesis in vivo. We analyzed the basic helix-loop-helix (bHLH) family of transcription factors, many of which are crucial for nervous system development and have been implicated in human diseases. However, their potential roles in adult neurogenesis or central nervous system (CNS) function are not well understood. We identified 44 planarian bHLH homologs, determined their patterns of expression in the animal and assessed their functions using RNAi. We found nine bHLHs expressed in stem cells and neurons that are required for CNS regeneration. Our analyses revealed that homologs of coe, hes (hesl-3) and sim label progenitors in intact planarians, and following amputation we observed an enrichment of coe(+) and sim(+) progenitors near the wound site. RNAi knockdown