A role for Runx transcription factor signaling in dorsal root ganglion sensory neuron diversification.

PubMed

Kramer, Ina; Sigrist, Markus; de Nooij, Joriene C; Taniuchi, Ichiro; Jessell, Thomas M; Arber, Silvia

2006-02-02

Subpopulations of sensory neurons in the dorsal root ganglion (DRG) can be characterized on the basis of sensory modalities that convey distinct peripheral stimuli, but the molecular mechanisms that underlie sensory neuronal diversification remain unclear. Here, we have used genetic manipulations in the mouse embryo to examine how Runx transcription factor signaling controls the acquisition of distinct DRG neuronal subtype identities. Runx3 acts to diversify an Ngn1-independent neuronal cohort by promoting the differentiation of proprioceptive sensory neurons through erosion of TrkB expression in prospective TrkC+ sensory neurons. In contrast, Runx1 controls neuronal diversification within Ngn1-dependent TrkA+ neurons by repression of neuropeptide CGRP expression and controlling the fine pattern of laminar termination in the dorsal spinal cord. Together, our findings suggest that Runx transcription factor signaling plays a key role in sensory neuron diversification.

Bortezomib alters microtubule polymerization and axonal transport in rat dorsal root ganglion neurons

PubMed Central

Staff, Nathan P.; Podratz, Jewel L.; Grassner, Lukas; Bader, Miranda; Paz, Justin; Knight, Andrew M.; Loprinzi, Charles L.; Trushina, Eugenia; Windebank, Anthony J.

2013-01-01

Bortezomib is part of a newer class of chemotherapeutic agents whose mechanism of action is inhibition of the proteasome-ubiquitination system. Primarily used in multiple myeloma, bortezomib causes a sensory-predominant axonal peripheral neuropathy in approximately 30% of patients. There are no established useful preventative agents for bortezomib-induced peripheral neuropathy (BIPN), and the molecular mechanisms of BIPN are unknown. We have developed an in vitro model of BIPN using rat dorsal root ganglia neuronal cultures. At clinically–relevant dosages, bortezomib produces a sensory axonopathy as evidenced by whole explant outgrowth and cell survival assays. This sensory axonopathy is associated with alterations in tubulin and results in accumulation of somatic tubulin without changes in microtubule ultrastructure. Furthermore, we observed an increased proportion of polymerized tubulin, but not total or acetylated tubulin, in bortezomib-treated DRG neurons. Similar findings are observed with lactacystin, an unrelated proteasome-inhibitor, which argues for a class effect of proteasome inhibition on dorsal root ganglion neurons. Finally, there is a change in axonal transport of mitochondria induced by bortezomib in a time-dependent fashion. In summary, we have developed an in vitro model of BIPN that recapitulates the clinical sensory axonopathy; this model demonstrates that bortezomib induces an alteration in microtubules and axonal transport. This robust model will be used in future mechanistic studies of BIPN and its prevention. PMID:24035926

Painful Pathways Induced by Toll-like Receptor Stimulation of Dorsal Root Ganglion Neurons

PubMed Central

Qi, Jia; Buzas, Krisztina; Fan, Huiting; Cohen, Jeffrey I.; Wang, Kening; Mont, Erik; Klinman, Dennis; Oppenheim, Joost J.; Howard, O.M. Zack

2011-01-01

We hypothesize that innate immune signals from infectious organisms and/or injured tissues may activate peripheral neuronal pain signals. In this study, we demonstrated that toll-like receptors 3/7/9 (TLRs) are expressed by human dorsal root ganglion neurons (DRGNs) and in cultures of primary mouse DRGNs. Stimulation of murine DRGNs with TLR ligands induced expression and production of proinflammatory chemokines and cytokines CCL5 (RANTES), CXCL10 (IP10), interleukin-1alpha, interleukin-1beta, and prostaglandin E2 (PGE2), which have previously been shown to augment pain. Further, TLR ligands up-regulated the expression of a nociceptive receptor transient receptor potential vanilloid type 1 (TRPV1), and enhanced calcium flux by TRPV1 expressing DRGNs. Using a tumor-induced temperature sensitivity model, we showed that in vivo administration of a TLR9 antagonist, known as a suppressive ODN, blocked tumor-induced temperature sensitivity. Taken together, these data indicate that stimulation of peripheral neurons by TLR ligands can induce nerve pain. PMID:21515789

PKA-induced internalization of slack KNa channels produces dorsal root ganglion neuron hyperexcitability.

PubMed

Nuwer, Megan O; Picchione, Kelly E; Bhattacharjee, Arin

2010-10-20

Inflammatory mediators through the activation of the protein kinase A (PKA) pathway sensitize primary afferent nociceptors to mechanical, thermal, and osmotic stimuli. However, it is unclear which ion conductances are responsible for PKA-induced nociceptor hyperexcitability. We have previously shown the abundant expression of Slack sodium-activated potassium (K(Na)) channels in nociceptive dorsal root ganglion (DRG) neurons. Here we show using cultured DRG neurons, that of the total potassium current, I(K), the K(Na) current is predominantly inhibited by PKA. We demonstrate that PKA modulation of K(Na) channels does not happen at the level of channel gating but arises from the internal trafficking of Slack channels from DRG membranes. Furthermore, we found that knocking down the Slack subunit by RNA interference causes a loss of firing accommodation analogous to that observed during PKA activation. Our data suggest that the change in nociceptive firing occurring during inflammation is the result of PKA-induced Slack channel trafficking.

Comparative anatomy of the accessory ciliary ganglion in mammals.

PubMed

Kuchiiwa, S; Kuchiiwa, T; Suzuki, T

1989-01-01

The orbits of 13 mammalian species (pig, sika deer, domestic sheep, horse, cat, fox, racoon dog, marten, rat, rabbit, crab-eating macaque, japanese macaque and man) were stained with silver nitrate and dissected under a dissecting microscope with special attention to the presence and location of the accessory ciliary ganglion. Some preparations were stained with thionin and examined as whole-mounts in a transmission microscope. The accessory ciliary ganglion was present in all 13 species, although the number and degree of development varied greatly from species to species. The accessory ciliary ganglion could be readily differentiated from the main ciliary ganglion in the following respects: it was located on the short ciliary nerve, and it had no root derived directly from the inferior trunk of the oculomotor nerve and it never attaches to this nerve. In many species, ganglion cells were also scattered in the short ciliary nerves in the stained whole preparations. In a few species, there were one or more small ganglia on the nerve to the inferior oblique muscle.

Redox modulation of A-type K+ currents in pain-sensing dorsal root ganglion neurons.

PubMed

Hsieh, Chi-Pan

2008-06-06

Redox modulation of fast inactivation has been described in certain cloned A-type voltage-gated K(+) (Kv) channels in expressing systems, but the effects remain to be demonstrated in native neurons. In this study, we examined the effects of cysteine-specific redox agents on the A-type K(+) currents in acutely dissociated small diameter dorsal root ganglion (DRG) neurons from rats. The fast inactivation of most A-type currents was markedly removed or slowed by the oxidizing agents 2,2'-dithio-bis(5-nitropyridine) (DTBNP) and chloramine-T. Dithiothreitol, a reducing agent for the disulfide bond, restored the inactivation. These results demonstrated that native A-type K(+) channels, probably Kv1.4, could switch the roles between inactivating and non-inactivating K(+) channels via redox regulation in pain-sensing DRG neurons. The A-type channels may play a role in adjusting pain sensitivity in response to peripheral redox conditions.

PKC regulates capsaicin-induced currents of dorsal root ganglion neurons in rats.

PubMed

Zhou, Y; Zhou, Z S; Zhao, Z Q

2001-10-01

Capsaicin activates a non-specific cation conductance in a subset of dorsal root ganglion (DRG) neurons. The inward current and membrane potential of acutely isolated DRG neurons were examined using whole-cell patch recording methods. We report here that the current and voltage responses activated by capsaicin were markedly increased by phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC). The mean current, after application of 0.3 microM PMA, was 153.5+/-5.7% of control (n=32) in Ca(2+)-free external solution and 181.6+/-6.8% of control (n=15) in standard external solution. Under current-clamp conditions, 0.3 microM PMA facilitated capsaicin-induced depolarization and action potential generation. Bindolylmaleimide I (BIM), a specific inhibitor of PKC activity, abolished the effect of PMA. In addition, capsaicin-evoked current was attenuated to 68.3+/-5.0% of control (n=13) by individual administration of 1 microM BIM in standard external solution, while 0.3 microM BIM did not have this effect. These data suggest that PKC can directly regulate the capsaicin response in DRG neurons, which could increase nociceptive sensory transmission and contribute to hyperalgesia.

Multiunit Activity-Based Real-Time Limb-State Estimation from Dorsal Root Ganglion Recordings

PubMed Central

Han, Sungmin; Chu, Jun-Uk; Kim, Hyungmin; Park, Jong Woong; Youn, Inchan

2017-01-01

Proprioceptive afferent activities could be useful for providing sensory feedback signals for closed-loop control during functional electrical stimulation (FES). However, most previous studies have used the single-unit activity of individual neurons to extract sensory information from proprioceptive afferents. This study proposes a new decoding method to estimate ankle and knee joint angles using multiunit activity data. Proprioceptive afferent signals were recorded from a dorsal root ganglion with a single-shank microelectrode during passive movements of the ankle and knee joints, and joint angles were measured as kinematic data. The mean absolute value (MAV) was extracted from the multiunit activity data, and a dynamically driven recurrent neural network (DDRNN) was used to estimate ankle and knee joint angles. The multiunit activity-based MAV feature was sufficiently informative to estimate limb states, and the DDRNN showed a better decoding performance than conventional linear estimators. In addition, processing time delay satisfied real-time constraints. These results demonstrated that the proposed method could be applicable for providing real-time sensory feedback signals in closed-loop FES systems. PMID:28276474

Electrical stimulation at the dorsal root ganglion preserves trabecular bone mass and microarchitecture of the tibia in hindlimb-unloaded rats.

PubMed

Lau, Y-C; Qian, X; Po, K-T; Li, L-M; Guo, X

2015-02-01

This study seeks to investigate the effect of electrical stimulation (ES) at dorsal root ganglion (DRG) on disuse bone loss in a rat model. Hindlimb unloading for 14 days resulted in significant bone loss in rat tibia while rats with ES at DRG showed a significant reduced bone loss Mechanical unloading induces osteoporosis in both human and animals. Previous studies demonstrated that electrical stimulation (ES) to dorsal root ganglion (DRG) could trigger secretion of calcitonin gene-related peptide (CGRP) which plays an important role in bone modeling and remodeling. This study seeks to investigate the effect of ES to DRG on disuse bone loss in a rat model. Twenty-four rats were randomly assigned in three experimental groups: cage control (CC), hindlimb unloading (HU), and hindlimb unloading with ES (HUES). ES was applied via implantable micro-electrical stimulators (IMES) to right DRGs at vertebral levels L4-L6 in HUES group. Hindlimb unloading for 14 days resulted in 25.9% decrease in total bone mineral content (BMC), 29.2% decrease in trabecular BMD and trabecular microarchitecture and connectivity were significantly deteriorated in the proximal tibia metaphysis in HU group, while rats with ES at DRG showed significant reduced bone loss that there was 3.8% increase in total BMC, 2.3% decrease in trabecular BMD, and significant improvement in trabecular microarchitecture. There was a concurrent enhancement of expression of CGRP in stimulated DRGs. The results confirm the effect of ES at DRG on enhancing CGRP expression and suggest potential applications of IMES for the prevention and treatment of disuse bone loss.

Single cell RNA sequencing of stem cell-derived retinal ganglion cells.

PubMed

Daniszewski, Maciej; Senabouth, Anne; Nguyen, Quan H; Crombie, Duncan E; Lukowski, Samuel W; Kulkarni, Tejal; Sluch, Valentin M; Jabbari, Jafar S; Chamling, Xitiz; Zack, Donald J; Pébay, Alice; Powell, Joseph E; Hewitt, Alex W

2018-02-13

We used single cell sequencing technology to characterize the transcriptomes of 1,174 human embryonic stem cell-derived retinal ganglion cells (RGCs) at the single cell level. The human embryonic stem cell line BRN3B-mCherry (A81-H7), was differentiated to RGCs using a guided differentiation approach. Cells were harvested at day 36 and prepared for single cell RNA sequencing. Our data indicates the presence of three distinct subpopulations of cells, with various degrees of maturity. One cluster of 288 cells showed increased expression of genes involved in axon guidance together with semaphorin interactions, cell-extracellular matrix interactions and ECM proteoglycans, suggestive of a more mature RGC phenotype.

Ganglion Cysts

MedlinePlus

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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.

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

Wogonin prevents rat dorsal root ganglion neurons death via inhibiting tunicamycin-induced ER stress in vitro.

PubMed

Xu, Shujuan; Zhao, Xin; Zhao, Quanlai; Zheng, Quan; Fang, Zhen; Yang, Xiaoming; Wang, Hong; Liu, Ping; Xu, Hongguang

2015-04-01

Wogonin is a natural flavonoid isolated from the root of Scutellaria baicalensis Georgi, which has been widely used in various research areas for its anti-oxidant, anti-inflammatory, and anti-cancer activities. It also presents a neuroprotective effect in the brain while encounters stress conditions, but the mechanisms controlling the neuroprotective effect of wogonin are not clear. In this study, we investigated the biomechanism underlying the neuroprotective effect of wogonin on rat dorsal root ganglion (DRG) neurons. Wogonin pre-treatment at 75 μM significantly increased the cell viability of DRG neurons and decreased the number of the propidium iodide-positive DRG neurons before the endoplasmic reticulum (ER) stress is being induced by tunicamycin (TUN) (0.75 μg/mL). In addition, Wogonin also inhibited the release of LDH and up-regulated the level of GSH. Furthermore, wogonin decreased the activation of ER stress-related molecules, including glucose-regulated protein 78 (GRP78), GRP94, C/EBP-homologous protein, active caspase12 and active caspase3, phosphorylation of pancreatic ER stress kinase, and eukaryotic initiation factor 2 alpha (eIF2α). In summary, our results indicated that wogonin could protect DRG neurons against TUN-induced ER stress.

Deficiency of Suppressor Enhancer Lin12 1 Like (SEL1L) in Mice Leads to Systemic Endoplasmic Reticulum Stress and Embryonic Lethality*

PubMed Central

Francisco, Adam B.; Singh, Rajni; Li, Shuai; Vani, Anish K.; Yang, Liu; Munroe, Robert J.; Diaferia, Giuseppe; Cardano, Marina; Biunno, Ida; Qi, Ling; Schimenti, John C.; Long, Qiaoming

2010-01-01

Stress in the endoplasmic reticulum (ER) plays an important causal role in the pathogenesis of several chronic diseases such as Alzheimer, Parkinson, and diabetes mellitus. Insight into the genetic determinants responsible for ER homeostasis will greatly facilitate the development of therapeutic strategies for the treatment of these debilitating diseases. Suppressor enhancer Lin12 1 like (SEL1L) is an ER membrane protein and was thought to be involved in the quality control of secreted proteins. Here we show that the mice homozygous mutant for SEL1L were embryonic lethal. Electron microscopy studies revealed a severely dilated ER in the fetal liver of mutant embryos, indicative of alteration in ER homeostasis. Consistent with this, several ER stress responsive genes were significantly up-regulated in the mutant embryos. Mouse embryonic fibroblast cells deficient in SEL1L exhibited activated unfolded protein response at the basal state, impaired ER-associated protein degradation, and reduced protein secretion. Furthermore, markedly increased apoptosis was observed in the forebrain and dorsal root ganglions of mutant embryos. Taken together, our results demonstrate an essential role for SEL1L in protein quality control during mouse embryonic development. PMID:20197277

Deficiency of suppressor enhancer Lin12 1 like (SEL1L) in mice leads to systemic endoplasmic reticulum stress and embryonic lethality.

PubMed

Francisco, Adam B; Singh, Rajni; Li, Shuai; Vani, Anish K; Yang, Liu; Munroe, Robert J; Diaferia, Giuseppe; Cardano, Marina; Biunno, Ida; Qi, Ling; Schimenti, John C; Long, Qiaoming

2010-04-30

Stress in the endoplasmic reticulum (ER) plays an important causal role in the pathogenesis of several chronic diseases such as Alzheimer, Parkinson, and diabetes mellitus. Insight into the genetic determinants responsible for ER homeostasis will greatly facilitate the development of therapeutic strategies for the treatment of these debilitating diseases. Suppressor enhancer Lin12 1 like (SEL1L) is an ER membrane protein and was thought to be involved in the quality control of secreted proteins. Here we show that the mice homozygous mutant for SEL1L were embryonic lethal. Electron microscopy studies revealed a severely dilated ER in the fetal liver of mutant embryos, indicative of alteration in ER homeostasis. Consistent with this, several ER stress responsive genes were significantly up-regulated in the mutant embryos. Mouse embryonic fibroblast cells deficient in SEL1L exhibited activated unfolded protein response at the basal state, impaired ER-associated protein degradation, and reduced protein secretion. Furthermore, markedly increased apoptosis was observed in the forebrain and dorsal root ganglions of mutant embryos. Taken together, our results demonstrate an essential role for SEL1L in protein quality control during mouse embryonic development.

Millisecond infrared laser pulses depolarize and elicit action potentials on in-vitro dorsal root ganglion neurons

PubMed Central

Paris, Lambert; Marc, Isabelle; Charlot, Benoit; Dumas, Michel; Valmier, Jean; Bardin, Fabrice

2017-01-01

This work focuses on the optical stimulation of dorsal root ganglion (DRG) neurons through infrared laser light stimulation. We show that a few millisecond laser pulse at 1875 nm induces a membrane depolarization, which was observed by the patch-clamp technique. This stimulation led to action potentials firing on a minority of neurons beyond an energy threshold. A depolarization without action potential was observed for the majority of DRG neurons, even beyond the action potential energy threshold. The use of ruthenium red, a thermal channel blocker, stops the action potential generation, but has no effects on membrane depolarization. Local temperature measurements reveal that the depolarization amplitude is sensitive to the amplitude of the temperature rise as well as to the time rate of change of temperature, but in a way which may not fully follow a photothermal capacitive mechanism, suggesting that more complex mechanisms are involved. PMID:29082085

RNA interference-based functional knockdown of the voltage-gated potassium channel Kv7.2 in dorsal root ganglion neurons after in vitro and in vivo gene transfer by adeno-associated virus vectors.

PubMed

Valdor, Markus; Wagner, Anke; Röhrs, Viola; Berg, Johanna; Fechner, Henry; Schröder, Wolfgang; Tzschentke, Thomas M; Bahrenberg, Gregor; Christoph, Thomas; Kurreck, Jens

2018-01-01

Activation of the neuronal potassium channel Kv7.2 encoded by the KCNQ2 gene has recently been shown to be an attractive mechanism to inhibit nociceptive transmission. However, potent, selective, and clinically proven activators of Kv7.2/Kv7.3 currents with analgesic properties are still lacking. An important prerequisite for the development of new drugs is a model to test the selectivity of novel agonists by abrogating Kv7.2/Kv7.3 function. Since constitutive knockout mice are not viable, we developed a model based on RNA interference-mediated silencing of KCNQ2. By delivery of a KCNQ2-specific short hairpin RNA with adeno-associated virus vectors, we completely abolished the activity of the specific Kv7.2/Kv7.3-opener ICA-27243 in rat sensory neurons. Results obtained in the silencing experiments were consistent between freshly prepared and cryopreserved dorsal root ganglion neurons, as well as in dorsal root ganglion neurons dissociated and cultured after in vivo administration of the silencing vector by intrathecal injections into rats. Interestingly, the tested associated virus serotypes substantially differed with respect to their transduction capability in cultured neuronal cell lines and primary dorsal root ganglion neurons and the in vivo transfer of transgenes by intrathecal injection of associated virus vectors. However, our study provides the proof-of-concept that RNA interference-mediated silencing of KCNQ2 is a suitable approach to create an ex vivo model for testing the specificity of novel Kv7.2/Kv7.3 agonists.

A high-threshold heat-activated channel in cultured rat dorsal root ganglion neurons resembles TRPV2 and is blocked by gadolinium.

PubMed

Leffler, Andreas; Linte, Ramona Madalina; Nau, Carla; Reeh, Peter; Babes, Alexandru

2007-07-01

Heat-activated ion channels from the vanilloid-type TRP group (TRPV1-4) seem to be central for heat-sensitivity of nociceptive sensory neurons. Displaying a high-threshold (> 52 degrees C) for activation, TRPV2 was proposed to act as a sensor for intense noxious heat in mammalian sensory neurons. However, although TRPV2 is expressed in a distinct population of thinly myelinated primary afferents, a widespread expression in a variety of neuronal and non-neuronal tissues suggests a more diverse physiological role of TRPV2. In its role as a heat-sensor, TRPV2 has not been thoroughly characterized in terms of biophysical and pharmacological properties. In the present study, we demonstrate that the features of heterologously expressed rat TRPV2 closely resemble those of high-threshold heat-evoked currents in medium- and large-sized capsaicin-insensitive rat dorsal root ganglion (DRG) neurons. Both in TRPV2-expressing human embryonic kidney (HEK)293t cells and in DRGs, high-threshold heat-currents were sensitized by repeated activation and by the TRPV1-3 agonist, 2-aminoethoxydiphenyl borate (2-APB). In addition to a previously described block by ruthenium red, we identified the trivalent cations, lanthanum (La(3+)) and gadolinium (Gd(3+)) as potent blockers of TRPV2. Thus, we present a new pharmacological tool to distinguish between heat responses of TRPV2 and the closely related capsaicin-receptor, TRPV1, which is strongly sensitized by trivalent cations. We demonstrate that self-sensitization of heat-evoked currents through TRPV2 does not require extracellular calcium and that TRPV2 can be activated in cell-free membrane patches in the outside-out configuration. Taken together our results provide new evidence for a role of TRPV2 in mediating high-threshold heat responses in a subpopulation of mammalian sensory neurons.

Spontaneous Discharge Patterns in Cochlear Spiral Ganglion Cells Prior to the Onset of Hearing in Cats

PubMed Central

Jones, Timothy A.; Leake, Patricia A.; Snyder, Russell L.; Stakhovskaya, Olga; Bonham, Ben

2008-01-01

Spontaneous neural activity has been recorded in the auditory nerve of cats as early as 2 days postnatal (P2 ), yet individual auditory neurons do not respond to ambient sound levels below 90–100 dB SPL until about P10. Significant refinement of the central projections from the spiral ganglion to the cochlear nucleus occurs during this neonatal period. This refinement may be dependent on peripheral spontaneous discharge activity. We recorded from single spiral ganglion cells in kittens aged P3 to P9. The spiral ganglion was accessed via the round window through the spiral lamina. A total of 112 ganglion cells were isolated for study in 9 animals. Spike rates in neonates were very low, ranging from 0.06 to 56 sp/s with a mean of 3.09 +/− 8.24 sp/s. Ganglion cells in neonatal kittens exhibited remarkable repetitive spontaneous bursting discharge patterns. The unusual patterns were evident in the large mean interval coefficient of variation (CVi = 2.9 +/−1.6) and burst index of 5.2 +/− 3.5 across ganglion cells. Spontaneous bursting patterns in these neonatal mammals were similar to those reported for cochlear ganglion cells of the embryonic chicken suggesting this may be a general phenomenon that is common across animal classes. Rhythmic spontaneous discharge of retinal ganglion cells has been shown to be important in the development of central retinotopic projections and normal binocular vision (Shatz, 1996, Proc Natl Acad Sci 93). Bursting rhythms in cochlear ganglion cells may play a similar role in the auditory system during pre-hearing periods. PMID:17686914

Effects of nano red elemental selenium on sodium currents in rat dorsal root ganglion neurons.

PubMed

Yuan, Huijun; Lin, Jiarui; Lan, Tonghan

2006-01-01

Nano red elemental selenium (Nano-Se), was demonstrated to be useful in medical and scientific researches. Here, we investigated the effects of Nano-Se on sodium currents on rat dorsal root ganglion neurons (DRG), using the whole-cell patch clamp method. Nano-Se reversibly decrease the I(Na)(TTX-S) in a concentration-dependent, time-dependent and open-channel block manners without affecting I(Na)(TTX-R). It shifted the steady-state activation and inactivation curves for I(Na) to more negative potentials. In the research of recovery from inactivation, the recovery time constant is longer in the present of Nano-Se. Nano-Se had a weaker inhibitory effect on I(Na), compared with marked decrease caused by selenite which indicated that Nano-Se is less neurotoxic than selenite in short-term/large dose treatments and had similar bio availability to sodium selenite. The results of interaction between the effects of Nano-Se and selenite on sodium currents indicated a negative allosteric interaction between the selenite binding site and the Nano-Se binding site or that they have the same competitive binding site.

Transcriptomic and anatomical complexity of primary, seminal, and crown roots highlight root type-specific functional diversity in maize (Zea mays L.)

PubMed Central

Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank

2016-01-01

Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. PMID:26628518

Characterization of peripheral and central sensitization after dorsal root ganglion intervention in patients with unilateral lumbosacral radicular pain: a prospective pilot study.

PubMed

Mehta, V; Snidvongs, S; Ghai, B; Langford, R; Wodehouse, T

2017-06-01

Quantitative sensory testing (QST) has been used to predict the outcome of epidural steroid injections in lumbosacral radicular pain and has the potential to be an important tool in the selection of appropriate treatment (such as epidural steroid injections vs surgery) for patients with chronic radicular pain. In addition, QST assists in identification of the pain pathways of peripheral and central sensitization in selected groups of patients. Twenty-three patients were given dorsal root ganglion (DRG) infiltration with local anaesthesia and steroid ('DRG block'), and those who demonstrated at least 50% pain relief were offered pulsed radiofrequency (PRF) to the DRG. Questionnaires and QST scores were measured before the DRG blocks and at 1 week and 3 months after their procedure. Those who received PRF also answered questionnaires and underwent QST measurements at 1 week and 3 months after their procedure. There was a significant increase in pressure pain threshold scores after DRG blocks. A reduced conditioned pain modulation response was seen before DRG, which increased after the procedure. Ten out of 23 patients underwent PRF to the DRG, and an increase in pressure pain threshold scores after PRF was observed. The conditioned pain modulation response was maintained in this group and increased after PRF. The study demonstrates that patients with unilateral radicular low back pain who receive dorsal root ganglion interventions show changes in pressure pain thresholds and conditioned pain modulation that are consistent with a 'normalization' of peripheral and central sensitization. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Transcriptomic and anatomical complexity of primary, seminal, and crown roots highlight root type-specific functional diversity in maize (Zea mays L.).

PubMed

Tai, Huanhuan; Lu, Xin; Opitz, Nina; Marcon, Caroline; Paschold, Anja; Lithio, Andrew; Nettleton, Dan; Hochholdinger, Frank

2016-02-01

Maize develops a complex root system composed of embryonic and post-embryonic roots. Spatio-temporal differences in the formation of these root types imply specific functions during maize development. A comparative transcriptomic study of embryonic primary and seminal, and post-embryonic crown roots of the maize inbred line B73 by RNA sequencing along with anatomical studies were conducted early in development. Seminal roots displayed unique anatomical features, whereas the organization of primary and crown roots was similar. For instance, seminal roots displayed fewer cortical cell files and their stele contained more meta-xylem vessels. Global expression profiling revealed diverse patterns of gene activity across all root types and highlighted the unique transcriptome of seminal roots. While functions in cell remodeling and cell wall formation were prominent in primary and crown roots, stress-related genes and transcriptional regulators were over-represented in seminal roots, suggesting functional specialization of the different root types. Dynamic expression of lignin biosynthesis genes and histochemical staining suggested diversification of cell wall lignification among the three root types. Our findings highlight a cost-efficient anatomical structure and a unique expression profile of seminal roots of the maize inbred line B73 different from primary and crown roots. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Tibial periosteal ganglion cyst: The ganglion in disguise.

PubMed

Reghunath, Anjuna; Mittal, Mahesh K; Khanna, Geetika; Anil, V

2017-01-01

Soft tissue ganglions are commonly encountered cystic lesions around the wrist presumed to arise from myxomatous degeneration of periarticular connective tissue. Lesions with similar pathology in subchondral location close to joints, and often simulating a geode, is the less common entity called intraosseous ganglion. Rarer still is a lesion produced by mucoid degeneration and cyst formation of the periostium of long bones, rightly called the periosteal ganglion. They are mostly found in the lower extremities at the region of pes anserinus, typically limited to the periosteum and outer cortex without any intramedullary component. We report the case of a 62 year-old male who presented with a tender swelling on the mid shaft of the left tibia, which radiologically suggested a juxtacortical lesion extending to the soft tissue or a soft tissue neoplasm eroding the bony cortex of tibia. It was later diagnosed definitively as a periosteal ganglion in an atypical location, on further radiologic work-up and histopathological correlation.

Tibial periosteal ganglion cyst: The ganglion in disguise

PubMed Central

Reghunath, Anjuna; Mittal, Mahesh K; Khanna, Geetika; Anil, V

2017-01-01

Soft tissue ganglions are commonly encountered cystic lesions around the wrist presumed to arise from myxomatous degeneration of periarticular connective tissue. Lesions with similar pathology in subchondral location close to joints, and often simulating a geode, is the less common entity called intraosseous ganglion. Rarer still is a lesion produced by mucoid degeneration and cyst formation of the periostium of long bones, rightly called the periosteal ganglion. They are mostly found in the lower extremities at the region of pes anserinus, typically limited to the periosteum and outer cortex without any intramedullary component. We report the case of a 62 year-old male who presented with a tender swelling on the mid shaft of the left tibia, which radiologically suggested a juxtacortical lesion extending to the soft tissue or a soft tissue neoplasm eroding the bony cortex of tibia. It was later diagnosed definitively as a periosteal ganglion in an atypical location, on further radiologic work-up and histopathological correlation. PMID:28515597

Redox Changes During the Cell Cycle in the Embryonic Root Meristem of Arabidopsis thaliana.

PubMed

de Simone, Ambra; Hubbard, Rachel; de la Torre, Natanael Viñegra; Velappan, Yazhini; Wilson, Michael; Considine, Michael J; Soppe, Wim J J; Foyer, Christine H

2017-12-20

The aim of this study was to characterize redox changes in the nuclei and cytosol occurring during the mitotic cell cycle in the embryonic roots of germinating Arabidopsis seedlings, and to determine how redox cycling was modified in mutants with a decreased capacity for ascorbate synthesis. Using an in vivo reduction-oxidation (redox) reporter (roGFP2), we show that transient oxidation of the cytosol and the nuclei occurred at G1 in the synchronized dividing cells of the Arabidopsis root apical meristem, with reduction at G2 and mitosis. This redox cycle was absent from low ascorbate mutants in which nuclei were significantly more oxidized than controls. The cell cycle-dependent increase in nuclear size was impaired in the ascorbate-deficient mutants, which had fewer cells per unit area in the root proliferation zone. The transcript profile of the dry seeds and size of the imbibed seeds was strongly influenced by low ascorbate but germination, dormancy release and seed aging characteristics were unaffected. These data demonstrate the presence of a redox cycle within the plant cell cycle and that the redox state of the nuclei is an important factor in cell cycle progression. Controlled oxidation is a key feature of the early stages of the plant cell cycle. However, sustained mild oxidation restricts nuclear functions and impairs progression through the cell cycle leading to fewer cells in the root apical meristem. Antioxid. Redox Signal. 27, 1505-1519.

Effects of male and female sex steroids on the development of normal and the transient Froriep's dorsal root ganglia of the chick embryo.

PubMed

Liu, Jiali; Chen, Dawei; Goldstein, Ronald S; Cui, Sheng

2005-03-22

Sex steroids can influence developmental processes and support the survival of neurons in the embryonic central nervous system. Recent studies have shown that estrogen receptors are also expressed in the peripheral nervous system, in the dorsal root ganglia (DRG) of chick embryos. However, no studies have examined the effects of sex steroids on development of embryonic DRG. In the present study, 0.2 microg, 1.0 microg, 5.0 microg 10 microg, 20 microg, 25 microg, and 40 microg doses of testosterone or estradiol were delivered to chick embryos at Hamburger and Hamilton stage 18 (E3). The actions of these doses of sex steroids on the development of the C5DRG (fifth cervical ganglion, a "normal" DRG) and C2DRG (a transient ganglion known as a "Froriep's DRG") were then evaluated by quantifying ganglionic volumes, cell number, proliferation, and apoptosis after 1 day of growth to stage 23. We found that both testosterone and estradiol promoted proliferation of cells in both normal DRG and the Froriep's ganglia. By contrast, estradiol significantly increased the number of apoptotic cells, while testosterone strongly inhibited apoptosis. These actions of sex steroids on DRG development were dose-dependent, and C5DRG and C2DRG showed different sensitivities to the applied sex steroids. In addition, the present results demonstrated that specific ER and AR inhibitors (tamoxifen and flutamide) did not influence the effects of 5 microg E2 and 5 microg T on C2 and C5DRG significantly. These results demonstrate that male and female sex steroids can modulate DRG development through an epigenetic mechanism, as had been shown for the central nervous system.

Effects of 4-aminopyridine on organelle movement in cultured mouse dorsal root ganglion neurites.

PubMed

Hiruma, Hiromi; Kawakami, Tadashi

2010-03-01

Aminopyridines, widely used as a K(+) channel blocker, are membrane-permeable weak bases and have the ability to form vacuoles in the cytoplasm. The vacuoles originate from acidic organelles such as lysosomes. Here, we investigated the effects of 4-aminopyridine (4-AP) on organelle movement in neurites of cultured mouse dorsal root ganglion (DRG) neurons by using video-enhanced microscopy. Some experiments were carried out using fluorescent dyes for lysosomes and mitochondria and confocal microscopy. Treatment of DRG neurons with 4 mM 4-AP caused Brownian movement of some lysosomes within 5 min. The Brownian movement gradually became rapid and vacuoles were formed around individual lysosomes 10-20 min after the start of treatment. Axonal transport of organelles was inhibited by 4-AP. Lysosomes showing Brownian movement were not transported in longitudinal direction of the neurite and the transport of mitochondria was interrupted by vacuoles. The 4-AP-induced Brownian movement of lysosomes with vacuole formation and inhibition of axonal transport were prevented by the simultaneous treatment with vacuolar H(+) ATPase inhibitor bafilomycin A1 or in Cl(-)-free SO(4)(2-) medium. These results indicate that changes in organelle movement by 4-AP are related to vacuole formation and the vacuolar H(+) ATPase and Cl(-) are required for the effects of 4-AP.

Linear feature projection-based real-time decoding of limb state from dorsal root ganglion recordings.

PubMed

Han, Sungmin; Chu, Jun-Uk; Park, Jong Woong; Youn, Inchan

2018-05-15

Proprioceptive afferent activities recorded by a multichannel microelectrode have been used to decode limb movements to provide sensory feedback signals for closed-loop control in a functional electrical stimulation (FES) system. However, analyzing the high dimensionality of neural activity is one of the major challenges in real-time applications. This paper proposes a linear feature projection method for the real-time decoding of ankle and knee joint angles. Single-unit activity was extracted as a feature vector from proprioceptive afferent signals that were recorded from the L7 dorsal root ganglion during passive movements of ankle and knee joints. The dimensionality of this feature vector was then reduced using a linear feature projection composed of projection pursuit and negentropy maximization (PP/NEM). Finally, a time-delayed Kalman filter was used to estimate the ankle and knee joint angles. The PP/NEM approach had a better decoding performance than did other feature projection methods, and all processes were completed within the real-time constraints. These results suggested that the proposed method could be a useful decoding method to provide real-time feedback signals in closed-loop FES systems.

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

Enrichment and proteomic analysis of plasma membrane from rat dorsal root ganglions

PubMed Central

2009-01-01

Background Dorsal root ganglion (DRG) neurons are primary sensory neurons that conduct neuronal impulses related to pain, touch and temperature senses. Plasma membrane (PM) of DRG cells plays important roles in their functions. PM proteins are main performers of the functions. However, mainly due to the very low amount of DRG that leads to the difficulties in PM sample collection, few proteomic analyses on the PM have been reported and it is a subject that demands further investigation. Results By using aqueous polymer two-phase partition in combination with high salt and high pH washing, PMs were efficiently enriched, demonstrated by western blot analysis. A total of 954 non-redundant proteins were identified from the plasma membrane-enriched preparation with CapLC-MS/MS analysis subsequent to protein separation by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) or shotgun digestion. 205 (21.5%) of the identified proteins were unambiguously assigned as PM proteins, including a large number of signal proteins, receptors, ion channel and transporters. Conclusion The aqueous polymer two-phase partition is a simple, rapid and relatively inexpensive method. It is well suitable for the purification of PMs from small amount of tissues. Therefore, it is reasonable for the DRG PM to be enriched by using aqueous two-phase partition as a preferred method. Proteomic analysis showed that DRG PM was rich in proteins involved in the fundamental biological processes including material exchange, energy transformation and information transmission, etc. These data would help to our further understanding of the fundamental DRG functions. PMID:19889238

Characteristics of hyperpolarization-activated cyclic nucleotide-gated channels in dorsal root ganglion neurons at different ages and sizes.

PubMed

Hou, Baohua; Chen, Hengling; Qu, Xiangwei; Lin, Xianguang; Luo, Fang; Li, Chenhong

2015-11-11

In rat's sensory neurons, hyperpolarization-activated inward currents (Ih) play an essential role in mediating action potentials and contributing to neuronal excitability. Classified by the size of neurons and ages, we studied the Ih and transcription levels of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels using electrophysiology and the single-cell RT-PCR. In voltage-clamp studies, Ih and half-maximal activation voltage (V1/2) changed with age and size. An analysis of all HCN subtypes in dorsal root ganglion (DRG) neurons by single-cell RT-PCR was carried out. HCN1 and HCN3 in medium-small elderly neurons had a weak expression. HCN2 in newborns and HCN4 in elderly rats also had a weak expression. The aim of this study is to examine the age-related Ih and HCN channels subunits in different ages and sizes of DRG neurons. The results would be significant in understanding the physiological and pathophysiological function of different sizes of DRG neurons in different age periods.

Tentonin 3/TMEM150c Confers Distinct Mechanosensitive Currents in Dorsal-Root Ganglion Neurons with Proprioceptive Function.

PubMed

Hong, Gyu-Sang; Lee, Byeongjun; Wee, Jungwon; Chun, Hyeyeon; Kim, Hyungsup; Jung, Jooyoung; Cha, Joo Young; Riew, Tae-Ryong; Kim, Gyu Hyun; Kim, In-Beom; Oh, Uhtaek

2016-07-06

Touch sensation or proprioception requires the transduction of mechanical stimuli into electrical signals by mechanoreceptors in the periphery. These mechanoreceptors are equipped with various transducer channels. Although Piezo1 and 2 are mechanically activated (MA) channels with rapid inactivation, MA molecules with other inactivation kinetics have not been identified. Here we report that heterologously expressed Tentonin3 (TTN3)/TMEM150C is activated by mechanical stimuli with distinctly slow inactivation kinetics. Genetic ablation of Ttn3/Tmem150c markedly reduced slowly adapting neurons in dorsal-root ganglion neurons. The MA TTN3 currents were inhibited by known blockers of mechanosensitive ion channels. Moreover, TTN3 was localized in muscle spindle afferents. Ttn3-deficient mice exhibited the loss of coordinated movements and abnormal gait. Thus, TTN3 appears to be a component of a mechanosensitive channel with a slow inactivation rate and contributes to motor coordination. Identification of this gene advances our understanding of the various types of mechanosensations, including proprioception. Copyright © 2016 Elsevier Inc. All rights reserved.

[Effects of Chinese herbal medicine Yiqi Huayu Recipe on apoptosis of dorsal root ganglion neurons and expression of caspase-3 in rats with lumbar nerve root compression].

PubMed

Xu, Le-qin; Li, Xiao-feng; Zhang, You-wei; Shu, Bing; Shi, Qi; Wang, Yong-jun; Zhou, Chong-jian

2010-12-01

To observe the effects of Yiqi Huayu Recipe, a Chinese compound herbal medicine, on apoptosis of dorsal root ganglion (DRG) neurons and expression of caspase-3 in rats after lumbar nerve root compression injury. A total of 40 male Sprague-Dawley rats were randomly allocated into 4 groups: control group, untreated group, Methylcobal group and Yiqi Huayu Recipe group. Surgery was performed on rats of untreated group, Methylcobal group and Yiqi Huayu Recipe group to place a micro-silica gel on right L₄ DRG, while control group received skin and paravertebral muscle incision only. Rats in Methylcobal group and Yiqi Huayu Recipe group were given Methylcobal by intramuscular injection and Yiqi Huayu Recipe intragastrically respectively. Rats in control group and untreated group received saline intragastrically as equal amount as Yiqi Huayu Recipe group. The compressed nerve roots were harvested at the 10th day after treatment. Apoptosis of DRG neurons was detected by terminal deoxynucleotidyl transferase-mediated nick-end labeling. Caspase-3 activity and mRNA expression in compressed nerve roots were detected with spectrophotography and real-time polymerase chain reaction respectively. Apoptosis of DRG neurons was significantly increased in the rat model. The apoptosis index of untreated group was higher than that of control group (P<0.01). Yiqi Huayu Recipe and Methylcobal could reduce the apoptosis of DRG neurons, and both groups showed a lower apoptosis index than untreated group (P<0.01). Caspase-3 activity and its gene expression were significantly increased in untreated group. The levels of caspase-3 activity and its gene expression in untreated group were higher than those in control group (P<0.05 or P<0.01). Yiqi Huayu Recipe and Methylcobal could reduce the overexpression of caspase-3 mRNA, and statistically significant differences were found between the untreated group and Yiqi Huayu Recipe group or Methylcobal group (P<0.01). Lumbar nerve root compression

Control of root meristem establishment in conifers.

PubMed

Brunoni, Federica; Ljung, Karin; Bellini, Catherine

2018-06-19

The evolution of terrestrial plant life was made possible by the establishment of a root system, which enabled plants to migrate from aquatic to terrestrial habitats. During evolution, root organization has gradually progressed from a very simple to a highly hierarchical architecture. Roots are initiated during embryogenesis and branch afterwards through lateral root formation. Additionally, adventitious roots can be formed post-embryonically from aerial organs. Induction of adventitious roots forms the basis of the vegetative propagation via cuttings in horticulture, agriculture and forestry. This method, together with somatic embryogenesis, is routinely used to clonally multiply conifers. In addition to being utilized as propagation techniques, adventitious rooting and somatic embryogenesis have emerged as versatile models to study cellular and molecular mechanisms of embryo formation and organogenesis of coniferous species. Both formation of the embryonic root and the adventitious root primordia require the establishment of auxin gradients within cells that coordinate the developmental response. These processes also share key elements of the genetic regulatory networks that, for example, are triggering cell fate. This minireview gives an overview of the molecular control mechanisms associated with root development in conifers, from initiation in the embryo to post-embryonic formation in cuttings. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Regulation of the intracellular free calcium concentration in single rat dorsal root ganglion neurones in vitro.

PubMed Central

Thayer, S A; Miller, R J

1990-01-01

1. Simultaneous whole-cell patch-clamp and Fura-2 microfluorimetric recordings of calcium currents (ICa) and the intracellular free Ca2+ concentration ([Ca2+]i) were made from neurones grown in primary culture from the dorsal root ganglion of the rat. 2. Cells held at -80 mV and depolarized to 0 mV elicited a ICa that resulted in an [Ca2+]i transient which was not significantly buffered during the voltage step and lasted long after the cell had repolarized and the current ceased. The process by which the cell buffered [Ca2+]i back to basal levels could best be described with a single-exponential equation. 3. The membrane potential versus ICa and [Ca2+]i relationship revealed that the peak of the [Ca2+]i transient evoked at a given test potential closely paralleled the magnitude of the ICa suggesting that neither voltage-dependent nor Ca2(+)-induced Ca2+ release from intracellular stores made a significant contribution to the [Ca2+]i transient. 4. When the cell was challenged with Ca2+ loads of different magnitude by varying the duration or potential of the test pulse, [Ca2+]i buffering was more effective for larger Ca2+ loads. The relationship between the integrated ICa and the peak of the [Ca2+]i transient reached an asymptote at large Ca2+ loads indicating that Ca2(+)-dependent processes became more efficient or that low-affinity processes had been recruited. 5. Inhibition of Ca2+ influx with neuropeptide Y demonstrated that inhibition of a large ICa produced minor alterations in the peak of the [Ca2+]i transient, while inhibition of smaller currents produced corresponding decreases in the [Ca2+]i transient. Thus, inhibition of the ICa was reflected by a change in the peak [Ca2+]i only when submaximal Ca2+ loads were applied to the cell, implying that modulation of [Ca2+]i is dependent on the activation state of the cells. 6. Intracellular dialysis with the mitochondrial Ca2+ uptake blocker Ruthenium Red in whole-cell patch-clamp experiments removed the buffering

Dorsal Root Ganglion (DRG) Stimulation in the Treatment of Phantom Limb Pain (PLP).

PubMed

Eldabe, Sam; Burger, Katja; Moser, Heinrich; Klase, Daniel; Schu, Stefan; Wahlstedt, Anders; Vanderick, Bernard; Francois, Eric; Kramer, Jeffery; Subbaroyan, Jeyakumar

2015-10-01

Phantom limb pain (PLP) is a neuropathic condition in which pain is perceived as arising from an amputated limb. PLP is distinct from, although associated with, pain in the residual limb and nonpainful phantom sensations of the missing limb. Its treatment is extremely challenging; pharmaceutical options, while commonly employed, may be insufficient or intolerable. Neuromodulatory interventions such as spinal cord stimulation have generated mixed results and may be limited by poor somatotopic specificity. It was theorized that dorsal root ganglion (DRG) neuromodulation may be more effective. Patients trialed a DRG neurostimulation system for their PLP and were subsequently implanted if results were positive. Retrospective chart review was completed, including pain ratings on a 100-mm visual analogue scale (VAS) and patient-reported outcomes. Across eight patients, the average baseline pain rating was 85.5 mm. At follow-up (mean of 14.4 months), pain was rated at 43.5 mm. Subjective ratings of quality of life and functional capacity improved. Some patients reduced or eliminated pain medications. Patients reported precise concordance of the paresthesia with painful regions, including in their phantom limbs; in one case, stimulation eliminated PLP as well as nonpainful phantom sensations. Three patients experienced a diminution of pain relief, despite good initial outcomes. DRG neuromodulation may be an effective tool in treating this pain etiology. Clinical outcomes in this report support recent converging evidence suggesting that the DRG may be the site of PLP generation and/or maintenance. Further research is warranted to elucidate mechanisms and optimal treatment pathways. © 2015 International Neuromodulation Society.

Osthole, a herbal compound, alleviates nucleus pulposus-evoked nociceptive responses through the suppression of overexpression of acid-sensing ion channel 3 (ASIC3) in rat dorsal root ganglion

PubMed Central

He, Qiu-Lan; Chen, Yuling; Qin, Jian; Mo, Sui-Lin; Wei, Ming; Zhang, Jin-Jun; Li, Mei-Na; Zou, Xue-Nong; Zhou, Shu-Feng; Chen, Xiao-Wu; Sun, Lai-Bao

2012-01-01

Summary Background Osthole (Ost), a natural coumarin derivative, has been shown to inhibit many pro-inflammatory mediators and block voltage-gated Na+ channels. During inflammation, acidosis is an important pain inducer which activates nociceptors by gating depolarizing cationic channels, such as acid-sensing ion channel 3 (ASIC3). The aim of this study was to examine the effects of Ost on nucleus pulposus-evoked nociceptive responses and ASIC3 over-expression in the rat dorsal root ganglion, and to investigate the possible mechanism. Material/Methods Radicular pain was generated with application of nucleus pulposus (NP) to nerve root. Mechanical allodynia was evaluated using von Frey filaments with logarithmically incremental rigidity to calculate the 50% probability thresholds for mechanical paw withdrawal. ASIC3 protein expression in dorsal root ganglions (DRGs) was assessed with Western blot and immunohistochemistry. Membrane potential (MP) shift of DRG neurons induced by ASIC3-sensitive acid (pH6.5) was determined by DiBAC4 (3) fluorescence intensity (F.I.). Results The NP-evoked mechanical hyperalgesia model showed allodynia for 3 weeks, and ASIC3 expression was up-regulated in DRG neurons, reaching peak on Day 7. Epidural administration of Ost induced a remarkable and prolonged antinociceptive effect, accompanied by an inhibition of over-expressed ASIC3 protein and of abnormal shift of MP. Amiloride (Ami), an antagonist of ASIC3, strengthened the antinociceptive effect of Ost. Conclusions Up-regulation of ASIC3 expression may be associated with NP-evoked mechanical hyperalgesia. A single epidural injection of Ost decreased ASIC3 expression in DGR neurons and the pain in the NP-evoked mechanical hyperalgesia model. Osthole may be of great benefit for preventing chronic pain status often seen in lumbar disc herniation (LDH). PMID:22648244

Cells of origin in the embryonic nerve roots for NF1-associated plexiform neurofibroma

PubMed Central

Chen, Zhiguo; Liu, Chiachi; Patel, Amish J.; Liao, Chung-Ping; Wang, Yong; Le, Lu Q.

2014-01-01

Summary Neurofibromatosis type 1 is a tumor-predisposing genetic disorder. Plexiform neurofibromas are common NF1 tumors carrying a risk of malignant transformation, which is typically fatal. Little is known about mechanisms mediating initiation and identity of specific cell-type that gives rise to neurofibromas. Using cell-lineage tracing, we identify a population of GAP43+ PLP+ precursors in embryonic nerve roots as the cells of origin for these tumors and report a non-germline model of neurofibroma for preclinical drug screening to identify effective therapies. The identity of tumor cell-of-origin and facility for isolation and expansion provides fertile ground for continued analysis to define intrinsic and extrinsic factors critical for neurofibromagenesis. It also provides unique approaches to develop therapies to prevent neurofibroma formation in NF1 patients. PMID:25446898

The intriguing nature of dorsal root ganglion neurons: linking structure with polarity and function.

PubMed

Nascimento, Ana Isabel; Mar, Fernando Milhazes; Sousa, Mónica Mendes

2018-05-02

Dorsal root ganglion (DRG) neurons are the first neurons of the sensory pathway. They are activated by a variety of sensory stimuli that are then transmitted to the central nervous system. An important feature of DRG neurons is their unique morphology where a single process -the stem axon- bifurcates into a peripheral and a central axonal branch, with different functions and cellular properties. Distinctive structural aspects of the two DRG neuron branches may have important implications for their function in health and disease. However, the link between DRG axonal branch structure, polarity and function has been largely neglected in the field, and relevant information is rather scattered across the literature. In particular, ultrastructural differences between the two axonal branches are likely to account for the higher transport and regenerative ability of the peripheral DRG neuron axon when compared to the central one. Nevertheless, the cell intrinsic factors contributing to this central-peripheral asymmetry are still unknown. Here we critically review the factors that may underlie the functional asymmetry between the peripheral and central DRG axonal branches. Also, we discuss the hypothesis that DRG neurons may assemble a structure resembling the axon initial segment that may be responsible, at least in part, for their polarity and electrophysiological features. Ultimately, we suggest that the clarification of the axonal ultrastructure of DRG neurons using state-of-the-art techniques will be crucial to understand the physiology of this peculiar cell type. Copyright © 2018. Published by Elsevier Ltd.

Citral Sensing by TRANSient Receptor Potential Channels in Dorsal Root Ganglion Neurons

PubMed Central

Stotz, Stephanie C.; Vriens, Joris; Martyn, Derek; Clardy, Jon; Clapham, David E.

2008-01-01

Transient receptor potential (TRP) ion channels mediate key aspects of taste, smell, pain, temperature sensation, and pheromone detection. To deepen our understanding of TRP channel physiology, we require more diverse pharmacological tools. Citral, a bioactive component of lemongrass, is commonly used as a taste enhancer, as an odorant in perfumes, and as an insect repellent. Here we report that citral activates TRP channels found in sensory neurons (TRPV1 and TRPV3, TRPM8, and TRPA1), and produces long-lasting inhibition of TRPV1–3 and TRPM8, while transiently blocking TRPV4 and TRPA1. Sustained citral inhibition is independent of internal calcium concentration, but is state-dependent, developing only after TRP channel opening. Citral's actions as a partial agonist are not due to cysteine modification of the channels nor are they a consequence of citral's stereoisoforms. The isolated aldehyde and alcohol cis and trans enantiomers (neral, nerol, geranial, and geraniol) each reproduce citral's actions. In juvenile rat dorsal root ganglion neurons, prolonged citral inhibition of native TRPV1 channels enabled the separation of TRPV2 and TRPV3 currents. We find that TRPV2 and TRPV3 channels are present in a high proportion of these neurons (94% respond to 2-aminoethyldiphenyl borate), consistent with our immunolabeling experiments and previous in situ hybridization studies. The TRPV1 activation requires residues in transmembrane segments two through four of the voltage-sensor domain, a region previously implicated in capsaicin activation of TRPV1 and analogous menthol activation of TRPM8. Citral's broad spectrum and prolonged sensory inhibition may prove more useful than capsaicin for allodynia, itch, or other types of pain involving superficial sensory nerves and skin. PMID:18461159

Prox1 Regulates the Subtype-Specific Development of Caudal Ganglionic Eminence-Derived GABAergic Cortical Interneurons

PubMed Central

Young, Allison; Petros, Timothy; Karayannis, Theofanis; McKenzie Chang, Melissa; Lavado, Alfonso; Iwano, Tomohiko; Nakajima, Miho; Taniguchi, Hiroki; Huang, Z. Josh; Heintz, Nathaniel; Oliver, Guillermo; Matsuzaki, Fumio; Machold, Robert P.

2015-01-01

Neurogliaform (RELN+) and bipolar (VIP+) GABAergic interneurons of the mammalian cerebral cortex provide critical inhibition locally within the superficial layers. While these subtypes are known to originate from the embryonic caudal ganglionic eminence (CGE), the specific genetic programs that direct their positioning, maturation, and integration into the cortical network have not been elucidated. Here, we report that in mice expression of the transcription factor Prox1 is selectively maintained in postmitotic CGE-derived cortical interneuron precursors and that loss of Prox1 impairs the integration of these cells into superficial layers. Moreover, Prox1 differentially regulates the postnatal maturation of each specific subtype originating from the CGE (RELN, Calb2/VIP, and VIP). Interestingly, Prox1 promotes the maturation of CGE-derived interneuron subtypes through intrinsic differentiation programs that operate in tandem with extrinsically driven neuronal activity-dependent pathways. Thus Prox1 represents the first identified transcription factor specifically required for the embryonic and postnatal acquisition of CGE-derived cortical interneuron properties. SIGNIFICANCE STATEMENT Despite the recognition that 30% of GABAergic cortical interneurons originate from the caudal ganglionic eminence (CGE), to date, a specific transcriptional program that selectively regulates the development of these populations has not yet been identified. Moreover, while CGE-derived interneurons display unique patterns of tangential and radial migration and preferentially populate the superficial layers of the cortex, identification of a molecular program that controls these events is lacking. Here, we demonstrate that the homeodomain transcription factor Prox1 is expressed in postmitotic CGE-derived cortical interneuron precursors and is maintained into adulthood. We found that Prox1 function is differentially required during both embryonic and postnatal stages of development to

Pine Oil Effects on Chemical and Thermal Injury in Mice and Cultured Mouse Dorsal Root Ganglion Neurons

PubMed Central

Clark, SP; Bollag, WB; Westlund, KN; Ma, F; Falls, G; Xie, D; Johnson, M; Isales, CM; Bhattacharyya, MH

2013-01-01

A commercial resin-based pine oil derived from Pinus palustris and Pinus elliottii was the major focus of this investigation. Extracts of pine resins, needles and bark are folk medicines commonly used to treat skin ailments, including burns. The American Burn Association estimates that 500,000 people with burn injuries receive medical treatment each year; one-half of US burn victims are children, most with scald burns. This systematic study was initiated as follow-up to personal anecdotal evidence acquired over more than 10 years by MH Bhattacharyya regarding pine oil’s efficacy for treating burns. The results demonstrate that pine oil counteracted dermal inflammation in both a mouse ear model of contact irritant-induced dermal inflammation and a 2nd degree scald burn to the mouse paw. Furthermore, pine oil significantly counteracted the tactile allodynia and soft tissue injury caused by the scald burn. In mouse dorsal root ganglion (DRG) neuronal cultures, pine oil added to the medium blocked ATP-activated, but not capsaicin-activated, pain pathways, demonstrating specificity. These results together support the hypothesis that a pine-oil-based treatment can be developed to provide effective in-home care for 2nd degree burns. PMID:23595692

Effects of 4-phenyl butyric acid on high glucose-induced alterations in dorsal root ganglion neurons.

PubMed

Sharma, Dilip; Singh, Jitendra Narain; Sharma, Shyam S

2016-12-02

Mechanisms and pathways involving in diabetic neuropathy are still not fully understood but can be unified by the process of overproduction of reactive oxygen species (ROS) such as superoxide, endoplasmic reticulum (ER) stress, downstream intracellular signaling pathways and their modulation. Susceptibility of dorsal root ganglion (DRG) to internal/external hyperglycemic environment stress contributes to the pathogenesis and progression of diabetic neuropathy. ER stress leads to abnormal ion channel function, gene expression, transcriptional regulation, metabolism and protein folding. 4-phenyl butyric acid (4-PBA) is a potent and selective chemical chaperone; which may inhibit ER stress. It may be hypothesized that 4-PBA could attenuate via channels in DRG in diabetic neuropathy. Effects of 4-PBA were determined by applying different parameters of oxidative stress, cell viability, apoptosis assays and channel expression in cultured DRG neurons. Hyperglycemia-induced apoptosis in the DRG neuron was inhibited by 4-PBA. Cell viability of DRG neurons was not altered by 4-PBA. Oxidative stress was significantly blocked by the 4-PBA. Sodium channel expression was not altered by the 4-PBA. Our data provide evidence that the hyperglycemia-induced alteration may be reduced by the 4-PBA without altering the sodium channel expression. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Evaluation of the percentage of ganglion cells in the ganglion cell layer of the rodent retina

PubMed Central

Schlamp, Cassandra L.; Montgomery, Angela D.; Mac Nair, Caitlin E.; Schuart, Claudia; Willmer, Daniel J.

2013-01-01

Purpose Retinal ganglion cells comprise a percentage of the neurons actually residing in the ganglion cell layer (GCL) of the rodent retina. This estimate is useful to extrapolate ganglion cell loss in models of optic nerve disease, but the values reported in the literature are highly variable depending on the methods used to obtain them. Methods We tested three retrograde labeling methods and two immunostaining methods to calculate ganglion cell number in the mouse retina (C57BL/6). Additionally, a double-stain retrograde staining method was used to label rats (Long-Evans). The number of total neurons was estimated using a nuclear stain and selecting for nuclei that met specific criteria. Cholinergic amacrine cells were identified using transgenic mice expressing Tomato fluorescent protein. Total neurons and total ganglion cell numbers were measured in microscopic fields of 104 µm2 to determine the percentage of neurons comprising ganglion cells in each field. Results Historical estimates of the percentage of ganglion cells in the mouse GCL range from 36.1% to 67.5% depending on the method used. Experimentally, retrograde labeling methods yielded a combined estimate of 50.3% in mice. A retrograde method also yielded a value of 50.21% for rat retinas. Immunolabeling estimates were higher at 64.8%. Immunolabeling may introduce overestimates, however, with non-specific labeling effects, or ectopic expression of antigens in neurons other than ganglion cells. Conclusions Since immunolabeling methods may overestimate ganglion cell numbers, we conclude that 50%, which is consistently derived from retrograde labeling methods, is a reliable estimate of the ganglion cells in the neuronal population of the GCL. PMID:23825918

Slit/Robo Signaling Mediates Spatial Positioning of Spiral Ganglion Neurons during Development of Cochlear Innervation

PubMed Central

Wang, Sheng-zhi; Ibrahim, Leena A.; Kim, Young J.; Gibson, Daniel A.; Leung, Haiwen C.; Yuan, Wei; Zhang, Ke K.; Tao, Huizhong W.

2013-01-01

During the development of periphery auditory circuits, spiral ganglion neurons (SGNs) extend their neurites to innervate cochlear hair cells (HCs) with their soma aggregated into a cluster spatially segregated from the cochlear sensory epithelium. The molecular mechanisms underlying this spatial patterning remain unclear. In this study, in situ hybridization in the mouse cochlea suggests that Slit2 and its receptor, Robo1/2, exhibit apparently complementary expression patterns in the spiral ganglion and its nearby region, the spiral limbus. In Slit2 and Robo1/2 mutants, the spatial restriction of SGNs was disrupted. Mispositioned SGNs were found to scatter in the space between the cochlear epithelium and the main body of spiral ganglion, and the neurites of mispositioned SGNs were misrouted and failed to innervate HCs. Furthermore, in Robo1/2 mutants, SGNs were displaced toward the cochlear epithelium as an entirety. Examination of different embryonic stages in the mutants revealed that the mispositioning of SGNs was due to a progressive displacement to ectopic locations after their initial normal settlement at an earlier stage. Our results suggest that Slit/Robo signaling imposes a restriction force on SGNs to ensure their precise positioning for correct SGN-HC innervations. PMID:23884932

Citral sensing by Transient [corrected] receptor potential channels in dorsal root ganglion neurons.

PubMed

Stotz, Stephanie C; Vriens, Joris; Martyn, Derek; Clardy, Jon; Clapham, David E

2008-05-07

Transient receptor potential (TRP) ion channels mediate key aspects of taste, smell, pain, temperature sensation, and pheromone detection. To deepen our understanding of TRP channel physiology, we require more diverse pharmacological tools. Citral, a bioactive component of lemongrass, is commonly used as a taste enhancer, as an odorant in perfumes, and as an insect repellent. Here we report that citral activates TRP channels found in sensory neurons (TRPV1 and TRPV3, TRPM8, and TRPA1), and produces long-lasting inhibition of TRPV1-3 and TRPM8, while transiently blocking TRPV4 and TRPA1. Sustained citral inhibition is independent of internal calcium concentration, but is state-dependent, developing only after TRP channel opening. Citral's actions as a partial agonist are not due to cysteine modification of the channels nor are they a consequence of citral's stereoisoforms. The isolated aldehyde and alcohol cis and trans enantiomers (neral, nerol, geranial, and geraniol) each reproduce citral's actions. In juvenile rat dorsal root ganglion neurons, prolonged citral inhibition of native TRPV1 channels enabled the separation of TRPV2 and TRPV3 currents. We find that TRPV2 and TRPV3 channels are present in a high proportion of these neurons (94% respond to 2-aminoethyldiphenyl borate), consistent with our immunolabeling experiments and previous in situ hybridization studies. The TRPV1 activation requires residues in transmembrane segments two through four of the voltage-sensor domain, a region previously implicated in capsaicin activation of TRPV1 and analogous menthol activation of TRPM8. Citral's broad spectrum and prolonged sensory inhibition may prove more useful than capsaicin for allodynia, itch, or other types of pain involving superficial sensory nerves and skin.

Enkephalin-like immunoreactive principal ganglion cells and nerve fibres in the inferior mesenteric ganglion of the cat.

PubMed

Balayadi, M; Jule, Y; Cupo, A

1988-10-05

The occurrence and distribution of methionine-enkephalin (ME), leucine-enkephalin (LE) and methionine-enkephalin-Arg6-Gly7-Leu8 (MERGL)-like (LI) immunoreactive material in the inferior mesenteric ganglion (IMG) of the cat were studied by immunohistochemical techniques using the peroxidase-antiperoxidase method. Numerous ME-Li, LE-Li and MERGL-Li immunoreactive fibres with the same distribution pattern were observed. They were varicose and often surrounded closely neighbouring unlabelled ganglion cell bodies. Sometimes they ran in strands between ganglion cells. ME-Li immunoreactive material was detected in a number of cell bodies, the diameter of which was similar to that of unlabelled principal ganglion cell bodies, and which were probably Enk-Li-containing principal ganglion cells. These immunoreactive cells were often surrounded by ME-Li immunoreactive fibres. No LE-Li or MERGL-Li immunoreactive ganglion cell bodies were observed. The presence of ME-Li immunoreactive principal ganglion cells raises the possibility that the Enk-Li immunoreactive fibres present in the IMG may have a prevertebral ganglionic source. The possibility that the Enk-Li material present in nerve fibres might be derived from preproenkephalin-A was suggested by the occurrence of MERGL-Li immunoreactivity.

Inhibitory Effects of Honokiol on the Voltage-Gated Potassium Channels in Freshly Isolated Mouse Dorsal Root Ganglion Neurons.

PubMed

Sheng, Anqi; Zhang, Yan; Li, Guang; Zhang, Guangqin

2018-02-01

Voltage-gated potassium (K V ) currents, subdivided into rapidly inactivating A-type currents (I A ) and slowly inactivating delayed rectifier currents (I K ), play a fundamental role in modulating pain by controlling neuronal excitability. The effects of Honokiol (Hon), a natural biphenolic compound derived from Magnolia officinalis, on K V currents were investigated in freshly isolated mouse dorsal root ganglion neurons using the whole-cell patch clamp technique. Results showed that Hon inhibited I A and I K in concentration-dependent manner. The IC 50 values for block of I A and I K were 30.5 and 25.7 µM, respectively. Hon (30 µM) shifted the steady-state activation curves of I A and I K to positive potentials by 17.6 and 16.7 mV, whereas inactivation and recovery from the inactivated state of I A were unaffected. These results suggest that Hon preferentially interacts with the active states of the I A and I K channels, and has no effect on the resting state and inactivated state of the I A channel. Blockade on K + channels by Hon may contribute to its antinociceptive effect, especially anti-inflammatory pain.

Inhibition of acid-sensing ion channels by levo-tetrahydropalmatine in rat dorsal root ganglion neurons.

PubMed

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

2015-02-01

Levo-tetrahydropalmatine (l-THP), a main bioactive Chinese herbal constituent from the genera Stephania and Corydalis, has been in use in clinical practice for years in China as a traditional analgesic agent. However, the mechanism underlying the analgesic action of l-THP is poorly understood. This study shows that l-THP can exert an inhibitory effect on the functional activity of native acid-sensing ion channels (ASICs), which are believed to mediate pain caused by extracellular acidification. l-THP dose dependently decreased the amplitude of proton-gated currents mediated by ASICs in rat dorsal root ganglion (DRG) neurons. l-THP shifted the proton concentration-response curve downward, with a decrease of 40.93% ± 8.45% in the maximum current response to protons, with no significant change in the pH0.5 value. Moreover, l-THP can alter the membrane excitability of rat DRG neurons to acid stimuli. It significantly decreased the number of action potentials and the amplitude of the depolarization induced by an extracellular pH drop. Finally, peripherally administered l-THP inhibited the nociceptive response to intraplantar injection of acetic acid in rats. These results indicate that l-THP can inhibit the functional activity of ASICs in dissociated primary sensory neurons and relieve acidosis-evoked pain in vivo, which for the first time provides a novel peripheral mechanism underlying the analgesic action of l-THP. © 2014 Wiley Periodicals, Inc.

Decreased voltage-gated potassium currents in rat dorsal root ganglion neurons after chronic constriction injury.

PubMed

Xiao, Yun; Wu, Yang; Zhao, Bo; Xia, Zhongyuan

2016-01-20

Voltage-gated potassium channels (KV) regulate pain transmission by controlling neuronal excitability. Changes in KV expression patterns may thus contribute toward hyperalgesia following nerve injury. The aim of this study was to characterize KV current density in dorsal root ganglion (DRG) neurons following chronic constriction injury (CCI) of the right sciatic nerve, a robust model of post-traumatic neuropathic pain. The study examined changes in small-diameter potassium ion currents (<30 µm) in neurons in the L4-L6 DRG following CCI by whole-cell patch-clamping and the association with post-CCI mechanical and thermal nociceptive thresholds. Compared with the control group, 7 days after CCI, the mechanical force and temperature required to elicit ipsilateral foot withdrawal decreased significantly, indicating tactile allodynia and thermal hyperalgesia. Post-CCI neurons had a significantly lower rheobase current and depolarized resting membrane potential than controls, suggesting KV current downregulation. Some ipsilateral DRG neurons also had spontaneous action potentials and repetitive firing. There was a 55% reduction in the total KV current density caused by a 55% decrease in the sustained delayed rectifier potassium ion current (IK) density and a 17% decrease in the transient A-type potassium ion current (IA) density. These results indicated that changes in DRG neuron IK and IA current density and concomitant afferent hyperexcitability may contribute toward neuropathic pain following injury. The rat CCI model may prove valuable for examining pathogenic mechanisms and potential therapies, such as KV channel modulators.

Modulation of nano-selenium on tetrodotoxin-sensitive voltage-gated sodium currents in rat dorsal root ganglion neurons.

PubMed

Yuan, Huijun; Lan, Tonghan; Lin, Jiarui

2005-01-01

Nano-Selenium, a novel Nano technology production, was demonstrated to be useful in medical and scientific researches. Here, we investigated the effects of Nano-Selenium on tetrodotoxin-sensitive (TTX-S) voltage-dependent Na⁺channels in isolated rat dorsal root ganglion neurons, using whole-cell patch-clamp method. Nano-Selenium irreversibly decreased TTX-S Na⁺current (INa) in a concentration-dependent manner and shifted the maximum of the current/voltage relationship from -67mV to -52mV, without modifying the threshold potential of the current. Nano-Selenium shifted the steady-state activation and inactivation curves to the left. In the contrast of Na2SeO3, the inhibition effect of 1nM Nano-Se was much stronger. The cell treated with 1nM Na2SeO3firstly, still respond to futher addition of 1nM Nano-Selenium. These results prove Nano-Selenium to be a novel antiagonist, acted within the channel pore, not on or near the exterior surface of the channel protein where it would experience the membrane electric field, which possesses a distinct binding site from Na2SeO3.

Spontaneous voltage and current fluctuations in tissue cultured mouse dorsal root ganglion cells.

PubMed

Mathers, D A; Barker, J L

1984-02-13

Fetal mouse dorsal root ganglion (DRG) neurons were maintained in primary dissociated cell culture for periods of 7 days to 3 months. Intracellular recordings from these cells revealed the presence of spontaneous subthreshold potentials in 101/177 neurons studied. When measured at the resting membrane potential, these spontaneous voltage events took two forms: (a) high frequency potential fluctuations several millivolts in peak-to-peak amplitude and (b) small, discrete hyperpolarizations. Neurons exhibiting either type of event were designated as 'active' DRG cells. No spontaneous potentials were seen in DRG cells hyperpolarized to membrane voltages more negative than -64 +/- 11.5 mV (n = 5 cells). Under voltage-clamp conditions, the subthreshold potentials of active DRG cells were replaced by fluctuations in outward current. The power spectral density, S(f) of these current fluctuations was approximated by an equation of the form S(f) = (S(o)/[1 + (f/fc) alpha] where 2 less than or equal to a less than or equal to 3 and the half-power frequency fc = 11.3 +/- 3.1 Hz at 23 degrees C (n = 17 cells). The spontaneous voltage fluctuations of active DRG cells were abolished in Ca2+-free saline, and of the divalent metal cations Sr2+, Mg2+, Ba2+, Co2+ and Mn2+, only Sr2+ could substitute for Ca2+ in the maintenance of this activity. Tetraethylammonium ions (1-10 mM) reversibly blocked the spontaneous potentials, while caffeine (10 mM) increased the frequency of these events. The spontaneous voltage fluctuations were not dependent on the presence of spinal cord neurons in the culture plate, and they were also observed in cultured DRG cells derived from adult mice.

Gasserian Ganglion and Retrobulbar Nerve Block in the Treatment of Ophthalmic Postherpetic Neuralgia: A Case Report.

PubMed

Huang, Jie; Ni, Zhongge; Finch, Philip

2017-09-01

Varicella zoster virus reactivation can cause permanent histological changes in the central and peripheral nervous system. Neural inflammatory changes or damage to the dorsal root ganglia sensory nerve fibers during reactivation can lead to postherpetic neuralgia (PHN). For PHN of the first division of the fifth cranial nerve (ophthalmic division of the trigeminal ganglion), there is evidence of inflammatory change in the ganglion and adjacent ocular neural structures. First division trigeminal nerve PHN can prove to be difficult and sometimes even impossible to manage despite the use of a wide range of conservative measures, including anticonvulsant and antidepressant medication. Steroids have been shown to play an important role by suppressing neural inflammatory processes. We therefore chose the trigeminal ganglion as an interventional target for an 88-year-old woman with severe ophthalmic division PHN after she failed to respond to conservative treatment. Under fluoroscopic guidance, a trigeminal ganglion nerve block was performed with lidocaine combined with dexamethasone. A retrobulbar block with lidocaine and triamcinolone settled residual oculodynia. At 1-year follow-up, the patient remained pain free and did not require analgesic medication. To our knowledge, this is the first reported case of ophthalmic division PHN successfully treated with a combination of trigeminal ganglion and retrobulbar nerve block using a local anesthetic agent and steroid for central and peripheral neural inflammatory processes. © 2016 World Institute of Pain.

Neuronal and glial expression of inward rectifier potassium channel subunits Kir2.x in rat dorsal root ganglion and spinal cord.

PubMed

Murata, Yuzo; Yasaka, Toshiharu; Takano, Makoto; Ishihara, Keiko

2016-03-23

Inward rectifier K(+) channels of the Kir2.x subfamily play important roles in controlling the neuronal excitability. Although their cellular localization in the brain has been extensively studied, only a few studies have examined their expression in the spinal cord and peripheral nervous system. In this study, immunohistochemical analyses of Kir2.1, Kir2.2, and Kir2.3 expression were performed in rat dorsal root ganglion (DRG) and spinal cord using bright-field and confocal microscopy. In DRG, most ganglionic neurons expressed Kir2.1, Kir2.2 and Kir2.3, whereas satellite glial cells chiefly expressed Kir2.3. In the spinal cord, Kir2.1, Kir2.2 and Kir2.3 were all expressed highly in the gray matter of dorsal and ventral horns and moderately in the white matter also. Within the gray matter, the expression was especially high in the substantia gelatinosa (lamina II). Confocal images obtained using markers for neuronal cells, NeuN, and astrocytes, Sox9, showed expression of all three Kir2 subunits in both neuronal somata and astrocytes in lamina I-III of the dorsal horn and the lateral spinal nucleus of the dorsolateral funiculus. Immunoreactive signals other than those in neuronal and glial somata were abundant in lamina I and II, which probably located mainly in nerve fibers or nerve terminals. Colocalization of Kir2.1 and 2.3 and that of Kir2.2 and 2.3 were present in neuronal and glial somata. In the ventral horn, motor neurons and interneurons were also immunoreactive with the three Kir2 subunits. Our study suggests that Kir2 channels composed of Kir2.1-2.3 subunits are expressed in neuronal and glial cells in the DRG and spinal cord, contributing to sensory transduction and motor control. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Gymnopilin--a substance produced by the hallucinogenic mushroom, Gymnopilus junonius--mobilizes intracellular Ca(2+) in dorsal root ganglion cells.

PubMed

Miyazaki, Shunsuke; Kitamura, Naoki; Nishio, Aiko; Tanaka, Saki; Kayano, Tomohiko; Moriya, Taiki; Ichiyanagi, Tsuyoshi; Shimomura, Norihiro; Shibuya, Izumi; Aimi, Tadanori

2012-04-01

Gymnopilus junonius is a widely spread mushroom in Japan and well known as a hallucinogenic mushroom. Gymnopilin was purified from the fruiting body of G. junonius and was reported to act on the spinal cord and depolarize motoneurons. This is the only evidence that gymnopilin has a biological effect on animals and no mechanism of the action has been determined at all. In this study, we examined effects of gymnopilin on intracellular Ca(2+) concentrations ([Ca(2+)](i)) of cultured cells isolated from the dorsal root ganglion (DRG) of the rat. The cell culture consisted of neurons and non-neuronal cells. Gymnopilin increased [Ca(2+)](i) in both the types of cells. The gymnopilinevoked [Ca(2+)](i) rise in the non-neuronal cells was inhibited by cyclopiazonic acid and U-73122, inhibitors of Ca(2+)-ATPase of the intracellular Ca(2+) store and phospholipase C, respectively, but not by removal of extracellular Ca(2+). These results indicate that gymnopilin activated phospholipase C and mobilize Ca(2+) from the intracellular Ca(2+) store in non-neuronal cells from the DRG. This is the first report to show that gymnopilin directly acts on cells isolated from the mammalian nervous system.

Retrospective review of the efficacy and safety of repeated pulsed and continuous radiofrequency lesioning of the dorsal root ganglion/segmental nerve for lumbar radicular pain.

PubMed

Nagda, Jyotsna V; Davis, Craig W; Bajwa, Zahid H; Simopoulos, Thomas T

2011-01-01

Chronic lumbosacral radicular pain is a common source of radiating leg pain seen in pain management patients. These patients are frequently managed conservatively with multiple modalities including medications, physical therapy, and epidural steroid injections. Radiofrequency has been used to treat chronic radicular pain for over 30 years; however, there is a paucity of literature about the safety and efficacy of repeat radiofrequency lesioning. To determine the safety, success rate, and duration of pain relief of repeat pulsed radiofrequency (PRF) and continuous radiofrequency (CRF) lesioning of the dorsal root ganglion (DRG)/ sacral segmental nerves (SN) in patients with chronic lumbosacral radicular pain. Retrospective chart review Outpatient multidisciplinary pain center Medical record review of patients who were treated with pulsed and continuous radiofrequency lesioning of the lumbar dorsal root ganglia and segmental nerves and who reported initial success were evaluated for recurrence of pain and repeat radiofrequency treatment. Responses to subsequent treatments were compared to initial treatments for success rates, average duration of relief, and adverse neurologic side-effects. Retrospective chart review without a control group. Twenty-six women and 24 men were identified who received 50% pain relief or better after PRF and CRF of the lumbar DRG/ sacral SN for lumbosacral radicular pain. The mean age was 62 years (range, 25-86). The mean duration of relief for the 40 patients who had 2 treatments was 4.7 months (range 0-24; Se [standard error] 0.74). Twenty-eight patients had 3 treatments with an average duration of relief of 4.5 months (range 0-19 months; Se 0.74). Twenty patients had 4 treatments with a mean duration of relief of 4.4 months (range 0.5-18; Se 0.95) and 18 patients who had 5 or more treatments received an average duration of relief of 4.3 months (range 0.5-18; Se 1.03). The average duration of relief and success frequency remained

[Botulinum toxin type A does not affect spontaneous discharge but blocks sympathetic-sensory coupling in chronically compressed rat dorsal root ganglion neurons].

PubMed

Yang, Hong-jun; Peng, Kai-run; Hu, San-jue; Duan, Jian-hong

2007-11-01

To study the effect of botulinum toxin type A (BTXA) on spontaneous discharge and sympathetic- sensory coupling in chronically compressed dorsal root ganglion (DRG) neurons in rats. In chronically compressed rat DRG, spontaneous activities of the single fibers from DRG neurons were recorded and their changes observed after BTAX application on the damaged DGR. Sympathetic modulation of the spontaneous discharge from the compressed DRG neurons was observed by electric stimulation of the lumbar sympathetic trunk, and the changes in this effect were evaluated after intravenous BTXA injection in the rats. Active spontaneous discharges were recorded in the injured DRG neurons, and 47 injured DRG neurons responded to Ca2+-free artificial cerebrospinal fluid but not to BTXA treatment. Sixty-four percent of the neurons in the injured DRG responded to sympathetic stimulation, and this response was blocked by intravenously injection of BTXA. BTXA does not affect spontaneous activities of injured DRG neurons, but blocks sympathetic-sensory coupling in these neurons.

Cytokinin-induced promotion of root meristem size in the fern Azolla supports a shoot-like origin of euphyllophyte roots.

PubMed

de Vries, Jan; Fischer, Angela Melanie; Roettger, Mayo; Rommel, Sophie; Schluepmann, Henriette; Bräutigam, Andrea; Carlsbecker, Annelie; Gould, Sven Bernhard

2016-01-01

The phytohormones cytokinin and auxin orchestrate the root meristem development in angiosperms by determining embryonic bipolarity. Ferns, having the most basal euphyllophyte root, form neither bipolar embryos nor permanent embryonic primary roots but rather an adventitious root system. This raises the questions of how auxin and cytokinin govern fern root system architecture and whether this can tell us something about the origin of that root. Using Azolla filiculoides, we characterized the influence of IAA and zeatin on adventitious fern root meristems and vasculature by Nomarski microscopy. Simultaneously, RNAseq analyses, yielding 36,091 contigs, were used to uncover how the phytohormones affect root tip gene expression. We show that auxin restricts Azolla root meristem development, while cytokinin promotes it; it is the opposite effect of what is observed in Arabidopsis. Global gene expression profiling uncovered 145 genes significantly regulated by cytokinin or auxin, including cell wall modulators, cell division regulators and lateral root formation coordinators. Our data illuminate both evolution and development of fern roots. Promotion of meristem size through cytokinin supports the idea that root meristems of euphyllophytes evolved from shoot meristems. The foundation of these roots was laid in a postembryonically branching shoot system. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Pressure wave injuries to rat dorsal root ganglion cells in culture caused by high-energy missiles.

PubMed

Suneson, A; Hansson, H A; Lycke, E; Seeman, T

1989-01-01

A high-energy missile impact in an extremity of an animal creates a shock wave which is rapidly dispersed as a burst of oscillating pressure waves that traverses the entire body causing local, regional, and distant injuries. The present study was performed on dorsal root ganglion (DRG) cells, cultured for 3 weeks, to elucidate the cellular mechanism for damage of nerve cells, using a simplified test system. A model system was developed allowing exposure of DRG cultures to a burst of high-frequency oscillating pressure waves, comparable to those recorded in animals after high-energy missile extremity impact. The pressure waves were induced by impact of a high-energy missile in a rubber tube filled with water, in which nerve cell cultures were kept in a closed rubber glove filled with tissue culture medium. The pressure waves had a duration of 0.5-1.5 ms and a frequency spectrum ranging from 0-250 kHz. Within minutes the neurites showed changes in their microtubules. In addition, varicosities, enriched with tubulin immunoreactive material, became irregularly studded along the nerve cell processes. Scattered DRG cells were initially permeable to the marker complex Evans-blue albumin (EBA), used as an indicator of the ability of the plasma membranes to exclude proteins. After 6 hr, however, almost every DRG neuron was intensely stained by EBA. Concomitantly, there was swelling of the nerve cell cytoplasm and organelles, and, to a variable extent, neurofilament tangles were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of dorsal root ganglion K2P1.1 in peripheral nerve injury-induced neuropathic pain

PubMed Central

Mao, Qingxiang; Yuan, Jingjing; Xiong, Ming; Wu, Shaogen; Chen, Liyong; Bekker, Alex; Yang, Tiande

2017-01-01

Peripheral nerve injury-caused hyperexcitability and abnormal ectopic discharges in the primary sensory neurons of dorsal root ganglion (DRG) play a key role in neuropathic pain development and maintenance. The two-pore domain background potassium (K2P) channels have been identified as key determinants of the resting membrane potential and neuronal excitability. However, whether K2P channels contribute to neuropathic pain is still elusive. We reported here that K2P1.1, the first identified mammalian K2P channel, was highly expressed in mouse DRG and distributed in small-, medium-, and large-sized DRG neurons. Unilateral lumbar (L) 4 spinal nerve ligation led to a significant and time-dependent reduction of K2P1.1 mRNA and protein in the ipsilateral L4 DRG, but not in the contralateral L4 or ipsilateral L3 DRG. Rescuing this reduction through microinjection of adeno-associated virus-DJ expressing full-length K2P1.1 mRNA into the ipsilateral L4 DRG blocked spinal nerve ligation-induced mechanical, thermal, and cold pain hypersensitivities during the development and maintenance periods. This DRG viral microinjection did not affect acute pain and locomotor function. Our findings suggest that K2P1.1 participates in neuropathic pain development and maintenance and may be a potential target in the management of this disorder. PMID:28326939

First report of important causal relationship between the Adamkiewicz artery vasospasm and dorsal root ganglion cell degeneration in spinal subarachnoid hemorrhage: An experimental study using a rabbit model.

PubMed

Turkmenoglu, Osman N; Kanat, Ayhan; Yolas, Coskun; Aydin, Mehmet Dumlu; Ezirmik, Naci; Gundogdu, Cemal

2017-01-01

The blood supply of the lower spinal cord is heavily dependent on the artery of Adamkiewicz. The goal of this study was to elucidate the effects of lumbar subarachnoid hemorrhage (SAH) on the lumbar 4 dorsal root ganglion (L4DRG) cells secondary to Adamkiewicz artery (AKA) vasospasm. This study was conducted on 20 rabbits, which were randomly divided into three groups: Spinal SAH ( n = 8), serum saline (SS) (SS; n = 6) and control ( n = 6) groups. Experimental spinal SAH was performed. After 20 days, volume values of AKA and neuron density of L4DRG were analyzed. The mean alive neuron density of the L4DRG was 15420 ± 1240/mm 3 and degenerated neuron density was 1045 ± 260/mm 3 in the control group. Whereas, the density of living and degenerated neurons density were 12930 ± 1060/mm 3 and 1365 ± 480/mm 3 in serum saline (SS), 9845 ± 1028/mm 3 and 4560 ± 1340/mm 3 in the SAH group. The mean volume of imaginary AKAs was estimated as 1,250 ± 0,310 mm 3 in the control group and 1,030 ± 0,240 mm 3 in the SF group and 0,910 ± 0,170 mm 3 in SAH group. Volume reduction of the AKAs and neuron density L4DRG were significantly different between the SAH and other two groups ( P < 0.05). Decreased volume of the lumen of the artery of Adamkiewicz was observed in animals with SAH compared with controls. Increased degeneration the L4 dorsal root ganglion in animals with SAH was also noted. Our findings will aid in the planning of future experimental studies and determining the clinical relevance on such studies.

First report of important causal relationship between the Adamkiewicz artery vasospasm and dorsal root ganglion cell degeneration in spinal subarachnoid hemorrhage: An experimental study using a rabbit model

PubMed Central

Turkmenoglu, Osman N.; Kanat, Ayhan; Yolas, Coskun; Aydin, Mehmet Dumlu; Ezirmik, Naci; Gundogdu, Cemal

2017-01-01

Background: The blood supply of the lower spinal cord is heavily dependent on the artery of Adamkiewicz. The goal of this study was to elucidate the effects of lumbar subarachnoid hemorrhage (SAH) on the lumbar 4 dorsal root ganglion (L4DRG) cells secondary to Adamkiewicz artery (AKA) vasospasm. Materials and Methods: This study was conducted on 20 rabbits, which were randomly divided into three groups: Spinal SAH (n = 8), serum saline (SS) (SS; n = 6) and control (n = 6) groups. Experimental spinal SAH was performed. After 20 days, volume values of AKA and neuron density of L4DRG were analyzed. Results: The mean alive neuron density of the L4DRG was 15420 ± 1240/mm3 and degenerated neuron density was 1045 ± 260/mm3 in the control group. Whereas, the density of living and degenerated neurons density were 12930 ± 1060/mm3 and 1365 ± 480/mm3 in serum saline (SS), 9845 ± 1028/mm3 and 4560 ± 1340/mm3 in the SAH group. The mean volume of imaginary AKAs was estimated as 1,250 ± 0,310 mm3 in the control group and 1,030 ± 0,240 mm3 in the SF group and 0,910 ± 0,170 mm3 in SAH group. Volume reduction of the AKAs and neuron density L4DRG were significantly different between the SAH and other two groups (P < 0.05). Conclusion: Decreased volume of the lumen of the artery of Adamkiewicz was observed in animals with SAH compared with controls. Increased degeneration the L4 dorsal root ganglion in animals with SAH was also noted. Our findings will aid in the planning of future experimental studies and determining the clinical relevance on such studies. PMID:28413527

Ganglion Cyst

MedlinePlus

... with aspiration and injection therapy, there are nevertheless cases in which the ganglion cyst returns. Find an ACFAS Physician Search Search Tools Find an ACFAS Physician: Search by Mail Address ...

Changes in Dorsal Root Ganglion Gene Expression in Response to Spinal Cord Stimulation.

PubMed

Tilley, Dana M; Cedeño, David L; Kelley, Courtney A; DeMaegd, Margaret; Benyamin, Ramsin; Vallejo, Ricardo

Spinal cord stimulation (SCS) has been shown to influence pain-related genes in the spinal cord directly under the stimulating electrodes. There is limited information regarding changes occurring at the dorsal root ganglion (DRG). This study evaluates gene expression in the DRG in response to SCS therapy. Rats were randomized into experimental or control groups (n = 6 per group). Experimental animals underwent spared-nerve injury, implantation of lead, and continuous SCS (72 hours). Behavioral assessment for mechanical hyperalgesia was conducted to compare responses after injury and treatment. Ipsilateral DRG tissue was collected, and gene expression quantified for interleukin 1b (IL-1b), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), GABA B receptor 1 (GABAbr1), substance P (subP), Integrin alpha M (ITGAM), sodium/potassium ATP-ase (Na/K ATPase), fos proto-oncogene (cFOS), serotonin receptor 3A (5HT3r), galanin (Gal), vasoactive intestinal peptide (VIP), neuropeptide Y (NpY), glial fibrillary acidic protein (GFAP), and brain derived neurotropic factor (BDNF) via quantitative polymerase chain reaction. Statistical significance was established using analysis of variance (ANOVA), independent t tests, and Pearson correlation tests. Expression of IL-1b and IL-6 was reversed following SCS therapy relative to the increase caused by the injury model. Both GABAbr1 and Na/K ATPase were significantly up-regulated upon implantation of the lead, and SCS therapy reversed their expression to within control levels. Pearson correlation analyses reveal that GABAbr1 and Na/K ATPase expression was dependent on the stimulating current intensity. Spinal cord stimulation modulates expression of key pain-related genes in the DRG. Specifically, SCS led to reversal of IL-1b and IL-6 expression induced by injury. Interleukin 6 expression was still significantly larger than in sham animals, which may correlate to residual sensitivity following continuous SCS treatment. In addition

Molecular biology of retinal ganglion cells.

PubMed Central

Xiang, M; Zhou, H; Nathans, J

1996-01-01

Retinal ganglion cells are the output neurons that encode and transmit information from the eye to the brain. Their diverse physiologic and anatomic properties have been intensively studied and appear to account well for a number of psychophysical phenomena such as lateral inhibition and chromatic opponency. In this paper, we summarize our current view of retinal ganglion cell properties and pose a number of questions regarding underlying molecular mechanisms. As an example of one approach to understanding molecular mechanisms, we describe recent work on several POU domain transcription factors that are expressed in subsets of retinal ganglion cells and that appear to be involved in ganglion cell development. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:8570601

Isolated dorsal root ganglion neurones inhibit receptor-dependent adenylyl cyclase activity in associated glial cells

PubMed Central

Ng, KY; Yeung, BHS; Wong, YH; Wise, H

2013-01-01

Background and Purpose Hyper-nociceptive PGE2 EP4 receptors and prostacyclin (IP) receptors are present in adult rat dorsal root ganglion (DRG) neurones and glial cells in culture. The present study has investigated the cell-specific expression of two other Gs-protein coupled hyper-nociceptive receptor systems: β-adrenoceptors and calcitonin gene-related peptide (CGRP) receptors in isolated DRG cells and has examined the influence of neurone–glial cell interactions in regulating adenylyl cyclase (AC) activity. Experimental Approach Agonist-stimulated AC activity was determined in mixed DRG cell cultures from adult rats and compared with activity in DRG neurone-enriched cell cultures and pure DRG glial cell cultures. Key Results Pharmacological analysis showed the presence of Gs-coupled β2-adrenoceptors and CGRP receptors, but not β1-adrenoceptors, in all three DRG cell preparations. Agonist-stimulated AC activity was weakest in DRG neurone-enriched cell cultures. DRG neurones inhibited IP receptor-stimulated glial cell AC activity by a process dependent on both cell–cell contact and neurone-derived soluble factors, but this is unlikely to involve purine or glutamine receptor activation. Conclusions and Implications Gs-coupled hyper-nociceptive receptors are readily expressed on DRG glial cells in isolated cell cultures and the activity of CGRP, EP4 and IP receptors, but not β2-adrenoceptors, in glial cells is inhibited by DRG neurones. Studies using isolated DRG cells should be aware that hyper-nociceptive ligands may stimulate receptors on glial cells in addition to neurones, and that variable numbers of neurones and glial cells will influence absolute measures of AC activity and affect downstream functional responses. PMID:22924655

A novel astrovirus associated with encephalitis and ganglionitis in domestic sheep.

PubMed

Pfaff, F; Schlottau, K; Scholes, S; Courtenay, A; Hoffmann, B; Höper, D; Beer, M

2017-06-01

In June 2013, a 4-year-old Welsh Mountain ewe and in March 2014 a 10-day-old lamb of the same breed and the same flock presented progressive neurological signs including depressed sensorium, tremor, and unusual behaviour. Neuropathological examination of the brain and spinal cord detected non-suppurative polioencephalomyelitis and dorsal root ganglionitis, characteristic of a neurotropic viral agent in both sheep. Metagenomic analysis of different tissue samples from both animals identified a novel Ovine Astrovirus (OvAstV). The presence of viral genome in the central nervous system was confirmed by RT-qPCR. Although the cases presented nine months apart, the identified OvAstV shared nearly identical sequences, differing in only three nucleotide positions across the complete genome. Phylogenetic analysis revealed a close relation of OvAstV to neurotropic bovine astroviruses and an enteric OvAstV. In conclusion, these are the first reported cases of astrovirus infection in domestic sheep that were associated with encephalitis and ganglionitis. © 2017 Blackwell Verlag GmbH.

Chronic Compression of the Dorsal Root Ganglion Enhances Mechanically Evoked Pain Behavior and the Activity of Cutaneous Nociceptors in Mice.

PubMed

Wang, Tao; Hurwitz, Olivia; Shimada, Steven G; Qu, Lintao; Fu, Kai; Zhang, Pu; Ma, Chao; LaMotte, Robert H

2015-01-01

Radicular pain in humans is usually caused by intraforaminal stenosis and other diseases affecting the spinal nerve, root, or dorsal root ganglion (DRG). Previous studies discovered that a chronic compression of the DRG (CCD) induced mechanical allodynia in rats and mice, with enhanced excitability of DRG neurons. We investigated whether CCD altered the pain-like behavior and also the responses of cutaneous nociceptors with unmyelinated axons (C-fibers) to a normally aversive punctate mechanical stimulus delivered to the hairy skin of the hind limb of the mouse. The incidence of a foot shaking evoked by indentation of the dorsum of foot with an aversive von Frey filament (tip diameter 200 μm, bending force 20 mN) was significantly higher in the foot ipsilateral to the CCD surgery as compared to the contralateral side on post-operative days 2 to 8. Mechanically-evoked action potentials were electrophysiologically recorded from the L3 DRG, in vivo, from cell bodies visually identified as expressing a transgenically labeled fluorescent marker (neurons expressing either the receptor MrgprA3 or MrgprD). After CCD, 26.7% of MrgprA3+ and 32.1% MrgprD+ neurons exhibited spontaneous activity (SA), while none of the unoperated control neurons had SA. MrgprA3+ and MrgprD+ neurons in the compressed DRG exhibited, in comparison with neurons from unoperated control mice, an increased response to the punctate mechanical stimuli for each force applied (6, 20, 40, and 80 mN). We conclude that CCD produced both a behavioral hyperalgesia and an enhanced response of cutaneous C-nociceptors to aversive punctate mechanical stimuli.

[Effects of Jinmaitong capsule on oxidative stress and cell apoptosis of dorsal root ganglion in diabetic rats].

PubMed

Liu, Wei; Liang, Xiao-chun; Sun, Qing; Wang, Pu-yan; Zhao, Li; Huang, Wen-zhi; Li, Bo-wu

2013-12-01

To study the effects of Jinmaitong capsule on oxidative stress and cell apoptosis of dorsal root ganglion (DRG) in rats with diabetic peripheral neuropathy. Sixty male SD rats were randomly divided into normal group and model groups. The diabetic rat models were established using Streptozotocin (STZ) method (60 mg/kg of intraperitoneal injection), and then randomly divided Jinmaitong low, middle, and high-dose groups and vitamin C group. All the experimental rats were sacrificed at 16-week and then the DRG was isolated. The morphological changes of DRG were observed using the Nissl's staining, and the NADPH oxidase subunit p22-phox, Cyt C, Bcl-2, and Caspase-3 of DRG in rats were detected by immunohistochemistry and quantitative reverse transcription PCR (qRT-PCR). Cell apoptosis was detected by TUNEL. Compared with the model group, the expressions of NADPH oxidase subunit p22-phox protein, Cyt expression of C protein, Caspase-3 protein, and mRNA cell apoptosis rate in each treatment group significantly decreased whereas the expressions of Bcl-2 mRNA and protein significantly increased (P<0.05 or P<0.01). The Jinmaitong high-dose group had the best effect and was significantly different from that of the vitamin C group (P<0.01). Jinmaitong capsule can prevent the nerve injury in rats with diabetic peripheral neuropathy by inhibiting oxidative stress and decreasing the apoptosis. The high-dose Jinmaitong capsule has the best effect and is superior to vitamin C.

TRPV2 is activated by cannabidiol and mediates CGRP release in cultured rat dorsal root ganglion neurons.

PubMed

Qin, Ning; Neeper, Michael P; Liu, Yi; Hutchinson, Tasha L; Lubin, Mary Lou; Flores, Christopher M

2008-06-11

Transient receptor potential V2 (TRPV2) has been proposed to be a high-threshold thermosensor. However, further elucidation of the channel properties and physiological role of TRPV2 have been hindered by the lack of selective pharmacological tools as well as by the species-dependent differences in the activation of this channel. In the present study, we have used cell-based calcium mobilization and electrophysiological assays to identify and characterize several novel cannabinoid TRPV2 agonists. Among these, cannabidiol was found to be the most robust and potent (EC(50) = 3.7 microM), followed by Delta(9)-tetrahydrocannabinol (EC(50) = 14 microM) and cannabinol (EC(50) = 77.7 microM). We also demonstrated that cannabidiol evoked a concentration-dependent release of calcitonin gene-related peptide (CGRP) from cultured rat dorsal root ganglion neurons in a cannabinoid receptor- and TRPV1-independent manner. Moreover, the cannabidiol-evoked CGRP release depended on extracellular calcium and was blocked by the nonselective TRP channel blocker, ruthenium red. We further provide evidence through the use of small interfering RNA knockdown and repetitive stimulation studies, to show that cannabidiol-evoked CGRP release is mediated, at least in part, by TRPV2. Together, these data suggest not only that TRPV2 may comprise a mechanism whereby cannabidiol exerts its clinically beneficial effects in vivo, but also that TRPV2 may constitute a viable, new drug target.

Enhanced total neurite outgrowth and secondary branching in dorsal root ganglion neurons elicited by low intensity pulsed ultrasound.

PubMed

Ventre, Daniel; Puzan, Marissa; Ashbolt, Emily; Koppes, Abigail

2018-04-17

Despite the prevalence of peripheral nerve injuries (PNI), challenges remain in restoring full functionality to those afflicted. For recovery to occur, axons must extend across the injury site to connect with distal targets, where injury gap size is a critical factor in the probability of restoration of function. Current clinical therapies often achieve limited neural regeneration, motivating the development of new therapeutic interventions such as biophysical stimulation. To investigate the potential for low intensity, pulsed ultrasonic simulation (LIPUS) to impact peripheral nerve regeneration, primary neonatal rat dorsal root ganglion neurons were examined in vitro in response to ultrasound (US). Dissociated neurons were stimulated with varied acoustic power (low, medium, high) and their morphometrics, including total outgrowth, branching, and length, were analyzed acutely after 18 h of growth. Results show US increases total neurite outgrowth by 2.83-fold compared to unstimulated controls at the highest power. Neurite branching at medium and high-power US increased approximately 2-fold compared to controls, while low stimulation exhibited more muted trends. Neurite branching is also impacted by US, with medium and high power eliciting the highest branching, of approximately 2-fold compared to low power and unstimulated controls. These results demonstrate that US stimulation of DRG neurons in vitro impacts neurite morphology and enhances total extension, indicating the potential for advancing and understanding driving mechanisms of ultrasonic therapies for peripheral nerve regeneration.

The transcription factor C/EBPβ in the dorsal root ganglion contributes to peripheral nerve trauma–induced nociceptive hypersensitivity

PubMed Central

Li, Zhisong; Mao, Yuanyuan; Liang, Lingli; Wu, Shaogen; Yuan, Jingjing; Mo, Kai; Cai, Weihua; Mao, Qingxiang; Cao, Jing; Bekker, Alex; Zhang, Wei; Tao, Yuan-Xiang

2017-01-01

Changes in gene transcription in the dorsal root ganglion (DRG) after nerve trauma contribute to the genesis of neuropathic pain. We report that peripheral nerve trauma caused by chronic constriction injury (CCI) increased the abundance of the transcription factor C/EBPβ (CCAAT/enhancer binding protein β) in the DRG. Blocking this increase mitigated the development and maintenance of CCI-induced mechanical, thermal, and cold pain hypersensitivities without affecting basal responses to acute pain and locomotor activity. Conversely, mimicking this increase produced hypersensitivity to mechanical, thermal, or cold pain. In the ipsilateral DRG, C/EBPβ promoted a decrease in the abundance of the voltage-gated potassium channel subunit Kv1.2 and µ opioid receptor (MOR) at the mRNA and protein levels, which would be predicted to increase excitability in the ipsilateral DRG neurons and reduce the efficacy of morphine analgesia. These effects required C/EPBβ-mediated transcriptional activation of Ehmt2 (euchromatic histonelysine N-methyltransferase 2), which encodes G9a, an epigenetic silencer of the genes encoding Kv1.2 and MOR. Blocking the increase in C/EBPβ in the DRG improved morphine analgesia after CCI. These results suggest that C/EBPβ is an endogenous initiator of neuropathic pain and could be a potential target for the prevention and treatment of this disorder. PMID:28698219

Creating a Strain Relief Loop during S1 Transforaminal Lead Placement for Dorsal Root Ganglion Stimulation for Foot Pain: A Technical Note.

PubMed

van Velsen, Valery; van Helmond, Noud; Chapman, Kenneth B

2018-04-01

Chronic neuropathic pain is often refractory to conventional medical treatments and leads to significant disability and socio-economic burden. Dorsal root ganglion (DRG) stimulation has recently emerged as a treatment for persistent neuropathic pain, but creating a strain relief loop at the S1 level has thus far been a challenging technical component of DRG lead placement. We describe a refined technique for strain relief loop formation at the S1 level using a transforaminal approach that we employed in a 45-year-old patient with intractable foot pain. We successfully placed a strain relief loop in the sacral space in a predictable and easily reproducible manner using a transforaminal anchorless approach. The patient experienced a decrease in visual analog pain score (85%), and improvement in function during the trial period, and proceeded with permanent implantation. The described sacral transforaminal strain relief loop formation technique appears to be a more reliable and predictable technique of DRG lead placement in the sacrum than those previously documented. © 2017 World Institute of Pain.

Cortical-basal ganglionic degeneration.

PubMed

Riley, D E; Lang, A E; Lewis, A; Resch, L; Ashby, P; Hornykiewicz, O; Black, S

1990-08-01

We report our experience with 15 patients believed to have cortical-basal ganglionic degeneration. The clinical picture is distinctive, comprising features referable to both cortical and basal ganglionic dysfunction. Characteristic manifestations include cortical sensory loss, focal reflex myoclonus, "alien limb" phenomena, apraxia, rigidity and akinesia, a postural-action tremor, limb dystonia, hyperreflexia, and postural instability. The asymmetry of symptoms and signs is often striking. Brain imaging may demonstrate greater abnormalities contralateral to the more affected side. Postmortem studies in 2 patients revealed the characteristic pathologic features of swollen, poorly staining (achromatic) neurons and degeneration of cerebral cortex and substantia nigra. Biochemical analysis of 1 brain showed a severe, diffuse loss of dopamine in the striatum. This condition is more frequent than previously believed, and the diagnosis can be predicted during life on the basis of clinical findings. However, as with other "degenerative" diseases of the nervous system, a definitive diagnosis of cortical-basal ganglionic degeneration requires confirmation by autopsy.

PKCɛ mediates substance P inhibition of GABAA receptors-mediated current in rat dorsal root ganglion.

PubMed

Li, Li; Zhao, Lei; Wang, Yang; Ma, Ke-tao; Shi, Wen-yan; Wang, Ying-zi; Si, Jun-qiang

2015-02-01

The mechanism underlying the modulatory effect of substance P (SP) on GABA-activated response in rat dorsal root ganglion (DRG) neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA (1-1000 μmol/L) induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons (89.8 %) examined with whole-cell patch-clamp recordings. Bath application of GABA (1-1000 μmol/L) evoked a depolarizing response in 236 out of 257 (91.8%) DRG neurons examined with intracellular recordings. Application of SP (0.001-1 μmol/L) suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1 (NK1) receptors antagonist spantide but not by L659187 and SR142801 (1 μmol/L, n=7), selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C (PLC) inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKCε inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca²⁺-PKCε cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the "pre-synaptic inhibition" evoked by GABA, which may explain its role in pain and neurogenic inflammation.

Mechanical compression insults induce nanoscale changes of membrane-skeleton arrangement which could cause apoptosis and necrosis in dorsal root ganglion neurons.

PubMed

Quan, Xin; Guo, Kai; Wang, Yuqing; Huang, Liangliang; Chen, Beiyu; Ye, Zhengxu; Luo, Zhuojing

2014-01-01

In a primary spinal cord injury, the amount of mechanical compression insult that the neurons experience is one of the most critical factors in determining the extent of the injury. The ultrastructural changes that neurons undergo when subjected to mechanical compression are largely unknown. In the present study, using a compression-driven instrument that can simulate mechanical compression insult, we applied mechanical compression stimulation at 0.3, 0.5, and 0.7 MPa to dorsal root ganglion (DRG) neurons for 10 min. Combined with atomic force microscopy, we investigated nanoscale changes in the membrane-skeleton, cytoskeleton alterations, and apoptosis induced by mechanical compression injury. The results indicated that mechanical compression injury leads to rearrangement of the membrane-skeleton compared with the control group. In addition, mechanical compression stimulation induced apoptosis and necrosis and also changed the distribution of the cytoskeleton in DRG neurons. Thus, the membrane-skeleton may play an important role in the response to mechanical insults in DRG neurons. Moreover, sudden insults caused by high mechanical compression, which is most likely conducted by the membrane-skeleton, may induce necrosis, apoptosis, and cytoskeletal alterations.

Pyruvate Dehydrogenase Kinase-mediated Glycolytic Metabolic Shift in the Dorsal Root Ganglion Drives Painful Diabetic Neuropathy*

PubMed Central

Rahman, Md Habibur; Jha, Mithilesh Kumar; Kim, Jong-Heon; Nam, Youngpyo; Lee, Maan Gee; Go, Younghoon; Harris, Robert A.; Park, Dong Ho; Kook, Hyun; Lee, In-Kyu; Suk, Kyoungho

2016-01-01

The dorsal root ganglion (DRG) is a highly vulnerable site in diabetic neuropathy. Under diabetic conditions, the DRG is subjected to tissue ischemia or lower ambient oxygen tension that leads to aberrant metabolic functions. Metabolic dysfunctions have been documented to play a crucial role in the pathogenesis of diverse pain hypersensitivities. However, the contribution of diabetes-induced metabolic dysfunctions in the DRG to the pathogenesis of painful diabetic neuropathy remains ill-explored. In this study, we report that pyruvate dehydrogenase kinases (PDK2 and PDK4), key regulatory enzymes in glucose metabolism, mediate glycolytic metabolic shift in the DRG leading to painful diabetic neuropathy. Streptozotocin-induced diabetes substantially enhanced the expression and activity of the PDKs in the DRG, and the genetic ablation of Pdk2 and Pdk4 attenuated the hyperglycemia-induced pain hypersensitivity. Mechanistically, Pdk2/4 deficiency inhibited the diabetes-induced lactate surge, expression of pain-related ion channels, activation of satellite glial cells, and infiltration of macrophages in the DRG, in addition to reducing central sensitization and neuroinflammation hallmarks in the spinal cord, which probably accounts for the attenuated pain hypersensitivity. Pdk2/4-deficient mice were partly resistant to the diabetes-induced loss of peripheral nerve structure and function. Furthermore, in the experiments using DRG neuron cultures, lactic acid treatment enhanced the expression of the ion channels and compromised cell viability. Finally, the pharmacological inhibition of DRG PDKs or lactic acid production substantially attenuated diabetes-induced pain hypersensitivity. Taken together, PDK2/4 induction and the subsequent lactate surge induce the metabolic shift in the diabetic DRG, thereby contributing to the pathogenesis of painful diabetic neuropathy. PMID:26769971

The role of calcium in the desensitization of capsaicin responses in rat dorsal root ganglion neurons.

PubMed

Koplas, P A; Rosenberg, R L; Oxford, G S

1997-05-15

Capsaicin (Cap) is a pungent extract of the Capsicum pepper family, which activates nociceptive primary sensory neurons. Inward current and membrane potential responses of cultured neonatal rat dorsal root ganglion neurons to capsaicin were examined using whole-cell and perforated patch recording methods. The responses exhibited strong desensitization operationally classified as acute (diminished response during constant Cap exposure) and tachyphylaxis (diminished response to successive applications of Cap). Both acute desensitization and tachyphylaxis were greatly diminished by reductions in external Ca2+ concentration. Furthermore, chelation of intracellular Ca2+ by addition of either EGTA or bis(2-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid to the patch pipette attenuated both forms of desensitization even in normal Ca2+. Release of intracellular Ca2+ by caffeine triggered acute desensitization in the absence of extracellular Ca2+, and barium was found to effectively substitute for calcium in supporting desensitization. Cap activated inward current at an ED50 of 728 nM, exhibiting cooperativity (Hill coefficient, 2.2); however, both forms of desensitization were only weakly dependent on [Cap], suggesting a dissociation between activation of Cap-sensitive channels and desensitization. Removal of ATP and GTP from the intracellular solutions resulted in nearly complete tachyphylaxis even with intracellular Ca2+ buffered to low levels, whereas changes in nucleotide levels did not significantly alter the acute form of desensitization. These data suggest a key role for intracellular Ca2+ in desensitization of Cap responses, perhaps through Ca2+-dependent dephosphorylation at a locus that normally sustains Cap responsiveness via ATP-dependent phosphorylation. It also seems that the signaling mechanisms underlying the two forms of desensitization are not identical in detail.

Simultaneous cell death in the trigeminal ganglion and in ganglion neurons present in the oculomotor nerve of the bovine fetus.

PubMed Central

Bortolami, R; Lucchi, M L; Callegari, E; Barazzoni, A M; Costerbosa, G L; Scapolo, P A

1990-01-01

A well-developed ganglion and scattered ganglion cells are present in the intracranial portion of the oculomotor nerve during the first half of fetal life in the ox. In the second half of fetal life a dramatic reduction of the ganglion cells associated with the oculomotor nerve occurs because of spontaneous cell death. Concomitantly, the same phenomenon of cell death is found in the trigeminal ganglion, especially in its rostromedial portion. Free degenerating perikarya can be found in the cavernous sinus. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 PMID:2384329

Accumulation of misfolded SOD1 in dorsal root ganglion degenerating proprioceptive sensory neurons of transgenic mice with amyotrophic lateral sclerosis.

PubMed

Sábado, Javier; Casanovas, Anna; Tarabal, Olga; Hereu, Marta; Piedrafita, Lídia; Calderó, Jordi; Esquerda, Josep E

2014-01-01

Amyotrophic lateral sclerosis (ALS) is an adult-onset progressive neurodegenerative disease affecting upper and lower motoneurons (MNs). Although the motor phenotype is a hallmark for ALS, there is increasing evidence that systems other than the efferent MN system can be involved. Mutations of superoxide dismutase 1 (SOD1) gene cause a proportion of familial forms of this disease. Misfolding and aggregation of mutant SOD1 exert neurotoxicity in a noncell autonomous manner, as evidenced in studies using transgenic mouse models. Here, we used the SOD1(G93A) mouse model for ALS to detect, by means of conformational-specific anti-SOD1 antibodies, whether misfolded SOD1-mediated neurotoxicity extended to neuronal types other than MNs. We report that large dorsal root ganglion (DRG) proprioceptive neurons accumulate misfolded SOD1 and suffer a degenerative process involving the inflammatory recruitment of macrophagic cells. Degenerating sensory axons were also detected in association with activated microglial cells in the spinal cord dorsal horn of diseased animals. As large proprioceptive DRG neurons project monosynaptically to ventral horn MNs, we hypothesise that a prion-like mechanism may be responsible for the transsynaptic propagation of SOD1 misfolding from ventral horn MNs to DRG sensory neurons.

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

PubMed Central

Shi, Haohong; Luo, Xingjing

2016-01-01

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

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

PubMed

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

2016-05-01

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

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

TRPV1 Channels Are Functionally Coupled with BK(mSlo1) Channels in Rat Dorsal Root Ganglion (DRG) Neurons

PubMed Central

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 (Ca2+). 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 Ca2+ 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

Tumor necrosis factor-α-dependent infiltration of macrophages into the dorsal root ganglion in a rat disc herniation model.

PubMed

You, Changcheng; Zhu, Kai; Liu, Xiaoqi; Xi, Chunyang; Zhang, Zhipeng; Xu, Gongping; Yan, Jinglong

2013-11-01

A prospective molecular mechanism of macrophages infiltration in experimental disc herniation. To investigate the mechanisms of macrophages infiltration into the dorsal root ganglion (DRG) in a rat model of disc herniation. Macrophages infiltrate the DRG after application of nucleus pulposus (NP) on the DRG, and may play an important role in radiculopathy. However, the mechanisms of macrophages infiltration after NP application remain poorly understood. After experimental disc herniation in this study, we investigated changes in the expression of ED1 (a marker of macrophages) and vascular cell adhesion molecule-1 (VCAM-1) in DRG using immunofluorescence. We also investigated the expression of ED1 and VCAM-1 in DRG by treatment with tumor necrosis factor-α (TNF-α) inhibitor at the time of surgery. We found a massive ED1-positive macrophages infiltrated the DRG, and VCAM-1-like immunoreactivity vessels became evident after NP application. Furthermore, both macrophage infiltration and VCAM-1 expression were prevented by treatment with TNF-α inhibitor at the time of surgery. These findings indicated that macrophages infiltration into the DRG was TNF-α-dependent, and might be partly mediated by VCAM-1 in the early stage of experimental lumbar disc herination. Taken together, this study provides important preliminary data suggesting that TNF-α plays an important role in the macrophage infiltration. N/A.

Evaluation of poly(3,4-ethylenedioxythiophene)/carbon nanotube neural electrode coatings for stimulation in the dorsal root ganglion

PubMed Central

Kolarcik, Christi L.; Catt, Kasey; Rost, Erika; Albrecht, Ingrid N.; Bourbeau, Dennis; Du, Zhanhong; Kozai, Takashi D.Y.; Luo, Xiliang; Weber, Douglas J.; Cui, X. Tracy

2015-01-01

Objective The dorsal root ganglion (DRG) is an attractive target for implanting neural electrode arrays that restore sensory function or provide therapy via stimulation. However, penetrating microelectrodes designed for these applications are small and deliver low currents. For long-term performance of microstimulation devices, novel coating materials are needed in part to decrease impedance values at the electrode-tissue interface and to increase charge storage capacity. Approach Conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and multiwall carbon nanotubes (CNTs) were coated on the electrode surface and doped with the anti-inflammatory drug, dexamethasone. Electrode characteristics and the tissue reaction around neural electrodes as the result of stimulation, coating and drug release were characterized. Hematoxylin and eosin staining along with antibodies recognizing Iba1 (microglia/macrophages), NF200 (neuronal axons), NeuN (neurons), vimentin (fibroblasts), caspase-3 (cell death) and L1 (neural cell adhesion molecule) were used. Quantitative image analyses were performed using MATLAB. Main Results Our results indicate that coated microelectrodes have lower in vitro and in vivo impedance values. Significantly less neuronal death/damage was observed with coated electrodes as compared to non-coated controls. The inflammatory response with the PEDOT/CNT-coated electrodes was also reduced. Significance This study is the first to report on the utility of these coatings in stimulation applications. Our results indicate PEDOT/CNT coatings may be valuable additions to implantable electrodes used as therapeutic modalities. PMID:25485675

Evaluation of poly(3,4-ethylenedioxythiophene)/carbon nanotube neural electrode coatings for stimulation in the dorsal root ganglion

NASA Astrophysics Data System (ADS)

Kolarcik, Christi L.; Catt, Kasey; Rost, Erika; Albrecht, Ingrid N.; Bourbeau, Dennis; Du, Zhanhong; Kozai, Takashi D. Y.; Luo, Xiliang; Weber, Douglas J.; Cui, X. Tracy

2015-02-01

Objective. The dorsal root ganglion is an attractive target for implanting neural electrode arrays that restore sensory function or provide therapy via stimulation. However, penetrating microelectrodes designed for these applications are small and deliver low currents. For long-term performance of microstimulation devices, novel coating materials are needed in part to decrease impedance values at the electrode-tissue interface and to increase charge storage capacity. Approach. Conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) and multi-wall carbon nanotubes (CNTs) were coated on the electrode surface and doped with the anti-inflammatory drug, dexamethasone. Electrode characteristics and the tissue reaction around neural electrodes as a result of stimulation, coating and drug release were characterized. Hematoxylin and eosin staining along with antibodies recognizing Iba1 (microglia/macrophages), NF200 (neuronal axons), NeuN (neurons), vimentin (fibroblasts), caspase-3 (cell death) and L1 (neural cell adhesion molecule) were used. Quantitative image analyses were performed using MATLAB. Main results. Our results indicate that coated microelectrodes have lower in vitro and in vivo impedance values. Significantly less neuronal death/damage was observed with coated electrodes as compared to non-coated controls. The inflammatory response with the PEDOT/CNT-coated electrodes was also reduced. Significance. This study is the first to report on the utility of these coatings in stimulation applications. Our results indicate PEDOT/CNT coatings may be valuable additions to implantable electrodes used as therapeutic modalities.

Reactive species modify NaV1.8 channels and affect action potentials in murine dorsal root ganglion neurons.

PubMed

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

2016-01-01

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

Vascular Leiomyoma and Geniculate Ganglion

PubMed Central

Magliulo, Giuseppe; Iannella, Giannicola; Valente, Michele; Greco, Antonio; Appiani, Mario Ciniglio

2013-01-01

Objectives Discussion of a rare case of angioleiomyoma involving the geniculate ganglion and the intratemporal facial nerve segment and its surgical treatment. Design Case report. Setting Presence of an expansive lesion englobing the geniculate ganglion without any lesion to the cerebellopontine angle. Participants A 45-year-old man with a grade III facial paralysis according to the House-Brackmann scale of evaluation. Main Outcomes Measure Surgical pathology, radiologic appearance, histological features, and postoperative facial function. Results Removal of the entire lesion was achieved, preserving the anatomic integrity of the nerve; no nerve graft was necessary. Postoperative histology and immunohistochemical studies revealed features indicative of solid vascular leiomyoma. Conclusion Angioleiomyoma should be considered in the differential diagnosis of geniculate ganglion lesions. Optimal postoperative facial function is possible only by preserving the anatomical and functional integrity of the facial nerve. PMID:23943721

Grasses suppress shoot-borne roots to conserve water during drought

USDA-ARS?s Scientific Manuscript database

Many important crops are members of the Poaceae family, and develop fibrous root systems characterized by a high-degree of root initiation from the basal nodes of the shoot, termed the crown. While this post-embryonic shoot-borne root system represents the major conduit for water uptake, little is k...

Effects of nifedipine and captopril on vascular capacitance of ganglion-blocked anesthetized dogs.

PubMed

Ogilvie, R I; Zborowska-Sluis, D

1990-03-01

The hemodynamic effects of nifedipine and captopril at doses producing similar reductions in arterial pressure were studied in pentobarbital-anesthetized ventilated dogs after splenectomy during ganglion blockade with hexamethonium. Mean circulatory filling pressure (Pmcf) was determined during transient circulatory arrest induced by acetylcholine at baseline circulating blood volumes and after increases of 5 and 10 mL/kg. Central blood volumes (pulmonary artery to aortic root) were determined from transit times, and separately determined cardiac outputs (right atrium to pulmonary artery) were estimated by thermodilution. Nifedipine (n = 5) increased Pmcf at all circulating blood volumes and reduced total vascular capacitance without a change in total vascular compliance. Central blood volume, right atrial pressure, and cardiac output were increased with induced increases in circulating blood volume. In contrast, captopril (n = 5) did not alter total vascular capacitance, central blood volume, right atrial pressure, or cardiac output at baseline or with increased circulating volume. Thus, at doses producing similar reductions in arterial pressure, nifedipine but not captopril increased venous return and cardiac output in ganglion-blocked dogs.

Hmx1 is required for the normal development of somatosensory neurons in the geniculate ganglion

PubMed Central

Quina, Lely A.; Tempest, Lynne; Hsu, Yun-Wei A.; Cox, Timothy C.; Turner, Eric E.

2012-01-01

Hmx1 is a variant homeodomain transcription factor expressed in the developing sensory nervous system, retina, and craniofacial mesenchyme. Recently, mutations at the Hmx1 locus have been linked to craniofacial defects in humans, rats, and mice, but its role in nervous system development is largely unknown. Here we show that Hmx1 is expressed in a subset of sensory neurons in the cranial and dorsal root ganglia which does not correspond to any specific sensory modality. Sensory neurons in the dorsal root and trigeminal ganglia of Hmx1dm/dm mouse embryos have no detectable Hmx1 protein, yet they undergo neurogenesis and express sensory subtype markers normally, demonstrating that Hmx1 is not globally required for the specification of sensory neurons from neural crest precursors. Loss of Hmx1 expression has no obvious effect on the early development of the trigeminal (V), superior (IX/X), or dorsal root ganglia neurons in which it is expressed, but results in marked defects in the geniculate (VII) ganglion. Hmx1dm/dm mouse embryos possess only a vestigial posterior auricular nerve, and general somatosensory neurons in the geniculate ganglion are greatly reduced by mid-gestation. Although Hmx1 is expressed in geniculate neurons prior to cell cycle exit, it does not appear to be required for neurogenesis, and the loss of geniculate neurons is likely to be the result of increased cell death. Fate mapping of neural crest-derived tissues indicates that Hmx1-expressing somatosensory neurons at different axial levels may be derived from either the neural crest or the neurogenic placodes. PMID:22586713

Short-wavelength cone-opponent retinal ganglion cells in mammals.

PubMed

Marshak, David W; Mills, Stephen L

2014-03-01

In all of the mammalian species studied to date, the short-wavelength-sensitive (S) cones and the S-cone bipolar cells that receive their input are very similar, but the retinal ganglion cells that receive synapses from the S-cone bipolar cells appear to be quite different. Here, we review the literature on mammalian retinal ganglion cells that respond selectively to stimulation of S-cones and respond with opposite polarity to longer wavelength stimuli. There are at least three basic mechanisms to generate these color-opponent responses, including: (1) opponency is generated in the outer plexiform layer by horizontal cells and is conveyed to the ganglion cells via S-cone bipolar cells, (2) inputs from bipolar cells with different cone inputs and opposite response polarity converge directly on the ganglion cells, and (3) inputs from S-cone bipolar cells are inverted by S-cone amacrine cells. These are not mutually exclusive; some mammalian ganglion cells that respond selectively to S-cone stimulation seem to utilize at least two of them. Based on these findings, we suggest that the small bistratified ganglion cells described in primates are not the ancestral type, as proposed previously. Instead, the known types of ganglion cells in this pathway evolved from monostratified ancestral types and became bistratified in some mammalian lineages.

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

Auxins differentially regulate root system architecture and cell cycle protein levels in maize seedlings.

PubMed

Martínez-de la Cruz, Enrique; García-Ramírez, Elpidio; Vázquez-Ramos, Jorge M; Reyes de la Cruz, Homero; López-Bucio, José

2015-03-15

Maize (Zea mays) root system architecture has a complex organization, with adventitious and lateral roots determining its overall absorptive capacity. To generate basic information about the earlier stages of root development, we compared the post-embryonic growth of maize seedlings germinated in water-embedded cotton beds with that of plants obtained from embryonic axes cultivated in liquid medium. In addition, the effect of four different auxins, namely indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), indole-3-butyric acid (IBA) and 2,4-dichlorophenoxyacetic acid (2,4-D) on root architecture and levels of the heat shock protein HSP101 and the cell cycle proteins CKS1, CYCA1 and CDKA1 were analyzed. Our data show that during the first days after germination, maize seedlings develop several root types with a simultaneous and/or continuous growth. The post-embryonic root development started with the formation of the primary root (PR) and seminal scutellar roots (SSR) and then continued with the formation of adventitious crown roots (CR), brace roots (BR) and lateral roots (LR). Auxins affected root architecture in a dose-response fashion; whereas NAA and IBA mostly stimulated crown root formation, 2,4-D showed a strong repressing effect on growth. The levels of HSP101, CKS1, CYCA1 and CDKA in root and leaf tissues were differentially affected by auxins and interestingly, HSP101 registered an auxin-inducible and root specific expression pattern. Taken together, our results show the timing of early branching patterns of maize and indicate that auxins regulate root development likely through modulation of the HSP101 and cell cycle proteins. Copyright © 2014 Elsevier GmbH. All rights reserved.

Immunoglobulinfree light chains reduce in an antigen-specific manner the rate of rise of action potentials of mouse non-nociceptive dorsal root ganglion neurons.

PubMed

Rijnierse, Anneke; Kraneveld, Aletta D; Salemi, Arezo; Zwaneveld, Sandra; Goumans, Aleida P H; Rychter, Jakub W; Thio, Marco; Redegeld, Frank A; Westerink, Remco H S; Kroese, Alfons B A

2013-11-15

Plasma B cells secrete immunoglobulinfree light chains (IgLC) which by binding to mast cells can mediate hypersensitivity responses and are involved in several immunological disorders. To investigate the effects of antigen-specific IgLC activation, intracellular recordings were made from cultured murine dorsal root ganglion (DRG) neurons, which can specifically bind IgLC. The neurons were sensitized with IgLC for 90min and subsequently activated by application of the corresponding antigen (DNP-HSA). Antigen application induced a decrease in the rate of rise of the action potentials of non-nociceptive neurons (MANOVA, p=2.10(-6)), without affecting the resting membrane potential or firing threshold. The action potentials of the nociceptive neurons (p=0.57) and the electrical excitability of both types of neurons (p>0.35) were not affected. We conclude that IgLC can mediate antigen-specific responses by reducing the rate of rise of action potentials in non-nociceptive murine DRG neurons. We suggest that antigen-specific activation of IgLC-sensitized non-nociceptive DRG neurons may contribute to immunological hypersensitivity responses and neuroinflammation. © 2013.

Upregulation of nuclear factor‑κB and acid sensing ion channel 3 in dorsal root ganglion following application of nucleus pulposus onto the nerve root in rats.

PubMed

Wang, Dong; Pan, Hao; Zhu, Hang; Zhu, Li; He, Yong-Jiang; Wang, Jian; Jia, Gao-Yong

2017-10-01

The nucleus pulposus (NP) is an avascular, hydrated tissue that permits the intervertebral disc to resist compressive loads to the spine. To determine the mechanisms by which intervertebral disc degeneration is caused by the nucleus pulposus, the expression and regulation of nuclear factor (NF)‑κB and acid sensing ion channel 3 (ASIC3) were examined. For the intervertebral disc degeneration model, NP was harvested from the tail of rats and applied to the L5 dorsal root ganglion (DRG). The mechanical pain withdrawal threshold (PWT) in NP model rats was assessed. Reverse transcription‑quantitative polymerase chain reaction and western blotting were used to examine NF‑κB and ASIC3 expression levels in DRG. Finally, the effect of the NF‑κB inhibitor pyrrolidine dithiocarbamate (PDTC) and the ASIC3 signaling pathway blocker amiloride were examined. Rats exposed to NP exhibited decreased PWT for 12 days, and NF‑κB and ASIC3 was upregulated in DRG induced by NP 14 days after surgery. After administration of amiloride and PDTC to DRG affected by NP, the levels of nitric oxide (NO), tumor necrosis factor‑α (TNF‑α), interleukin‑6 (IL‑6), NF‑κB and ASIC3 were downregulated, and the levels of aquaporin (AQP) 1 and AQP3 were significantly increased for 14 days. In conclusion, these results suggested that NF‑κB and ASIC3 may serve an important role in intervertebral disc degeneration caused by NP.

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

PubMed

Menon-Johansson, A S; Berrow, N; Dolphin, A C

1993-11-01

High-voltage-activated (HVA) calcium channel currents (IBa) were recorded from acutely replated cultured dorsal root ganglion (DRG) neurons. IBa was irreversibly inhibited by 56.9 +/- 2.7% by 1 microM omega-conotoxin-GVIA (omega-CTx-GVIA), whereas the 1,4-dihydropyridine antagonist nicardipine was ineffective. The selective gamma-aminobutyric acidB (GABAB) agonist, (-)-baclofen (50 microM), inhibited the HVA IBa by 30.7 +/- 5.4%. Prior application of omega-CTx-GVIA completely occluded inhibition of the HVA IBa by (-)-baclofen, indicating that in this preparation (-)-baclofen inhibits N-type current. To investigate which G protein subtype was involved, cells were replated in the presence of anti-G protein antisera. Under these conditions the antibodies were shown to enter the cells through transient pores created during the replating procedure. Replating DRGs in the presence of anti-G(o) antiserum, raised against the C-terminal decapeptide of the G alpha o subunit, reduced (-)-baclofen inhibition of the HVA IBa, whereas replating DRGs in the presence of the anti-Gi antiserum did not. Using anti-G alpha o antisera (1:2000) and confocal laser microscopy, G alpha o localisation was investigated in both unreplated and replated neurons. G alpha o immunoreactivity was observed at the plasma membrane, neurites, attachment plaques and perinuclear region, and was particularly pronounced at points of cell-to-cell contact. The plasma membrane G alpha o immunoreactivity was completely blocked by preincubation with the immunising G alpha o undecapeptide (1 microgram.ml-1) for 1 h at 37 degrees C. A similar treatment also blocked recognition of G alpha o in brain membranes on immunoblots.(ABSTRACT TRUNCATED AT 250 WORDS)

Piriformis ganglion: An uncommon cause of sciatica.

PubMed

Park, J H; Jeong, H J; Shin, H K; Park, S J; Lee, J H; Kim, E

2016-04-01

Sciatica can occur due to a spinal lesion, intrapelvic tumor, diabetic neuropathy, and rarely piriformis syndrome. The causes of piriformis syndrome vary by a space-occupying lesion. A ganglionic cyst can occur in various lesions in the body but seldom around the hip joint. In addition, sciatica due to a ganglionic cyst around the hip joint has been reported in one patient in Korea who underwent surgical treatment. We experienced two cases of sciatica from a piriformis ganglionic cyst and we report the clinical characterics and progress after non-operative treatment by ultrasonography-guided aspiration. The two cases were diagnosed by magnetic resonance imaging and were treated by ultrasonography-guided aspiration. We followed the patients for more than 6months. The symptoms of piriformis syndrome from the ganglion improved following aspiration and this conservative treatment is a treatment method that can be used without extensive incision or cyst excision. Level IV historical case. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Upregulation of EMMPRIN (OX47) in Rat Dorsal Root Ganglion Contributes to the Development of Mechanical Allodynia after Nerve Injury.

PubMed

Wang, Qun; Sun, Yanyuan; Ren, Yingna; Gao, Yandong; Tian, Li; Liu, Yang; Pu, Yanan; Gou, Xingchun; Chen, Yanke; Lu, Yan

2015-01-01

Matrix metalloproteinases (MMPs) are widely implicated in inflammation and tissue remodeling associated with various neurodegenerative diseases and play an important role in nociception and allodynia. Extracellular Matrix Metalloproteinase Inducer (EMMPRIN) plays a key regulatory role for MMP activities. However, the role of EMMPRIN in the development of neuropathic pain is not clear. Western blotting, real-time quantitative RT-PCR (qRT-PCR), and immunofluorescence were performed to determine the changes of messenger RNA and protein of EMMPRIN/OX47 and their cellular localization in the rat dorsal root ganglion (DRG) after nerve injury. Paw withdrawal threshold test was examined to evaluate the pain behavior in spinal nerve ligation (SNL) model. The lentivirus containing OX47 shRNA was injected into the DRG one day before SNL. The expression level of both mRNA and protein of OX47 was markedly upregulated in ipsilateral DRG after SNL. OX47 was mainly expressed in the extracellular matrix of DRG. Administration of shRNA targeted against OX47 in vivo remarkably attenuated mechanical allodynia induced by SNL. In conclusion, peripheral nerve injury induced upregulation of OX47 in the extracellular matrix of DRG. RNA interference against OX47 significantly suppressed the expression of OX47 mRNA and the development of mechanical allodynia. The altered expression of OX47 may contribute to the development of neuropathic pain after nerve injury.

Radiotherapy Suppresses Bone Cancer Pain through Inhibiting Activation of cAMP Signaling in Rat Dorsal Root Ganglion and Spinal Cord.

PubMed

Zhu, Guiqin; Dong, Yanbin; He, Xueming; Zhao, Ping; Yang, Aixing; Zhou, Rubing; Ma, Jianhua; Xie, Zhong; Song, Xue-Jun

2016-01-01

Radiotherapy is one of the major clinical approaches for treatment of bone cancer pain. Activation of cAMP-PKA signaling pathway plays important roles in bone cancer pain. Here, we examined the effects of radiotherapy on bone cancer pain and accompanying abnormal activation of cAMP-PKA signaling. Female Sprague-Dawley rats were used and received tumor cell implantation (TCI) in rat tibia (TCI cancer pain model). Some of the rats that previously received TCI treatment were treated with X-ray radiation (radiotherapy). Thermal hyperalgesia and mechanical allodynia were measured and used for evaluating level of pain caused by TCI treatment. PKA mRNA expression in dorsal root ganglion (DRG) was detected by RT-PCR. Concentrations of cAMP, IL-1β, and TNF-α as well as PKA activity in DRG and the spinal cord were measured by ELISA. The results showed that radiotherapy significantly suppressed TCI-induced thermal hyperalgesia and mechanical allodynia. The level of PKA mRNA in DRG, cAMP concentration and PKA activity in DRG and in the spinal cord, and concentrations of IL-1β and TNF-α in the spinal cord were significantly reduced by radiotherapy. In addition, radiotherapy also reduced TCI-induced bone loss. These findings suggest that radiotherapy may suppress bone cancer pain through inhibition of activation of cAMP-PKA signaling pathway in DRG and the spinal cord.

Murine neural crest stem cells and embryonic stem cell-derived neuron precursors survive and differentiate after transplantation in a model of dorsal root avulsion.

PubMed

Konig, Niclas; Trolle, Carl; Kapuralin, Katarina; Adameyko, Igor; Mitrecic, Dinko; Aldskogius, Hakan; Shortland, Peter J; Kozlova, Elena N

2017-01-01

Spinal root avulsion results in paralysis and sensory loss, and is commonly associated with chronic pain. In addition to the failure of avulsed dorsal root axons to regenerate into the spinal cord, avulsion injury leads to extensive neuroinflammation and degeneration of second-order neurons in the dorsal horn. The ultimate objective in the treatment of this condition is to counteract degeneration of spinal cord neurons and to achieve functionally useful regeneration/reconnection of sensory neurons with spinal cord neurons. Here we compare survival and migration of murine boundary cap neural crest stem cells (bNCSCs) and embryonic stem cells (ESCs)-derived, predifferentiated neuron precursors after their implantation acutely at the junction between avulsed dorsal roots L3-L6 and the spinal cord. Both types of cells survived transplantation, but showed distinctly different modes of migration. Thus, bNCSCs migrated into the spinal cord, expressed glial markers and formed elongated tubes in the peripheral nervous system (PNS) compartment of the avulsed dorsal root transitional zone (DRTZ) area. In contrast, the ESC transplants remained at the site of implantation and differentiated to motor neurons and interneurons. These data show that both stem cell types successfully survived implantation to the acutely injured spinal cord and maintained their differentiation and migration potential. These data suggest that, depending on the source of neural stem cells, they can play different beneficial roles for recovery after dorsal root avulsion. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Incomplete segregation of endorgan-specific vestibular ganglion cells in mice and rats

NASA Technical Reports Server (NTRS)

Maklad, A.; Fritzsch, B.

1999-01-01

The endorgan-specific distribution of vestibular ganglion cells was studied in neonatal and postnatal rats and mice using indocarbocyanine dye (DiI) and dextran amines for retrograde and anterograde labeling. Retrograde DiI tracing from the anterior vertical canal labeled neurons scattered throughout the whole superior vestibular ganglion, with denser labeling at the dorsal and central regions. Horizontal canal neurons were scattered along the dorsoventral axis with more clustering toward the dorsal and ventral poles of this axis. Utricular ganglion cells occupied predominantly the central region of the superior vestibular ganglion. This utricular population overlapped with both the anterior vertical and horizontal canals' ganglion cells. Posterior vertical canal neurons were clustered in the posterior part of the inferior vestibular ganglion. The saccular neurons were distributed in the two parts of the vestibular ganglion, the superior and inferior ganglia. Within the inferior ganglion, the saccular neurons were clustered in the anterior part. In the superior ganglion, the saccular neurons were widely scattered throughout the whole ganglion with more numerous neurons at the posterior half. Small and large neurons were labeled from all endorgans. Examination of the fiber trajectory within the superior division of the vestibular nerve showed no clear lamination of the fibers innervating the different endorgans. These results demonstrate an overlapping pattern between the different populations within the superior ganglion, while in the inferior ganglion, the posterior canal and saccular neurons show tighter clustering but incomplete segregation. This distribution implies that the ganglion cells are assigned for their target during development in a stochastic rather than topographical fashion.

Shp-1 dephosphorylates TRPV1 in dorsal root ganglion neurons and alleviates CFA-induced inflammatory pain in rats.

PubMed

Xiao, Xing; Zhao, Xiao-Tao; Xu, Ling-Chi; Yue, Lu-Peng; Liu, Feng-Yu; Cai, Jie; Liao, Fei-Fei; Kong, Jin-Ge; Xing, Guo-Gang; Yi, Ming; Wan, You

2015-04-01

Transient receptor potential vanilloid 1 (TRPV1) receptors are expressed in nociceptive neurons of rat dorsal root ganglions (DRGs) and mediate inflammatory pain. Nonspecific inhibition of protein-tyrosine phosphatases (PTPs) increases the tyrosine phosphorylation of TRPV1 and sensitizes TRPV1. However, less is known about tyrosine phosphorylation's implication in inflammatory pain, compared with that of serine/threonine phosphorylation. Src homology 2 domain-containing tyrosine phosphatase 1 (Shp-1) is a key phosphatase dephosphorylating TRPV1. In this study, we reported that Shp-1 colocalized with and bound to TRPV1 in nociceptive DRG neurons. Shp-1 inhibitors, including sodium stibogluconate and PTP inhibitor III, sensitized TRPV1 in cultured DRG neurons. In naive rats, intrathecal injection of Shp-1 inhibitors increased both TRPV1 and tyrosine-phosphorylated TRPV1 in DRGs and induced thermal hyperalgesia, which was abolished by pretreatment with TRPV1 antagonists capsazepine, BCTC, or AMG9810. Complete Freund's adjuvant (CFA)-induced inflammatory pain in rats significantly increased the expression of Shp-1, TRPV1, and tyrosine-phosphorylated TRPV1, as well as the colocalization of Shp-1 and TRPV1 in DRGs. Intrathecal injection of sodium stibogluconate aggravated CFA-induced inflammatory pain, whereas Shp-1 overexpression in DRG neurons alleviated it. These results suggested that Shp-1 dephosphorylated and inhibited TRPV1 in DRG neurons, contributing to maintain thermal nociceptive thresholds in normal rats, and as a compensatory mechanism, Shp-1 increased in DRGs of rats with CFA-induced inflammatory pain, which was involved in protecting against excessive thermal hyperalgesia.

The expression of hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) and HCN2 in the rat trigeminal ganglion, sensory root, and dental pulp.

PubMed

Cho, Y S; Kim, Y S; Moozhayil, S J; Yang, E S; Bae, Y C

2015-04-16

Hyperpolarization-activated cyclic nucleotide-gated channel 1 (HCN1) and 2 (HCN2) are abundantly expressed in primary sensory neurons and contribute to neuronal excitability and pathological pain. We studied the expression of HCN1 and HCN2 in the rat trigeminal ganglion (TG) neurons and axons in the dental pulp, and the changes in their expression following inflammation, using light- and electron-microscopic immunocytochemistry and quantitative analysis. HCN1 and HCN2 were expressed predominantly in large-sized, neurofilament 200-immunopositive (+) or parvalbumin+ soma in the TG whereas they were expressed mostly in unmyelinated and small myelinated axons in the sensory root. The expression was particularly strong along the plasma membrane in the soma. In the dental pulp, majority of HCN1+ and HCN2+ axons coexpressed calcitonin gene-related peptide. They were expressed mainly in the peripheral pulp and pulp horn where the axons branch extensively in the dental pulp. The expression of HCN1 and HCN2 in TG neurons increased significantly in rats with experimentally induced inflammation of the dental pulp. Our findings support the notion that HCN1 and HCN2 are expressed mainly by both the soma of mechanosensitive neurons in the TG and peripheral axons of nociceptive neurons in the sensory root, and may play a role in the mechanisms of inflammatory pain from the dental pulp. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Complete adult neurogenesis within a Wallerian degenerating nerve expressed as an ectopic ganglion.

PubMed

Nakano, Tomonori; Kurimoto, Shigeru; Kato, Shuichi; Asano, Kenichi; Hirata, Takuma; Kiyama, Hiroshi; Hirata, Hitoshi

2018-06-01

Neurogenesis in the adult peripheral nervous system remains to be demonstrated. We transplanted embryonic neural stem cells into a Wallerian degenerating nerve graft and observed development of a nodular structure consisting of neurons, glia, and Schwann cells. Histological analysis revealed a structure loosely resembling the spinal cord, including a synaptic network that formed along the neuron. Furthermore, the new axons reinnervated the paralysed muscle, forming both de novo and revived neuromuscular junctions. Reinnervation of the paralysed muscle resulted in significantly greater mean wet muscle weight and muscle fibre cross-sectional area on the cell transplantation side than on the surgical control side (body weight 0.071 ± 0.011% vs. 0.051 ± 0.007%, p = .006; area 355.6 ± 345.2 vs. 114.0 ± 132.0 μm 2 , p < .001). Electrophysiological experiments demonstrated a functional connection between the neurons and muscle; hence, we identified this nodule as an ectopic ganglion. Surprisingly, in green rat experiments, most of these glial cells, but none of the neurons, expressed enhanced green fluorescent protein, suggesting that the cells constituting the ectopic ganglion were derived from both transplanted stem cells and endogenous stem cells. Such adult neurogenesis in a peripheral nerve related to neural stem cell transplantation has not been reported previously, and these results form the basis for a novel regenerative medicine approach in paralysed muscle. Copyright © 2018 John Wiley & Sons, Ltd.

Light-evoked currents in retinal ganglion cells from dystrophic RCS rats.

PubMed

Liu, Kang; Wang, Yi; Yin, Zhengqin; Weng, Chuanhuang

2013-01-01

To study the electrophysiological properties of the light-evoked currents in ganglion cells in situations of retinal degeneration. We investigated light-evoked currents in ganglion cells by performing whole-cell patch-clamp recordings from ganglion cells using a retina-stretched preparation from Royal College of Surgeons (RCS) rats, a model of retinal degeneration and congenic controls at different ages. Pharmacological inhibitors of the AMPA receptor (NBQX), GABA receptor (BMI), and sodium channels (TTX) were used to identify the components of the light-evoked currents in ON, OFF and ON-OFF retinal ganglion cells. We found that the light-evoked currents in ganglion cells from control rats were inhibited by NBQX, BMI and TTX, suggesting that AMPA receptors, GABA receptors and sodium channels contribute to these currents in ganglion cells. However, only AMPA receptor-mediated currents were recorded in RCS rats. Light-evoked inward currents were absent in the majority of ganglion cells from RCS rats, particularly at the later stages of retinal degeneration. At earlier stages of retinal degeneration, we found that both the timing and amplitude of light-evoked currents are significantly different in ganglion cells from RCS and control rats. Our study furthers the understanding of the electrophysiological characteristics of retinal ganglion cells during retinal degeneration, and provides insight into the optimal timing for the treatment of retinal degeneration. Copyright © 2013 S. Karger AG, Basel.

Abnormal neurofilament inclusions and segregations in dorsal root ganglia of a Charcot-Marie-Tooth type 2E mouse model.

PubMed

Zhao, Jian; Brown, Kristy; Liem, Ronald K H

2017-01-01

Charcot-Marie-Tooth (CMT) disease or hereditary motor and sensory neuropathy is the most prevalent inherited peripheral neuropathy and is associated with over 90 causative genes. Mutations in neurofilament light polypeptide gene, NEFL cause CMT2E, an axonal form of CMT that results in abnormal structures and/or functions of peripheral axons in spinal cord motor neurons and dorsal root ganglion neurons. We have previously generated and characterized a knock-in mouse model of CMT2E with the N98S mutation in Nefl that presented with multiple inclusions in spinal cord neurons. In this report, we conduct immunofluorescence studies of cultured dorsal root ganglia (DRG) from NeflN98S/+ mice, and show that inclusions found in DRG neurites can occur in embryonic stages. Ultrastructural analyses reveal that the inclusions are disordered neurofilaments packed in high density, segregated from other organelles. Immunochemical studies show decreased NFL protein levels in DRG, cerebellum and spinal cord in NeflN98S/+ mice, and total NFL protein pool is shifted toward the triton-insoluble fraction. Our findings reveal the nature of the inclusions in NeflN98S/+ mice, provide useful information to understand mechanisms of CMT2E disease, and identify DRG from NeflN98S/+ mice as a useful cell line model for therapeutic discoveries.

Developmental Profiling of Spiral Ganglion Neurons Reveals Insights into Auditory Circuit Assembly

PubMed Central

Lu, Cindy C.; Appler, Jessica M.; Houseman, E. Andres; Goodrich, Lisa V.

2011-01-01

The sense of hearing depends on the faithful transmission of sound information from the ear to the brain by spiral ganglion (SG) neurons. However, how SG neurons develop the connections and properties that underlie auditory processing is largely unknown. We catalogued gene expression in mouse SG neurons from embryonic day 12 (E12), when SG neurons first extend projections, up until postnatal day 15 (P15), after the onset of hearing. For comparison, we also analyzed the closely-related vestibular ganglion (VG). Gene ontology analysis confirmed enriched expression of genes associated with gene regulation and neurite outgrowth at early stages, with the SG and VG often expressing different members of the same gene family. At later stages, the neurons transcribe more genes related to mature function, and exhibit a dramatic increase in immune gene expression. Comparisons of the two populations revealed enhanced expression of TGFβ pathway components in SG neurons and established new markers that consistently distinguish auditory and vestibular neurons. Unexpectedly, we found that Gata3, a transcription factor commonly associated with auditory development, is also expressed in VG neurons at early stages. We therefore defined new cohorts of transcription factors and axon guidance molecules that are uniquely expressed in SG neurons and may drive auditory-specific aspects of their differentiation and wiring. We show that one of these molecules, the receptor guanylyl cyclase Npr2, is required for bifurcation of the SG central axon. Hence, our data set provides a useful resource for uncovering the molecular basis of specific auditory circuit assembly events. PMID:21795542

Effects of 14 days of spaceflight and nine days of recovery on cell body size and succinate dehydrogenase activity of rat dorsal root ganglion neurons

NASA Technical Reports Server (NTRS)

Ishihara, A.; Ohira, Y.; Roy, R. R.; Nagaoka, S.; Sekiguchi, C.; Hinds, W. E.; Edgerton, V. R.

1997-01-01

The cross-sectional areas and succinate dehydrogenase activities of L5 dorsal root ganglion neurons in rats were determined after 14 days of spaceflight and after nine days of recovery. The mean and distribution of the cross-sectional areas were similar to age-matched, ground-based controls for both the spaceflight and for the spaceflight plus recovery groups. The mean succinate dehydrogenase activity was significantly lower in spaceflight compared to aged-matched control rats, whereas the mean succinate dehydrogenase activity was similar in age-matched control and spaceflight plus recovery rats. The mean succinate dehydrogenase activity of neurons with cross-sectional areas between 1000 and 2000 microns2 was lower (between 7 and 10%) in both the spaceflight and the spaceflight plus recovery groups compared to the appropriate control groups. The reduction in the oxidative capacity of a subpopulation of sensory neurons having relatively large cross-sectional areas immediately following spaceflight and the sustained depression for nine days after returning to 1 g suggest that the 0 g environment induced significant alterations in proprioceptive function.

Up-Regulation of the Biosynthesis and Release of Substance P through Wnt/β-Catenin Signaling Pathway in Rat Dorsal Root Ganglion Cells.

PubMed

Li, Yu-Sang; Xi, Yang; Li, Xiao-Jun; Leng, Chang-Long; Jia, Mei-Mei; Zhang, Wei Kevin; Tang, He-Bin

2015-01-01

To examine regulatory effects of β-catenin on the biosynthesis and release of substance P, a rat chronic constriction injury (CCI) model and a rat dorsal root ganglion (DRG) cell culture model were used in the present study. The CCI treatment significantly induced the overall expression of β-catenin (158 ± 6% of sham) in the ipsilateral L5 DRGs in comparison with the sham group (109 ± 4% of sham). The CCI-induced aberrant expression of β-catenin was significantly attenuated by oral administration of diclofenac (119 ± 6% of the sham value; 10 mg/kg). Importantly, aberrant nuclear accumulation of β-catenin in cultured DRG cells resulted in up-regulation of the PPT-A mRNA expression and the substance P release. The up-regulation of both the PPT-A mRNA expression and the substance P release by either a GSK-3β inhibitor TWS119 (10 μM) or a Wnt signaling agonist Wnt-3a (100 ng/ml) were significantly abolished by an inhibitor of cyclooxygenase-2 (COX-2; NS-398, 1 μM). Collectively, these data suggest that nociceptive input-activated β-catenin signaling plays an important role in regulating the biosynthesis and release of substance P, which may contribute to the inflammation responses related to chronic pain.

The ciliary margin zone of the mammalian retina generates retinal ganglion cells

PubMed Central

Marcucci, Florencia; Murcia-Belmonte, Veronica; Coca, Yaiza; Ferreiro-Galve, Susana; Wang, Qing; Kuwajima, Takaaki; Khalid, Sania; Ross, M. Elizabeth; Herrera, Eloisa; Mason, Carol

2016-01-01

Summary The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live-imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. As Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2−/− mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2+ cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. PMID:28009286

The inhibitory effect of sacral dorsal root ganglion stimulation on nociceptive and nonnociceptive bladder reflexes in cats.

PubMed

Wang, Zhaoxia; Liao, Limin; Deng, Han; Li, Xing; Chen, Guoqing

2018-05-01

To investigate the inhibitory effects of electrical stimulation of sacral dorsal root ganglion (DRG) on bladder activity under non-nociceptive and nociceptive bladder conditions in cats. 12 cats were divided into non-nociceptive and nociceptive groups. Saline was used to distend the bladder and induce non-nociceptive bladder activity, while acetic acid (AA, 0.25%) was used to induce nociceptive bladder overactivity, S1 or S2 DRG stimulation was applied via a pair of hook electrodes placed in the right S1 and S2 DRG. In both non-nociceptive and nociceptive groups, stimulation at 3 and 5 Hz significantly increased bladder capacity (BC) and no significantly different between the two frequencies. In non-nociceptive group, S1 DRG stimulation at 3 Hz was as effective (increasing BC to 139.7 ± 5.6 and 166.9 ± 12.21% of control at 1T and 3/2T, respectively) as S2 DRG stimulation (increases BC to 129.2 ± 5.6 and 160.5 ± 13.3% of control). In nociceptive group, AA reduced the BC to 62.6 ± 11.7% of saline control. S1 DRG stimulation at 3 Hz was also as effective (increasing BC to 54.9 ± 5.5 and 61.9 ± 6.0% of saline control at 1T and 3/2T, respectively) as S2 DRG stimulation (increases BC to 58.3 ± 3.7 and 65.6 ± 3.7% of control). This study showed the effective inhibition on bladder activity under both non-nociceptive and nociceptive conditions, suggesting the possibility of sacral DRG stimulation to treat bladder overactivity.

Morphological patterns in children with ganglion related enteric neuronal abnormalities.

PubMed

Henna, Nausheen; Nagi, Abdul H; Sheikh, Muhammad A; Shaukat, Mahmood

2011-01-01

Hirschsprung's Disease (HD) is a developmental disorder of enteric nervous system characterised by the absence of ganglion cells in submucosal (Meissner's) and myenteric (Aurbach's) plexuses of distal bowel. The purpose of the present study was to observe and report the morphological patterns of ganglion related enteric neuronal abnormalities in children presented with clinical features of (HD) in a Pakistani population. A total of 92 patients with clinical presentation of HD were enrolled between March 2009 and October 2009. Among them, 8 were excluded according to the exclusion criteria. After detailed history and physical examination, paraffin embedded H and E stained sections were prepared from the serial open biopsies from colorectum. The data was analysed using SPSS-17. Frequencies and percentages are given for qualitative variables. Non-parametric Binomial Chi-Square test was applied to observe within group associations and p<0.05 was considered statistically significant. Among 84 patients, 13 (15.5%) proved to be normally ganglionic whereas 71 (84.5%) showed ganglion related enteric neuronal abnormalities namely isolated hypoganglionosis 9 (12.7%), immaturity of ganglion cells 9 (12.7%), isolated hyperganglionosis (IND Type B) 2 (2.8%) and Hirschsprung's disease 51 (71.8%). Among HD group, 34 (66.7%) belonged to isolated form and 17 (33.3%) showed combined ganglion related abnormalities. Hirschsprung's disease is common in Pakistani population, followed by hypoganglionosis, immaturity of ganglion cells and IND type B. The presence of hypertrophic nerve fibres was significant in HD, hyperganglionosis and hypoganglionosis, whereas, no hypertrophic nerve fibres were appreciated in immaturity of ganglion cell group.

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

PubMed

Cang, Chun-Lei; Zhang, Hua; Zhang, Yu-Qiu; Zhao, Zhi-Qi

2009-06-30

Substance P (SP), which mainly exists in a subtype of small-diameter dorsal root ganglion (DRG) neurons, is an important signal molecule in pain processing in the spinal cord. Our previous results have proved the expression of SP receptor neurokinin-1 (NK-1) on DRG neurons and its interaction with transient receptor potential vanilloid 1 (TRPV1) receptor. In this study we investigated the effect of NK-1 receptor agonist on Na(v)1.8, a tetrodotoxin (TTX)-resistant sodium channel, in rat small-diameter DRG neurons employing whole-cell patch clamp recordings. NK-1 agonist [Sar(9), Met(O2)(11)]-substance P (Sar-SP) significantly enhanced the Na(v)1.8 currents in a subgroup of small-diameter DRG neurons under both the normal and inflammatory situation, and the enhancement was blocked by NK-1 antagonist Win51708 and protein kinase C (PKC) inhibitor bisindolylmaleimide (BIM), but not the protein kinase A (PKA) inhibitor H89. In particular, the inhibitor of PKCepsilon, a PKC isoform, completely blocked this effect. Under current clamp model, Sar-SP reduced the amount of current required to evoke action potentials and increased the firing rate in a subgroup of DRG neurons. These data suggest that activation of NK-1 receptor potentiates Na(v)1.8 sodium current via PKCepsilon-dependent signaling pathway, probably participating in the generation of inflammatory hyperalgesia.

Quantitative Analysis of Rat Dorsal Root Ganglion Neurons Cultured on Microelectrode Arrays Based on Fluorescence Microscopy Image Processing.

PubMed

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

2015-12-01

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

Augmentation of glycolytic metabolism by meclizine is indispensable for protection of dorsal root ganglion neurons from hypoxia-induced mitochondrial compromise.

PubMed

Zhuo, Ming; Gorgun, Murat F; Englander, Ella W

2016-10-01

To meet energy demands, dorsal root ganglion (DRG) neurons harbor high mitochondrial content, which renders them acutely vulnerable to disruptions of energy homeostasis. While neurons typically rely on mitochondrial energy production and have not been associated with metabolic plasticity, new studies reveal that meclizine, a drug, recently linked to modulations of energy metabolism, protects neurons from insults that disrupt energy homeostasis. We show that meclizine rapidly enhances glycolysis in DRG neurons and that glycolytic metabolism is indispensable for meclizine-exerted protection of DRG neurons from hypoxic stress. We report that supplementation of meclizine during hypoxic exposure prevents ATP depletion, preserves NADPH and glutathione stores, curbs reactive oxygen species (ROS) and attenuates mitochondrial clustering in DRG neurites. Using extracellular flux analyzer, we show that in cultured DRG neurons meclizine mitigates hypoxia-induced loss of mitochondrial respiratory capacity. Respiratory capacity is a measure of mitochondrial fitness and cell ability to meet fluctuating energy demands and therefore, a key determinant of cellular fate. While meclizine is an 'old' drug with long record of clinical use, its ability to modulate energy metabolism has been uncovered only recently. Our findings documenting neuroprotection by meclizine in a setting of hypoxic stress reveal previously unappreciated metabolic plasticity of DRG neurons as well as potential for pharmacological harnessing of the newly discovered metabolic plasticity for protection of peripheral nervous system under mitochondria compromising conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Lack of body positional effects on paresthesias when stimulating the dorsal root ganglion (DRG) in the treatment of chronic pain.

PubMed

Kramer, Jeffery; Liem, Liong; Russo, Marc; Smet, Iris; Van Buyten, Jean-Pierre; Huygen, Frank

2015-01-01

One prominent side effect from neurostimulation techniques, and in particular spinal cord stimulation (SCS), is the change in intensity of stimulation when moving from an upright (vertical) to a recumbent or supine (horizontal) position and vice versa. It is well understood that the effects of gravity combined with highly conductive cerebrospinal fluid provide the mechanism by which changes in body position can alter the intensity of stimulation-induced paresthesias. While these effects are well established for leads that are placed within the more medial aspects of the spinal canal, little is known about these potential effects in leads placed in the lateral epidural space and in particular within the neural foramina near the dorsal root ganglion (DRG). We prospectively validated a newly developed paresthesia intensity rating scale and compared perceived paresthesia intensities when subjects assumed upright vs. supine bodily positions during neuromodulation of the DRG. On average, the correlation coefficient between stimulation intensity (pulse amplitude) and perceived paresthesia intensity was 0.83, demonstrating a strong linear relationship. No significant differences in paresthesia intensities were reported within subjects when moving from an upright (4.5 ± 0.14) to supine position 4.5 (± 0.12) (p > 0.05). This effect persisted through 12 months following implant. Neuromodulation of the DRG produces paresthesias that remain consistent across body positions, suggesting that this paradigm may be less susceptible to positional effects than dorsal column stimulation. © 2014 International Neuromodulation Society.

Identification of Key Pathways and Genes in L4 Dorsal Root Ganglion (DRG) After Sciatic Nerve Injury via Microarray Analysis.

PubMed

Zhao, He; Duan, Li-Jun; Sun, Qing-Ling; Gao, Yu-Shan; Yang, Yong-Dong; Tang, Xiang-Sheng; Zhao, Ding-Yan; Xiong, Yang; Hu, Zhen-Guo; Li, Chuan-Hong; Chen, Si-Xue; Liu, Tao; Yu, Xing

2018-04-19

Peripheral nerve injury (PNI) has devastating consequences. Dorsal root ganglion as a pivotal locus participates in the process of neuropathic pain and nerve regeneration. In recent years, gene sequencing technology has seen rapid rise in the biomedicine field. So, we attempt to gain insight into in the mechanism of neuropathic pain and nerve regeneration in the transcriptional level and to explore novel genes through bioinformatics analysis. The gene expression profiles of GSE96051 were downloaded from GEO database. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were performed, and protein-protein interaction (PPI) network of the differentially expressed genes (DEGs) was constructed by Cytoscape software. Our results showed that both IL-6 and Jun genes and the signaling pathway of MAPK, apoptosis, P53 present their vital modulatory role in nerve regeneration and neuropathic pain. Noteworthy, 13 hub genes associated with neuropathic pain and nerve regeneration, including Ccl12, Ppp1r15a, Cdkn1a, Atf3, Nts, Dusp1, Ccl7, Csf, Gadd45a, Serpine1, Timp1 were rarely reported in PubMed database, these genes may provide us the new orientation in experimental research and clinical study. Our results may provide more deep insight into the mechanism and a promising therapeutic target. The next step is to put our emphasis on an experiment level and to verify the novel genes from 13 hub genes.

Antidepressant Imipramine Protects Bupivacaine-Induced Neurotoxicity in Dorsal Root Ganglion Neurons Through Coactivation of TrkA and TrkB.

PubMed

Guo, Jianrong; Wang, Huan; Tao, Qiang; Sun, Shiyu; Liu, Li; Zhang, Jianping; Yang, Dawei

2017-11-01

In our work, we used an in vitro culture model to investigate whether antidepressant imipramine (Ip) may protect bupivacaine (Bv)-induced neurotoxicity in mouse dorsal root ganglion (DRG). Adult mouse DRG was treated with 5 mM Bv in vitro to induce neurotoxicity. DRG was then pre-treated with Ip, prior to Bv, to examine its effects on protecting Bv-induced DRG apoptosis and neurite degeneration. Ip-induced dynamic changes in Trk receptors, including TrkA/B/C and phosphor (p-)TrkA/B/C, were examined by qPCR and Western blot. TrkA and TrkB were inhibited by siRNAs to further investigate their functional role in Ip- and Bv-treated DRG. Ip protected Bv-induced apoptosis and neurite loss in DRG. Ip did not alter TrkA/B/C expressions, whereas significantly augmented protein productions of p-TrkA and p-TrkB, but not p-TrkC. SiRNA-mediated TrkA or TrkB downregulation inhibited Trk receptors, and reduced p-TrkA and p-TrkB in DRG. TrkA or TrkB downregulation alone had no effect on Ip-induced protection in Bv-injured DRG. However, co-inhibition of TrkA and TrkB significantly ameliorated the protective effect of Ip on Bv-induced apoptosis and neurite loss in DRG. Imipramine protected bupivacaine-induced neurotoxicity in DRG, likely via the co-activation of TrkA and TrkB signaling pathways. J. Cell. Biochem. 118: 3960-3967, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Depicting the pterygopalatine ganglion on 3 Tesla magnetic resonance images.

PubMed

Bratbak, Daniel Fossum; Folvik, Mari; Nordgård, Ståle; Stovner, Lars Jacob; Dodick, David W; Matharu, Manjit; Tronvik, Erling

2018-06-01

The pterygopalatine ganglion has yet not been identified on medical images in living humans. The primary aim of this study was to evaluate whether the pterygopalatine ganglion could be identified on 3 T MR imaging. This study was performed on medical images of 20 Caucasian subjects on both sides (n = 40 ganglia) with an exploratory design. 3 T MR images were assessed by two physicians for the presence and size of the pterygopalatine ganglion. The distance from the pterygopalatine ganglion to four bony landmarks was registered from fused MR and CT images. In an equivalence analysis, the distances were compared to those obtained in an anatomical cadaveric study serving as historical controls (n = 50). A structure assumed to be the pterygopalatine ganglion was identified on MR images in all patients on both sides by both physicians. The mean size was depth 2.1 ± 0.5 mm, width 4.2 ± 1.1 mm and height 5.1 ± 1.4 mm, which is in accordance with formerly published data. Equivalence of the measurements on MR images and the historical controls was established, suggesting that the structure identified on the MR images is the pterygopalatine ganglion. Our findings suggest that the pterygopalatine ganglion can be detected on 3 T MR images. Identification of the pterygopalatine ganglion may be important for image-guided interventions targeting the pterygopalatine ganglion, and has the potential to increase the efficacy, safety and reliability for these treatments.

In vitro formation of the Merkel cell-neurite complex in embryonic mouse whiskers using organotypic co-cultures.

PubMed

Ishida, Kentaro; Saito, Tetsuichiro; Mitsui, Toshiyuki

2018-06-01

A Merkel cell-neurite complex is a touch receptor composed of specialized epithelial cells named Merkel cells and peripheral sensory nerves in the skin. Merkel cells are found in touch-sensitive skin components including whisker follicles. The nerve fibers that innervate Merkel cells of a whisker follicle extend from the maxillary branch of the trigeminal ganglion. Whiskers as a sensory organ attribute to the complicated architecture of the Merkel cell-neurite complex, and therefore it is intriguing how the structure is formed. However, observing the dynamic process of the formation of a Merkel cell-neurite complex in whiskers during embryonic development is still difficult. In this study, we tried to develop an organotypic co-culture method of a whisker pad and a trigeminal ganglion explant to form the Merkel cell-neurite complex in vitro. We initially developed two distinct culture methods of a single whisker row and a trigeminal ganglion explant, and then combined them. By dissecting and cultivating a single row from a whisker pad, the morphogenesis of whisker follicles could be observed under a microscope. After the co-cultivation of the whisker row with a trigeminal ganglion explant, a Merkel cell-neurite complex composed of Merkel cells, which were positive for both cytokeratin 8 and SOX2, Neurofilament-H-positive trigeminal nerve fibers and Schwann cells expressing Nestin, SOX2 and SOX10 was observed via immunohistochemical analyses. These results suggest that the process for the formation of a Merkel cell-neurite complex can be observed under a microscope using our organotypic co-culture method. © 2018 Japanese Society of Developmental Biologists.

Improved rooting of western white pine shoots from tissue cultures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amerson, H.V.; Mott, R.L.

1982-01-01

Adventitious shoots of Pinus monticola obtained from embryonic tissue were exposed to 4 combinations of growth regulators (6-benzylaminopurine/NAA/IAA/IBA), either continuously for 6 weeks or by pulse treatment for 7 days, followed by 5 weeks culture without growth regulators. After 6 weeks of continuous exposure, rooting of shoots varied between 0 and 20%. Pulse treatment resulted in 40-64% rooting. In paired comparisons pulse treatments always provided better rooting percentages than did constant exposure treatments. Pulse treatments also produced longer (less than 2 mm) roots and more multiple roots.

Arthroscopic excision of ganglion cysts.

PubMed

Bontempo, Nicholas A; Weiss, Arnold-Peter C

2014-02-01

Arthroscopy is an advancing field in orthopedics, the applications of which have been expanding over time. Traditionally, excision of ganglion cysts has been done in an open fashion. However, more recently, studies show outcomes following arthroscopic excision to be as good as open excision. Cosmetically, the incisions are smaller and heal faster following arthroscopy. In addition, there is the suggested benefit that patients will regain function and return to work faster following arthroscopic excision. More prospective studies comparing open and arthroscopic excision of ganglion cysts need to be done in order to delineate if there is a true functional benefit. Copyright © 2014 Elsevier Inc. All rights reserved.

AAV-Mediated Gene Transfer to Dorsal Root Ganglion.

PubMed

Yu, Hongwei; Fischer, Gregory; Hogan, Quinn H

2016-01-01

Transferring genetic molecules into the peripheral sensory nervous system to manipulate nociceptive pathophysiology is a powerful approach for experimental modulation of sensory signaling and potentially for translation into therapy for chronic pain. This can be efficiently achieved by the use of recombinant adeno-associated virus (rAAV) in conjunction with nociceptor-specific regulatory transgene cassettes. Among different routes of delivery, direct injection into the dorsal root ganglia (DRGs) offers the most efficient AAV-mediated gene transfer selectively into the peripheral sensory nervous system. Here, we briefly discuss the advantages and applications of intraganglionic microinjection, and then provide a detailed approach for DRG injection, including a list of the necessary materials and description of a method for performing DRG microinjection experiments. We also discuss our experience with several adeno-associated virus (AAV) options for in vivo transgene expression in DRG neurons.

Intracellular chloride regulation in amphibian dorsal root ganglion neurones studied with ion-selective microelectrodes.

PubMed Central

Alvarez-Leefmans, F J; Gamiño, S M; Giraldez, F; Noguerón, I

1988-01-01

1. Intracellular Cl- activity (aiCl) and membrane potential (Em) were measured in frog dorsal root ganglion neurones (DRG neurones) using double-barrelled Cl- -selective microelectrodes. In standard Ringer solution buffered with HEPES (5 mM), equilibrated with air or 100% O2, the resting membrane potential was -57.7 +/- 1.0 mV and aiCl was 23.6 +/- 1.0 mM (n = 53). The value of aiCl was 2.6 times the activity expected for an equilibrium distribution and the difference between Em and ECl was 25 mV. 2. Removal of external Cl- led to a reversible fall in aiCl. Initial rates of decay and recovery of aiCl were 4.1 and 3.3 mM min-1, respectively. During the recovery of aiCl following return to standard Ringer solution, most of the movement of Cl- occurred against the driving force for a passive distribution. Changes in aiCl were not associated with changes in Em. Chloride fluxes estimated from initial rates of change in aiCl when external Cl- was removed were too high to be accounted for by electrodiffusion. 3. The intracellular accumulation of Cl- was dependent on the extracellular Cl- activity (aoCl). The relationship between aiCl and aoCl had a sigmoidal shape with a half-maximal activation of about 50 mM-external Cl-. 4. The steady-state aiCl depended on the simultaneous presence of extracellular Na+ and K+. Similarly, the active reaccumulation of Cl- after intracellular Cl- depletion was abolished in the absence of either Na+ or K+ in the bathing solution. 5. The reaccumulation of Cl- was inhibited by furosemide (0.5-1 x 10(-3) M) or bumetanide (10(-5) M). The decrease in aiCl observed in Cl- -free solutions was also inhibited by bumetanide. 6. Cell volume changes were calculated from the observed changes in aiCl. Cells were estimated to shrink in Cl- -free solutions to about 75% their initial volume, at an initial rate of 6% min-1. 7. The present results provide direct evidence for the active accumulation of Cl- in DRG neurones. The mechanism of Cl- transport is

Comparative expression analysis of POU4F1, POU4F2 and ISL1 in developing mouse cochleovestibular ganglion neurons

PubMed Central

Deng, Min; Yang, Hua; Xie, Xiaoling; Liang, Guoqing; Gan, Lin

2014-01-01

POU-homeodomain and LIM-homeodomain transcription factors are expressed in developing projection neurons within retina, inner ear, dorsal root ganglion, and trigeminal ganglion, and play synergistic roles in their differentiation and survival. Here, using immunohistochemistry, we present a comparative analysis of the spatiotemporal expression pattern of POU4F1, POU4F2, and ISL1 during the development of cochleovestibular ganglion (CVG) neurons in mouse inner ear. At early stages, when otic neurons are first detected in the otic epithelium (OE) and migrate into periotic mesenchyme to form the CVG, POU4F1 and ISL1 are co-expressed in a majority of the delaminated CVG neurons, which are marked by NEUROD1 expression, but POU4F1 is absent in the otic epithelium. The onset of POU4F2 expression starts after that of POU4F1 and ISL1, and is observed in the NEUROD1-negative, post-mitotic CVG neurons. When the CVG neurons innervate the vestibular and cochlear sensory organs, the expression of POU4F1, POU4F2, and ISL1 continues in both vestibular and spiral ganglion cells. Later in development, POU4F1 expression becomes down-regulated in a majority of spiral ganglion (SG) neurons and more neurons express POU4F2 expression while ISL1 expression is maintained. The differential as well as overlapping expression of POU4F1, POU4F2, and ISL1 combined with previous studies suggests possible functional interaction and regulatory relationship of these transcription factors in the development of inner ear neurons. PMID:24709358

The influence of IVF/ICSI treatment on human embryonic growth trajectories.

PubMed

Eindhoven, S C; van Uitert, E M; Laven, J S E; Willemsen, S P; Koning, A H J; Eilers, P H C; Exalto, N; Steegers, E A P; Steegers-Theunissen, R P M

2014-12-01

Is in vitro fertilization treatment with or without intracytoplasmatic sperm injection (IVF/ICSI) associated with changes in first and second trimester embryonic and fetal growth trajectories and birthweight in singleton pregnancies? Embryonic and fetal growth trajectories and birthweight are not significantly different between pregnancies conceived with IVF/ICSI treatment and spontaneously conceived pregnancies with reliable pregnancy dating. IVF/ICSI treatment has been associated with increased risks of preterm birth, fetal growth restriction and low birthweight. Decreased first-trimester crown-rump length (CRL) in the general population has been inversely associated with the same adverse pregnancy outcomes. In a prospective periconception birth cohort study conducted in a tertiary centre, 146 singleton pregnancies with reliable pregnancy dating and nonmalformed live borns were investigated, comprised of 88 spontaneous and 58 IVF/ICSI pregnancies. Serial 3D ultrasound scans were performed from 6 to 12 weeks of gestation. As estimates of embryonic growth, CRL and embryonic volume (EV) were measured using the I-Space virtual reality system. General characteristics were obtained from self-administered questionnaires at enrolment. Fetal growth parameters at 20 weeks and birthweight were obtained from medical records. To assess associations between IVF/ICSI and embryonic growth trajectories, estimated fetal weight and birthweight, stepwise linear mixed model analyses and linear regression analyses were performed using square root transformed CRL and fourth root transformed EV. In 146 pregnancies, 934 ultrasound scans were performed of which 849 (90.9%) CRLs and 549 (58.8%) EVs could be measured. Embryonic growth trajectories were comparable between IVF/ICSI pregnancies and spontaneously conceived pregnancies (CRL: βIVF/ICSI = 0.10√mm; P = 0.10; EV: βIVF/ICSI = 0.03(4)√cm³; P = 0.13). Estimated fetal weight and birthweight were also comparable between both

Transplantation of cells from eye-like structures differentiated from embryonic stem cells in vitro and in vivo regeneration of retinal ganglion-like cells.

PubMed

Aoki, Hitomi; Hara, Akira; Niwa, Masayuki; Motohashi, Tsutomu; Suzuki, Takashi; Kunisada, Takahiro

2008-02-01

An embryonic stem (ES) cell-derived eye-like structure, made up of neural retinal lineage cells, retinal pigment epithelial (RPE) cells, and lens cells was constructed in our laboratory. We have shown that cells from these eye-like structures can be integrated into the developing optic vesicle of chicks. The purpose of this study was to determine whether the cells from these eye-like structures can differentiate into retinal ganglion cells (RGCs) when transplanted into the vitreous of an injured adult mouse retina. ES cells were induced to differentiate into eye-like structures in vitro for 6 or 11 days. Recipient mouse eyes were injected with NMDA to injure the RGCs prior to the transplantation. Sham-treated eyes received the same amount of carrier vehicle. Cells were extracted from the eye-like structures and transplanted into the vitreous of damaged and control eyes. The host eyes were analyzed both qualitatively and quantitatively by immunohistochemistry 10 days or 8 weeks after transplantation. Cells from the ES cell-derived eye-like structures were integrated into the RGC layer, and differentiated into neurons when transplanted into control (non-NMDA-treated) adult eyes. However, they rarely expressed RGC markers. When they were transplanted into NMDA-treated eyes, the cells spread on the surface of the retina and covered a relatively large area of the host RGC layer that had been injured by the NMDA. The cells from the ES cell-derived eye cells frequently differentiated into cells expressing RGC-specific markers, and formed a new RGC layer. In addition, a small number of these ES cell-derived cells were observed to extend axon-like processes toward the optic disc of the host. However, visually evoked responses could not be recorded from the visual cortex. These findings suggest that ES cell-derived eye-like structures contain cells that can differentiate into RG-like cells and regenerate a new RGC layer. These cells also appeared to be integrated into the

Up-Regulation of the Biosynthesis and Release of Substance P through Wnt/β-Catenin Signaling Pathway in Rat Dorsal Root Ganglion Cells

PubMed Central

Li, Yu-Sang; Xi, Yang; Li, Xiao-Jun; Leng, Chang-Long; Jia, Mei-Mei; Zhang, Wei Kevin; Tang, He-Bin

2015-01-01

To examine regulatory effects of β-catenin on the biosynthesis and release of substance P, a rat chronic constriction injury (CCI) model and a rat dorsal root ganglion (DRG) cell culture model were used in the present study. The CCI treatment significantly induced the overall expression of β-catenin (158 ± 6% of sham) in the ipsilateral L5 DRGs in comparison with the sham group (109 ± 4% of sham). The CCI-induced aberrant expression of β-catenin was significantly attenuated by oral administration of diclofenac (119 ± 6% of the sham value; 10 mg/kg). Importantly, aberrant nuclear accumulation of β-catenin in cultured DRG cells resulted in up-regulation of the PPT-A mRNA expression and the substance P release. The up-regulation of both the PPT-A mRNA expression and the substance P release by either a GSK-3β inhibitor TWS119 (10 μM) or a Wnt signaling agonist Wnt-3a (100 ng/ml) were significantly abolished by an inhibitor of cyclooxygenase-2 (COX-2; NS-398, 1 μM). Collectively, these data suggest that nociceptive input-activated β-catenin signaling plays an important role in regulating the biosynthesis and release of substance P, which may contribute to the inflammation responses related to chronic pain. PMID:26054011

Oxaliplatin-Induced Peripheral Neuropathy via TRPA1 Stimulation in Mice Dorsal Root Ganglion Is Correlated with Aluminum Accumulation

PubMed Central

Roh, Kangsan; Kil, Eui-Joon; Lee, Minji; Auh, Chung-Kyun; Lee, Myung-Ah; Yeom, Chang-Hwan; Lee, Sukchan

2015-01-01

Oxaliplatin is a platinum-based anticancer drug used to treat metastatic colorectal, breast, and lung cancers. While oxaliplatin kills cancer cells effectively, it exhibits several side effects of varying severity. Neuropathic pain is commonly experienced during treatment with oxaliplatin. Patients describe symptoms of paresthesias or dysesthesias that are triggered by cold (acute neuropathy), or as abnormal sensory or motor function (chronic neuropathy). In particular, we found that aluminum levels were relatively high in some cancer patients suffering from neuropathic pain based on clinical observations. Based on these findings, we hypothesized that aluminum accumulation in the dorsal root ganglion (DRG) in the course of oxaliplatin treatment exacerbates neuropathic pain. In mice injected with oxaliplatin (three cycles of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest), we detected cold allodynia using the acetone test, but not heat hyperalgesia using a hot plate. However, co-treatment with aluminum chloride (AlCl3∙6H2O; 7 mg/kg i.p. for 14 days: equivalent 0.78 mg/kg of elemental Al) and oxaliplatin (1 cycle of 3 mg/kg i.p. daily for 5 days, followed by 5 days of rest) synergistically induced cold allodynia as well as increased TRPAl mRNA and protein expression. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis showed a significant increase in aluminum concentrations in the DRG of mice treated with aluminum chloride and oxaliplatin compared to aluminum chloride alone. Similarly, in a mouse induced-tumor model, aluminum concentrations were increased in DRG tissue and tumor cells after oxaliplatin treatment. Taken together, these findings suggest that aluminum accumulation in the DRG may exacerbate neuropathic pain in oxaliplatin-treated mice. PMID:25928068

Difference of acute dissociation and 1-day culture on the electrophysiological properties of rat dorsal root ganglion neurons.

PubMed

Song, Yuanlong; Zhang, Miaomiao; Tao, Xiaoqing; Xu, Zifen; Zheng, Yunjie; Zhu, Minjie; Zhang, Liangpin; Qiao, Jinhan; Gao, Linlin

2018-01-19

The dissociated dorsal root ganglion (DRG) neurons with or without culture were widely used for investigation of their electrophysiological properties. The culture procedures, however, may alter the properties of these neurons and the effects are not clear. In the present study, we recorded the action potentials (AP) and the voltage-gated Na + , K + , and Ca 2+ currents with patch clamp technique and measured the mRNA of Nav1.6-1.9 and Cav2.1-2.2 with real-time PCR technique from acutely dissociated and 1-day (1-d) cultured DRG neurons. The effects of the nerve growth factor (NGF) on the expression of Nav1.6-1.9 and Cav2.1-2.2 were evaluated. The neurons were classified as small (DRG-S), medium (DRG-M), and large (DRG-L), according to their size frequency distribution pattern. We found 1-d culture increased the AP size but reduced the excitability, and reduced the voltage-gated Na + and Ca 2+ currents and their corresponding mRNA expression in all types of neurons. The lack of NGF in the culture medium may contribute to the reduced Na + and Ca 2+ current, as the application of NGF recovered some of the reduced transcripts (Nav1.9, Cav2.1, and Cav2.2). 1-d culture showed neuron-type specific effects on some of the AP properties: it increased the maximum AP depolarizing rate (MDR) and hyperpolarized the resting membrane potential (RP) in DRG-M and DRG-L neurons, but slowed the maximum AP repolarizing rate (MRR) in DRG-S neurons. In conclusion, the 1-d cultured neurons had different properties with those of the acutely dissociated neurons, and lack of NGF may contribute to some of these differences.

Diversity in spatial scope of contrast adaptation among mouse retinal ganglion cells.

PubMed

Khani, Mohammad Hossein; Gollisch, Tim

2017-12-01

Retinal ganglion cells adapt to changes in visual contrast by adjusting their response kinetics and sensitivity. While much work has focused on the time scales of these adaptation processes, less is known about the spatial scale of contrast adaptation. For example, do small, localized contrast changes affect a cell's signal processing across its entire receptive field? Previous investigations have provided conflicting evidence, suggesting that contrast adaptation occurs either locally within subregions of a ganglion cell's receptive field or globally over the receptive field in its entirety. Here, we investigated the spatial extent of contrast adaptation in ganglion cells of the isolated mouse retina through multielectrode-array recordings. We applied visual stimuli so that ganglion cell receptive fields contained regions where the average contrast level changed periodically as well as regions with constant average contrast level. This allowed us to analyze temporal stimulus integration and sensitivity separately for stimulus regions with and without contrast changes. We found that the spatial scope of contrast adaptation depends strongly on cell identity, with some ganglion cells displaying clear local adaptation, whereas others, in particular large transient ganglion cells, adapted globally to contrast changes. Thus, the spatial scope of contrast adaptation in mouse retinal ganglion cells appears to be cell-type specific. This could reflect differences in mechanisms of contrast adaptation and may contribute to the functional diversity of different ganglion cell types. NEW & NOTEWORTHY Understanding whether adaptation of a neuron in a sensory system can occur locally inside the receptive field or whether it always globally affects the entire receptive field is important for understanding how the neuron processes complex sensory stimuli. For mouse retinal ganglion cells, we here show that both local and global contrast adaptation exist and that this diversity in

Diversity in spatial scope of contrast adaptation among mouse retinal ganglion cells

PubMed Central

Khani, Mohammad Hossein

2017-01-01

Retinal ganglion cells adapt to changes in visual contrast by adjusting their response kinetics and sensitivity. While much work has focused on the time scales of these adaptation processes, less is known about the spatial scale of contrast adaptation. For example, do small, localized contrast changes affect a cell’s signal processing across its entire receptive field? Previous investigations have provided conflicting evidence, suggesting that contrast adaptation occurs either locally within subregions of a ganglion cell’s receptive field or globally over the receptive field in its entirety. Here, we investigated the spatial extent of contrast adaptation in ganglion cells of the isolated mouse retina through multielectrode-array recordings. We applied visual stimuli so that ganglion cell receptive fields contained regions where the average contrast level changed periodically as well as regions with constant average contrast level. This allowed us to analyze temporal stimulus integration and sensitivity separately for stimulus regions with and without contrast changes. We found that the spatial scope of contrast adaptation depends strongly on cell identity, with some ganglion cells displaying clear local adaptation, whereas others, in particular large transient ganglion cells, adapted globally to contrast changes. Thus, the spatial scope of contrast adaptation in mouse retinal ganglion cells appears to be cell-type specific. This could reflect differences in mechanisms of contrast adaptation and may contribute to the functional diversity of different ganglion cell types. NEW & NOTEWORTHY Understanding whether adaptation of a neuron in a sensory system can occur locally inside the receptive field or whether it always globally affects the entire receptive field is important for understanding how the neuron processes complex sensory stimuli. For mouse retinal ganglion cells, we here show that both local and global contrast adaptation exist and that this diversity

Gene Therapy for Neuropathic Pain by Silencing of TNF-α Expression with Lentiviral Vectors Targeting the Dorsal Root Ganglion in Mice

PubMed Central

Ogawa, Nobuhiro; Kawai, Hiromichi; Terashima, Tomoya; Kojima, Hideto; Oka, Kazuhiro; Chan, Lawrence; Maegawa, Hiroshi

2014-01-01

Neuropathic pain can be a debilitating condition. Many types of drugs that have been used to treat neuropathic pain have only limited efficacy. Recent studies indicate that pro-inflammatory mediators including tumor necrosis factor α (TNF-α) are involved in the pathogenesis of neuropathic pain. In the present study, we engineered a gene therapy strategy to relieve neuropathic pain by silencing TNF-α expression in the dorsal root ganglion (DRG) using lentiviral vectors expressing TNF short hairpin RNA1-4 (LV-TNF-shRNA1-4) in mice. First, based on its efficacy in silencing TNF-α in vitro, we selected shRNA3 to construct LV-TNF-shRNA3 for in vivo study. We used L5 spinal nerve transection (SNT) mice as a neuropathic pain model. These animals were found to display up-regulated mRNA expression of activating transcription factor 3 (ATF3) and neuropeptide Y (NPY), injury markers, and interleukin (IL)-6, an inflammatory cytokine in the ipsilateral L5 DRG. Injection of LV-TNF-shRNA3 onto the proximal transected site suppressed significantly the mRNA levels of ATF3, NPY and IL-6, reduced mechanical allodynia and neuronal cell death of DRG neurons. These results suggest that lentiviral-mediated silencing of TNF-α in DRG relieves neuropathic pain and reduces neuronal cell death, and may constitute a novel therapeutic option for neuropathic pain. PMID:24642694

Agmatine protects retinal ganglion cells from hypoxia-induced apoptosis in transformed rat retinal ganglion cell line

PubMed Central

Hong, Samin; Lee, Jong Eun; Kim, Chan Yun; Seong, Gong Je

2007-01-01

Background Agmatine is an endogenous polyamine formed by the decarboxylation of L-arginine. We investigated the protective effects of agmatine against hypoxia-induced apoptosis of immortalized rat retinal ganglion cells (RGC-5). RGC-5 cells were cultured in a closed hypoxic chamber (5% O2) with or without agmatine. Cell viability was determined by lactate dehydrogenase (LDH) assay and apoptosis was examined by annexin V and caspase-3 assays. Expression and phosphorylation of mitogen-activated protein kinases (MAPKs; JNK, ERK p44/42, and p38) and nuclear factor-kappa B (NF-κB) were investigated by Western immunoblot analysis. The effects of agmatine were compared to those of brain-derived neurotrophic factor (BDNF), a well-known protective neurotrophin for retinal ganglion cells. Results After 48 hours of hypoxic culture, the LDH assay showed 52.3% cell loss, which was reduced to 25.6% and 30.1% when agmatine and BDNF were administered, respectively. This observed cell loss was due to apoptotic cell death, as established by annexin V and caspase-3 assays. Although total expression of MAPKs and NF-κB was not influenced by hypoxic injury, phosphorylation of these two proteins was increased. Agmatine reduced phosphorylation of JNK and NF-κB, while BDNF suppressed phosphorylation of ERK and p38. Conclusion Our results show that agmatine has neuroprotective effects against hypoxia-induced retinal ganglion cell damage in RGC-5 cells and that its effects may act through the JNK and NF-κB signaling pathways. Our data suggest that agmatine may lead to a novel therapeutic strategy to reduce retinal ganglion cell injury related to hypoxia. PMID:17908330

Effect of nerve injury on the number of dorsal root ganglion neurons and autotomy behavior in adult Bax-deficient mice.

PubMed

Lyu, Chuang; Lyu, Gong-Wei; Martinez, Aurora; Shi, Tie-Jun Sten

2017-01-01

The proapoptotic molecule BAX, plays an important role in mitochondrial apoptotic pathway. Dorsal root ganglion (DRG) neurons depend on neurotrophic factors for survival at early developmental stages. Withdrawal of neurotrophic factors will induce apoptosis in DRG neurons, but this type of cell death can be delayed or prevented in neonatal Bax knockout (KO) mice. In adult animals, evidence also shows that DRG neurons are less dependent upon neurotrophic factors for survival. However, little is known about the effect of Bax deletion on the survival of normal and denervated DRG neurons in adult mice. A unilateral sciatic nerve transection was performed in adult Bax KO mice and wild-type (WT) littermates. Stereological method was employed to quantify the number of lumbar-5 DRG neurons 1 month post-surgery. Nerve injury-induced autotomy behavior was also examined on days 1, 3, and 7 post-surgery. There were significantly more neurons in contralateral DRGs of KO mice as compared with WT mice. The number of neurons was reduced in ipsilateral DRGs in both KO and WT mice. No changes in size distributions of DRG neuron profiles were detected before or after nerve injury. Injury-induced autotomy behavior developed much earlier and was more serious in KO mice. Although postnatal death or loss of DRG neurons is partially prevented by Bax deletion, this effect cannot interfere with long-term nerve injury-induced neuronal loss. The exaggerated self-amputation behavior observed in the mutant mice indicates that Bax deficiency may enhance the development of spontaneous pain following nerve injury.

Spiral Ganglion Stem Cells Can Be Propagated and Differentiated Into Neurons and Glia

PubMed Central

Zecha, Veronika; Wagenblast, Jens; Arnhold, Stefan; Edge, Albert S. B.; Stöver, Timo

2014-01-01

Abstract The spiral ganglion is an essential functional component of the peripheral auditory system. Most types of hearing loss are associated with spiral ganglion cell degeneration which is irreversible due to the inner ear's lack of regenerative capacity. Recent studies revealed the existence of stem cells in the postnatal spiral ganglion, which gives rise to the hope that these cells might be useful for regenerative inner ear therapies. Here, we provide an in-depth analysis of sphere-forming stem cells isolated from the spiral ganglion of postnatal mice. We show that spiral ganglion spheres have characteristics similar to neurospheres isolated from the brain. Importantly, spiral ganglion sphere cells maintain their major stem cell characteristics after repeated propagation, which enables the culture of spheres for an extended period of time. In this work, we also demonstrate that differentiated sphere-derived cell populations not only adopt the immunophenotype of mature spiral ganglion cells but also develop distinct ultrastructural features of neurons and glial cells. Thus, our work provides further evidence that self-renewing spiral ganglion stem cells might serve as a promising source for the regeneration of lost auditory neurons. PMID:24940560

Egr1 gene knockdown affects embryonic ocular development in zebrafish.

PubMed

Hu, Chao-Yu; Yang, Chang-Hao; Chen, Wei-Yu; Huang, Chiu-Ju; Huang, Hsing-Yen; Chen, Muh-Shy; Tsai, Huai-Jen

2006-10-26

To identify the changes in zebrafish embryonic ocular development after early growth response factor 1 (Egr1) gene knockdown by Egr1-specific translation inhibitor, morpholino oligonucleotides (MO). Two kinds of Egr1-MO were microinjected separately with various dosages into one to four celled zebrafish embryos to find an optimal dose generating an acceptable mortality rate and high frequency of specific phenotype. Chordin-MO served as the positive control; a 5 mismatch MO of Egr1-MO1 and a nonspecific MO served as negative controls. We graded the Egr1 morphants according to their gross abnormalities, and measured their ocular dimensions accordingly. Western blot analysis and synthetic Egr1 mRNA rescue experiments confirmed whether the deformities were caused by Egr1 gene knockdown. Histological examination and three kinds of immunohistochemical staining were applied to identify glutamate receptor one expression in retinal ganglion cells and amacrine cells, to recognize acetylated alpha-tubulin expression which indicated axonogenesis, and to label photoreceptor cells with zpr-1 antibody. After microinjection of 8 ng Egr1-MO1 or 2 ng Egr1-MO2, 81.8% and 97.3% of larvae at 72 h postfertilization had specific defects, respectively. The gross phenotype included string-like heart, flat head, and deformed tail. The more severely deformed larvae had smaller eyes and pupils. Co-injection of 8 ng Egr1-MO1 and supplementary 12 pg synthetic Egr1 mRNA reduced the gross abnormality rate from 84.4% to 29.7%, and decreased the severity of deformities. Egr1 protein appeared in the wildtype and rescued morphants, but was lacking in the Egr1 morphants with specific deformities. Lenses of Egr1 morphants were smaller and had some residual nucleated lens fiber cells. Morphants' retinal cells arranged disorderly and compactly with thin plexiform layers. Immunohistochemical studies showed that morphants had a markedly decreased number of mature retinal ganglion cells, amacrine cells, and

The Ciliary Margin Zone of the Mammalian Retina Generates Retinal Ganglion Cells.

PubMed

Marcucci, Florencia; Murcia-Belmonte, Veronica; Wang, Qing; Coca, Yaiza; Ferreiro-Galve, Susana; Kuwajima, Takaaki; Khalid, Sania; Ross, M Elizabeth; Mason, Carol; Herrera, Eloisa

2016-12-20

The retina of lower vertebrates grows continuously by integrating new neurons generated from progenitors in the ciliary margin zone (CMZ). Whether the mammalian CMZ provides the neural retina with retinal cells is controversial. Live imaging of embryonic retina expressing eGFP in the CMZ shows that cells migrate laterally from the CMZ to the neural retina where differentiated retinal ganglion cells (RGCs) reside. Because Cyclin D2, a cell-cycle regulator, is enriched in ventral CMZ, we analyzed Cyclin D2 -/- mice to test whether the CMZ is a source of retinal cells. Neurogenesis is diminished in Cyclin D2 mutants, leading to a reduction of RGCs in the ventral retina. In line with these findings, in the albino retina, the decreased production of ipsilateral RGCs is correlated with fewer Cyclin D2 + cells. Together, these results implicate the mammalian CMZ as a neurogenic site that produces RGCs and whose proper generation depends on Cyclin D2 activity. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Characterization of Ganglionic Acetylcholine Receptor Autoantibodies

PubMed Central

Vernino, Steven; Lindstrom, Jon; Hopkins, Steve; Wang, Zhengbei; Low, Phillip A.

2008-01-01

In myasthenia gravis (MG), autoantibodies bind to the α1 subunit and other subunits of the muscle nicotinic acetylcholine receptor (AChR). Autoimmune autonomic ganglionopathy (AAG) is an antibody-mediated neurological disorder caused by antibodies against neuronal AChRs in autonomic ganglia. Subunits of muscle and neuronal AChR are homologous. We examined the specificity of AChR antibodies in patients with MG and AAG. Ganglionic AChR autoantibodies found in AAG patients are specific for AChRs containing the α3 subunit. Muscle and ganglionic AChR antibody specificities are distinct. Antibody crossreactivity between AChRs with different α subunits is uncommon but can occur. PMID:18485491

Ganglionic adrenergic action modulates ovarian steroids and nitric oxide in prepubertal rat.

PubMed

Delgado, Silvia Marcela; Casais, Marilina; Sosa, Zulema; Rastrilla, Ana María

2006-08-01

Both peripheral innervation and nitric oxide (NO) participate in ovarian steroidogenesis. The purpose of this work was to analyse the ganglionic adrenergic influence on the ovarian release of steroids and NO and the possible steroids/NO relationship. The experiments were carried out in the ex vivo coeliac ganglion-superior ovarian nerve (SON)-ovary system of prepubertal rats. The coeliac ganglion-SON-ovary system was incubated in Krebs Ringer-bicarbonate buffer in presence of adrenergic agents in the ganglionic compartment. The accumulation of progesterone, androstenedione, oestradiol and NO in the ovarian incubation liquid was measured. Norepinephrine in coeliac ganglion inhibited the liberation of progesterone and increased androstenedione, oestradiol and NO in ovary. The addition of alpha and beta adrenergic antagonists also showed different responses in the liberation of the substances mentioned before, which, from a physiological point of view, reveals the presence of adrenergic receptors in coeliac ganglion. In relation to propranolol, it does not revert the effect of noradrenaline on the liberation of progesterone, which leads us to think that it might also have a "per se" effect on the ganglion, responsible for the ovarian response observed for progesterone. Finally, we can conclude that the ganglionic adrenergic action via SON participates on the regulation of the prepubertal ovary in one of two ways: either increasing the NO, a gaseous neurotransmitter with cytostatic characteristics, to favour the immature follicles to remain dormant or increasing the liberation of androstenedione and oestradiol, the steroids necessary for the beginning of the near first estral cycle.

Evidence that ganglion cells react to retinal detachment.

PubMed

Coblentz, Francie E; Radeke, Monte J; Lewis, Geoffrey P; Fisher, Steven K

2003-03-01

Growth associated protein 43 (GAP 43) is involved in synapse formation and it is expressed in the retina in a very specific pattern. Although GAP 43 is downregulated at the time of synapse formation, it can be re-expressed following injury such as axotomy or ischemia. Because of this we sought to characterize the expression of GAP 43 after retinal detachment (RD). Immunoblot, immunocytochemical and quantitative polymerase chain reaction (QPCR) techniques were used to assess the level of GAP 43 expression after experimental RD. GAP 43 was localized to three sublaminae of the inner plexiform layer of the normal retina. GAP 43 became upregulated in a subset of retinal ganglion cells following at least 7 days of RD. By immunoblot GAP 43 could be detected by 3 days. QPCR shows the upregulation of GAP 43 message by 6hr of detachment. To further characterize changes in ganglion cells, we used an antibody to neurofilament 70 and 200kDa (NF) proteins. Anti-NF labels horizontal cells, ganglion cell dendrites in the inner plexiform layer, and ganglion cell axons (fasicles) in the normal retina. Following detachment it is upregulated in horizontal cells and ganglion cells. When detached retina was double labelled with anti-GAP 43 and anti-NF, some cells were labelled with both markers, while others labelled with only one. We have previously shown that second order neurons respond to detachment; here we show that third order neurons are responding as well. Cellular remodelling of this type in response to detachment may explain the slow recovery of vision that often occurs after reattachment, or those changes that are often assumed to be permanent.

Retinal ganglion cell topography and spatial resolving power in penguins.

PubMed

Coimbra, João Paulo; Nolan, Paul M; Collin, Shaun P; Hart, Nathan S

2012-01-01

Penguins are a group of flightless seabirds that exhibit numerous morphological, behavioral and ecological adaptations to their amphibious lifestyle, but little is known about the topographic organization of neurons in their retinas. In this study, we used retinal wholemounts and stereological methods to estimate the total number and topographic distribution of retinal ganglion cells in addition to an anatomical estimate of spatial resolving power in two species of penguins: the little penguin, Eudyptula minor, and the king penguin, Aptenodytes patagonicus. The total number of ganglion cells per retina was approximately 1,200,000 in the little penguin and 1,110,000 in the king penguin. The topographic distribution of retinal ganglion cells in both species revealed the presence of a prominent horizontal visual streak with steeper gradients in the little penguin. The little penguin retinas showed ganglion cell density peaks of 21,867 cells/mm², affording spatial resolution in water of 17.07-17.46 cycles/degree (12.81-13.09 cycles/degree in air). In contrast, the king penguin showed a relatively lower peak density of ganglion cells of 14,222 cells/mm², but--due to its larger eye--slightly higher spatial resolution in water of 20.40 cycles/degree (15.30 cycles/degree in air). In addition, we mapped the distribution of giant ganglion cells in both penguin species using Nissl-stained wholemounts. In both species, topographic mapping of this cell type revealed the presence of an area gigantocellularis with a concentric organization of isodensity contours showing a peak in the far temporal retina of approximately 70 cells/mm² in the little penguin and 39 cells/mm² in the king penguin. Giant ganglion cell densities gradually fall towards the outermost isodensity contours revealing the presence of a vertically organized streak. In the little penguin, we confirmed our cytological characterization of giant ganglion cells using immunohistochemistry for microtubule

High-frequency transcutaneous electrical nerve stimulation attenuates postsurgical pain and inhibits excess substance P in rat dorsal root ganglion.

PubMed

Chen, Yu-Wen; Tzeng, Jann-Inn; Lin, Min-Fei; Hung, Ching-Hsia; Hsieh, Pei-Ling; Wang, Jhi-Joung

2014-01-01

Transcutaneous electrical nerve stimulation (TENS) is a common therapeutic modality for pain management, but its effectiveness in skin/muscle incision and retraction (SMIR)-evoked pain is unknown. We aimed to examine the effects of TENS on postoperative pain and the levels of substance P (SP), N-methyl-D-aspartate receptor 1 (NR1), and interleukin 1β (IL-1β) in rat dorsal root ganglion (DRG). High-frequency (100 Hz) TENS was administered daily beginning on postoperative day 1 (POD1) and continued until animal subjects were killed for tissues. Mechanical sensitivity to von Frey stimuli (6g and 15g) and the levels of NR1, SP, and IL-1β in DRG were assessed in the sham-operated, SMIR-operated, TENS after SMIR surgery, and placebo-TENS after SMIR surgery groups. Skin/muscle incision and retraction rats exhibited a significant hypersensitivity to von Frey stimuli on POD3. In contrast with SMIR rats, SMIR-operated rats receiving TENS therapy demonstrated a rapid recovery of mechanical hypersensitivity. The SMIR-operated rats showed an up-regulation of NR1, SP, and IL-1β in DRG on PODs 14 and 28, whereas the SMIR-operated rats after TENS administration reversed this up-regulation. By contrast, the placebo-TENS after SMIR operation did not alter postsurgical pain nor the levels of NR1, SP, and IL-1β. Our data demonstrated that TENS intervention reduced persistent postoperative pain caused by SMIR operation. Up-regulation of NR1, SP, and IL-1β in DRG, activated after SMIR surgery, is important in the development of prolonged postincisional pain. The TENS pain relief may be related to the suppression of NR1, SP, and IL-1β in DRG of SMIR rats.

Sphenopalatine ganglion: block, radiofrequency ablation and neurostimulation - a systematic review.

PubMed

Ho, Kwo Wei David; Przkora, Rene; Kumar, Sanjeev

2017-12-28

Sphenopalatine ganglion is the largest collection of neurons in the calvarium outside of the brain. Over the past century, it has been a target for interventional treatment of head and facial pain due to its ease of access. Block, radiofrequency ablation, and neurostimulation have all been applied to treat a myriad of painful syndromes. Despite the routine use of these interventions, the literature supporting their use has not been systematically summarized. This systematic review aims to collect and summarize the level of evidence supporting the use of sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Medline, Google Scholar, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were reviewed for studies on sphenopalatine ganglion block, radiofrequency ablation and neurostimulation. Studies included in this review were compiled and analyzed for their treated medical conditions, study design, outcomes and procedural details. Studies were graded using Oxford Center for Evidence-Based Medicine for level of evidence. Based on the level of evidence, grades of recommendations are provided for each intervention and its associated medical conditions. Eighty-three publications were included in this review, of which 60 were studies on sphenopalatine ganglion block, 15 were on radiofrequency ablation, and 8 were on neurostimulation. Of all the studies, 23 have evidence level above case series. Of the 23 studies, 19 were on sphenopalatine ganglion block, 1 study on radiofrequency ablation, and 3 studies on neurostimulation. The rest of the available literature was case reports and case series. The strongest evidence lies in using sphenopalatine ganglion block, radiofrequency ablation and neurostimulation for cluster headache. Sphenopalatine ganglion block also has evidence in treating trigeminal neuralgia, migraines, reducing the needs of analgesics after endoscopic sinus surgery and reducing pain associated with nasal packing

Structural basis of orientation sensitivity of cat retinal ganglion cells.

PubMed

Leventhal, A G; Schall, J D

1983-11-10

We investigated the structural basis of the physiological orientation sensitivity of retinal ganglion cells (Levick and Thibos, '82). The dendritic fields of 840 retinal ganglion cells labeled by injections of horseradish peroxidase into the dorsal lateral geniculate nucleus (LGNd) or optic tracts of normal cats. Siamese cats, and cat deprived of patterned visual experience from birth by monocular lid-suture (MD) were studied. Mathematical techniques designed to analyze direction were used to find the dendritic field orientation of each cell. Statistical techniques designed for angular data were used to determine the relationship between dendritic field orientation and angular position on the retina (polar angle). Our results indicate that 88% of retinal ganglion cells have oriented dendritic fields and that dendritic field orientation is related systematically to retinal position. In all regions of retina more that 0.5 mm from the area centralis the dendritic fields of retinal ganglion cells are oriented radially, i.e., like the spokes of a wheel having the area centralis at its hub. This relationship was present in all animals and cell types studied and was strongest for cells located close to the horizontal meridian (visual streak) of the retina. Retinal ganglion cells appear to be sensitive to stimulus orientation because they have oriented dendritic fields.

Morphology of retinal ganglion cells in the ferret (Mustela putorius furo).

PubMed

Isayama, Tomoki; O'Brien, Brendan J; Ugalde, Irma; Muller, Jay F; Frenz, Aaron; Aurora, Vikas; Tsiaras, William; Berson, David M

2009-12-01

The ferret is the premiere mammalian model of retinal and visual system development, but the spectrum and properties of its retinal ganglion cells are less well understood than in another member of the Carnivora, the domestic cat. Here, we have extensively surveyed the dendritic architecture of ferret ganglion cells and report that the classification scheme previously developed for cat ganglion cells can be applied with few modifications to the ferret retina. We confirm the presence of alpha and beta cells in ferret retina, which are very similar to those in cat retina. Both cell types exhibited an increase in dendritic field size with distance from the area centralis (eccentricity) and with distance from the visual streak. Both alpha and beta cell populations existed as two subtypes whose dendrites stratified mainly in sublamina a or b of the inner plexiform layer. Six additional morphological types of ganglion cells were identified: four monostratified cell types (delta, epsilon, zeta, and eta) and two bistratified types (theta and iota). These types closely resembled their counterparts in the cat in terms of form, relative field size, and stratification. Our data indicate that, among carnivore species, the retinal ganglion cells resemble one another closely and that the ferret is a useful model for studies of the ontogenetic differentiation of ganglion cell types.

Ganglion cyst of the temporomandibular joint.

PubMed

Heng-Kun, W; Yan-Ling, G; Wen-Feng, Z; Zhe, S; Ren-Xin, W; Xiao-Tao, Z

2014-02-01

Ganglion cyst of the temporomandibular joint is a rare disease, which may arise from myxoid degeneration of the collagenous tissue of the temporomandibular joint capsule, without epithelial or endothelial lining. We report a case of cystic lesion in a 40-year-old female patient. The patient had a left pre-auricular oval-shaped swelling without any articular symptoms. The pathological analysis after surgical removal allowed diagnosing the lesion as a ganglion cyst of the left temporomandibular joint. We made a literature review and noted that this condition was predominant in female patients. We recommend using MRI for diagnostic purposes and surgery as the best therapeutic alternative. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Effect of lappaconitine on neuropathic pain mediated by P2X3 receptor in rat dorsal root ganglion.

PubMed

Ou, Shan; Zhao, Yan-Dong; Xiao, Zhi; Wen, Hui-Zhong; Cui, Jian; Ruan, Huai-Zhen

2011-04-01

ATP facilitates initiation and transmission of the neuropathic pain at the dorsal root ganglion (DRG) level via the P2X receptors, especially the subtype P2X(3). Lappaconitine (LA) is an active principle isolated from Chinese herbal medicine and possesses analgesic effect. The aim of this study was to investigate the effect of LA on chronic constriction injury (CCI)-induced neuropathic pain mediated by P2X(3) receptor in the DRG neurons. In the presence of CCI and/or LA, the mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured and P2X(3) receptor expression in the DRG neurons was evaluated by immunohistochemistry and Western blotting. Following intrathecal administration of P2X(3) receptor oligonucleotide, the effect of LA on pain thresholds was assessed. Furthermore, the effect of LA on the P2X(3) receptor agonists ATP- and α,β-meATP-induced inward currents (I(ATP) and I(α,β-meATP)) in the acutely dissociated rat DRG neurons was investigated by whole cell patch-clamp. The results included: (1) There showed reduction of pain thresholds, enhancement of I(ATP) and I(α,β-meATP) and up-regulation of P2X(3) receptor expression in rat DRG neurons when neuropathic pain occurred. (2) In the presence of LA, the decreased pain thresholds, the up-regulated P2X(3) receptor expression and the enhanced I(ATP) and I(α,β-meATP) were reversible in the CCI rats. (3) The down-regulated P2X(3) receptor expression with pretreatment of P2X(3) receptor antisense oligonucleotide significantly attenuated the analgesic effect of LA. These results indicate that the analgesic effect of LA involves decrease of expression and sensitization of the P2X(3) receptors of the rat DRG neurons following CCI. Copyright © 2011 Elsevier Ltd. All rights reserved.

Changes in morphology of retinal ganglion cells with eccentricity in retinal degeneration.

PubMed

Anderson, E E; Greferath, U; Fletcher, E L

2016-05-01

Ganglion cells are the output neurons of the retina and are known to remodel during the subtle plasticity changes that occur following the death of photoreceptors in inherited retinal degeneration. We examine the influence of retinal eccentricity on anatomical remodelling and ganglion cell morphology well after photoreceptor loss. Rd1 mice that have a mutation in the β subunit of phosphodiesterase 6 were used as a model of retinal degeneration and gross remodelling events were examined by processing serial sections for immunocytochemistry. Retinal wholemounts from rd1-Thy1 and control Thy1 mice that contained a fluorescent protein labelling a subset of ganglion cells were processed for immunohistochemistry at 11 months of age. Ganglion cells were classified based on their soma size, dendritic field size and dendritic branching pattern and their dendritic fields were analysed for their length, area and quantity of branching points. Overall, more remodelling was found in the central compared with the peripheral retina. In addition, the size and complexity of A2, B1, C1 and D type ganglion cells located in the central region of the retina decreased. We propose that the changes in ganglion cell morphology are correlated with remodelling events in these regions and impact the function of retinal circuitry in the degenerated retina.

A Case Report of an Acromioclavicular Joint Ganglion Associated with a Rotator Cuff Tear.

PubMed

Tanaka, Suguru; Gotoh, Masafumi; Mitsui, Yasuhiro; Shirachi, Isao; Okawa, Takahiro; Higuchi, Fujio; Shiba, Naoto

2017-04-13

We report a case of subcutaneous ganglion adjacent to the acromioclavicular joint with massive rotator cuff tear [1-7]. An 81-year-old woman presented with a ganglion adjacent to the acromioclavicular joint that had first been identified 9 months earlier. The ganglion had recurred after having been aspirated by her local physician, so she was referred to our hospital. The puncture fluid was yellowish, clear and viscous. Magnetic resonance imaging identified a massive rotator cuff tear with multi- lobular cystic lesions continuous to the acromioclavicular joint, presenting the "geyser sign". During arthroscopy, distal clavicular resection and excision of the ganglion were performed together with joint debridement. At present, the ganglion has not recurred and the patient has returned to normal daily activity. In this case, the ganglion may have developed subsequent to the concomitant massive cuff tear, due to subcutaneous fluid flow through the damaged acromioclavicular joint.

Synaptic potentials recorded by the sucrosegap method from the rabbit superior cervical ganglion

PubMed Central

Kosterlitz, H. W.; Lees, G. M.; Wallis, D. I.

1970-01-01

1. Compound ganglionic potentials evoked by stimulation of the preganglionic nerves to the superior cervical ganglion of the rabbit were recorded by the sucrose-gap method. 2. When the distal part of the ganglion was bathed in flowing isotonic sucrose solution or sodium-deficient solutions, ganglionic action potentials were no longer evoked, only large synaptic potentials. 3. The compound synaptic potential, which remained unaltered for more than 1 h, originated in a population of cells at the interface between the Krebs and sucrose solutions. Hexamethonium reduced the size but did not alter the time course of the synaptic potential. 4. It is suggested that a higher concentration of sodium ions is required for the generation of ganglionic action potentials than for either conduction in the postganglionic axons or production of synaptic potentials. 5. When lithium replaced sodium in the solution bathing the distal part of the ganglion, the synaptic potential was greatly reduced in amplitude. Impulse propagation in the postganglionic axons was only slightly impaired when lithium replaced sodium in the solution bathing the axons. 6. A quantitative assessment of the potency of the ganglion-blocking drugs nicotine, pentolinium, hexamethonium and pempidine was made by measuring the depression of the synaptic potentials produced by bathing the distal part of the ganglion in flowing isotonic sucrose solution. The concentrations which produced a 50% depression were 8·1 μM nicotine, 26·5 μM pentolinium, 111 μM hexamethonium and 22·2 μM pempidine. PMID:5492898

Transcription Factors SOX4 and SOX11 Function Redundantly to Regulate the Development of Mouse Retinal Ganglion Cells*

PubMed Central

Jiang, Ying; Ding, Qian; Xie, Xiaoling; Libby, Richard T.; Lefebvre, Veronique; Gan, Lin

2013-01-01

SOX family proteins belong to the high-mobility-group (HMG) domain-containing transcription factors, and function as key players to regulate embryonic development and cell fate determination. The highly related group C Sox genes Sox4 and Sox11 are widely expressed in the development of mouse retina and share a similar expression pattern with each other in this process. Here, to investigate the roles of Sox4 and Sox11 in the retinal development, Sox4, Sox11, and Sox4/Sox11 conditional knock-out (CKO) mice with deletion of Sox4, Sox11, and Sox4/Sox11 in retinas were generated. Our studies demonstrated that targeted disruption of Sox4 or Sox11 in retinas caused a moderate reduction of generation of RGCs. However, a complete loss of RGCs was observed in Sox4/Sox11-null retinas, suggesting the two genes play similar roles in the development of RGCs. Our further analysis confirms that Sox4 and Sox11 function redundantly to regulate the generation of RGCs at early embryonic stages as well as the survival of RGCs at late embryonic stages. In addition, we demonstrated that loss of Math5 impairs the expression of Sox4 and Sox11 in the ganglion cell layer while deletion of Brn3b has no effect on the expression of Sox4 and Sox11. Taken together, these findings elucidate SoxC genes as essential contributors to maintain the survival of RGCs, and imply their intermediate position between Math5 and Brn3b in the genetic hierarchy of RGC development. PMID:23649630

Regenerating reptile retinas: a comparative approach to restoring retinal ganglion cell function.

PubMed

Williams, D L

2017-02-01

Transection or damage to the mammalian optic nerve generally results in loss of retinal ganglion cells by apoptosis. This cell death is seen less in fish or amphibians where retinal ganglion cell survival and axon regeneration leads to recovery of sight. Reptiles lie somewhere in the middle of this spectrum of nerve regeneration, and different species have been reported to have a significant variation in their retinal ganglion cell regenerative capacity. The ornate dragon lizard Ctenophoris ornatus exhibits a profound capacity for regeneration, whereas the Tenerife wall lizard Gallotia galloti has a more variable response to optic nerve damage. Some individuals regain visual activity such as the pupillomotor responses, whereas in others axons fail to regenerate sufficiently. Even in Ctenophoris, although the retinal ganglion cell axons regenerate adequately enough to synapse in the tectum, they do not make long-term topographic connections allowing recovery of complex visually motivated behaviour. The question then centres on where these intraspecies differences originate. Is it variation in the innate ability of retinal ganglion cells from different species to regenerate with functional validity? Or is it variances between different species in the substrate within which the nerves regenerate, the extracellular environment of the damaged nerve or the supporting cells surrounding the regenerating axons? Investigations of retinal ganglion cell regeneration between different species of lower vertebrates in vivo may shed light on these questions. Or perhaps more interesting are in vitro studies comparing axon regeneration of retinal ganglion cells from various species placed on differing substrates.

[The influence of partial dorsal root rhizotomy on IGF-I expression in spared root ganglion and spinal cord].

PubMed

Wang, Wei-min; Guan, Yu-guang; Liu, Fen; Wang, Ting-hua; Xu, Xin-yun; Ke, Qing; Lu, Yong-chao; Yuan, Yuan

2005-01-01

To explore the temporospatial changes of IGF-I expression in the spared dorsal root ganglia (DRG, L6) on the operated side and un-operated side, in the spinal lamina II (L3, L5, L6) and Clarke's nucleus (L3) of the adult cats that have undergone partial dorsal rhizotomy, and compare them against those of the normal adult cats so as to unveil the relation between IGF-I and the plasticity of spinal cord. Fifteen male adult cats were divided into three groups. The cats of two groups were subjected to unilateral partial dorsal root rhizotomy (L1-L5, L7-S2 DRG were sectioned, but L6 was spared) and were sacrificed at 7 days and 14 days after operation. The bilateral L6 dorsal root ganglia and L3, L5, L6 spinal cord of all groups were made into frozen sections 20 microm thick. Then, the sections were stained by the immunohistochemistry ABC method using IGF-I (1:200, Santa Cruz) antibody. The distribution and the number of IGF-I positive neurons in bilateral spared DRG (L6) on the operated/un-operated side, in spinal lamina I (L3, L5, L6) and in Clarke' nucleus (L3) of each animal were observed and counted. All data were analyzed by one-way ANOVA, SNK-q test and paired-t test. (1) Seven days after partial dorsal root rhizotomy, the number of IGF-I positive neurons in spared DRG on the operated side declined as compared with that of normal group (P<0.05), but it was not significantly different from that of L6 spared DRG on the un-operated side (P>0.05). On the 14th day, the IGF-I expression in neurons of L6 DRG on the operated side was significantly lower than that of normal group and that of L6 spared DRG on the unoperated side (P<0.01), but it was not significantly different from that of the 7th day group (P>0.05). (2) There was no difference in number of IGF-I positive neuron in L3, L5, L6 spinal lamina II between normal group, 7th day post-operation group and 14th day post-operation group (P>0.05). After operation, IGF-I expression in Clarke's nucleus declined on the 7

The role of TRPV1 in different subtypes of dorsal root ganglion neurons in rat chronic inflammatory nociception induced by complete Freund's adjuvant

PubMed Central

Yu, Lu; Yang, Fei; Luo, Hao; Liu, Feng-Yu; Han, Ji-Sheng; Xing, Guo-Gang; Wan, You

2008-01-01

Background The present study aims to investigate the role of transient receptor potential vanilloid 1 (TRPV1) in dorsal root ganglion (DRG) neurons in chronic pain including thermal hyperalgesia and mechanical allodynia. Chronic inflammatory nociception of rats was produced by intraplantar injection of complete Freund's adjuvant (CFA) and data was collected until day 28 following injection. Results Thermal hyperalgesia was evident from day 1 to day 28 with peak at day 7, while mechanical allodynia persisted from day 1 to day 14 and was greatest at day 7. Intrathecal administration of AMG 9810 at day 7, a selective TRPV1 antagonist, significantly reduced thermal hyperalgesia and mechanical allodynia. TRPV1 expression in DRG detected by Western blotting was increased relative to baseline throughout the observation period. Double labeling of TRPV1 with neuronal marker neurofilament 200 (NF200), calcitonin gene-related peptide (CGRP) or isolectin B4 (IB4) was used to distinguish different subtypes of DRG neurons. TRPV1 expression was increased in the medium-sized myelinated A fiber (NF200 positive) neurons and in small non-peptidergic (IB4 positive) neurons from day 1 to day 14 and was increased in small peptidergic (CGRP positive) neurons from day 1 to day 28. Conclusion TRPV1 expression increases in all three types of DRG neurons after CFA injection and plays a role in CFA-induced chronic inflammatory pain including thermal hyperalgesia and mechanical allodynia. PMID:19055783

Enhanced excitability of small dorsal root ganglion neurons in rats with bone cancer pain

PubMed Central

2012-01-01

Background Primary and metastatic cancers that affect bone are frequently associated with severe and intractable pain. The mechanisms underlying the development of bone cancer pain are largely unknown. The aim of this study was to determine whether enhanced excitability of primary sensory neurons contributed to peripheral sensitization and tumor-induced hyperalgesia during cancer condition. In this study, using techniques of whole-cell patch-clamp recording associated with immunofluorescent staining, single-cell reverse-transcriptase PCR and behavioral test, we investigated whether the intrinsic membrane properties and the excitability of small-sized dorsal root ganglion (DRG) neurons altered in a rat model of bone cancer pain, and whether suppression of DRG neurons activity inhibited the bone cancer-induced pain. Results Our present study showed that implantation of MRMT-1 tumor cells into the tibial canal in rats produced significant mechanical and thermal hyperalgesia in the ipsilateral hind paw. Moreover, implantation of tumor cells provoked spontaneous discharges and tonic excitatory discharges evoked by a depolarizing current pulse in small-sized DRG neurons. In line with these findings, alterations in intrinsic membrane properties that reflect the enhanced neuronal excitability were observed in small DRG neurons in bone cancer rats, of which including: 1) depolarized resting membrane potential (RMP); 2) decreased input resistance (Rin); 3) a marked reduction in current threshold (CT) and voltage threshold (TP) of action potential (AP); 4) a dramatic decrease in amplitude, overshot, and duration of evoked action potentials as well as in amplitude and duration of afterhyperpolarization (AHP); and 5) a significant increase in the firing frequency of evoked action potentials. Here, the decreased AP threshold and increased firing frequency of evoked action potentials implicate the occurrence of hyperexcitability in small-sized DRG neurons in bone cancer rats. In

Dorsal raphe nucleus projecting retinal ganglion cells: Why Y cells?

PubMed Central

Pickard, Gary E.; So, Kwok-Fai; Pu, Mingliang

2015-01-01

Retinal ganglion Y (alpha) cells are found in retinas ranging from frogs to mice to primates. The highly conserved nature of the large, fast conducting retinal Y cell is a testament to its fundamental task, although precisely what this task is remained ill-defined. The recent discovery that Y-alpha retinal ganglion cells send axon collaterals to the serotonergic dorsal raphe nucleus (DRN) in addition to the lateral geniculate nucleus (LGN), medial interlaminar nucleus (MIN), pretectum and the superior colliculus (SC) has offered new insights into the important survival tasks performed by these cells with highly branched axons. We propose that in addition to its role in visual perception, the Y-alpha retinal ganglion cell provides concurrent signals via axon collaterals to the DRN, the major source of serotonergic afferents to the forebrain, to dramatically inhibit 5-HT activity during orientation or alerting/escape responses, which dis-facilitates ongoing tonic motor activity while dis-inhibiting sensory information processing throughout the visual system. The new data provide a fresh view of these evolutionarily old retinal ganglion cells. PMID:26363667

[Effect of high-fat diet on expression of transient receptor potential vanilloid 1 in respiratory tract and dorsal root ganglion of mice].

PubMed

Zhu, Lian; Xu, Zhi-Liang

2017-07-01

To investigate the effect of high-fat diet on the expression of transient receptor potential vanilloid 1 (TRPV1) in the respiratory system and the dorsal root ganglion (DRG) of mice, as well as its effect on the excitability of sensory neurons. A total of 20 C57BL/6 mice were randomly divided into normal-diet (ND) group and high-fat diet (HFD) group, with 10 mice in each group. The mice were given corresponding diets and body weights were monitored. After 7 weeks of feeding, lung tissue, bronchial tissue, and DRG at thoracic segments 3-4 were collected and immunohistochemical staining was performed. A patch clamp was used to measure the number of action potentials and TRPV1 current intensity in the DRG. After 7 weeks of feeding, the HFD group had significantly greater mean weight gain than the ND group (6.4±2.6 g vs 2.3±0.5 g; P<0.001). The HFD group had significantly higher expression of TRPV1 in the bronchus, pulmonary alveoli, and DRG than the ND group (P<0.05). Compared with the ND group, the HFD group had significant increases in the TRPV1 current intensity and number of action potentials in the DRG (P<0.05). High-fat diet induces a significant increase in body weight and leads to high expression of TRPV1 and high excitability in the respiratory system and the peripheral sensory neurons. This suggests that TRPV1 may be an important factor in the physiopathological mechanisms of bronchial hyperresponsiveness.

Demethylation regulation of BDNF gene expression in dorsal root ganglion neurons is implicated in opioid-induced pain hypersensitivity in rats.

PubMed

Chao, Yu-Chieh; Xie, Fang; Li, Xueyang; Guo, Ruijuan; Yang, Ning; Zhang, Chen; Shi, Rong; Guan, Yun; Yue, Yun; Wang, Yun

2016-07-01

Repeated administration of morphine may result in opioid-induced hypersensitivity (OIH), which involves altered expression of numerous genes, including brain-derived neurotrophic factor (BDNF) in dorsal root ganglion (DRG) neurons. Yet, it remains unclear how BDNF expression is increased in DRG neurons after repeated morphine treatment. DNA methylation is an important mechanism of epigenetic control of gene expression. In the current study, we hypothesized that the demethylation regulation of certain BDNF gene promoters in DRG neurons may contribute to the development of OIH. Real-time RT-PCR was used to assess changes in the mRNA transcription levels of major BDNF exons including exon I, II, IV, VI, as well as total BDNF mRNA in DRGs from rats after repeated morphine administration. The levels of exon IV and total BDNF mRNA were significantly upregulated by repeated morphine administration, as compared to that in saline control group. Further, ELISA array and immunocytochemistry study revealed a robust upregulation of BDNF protein expression in DRG neurons after repeated morphine exposure. Correspondingly, the methylation levels of BDNF exon IV promoter showed a significant downregulation by morphine treatment. Importantly, intrathecal administration of a BDNF antibody, but not control IgG, significantly inhibited mechanical hypersensitivity that developed in rats after repeated morphine treatment. Conversely, intrathecal administration of an inhibitor of DNA methylation, 5-aza-2'-deoxycytidine (5-aza-dC) markedly upregulated the BDNF protein expression in DRG neurons and enhanced the mechanical allodynia after repeated morphine exposure. Together, our findings suggest that demethylation regulation of BDNF gene promoter may be implicated in the development of OIH through epigenetic control of BDNF expression in DRG neurons. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effects of neuroleptics on the GABA-induced Cl- current in rat dorsal root ganglion neurons: differences between some neuroleptics.

PubMed

Yokota, Kenjiro; Tatebayashi, Hideharu; Matsuo, Tadashi; Shoge, Takashi; Motomura, Haruhiko; Matsuno, Toshiyuki; Fukuda, Akira; Tashiro, Nobutada

2002-03-01

1. Several neuroleptics inhibited the 3 microM gamma-aminobutyric acid induced-chloride current (GABA-current) on dissociated rat dorsal root ganglion neurons in whole-cell patch-clamp investigations. 2. The IC(50) for clozapine, zotepine, olanzapine, risperidone and chlorpromazine were 6.95, 18.26, 20.30, 106.01 and 114.56 microM, respectively. The values for the inhibitory effects of neuroleptics on the GABA (3 microM)-current, which were calculated by the fitting Hill's equations where the concentrations represent the mean therapeutic blood concentrations, were ranked clozapine>zotepine>chlorpromazine>olanzapine>risperidone. These inhibitory effects, weighted with the therapeutic concentrations of neuroleptics, were correlated with the clinical incidences of seizure during treatment with neuroleptics. 3. Clozapine reduced the picrotoxin-inhibiton, and may compete with a ligand of the t-butylbicyclophosphorothionate (TBPS) binding site. 4. Haloperidol and quetiapine did not affect the peak amplitude of the GABA (3 microM)-current. However, haloperidol reduced the clozapine-inhibition, and may antagonize ligand binding to TBPS binding site. 5. Neuroleptics including haloperidol and quetiapine enhanced the desensitization of the GABA (3 microM)-current. However, haloperidol and quetiapine at 100 microM inhibited the desensitization at the beginning of application. 6. Blonanserin (AD-5423) at 30 and 50 microM potentiated the GABA (3 microM)-current to 170.1+/-6.9 and 192.0+/-10.6% of the control current, respectively. Blonanserin shifted GABA concentration-response curve leftward. Blonanserin only partly negatively interacted with diazepam. The blonanserin-potentiation was not reversed by flumazenil. Blonanserin is not a benzodiazepine receptor agonist. 7. The various effects of neuroleptics on the GABA-current may be related to the clinical effects including modifying the seizure threshold.

The effects of neuroleptics on the GABA-induced Cl− current in rat dorsal root ganglion neurons: differences between some neuroleptics

PubMed Central

Yokota, Kenjiro; Tatebayashi, Hideharu; Matsuo, Tadashi; Shoge, Takashi; Motomura, Haruhiko; Matsuno, Toshiyuki; Fukuda, Akira; Tashiro, Nobutada

2002-01-01

Several neuroleptics inhibited the 3 μM γ-aminobutyric acid induced-chloride current (GABA-current) on dissociated rat dorsal root ganglion neurons in whole-cell patch-clamp investigations. The IC50 for clozapine, zotepine, olanzapine, risperidone and chlorpromazine were 6.95, 18.26, 20.30, 106.01 and 114.56 μM, respectively. The values for the inhibitory effects of neuroleptics on the GABA (3 μM)-current, which were calculated by the fitting Hill's equations where the concentrations represent the mean therapeutic blood concentrations, were ranked clozapine>zotepine>chlorpromazine>olanzapine>risperidone. These inhibitory effects, weighted with the therapeutic concentrations of neuroleptics, were correlated with the clinical incidences of seizure during treatment with neuroleptics. Clozapine reduced the picrotoxin-inhibiton, and may compete with a ligand of the t-butylbicyclophosphorothionate (TBPS) binding site. Haloperidol and quetiapine did not affect the peak amplitude of the GABA (3 μM)-current. However, haloperidol reduced the clozapine-inhibition, and may antagonize ligand binding to TBPS binding site. Neuroleptics including haloperidol and quetiapine enhanced the desensitization of the GABA (3 μM)-current. However, haloperidol and quetiapine at 100 μM inhibited the desensitization at the beginning of application. Blonanserin (AD-5423) at 30 and 50 μM potentiated the GABA (3 μM)-current to 170.1±6.9 and 192.0±10.6% of the control current, respectively. Blonanserin shifted GABA concentration-response curve leftward. Blonanserin only partly negatively interacted with diazepam. The blonanserin-potentiation was not reversed by flumazenil. Blonanserin is not a benzodiazepine receptor agonist. The various effects of neuroleptics on the GABA-current may be related to the clinical effects including modifying the seizure threshold. PMID:11906969

Activation of KCNQ Channels Suppresses Spontaneous Activity in Dorsal Root Ganglion Neurons and Reduces Chronic Pain after Spinal Cord Injury

PubMed Central

Wu, Zizhen; Li, Lin; Xie, Fuhua; Du, Junhui; Zuo, Yan; Frost, Jeffrey A.; Carlton, Susan M.; Walters, Edgar T.

2017-01-01

Abstract A majority of people who have sustained spinal cord injury (SCI) experience chronic pain after injury, and this pain is highly resistant to available treatments. Contusive SCI in rats at T10 results in hyperexcitability of primary sensory neurons, which contributes to chronic pain. KCNQ channels are widely expressed in nociceptive dorsal root ganglion (DRG) neurons, are important for controlling their excitability, and their activation has proven effective in reducing pain in peripheral nerve injury and inflammation models. The possibility that activators of KCNQ channels could be useful for treating SCI-induced chronic pain is strongly supported by the following findings. First, SCI, unlike peripheral nerve injury, failed to decrease the functional or biochemical expression of KCNQ channels in DRG as revealed by electrophysiology, real-time quantitative polymerase chain reaction, and Western blot; therefore, these channels remain available for pharmacological targeting of SCI pain. Second, treatment with retigabine, a specific KCNQ channel opener, profoundly decreased spontaneous activity in primary sensory neurons of SCI animals both in vitro and in vivo without changing the peripheral mechanical threshold. Third, retigabine reversed SCI-induced reflex hypersensitivity, adding to our previous demonstration that retigabine supports the conditioning of place preference after SCI (an operant measure of spontaneous pain). In contrast to SCI animals, naïve animals showed no effects of retigabine on reflex sensitivity or conditioned place preference by pairing with retigabine, indicating that a dose that blocks chronic pain-related behavior has no effect on normal pain sensitivity or motivational state. These results encourage the further exploration of U.S. Food and Drug Administration–approved KCNQ activators for treating SCI pain, as well as efforts to develop a new generation of KCNQ activators that lack central side effects. PMID:28073317

Activation of KCNQ Channels Suppresses Spontaneous Activity in Dorsal Root Ganglion Neurons and Reduces Chronic Pain after Spinal Cord Injury.

PubMed

Wu, Zizhen; Li, Lin; Xie, Fuhua; Du, Junhui; Zuo, Yan; Frost, Jeffrey A; Carlton, Susan M; Walters, Edgar T; Yang, Qing

2017-03-15

A majority of people who have sustained spinal cord injury (SCI) experience chronic pain after injury, and this pain is highly resistant to available treatments. Contusive SCI in rats at T10 results in hyperexcitability of primary sensory neurons, which contributes to chronic pain. KCNQ channels are widely expressed in nociceptive dorsal root ganglion (DRG) neurons, are important for controlling their excitability, and their activation has proven effective in reducing pain in peripheral nerve injury and inflammation models. The possibility that activators of KCNQ channels could be useful for treating SCI-induced chronic pain is strongly supported by the following findings. First, SCI, unlike peripheral nerve injury, failed to decrease the functional or biochemical expression of KCNQ channels in DRG as revealed by electrophysiology, real-time quantitative polymerase chain reaction, and Western blot; therefore, these channels remain available for pharmacological targeting of SCI pain. Second, treatment with retigabine, a specific KCNQ channel opener, profoundly decreased spontaneous activity in primary sensory neurons of SCI animals both in vitro and in vivo without changing the peripheral mechanical threshold. Third, retigabine reversed SCI-induced reflex hypersensitivity, adding to our previous demonstration that retigabine supports the conditioning of place preference after SCI (an operant measure of spontaneous pain). In contrast to SCI animals, naïve animals showed no effects of retigabine on reflex sensitivity or conditioned place preference by pairing with retigabine, indicating that a dose that blocks chronic pain-related behavior has no effect on normal pain sensitivity or motivational state. These results encourage the further exploration of U.S. Food and Drug Administration-approved KCNQ activators for treating SCI pain, as well as efforts to develop a new generation of KCNQ activators that lack central side effects.

[Ganglions of the wrist: proposals for topographical systematization and natural history].

PubMed

Kuhlmann, J-N; Luboinski, J; Baux, S; Mimoun, M

2003-06-01

We looked for the anatomic origin and mechanism of constitution of the so-called "ganglions" of the wrist. Fifty-nine formations considered to be synovial ganglions were dissected and removed according to the same protocol by the same surgeon. Eleven were re-examined by a pathologist. All ganglions were extra-articular but had intra- and extra-capsular components. The extra-capsular part was the clinically palpable main cyst. The intra-capsular part was composed of the cystic stalk and its base of implantation. An intra-capsular stalk was present in 58 cases. The stalk was situated between the joint synovium and the capsula which it perforated at a weak point between two ligaments, forming a collar before expanding outwardly. Based on our findings, we propose a topographical systematization and natural history of ganglions of the wrist. The stalk's implantation base was always located on bone and found in the intermediate area of Colomniati and Soubbotine, which lies outside the articular cartilage between the synovium and the ligamentous capsula. This area is exposed to mechanical stress initiating histological degenerative lesions, particularly mucoid degeneration. At the radiocarpal joint, the stalk's base of implantation was located at the distal end of the lateral dorsal or volar edge of the lunate bone or at the corresponding part of the scaphoid. The collar of the proximal ganglions was situated between the dorsal radiocarpal and transverse scaphotriquetral ligament. The collar of distal dorsal ganglions was situated between the transverse scaphotriquetral and the trapezotriquetral ligament. The collar of the lateral ganglions was situated between the lateral collateral and the transverse ligament. The collar of the volar ganglions was situated between the stylocarpal ligament and the radiolunotriquetral ligament, or between the different stylocarpal ligaments. At the level of the scaphotrapezal joint, the stalk's base of implantation was located near the

[Influence of acupunction on NT-4 expression in spared root ganglion and spinal cord].

PubMed

Long, Shuang-Lian; Liu, Fen; Wang, Ting-Hua; Wang, Te-Wei; Ke, Qing; Yuan, Yuan

2005-09-01

To explore the changes of the expression of NT-4 in spared dorsal root ganglia (DRG,L6) on both the operation/Acup side and the nonoperation/non-Acup side as well as in the spinal lamina II (L3, L5, L6) and Clarke' nucleus (L3) of the normal adult cats, partial dorsal rhizotomy cats, and Acup spared DRG cats so as to disclose the relation between NT-4 and the plasticity of spinal cord as well as the Acup promoting spinal cord plasticity. Twenty-five adult cats were divided into 5 groups; normal control group; unilateral partial root rhizotomy 7 d and 14 d groups (unilateral L1-L5, L7-S2 DRG were transected, but L6 DRG was spared); Acup spared DRG 7 d and 14 d groups (electro-needle stimulation was performed following unilateral partial root rhizotomy). The cats survived for 7 or 14 days after operation respectively. Bilateral L6 dorsal root ganglia and L3, L5, L6 spinal cord of every group were made into 20 microm frozen sections. Then, sections were stained under the same condition using specific NT-4 (1 : 200) antibody by the immunohistochemistry ABC method. The distribution and the number of NT-4 immunoreactive neurons in bilateral spared DRG (L6) on the operation/Acup side and the nonoperation/Acup side as well as in the, spinal lamina II (L3, L5, L6) and Clarke' nucleus (L3) of each cat were oberserved and counted. All data were analyzed by one-way ANOVA, SNK-q test and paired-t test. Partial dorsal root rhizotomy led to continuous declination of total NT-4 immunoreactive neurons in spared ganglia, till the 14 d, while Acup reversed this tendency and made NT-4 immunoreactive neurons decrease firstly and then approach to normal level till the 14 d after Acup. In addition, Acup increased NT-4 expression in L5, L6 spinal lamina II. The above finding indicate that NT-4 plays an important role in the mechanism by which Acup promotes spinal cord plasticity. Partial dorsal root rhizotomy and Acup spared DRG may exert effects on the expression of NT-4 in the

Differentiation of oligodendrocyte progenitor cells from dissociated monolayer and feeder-free cultured pluripotent stem cells.

PubMed

Yamashita, Tomoko; Miyamoto, Yuki; Bando, Yoshio; Ono, Takashi; Kobayashi, Sakurako; Doi, Ayano; Araki, Toshihiro; Kato, Yosuke; Shirakawa, Takayuki; Suzuki, Yutaka; Yamauchi, Junji; Yoshida, Shigetaka; Sato, Naoya

2017-01-01

Oligodendrocytes myelinate axons and form myelin sheaths in the central nervous system. The development of therapies for demyelinating diseases, including multiple sclerosis and leukodystrophies, is a challenge because the pathogenic mechanisms of disease remain poorly understood. Primate pluripotent stem cell-derived oligodendrocytes are expected to help elucidate the molecular pathogenesis of these diseases. Oligodendrocytes have been successfully differentiated from human pluripotent stem cells. However, it is challenging to prepare large amounts of oligodendrocytes over a short amount of time because of manipulation difficulties under conventional primate pluripotent stem cell culture methods. We developed a proprietary dissociated monolayer and feeder-free culture system to handle pluripotent stem cell cultures. Because the dissociated monolayer and feeder-free culture system improves the quality and growth of primate pluripotent stem cells, these cells could potentially be differentiated into any desired functional cells and consistently cultured in large-scale conditions. In the current study, oligodendrocyte progenitor cells and mature oligodendrocytes were generated within three months from monkey embryonic stem cells. The embryonic stem cell-derived oligodendrocytes exhibited in vitro myelinogenic potency with rat dorsal root ganglion neurons. Additionally, the transplanted oligodendrocyte progenitor cells differentiated into myelin basic protein-positive mature oligodendrocytes in the mouse corpus callosum. This preparative method was used for human induced pluripotent stem cells, which were also successfully differentiated into oligodendrocyte progenitor cells and mature oligodendrocytes that were capable of myelinating rat dorsal root ganglion neurons. Moreover, it was possible to freeze, thaw, and successfully re-culture the differentiating cells. These results showed that embryonic stem cells and human induced pluripotent stem cells maintained in a

Neuroprotection by GH against excitotoxic-induced cell death in retinal ganglion cells.

PubMed

Martínez-Moreno, Carlos G; Ávila-Mendoza, José; Wu, Yilun; Arellanes-Licea, Elvira Del Carmen; Louie, Marcela; Luna, Maricela; Arámburo, Carlos; Harvey, Steve

2016-08-01

Retinal growth hormone (GH) has been shown to promote cell survival in retinal ganglion cells (RGCs) during developmental waves of apoptosis during chicken embryonic development. The possibility that it might also against excitotoxicity-induced cell death was therefore examined in the present study, which utilized quail-derived QNR/D cells as an in vitro RGC model. QNR/D cell death was induced by glutamate in the presence of BSO (buthionine sulfoxamide) (an enhancer of oxidative stress), but this was significantly reduced (P<0.01) in the presence of exogenous recombinant chicken GH (rcGH). Similarly, QNR/D cells that had been prior transfected with a GH plasmid to overexpress secreted and non-secreted GH. This treatment reduced the number of TUNEL-labeled cells and blocked their release of lactate dehydrogenase (LDH). In a further experiment with dissected neuroretinal explants from ED (embryonic day) 10 embryos, rcGH treatment of the explants also reduced (P<0.01) the number of glutamate-BSO-induced apoptotic cells and blocked the explant release of LDH. This neuroprotective action was likely mediated by increased STAT5 phosphorylation and increased bcl-2 production, as induced by exogenous rcGH treatment and the media from GH-overexpressing QNR/D cells. As rcGH treatment and GH-overexpression cells also increased the content of IGF-1 and IGF-1 mRNA this neuroprotective action of GH is likely to be mediated, at least partially, through an IGF-1 mechanism. This possibility is supported by the fact that the siRNA knockdown of GH or IGF-1 significantly reduced QNR/D cell viability, as did the immunoneutralization of IGF-1. GH is therefore neuroprotective against excitotoxicity-induced RGC cell death by anti-apoptotic actions involving IGF-1 stimulation. Copyright © 2016 Elsevier Inc. All rights reserved.

Calcium channels in solitary retinal ganglion cells from post-natal rat.

PubMed Central

Karschin, A; Lipton, S A

1989-01-01

1. Calcium currents from identified, post-natal retinal ganglion cell neurones from rat were studied with whole-cell and single-channel patch-clamp techniques. Na+ and K+ currents were suppressed with pharmacological agents, allowing isolation of current carried by either 10 mM-Ca2+ or Ba2- during whole-cell recordings. For cell-attached patch recordings, the recording pipette contained 96-110 mM-BaCl2 while the bath solution consisted of isotonic potassium aspartate in order to zero the neuronal membrane potential. 2. A transient component, present in approximately one-third of the whole-cell recordings resembles closely the T-type calcium current observed previously in other tissues. This component activates at low voltages (-40 to -50 mV from holding potentials negative to -80 mV), inactivates with a time constant of 10-30 ms at 35 degrees C, and is carried equally well by Ba2+ or Ca2+. In single-channel recordings small (8 pS) channels are observed whose aggregate microscopic kinetics correspond well to the macroscopic current obtained during whole-cell measurements. 3. During whole-cell recordings, a more prolonged component activates in all retinal ganglion cells at -40 to -20 mV from a holding potential of -90 mV. This component is substantially larger when equimolar Ba2+ replaces Ca2+ as the charge carrier, and is sensitive to the dihydropyridine agonist Bay K8644 (5 microM) and antagonists nifedipine (1-10 microM) and nimodipine (1-10 microM). Thus, the dihydropyridine pharmacology of this prolonged component resembles that of the L-type calcium current found in dorsal root ganglion neurones and in heart cells. Also reminiscent of the L-current, the prolonged component in this preparation is less inactivated at depolarized holding potentials (-60 to -40 mV) than the transient component. In cell-attached recordings, large (20 pS) channels are observed with activation properties similar to those of the prolonged portion of the whole-cell current. 4. omega

Quercetin protects rat dorsal root ganglion neurons against high glucose-induced injury in vitro through Nrf-2/HO-1 activation and NF-κB inhibition.

PubMed

Shi, Yue; Liang, Xiao-chun; Zhang, Hong; Wu, Qun-li; Qu, Ling; Sun, Qing

2013-09-01

To examine the effects of quercetin, a natural antioxidant, on high glucose (HG)-induced apoptosis of cultured dorsal root ganglion (DRG) neurons of rats. DRG neurons exposed to HG (45 mmol/L) for 24 h were employed as an in vitro model of diabetic neuropathy. Cell viability, reactive oxygen species (ROS) level and apoptosis were determined. The expression of NF-кB, IкBα, phosphorylated IкBα and Nrf2 was examined using RT PCR and Western blot assay. The expression of hemeoxygenase-1 (HO-1), IL-6, TNF-α, iNOS, COX-2, and caspase-3 were also examined. HG treatment markedly increased DRG neuron apoptosis via increasing intracellular ROS level and activating the NF-κB signaling pathway. Co-treatment with quercetin (2.5, 5, and 10 mmol/L) dose-dependently decreased HG-induced caspase-3 activation and apoptosis. Quercetin could directly scavenge ROS and significantly increased the expression of Nrf-2 and HO-1 in DRG neurons. Quercetin also dose-dependently inhibited the NF-κB signaling pathway and suppressed the expression of iNOS, COX-2, and proinflammatory cytokines IL-6 and TNF-α. Quercetin protects rat DRG neurons against HG-induced injury in vitro through Nrf-2/HO-1 activation and NF-κB inhibition, thus may be beneficial for the treatment of diabetic neuropathy.

Strychnine blocks transient but not sustained inhibition in mudpuppy retinal ganglion cells.

PubMed Central

Belgum, J H; Dvorak, D R; McReynolds, J S

1984-01-01

Transient and sustained inhibitory synaptic inputs to on-centre, off-centre, and on-off ganglion cells in the mudpuppy retina were studied using intracellular recording in the superfused eye-cup preparation. When chemical transmission was blocked with 4 mM-Co2+, application of either glycine or gamma-aminobutyric acid (GABA) caused a hyperpolarization and conductance increase in all ganglion cells. For both amino acids, the responses were dose dependent in the range 0.05-10 mM, with a half-maximal response at about 0.7 mM. Glycine and GABA sensitivities were very similar in all three types of ganglion cells. The response to applied glycine was selectively antagonized by 10(-5) M-strychnine and the response to applied GABA was selectively antagonized by 10(-5) M-picrotoxin. In all ganglion cells, 10(-5) M-strychnine eliminated the transient inhibitory events which occur at the onset and termination of a light stimulus. The block of transient inhibition was associated with a relative depolarization of membrane potential and decrease in conductance at these times. Strychnine had no effect on membrane potential or conductance in darkness or during sustained inhibitory responses to light. Picrotoxin (10(-5) M) did not block transient inhibitory events in any ganglion cells, but did affect other components of their responses. The results suggest that in all three classes of ganglion cells transient inhibition, but not sustained inhibition, may be mediated by glycine or a closely related substance. PMID:6481635

Teratogenic Effects of Pyridoxine on the Spinal Cord and Dorsal Root Ganglia of Embryonic Chickens

PubMed Central

Sharp, Andrew A.; Fedorovich, Yuri

2015-01-01

Our understanding of the role of somatosensory feedback in regulating motility during chicken embryogenesis and fetal development in general has been hampered by the lack of an approach to selectively alter specific sensory modalities. In adult mammals, pyridoxine overdose has been shown to cause a peripheral sensory neuropathy characterized by a loss of both muscle and cutaneous afferents, but predominated by a loss of proprioception. We have begun to explore the sensitivity of the nervous system in chicken embryos to the application of pyridoxine on embryonic days 7 and 8, after sensory neurons in the lumbosacral region become post-mitotic. Upon examination of the spinal cord, DRG and peripheral nerves, we find that pyridoxine causes a loss of TrkC-positive neurons, a decrease in the diameter of the muscle innervating nerve tibialis, and a reduction in the number of large diameter axons in this nerve. However, we found no change in the number of Substance P or CGRP-positive neurons, the number of motor neurons or the diameter or axonal composition of the femoral cutaneous nerve. Therefore, pyridoxine causes a peripheral sensory neuropathy in embryonic chickens largely consistent with its effects in adult mammals. However, the lesion may be more restricted to proprioception in the chicken embryo. Therefore, pyridoxine lesion induced during embryogenesis in the chicken embryo can be used to asses how the loss of sensation, largely proprioception, alters spontaneous embryonic motility and subsequent motor development. PMID:25592428

Cell wall properties play an important role in the emergence of lateral root primordia from the parent root.

PubMed

Roycewicz, Peter S; Malamy, Jocelyn E

2014-05-01

Plants adapt to their unique soil environments by altering the number and placement of lateral roots post-embryonic. Mutants were identified in Arabidopsis thaliana that exhibit increased lateral root formation. Eight mutants were characterized in detail and were found to have increased lateral root formation due to at least three distinct mechanisms. The causal mutation in one of these mutants was found in the XEG113 gene, recently shown to be involved in plant cell wall biosynthesis. Lateral root primordia initiation is unaltered in this mutant. In contrast, synchronization of lateral root initiation demonstrated that mutation of XEG113 increases the rate at which lateral root primordia develop and emerge to form lateral roots. The effect of the XEG113 mutation was specific to the root system and had no apparent effect on shoot growth. Screening of 17 additional cell wall mutants, altering a myriad of cell wall components, revealed that many (but not all) types of cell wall defects promote lateral root formation. These results suggest that proper cell wall biosynthesis is necessary to constrain lateral root primordia emergence. While previous reports have shown that lateral root emergence is accompanied by active remodelling of cell walls overlying the primordia, this study is the first to demonstrate that alteration of the cell wall is sufficient to promote lateral root formation. Therefore, inherent cell wall properties may play a previously unappreciated role in regulation of root system architecture.

Hedgehog Is a Positive Regulator of FGF Signalling during Embryonic Tracheal Cell Migration

PubMed Central

Butí, Elisenda; Mesquita, Duarte; Araújo, Sofia J.

2014-01-01

Cell migration is a widespread and complex process that is crucial for morphogenesis and for the underlying invasion and metastasis of human cancers. During migration, cells are steered toward target sites by guidance molecules that induce cell direction and movement through complex intracellular mechanisms. The spatio-temporal regulation of the expression of these guidance molecules is of extreme importance for both normal morphogenesis and human disease. One way to achieve this precise regulation is by combinatorial inputs of different transcription factors. Here we used Drosophila melanogaster mutants with migration defects in the ganglionic branches of the tracheal system to further clarify guidance regulation during cell migration. By studying the cellular consequences of overactivated Hh signalling, using ptc mutants, we found that Hh positively regulates Bnl/FGF levels during embryonic stages. Our results show that Hh modulates cell migration non-autonomously in the tissues surrounding the action of its activity. We further demonstrate that the Hh signalling pathway regulates bnl expression via Stripe (Sr), a zinc-finger transcription factor with homology to the Early Growth Response (EGR) family of vertebrate transcription factors. We propose that Hh modulates embryonic cell migration by participating in the spatio-temporal regulation of bnl expression in a permissive mode. By doing so, we provide a molecular link between the activation of Hh signalling and increased chemotactic responses during cell migration. PMID:24651658

Hedgehog is a positive regulator of FGF signalling during embryonic tracheal cell migration.

PubMed

Butí, Elisenda; Mesquita, Duarte; Araújo, Sofia J

2014-01-01

Cell migration is a widespread and complex process that is crucial for morphogenesis and for the underlying invasion and metastasis of human cancers. During migration, cells are steered toward target sites by guidance molecules that induce cell direction and movement through complex intracellular mechanisms. The spatio-temporal regulation of the expression of these guidance molecules is of extreme importance for both normal morphogenesis and human disease. One way to achieve this precise regulation is by combinatorial inputs of different transcription factors. Here we used Drosophila melanogaster mutants with migration defects in the ganglionic branches of the tracheal system to further clarify guidance regulation during cell migration. By studying the cellular consequences of overactivated Hh signalling, using ptc mutants, we found that Hh positively regulates Bnl/FGF levels during embryonic stages. Our results show that Hh modulates cell migration non-autonomously in the tissues surrounding the action of its activity. We further demonstrate that the Hh signalling pathway regulates bnl expression via Stripe (Sr), a zinc-finger transcription factor with homology to the Early Growth Response (EGR) family of vertebrate transcription factors. We propose that Hh modulates embryonic cell migration by participating in the spatio-temporal regulation of bnl expression in a permissive mode. By doing so, we provide a molecular link between the activation of Hh signalling and increased chemotactic responses during cell migration.

A family of glycoproteins (GP55), which inhibit neurite outgrowth, are members of the Ig superfamily and are related to OBCAM, neurotrimin, LAMP and CEPU-1.

PubMed

Wilson, D J; Kim, D S; Clarke, G A; Marshall-Clarke, S; Moss, D J

1996-12-01

We have previously identified a glycosylphosphatidylinositol-linked glycoprotein of 55 kDa (GP55) which inhibits neurite outgrowth. We now provide evidence that GP55, isolated from adult chick brain, consists of at least two bands, both of which are active, i.e., block outgrowth of neurites from chick dorsal root ganglion neurons. An antiserum raised against the adult proteins reverses the inhibition and preliminary experiments suggest that GP55 is restricted to the nervous system, increases during development from very low levels at embryonic day 10 and is most abundant after hatching. Immunofluorescence reveals that GP55 is expressed on neurons cultured from an embryonic day 14 chick brain but is barely detectable on embryonic day 10 dorsal root ganglion neurons or embryonic day 8 forebrain neurons; the neurons which respond to substrate-bound GP55. Peptide sequencing revealed considerable homology with OBCAM, a protein previously identified on the basis of binding opiates. Nested polymerase chain reaction using primers to the OBCAM sequence and internal primers to GP55 peptides produced two different polymerase chain reaction fragments with homology to OBCAM. A full length clone (E19S) corresponding to one polymerase chain reaction product and a partial length clone (E14S) corresponding to the second have been isolated from an embryonic chick brain library. Both are members of the immunoglobulin superfamily and have (or are expected to have) three C2 domains. E19S has 90% homology with LAMP at the amino acid level. This sequence only partially matches the peptides from the adult protein and hence is probably not a major component of the adult proteins. E14S (GP55-A) has 83% homology to OBCAM at the amino acid level over the region sequenced. The sequence matches several of the peptides from the adult protein and is hence likely to correspond to a major component of the adult proteins. Thus members of the GP55 family are related to OBCAM, neurotrimin, LAMP and a

Forced treadmill running suppresses postincisional pain and inhibits upregulation of substance P and cytokines in rat dorsal root ganglion.

PubMed

Chen, Yu-Wen; Tzeng, Jann-Inn; Lin, Min-Fei; Hung, Ching-Hsia; Wang, Jhi-Joung

2014-08-01

Exercise causes a variety of psychophysical effects (eg, alterations in pain sensation). Tissue injury induces mediator releases in the spinal cord resulting in pain hypersensitivity; however, the contribution of the dorsal root ganglion (DRG) is poorly understood. In this study, we tested if forced treadmill running can attenuate postoperative pain and alter substance P (SP) or proinflammatory cytokine level in the DRG by using a rat model of skin/muscle incision and retraction (SMIR). We evaluated mechanical sensitivity to von Frey stimuli (6 and 15 g) and expression of SP, interleukin-1β, and interleukin-6 in the DRG of sham-operated sedentary rats, SMIR sedentary rats, sham-operated rats with forced treadmill running, and SMIR rats with forced treadmill running. At postoperative day 8, trained rats ran for 5 days per week for 4 weeks on a treadmill 70 minutes/d with an intensity of 18 m/min. On postoperative day 6, SMIR sedentary rats displayed a significant mechanical hypersensitivity that persisted until postoperative day 35. By comparison, SMIR-operated rats, which received forced treadmill running, exhibited a quick recovery from mechanical hypersensitivity. SMIR sedentary rats showed an upregulation of SP, interleukin-1β, and interleukin-6 in the DRG at postoperative days 14 and 28, whereas SMIR-operated rats receiving forced treadmill running reversed this upregulation at postoperative day 28. We concluded that forced treadmill running alleviated persistent postincisional pain caused by SMIR surgery. This appears to be protective against postoperative pain, which probably relates to the downturn in excess SP, interleukin-1β, and interleukin-6 in the DRG. Controlling the expression of SP, interleukin-6, and interleukin-1β in the DRG can help manage postoperative pain. This finding could potentially help clinicians and physical therapists who seek to examine how exercise may attenuate postsurgical pain and its mechanism. Copyright © 2014 American Pain

[Effects of small needle knife on the substance P in the dorsal root ganglion and spinal cord of rats].

PubMed

Wang, Jin-Rong; Wang, Yong-Zhi; Dong, Fu-Hui; Zhong, Hong-Gang; Wang, De-Long; Wang, Xuan

2010-09-01

To study the mechanism of synthesis of substance P (SP) in the dorsal root ganglion (DRG) and the release of it in the dorsal horn of the spinal cord of rats after compression of skeletal muscle, and to observe the influence of small needle knife. Sustained pressure of 70 kPa was applied to rats, muscular tissues for 2 hours. The rats were divided into three groups: normal, control and experiment group respectively. In all rats except the six normal ones, the lower legs were compressed once one day. The left leg was considered as the control group, the right left was experiment group, which were divided into the 1st day, the 2nd day and the 3rd day within the two groups. Experiment group was treated with small needle knife after the muscular tissue was compressed. After completing the stimulation, the DRG related to the muscle and part of spinal cord were removed for the qualification of SP-like immunoreactivity using immunohistochemistry. The dark brown stains on the DRG and on the REXed laminae I and II in the dorsal horn of the spinal cord were counted by Image-Pro Plus software. SP-like immunoreactivity in the side treated by the small needle knife was enhanced comparing with the counterpart in DRG in normal group (P < 0.01). The integrated optical density of SP like immunoreactivity of the DRG in the experiment group were significantly reduced compared with the control group (P < 0.05). However, the release of SP from spinal cord in experiment group was lower than that in the control group at the 1st day and the 3rd day (P < 0.01), with the opposite result of the 2nd day. Based on the fact that SP is a nociceptive neurotransmitter, the present study suggests that tension relaxation by small needle knife reduces expression of SP in the DRG, and shows no effects on the release of SP from the spinal cord in short-term (3 days).

Quantifying Spiral Ganglion Neurite and Schwann Behavior on Micropatterned Polymer Substrates.

PubMed

Cheng, Elise L; Leigh, Braden; Guymon, C Allan; Hansen, Marlan R

2016-01-01

The first successful in vitro experiments on the cochlea were conducted in 1928 by Honor Fell (Fell, Arch Exp Zellforsch 7(1):69-81, 1928). Since then, techniques for culture of this tissue have been refined, and dissociated primary culture of the spiral ganglion has become a widely accepted in vitro model for studying nerve damage and regeneration in the cochlea. Additionally, patterned substrates have been developed that facilitate and direct neural outgrowth. A number of automated and semi-automated methods for quantifying this neurite outgrowth have been utilized in recent years (Zhang et al., J Neurosci Methods 160(1):149-162, 2007; Tapias et al., Neurobiol Dis 54:158-168, 2013). Here, we describe a method to study the effect of topographical cues on spiral ganglion neurite and Schwann cell alignment. We discuss our microfabrication process, characterization of pattern features, cell culture techniques for both spiral ganglion neurons and spiral ganglion Schwann cells. In addition, we describe protocols for reducing fibroblast count, immunocytochemistry, and methods for quantifying neurite and Schwann cell alignment.

Guidance of dorsal root ganglion neurites and Schwann cells by isolated Schwann cell topography on poly(dimethyl siloxane) conduits and films

NASA Astrophysics Data System (ADS)

Richardson, J. A.; Rementer, C. W.; Bruder, Jan M.; Hoffman-Kim, D.

2011-08-01

Biomimetic replicas of cellular topography have been utilized to direct neurite outgrowth. Here, we cultured postnatal rat dorsal root ganglion (DRG) explants in the presence of Schwann cell (SC) topography to determine the influence of SC topography on neurite outgrowth. Four distinct poly(dimethyl siloxane) conduits were fabricated within which DRG explants were cultured. To determine the contribution of SC topographical features to neurite guidance, the extent of neurite outgrowth into unpatterned conduits, conduits with randomly oriented SC replicas, and conduits with SC replicas parallel or perpendicular to the conduit long axis was measured. Neurite directionality and outgrowth from DRG were also quantified on two-dimensional SC replicas with orientations corresponding to the four conduit conditions. Additionally, live SC migration and neurite extension from DRG on SC replicas were examined as a first step toward quantification of the interactions between live SC and navigating neurites on SC replicas. DRG neurite outgrowth and morphology within conduits and on two-dimensional SC replicas were directed by the underlying SC topographical features. Maximal neurite outgrowth and alignment to the underlying features were observed into parallel conduits and on parallel two-dimensional substrates, whereas the least extent of outgrowth was observed into perpendicular conduits and on perpendicular two-dimensional replica conditions. Additionally, neurites on perpendicular conditions turned to extend along the direction of underlying SC topography. Neurite outgrowth exceeded SC migration in the direction of the underlying anisotropic SC replica after two days in culture. This finding confirms the critical role that SC have in guiding neurite outgrowth and suggests that the mechanism of neurite alignment to SC replicas depends on direct contact with cellular topography. These results suggest that SC topographical replicas may be used to direct and optimize neurite

[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.

Neurotoxicity of cytarabine (Ara-C) in dorsal root ganglion neurons originates from impediment of mtDNA synthesis and compromise of mitochondrial function.

PubMed

Zhuo, Ming; Gorgun, Murat F; Englander, Ella W

2018-06-01

Peripheral Nervous System (PNS) neurotoxicity caused by cancer drugs hinders attainment of chemotherapy goals. Due to leakiness of the blood nerve barrier, circulating chemotherapeutic drugs reach PNS neurons and adversely affect their function. Chemotherapeutic drugs are designed to target dividing cancer cells and mechanisms underlying their toxicity in postmitotic neurons remain to be fully clarified. The objective of this work was to elucidate progression of events triggered by antimitotic drugs in postmitotic neurons. For proof of mechanism study, we chose cytarabine (ara-C), an antimetabolite used in treatment of hematological cancers. Ara-C is a cytosine analog that terminates DNA synthesis. To investigate how ara-C affects postmitotic neurons, which replicate mitochondrial but not genomic DNA, we adapted a model of Dorsal Root Ganglion (DRG) neurons. We showed that DNA polymerase γ, which is responsible for mtDNA synthesis, is inhibited by ara-C and that sublethal ara-C exposure of DRG neurons leads to reduction in mtDNA content, ROS generation, oxidative mtDNA damage formation, compromised mitochondrial respiration and diminution of NADPH and GSH stores, as well as, activation of the DNA damage response. Hence, it is plausible that in ara-C exposed DRG neurons, ROS amplified by the high mitochondrial content shifts from physiologic to pathologic levels signaling stress to the nucleus. Combined, the findings suggest that ara-C neurotoxicity in DRG neurons originates in mitochondria and that continuous mtDNA synthesis and reliance on oxidative phosphorylation for energy needs sensitize the highly metabolic neurons to injury by mtDNA synthesis terminating cancer drugs. Copyright © 2018 Elsevier Inc. All rights reserved.

The nervus terminalis ganglion in Anguilla rostrata: an immunocytochemical and HRP histochemical analysis.

PubMed

Grober, M S; Bass, A H; Burd, G; Marchaterre, M A; Segil, N; Scholz, K; Hodgson, T

1987-12-08

Immunocytochemistry and retrograde horseradish peroxidase (HRP) transport were used to study the ganglion of the nervus terminalis in the American eel, Anguilla rostrata. Luteinizing hormone releasing hormone (LHRH) like immunoreactivity was found in large, ganglion-like cells located ventromedially at the junction of the telencephalon and olfactory bulb and in fibers within the retina and olfactory epithelium. HRP transport from the retina demonstrated direct connections with both the ipsi- and contralateral populations of these ganglion-like cells. Given the well-documented role of both olfaction and vision during migratory and reproductive phases of the life cycle of eels, the robust nature of a nervus terminalis system in these fish may present a unique opportunity to study the behavioral correlates of structure-function organization in a discrete population of ganglion-like cells.

Protecting retinal ganglion cells.

PubMed

Khatib, T Z; Martin, K R

2017-02-01

Retinal ganglion cell degeneration underlies several conditions which give rise to significant visual compromise, including glaucoma, hereditary optic neuropathies, ischaemic optic neuropathies, and demyelinating disease. In this review, we discuss the emerging strategies for neuroprotection specifically in the context of glaucoma, including pharmacological neuroprotection, mesenchymal stem cells, and gene therapy approaches. We highlight potential pitfalls that need to be considered when developing these strategies and outline future directions, including the prospects for clinical trials.

Clustering is a feature of the spiral ganglion in the basal turn.

PubMed

Gacek, Richard R

2012-01-01

To demonstrate the organization of the spiral ganglion in the mammalian species. Temporal bone (TB) specimens from man (n = 2), monkey (n = 2), lion (n = 2) and cat (n = 20) were stained, decalcified and dissected according to the Sudan black B method of Rasmussen. These TB specimens were examined under a Zeiss operating microscope and photographed with a Canon 100 camera interfaced with the microscope. Spiral ganglion cells occurred in clusters within Rosenthal's canal in all four species. The location of the clusters was marked by the interface between axon and dendritic bundles as well as groups of ganglion cells. In monkey and man the clusters were more separated than in lion and cat. These observations indicate that the spiral ganglion forms clusters of neurons within Rosenthal's canal at the basal cochlear turn in the mammals investigated here. The formation of clusters may be related to the principles of neurogenesis. Copyright © 2011 S. Karger AG, Basel.

Berberine exerts antioxidant effects via protection of spiral ganglion cells against cytomegalovirus-induced apoptosis.

PubMed

Zhuang, Wei; Li, Ting; Wang, Caiji; Shi, Xi; Li, Yalan; Zhang, Shili; Zhao, Zeqi; Dong, Hongyan; Qiao, Yuehua

2018-06-01

Cytomegalovirus (CMV) is the leading cause of sensorineural hearing loss (SNHL) in children because of its damage to the cochlea and spiral ganglion cells. Therefore, it has become a top priority to devise new methods to effectively protect spiral ganglion cells from damage. Berberine (BBR) has gained attention for its vast beneficial biological effects through immunomodulation, and its anti-inflammatory and anti-apoptosis properties. However, the effect of BBR on spiral ganglion cells and molecular mechanisms are still unclear. This study aims to investigate whether BBR has an anti-apoptosis effect in CMV-induced apoptosis in cultured spiral ganglion cells and explore the possible mechanism. In this study, TUNEL and MTT assays significantly demonstrated that low doses of BBR did not promote cell apoptosis and they also inhibited the CMV-induced cultured spiral ganglion cell apoptosis. Immunofluorescence and Western blot assays indicated that the anti-apoptosis effect of BBR was related to Nox3. Mitochondrial calcium and Western blot assays revealed that NMDAR1 mediated this anti-apoptosis effect. Our results demonstrated that BBR exerted an anti-apoptosis effect against CMV in cultured spiral ganglion cells, and the mechanism is related to NMDAR1/Nox3-mediated mitochondrial reactive oxygen species (ROS) generation. Copyright © 2018 Elsevier Inc. All rights reserved.

Retinal ganglion cell distribution and spatial resolving power in elasmobranchs.

PubMed

Lisney, Thomas J; Collin, Shaun P

2008-01-01

The total number, distribution and peak density of presumed retinal ganglion cells was assessed in 10 species of elasmobranch (nine species of shark and one species of batoid) using counts of Nissl-stained cells in retinal wholemounts. The species sampled include a number of active, predatory benthopelagic and pelagic sharks that are found in a variety of coastal and oceanic habitats and represent elasmobranch groups for which information of this nature is currently lacking. The topographic distribution of cells was heterogeneous in all species. Two benthic species, the shark Chiloscyllium punctatum and the batoid Taeniura lymma, have a dorsal or dorso-central horizontal streak of increased cell density, whereas the majority of the benthopelagic and pelagic sharks examined exhibit a more concentric pattern of increasing cell density, culminating in a central area centralis of higher cell density located close to the optic nerve head. The exception is the shark Alopias superciliosus, which possesses a ventral horizontal streak. Variation in retinal ganglion cell topography appears to be related to the visual demands of different habitats and lifestyles, as well as the positioning of the eyes in the head. The upper limits of spatial resolving power were calculated for all 10 species, using peak ganglion cell densities and estimates of focal length taken from cryo-sectioned eyes in combination with information from the literature. Spatial resolving power ranged from 2.02 to 10.56 cycles deg(-1), which is in accordance with previous studies. Species with a lower spatial resolving power tend to be benthic and/or coastal species that feed on benthic invertebrates and fishes. Active, benthopelagic and pelagic species from more oceanic habitats which feed on larger, more active prey, possess a higher resolving power. Additionally, ganglion cells in a juvenile of C. punctatum, were retrogradely-labeled from the optic nerve with biotinylated dextran amine (BDA). A comparison

[Met]- and [Leu]enkephalin-like immunoreactive cell bodies and nerve fibres in the coeliac ganglion of the cat.

PubMed

Julé, Y; Clerc, N; Niel, J P; Condamin, M

1986-06-01

The occurrence and distribution of methionine- and leucine-enkephalin-like immunoreactivity were investigated in the cat coeliac ganglion using either the indirect immunoperoxidase method or the peroxidase-antiperoxidase technique. Several antisera raised to methionine- and leucine-enkephalin were used. Their specificity was assessed by incubating sections of the coeliac ganglion with increasing dilutions of antisera and with antisera saturated with their respective antigen. The present study was performed both in untreated and in colchicine-treated cats. Immunoreactive methionine- and leucine-enkephalin-like cell bodies were only visualized in colchicine-treated cats. Two types of labeled cells were observed. The first type had a size similar to that of unlabeled principal ganglion cells. These labeled cells were numerous and scattered throughout the ganglion; they probably represented enkephalin-containing ganglion cells. The second type of immunoreactive cells were of a much smaller size. They were always gathered in small clusters of about 5-15 cells and were not numerous; they presumably represented enkephalin-containing small intensely fluorescent cells. Immunoreactive nerve fibres were mainly observed in untreated cats and accessorily in colchicine-treated cats. In untreated animals dense networks of methionine- and leucine-enkephalin-like immunoreactive fibres were found in the coeliac ganglion. These fibres had numerous varicosities which often closely surrounded unlabeled principal ganglion cells. In colchicine-treated cats some immunoreactive fibres surrounded labeled principal ganglion cell bodies. The present results establish for the first time the presence of enkephalin-like immunoreactive principal ganglion cells in a mammalian sympathetic prevertebral ganglion. The presence of enkephalin-containing principal ganglion cells, small intensely fluorescent cells and nerve terminals, supports an important role of enkephalins in the integrative synaptic

Protecting retinal ganglion cells

PubMed Central

Khatib, T Z; Martin, K R

2017-01-01

Retinal ganglion cell degeneration underlies several conditions which give rise to significant visual compromise, including glaucoma, hereditary optic neuropathies, ischaemic optic neuropathies, and demyelinating disease. In this review, we discuss the emerging strategies for neuroprotection specifically in the context of glaucoma, including pharmacological neuroprotection, mesenchymal stem cells, and gene therapy approaches. We highlight potential pitfalls that need to be considered when developing these strategies and outline future directions, including the prospects for clinical trials. PMID:28085136

Features and functions of nonlinear spatial integration by retinal ganglion cells.

PubMed

Gollisch, Tim

2013-11-01

Ganglion cells in the vertebrate retina integrate visual information over their receptive fields. They do so by pooling presynaptic excitatory inputs from typically many bipolar cells, which themselves collect inputs from several photoreceptors. In addition, inhibitory interactions mediated by horizontal cells and amacrine cells modulate the structure of the receptive field. In many models, this spatial integration is assumed to occur in a linear fashion. Yet, it has long been known that spatial integration by retinal ganglion cells also incurs nonlinear phenomena. Moreover, several recent examples have shown that nonlinear spatial integration is tightly connected to specific visual functions performed by different types of retinal ganglion cells. This work discusses these advances in understanding the role of nonlinear spatial integration and reviews recent efforts to quantitatively study the nature and mechanisms underlying spatial nonlinearities. These new insights point towards a critical role of nonlinearities within ganglion cell receptive fields for capturing responses of the cells to natural and behaviorally relevant visual stimuli. In the long run, nonlinear phenomena of spatial integration may also prove important for implementing the actual neural code of retinal neurons when designing visual prostheses for the eye. Copyright © 2012 Elsevier Ltd. All rights reserved.

Cochlear implants and ex vivo BDNF gene therapy protect spiral ganglion neurons.

PubMed

Rejali, Darius; Lee, Valerie A; Abrashkin, Karen A; Humayun, Nousheen; Swiderski, Donald L; Raphael, Yehoash

2007-06-01

Spiral ganglion neurons often degenerate in the deaf ear, compromising the function of cochlear implants. Cochlear implant function can be improved by good preservation of the spiral ganglion neurons, which are the target of electrical stimulation by the implant. Brain derived neurotrophic factor (BDNF) has previously been shown to enhance spiral ganglion survival in experimentally deafened ears. Providing enhanced levels of BDNF in human ears may be accomplished by one of several different methods. The goal of these experiments was to test a modified design of the cochlear implant electrode that includes a coating of fibroblast cells transduced by a viral vector with a BDNF gene insert. To accomplish this type of ex vivo gene transfer, we transduced guinea pig fibroblasts with an adenovirus with a BDNF gene cassette insert, and determined that these cells secreted BDNF. We then attached BDNF-secreting cells to the cochlear implant electrode via an agarose gel, and implanted the electrode in the scala tympani. We determined that the BDNF expressing electrodes were able to preserve significantly more spiral ganglion neurons in the basal turns of the cochlea after 48 days of implantation when compared to control electrodes. This protective effect decreased in the higher cochlear turns. The data demonstrate the feasibility of combining cochlear implant therapy with ex vivo gene transfer for enhancing spiral ganglion neuron survival.

Insulin-like growth factor-1 prevents dorsal root ganglion neuronal tyrosine kinase receptor expression alterations induced by dideoxycytidine in vitro.

PubMed

Liu, Huaxiang; Lu, Jing; He, Yong; Yuan, Bin; Li, Yizhao; Li, Xingfu

2014-03-01

Dideoxycytidine (zalcitabine, ddC) produces neurotoxic effects. It is particularly important to understand the toxic effects of ddC on different subpopulations of dorsal root ganglion (DRG) neurons which express distinct tyrosine kinase receptor (Trk) and to find therapeutic factors for prevention and therapy for ddC-induced peripheral sensory neuropathy. Insulin-like growth factor-1 (IGF-1) has been shown to have neurotrophic effects on DRG sensory neurons. However, little is known about the effects of ddC on distinct Trk (TrkA, TrkB, and TrkC) expression in DRG neurons and the neuroprotective effects of IGF-1 on ddC-induced neurotoxicity. Here, we have tested the extent to which the expression of TrkA, TrkB, and TrkC receptors in primary cultured DRG neurons is affected by ddC in the presence or absence of IGF-1. In this experiment, we found that exposure of 5, 25, and 50 μmol/L ddC caused a dose-dependent decrease of the mRNA, protein, and the proportion of TrkA-, TrkB-, and TrkC-expressing neurons. IGF-1 (20 nmol/L) could partially reverse the decrease of TrkA and TrkB, but not TrkC, expression with ddC exposure. The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (10 μmol/L) blocked the effects of IGF-1. These results suggested that the subpopulations of DRG neurons which express distinct TrkA, TrkB, and TrkC receptors were affected by ddC exposure. IGF-1 might relieve the ddC-induced toxicity of TrkA- and TrkB-, but not TrkC-expressing DRG neurons. These data offer new clues for a better understanding of the association of ddC with distinct Trk receptor expression and provide new evidence of the potential therapeutic role of IGF-1 on ddC-induced neurotoxicity.

Intrinsically photosensitive retinal ganglion cells.

PubMed

Do, Michael Tri Hoang; Yau, King-Wai

2010-10-01

Life on earth is subject to alternating cycles of day and night imposed by the rotation of the earth. Consequently, living things have evolved photodetective systems to synchronize their physiology and behavior with the external light-dark cycle. This form of photodetection is unlike the familiar "image vision," in that the basic information is light or darkness over time, independent of spatial patterns. "Nonimage" vision is probably far more ancient than image vision and is widespread in living species. For mammals, it has long been assumed that the photoreceptors for nonimage vision are also the textbook rods and cones. However, recent years have witnessed the discovery of a small population of retinal ganglion cells in the mammalian eye that express a unique visual pigment called melanopsin. These ganglion cells are intrinsically photosensitive and drive a variety of nonimage visual functions. In addition to being photoreceptors themselves, they also constitute the major conduit for rod and cone signals to the brain for nonimage visual functions such as circadian photoentrainment and the pupillary light reflex. Here we review what is known about these novel mammalian photoreceptors.

A patient-mount navigated intervention system for spinal diseases and its clinical trial on percutaneous pulsed radiofrequency stimulation of dorsal root ganglion.

PubMed

Yang, Chi-Lin; Yang, Been-Der; Lin, Mu-Lien; Wang, Yao-Hung; Wang, Jaw-Lin

2010-10-01

Development of a patient-mount navigated intervention (PaMNI) system for spinal diseases. An in vivo clinical human trial was conducted to validate this system. To verify the feasibility of the PaMNI system with the clinical trial on percutaneous pulsed radiofrequency stimulation of dorsal root ganglion (PRF-DRG). Two major image guiding techniques, i.e., computed tomography (CT)-guided and fluoro-guided, were used for spinal intervention. The CT-guided technique provides high spatial resolution, and is claimed to be more accurate than the fluoro-guided technique. Nevertheless, the CT-guided intervention usually reaches higher radiograph exposure than the fluoro-guided counterpart. Some navigated intervention systems were developed to reduce the radiation of CT-guided intervention. Nevertheless, these systems were not popularly used due to the longer operation time, a new protocol for surgeons, and the availability of such a system. The PaMNI system includes 3 components, i.e., a patient-mount miniature tracking unit, an auto-registered reference frame unit, and a user-friendly image processing unit. The PRF-DRG treatment was conducted to find the clinical feasibility of this system. The in vivo clinical trial showed that the accuracy, visual analog scale evaluation after surgery, and radiograph exposure of the PaMNI-guided technique are comparable to the one of conventional fluoro-guided technique, while the operation time is increased by 5 minutes. Combining the virtues of fluoroscopy and CT-guided techniques, our navigation system is operated like a virtual fluoroscopy with augmented CT images. This system elevates the performance of CT-guided intervention and reduces surgeons' radiation exposure risk to a minimum, while keeping low radiation dose to patients like its fluoro-guided counterpart. The clinical trial of PRF-DRG treatment showed the clinical feasibility and efficacy of this system.

Insulin-like growth factor-1 attenuates apoptosis and protects neurochemical phenotypes of dorsal root ganglion neurons with paclitaxel-induced neurotoxicity in vitro.

PubMed

Chen, Cheng; Bai, Xue; Bi, Yanwen; Liu, Guixiang; Li, Hao; Liu, Zhen; Liu, Huaxiang

2017-02-01

Paclitaxel (PT)-induced neurotoxicity is a significant problem associated with successful treatment of cancers. Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor and plays an important role in promoting axonal growth from dorsal root ganglion (DRG) neurons. Whether IGF-1 has protective effects on neurite growth, cell viability, neuronal apoptosis and neuronal phenotypes in DRG neurons with PT-induced neurotoxicity is still unclear. In this study, primary cultured rat DRG neurons were used to assess the effects of IGF-1 on DRG neurons with PT-induced neurotoxicity. The results showed that PT exposure caused neurite retraction in a dose-dependent manner. PT exposure caused a decrease of cell viability and an increase in the ratio of apoptotic cells which could be reversed by IGF-1. The percentage of calcitonin gene-related peptide immunoreactive (CGRP-IR) neurons and neurofilament (NF)-200-IR neurons, mRNA, and protein levels of CGRP and NF-200 decreased significantly after treatment with PT. IGF-1 administration had protective effects on CGRP-IR neurons, but not on NF-200-IR neurons. Either extracellular signal-regulated protein kinase (ERK1/2) inhibitor PD98059 or phosphatidylinositol 3-kinase (PI3 K) inhibitor LY294002 blocked the effect of IGF-1. The results imply that IGF-1 may attenuate apoptosis to improve neuronal cell viability and promote neurite growth of DRG neurons with PT-induced neurotoxicity. Moreover, these results support an important neuroprotective role of exogenous IGF-1 on distinct subpopulations of DRG neurons which is responsible for skin sensation. The effects of IGF-1 might be through ERK1/2 or PI3 K/Akt signaling pathways. These findings provide experimental evidence for IGF-1 administration to alleviate neurotoxicity of distinct subpopulations of DRG neurons induced by PT.

Differential contribution of Kv4-containing channels to A-type, voltage-gated potassium currents in somatic and visceral dorsal root ganglion neurons.

PubMed

Yunoki, Takakazu; Takimoto, Koichi; Kita, Kaori; Funahashi, Yasuhito; Takahashi, Ryosuke; Matsuyoshi, Hiroko; Naito, Seiji; Yoshimura, Naoki

2014-11-15

Little is known about electrophysiological differences of A-type transient K(+) (KA) currents in nociceptive afferent neurons that innervate somatic and visceral tissues. Staining with isolectin B4 (IB4)-FITC classifies L6-S1 dorsal root ganglion (DRG) neurons into three populations with distinct staining intensities: negative to weak, moderate, and intense fluorescence signals. All IB4 intensely stained cells are negative for a fluorescent dye, Fast Blue (FB), injected into the bladder wall, whereas a fraction of somatic neurons labeled by FB, injected to the external urethral dermis, is intensely stained with IB4. In whole-cell, patch-clamp recordings, phrixotoxin 2 (PaTx2), a voltage-gated K(+) (Kv)4 channel blocker, exhibits voltage-independent inhibition of the KA current in IB4 intensely stained cells but not the one in bladder-innervating cells. The toxin also shows voltage-independent inhibition of heterologously expressed Kv4.1 current, whereas its inhibition of Kv4.2 and Kv4.3 currents is voltage dependent. The swapping of four amino acids at the carboxyl portion of the S3 region between Kv4.1 and Kv4.2 transfers this characteristic. RT-PCRs detected Kv4.1 and the long isoform of Kv4.3 mRNAs without significant Kv4.2 mRNA in L6-S1 DRGs. Kv4.1 and Kv4.3 mRNA levels were higher in laser-captured, IB4-stained neurons than in bladder afferent neurons. These results indicate that PaTx2 acts differently on channels in the Kv4 family and that Kv4.1 and possibly Kv4.3 subunits functionally participate in the formation of KA channels in a subpopulation of somatic C-fiber neurons but not in visceral C-fiber neurons innervating the bladder. Copyright © 2014 the American Physiological Society.

Differential contribution of Kv4-containing channels to A-type, voltage-gated potassium currents in somatic and visceral dorsal root ganglion neurons

PubMed Central

Yunoki, Takakazu; Takimoto, Koichi; Kita, Kaori; Funahashi, Yasuhito; Takahashi, Ryosuke; Matsuyoshi, Hiroko; Naito, Seiji

2014-01-01

Little is known about electrophysiological differences of A-type transient K+ (KA) currents in nociceptive afferent neurons that innervate somatic and visceral tissues. Staining with isolectin B4 (IB4)-FITC classifies L6-S1 dorsal root ganglion (DRG) neurons into three populations with distinct staining intensities: negative to weak, moderate, and intense fluorescence signals. All IB4 intensely stained cells are negative for a fluorescent dye, Fast Blue (FB), injected into the bladder wall, whereas a fraction of somatic neurons labeled by FB, injected to the external urethral dermis, is intensely stained with IB4. In whole-cell, patch-clamp recordings, phrixotoxin 2 (PaTx2), a voltage-gated K+ (Kv)4 channel blocker, exhibits voltage-independent inhibition of the KA current in IB4 intensely stained cells but not the one in bladder-innervating cells. The toxin also shows voltage-independent inhibition of heterologously expressed Kv4.1 current, whereas its inhibition of Kv4.2 and Kv4.3 currents is voltage dependent. The swapping of four amino acids at the carboxyl portion of the S3 region between Kv4.1 and Kv4.2 transfers this characteristic. RT-PCRs detected Kv4.1 and the long isoform of Kv4.3 mRNAs without significant Kv4.2 mRNA in L6-S1 DRGs. Kv4.1 and Kv4.3 mRNA levels were higher in laser-captured, IB4-stained neurons than in bladder afferent neurons. These results indicate that PaTx2 acts differently on channels in the Kv4 family and that Kv4.1 and possibly Kv4.3 subunits functionally participate in the formation of KA channels in a subpopulation of somatic C-fiber neurons but not in visceral C-fiber neurons innervating the bladder. PMID:25143545

TRPC1 is required for survival and proliferation of cochlear spiral ganglion stem/progenitor cells.

PubMed

Chen, Hsin-Chien; Wang, Chih-Hung; Shih, Cheng-Ping; Chueh, Sheau-Huei; Liu, Shu-Fan; Chen, Hang-Kang; Lin, Yi-Chun

2015-12-01

The present studies were designed to test the hypothesis that canonical transient receptor potential channel 1 (TRPC1) is required for the proliferation of cochlear spiral ganglion stem/progenitor cells (SPCs). TRPC1 were detected and evaluated in postnatal day 1 CBA/CaJ mice pups derived-cochlear spiral ganglion SPCs by reverse transcription-polymerase chain reaction, Western blot, immunocytochemistry, and calcium imaging. The cell viability and proliferation of the spiral ganglion SPCs following si-RNA mediated knockdown of TRPC1 or addition of TRPC channel blocker SKF9635 were compared to controls. In spiral ganglion SPCs, TRPC1 was found to be the most abundantly expressed TRPC subunit and shown to contribute to store-operated calcium entry. Silencing of TRPC1 or addition of TRPC channel blockers significantly decreased the rate of cell proliferation. The results suggest that TRPC1 might serve as an essential molecule in regulating the proliferation of spiral ganglion SPCs. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Regenerative effects of human embryonic stem cell-derived neural crest cells for treatment of peripheral nerve injury.

PubMed

Jones, Iwan; Novikova, Liudmila N; Novikov, Lev N; Renardy, Monika; Ullrich, Andreas; Wiberg, Mikael; Carlsson, Leif; Kingham, Paul J

2018-04-01

Surgical intervention is the current gold standard treatment following peripheral nerve injury. However, this approach has limitations, and full recovery of both motor and sensory modalities often remains incomplete. The development of artificial nerve grafts that either complement or replace current surgical procedures is therefore of paramount importance. An essential component of artificial grafts is biodegradable conduits and transplanted cells that provide trophic support during the regenerative process. Neural crest cells are promising support cell candidates because they are the parent population to many peripheral nervous system lineages. In this study, neural crest cells were differentiated from human embryonic stem cells. The differentiated cells exhibited typical stellate morphology and protein expression signatures that were comparable with native neural crest. Conditioned media harvested from the differentiated cells contained a range of biologically active trophic factors and was able to stimulate in vitro neurite outgrowth. Differentiated neural crest cells were seeded into a biodegradable nerve conduit, and their regeneration potential was assessed in a rat sciatic nerve injury model. A robust regeneration front was observed across the entire width of the conduit seeded with the differentiated neural crest cells. Moreover, the up-regulation of several regeneration-related genes was observed within the dorsal root ganglion and spinal cord segments harvested from transplanted animals. Our results demonstrate that the differentiated neural crest cells are biologically active and provide trophic support to stimulate peripheral nerve regeneration. Differentiated neural crest cells are therefore promising supporting cell candidates to aid in peripheral nerve repair. © 2018 The Authors. Journal of Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd.

A decay of gap junctions associated with ganglion cell differentiation during retinal regeneration of the adult newt.

PubMed

Oi, Hanako; Chiba, Chikafumi; Saito, Takehiko

2003-12-01

Changes in the gap junctional coupling and maturation of voltage-activated Na(+) currents during regeneration of newt retinas were examined by whole-cell patch-clamping in slice preparations. Progenitor cells in regenerating retinas did not exhibit Na(+) currents but showed prominent electrical and tracer couplings. Cells identified by LY-fills were typically slender. Na(+) currents were detected in premature ganglion cells with round somata in the 'intermediate-II' regenerating retina. No electrical and tracer couplings were observed between these cells. Mature ganglion cells did not exhibit electrical coupling, but showed tracer coupling. On average, the maximum Na(+) current amplitude recorded from premature ganglion cells was roughly 2.5-fold smaller than that of mature ganglion cells. In addition, the activation threshold of the Na(+) current was nearly 11 mV more positive than that of mature cells. We provide morphological and physiological evidence showing that loss of gap junctions between progenitor cells is associated with ganglion cell differentiation during retinal regeneration and that new gap junctions are recreated between mature ganglion cells. Also we provide evidence suggesting that the loss of gap junctions correlates with the appearance of voltage-activated Na(+) currents in ganglion cells.

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor.

PubMed

Mavlyutov, Timur A; Nickells, Robert W; Guo, Lian-Wang

2011-04-26

The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1(-/-)) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1(-/-) mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1(-/-), demonstrating a significant difference between the wild-type and the Sigmar1(-/-) in crush-induced ganglion cell loss. Our data indicated faster retinal ganglion cell death in Sigmar1(-/-) than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma.

Advanced Oxidative Protein Products Cause Pain Hypersensitivity in Rats by Inducing Dorsal Root Ganglion Neurons Apoptosis via NADPH Oxidase 4/c-Jun N-terminal Kinase Pathways.

PubMed

Ding, Ruoting; Sun, Baihui; Liu, Zhongyuan; Yao, Xinqiang; Wang, Haiming; Shen, Xing; Jiang, Hui; Chen, Jianting

2017-01-01

Pain hypersensitivity is the most common category of chronic pain and is difficult to cure. Oxidative stress and certain cells apoptosis, such as dorsal root ganglion (DRG) neurons, play an essential role in the induction and development of pain hypersensitivity. The focus of this study is at a more specific molecular level. We investigated the role of advanced oxidative protein products (AOPPs) in inducing hypersensitivity and the cellular mechanism underlying the proapoptotic effect of AOPPs. Normal rats were injected by AOPPs-Rat serum albumin (AOPPs-RSA) to cause pain hypersensitivity. Primary cultured DRG neurons were treated with increasing concentrations of AOPPs-RSA or for increasing time durations. The MTT, flow cytometry and western blot analyses were performed in the DRG neurons. A loss of mitochondrial membrane potential (MMP) and an increase in intracellular reactive oxygen species (ROS) were observed. We found that AOPPs triggered DRG neurons apoptosis and MMP loss. After AOPPs treatment, intracellular ROS generation increased in a time- and dose-dependent manner, whereas, N -acetyl-L-cysteine (NAC), a specific ROS scavenger could inhibit the ROS generation. Proapoptotic proteins, such as Bax, caspase 9/caspase 3, and PARP-1 were activated, whereas anti-apoptotic Bcl-2 protein was down-regulated. AOPPs also increased Nox4 and JNK expression. Taken together, these findings suggest that AOPPs cause pain hypersensitivity in rats, and extracellular AOPPs accumulation triggered Nox4-dependent ROS production, which activated JNK, and induced DRG neurons apoptosis by activating caspase 3 and PARP-1.

Threshold setting by the surround of cat retinal ganglion cells.

PubMed

Barlow, H B; Levick, W R

1976-08-01

1. The slope of curves relating the log increment threshold to log background luminance in cat retinal ganglion cells is affected by the area and duration of the test stimulus, as it is in human pyschophysical experiments. 2. Using large area, long duration stimuli the slopes average 0-82 and approach close to 1 (Weber's Law) in the steepest cases. Small stimuli gave an average of 0-53 for on-centre units using brief stimuli, and 0-56 for off-centre units, using long stimuli. Slopes under 0-5 (square root law) were not found over an extended range of luminances. 3. On individual units the slope was generally greater for larger and longer test stimulus, but no unit showed the full extent of change from slope of 0-5 to slope of 1. 4. The above differences hold for objective measures of quantum/spike ratio, as well as for thresholds either judged by ear or assessed by calculation. 5. The steeper slope of the curves for large area, long duration test stimuli compared with small, long duration stimuli, is associated with the increased effectiveness of antagonism from the surround at high backgrounds. This change may be less pronounced in off-centre units, one of which (probably transient Y-type) showed no difference of slope, and gave parallel area-threshold curves at widely separated background luminances, confirming the importance of differential surround effectiveness in changing the slope of the curves. 6. In on-centre units, the increased relative effectiveness of the surround is associated with the part of the raised background light that falls on the receptive field centre. 7. It is suggested that the variable surround functions as a zero-offset control that sets the threshold excitation required for generating impulses, and that this is separate from gain-setting adaptive mechanisms. This may be how ganglion cells maintain high incremental sensitivity in spite of a strong maintained excitatory drive that would otherwise cause compressive response non-linearities.

Angioarchitecture of the coeliac sympathetic ganglion complex in the common tree shrew (Tupaia glis)

PubMed Central

PROMWIKORN, WARAPORN; THONGPILA, SAKPORN; PRADIDARCHEEP, WISUIT; MINGSAKUL, THAWORN; CHUNHABUNDIT, PANJIT; SOMANA, REON

1998-01-01

The angioarchitecture of the coeliac sympathetic ganglion complex (CGC) of the common tree shrew (Tupaia glis) was studied by the vascular corrosion cast technique in conjunction with scanning electron microscopy. The CGC of the tree shrew was found to be a highly vascularised organ. It normally received arterial blood supply from branches of the inferior phrenic, superior suprarenal and inferior suprarenal arteries and of the abdominal aorta. In some animals, its blood supply was also derived from branches of the middle suprarenal arteries, coeliac artery, superior mesenteric artery and lumbar arteries. These arteries penetrated the ganglion at variable points and in slightly different patterns. They gave off peripheral branches to form a subcapsular capillary plexus while their main trunks traversed deeply into the inner part before branching into the densely packed intraganglionic capillary networks. The capillaries merged to form venules before draining into collecting veins at the peripheral region of the ganglion complex. Finally, the veins coursed to the dorsal aspect of the ganglion to drain into the renal and inferior phrenic veins and the inferior vena cava. The capillaries on the coeliac ganglion complex do not possess fenestrations. PMID:9877296

Retinal ganglion cell projections to the hamster suprachiasmatic nucleus, intergeniculate leaflet, and visual midbrain: bifurcation and melanopsin immunoreactivity

NASA Technical Reports Server (NTRS)

Morin, Lawrence P.; Blanchard, Jane H.; Provencio, Ignacio

2003-01-01

The circadian clock in the suprachiasmatic nucleus (SCN) receives direct retinal input via the retinohypothalamic tract (RHT), and the retinal ganglion cells contributing to this projection may be specialized with respect to direct regulation of the circadian clock. However, some ganglion cells forming the RHT bifurcate, sending axon collaterals to the intergeniculate leaflet (IGL) through which light has secondary access to the circadian clock. The present studies provide a more extensive examination of ganglion cell bifurcation and evaluate whether ganglion cells projecting to several subcortical visual nuclei contain melanopsin, a putative ganglion cell photopigment. The results showed that retinal ganglion cells projecting to the SCN send collaterals to the IGL, olivary pretectal nucleus, and superior colliculus, among other places. Melanopsin-immunoreactive (IR) ganglion cells are present in the hamster retina, and some of these cells project to the SCN, IGL, olivary pretectal nucleus, or superior colliculus. Triple-label analysis showed that melanopsin-IR cells bifurcate and project bilaterally to each SCN, but not to the other visual nuclei evaluated. The melanopsin-IR cells have photoreceptive characteristics optimal for circadian rhythm regulation. However, the presence of moderately widespread bifurcation among ganglion cells projecting to the SCN, and projection by melanopsin-IR cells to locations distinct from the SCN and without known rhythm function, suggest that this ganglion cell type is generalized, rather than specialized, with respect to the conveyance of photic information to the brain. Copyright 2003 Wiley-Liss, Inc.

Effects of ischemic phrenic nerve root ganglion injury on respiratory disturbances in subarachnoid hemorrhage: an experimental study.

PubMed

Ulvi, Hızır; Demir, Recep; Aygül, Recep; Kotan, Dilcan; Calik, Muhammet; Aydin, Mehmet Dumlu

2013-12-30

Phrenic nerves have important roles on the management of respiration rhythm. Diaphragm paralysis is possible in phrenic nerve roots ischemia in subarachnoid hemorrhage (SAH). We examined whether there is a relationship between phrenic nerve root ischemia and respiratory disturbances in SAH. This study was conducted on 5 healthy control and 14 rabbits with experimentally induced SAH by injecting autologous blood into their cisterna magna. Animals were followed up via monitors for detecting the heart and respiration rhythms for 20 days and then decapitaed by humanely. Normal and degenerated neuron densities of phrenic nerve root at the level of C4 dorsal root ganglia (C4DRG) were estimated by Stereological methods. Between the mean numerical density of degenerated neurons of C4DRG and respiratory rate/minute of groups were compared statistically. Phrenic nerve roots, artery and diaphragm muscles degeneration was detected in respiratory arrest developed animals. The mean neuronal density of C4DRG was 13272 ±1201/mm3 with a mean respiration rate of 23 ±4/min in the control group. The mean degenerated neuron density was 2.240 ±450/mm(3) and respiration rhythm was 31 ±6/min in survivors. But, the mean degenerated neuron density was 5850 ±650/mm(3) and mean respiration rhythm was 34 ±7/min in respiratory arrest developed animals (n = 7). A linear relationship was noticed between the degenerated neuron density of C4DRG and respiraton rate (r = -0.758; p < 0.001). Phrenic nerve root ischemia may be an important factor in respiration rhythms deteriorations in SAH which has not been mentioned in the literature.

Thresholds for activation of rabbit retinal ganglion cells with an ultrafine, extracellular microelectrode.

PubMed

Jensen, Ralph J; Rizzo, Joseph F; Ziv, Ofer R; Grumet, Andrew; Wyatt, John

2003-08-01

To determine electrical thresholds required for extracellular activation of retinal ganglion cells as part of a project to develop an epiretinal prosthesis. Retinal ganglion cells were recorded extracellularly in retinas isolated from adult New Zealand White rabbits. Electrical current pulses of 100- micro s duration were delivered to the inner surface of the retina from a 5- micro m long electrode. In about half of the cells, the point of lowest threshold was found by searching with anodal current pulses; in the other cells, cathodal current pulses were used. Threshold measurements were obtained near the cell bodies of 20 ganglion cells and near the axons of 19 ganglion cells. Both cathodal and anodal stimuli evoked a neural response in the ganglion cells that consisted of a single action potential of near-constant latency that persisted when retinal synaptic transmission was blocked with cadmium chloride. For cell bodies, but not axons, thresholds for both cathodal and anodal stimulation were dependent on the search method used to find the point of lowest threshold. With search and stimulation of matching polarity, cathodal stimuli evoked a ganglion cell response at lower currents (approximately one seventh to one tenth axonal threshold) than did anodal stimuli for both cell bodies and axons. With cathodal search and stimulation, cell body median thresholds were somewhat lower (approximately one half) than the axonal median thresholds. With anodal search and stimulation, cell body median thresholds were approximately the same as axonal median thresholds. The results suggest that cathodal stimulation should produce lower thresholds, more localized stimulation, and somewhat better selectivity for cell bodies over axons than would anodal stimulation.

Iridovirus infection of cell cultures from the Diaprepes root weevil, Diaprepes abbreviatus

PubMed Central

Hunter, W. B.; Lapointe, S. L.

2003-01-01

We here report the development and viral infection of a Diaprepes root weevil cell culture. Embryonic tissues of the root weevil were used to establish cell cultures for use in screening viral pathogens as potential biological control agents. Tissues were seeded into a prepared solution of insect medium and kept at a temperature of 24°C. The cell culture had primarily fibroblast-like morphology with some epithelial monolayers. Root weevil cells were successfully infected in vitro with a known insect virus, Invertebrate Iridescent Virus 6. Potential uses of insect cell cultures and insect viruses are discussed. Abbreviation: IIV-6 Invertebrate Iridescent Virus 6 PMID:15841252

Blood-nerve barrier: distribution of anionic sites on the endothelial plasma membrane and basal lamina of dorsal root ganglia.

PubMed

Bush, M S; Reid, A R; Allt, G

1991-09-01

Previous investigations of the blood-nerve barrier have correlated the greater permeability of ganglionic endoneurial vessels, compared to those of nerve trunks, with the presence of fenestrations and open intercellular junctions. Recent studies have demonstrated reduced endothelial cell surface charge in blood vessels showing greater permeability. To determine the distribution of anionic sites on the plasma membranes and basal laminae of endothelial cells in dorsal root ganglia, cationic colloidal gold and cationic ferritin were used. Electron microscopy revealed the existence of endothelial microdomains with differing labelling densities. Labelling indicated that caveolar and fenestral diaphragms and basal laminae are highly anionic at physiological pH, luminal plasma membranes and endothelial processes are moderately charged and abluminal plasma membranes are weakly anionic. Tracers did not occur in caveolae or cytoplasmic vesicles. In vitro tracer experiments at pH values of 7.3, 5.0, 3.5 and 2.0 indicated that the anionic charge on the various endothelial domains was contributed by chemical groups with differing pKa values. In summary, the labelling of ganglionic and sciatic nerve vessels was similar except for the heavy labelling of diaphragms in a minority of endoneurial vessels in ganglia. This difference is likely to account in part for the greater permeability of ganglionic endoneurial vessels. The results are discussed with regard to the blood-nerve and -brain barriers and vascular permeability in other tissues and a comparison made between the ultrastructure and anionic microdomains of epi-, peri- and endoneurial vessels of dorsal root ganglia and sciatic nerves.

Retinal vascular injuries and intravitreal human embryonic stem cell-derived haemangioblasts.

PubMed

Wang, Jin-Da; An, Ying; Zhang, Jing-Shang; Wan, Xiu-Hua; Zhang, Wei; Lanza, Robert; Lu, Shi-Jiang; Jonas, Jost B; Xu, Liang

2017-09-01

To investigate whether intravitreally applied haemangioblasts (HB) derived from human embryonic stem cells (hESCs) are helpful for the repair of vascular damage caused in animals by an oxygen-induced retinopathy (OIR), by an induced diabetic retinopathy (DR) or by an induced retinal ischaemia with subsequent reperfusion. Human embryonic stem cell-derived HBs were transplanted intravitreally into C57BL/6J mice (OIR model), into male Wistar rats with an induced DR and into male Wistar rats undergoing induced retinal ischaemia with subsequent reperfusion. Control groups of animals received an intravitreal injection of endothelial cells (ECs) or phosphate-buffered saline (PBS). We examined the vasculature integrity in the mice with OIR, the blood-retina barrier in the rats with induced DR, and retinal thickness and retinal ganglion cell density in retina flat mounts of the rats with the retinal ischaemic-reperfusion retinopathy. In the OIR model, the study group versus control groups showed a significantly (p < 0.001) smaller retinal avascular area [5.1 ± 2.7%;n = 18 animals versus 12.2 ± 2.8% (PBS group; n = 10 animals) and versus 11.8 ± 3.7% (EC group; n = 8 animals)] and less retinal neovascularization [6.3 ± 2.5%;n = 18 versus 15.2 ± 6.3% (n = 10; PBS group) and versus 15.8 ± 3.3% (n = 8; EC group)]. On retinal flat mounts, hESC-HBs were integrated into damaged retinal vessels and stained positive for PECAM (CD31) as EC marker. In the DR model, the study group versus the EC control group showed a significantly (p = 0.001) better blood-retina barrier function as measured at 2 days after the intravitreal injections [study group: 20.2 ± 12.8 μl/(g × hr); n = 6; versus EC control group: 52.9 ± 9.9 μl/(g × hr; n = 6)]. In the retinal ischaemia-reperfusion model, the groups did not differ significantly in retinal thickness and retinal ganglion cell density at 2, 5 and 7 days after baseline. By integrating into

Muscarinic Acetylcholine Receptor Localization and Activation Effects on Ganglion Response Properties

PubMed Central

Renna, Jordan M.; Amthor, Franklin R.; Keyser, Kent T.

2010-01-01

Purpose. The activation and blockade of muscarinic acetylcholine receptors (mAChRs) affects retinal ganglion cell light responses and firing rates. This study was undertaken to identify the full complement of mAChRs expressed in the rabbit retina and to assess mAChR distribution and the functional effects of mAChR activation and blockade on retinal response properties. Methods. RT-PCR, Western blot analysis, and immunohistochemistry were used to identify the complement and distribution of mAChRs in the rabbit retina. Extracellular electrophysiology was used to determine the effects of the activation or blockade of mAChRs on ganglion cell response properties. Results. RT-PCR of whole neural retina resulted in the amplification of mRNA transcripts for the m1 to m5 mAChR subtypes. Western blot and immunohistochemical analyses confirmed that all five mAChR subtypes were expressed by subpopulations of bipolar, amacrine, and ganglion cells in the rabbit retina, including subsets of cells in cholinergic and glycinergic circuits. Nonspecific muscarinic activation and blockade resulted in the class-specific modulation of maintained ganglion cell firing rates and light responses. Conclusions. The expression of mAChR subtypes on subsets of bipolar, amacrine, and ganglion cells provides a substrate for both enhancement and suppression of retinal responses via activation by cholinergic agents. Thus, the muscarinic cholinergic system in the retina may contribute to the modulation of complex stimuli. Understanding the distribution and function of mAChRs in the retina has the potential to provide important insights into the visual changes that are caused by decreased ACh in the retinas of Alzheimer's patients and the potential visual effects of anticholinergic treatments for ocular diseases. PMID:20042645

Broad Thorny Ganglion Cells: A Candidate for Visual Pursuit Error Signaling in the Primate Retina

PubMed Central

Manookin, Michael B.; Neitz, Jay; Rieke, Fred

2015-01-01

Functional analyses exist only for a few of the morphologically described primate ganglion cell types, and their correlates in other mammalian species remain elusive. Here, we recorded light responses of broad thorny cells in the whole-mounted macaque retina. They showed ON-OFF-center light responses that were strongly suppressed by stimulation of the receptive field surround. Spike responses were delayed compared with parasol ganglion cells and other ON-OFF cells, including recursive bistratified ganglion cells and A1 amacrine cells. The receptive field structure was shaped by direct excitatory synaptic input and strong presynaptic and postsynaptic inhibition in both ON and OFF pathways. The cells responded strongly to dark or bright stimuli moving either in or out of the receptive field, independent of the direction of motion. However, they did not show a maintained spike response either to a uniform background or to a drifting plaid pattern. These properties could be ideally suited for guiding movements involved in visual pursuit. The functional characteristics reported here permit the first direct cross-species comparison of putative homologous ganglion cell types. Based on morphological similarities, broad thorny ganglion cells have been proposed to be homologs of rabbit local edge detector ganglion cells, but we now show that the two cells have quite distinct physiological properties. Thus, our data argue against broad thorny cells as the homologs of local edge detector cells. PMID:25834063

Paracoccygeal corkscrew approach to ganglion impar injections for tailbone pain.

PubMed

Foye, Patrick M; Patel, Shounuck I

2009-01-01

A new technique for performing nerve blocks of the ganglion impar (ganglion Walther) is presented. These injections have been reported to relieve coccydynia (tailbone pain), as well as other malignant and nonmalignant pelvic pain syndromes. A variety of techniques have been previously described for blocking this sympathetic nerve ganglion, which is located in the retrorectal space just anterior to the upper coccygeal segments. Prior techniques have included approaches through the anococcygeal ligament, through the sacrococcygeal joint, and through intracoccygeal joint spaces. This article presents a new, paracoccygeal approach whereby the needle is inserted alongside the coccyx and the needle is guided through three discrete steps with a rotating or corkscrew trajectory. Compared with some of the previously published techniques, this paracoccygeal corkscrew approach has multiple potential benefits, including ease of fluoroscopic guidance using the lateral view, ability to easily use a stylet for the spinal needle, and use of a shorter, thinner needle. While no single technique works best for all patients and each technique has potential advantages and disadvantages, this new technique adds to the available options.

The different roles of opioid receptors in the inhibitory effects induced by sacral dorsal root ganglion stimulation on nociceptive and nonnociceptive conditions in cats.

PubMed

Wang, Zhaoxia; Liao, Limin; Deng, Han; Li, Xing; Chen, Guoqing; Liao, Xiwen

2018-06-04

To examine the roles of opioid receptors in the inhibition of nociceptive and nonnociceptive bladder reflexes by sacral dorsal root ganglion (DRG) stimulation in cats. Hook electrodes were placed in the right S1 and S2 DRG of cats. The bladders were infused with physiologic saline or 0.25% acetic acid (AA). Naloxone (0.1, 0.3, and 1 mg/kg), an opioid receptor antagonist, was administered intravenously. S1 or S2 DRG stimulation was applied before and after administering the drug. Multiple cystometrograms were performed to determine the effects of DRG stimulation and opioid receptors on the micturition reflex under nociceptive and non-nociceptive conditions. AA significantly (P < 0.01) reduced bladder capacity (BC). DRG stimulation at threshold (T) and 1.5 T significantly increased BC of the saline control under nociceptive and non-nociceptive conditions. When saline was infused, naloxone (0.1-1 mg/kg) significantly (P < 0.01) reduced BC; however, naloxone did not change BC during AA irritation. During saline infusion, naloxone (0.3 and 1 mg/kg) partly blocked S1 DRG stimulation-induced inhibition but had only a slight effect on S2 DRG stimulation. During AA infusion, naloxone (0.3 and 1 mg/kg) only partially blocked S1 DRG stimulation at T intensity but not during 1.5 T stimulation. However, no doses of naloxone significantly affected S2 DRG stimulation. Opioid receptors play a role in sacral DRG stimulation on non-nociceptive condition but are not involved in the inhibitory effect of stimulation in nociceptive conditions. © 2018 Wiley Periodicals, Inc.

Diagnostic ability of macular ganglion cell asymmetry for glaucoma.

PubMed

Hwang, Young Hoon; Ahn, Sang Il; Ko, Sung Ju

2015-11-01

Using spectral-domain optical coherence tomography (OCT), this study aims to investigate the glaucoma diagnostic ability of macular ganglion cell asymmetry analysis. A cross-sectional study was conducted. This study was performed to investigate glaucoma diagnostic ability of macular ganglion cell asymmetry analysis in eyes with various degrees of glaucoma. We enrolled 181 healthy eyes and 265 glaucomatous eyes. Glaucomatous eyes were subdivided into pre-perimetric, early, moderate and advanced-to-severe glaucoma based on visual field test results. For each eye, macular ganglion cell-inner plexiform layer (GCIPL) thickness was measured using OCT. Average GCIPL thickness, GCIPL thicknesses in superior and inferior hemispheres, absolute difference in GCIPL thickness between superior and inferior hemispheres and GCIPL asymmetry index calculated as the absolute value of log10 (inferior hemisphere thickness/superior hemisphere thickness) were analysed. Areas under the receiver operating characteristics curves (AUCs) of GCIPL parameter were calculated and compared. All of the GCIPL parameters showed good glaucoma diagnostic ability (AUCs ≥ 0.817, P < 0.01). AUCs of average, superior and inferior GCIPL thickness increased as the severity of glaucoma increased. GCIPL thickness difference and asymmetry index showed the highest AUCs in early and moderate glaucoma and lower AUCs in pre-perimetric and advanced-to-severe glaucoma. GCIPL thickness difference and asymmetry index showed better glaucoma diagnostic ability than other GCIPL parameters only in early stage of glaucoma (P < 0.05); in other stages, these parameters had similar to or worse glaucoma diagnostic ability than other GCIPL parameters. Macular ganglion cell asymmetry analysis showed good glaucoma diagnostic ability, especially in early-stage glaucoma. However, it has limited usefulness in other stages of glaucoma. © 2015 Royal Australian and New Zealand College of Ophthalmologists.

Cytoarchitectonic study of the trigeminal ganglion in humans.

PubMed

Krastev, Dimo Stoyanov; Apostolov, Alexander

2013-01-01

The trigeminal ganglion (TG), a cluster of pseudounipolar neurons, is located in the trigeminal impression of the temporal pyramid. It is covered by a sheath of the dura mater and arachnoid and is near the rear end of the cavernous sinus. The peripheral processes of the pseudounipolar cells are involved in the formation of the first and second branch and the sensory part of the third branch of the fifth cranial nerve, and the central ones form the sensory root of the nerve, which penetrates at the level of the middle cerebellar peduncle, aside from the pons, and terminate in the sensory nuclei of the trigeminal complex. We found that the primary sensory neurons involved in sensory innervation of the orofacial complex are a diverse group. Although they possess the general structure of pseudounipolar neurons, there are significant differences among them, seen in varying intensities of staining. Based on our investigations we classified the neurons into 7 groups, i.e. large, subdivided into light and dark, medium, also light and dark, and small light and dark, and, moreover, neurons with an irregular shape of their perikarya. Further research by applying various immunohistochemical methods will clarify whether differences in the morphological patterns of the neurons are associated with differences in the neurochemical composition of various neuronal types.

Cytoarchitectonic study of the trigeminal ganglion in humans

PubMed Central

KRASTEV, DIMO STOYANOV; APOSTOLOV, ALEXANDER

2013-01-01

The trigeminal ganglion (TG), a cluster of pseudounipolar neurons, is located in the trigeminal impression of the temporal pyramid. It is covered by a sheath of the dura mater and arachnoid and is near the rear end of the cavernous sinus. The peripheral processes of the pseudounipolar cells are involved in the formation of the first and second branch and the sensory part of the third branch of the fifth cranial nerve, and the central ones form the sensory root of the nerve, which penetrates at the level of the middle cerebellar peduncle, aside from the pons, and terminate in the sensory nuclei of the trigeminal complex. We found that the primary sensory neurons involved in sensory innervation of the orofacial complex are a diverse group. Although they possess the general structure of pseudounipolar neurons, there are significant differences among them, seen in varying intensities of staining. Based on our investigations we classified the neurons into 7 groups, i.e. large, subdivided into light and dark, medium, also light and dark, and small light and dark, and, moreover, neurons with an irregular shape of their perikarya. Further research by applying various immunohistochemical methods will clarify whether differences in the morphological patterns of the neurons are associated with differences in the neurochemical composition of various neuronal types. PMID:26527926

Virtual pathology of cervical radiculopathy based on 3D MR/CT fusion images: impingement, flattening or twisted condition of the compressed nerve root in three cases.

PubMed

Kamogawa, Junji; Kato, Osamu; Morizane, Tatsunori; Hato, Taizo

2015-01-01

There have been several imaging studies of cervical radiculopathy, but no three-dimensional (3D) images have shown the path, position, and pathological changes of the cervical nerve roots and spinal root ganglion relative to the cervical bony structure. The objective of this study was to introduce a technique that enables the virtual pathology of the nerve root to be assessed using 3D magnetic resonance (MR)/computed tomography (CT) fusion images that show the compression of the proximal portion of the cervical nerve root by both the herniated disc and the preforaminal or foraminal bony spur in patients with cervical radiculopathy. MR and CT images were obtained from three patients with cervical radiculopathy. 3D MR images were placed onto 3D CT images using a computer workstation. The entire nerve root could be visualized in 3D with or without the vertebrae. The most important characteristic evident on the images was flattening of the nerve root by a bony spur. The affected root was constricted at a pre-ganglion site. In cases of severe deformity, the flattened portion of the root seemed to change the angle of its path, resulting in twisted condition. The 3D MR/CT fusion imaging technique enhances visualization of pathoanatomy in cervical hidden area that is composed of the root and intervertebral foramen. This technique provides two distinct advantages for diagnosis of cervical radiculopathy. First, the isolation of individual vertebra clarifies the deformities of the whole root groove, including both the uncinate process and superior articular process in the cervical spine. Second, the tortuous or twisted condition of a compressed root can be visualized. The surgeon can identify the narrowest face of the root if they view the MR/CT fusion image from the posterolateral-inferior direction. Surgeons use MR/CT fusion images as a pre-operative map and for intraoperative navigation. The MR/CT fusion images can also be used as educational materials for all hospital

Accelerated retinal ganglion cell death in mice deficient in the Sigma-1 receptor

PubMed Central

Mavlyutov, Timur A.; Nickells, Robert W.

2011-01-01

Purpose The sigma-1 receptor (σR1), a ligand-operated chaperone, has been inferred to be neuroprotective in previous studies using σR1 ligands. The σR1 specificity of the protective function, however, has yet to be firmly established, due to the existence of non-σR1 targets of the ligands. Here, we used the σR1-knockout mouse (Sigmar1−/−) to demonstrate unambiguously the role of the σR1 in protecting the retinal ganglion cells against degeneration after acute damage to the optic nerve. Methods Retinal σR binding sites were labeled with radioiodinated σR ligands and analyzed by autoradiography. Localization of the σR1 was performed by indirect immunofluorescence on frozen retinal sections. Retinal ganglion cell death was induced by acute optic nerve crush in wild-type and Sigmar1−/− mice. Surviving cells in the ganglion cell layer were counted on Nissl-stained retinal whole mounts 7 days after the crush surgery. Results Photoaffinity labeling indicated the presence of the σR1 in the retina, in concentrations equivalent to those in liver tissue. Immunolabeling detected this receptor in cells of both the ganglion cell layer and the photoreceptor cell layer in wild-type retinas. Quantification of cells remaining after optic nerve crush showed that 86.8±7.9% cells remained in the wild-type ganglion cell layer, but only 68.3±3.4% survived in the Sigmar1−/−, demonstrating a significant difference between the wild-type and the Sigmar1−/− in crush-induced ganglion cell loss. Conclusions Our data indicated faster retinal ganglion cell death in Sigmar1−/− than in wild-type mice under the stresses caused by optic nerve crush, providing direct evidence for a role of the σR1 in alleviating retinal degeneration. This conclusion is consistent with the previous pharmacological studies using σR1 agonists. Thus, our study supports the idea that the σR1 is a promising therapeutic target for neurodegenerative retinal diseases, such as glaucoma. PMID

Relationship between macular ganglion cell complex thickness and macular outer retinal thickness: a spectral-domain optical coherence tomography study.

PubMed

Kita, Yoshiyuki; Kita, Ritsuko; Takeyama, Asuka; Anraku, Ayako; Tomita, Goji; Goldberg, Ivan

2013-01-01

To assess the relationship between macular ganglion cell complex and macular outer retinal thicknesses. Case-control study. Forty-two normal eyes and 91 eyes with primary open-angle glaucoma were studied. Spectral-domain optical coherence tomography (RTVue-100) was used to measure the macular ganglion cell complex and macular outer retinal thickness. Ganglion cell complex to outer retinal thickness ratio was also calculated. The relationships between the ganglion cell complex and outer retinal thicknesses and between the ganglion cell complex to outer retinal thickness ratio and outer retinal thickness were evaluated. There was a positive correlation between ganglion cell complex and outer retinal thicknesses in the normal group and the glaucoma group (r = 0.53, P < 0.001 and r = 0.42, P < 0.001, respectively). In that respect, there was no correlation between ganglion cell complex to outer retinal thickness ratio and outer retinal thickness in the both groups (r = -0.07, P = 0.657, and r = 0.04, P = 0.677, respectively). The ganglion cell complex to outer retinal thickness ratio was 55.65% in the normal group, 45.07% in the glaucoma group. This difference was statistically significant. The ganglion cell complex thickness may be affected by outer retinal thickness, and there is individual variation in the outer retinal thickness. Therefore, when determining the ganglion cell complex, it seems necessary to consider the outer retinal thickness as well. We propose the ratio as a suitable parameter to account for individual variations in outer retinal thickness. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

Digital Museum of Retinal Ganglion Cells with Dense Anatomy and Physiology.

PubMed

Bae, J Alexander; Mu, Shang; Kim, Jinseop S; Turner, Nicholas L; Tartavull, Ignacio; Kemnitz, Nico; Jordan, Chris S; Norton, Alex D; Silversmith, William M; Prentki, Rachel; Sorek, Marissa; David, Celia; Jones, Devon L; Bland, Doug; Sterling, Amy L R; Park, Jungman; Briggman, Kevin L; Seung, H Sebastian

2018-05-17

When 3D electron microscopy and calcium imaging are used to investigate the structure and function of neural circuits, the resulting datasets pose new challenges of visualization and interpretation. Here, we present a new kind of digital resource that encompasses almost 400 ganglion cells from a single patch of mouse retina. An online "museum" provides a 3D interactive view of each cell's anatomy, as well as graphs of its visual responses. The resource reveals two aspects of the retina's inner plexiform layer: an arbor segregation principle governing structure along the light axis and a density conservation principle governing structure in the tangential plane. Structure is related to visual function; ganglion cells with arbors near the layer of ganglion cell somas are more sustained in their visual responses on average. Our methods are potentially applicable to dense maps of neuronal anatomy and physiology in other parts of the nervous system. Copyright © 2018 Elsevier Inc. All rights reserved.

Adenovector GAD65 gene delivery into the rat trigeminal ganglion produces orofacial analgesia

PubMed Central

Vit, Jean-Philippe; Ohara, Peter T; Sundberg, Christopher; Rubi, Blanca; Maechler, Pierre; Liu, Chunyan; Puntel, Mariana; Lowenstein, Pedro; Castro, Maria; Jasmin, Luc

2009-01-01

Background Our goal is to use gene therapy to alleviate pain by targeting glial cells. In an animal model of facial pain we tested the effect of transfecting the glutamic acid decarboxylase (GAD) gene into satellite glial cells (SGCs) of the trigeminal ganglion by using a serotype 5 adenovector with high tropisms for glial cells. We postulated that GABA produced from the expression of GAD would reduce pain behavior by acting on GABA receptors on neurons within the ganglion. Results Injection of adenoviral vectors (AdGAD65) directly into the trigeminal ganglion leads to sustained expression of the GAD65 isoform over the 4 weeks observation period. Immunohistochemical analysis showed that adenovirus-mediated GAD65 expression and GABA synthesis were mainly in SGCs. GABAA and GABAB receptors were both seen in sensory neurons, yet only GABAA receptors decorated the neuronal surface. GABA receptors were not found on SGCs. Six days after injection of AdGAD65 into the trigeminal ganglion, there was a statistically significant decrease of pain behavior in the orofacial formalin test, a model of inflammatory pain. Rats injected with control virus (AdGFP or AdLacZ) had no reduction in their pain behavior. AdGAD65-dependent analgesia was blocked by bicuculline, a selective GABAA receptor antagonist, but not by CGP46381, a selective GABAB receptor antagonist. Conclusion Transfection of glial cells in the trigeminal ganglion with the GAD gene blocks pain behavior by acting on GABAA receptors on neuronal perikarya. PMID:19656360

Adenovector GAD65 gene delivery into the rat trigeminal ganglion produces orofacial analgesia.

PubMed

Vit, Jean-Philippe; Ohara, Peter T; Sundberg, Christopher; Rubi, Blanca; Maechler, Pierre; Liu, Chunyan; Puntel, Mariana; Lowenstein, Pedro; Castro, Maria; Jasmin, Luc

2009-08-05

Our goal is to use gene therapy to alleviate pain by targeting glial cells. In an animal model of facial pain we tested the effect of transfecting the glutamic acid decarboxylase (GAD) gene into satellite glial cells (SGCs) of the trigeminal ganglion by using a serotype 5 adenovector with high tropisms for glial cells. We postulated that GABA produced from the expression of GAD would reduce pain behavior by acting on GABA receptors on neurons within the ganglion. Injection of adenoviral vectors (AdGAD65) directly into the trigeminal ganglion leads to sustained expression of the GAD65 isoform over the 4 weeks observation period. Immunohistochemical analysis showed that adenovirus-mediated GAD65 expression and GABA synthesis were mainly in SGCs. GABAA and GABAB receptors were both seen in sensory neurons, yet only GABAA receptors decorated the neuronal surface. GABA receptors were not found on SGCs. Six days after injection of AdGAD65 into the trigeminal ganglion, there was a statistically significant decrease of pain behavior in the orofacial formalin test, a model of inflammatory pain. Rats injected with control virus (AdGFP or AdLacZ) had no reduction in their pain behavior. AdGAD65-dependent analgesia was blocked by bicuculline, a selective GABAA receptor antagonist, but not by CGP46381, a selective GABAB receptor antagonist. Transfection of glial cells in the trigeminal ganglion with the GAD gene blocks pain behavior by acting on GABAA receptors on neuronal perikarya.

Generation of Functional Human Retinal Ganglion Cells with Target Specificity from Pluripotent Stem Cells by Chemically Defined Recapitulation of Developmental Mechanism.

PubMed

Teotia, Pooja; Chopra, Divyan A; Dravid, Shashank Manohar; Van Hook, Matthew J; Qiu, Fang; Morrison, John; Rizzino, Angie; Ahmad, Iqbal

2017-03-01

Glaucoma is a complex group of diseases wherein a selective degeneration of retinal ganglion cells (RGCs) lead to irreversible loss of vision. A comprehensive approach to glaucomatous RGC degeneration may include stem cells to functionally replace dead neurons through transplantation and understand RGCs vulnerability using a disease in a dish stem cell model. Both approaches require the directed generation of stable, functional, and target-specific RGCs from renewable sources of cells, that is, the embryonic stem cells and induced pluripotent stem cells. Here, we demonstrate a rapid and safe, stage-specific, chemically defined protocol that selectively generates RGCs across species, including human, by recapitulating the developmental mechanism. The de novo generated RGCs from pluripotent cells are similar to native RGCs at the molecular, biochemical, functional levels. They also express axon guidance molecules, and discriminate between specific and nonspecific targets, and are nontumorigenic. Stem Cells 2017;35:572-585. © 2016 AlphaMed Press.

Visual Field Defects and Retinal Ganglion Cell Losses in Human Glaucoma Patients

PubMed Central

Harwerth, Ronald S.; Quigley, Harry A.

2007-01-01

Objective The depth of visual field defects are correlated with retinal ganglion cell densities in experimental glaucoma. This study was to determine whether a similar structure-function relationship holds for human glaucoma. Methods The study was based on retinal ganglion cell densities and visual thresholds of patients with documented glaucoma (Kerrigan-Baumrind, et al.) The data were analyzed by a model that predicted ganglion cell densities from standard clinical perimetry, which were then compared to histologic cell counts. Results The model, without free parameters, produced accurate and relatively precise quantification of ganglion cell densities associated with visual field defects. For 437 sets of data, the unity correlation for predicted vs. measured cell densities had a coefficient of determination of 0.39. The mean absolute deviation of the predicted vs. measured values was 2.59 dB, the mean and SD of the distribution of residual errors of prediction was -0.26 ± 3.22 dB. Conclusions Visual field defects by standard clinical perimetry are proportional to neural losses caused by glaucoma. Clinical Relevance The evidence for quantitative structure-function relationships provides a scientific basis of interpreting glaucomatous neuropathy from visual thresholds and supports the application of standard perimetry to establish the stage of the disease. PMID:16769839

Expression of squid iridescence depends on environmental luminance and peripheral ganglion control.

PubMed

Gonzalez-Bellido, P T; Wardill, T J; Buresch, K C; Ulmer, K M; Hanlon, R T

2014-03-15

Squid display impressive changes in body coloration that are afforded by two types of dynamic skin elements: structural iridophores (which produce iridescence) and pigmented chromatophores. Both color elements are neurally controlled, but nothing is known about the iridescence circuit, or the environmental cues, that elicit iridescence expression. To tackle this knowledge gap, we performed denervation, electrical stimulation and behavioral experiments using the long-fin squid, Doryteuthis pealeii. We show that while the pigmentary and iridescence circuits originate in the brain, they are wired differently in the periphery: (1) the iridescence signals are routed through a peripheral center called the stellate ganglion and (2) the iridescence motor neurons likely originate within this ganglion (as revealed by nerve fluorescence dye fills). Cutting the inputs to the stellate ganglion that descend from the brain shifts highly reflective iridophores into a transparent state. Taken together, these findings suggest that although brain commands are necessary for expression of iridescence, integration with peripheral information in the stellate ganglion could modulate the final output. We also demonstrate that squid change their iridescence brightness in response to environmental luminance; such changes are robust but slow (minutes to hours). The squid's ability to alter its iridescence levels may improve camouflage under different lighting intensities.

Macroanatomical investigation of the aorticorenal ganglion in 1-day-old infant sheep.

PubMed

Klećkowska-Nawrot, J; Kaczyńska, K; Jakubowska, W

2009-06-01

The aorticorenal gland belongs to the paired splanchnic ganglion, which is the main component of the coeliac plexus. It lies near the renal artery and suprarenal gland. The research was conducted on 13 1-day-old infant sheep - eight males and five females. Based on the conducted studies, it was concluded that the aorticorenal ganglion is characterized by the variable location in relation to the abdominal aorta, renal artery, caudal vena cava and suprarenal gland (holotopy), the thoracic and lumbar segment of the vertebral column (skeletotopy) (between L(1) and L(3)) and also a different shape (elongated, round, triangular, oval) as well as variable length (the aorticorenal ganglion is longer on the left side of the body; 2.72 mm) and distance from the caudal end of the suprarenal gland (longer on the left side of the body; 8.34 mm). With regard to the sex of the animal, the ganglion is the longest on the left side in ewes (3.02 mm), while in rams it is the longest on the right side (2.68 mm). Regarding the division according to sex, the longest segment was observed on the right side in ewes (9.27 mm), and the shortest segment in rams was also on the right side (6.84 mm).

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

PubMed

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

2013-09-17

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

Oxaliplatin regulates chemotherapy induced peripheral neuropathic pain in the dorsal horn and dorsal root ganglion via the Calcineurin/NFAT pathway.

PubMed

Huang, Wan; Huang, Jingxiu; Jiang, Yu; Huang, Xuanwei; Xing, Wei; He, Yaoxuan; Ouyang, Handong

2018-05-24

The aim of this study was to investigate the mechanism of oxaliplatin in the induction of neuropathic pain as a symptom of chemotherapy-induced peripheral neuropathy (CIPN). The CIPN rat model was induced with a one-time injection of oxaliplatin, and the paw withdrawal response was determined using von Frey filaments. The paw withdrawal threshold (PWT) value was recorded and the dorsal horn (DH) and dorsal root ganglion (DRG) tissues were collected. The mRNA and protein levels of calcineurin (CaN), nuclear factor of activated T cells (NFAT), and other relevant cytokines were determined. CaN and NFAT inhibition reagents, FK506 and 11R-VIVIT, were applied in order to investigate the functions of the CaN/NFAT pathway in the neuropathic pain processes. The levels of the downstream inflammatory cytokines, TNF-α and IL-1β, were assessed by ELISA. The application of oxaliplatin reduced the value of PWT by 4 times on days 7（4±1.33）and 14（5.13±3.07）compared with the control group(14±0.91; 13.67±0.76). After treatment, the CaN mRNA level decreased and that of NFAT increased in DH and DRG tissues (P<0.05). However, treatment with FK506 and 11R-VIVIT decreased the value of PWT that had increased after oxaliplatin treatment. The expression of downstream cytokines related to the CaN/NFAT pathway increased, including CCR2, COX2, p-ERK, and p-P38 (all p<0.05). In addition, when the CaN/NFAT pathway was activated, the concentration of TNFα increased to 40pg/mg in DH tissues and 60pg/mg in DRG tissues compared with the control group, while the concentration of IL-1β increased to over 60pg/mg in DH and DRG tissues. It was the first time to prove that oxaliplatin-induced neuropathic pain was correlated to the activation of the CaN/NFAT pathway in our rat model. This finding can provide a new direction for explore the mechanism of oxaliplatin-induced neuropathic pain. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Advanced Oxidative Protein Products Cause Pain Hypersensitivity in Rats by Inducing Dorsal Root Ganglion Neurons Apoptosis via NADPH Oxidase 4/c-Jun N-terminal Kinase Pathways

PubMed Central

Ding, Ruoting; Sun, Baihui; Liu, Zhongyuan; Yao, Xinqiang; Wang, Haiming; Shen, Xing; Jiang, Hui; Chen, Jianting

2017-01-01

Pain hypersensitivity is the most common category of chronic pain and is difficult to cure. Oxidative stress and certain cells apoptosis, such as dorsal root ganglion (DRG) neurons, play an essential role in the induction and development of pain hypersensitivity. The focus of this study is at a more specific molecular level. We investigated the role of advanced oxidative protein products (AOPPs) in inducing hypersensitivity and the cellular mechanism underlying the proapoptotic effect of AOPPs. Normal rats were injected by AOPPs-Rat serum albumin (AOPPs–RSA) to cause pain hypersensitivity. Primary cultured DRG neurons were treated with increasing concentrations of AOPPs–RSA or for increasing time durations. The MTT, flow cytometry and western blot analyses were performed in the DRG neurons. A loss of mitochondrial membrane potential (MMP) and an increase in intracellular reactive oxygen species (ROS) were observed. We found that AOPPs triggered DRG neurons apoptosis and MMP loss. After AOPPs treatment, intracellular ROS generation increased in a time- and dose-dependent manner, whereas, N-acetyl-L-cysteine (NAC), a specific ROS scavenger could inhibit the ROS generation. Proapoptotic proteins, such as Bax, caspase 9/caspase 3, and PARP-1 were activated, whereas anti-apoptotic Bcl-2 protein was down-regulated. AOPPs also increased Nox4 and JNK expression. Taken together, these findings suggest that AOPPs cause pain hypersensitivity in rats, and extracellular AOPPs accumulation triggered Nox4-dependent ROS production, which activated JNK, and induced DRG neurons apoptosis by activating caspase 3 and PARP-1. PMID:28674486

Processing of central and reflex vagal drives by rat cardiac ganglion neurones: an intracellular analysis

PubMed Central

McAllen, Robin M; Salo, Lauren M; Paton, Julian F R; Pickering, Anthony E

2011-01-01

Abstract Cardiac vagal tone is an important indicator of cardiovascular health, and its loss is an independent risk factor for arrhythmias and mortality. Several studies suggest that this loss of vagal tone can occur at the cardiac ganglion but the factors affecting ganglionic transmissionin vivoare poorly understood. We have employed a novel approach allowing intracellular recordings from functionally connected cardiac vagal ganglion cells in the working heart–brainstem preparation. The atria were stabilisedin situpreserving their central neural connections, and ganglion cells (n = 32) were impaled with sharp microelectrodes. Cardiac ganglion cells with vagal synaptic inputs (spontaneous, n = 10; or electrically evoked from the vagus, n = 3) were identified as principal neurones and showed tonic firing responses to current injected to their somata. Cells lacking vagal inputs (n = 19, presumed interneurones) were quiescent but showed phasic firing responses to depolarising current. In principal cells the ongoing action potentials and EPSPs exhibited respiratory modulation, with peak frequency in post-inspiration. Action potentials arose from unitary EPSPs and autocorrelation of those events showed that each ganglion cell received inputs from a single active preganglionic source. Peripheral chemoreceptor, arterial baroreceptor and diving response activation all evoked high frequency synaptic barrages in these cells, always from the same single preganglionic source. EPSP amplitudes showed frequency dependent depression, leading to more spike failures at shorter inter-event intervals. These findings indicate that rather than integrating convergent inputs, cardiac vagal postganglionic neurones gate preganglionic inputs, so regulating the proportion of central parasympathetic tone that is transmitted on to the heart. PMID:22005679

Recurrent Cubital Tunnel Syndrome Caused by Ganglion: A Report of Nine Cases.

PubMed

Komatsu, Masatoshi; Uchiyama, Shigeharu; Kimura, Takumi; Suenaga, Naoki; Hayashi, Masanori; Kato, Hiroyuki

2018-06-01

Cubital tunnel syndrome (CuTS) is generally treated successfully by surgery and recurrent cases are rare. This study retrospectively investigated the clinical characteristics of recurrent CuTS caused by ganglion. We evaluated nine patients who were surgically treated for recurrent CuTS caused by ganglion. Age distribution at recurrence ranged from 43 to 79 years. The initial surgery for CuTS had been performed using various methods. The asymptomatic period from initial surgery to recurrence ranged from 22 to 252 months. Clinical, diagnostic imaging, and operative findings during the second surgery were analyzed. All patients were treated by anterior subcutaneous ulnar nerve transposition with ganglion resection and later examined directly within a mean of 71 months after the second surgery. The interval from recurrence to consultation was shorter than two months for eight cases. Chief complaints included numbness with or without pain in the ring and little fingers in all patients and resting pain in the medial elbow in five patients. Elbow osteoarthritis was present in all cases. Although four of 10 ganglia were palpable, ultrasonography and magnetic resonance imaging could identify all ganglia preoperatively. The ulnar nerve typically had become entrapped by the ganglion posteriorly and by fascia, scar tissue, and/or muscle anteriorly. Chief complaints and ulnar nerve function were improved in all patients following revision surgery. The acute onset of numbness with or without intolerable pain in the ring and little fingers after a long-term remission period following initial surgery for CuTS in patients with elbow osteoarthritis appears to be the characteristic clinical profile of recurrent CuTS caused by ganglion. As ganglia are often not palpable, ultrasonography and magnetic resonance imaging are recommended for accurate diagnosis.

In Vitro Analysis of the Role of Schwann Cells on Axonal Degeneration and Regeneration Using Sensory Neurons from Dorsal Root Ganglia.

PubMed

López-Leal, Rodrigo; Diaz, Paula; Court, Felipe A

2018-01-01

Sensory neurons from dorsal root ganglion efficiently regenerate after peripheral nerve injuries. These neurons are widely used as a model system to study degenerative mechanisms of the soma and axons, as well as regenerative axonal growth in the peripheral nervous system. This chapter describes techniques associated to the study of axonal degeneration and regeneration using explant cultures of dorsal root ganglion sensory neurons in vitro in the presence or absence of Schwann cells. Schwann cells are extremely important due to their involvement in tissue clearance during axonal degeneration as well as their known pro-regenerative effect during regeneration in the peripheral nervous system. We describe methods to induce and study axonal degeneration triggered by axotomy (mechanical separation of the axon from its soma) and treatment with vinblastine (which blocks axonal transport), which constitute clinically relevant mechanical and toxic models of axonal degeneration. In addition, we describe three different methods to evaluate axonal regeneration using quantitative methods. These protocols constitute a valuable tool to analyze in vitro mechanisms associated to axonal degeneration and regeneration of sensory neurons and the role of Schwann cells in these processes.

Axotomy of tributaries of the pelvic and pudendal nerves induces changes in the neurochemistry of mouse dorsal root ganglion neurons and the spinal cord.

PubMed

McCarthy, Carly J; Tomasella, Eugenia; Malet, Mariana; Seroogy, Kim B; Hökfelt, Tomas; Villar, Marcelo J; Gebhart, G F; Brumovsky, Pablo R

2016-05-01

Using immunohistochemical techniques, we characterized changes in the expression of several neurochemical markers in lumbar 4-sacral 2 (L4-S2) dorsal root ganglion (DRG) neuron profiles (NPs) and the spinal cord of BALB/c mice after axotomy of the L6 and S1 spinal nerves, major tributaries of the pelvic (targeting pelvic visceral organs) and pudendal (targeting perineum and genitalia) nerves. Sham animals were included. Expression of cyclic AMP-dependent transcription factor 3 (ATF3), calcitonin gene-related peptide (CGRP), transient receptor potential cation channel subfamily V, member 1 (TRPV1), tyrosine hydroxylase (TH) and vesicular glutamate transporters (VGLUT) types 1 and -2 was analysed seven days after injury. L6-S1 axotomy induced dramatic de novo expression of ATF3 in many L6-S1 DRG NPs, and parallel significant downregulations in the percentage of CGRP-, TRPV1-, TH- and VGLUT2-immunoreactive (IR) DRG NPs, as compared to their expression in uninjured DRGs (contralateral L6-S1-AXO; sham mice); VGLUT1 expression remained unaltered. Sham L6-S1 DRGs only showed a small ipsilateral increase in ATF3-IR NPs (other markers were unchanged). L6-S1-AXO induced de novo expression of ATF3 in several lumbosacral spinal cord motoneurons and parasympathetic preganglionic neurons; in sham mice the effect was limited to a few motoneurons. Finally, a moderate decrease in CGRP- and TRPV1-like-immunoreactivities was observed in the ipsilateral superficial dorsal horn neuropil. In conclusion, injury of a mixed visceral/non-visceral nerve leads to considerable neurochemical alterations in DRGs matched, to some extent, in the spinal cord. Changes in these and potentially other nociception-related molecules could contribute to pain due to injury of nerves in the abdominopelvic cavity.

Complex distribution patterns of voltage-gated calcium channel α-subunits in the spiral ganglion

PubMed Central

Chen, Wei Chun; Xue, Hui Zhong; Hsu, Yun (Lucy); Liu, Qing; Patel, Shail; Davis, Robin L.

2011-01-01

As with other elements of the peripheral auditory system, spiral ganglion neurons display specializations that vary as a function of location along the tonotopic axis. Previous work has shown that voltage-gated K+ channels and synaptic proteins show graded changes in their density that confers rapid responsiveness to neurons in the high frequency, basal region of the cochlea and slower, more maintained responsiveness to neurons in the low frequency, apical region of the cochlea. In order to understand how voltage-gated calcium channels (VGCCs) may contribute to these diverse phenotypes, we identified the VGCC α-subunits expressed in the ganglion, investigated aspects of Ca2+-dependent neuronal firing patterns, and mapped the intracellular and intercellular distributions of seven VGCC α-subunits in the spiral ganglion in vitro. Initial experiments with qRT-PCR showed that eight of the ten known VGCC α-subunits were expressed in the ganglion and electrophysiological analysis revealed firing patterns that were consistent with the presence of both LVA and HVA Ca2+ channels. Moreover, we were able to study seven of the α-subunits with immunocytochemistry, and we found that all were present in spiral ganglion neurons, and that three of them were neuron-specific (CaV1.3, CaV2.2, and CaV3.3). Further characterization of neuron-specific α-subunits showed that CaV1.3 and CaV3.3 were tonotopically-distributed, whereas CaV2.2 was uniformly distributed in apical and basal neurons. Multiple VGCC α-subunits were also immunolocalized to Schwann cells, having distinct intracellular localizations, and, significantly, appearing to distinguish putative compact0 (CaV2.3, CaV3.1) from loose (CaV1.2) myelin. Electrophysiological evaluation of spiral ganglion neurons in the presence of TEA revealed Ca2+ plateau potentials with slopes that varied proportionately with the cochlear region from which neurons were isolated. Because afterhyperpolarizations were minimal or absent under

Central Projections of Melanopsin-Expressing Retinal Ganglion Cells in the Mouse

PubMed Central

HATTAR, SAMER; KUMAR, MONICA; PARK, ALEXANDER; TONG, PATRICK; TUNG, JONATHAN; YAU, KING-WAI; BERSON, DAVID M.

2010-01-01

A rare type of ganglion cell in mammalian retina is directly photosensitive. These novel retinal photoreceptors express the photopigment melanopsin. They send axons directly to the suprachiasmatic nucleus (SCN), intergeniculate leaflet (IGL), and olivary pretectal nucleus (OPN), thereby contributing to photic synchronization of circadian rhythms and the pupillary light reflex. Here, we sought to characterize more fully the projections of these cells to the brain. By targeting tau-lacZ to the melanopsin gene locus in mice, ganglion cells that would normally express melanopsin were induced to express, instead, the marker enzyme β-galactosidase. Their axons were visualized by X-gal histochemistry or anti-β-galactosidase immunofluorescence. Established targets were confirmed, including the SCN, IGL, OPN, ventral division of the lateral geniculate nucleus (LGv), and preoptic area, but the overall projections were more widespread than previously recognized. Targets included the lateral nucleus, peri-supraoptic nucleus, and subparaventricular zone of the hypothalamus, medial amygdala, margin of the lateral habenula, posterior limitans nucleus, superior colliculus, and periaqueductal gray. There were also weak projections to the margins of the dorsal lateral geniculate nucleus. Co-staining with the cholera toxin B subunit to label all retinal afferents showed that melanopsin ganglion cells provide most of the retinal input to the SCN, IGL, and lateral habenula and much of that to the OPN, but that other ganglion cells do contribute at least some retinal input to these targets. Staining patterns after monocular enucleation revealed that the projections of these cells are overwhelmingly crossed except for the projection to the SCN, which is bilaterally symmetrical. PMID:16736474

[Impact of acupuncture to IGF-I expression in spared dorsal root ganglion of cats].

PubMed

Liu, Fen; Wang, Ting-Hua; Zhang, Yi; Hong, Sun-quan; Song, Xin-bo

2006-05-01

To explore the relationship between Insulin-like growth factor-I (IGF-I) and acupuncture promoting the spinal cord plasticity, the changes of IGF- I expressing in spared dorsal root ganglia (DRG,L6) after operation and acupuncture were investigated. 25 adult cats were divided into 5 groups: normal control group; 7th day and 14th day group after unilateral partial rhizotomy (unilateral L1-L5,L7-S2 DRG Were transected, but L6 DRG was spared); 7th day and 14th day group of acupuncture stimulating the spared DRG (electro-needle stimulation was performed by following unilateral partial root rhizotomy). Animals survived for 7 or 14 days after operation respectively. Unilateral L6 dorsal root ganglia of each group were made into 20 microm frozen sections. By immunohistochemistry ABC method, the sections were stained with specific IGF-I (1:200) antibody. The distribution and the number of IGF-I positive neurons in spared DRG (L6) that located the operated/acupuncture side of each animal were observed and counted. For 7th day group after acupuncture stiumlation, the number of IGF-I positive neurons of spared DRG of acupuncture side showed significantly more than that of 7th day operation group (P<0.05), but still less than that of normal group (P < 0.05); In 14th day group, IGF- I expression in neuron of L6 DRG also increased apparently more than that of 14th day operation group, with coming back to normal level. After acupuncture stimulating the spared DRG for 14 days, the numbers of IGF- I positive neurons in spared DRG increased significantly more than that of 7th day group after acupuncture (P<0.05). Acupuncture can significantly increase the number of IGF- I positive neurons. Our results indicate that the expression changes of IGF-I in spared DRG associate with acupuncture promoting the spinal cord plasticity.

Ganglion blocks as a treatment of pain: current perspectives

PubMed Central

Gunduz, Osman Hakan; Kenis-Coskun, Ozge

2017-01-01

The inputs from sympathetic ganglia have been known to be involved in the pathophysiology of various painful conditions such as complex regional pain syndrome, cancer pain of different origin, and coccygodynia. Sympathetic ganglia blocks are used to relieve patients who suffer from these conditions for over a century. Many numbers of local anesthetics such as bupivacaine or neurolytic agents such as alcohol can be chosen for a successful block. The agent is selected according to its duration of effect and the purpose of the injection. Most commonly used sympathetic blocks are stellate ganglion block, lumbar sympathetic block, celiac plexus block, superior hypogastric block, and ganglion Impar block. In this review, indications, methods, effectiveness, and complications of these blocks are discussed based on the data from the current literature. PMID:29276402

A Learning Model for L/M Specificity in Ganglion Cells

NASA Technical Reports Server (NTRS)

Ahumada, Albert J.

2016-01-01

An unsupervised learning model for developing LM specific wiring at the ganglion cell level would support the research indicating LM specific wiring at the ganglion cell level (Reid and Shapley, 2002). Removing the contributions to the surround from cells of the same cone type improves the signal-to-noise ratio of the chromatic signals. The unsupervised learning model used is Hebbian associative learning, which strengthens the surround input connections according to the correlation of the output with the input. Since the surround units of the same cone type as the center are redundant with the center, their weights end up disappearing. This process can be thought of as a general mechanism for eliminating unnecessary cells in the nervous system.

An Optic Nerve Crush Injury Murine Model to Study Retinal Ganglion Cell Survival

PubMed Central

Tang, Zhongshu; Zhang, Shuihua; Lee, Chunsik; Kumar, Anil; Arjunan, Pachiappan; Li, Yang; Zhang, Fan; Li, Xuri

2011-01-01

Injury to the optic nerve can lead to axonal degeneration, followed by a gradual death of retinal ganglion cells (RGCs), which results in irreversible vision loss. Examples of such diseases in human include traumatic optic neuropathy and optic nerve degeneration in glaucoma. It is characterized by typical changes in the optic nerve head, progressive optic nerve degeneration, and loss of retinal ganglion cells, if uncontrolled, leading to vision loss and blindness. The optic nerve crush (ONC) injury mouse model is an important experimental disease model for traumatic optic neuropathy, glaucoma, etc. In this model, the crush injury to the optic nerve leads to gradual retinal ganglion cells apoptosis. This disease model can be used to study the general processes and mechanisms of neuronal death and survival, which is essential for the development of therapeutic measures. In addition, pharmacological and molecular approaches can be used in this model to identify and test potential therapeutic reagents to treat different types of optic neuropathy. Here, we provide a step by step demonstration of (I) Baseline retrograde labeling of retinal ganglion cells (RGCs) at day 1, (II) Optic nerve crush injury at day 4, (III) Harvest the retinae and analyze RGC survival at day 11, and (IV) Representative result. PMID:21540827

Thalamic pain alleviated by stellate ganglion block: A case report.

PubMed

Liao, Chenlong; Yang, Min; Liu, Pengfei; Zhong, Wenxiang; Zhang, Wenchuan

2017-02-01

Thalamic pain is a distressing and treatment-resistant type of central post-stroke pain. Although stellate ganglion block is an established intervention used in pain management, its use in the treatment of thalamic pain has never been reported. A 66-year-old woman presented with a 3-year history of severe intermittent lancinating pain on the right side of the face and the right hand. The pain started from the ulnar side of the right forearm after a mild ischemic stroke in bilateral basal ganglia and left thalamus. Weeks later, the pain extended to the dorsum of the finger tips and the whole palmar surface, becoming more severe. Meanwhile, there was also pain with similar characteristics emerging on her right face, resembling atypical trigeminal neuralgia. Thalamic pain was diagnosed. After refusing the further invasive treatment, she was suggested to try stellate ganglion block. After a 3-day period of pain free (numerical rating scale: 0) postoperatively, she reported moderate to good pain relief with a numerical rating scale of about 3 to 4 lasting 1 month after the first injection. Pain as well as the quality of life was markedly improved with less dose of analgesic agents. Stellate ganglion block may be an optional treatment for thalamic pain.

Learning LM Specificity for Ganglion Cells

NASA Technical Reports Server (NTRS)

Ahumada, Albert J.

2015-01-01

Unsupervised learning models have been proposed based on experience (Ahumada and Mulligan, 1990;Wachtler, Doi, Lee and Sejnowski, 2007) that allow the cortex to develop units with LM specific color opponent receptive fields like the blob cells reported by Hubel and Wiesel on the basis of visual experience. These models used ganglion cells with LM indiscriminate wiring as inputs to the learning mechanism, which was presumed to occur at the cortical level.

Increased expression of CaV3.2 T-type calcium channels in damaged DRG neurons contributes to neuropathic pain in rats with spared nerve injury.

PubMed

Kang, Xue-Jing; Chi, Ye-Nan; Chen, Wen; Liu, Feng-Yu; Cui, Shuang; Liao, Fei-Fei; Cai, Jie; Wan, You

2018-01-01

Ion channels are very important in the peripheral sensitization in neuropathic pain. Our present study aims to investigate the possible contribution of Ca V 3.2 T-type calcium channels in damaged dorsal root ganglion neurons in neuropathic pain. We established a neuropathic pain model of rats with spared nerve injury. In these model rats, it was easy to distinguish damaged dorsal root ganglion neurons (of tibial nerve and common peroneal nerve) from intact dorsal root ganglion neurons (of sural nerves). Our results showed that Ca V 3.2 protein expression increased in medium-sized neurons from the damaged dorsal root ganglions but not in the intact ones. With whole cell patch clamp recording technique, it was found that after-depolarizing amplitudes of the damaged medium-sized dorsal root ganglion neurons increased significantly at membrane potentials of -85 mV and -95 mV. These results indicate a functional up-regulation of Ca V 3.2 T-type calcium channels in the damaged medium-sized neurons after spared nerve injury. Behaviorally, blockade of Ca V 3.2 with antisense oligodeoxynucleotides could significantly reverse mechanical allodynia. These results suggest that Ca V 3.2 T-type calcium channels in damaged medium-sized dorsal root ganglion neurons might contribute to neuropathic pain after peripheral nerve injury.

Protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion.

PubMed

Zhai, S-Q; Guo, W; Hu, Y-Y; Yu, N; Chen, Q; Wang, J-Z; Fan, M; Yang, W-Y

2011-05-01

To explore the protective effects of brain-derived neurotrophic factor on the noise-damaged cochlear spiral ganglion. Recombinant adenovirus brain-derived neurotrophic factor vector, recombinant adenovirus LacZ and artificial perilymph were prepared. Guinea pigs with audiometric auditory brainstem response thresholds of more than 75 dB SPL, measured seven days after four hours of noise exposure at 135 dB SPL, were divided into three groups. Adenovirus brain-derived neurotrophic factor vector, adenovirus LacZ and perilymph were infused into the cochleae of the three groups, variously. Eight weeks later, the cochleae were stained immunohistochemically and the spiral ganglion cells counted. The auditory brainstem response threshold recorded before and seven days after noise exposure did not differ significantly between the three groups. However, eight weeks after cochlear perfusion, the group receiving brain-derived neurotrophic factor had a significantly decreased auditory brainstem response threshold and increased spiral ganglion cell count, compared with the adenovirus LacZ and perilymph groups. When administered via cochlear infusion following noise damage, brain-derived neurotrophic factor appears to improve the auditory threshold, and to have a protective effect on the spiral ganglion cells.

Ocular anatomy, ganglion cell distribution and retinal resolution of a killer whale (Orcinus orca).

PubMed

Mass, Alla M; Supin, Alexander Y; Abramov, Andrey V; Mukhametov, Lev M; Rozanova, Elena I

2013-01-01

Retinal topography, cell density and sizes of ganglion cells in the killer whale (Orcinus orca) were analyzed in retinal whole mounts stained with cresyl violet. A distinctive feature of the killer whale's retina is the large size of ganglion cells and low cell density compared to terrestrial mammals. The ganglion cell diameter ranged from 8 to 100 µm, with the majority of cells within a range of 20-40 µm. The topographic distribution of ganglion cells displayed two spots of high cell density located in the temporal and nasal quadrants, 20 mm from the optic disk. The high-density areas were connected by a horizontal belt-like area passing below the optic disk of the retina. Peak cell densities in these areas were evaluated. Mean peak cell densities were 334 and 288 cells/mm(2) in the temporal and nasal high-density areas, respectively. With a posterior nodal distance of 19.5 mm, these high-density data predict a retinal resolution of 9.6' (3.1 cycles/deg.) and 12.6' (2.4 cycles/deg.) in the temporal and nasal areas, respectively, in water. Copyright © 2012 S. Karger AG, Basel.

Annexin 1 exerts anti-nociceptive effects after peripheral inflammatory pain through formyl-peptide-receptor-like 1 in rat dorsal root ganglion.

PubMed

Pei, L; Zhang, J; Zhao, F; Su, T; Wei, H; Tian, J; Li, M; Shi, J

2011-12-01

Annexin 1 (ANXA1) has analgesic effects in inflammatory pain. We aimed to investigate the anti-nociceptive role of ANXA1, at the dorsal root ganglion (DRG) level, through an interaction with formyl-peptide-receptor-like 1 (FPR2/ALX). Inflammatory pain was evoked by injecting complete Freund's adjuvant (CFA, 50 μl) into the hindpaw of male Sprague-Dawley rats. The distribution of ANXA1 and FPR2/ALX in L4/5 DRGs was evaluated by immunofluorescence. The expression of ANXA1 was measured by western blot. The involvement of FPR2/ALX in the anti-nociception of ANXA1 was investigated by thermal (irradiant heat) and mechanical (von Frey filament) pain tests with intrathecal (i.t.) ANXA1-derived peptide (Anxa1(2-26)), FPR2/ALX agonist 5(S)-6(R)-7-trihydroxyheptanoic-acid-methyl-ester (BML-111), and antagonist N-t-Boc-Phe-Leu-Phe-Leu-Phe (Boc1). ANXA1 and FPR2/ALX localized in the satellite glial cells and neurones in L4/5 DRGs. CFA treatment (n=20) increased ANXA1 expression in L4/5 DRGs within 7 days (P<0.01). I.T. Anxa1(2-26) (20 and 100 µg µl(-1)) and BML-111 (10 and 100 nmol) reduced CFA-induced thermal and mechanical nociception within 48 h (n=40) (P<0.05). However, i.t. Boc1 10 µg intensified inflammatory pain (P<0.05) and reversed the anti-nociceptive effect of Anxa1(2-26) (n=25) (P<0.05). Moreover, ANXA1 expression increased in L4/5 DRGs after i.t. Anxa1(2-26) (20 µg µl(-1)) (P<0.05) and BML-111 (10 nmol) (P<0.01) but decreased after i.t. Boc1 (10 and 100 µg) alone (P<0.01) or Boc1 (10 µg) co-injection with Anxa1(2-26) (20 µg µl(-1)) (P<0.05). Endogenous ANXA1 expression at the DRG level is involved in CFA-induced inflammatory pain, and i.t. ANXA1 20 µg µl(-1) produces its anti-nociceptive effect through FPR2/ALX.

Lithium alters the morphology of neurites regenerating from cultured adult spiral ganglion neurons.

PubMed

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

2013-10-01

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 0.5-2.5 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 prove

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 Central

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

2010-01-01

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 (Nav1.8), 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 Nav1.8 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 Nav1.8, 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. (J Histochem Cytochem 58:329–344, 2010) PMID:20026672

A trade-off between embryonic development rate and immune function of avian offspring is concealed by embryonic temperature

USGS Publications Warehouse

Martin, Thomas E.; Arriero, Elena; Majewska, Ania

2011-01-01

Long embryonic periods are assumed to reflect slower intrinsic development that are thought to trade off to allow enhanced physiological systems, such as immune function. Yet, the relatively rare studies of this trade-off in avian offspring have not found the expected trade-off. Theory and tests have not taken into account the strong extrinsic effects of temperature on embryonic periods of birds. Here, we show that length of the embryonic period did not explain variation in two measures of immune function when temperature was ignored, based on studies of 34 Passerine species in tropical Venezuela (23 species) and north temperate Arizona (11 species). Variation in immune function was explained when embryonic periods were corrected for average embryonic temperature, in order to better estimate intrinsic rates of development. Immune function of offspring trades off with intrinsic rates of embryonic development once the extrinsic effects of embryonic temperatures are taken into account.

Enkephalin modulation of neural transmission in the cat stellate ganglion: pharmacological actions of exogenous opiates.

PubMed

Prosdocimi, M; Finesso, M; Gorio, A

1986-11-01

Neural ganglionic transmission was studied in vivo in the cat, using closed chest anesthetized preparations. The right stellate ganglion and its branches were exposed retropleurally and prepared for electrical stimulation of pre- and postganglionic nerve fibers. The axillary artery was cannulated allowing direct administration of drugs in the arterial blood supplying the ganglion. Stimulation of postjunctional receptors could thus be obtained by local administration of selective agents. Local administration of nicotinic, muscarinic or histaminergic agents increased heart rate and blood pressure. Opiates were given either i.v. or locally through the axillary artery: we tested the effects of morphine, Leu-enkephalin (Leu-enk), Met-enkephalin (Met-enk), [D-ala2]-Met-enkephalinamide (DAME) and etorphine. When given locally, Leu-enk (from 10 micrograms), Met-enk (from 20 micrograms), DAME (from 5 micrograms) and etorphine (from 0.2 micrograms) inhibited tachycardia induced by preganglionic stimulation and reduced the amplitude of the compound action potential recorded from the postganglionic nerve. Morphine (10-200 micrograms) had no effect. On the other hand, tachycardia induced by postganglionic nerve stimulation was unaffected by opiates in the same experimental conditions. Intravenous administration of similar doses of opiates had no effect on ganglionic transmission. When tachycardia was induced by chemical stimulation of nicotinic (DMPP), muscarinic (McN-A-343-11) or histamine receptors in the stellate ganglia, opiates were still active in reducing the effect of these chemicals. These data provide evidence that exogenous opiates exert a depressing action on postsynaptic responses of sympathetic ganglia tested in vivo, although an additional action on presynaptic terminals is not excluded. As endogenous opiates are normally present in various sympathetic ganglia, including the stellate ganglion of the cat, it is possible that they play some modulatory role on

Neuroprotective Effect of Tauroursodeoxycholic Acid on N-Methyl-D-Aspartate-Induced Retinal Ganglion Cell Degeneration

PubMed Central

Fernández-Sánchez, Laura; Rondón, Netxibeth; Esquiva, Gema; Germain, Francisco; de la Villa, Pedro; Cuenca, Nicolás

2015-01-01

Retinal ganglion cell degeneration underlies the pathophysiology of diseases affecting the retina and optic nerve. Several studies have previously evidenced the anti-apoptotic properties of the bile constituent, tauroursodeoxycholic acid, in diverse models of photoreceptor degeneration. The aim of this study was to investigate the effects of systemic administration of tauroursodeoxycholic acid on N-methyl-D-aspartate (NMDA)-induced damage in the rat retina using a functional and morphological approach. Tauroursodeoxycholic acid was administered intraperitoneally before and after intravitreal injection of NMDA. Three days after insult, full-field electroretinograms showed reductions in the amplitudes of the positive and negative-scotopic threshold responses, scotopic a- and b-waves and oscillatory potentials. Quantitative morphological evaluation of whole-mount retinas demonstrated a reduction in the density of retinal ganglion cells. Systemic administration of tauroursodeoxycholic acid attenuated the functional impairment induced by NMDA, which correlated with a higher retinal ganglion cell density. Our findings sustain the efficacy of tauroursodeoxycholic acid administration in vivo, suggesting it would be a good candidate for the pharmacological treatment of degenerative diseases coursing with retinal ganglion cell loss. PMID:26379056

Visual pattern recognition based on spatio-temporal patterns of retinal ganglion cells’ activities

PubMed Central

Jing, Wei; Liu, Wen-Zhong; Gong, Xin-Wei; Gong, Hai-Qing

2010-01-01

Neural information is processed based on integrated activities of relevant neurons. Concerted population activity is one of the important ways for retinal ganglion cells to efficiently organize and process visual information. In the present study, the spike activities of bullfrog retinal ganglion cells in response to three different visual patterns (checker-board, vertical gratings and horizontal gratings) were recorded using multi-electrode arrays. A measurement of subsequence distribution discrepancy (MSDD) was applied to identify the spatio-temporal patterns of retinal ganglion cells’ activities in response to different stimulation patterns. The results show that the population activity patterns were different in response to different stimulation patterns, such difference in activity pattern was consistently detectable even when visual adaptation occurred during repeated experimental trials. Therefore, the stimulus pattern can be reliably discriminated according to the spatio-temporal pattern of the neuronal activities calculated using the MSDD algorithm. PMID:21886670

Effects of electroacupuncture at 2 and 100 Hz on rat type 2 diabetic neuropathic pain and hyperalgesia-related protein expression in the dorsal root ganglion.

PubMed

He, Xiao-Fen; Wei, Jun-Jun; Shou, Sheng-Yun; Fang, Jian-Qiao; Jiang, Yong-Liang

To investigate the analgesic effects of electroacupuncture (EA) at 2 and 100 Hz on type 2 diabetic neuropathic pain (DNP) and on the expressions of the P2X3 receptor and calcitonin gene-related peptide (CGRP) in the dorsal root ganglion (DRG). Rat type 2 DNP was induced by a high calorie and high sugar diet fed for 7 weeks, plus a single intraperitoneal injection of streptozotocin (STZ) after 5 weeks. EA at 2 and 100 Hz was carried out once every day after 7 weeks for 7 consecutive days. Body weight, serum fasting insulin (FINS), fasting blood glucose (FBG), insulin sensitivity index (ISI), and paw withdrawal latency (PWL) were measured. The expressions of L4-L6 DRG P2X3 receptors and CGRP were assessed by immunofluorescence. Type 2 DNP was successfully induced as shown by the increased body weight, FINS, and FBG, as well as the reduced ISI and PWL. Expressions of P2X3 receptors and CGRP in L4-L6 DRGs increased. EA at both 2 and 100 Hz relieved type 2 DNP, but the analgesic effect of EA was stronger at 2 Hz. P2X3 receptor expression decreased in L4-L6 DRGs following EA at 2 Hz and in L5 and L6 DRGs following EA at 100 Hz. EA at both 2 and 100 Hz down-regulated CGRP overexpression in L4-L6 DRGs. These findings indicate that EA at 2 Hz is a good option for the management of type 2 DNP. The EA effect may be related to its down-regulation of the overexpressions of the DRG P2X3 receptors and CGRP in this condition.

Effects of electroacupuncture at 2 and 100 Hz on rat type 2 diabetic neuropathic pain and hyperalgesia-related protein expression in the dorsal root ganglion*

PubMed Central

He, Xiao-fen; Wei, Jun-jun; Shou, Sheng-yun; Fang, Jian-qiao; Jiang, Yong-liang

2017-01-01

Objective: To investigate the analgesic effects of electroacupuncture (EA) at 2 and 100 Hz on type 2 diabetic neuropathic pain (DNP) and on the expressions of the P2X3 receptor and calcitonin gene-related peptide (CGRP) in the dorsal root ganglion (DRG). Methods: Rat type 2 DNP was induced by a high calorie and high sugar diet fed for 7 weeks, plus a single intraperitoneal injection of streptozotocin (STZ) after 5 weeks. EA at 2 and 100 Hz was carried out once every day after 7 weeks for 7 consecutive days. Body weight, serum fasting insulin (FINS), fasting blood glucose (FBG), insulin sensitivity index (ISI), and paw withdrawal latency (PWL) were measured. The expressions of L4–L6 DRG P2X3 receptors and CGRP were assessed by immunofluorescence. Results: Type 2 DNP was successfully induced as shown by the increased body weight, FINS, and FBG, as well as the reduced ISI and PWL. Expressions of P2X3 receptors and CGRP in L4–L6 DRGs increased. EA at both 2 and 100 Hz relieved type 2 DNP, but the analgesic effect of EA was stronger at 2 Hz. P2X3 receptor expression decreased in L4–L6 DRGs following EA at 2 Hz and in L5 and L6 DRGs following EA at 100 Hz. EA at both 2 and 100 Hz down-regulated CGRP overexpression in L4–L6 DRGs. Conclusions: These findings indicate that EA at 2 Hz is a good option for the management of type 2 DNP. The EA effect may be related to its down-regulation of the overexpressions of the DRG P2X3 receptors and CGRP in this condition. PMID:28271659

Large-scale production of embryonic red blood cells from human embryonic stem cells.

PubMed

Olivier, Emmanuel N; Qiu, Caihong; Velho, Michelle; Hirsch, Rhoda Elison; Bouhassira, Eric E

2006-12-01

To develop a method to produce in culture large number of erythroid cells from human embryonic stem cells. Human H1 embryonic stem cells were differentiated into hematopoietic cells by coculture with a human fetal liver cell line, and the resulting CD34-positive cells were expanded in vitro in liquid culture using a three-step method. The erythroid cells produced were then analyzed by light microscopy and flow cytometry. Globin expression was characterized by quantitative reverse-transcriptase polymerase chain reaction and by high-performance liquid chromatography. CD34-positive cells produced from human embryonic stem cells could be efficiently differentiated into erythroid cells in liquid culture leading to a more than 5000-fold increase in cell number. The erythroid cells produced are similar to primitive erythroid cells present in the yolk sac of early human embryos and did not enucleate. They are fully hemoglobinized and express a mixture of embryonic and fetal globins but no beta-globin. We have developed an experimental protocol to produce large numbers of primitive erythroid cells starting from undifferentiated human embryonic stem cells. As the earliest human erythroid cells, the nucleated primitive erythroblasts, are not very well characterized because experimental material at this stage of development is very difficult to obtain, this system should prove useful to answer a number of experimental questions regarding the biology of these cells. In addition, production of mature red blood cells from human embryonic stem cells is of great potential practical importance because it could eventually become an alternate source of cell for transfusion.

Ganglion cell distribution and retinal resolution in the Florida manatee, Trichechus manatus latirostris.

PubMed

Mass, Alla M; Ketten, Darlene R; Odell, Daniel K; Supin, Alexander Ya

2012-01-01

The topographic organization of retinal ganglion cells was examined in the Florida manatee (Trichechus manatus latirostris) to assess ganglion cell size and distribution and to estimate retinal resolution. The ganglion cell layer of the manatee's retina was comprised primarily of large neurons with broad intercellular spaces. Cell sizes varied from 10 to 60 μm in diameter (mean 24.3 μm). The retinal wholemounts from adult animals measured 446-501 mm(2) in area with total ganglion cell counts of 62,000-81,800 (mean 70,200). The cell density changed across the retina, with the maximum in the area below the optic disc and decreasing toward the retinal edges and in the immediate vicinity of the optic disc. The maximum cell density ranged from 235 to 337 cells per millimeter square in the adult retinae. Two wholemounts obtained from juvenile animals were 271 and 282 mm(2) in area with total cell numbers of 70,900 and 68,700, respectively (mean 69,800), that is, nearly equivalent to those of adults, but juvenile retinae consequently had maximum cell densities that were higher than those of adults: 478 and 491 cells per millimeter square. Calculations indicate a retinal resolution of ∼19' (1.6 cycles per degree) in both adult and juvenile retinae. Copyright © 2011 Wiley Periodicals, Inc.

Periosteal ganglion: a report of three new cases including MRI findings and a review of the literature.

PubMed

Okada, K; Unoki, E; Kubota, H; Abe, E; Taniwaki, M; Morita, M; Sato, K

1996-02-01

To clarify the clinicopathological features of periosteal ganglion. Three patients with periosteal ganglion were studied clinicopathologically. One patient was selected from the files of our institute and two from a consultation file. All three lesions were located over the medial aspect of the tibia. Plain radiographs showed cortical erosions of varying degrees and mild periosteal reaction of the medial side of the tibia. MR images demonstrated well-circumscribed lesions overlying the cortical bone of the tibia, shown as low-intensity areas on T1-weighted images. On T2-weighted images, lesions were homogeneous, lobulated, and showed a characteristic markedly increased signal intensity. These findings are helpful in making a diagnosis of periosteal ganglion. Each patient had an uneventful clinical course after an excision involving the wall of the ganglion, the adjoining periosteum, and the underlying sclerotic cortical bone.

Synaptic transmission in the superior cervical ganglion of the cat after reinnervation by vagus fibres

PubMed Central

Ceccarelli, B.; Clementi, F.; Mantegazza, P.

1971-01-01

1. A vagus-sympathetic anastomosis was performed in the cat by connecting end to end the cranial trunk of the vagus to the cranial end of the cervical sympathetic trunk, both severed under the ganglia. 2. Forty to sixty days after the anastomosis, the ocular signs of sympathetic paralysis (such as myosis and prolapse of the nictitating membrane) which had developed shortly after the operation, had completely disappeared, thus suggesting the recovery of synaptic transmission in the ganglion. In case of plain preganglionic denervation after the same period the ocular signs of cervical sympathetic paralysis were still present. 3. Contraction of the nictitating membrane could be induced by electrical stimulation of both the vagus preanastomotic and the sympathetic postanastomotic—preganglionic trunks. Ganglionic blocking agents induced the blockade of the `new' ganglionic synaptic function, while nicotine and pilocarpine provoked a marked contraction of the nictitating membrane. 4. Electron microscopy showed that the preganglionic regeneration of vagus fibers resulted in the formation of new synapses, mainly of axodendritic type, identical to normal ganglionic synapses. Moreover, after cutting the preanastomotic trunk of the vagus, these new ganglionic presynaptic profiles degenerated, thus proving their vagal origin. 5. During restoration of the synaptic contacts readjustment of dendritic tips occurred. ImagesText-fig. 2Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13Fig. 16Fig. 17Fig. 14Fig. 15Fig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 7Fig. 8 PMID:4326851

Spatial resolution, contrast sensitivity, and sensitivity to defocus of chicken retinal ganglion cells in vitro.

PubMed

Diedrich, Erich; Schaeffel, Frank

2009-11-01

The chicken has been extensively studied as an animal model for myopia because its eye growth is tightly controlled by visual experience. It has been found that the retina controls the axial eye growth rates depending on the amount and the sign of defocus imposed in the projected image. Glucagonergic amacrine cells were discovered that appear to encode for the sign of imposed defocus. It is not clear whether the downstream neurons, the retinal ganglion cells, still have access to this information-and whether it ultimately reaches the brain. We have analyzed the spike rates of chicken retinal ganglion cells in vitro using a microelectrode array. For this purpose, we initially defined spatial resolution and contrast sensitivity in vitro. Two classes of chicken retinal ganglions were found, depending on the linearity of their responses with increasing contrast. Responses generally declined with increasing defocus of the visual stimulus. These responses were well predicted by the modulation transfer function for a diffraction-limited defocused optical system, the first Bessel function. Thus, the studied retinal ganglion cells did not distinguish between a loss of contrast at a given spatial frequency due to reduced contrast of the stimulus pattern or because the pattern was presented out of focus. Furthermore, there was no indication that the retinal ganglion cells responded differently to defocus of either sign, at least for the cells that were recorded in this study.

Distribution of TRPV1 and TRPV2 in the human stellate ganglion and spinal cord.

PubMed

Kokubun, Souichi; Sato, Tadasu; Ogawa, Chikara; Kudo, Kai; Goto, Koju; Fujii, Yuki; Shimizu, Yoshinaka; Ichikawa, Hiroyuki

2015-03-17

Immunohistochemistry for the transient receptor potential cation channel subfamily V member 1 (TRPV1) and 2 (TRPV2) was performed on the stellate ganglion and spinal cord in human cadavers. In the stellate ganglion, 25.3% and 16.2% of sympathetic neurons contained TRPV1- and TRPV2-immunoreactivity, respectively. The cell size analysis also demonstrated that proportion of TRPV1- or TRPV2-immunoreactive (-IR) neurons among large (>600 μm(2)) sympathetic neurons (TRPV1, 30.7%; TRPV2, 27.0%) was higher than among small (<600 μm(2)) sympathetic neurons (TRPV1, 22.0%; TRPV2, 13.6%). The present study also demonstrated that 10.0% of sympathetic neurons in the stellate ganglion had pericellular TRPV2-IR nerve fibers. Fourteen percent of large neurons and 7.8% of small neurons were surrounded by TRPV2-IR nerve fibers. TRPV2-immunoreactivity was also detected in about 40% of neuronal cell bodies with pericellular TRPV2-IR nerve fibers. In the lateral horn of the human thoracic spinal cord, TRPV2-immunoreactivity was expressed by some neurons and many varicose fibers surrounding TRPV2-immunonegative neurons. TRPV2-IR pericellular fibers in the stellate ganglion may originate from the lateral horn of the spinal cord. There appears to be TRPV1- or TRPV2-IR sympathetic pathway in the human stellate ganglion and spinal cord. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Molecular Responses of the Spiral Ganglion to Aminoglycosides

ERIC Educational Resources Information Center

Balaban, Carey D.

2005-01-01

Aminoglycosides are toxic to both the inner ear hair cells and the ganglion cells that give rise to the eighth cranial nerve. According to recent studies, these cells have a repertoire of molecular responses to aminoglycoside exposure that engages multiple neuroprotective mechanisms. The responses appear to involve regulation of ionic homeostasis,…

Rules and Self-Organizing Properties of Post-embryonic Plant Organ Cell Division Patterns.

PubMed

von Wangenheim, Daniel; Fangerau, Jens; Schmitz, Alexander; Smith, Richard S; Leitte, Heike; Stelzer, Ernst H K; Maizel, Alexis

2016-02-22

Plants form new organs with patterned tissue organization throughout their lifespan. It is unknown whether this robust post-embryonic organ formation results from stereotypic dynamic processes, in which the arrangement of cells follows rigid rules. Here, we combine modeling with empirical observations of whole-organ development to identify the principles governing lateral root formation in Arabidopsis. Lateral roots derive from a small pool of founder cells in which some take a dominant role as seen by lineage tracing. The first division of the founders is asymmetric, tightly regulated, and determines the formation of a layered structure. Whereas the pattern of subsequent cell divisions is not stereotypic between different samples, it is characterized by a regular switch in division plane orientation. This switch is also necessary for the appearance of patterned layers as a result of the apical growth of the primordium. Our data suggest that lateral root morphogenesis is based on a limited set of rules. They determine cell growth and division orientation. The organ-level coupling of the cell behavior ensures the emergence of the lateral root's characteristic features. We propose that self-organizing, non-deterministic modes of development account for the robustness of plant organ morphogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Embryonic death and the creation of human embryonic stem cells.

PubMed

Landry, Donald W; Zucker, Howard A

2004-11-01

The creation of human embryonic stem cells through the destruction of a human embryo pits the value of a potential therapeutic tool against that of an early human life. This contest of values has resulted in a polarized debate that neglects areas of common interest and perspective. We suggest that a common ground for pursuing research on human embryonic stem cells can be found by reconsidering the death of the human embryo and by applying to this research the ethical norms of essential organ donation.

Therapeutic potential of stellate ganglion block in orofacial pain: a mini review.

PubMed

Jeon, Younghoon

2016-09-01

Orofacial pain is a common complaint of patients that causes distress and compromises the quality of life. It has many etiologies including trauma, interventional procedures, nerve injury, varicella-zoster (shingles), tumor, and vascular and idiopathic factors. It has been demonstrated that the sympathetic nervous system is usually involved in various orofacial pain disorders such as postherpetic neuralgia, complex regional pain syndromes, and atypical facial pain. The stellate sympathetic ganglion innervates the head, neck, and upper extremity. In this review article, the effect of stellate ganglion block and its mechanism of action in orofacial pain disorders are discussed.

The spiral ganglion: connecting the peripheral and central auditory systems

PubMed Central

Nayagam, Bryony A; Muniak, Michael A; Ryugo, David K

2011-01-01

In mammals, the initial bridge between the physical world of sound and perception of that sound is established by neurons of the spiral ganglion. The cell bodies of these neurons give rise to peripheral processes that contact acoustic receptors in the organ of Corti, and the central processes collect together to form the auditory nerve that projects into the brain. In order to better understand hearing at this initial stage, we need to know the following about spiral ganglion neurons: (1) their cell biology including cytoplasmic, cytoskeletal, and membrane properties, (2) their peripheral and central connections including synaptic structure; (3) the nature of their neural signaling; and (4) their capacity for plasticity and rehabilitation. In this report, we will update the progress on these topics and indicate important issues still awaiting resolution. PMID:21530629

The retina of the shovel-nosed ray, Rhinobatos batillum (Rhinobatidae): morphology and quantitative analysis of the ganglion, amacrine and bipolar cell populations.

PubMed

Collin, S P

1988-01-01

A light microscopy study of the retina of the shovel-nosed ray, Rhinobatos batillum (Rhinobatidae) has revealed a duplex retina with a rod to cone ratio between 4:1 and 6:1. The inner nuclear layer consists of three layers of large horizontal cells, tightly packed, stellate bipolar cells, and up to three substrata of amacrine cells. The collaterals of the many supporting Müller cells project from the inner to the outer limiting membrane and divide the retina into many subunits. The cells of the ganglion cell layer are distributed into two layers, although a large proportion of ganglion cells are also displaced into the inner plexiform and inner nuclear layers. Topographic analysis of the cells in the ganglion cell layer, inner plexiform and inner nuclear layers reveals a number of regional specializations or "areae centrales". Ganglion cells were retrogradely-labelled with cobalt-lysine from the optic nerve, and three sub-populations of neurons characterized on their soma size and position. Small (20-50 microns2), large (80-300 microns2) and giant (greater than 300 microns2) sub-populations of ganglion cells each revealed distinct retinal specializations with peak densities of 3 x 10(3), 1.25 x 10(3) and 1.57 x 10(3) cells per mm2, respectively. Topographical comparison between Nissl-stained and retrogradely-labelled ganglion cell populations have established that a maximum of 20% in the "area centralis", and 75% in unspecialized, peripheral regions of the retina are non-ganglion cells. Out of a total of 210,566 cells in the ganglion cell layer, 49% were found to be non-ganglion cells. Iso-density contour maps of amacrine and bipolar cell distributions also reveal some specializations. These cell concentrations lie in corresponding regions to areas of increased density in the large and giant ganglion cell populations, suggesting some functional association.

WenTong HuoXue Cream Can Inhibit the Reduction of the Pain-Related Molecule PLC-β3 in the Dorsal Root Ganglion of a Rat Model of Diabetic Peripheral Neuropathy

PubMed Central

Feng, Chengcheng; Xu, Lijuan; Guo, Shiyun; Chen, Qian; Shen, Yuguo; Zang, Deng

2018-01-01

WenTong HuoXue Cream (WTHX-Cream) has been shown to effectively alleviate clinical symptoms of diabetic peripheral neuropathy (DPN). This study investigated the gene and protein expression of the pain-related molecule PLC-β3 in the dorsal root ganglion (DRG) of DPN rats. 88 specific pathogen-free male Wistar rats were randomly divided into placebo (10 rats) and DPN model (78 rats) groups, and the 78 model rats were used to establish the DPN model by intraperitoneal injection of streptozotocin and were then fed a high-fat diet for 8 weeks. These rats were randomly divided into the model group, the high-, medium-, and low-dose WTHX-Cream + metformin groups, the metformin group, the capsaicin cream group, and the capsaicin cream + metformin group. After 4 weeks of continuous drug administration, the blood glucose, body weight, behavioral indexes, and sciatic nerve conduction velocity were measured. The pathological structure of the DRG and the sciatic nerve were observed. PLC-β3 mRNA and protein levels in the DRG of rats were measured. Compared with the model group, the high-dose WTHX-Cream group showed increased sciatic nerve conduction velocity, improved sciatic nerve morphological changes, and increased expression of PLC-β3 mRNA and protein in the DRG. This study showed that WTHX-Cream improves hyperalgesia symptoms of DPN by inhibiting the reduction of PLC-β3 mRNA and protein expression in the diabetic DRG of DPN rats. PMID:29599806

WenTong HuoXue Cream Can Inhibit the Reduction of the Pain-Related Molecule PLC-β3 in the Dorsal Root Ganglion of a Rat Model of Diabetic Peripheral Neuropathy.

PubMed

Feng, Chengcheng; Xu, Lijuan; Guo, Shiyun; Chen, Qian; Shen, Yuguo; Zang, Deng; Ma, Li

2018-01-01

WenTong HuoXue Cream (WTHX-Cream) has been shown to effectively alleviate clinical symptoms of diabetic peripheral neuropathy (DPN). This study investigated the gene and protein expression of the pain-related molecule PLC- β 3 in the dorsal root ganglion (DRG) of DPN rats. 88 specific pathogen-free male Wistar rats were randomly divided into placebo (10 rats) and DPN model (78 rats) groups, and the 78 model rats were used to establish the DPN model by intraperitoneal injection of streptozotocin and were then fed a high-fat diet for 8 weeks. These rats were randomly divided into the model group, the high-, medium-, and low-dose WTHX-Cream + metformin groups, the metformin group, the capsaicin cream group, and the capsaicin cream + metformin group. After 4 weeks of continuous drug administration, the blood glucose, body weight, behavioral indexes, and sciatic nerve conduction velocity were measured. The pathological structure of the DRG and the sciatic nerve were observed. PLC- β 3 mRNA and protein levels in the DRG of rats were measured. Compared with the model group, the high-dose WTHX-Cream group showed increased sciatic nerve conduction velocity, improved sciatic nerve morphological changes, and increased expression of PLC- β 3 mRNA and protein in the DRG. This study showed that WTHX-Cream improves hyperalgesia symptoms of DPN by inhibiting the reduction of PLC- β 3 mRNA and protein expression in the diabetic DRG of DPN rats.

Anti-oxidative and anti-inflammatory effects of cinnamaldehyde on protecting high glucose-induced damage in cultured dorsal root ganglion neurons of rats.

PubMed

Yang, Dan; Liang, Xiao-Chun; Shi, Yue; Sun, Qing; Liu, Di; Liu, Wei; Zhang, Hong

2016-01-01

To examine the mechanism underlying the beneficial role of cinnamaldehyde on oxidative damage and apoptosis in high glucose (HG)-induced dorsal root ganglion (DRG) neurons in vitro. HG-treated DRG neurons were developed as an in vitro model of diabetic neuropathy. The neurons were randomly divided into five groups: the control group, the HG group and the HG groups treated with 25, 50 and 100 nmol/L cinnamaldehyde, respectively. Cell viability was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and apoptosis rate was evaluated by the in situ TdT-mediated dUTP nick end labeling (TUNEL) assay. The intracellular level of reactive oxygen species (ROS) was measured with flow cytometry. Expression of nuclear factor-kappa B (NF-κB), inhibitor of κB (IκB), phosphorylated IκB (p-IκB), tumor necrosis factor (TNF)-α, interleukin-6 (IL-6) and caspase-3 were determined by western blotting and real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) were also measured by western blotting. Cinnamaldehyde reduced HG-induced loss of viability, apoptosis and intracellular generation of ROS in the DRG neurons via inhibiting NF-κB activity. The western blot assay results showed that the HG-induced elevated expressions of NF-κB, IκB and p-IκB were remarkably reduced by cinnamaldehyde treatment in a dose-dependent manner (P <0.01). The HG-induced over-expression of NF-κB p65 mRNA was remarkably attenuated after cinnamaldehyde treatment in a dose-dependent manner (P <0.01). However, the expressions of Nrf2 and HO-1 were not upregulated. Treatment with cinnamaldehyde not only attenuated caspase-3 activation and the caspase cleavage cascade in DRG neurons, but also lowered the elevated IL-6, TNF-α, cyclo-oxygenase and inducible nitric oxide synthase levels, indicating a reduction in inflammatory damage. Cinnamaldehyde protected

Effect of duration and severity of migraine on retinal nerve fiber layer, ganglion cell layer, and choroidal thickness.

PubMed

Abdellatif, Mona K; Fouad, Mohamed M

2018-03-01

To investigate the factors in migraine that have the highest significance on retinal and choroidal layers' thickness. Ninety patients with migraine and 40 age-matched healthy participants were enrolled in this observational, cross-sectional study. After full ophthalmological examination, spectral domain-optical coherence tomography was done for all patients measuring the thickness of ganglion cell layer and retinal nerve fiber layer. Enhanced depth imaging technique was used to measure the choroidal thickness. There was significant thinning in the superior and inferior ganglion cell layers, all retinal nerve fiber layer quadrants, and all choroidal quadrants (except for the central subfield) in migraineurs compared to controls. The duration of migraine was significantly correlated with ganglion cell layer, retinal nerve fiber layer, and all choroidal quadrants, while the severity of migraine was significantly correlated with ganglion cell layer and retinal nerve fiber layer only. Multiregression analysis showed that the duration of migraine is the most important determinant factor of the superior retinal nerve fiber layer quadrant (β = -0.375, p = 0.001) and in all the choroidal quadrants (β = -0.531, -0.692, -0.503, -0.461, -0.564, respectively, p  < 0.001), while severity is the most important determinant factor of inferior, nasal, and temporal retinal nerve fiber layer quadrants (β = -0.256, -0.335, -0.308; p  = 0.036, 0.005, 0.009, respectively) and the inferior ganglion cell layer hemisphere (β = -0.377 and p = 0.001). Ganglion cell layer, retinal nerve fiber layer, and choroidal thickness are significantly thinner in patients with migraine. The severity of migraine has more significant influence in the thinning of ganglion cell layer and retinal nerve fiber layer, while the duration of the disease affected the choroidal thickness more.

Clinical value of a self-designed training model for pinpointing and puncturing trigeminal ganglion.

PubMed

He, Yu-Quan; He, Shu; Shen, Yun-Xia; Qian, Cheng

2014-04-01

OBJECTIVES. A training model was designed for learners and young physicians to polish their skills in clinical practices of pinpointing and puncturing trigeminal ganglion. METHODS. A head model, on both cheeks of which the deep soft tissue was replaced by stuffed organosilicone and sponge while the superficial soft tissue, skin and the trigeminal ganglion were made of organic silicon rubber for an appearance of real human being, was made from a dried skull specimen and epoxy resin. Two physicians who had experiences in puncturing foramen ovale and trigeminal ganglion were selected to test the model, mainly for its appearance, X-ray permeability, handling of the puncture, and closure of the puncture sites. Four inexperienced physicians were selected afterwards to be trained combining Hartel's anterior facial approach with the new method of real-time observation on foramen ovale studied by us. RESULTS. Both appearance and texture of the model were extremely close to those of a real human. The fact that the skin, superficial soft tissue, deep muscles of the cheeks, and the trigeminal ganglion made of organic silicon rubber all had great elasticity resulted in quick closure and sealing of the puncture sites. The head model made of epoxy resin had similar X-ray permeability to a human skull specimen under fluoroscopy. The soft tissue was made of radiolucent material so that the training can be conducted with X-ray guidance. After repeated training, all the four young physicians were able to smoothly and successfully accomplish the puncture. CONCLUSION. This self-made model can substitute for cadaver specimen in training learners and young physicians on foramen ovale and trigeminal ganglion puncture. It is very helpful for fast learning and mastering this interventional operation skill, and the puncture accuracy can be improved significantly with our new method of real-time observation on foramen ovale.

Selective Radiofrequency Stimulation of the Dorsal Root Ganglion (DRG) as a Method for Predicting Targets for Neuromodulation in Patients With Post Amputation Pain: A Case Series.

PubMed

Hunter, Corey W; Yang, Ajax; Davis, Tim

2017-10-01

While spinal cord stimulation (SCS) has established itself as an accepted and validated treatment for neuropathic pain, there are a number of conditions where it has experienced less, long-term success: post amputee pain (PAP) being one of them. Dorsal root ganglion (DRG) stimulation has shown great promise, particularly in conditions where traditional SCS has fallen short. One major difference between DRG stimulation and traditional SCS is the ability to provide focal stimulation over targeted areas. While this may be a contributing factor to its superiority, it can also be a limitation insofar stimulating the wrong DRG(s) can lead to failure. This is particularly relevant in conditions like PAP where neuroplastic maladaptation occurs causing the pain to deviate from expected patterns, thus creating uncertainty and variability in predicting targets for stimulation. We propose selective radiofrequency (RF) stimulation of the DRG as a method for preoperatively predicting targets for neuromodulation in patients with PAP. We present four patients with PAP of the lower extremities. RF stimulation was used to selectively stimulate individual DRG's, creating areas of paresthesias to see which most closely correlated/overlapped with the painful area(s). RF stimulation to the DRG's that resulted in the desirable paresthesia coverage in the residual or the missing limb(s) was recorded as "positive." Trial DRG leads were placed based on the positive RF stimulation findings. In each patient, stimulating one or more DRG(s) produced paresthesias patterns that were contradictory to know dermatomal patterns. Upon completion of a one-week trial all four patients reported 60-90% pain relief, with coverage over the painful areas, and opted for permanent implant. Mapping the DRG via RF stimulation appears to provide improved accuracy for determining lead placement in the setting of PAP where pain patterns are known to deviate from conventional dermatomal mapping. © 2017

Modulation of A-type K+ channels by the short-chain cobrotoxin through the protein kinase C-delta isoform decreases membrane excitability in dorsal root ganglion neurons.

PubMed

Guo, Qiang; Jiang, You-Jing; Jin, Hong; Jiang, Xing-Hong; Gu, Bo; Zhang, Yi-Ming; Wang, Jian-Gong; Qin, Zheng-Hong; Tao, Jin

2013-05-01

A-type K(+) channels are crucial in controlling neuronal excitability, and their regulation in sensory neurons may alter pain sensation. In this study, we identified the functional role of cobrotoxin, the short-chain α-neurotoxin isolated from Naja atra venom, which acts in the regulation of the transient A-type K(+) currents (IA) and membrane excitability in dorsal root ganglion (DRG) neurons via the activation of the muscarinic M3 receptor (M3R). Our results showed that cobrotoxin increased IA in a concentration-dependent manner, whereas the sustained delayed rectifier K(+) currents (IDR) were not affected. Cobrotoxin did not affect the activation of IA markedly, however, it shifted the inactivation curve significantly in the depolarizing direction. The cobrotoxin-induced IA response was blocked by the M3R-selective antagonists DAU-5884 and 4-DAMP. An siRNA targeting the M3R in small DRG neurons abolished the cobrotoxin-induced IA increase. In addition, dialysis of the cells with the novel protein kinase C-delta isoform (PKC-δ) inhibitor δv1-1 or an siRNA targeting PKC-δ abolished the cobrotoxin-induced IA response, whereas inhibition of PKA or classic PKC activity elicited no such effects. Moreover, we observed a significant decrease in the firing rate of the neuronal action potential induced by M3R activation. Pretreatment of the cells with 4-aminopyridine, a selective blocker of IA, abolished this effect. Taken together, these results suggest that the short-chain cobrotoxin selectively enhances IA via a novel PKC-δ-dependent pathway. This effect occurred via the activation of M3R and might contribute to its neuronal hypoexcitability in small DRG neurons. Copyright © 2013 Elsevier Inc. All rights reserved.

[In vitro interaction of human pancreatic cancer cells and rat dorsal root ganglia: a co-culture model].

PubMed

Liu, Zhi-sheng; Wang, Ye; Li, Qiang; Zhang, Sheng-lin; Shi, Yu-rong

2012-04-01

To establish an in vitro model of perineural invasion (PNI) with co-culture of human pancreatic cancer cells and rat root ganglion, to observe the neurite outgrowth and pancreatic cancer cell proliferation and migration, and to explore the molecular basis of perineural invasion (PNI) of pancreatic cancer. Human pancreatic cancer cell line (MIA PaCa-2) and rat dorsal root ganglion (DRG) were co-cultured in Matrigel matrix to generate the PNI model. The neurite outgrowth, pancreatic cancer cell colony formation, neurite-colony contact and retrograde migration were observed under an inverted microscope. The data were analyzed with the Image-Pro Plus 5.0 system. The proliferative index (PI) was measured by immunohistochemical staining with the Ki-67 antibody. In order to determine the absorbance (A) of the pancreatic cancer cells, MTT assay was used. The apoptotic index (AI) was evaluated by flow cytometry. Neurite outgrowth was stimulated in the presence of pancreatic cancer cells. After 72 hours of the co-culture, MIA PaCa colonies co-cultured with DRG exhibited a significantly larger colony area (242.83 ± 4.92) than that of the control (182.50 ± 5.39, P < 0.001). In the MIA PaCa-2/DRG co-culture system, the neurites exhibited a trend of growing towards the pancreatic cancer cell colony. However, the pancreatic cancer cells showed a trend of retrogradely migrating to the DRG along the neurite outgrowth, when MIA PaCa-2 colonies touched the DRG. The positive rate of Ki-67 nuclear antigen was significantly higher than in the co-culture group. The PI value was higher in the experimental group (12.80%) than that in the control group (6.81%, P < 0.01). The MTT assay showed that proliferation of the pancreatic cancer cells was more active than that in the control group. Flow cytometry analysis showed that the apoptosis rate of the pancreatic cancer cell was 2.46%, significantly lower than that of the control group (4.89%, P < 0.001). An in vitro co-culture model of rat

A morphometric analysis of the superior cervical ganglion and its surrounding structures.

PubMed

Fazliogullari, Zeliha; Kilic, Cenk; Karabulut, Ahmet Kagan; Yazar, Fatih

2016-04-01

The aim of this cadaveric study was to detect the superior cervical ganglion (SCG) in a topographic manner according to vertebrae and to determine the relationship between the vertebrae, mandibular angle and longus colli muscle through morphometric analysis. The present study was performed on 40 SCG of 20 human cadavers (16 males, 4 females). The level of the SCG was determined based on the vertebrae. Ganglion length, width and thickness were detected. Distance to the adjacent vertebra, the mandibular angle and medial side of the longus colli muscle were measured. The results were evaluated statistically. The SCG existing in all cadavers was detected at the C2 vertebra level in 34 cadavers and at the C3 vertebra level in 6 cadavers. The average length, width and thickness of the SCG were 15.18 ± 1.12, 4.62 ± 0.25, and 1.83 ± 0.10 mm, respectively. No statistically significant difference was detected in terms of the distances between the ganglion and anterior tubercle of transverse processes of the vertebrae as well as the mandibular angle on either side. The distance between the SCG and the medial edge of the longus colli muscle was significantly greater on the left side in both men (p < 0.001) and women (p < 0.01). Recognition of morphometric characteristics of the SCG and detection of its location according to adjacent formations may serve as a guide for nerve blockage studies and help surgeons to preserve the ganglion in both anterior and anterolateral cervical approaches.

Integration of root phenes revealed by intensive phenotyping of root system architecture, anatomy, and physiology in cereals

NASA Astrophysics Data System (ADS)

York, Larry

2015-04-01

Food insecurity is among the greatest challenges humanity will face in the 21st century. Agricultural production in much of the world is constrained by the natural infertility of soil which restrains crops from reaching their yield potential. In developed nations, fertilizer inputs pollute air and water and contribute to climate change and environmental degradation. In poor nations low soil fertility is a primary constraint to food security and economic development. Water is almost always limiting crop growth in any system. Increasing the acquisition efficiency of soil resources is one method by which crop yields could be increased without the use of more fertilizers or irrigation. Cereals are the most widely grown crops, both in terms of land area and in yield, so optimizing uptake efficiency of cereals is an important goal. Roots are the primary interface between plant and soil and are responsible for the uptake of soil resources. The deployment of roots in space and time comprises root system architecture (RSA). Cereal RSA is a complex phenotype that aggregates many elemental phenes (elemental units of phenotype). Integration of root phenes will be determined by interactions through their effects on soil foraging and plant metabolism. Many architectural, metabolic, and physiological root phenes have been identified in maize, including: nodal root number, nodal root growth angle, lateral root density, lateral root length, aerenchyma, cortical cell size and number, and nitrate uptake kinetics. The utility of these phenes needs confirmation in maize and in other cereals. The maize root system is composed of an embryonic root system and nodal roots that emerge in successive whorls as the plant develops, and is similar to other cereals. Current phenotyping platforms often ignore the inner whorls and instead focus on the most visible outer whorls after excavating a maize root crown from soil. Here, an intensive phenotyping platform evaluating phenes of all nodal root

Changes in ganglion cell physiology during retinal degeneration influence excitability by prosthetic electrodes

NASA Astrophysics Data System (ADS)

Cho, Alice; Ratliff, Charles; Sampath, Alapakkam; Weiland, James

2016-04-01

Objective. Here we investigate ganglion cell physiology in healthy and degenerating retina to test its influence on threshold to electrical stimulation. Approach. Age-related Macular Degeneration and Retinitis Pigmentosa cause blindness via outer retinal degeneration. Inner retinal pathways that transmit visual information to the central brain remain intact, so direct electrical stimulation from prosthetic devices offers the possibility for visual restoration. Since inner retinal physiology changes during degeneration, we characterize physiological properties and responses to electrical stimulation in retinal ganglion cells (RGCs) of both wild type mice and the rd10 mouse model of retinal degeneration. Main results. Our aggregate results support previous observations that elevated thresholds characterize diseased retinas. However, a physiology-driven classification scheme reveals distinct sub-populations of ganglion cells with thresholds either normal or strongly elevated compared to wild-type. When these populations are combined, only a weakly elevated threshold with large variance is observed. The cells with normal threshold are more depolarized at rest and exhibit periodic oscillations. Significance. During degeneration, physiological changes in RGCs affect the threshold stimulation currents required to evoke action potentials.

Periosteal ganglion: a cause of cortical bone erosion.

PubMed

McCarthy, E F; Matz, S; Steiner, G C; Dorfman, H D

1983-01-01

Three cases of periosteal ganglia of long bones are presented. These lesions are produced by mucoid degeneration and cyst formation of the periosteum to produce external cortical erosion and reactive periosteal new bone. They are not associated with a soft tissue ganglion or an intraosseous lesion. They may radiologically mimic other periosteal lesions or soft tissue neoplasms which erode bone.

Epibatidine, an alkaloid from the poison frog Epipedobates tricolor, is a powerful ganglionic depolarizing agent.

PubMed

Fisher, M; Huangfu, D; Shen, T Y; Guyenet, P G

1994-08-01

Epibatidine, a newly discovered alkaloid from the skin of Dendrobatidae frogs, has structural similarities to nicotine. We examined the effects of epibatidine on cardiorespiratory function and ganglionic synaptic transmission. Superior cervical or splanchnic sympathetic nerve discharge (sSND) and phrenic nerve discharge (PND) were recorded along with arterial pressure (AP) in urethane-anesthetized, paralyzed and artificially ventilated rats. Epibatidine administered i.v. at low doses (0.5-2 micrograms/kg) produced a transient increase in AP and sSND, followed by a decrease and return to baseline; this low dose of epibatidine also produced a dose-dependent increase in PND. At high doses (cumulative dose of 8-16 micrograms/kg), epibatidine produced bradycardia, a profound depression in sSND and a transient elimination of PND. After i.v. administration of the ganglionic blocker chlorisondamine (5 mg/kg), AP was still increased by 1 microgram/kg epibatidine (+39 +/- 11 mm Hg). This pressor effect was not altered by pretreatment with the alpha-1 adrenergic antagonist phentolamine (+40 +/- 10 mm Hg); however, it was blocked by additional pretreatment with the vasopressin antagonist [beta-mercapto-beta,beta-cyclopentamethylenepropiony1, O-ET-Tyr2,Val4,Arg8]vasopressin (50 micrograms/kg i.v.; +2 +/- 0.4 mm Hg). Low doses of epibatidine (0.5-2 micrograms/kg) produced firing of postganglionic neurons in a decentralized ganglion preparation and potentiated synaptic transmission; at high doses (cumulative dose of 8-16 micrograms/kg), the alkaloid blocked ganglionic synaptic transmission. These results suggest that epibatidine is a potent agonist of ganglionic nicotinic receptors and that the alkaloid elicits cardiorespiratory effects similar to those of nicotine.

One-day high-fat diet induces inflammation in the nodose ganglion and hypothalamus of mice.

PubMed

Waise, T M Zaved; Toshinai, Koji; Naznin, Farhana; NamKoong, Cherl; Md Moin, Abu Saleh; Sakoda, Hideyuki; Nakazato, Masamitsu

2015-09-04

A high-fat diet (HFD) induces inflammation in systemic organs including the hypothalamus, resulting in obesity and diabetes. The vagus nerve connects the visceral organs and central nervous system, and the gastric-derived orexigenic peptide ghrelin transmits its starvation signals to the hypothalamus via the vagal afferent nerve. Here we investigated the inflammatory response in vagal afferent neurons and the hypothalamus in mice following one day of HFD feeding. This treatment increased the number of macrophages/microglia in the nodose ganglion and hypothalamus. Furthermore, one-day HFD induced expression of Toll-like receptor 4 in the goblet cells of the colon and upregulated mRNA expressions of the proinflammatory biomarkers Emr1, Iba1, Il6, and Tnfα in the nodose ganglion and hypothalamus. Both subcutaneous administration of ghrelin and celiac vagotomy reduced HFD-induced inflammation in these tissues. HFD intake triggered inflammatory responses in the gut, nodose ganglion, and subsequently in the hypothalamus within 24 h. These findings suggest that the vagal afferent nerve may transfer gut-derived inflammatory signals to the hypothalamus via the nodose ganglion, and that ghrelin may protect against HFD-induced inflammation. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Ganglion Cell and Displaced Amacrine Cell Density Distribution in the Retina of the Howler Monkey (Alouatta caraya)

PubMed Central

Muniz, José Augusto Pereira Carneiro; de Athaide, Luana Modesto; Gomes, Bruno Duarte; Finlay, Barbara L.; Silveira, Luiz Carlos de Lima

2014-01-01

Unlike all other New World (platyrrine) monkeys, both male and female howler monkeys (Alouatta sp.) are obligatory trichromats. In all other platyrrines, only females can be trichromats, while males are always dichromats, as determined by multiple behavioral, electrophysiological, and genetic studies. In addition to obligatory trichromacy, Alouatta has an unusual fovea, with substantially higher peak cone density in the foveal pit than every other diurnal anthropoid monkey (both platyrrhines and catarrhines) and great ape yet examined, including humans. In addition to documenting the general organization of the retinal ganglion cell layer in Alouatta, the distribution of cones is compared to retinal ganglion cells, to explore possible relationships between their atypical trichromacy and foveal specialization. The number and distribution of retinal ganglion cells and displaced amacrine cells were determined in six flat-mounted retinas from five Alouatta caraya. Ganglion cell density peaked at 0.5 mm between the fovea and optic nerve head, reaching 40,700–45,200 cells/mm2. Displaced amacrine cell density distribution peaked between 0.5–1.75 mm from the fovea, reaching mean values between 2,050–3,100 cells/mm2. The mean number of ganglion cells was 1,133,000±79,000 cells and the mean number of displaced amacrine cells was 537,000±61,800 cells, in retinas of mean area 641±62 mm2. Ganglion cell and displaced amacrine cell density distribution in the Alouatta retina was consistent with that observed among several species of diurnal Anthropoidea, both platyrrhines and catarrhines. The principal alteration in the Alouatta retina appears not to be in the number of any retinal cell class, but rather a marked gradient in cone density within the fovea, which could potentially support high chromatic acuity in a restricted central region. PMID:25546077

Enkephalin-containing neurons in the inferior mesenteric ganglion projecting to the distal colon of cat: evidence from combined retrograde tracing by fluorescent microspheres and immunohistochemistry.

PubMed

Bagnol, D; Jule, Y; Kirchner, G; Cupo, A; Roman, C

1993-02-01

Retrograde tracing with rhodamine fluorescent microspheres combined with fluorescein immunolabelling of methionine-enkephalin showed the presence of enkephalin-like material in neurons of the inferior mesenteric ganglion (sympathetic prevertebral ganglion) projecting to the distal colon in cat. Two weeks after injecting the microspheres into the wall of the distal colon, the inferior mesenteric ganglion was dissected out and incubated for 24 hours in a colchicine-containing culture medium in order to facilitate the detection of enkephalins in the soma of ganglion neurons. It was observed that retrogradely labelled ganglion cells contained enkephalin-like immunoreactive material. These ganglion cells corresponded to enkephalin-like postganglionic neurons, the terminals of which were located inside the wall of the distal colon. These enkephalin-like neurons were numerous and scattered throughout the ganglion. Sometimes enkephalin-like immunoreactive fibers, probably originating from spinal preganglionic neurons, ran close to immunoreactive and non-immunoreactive retrogradely labelled ganglion cells. This suggests that enkephalin-like immunoreactive fibers may make synaptic connections with enkephalin-like and non-enkephalin-like postganglionic neurons projecting to the distal colon. The present study establishes for the first time the existence of an enkephalin-like postganglionic pathway to the digestive tract originating from a sympathetic prevertebral ganglion. This finding indicates that the enkephalinergic innervation of the cat digestive tract may have at least two possible sources: (i) the sympathetic prevertebral ganglia; and (ii) the enteric nervous ganglia.

Functional interdependence of neurons in a single canine intrinsic cardiac ganglionated plexus

PubMed Central

Thompson, G W; Collier, K; Ardell, J L; Kember, G; Armour, J A

2000-01-01

To determine the activity characteristics displayed by different subpopulations of neurons in a single intrinsic cardiac ganglionated plexus, the behaviour and co-ordination of activity generated by neurons in two loci of the right atrial ganglionated plexus (RAGP) were evaluated in 16 anaesthetized dogs during basal states as well as in response to increasing inputs from ventricular sensory neurites. These sub-populations of right atrial neurons received afferent inputs from sensory neurites in both ventricles that were responsive to local mechanical stimuli and the nitric oxide donor nitroprusside. Neurons in at least one RAGP locus were activated by epicardial application of veratridine, bradykinin, the β1-adrenoceptor agonist prenaterol or glutamate. Epicardial application of angiotensin II, the selective β2-adrenoceptor agonist terbutaline and selective α-adrenoceptor agonists elicited inconsistent neuronal responses. The activity generated by both populations of atrial neurons studied over 5 min periods during basal states displayed periodic coupled behaviour (cross-correlation coefficients of activities that reached, on average, 0·88 ± 0·03; range 0·71–1) for 15–30 s periods of time. These periods of coupled activity occurred every 30–50 s during basal states, as well as when neuronal activity was enhanced by chemical activation of their ventricular sensory inputs. These results indicate that neurons throughout one intrinsic cardiac ganglionated plexus receive inputs from mechano- and chemosensory neurites located in both ventricles. That such neurons respond to multiple chemical stimuli, including those liberated from adjacent adrenergic efferent nerve terminals, indicates the complexity of the integrative processing of information that occurs within the intrinsic cardiac nervous system. It is proposed that the interdependent activity displayed by populations of neurons in different regions of one intrinsic cardiac ganglionated plexus

Brn3a/Pou4f1 Regulates Dorsal Root Ganglion Sensory Neuron Specification and Axonal Projection into the Spinal Cord

PubMed Central

Zou, Min; Li, Shengguo; Klein, William H.; Xiang, Mengqing

2012-01-01

The sensory neurons of the dorsal root ganglia (DRG) must project accurately to their central targets to convey proprioceptive, nociceptive and mechanoreceptive information to the spinal cord. How these different sensory modalities and central connectivities are specified and coordinated still remains unclear. Given the expression of the POU homeodomain transcription factors Brn3a/Pou4f1 and Brn3b/Pou4f2 in DRG and spinal cord sensory neurons, we determined the subtype specification of DRG and spinal cord sensory neurons as well as DRG central projections in Brn3a and Brn3b single and double mutant mice. Inactivation of either or both genes causes no gross abnormalities in early spinal cord neurogenesis; however, in Brn3a single and Brn3a;Brn3b double mutant mice, sensory afferent axons from the DRG fail to form normal trajectories in the spinal cord. The TrkA+ afferents remain outside the dorsal horn and fail to extend into the spinal cord, while the projections of TrkC+ proprioceptive afferents into the ventral horn are also impaired. Moreover, Brn3a mutant DRGs are defective in sensory neuron specification, as marked by the excessive generation of TrkB+ and TrkC+ neurons as well as TrkA+/TrkB+ and TrkA+/TrkC+ double positive cells at early embryonic stages. At later stages in the mutant, TrkB+, TrkC+ and parvalbumin+ neurons diminish while there is a significant increase of CGRP+ and c-ret+ neurons. In addition, Brn3a mutant DRGs display a dramatic down-regulation of Runx1 expression, suggesting that the regulation of DRG sensory neuron specification by Brn3a is mediated in part by Runx1. Our results together demonstrate a critical role for Brn3a in generating DRG sensory neuron diversity and regulating sensory afferent projections to the central targets. PMID:22326227

Protective effect of oestradiol in the coeliac ganglion against ovarian apoptotic mechanism on dioestrus.

PubMed

Cynthia, Bronzi; Cristina, Daneri Becerra; Adriana, Vega Orozco; Belén, Delsouc María; María, Rastrilla Ana; Marilina, Casais; Zulema, Sosa

2013-05-01

The aims of this work were to investigate if oestradiol 10(-8)M in the incubation media of either the ovary alone (OV) or the ganglion compartment of an ex vivo coeliac ganglion-superior ovarian nerve-ovary system (a) modifies the release of ovarian progesterone (P4) and oestradiol (E2) on dioestrus II, and (b) modifies the ovarian gene expression of 3β-HSD and 20α-HSD enzymes and markers of apoptosis. The concentration of ovarian P4 release was measured in both experimental schemes, and ovarian P4 and E2 in the ex vivo system by RIA at different times. The expression of 3β-hydroxysteroid dehydrogenase, 20α-hydroxysteroid dehydrogenase and antiapoptotic bcl-2 and proapoptotic bax by RT-PCR were determined. E2 added in the coeliac ganglion caused an increase in the ovarian release of the P4, E2 and 3β-HSD, while in the ovary incubation alone it decreased P4 and 3β-HSD but increased and 20α-HSD and bax/bcl-2 ratio. It is concluded that through a direct effect on the ovary, E2 promotes luteal regression in DII rats, but the addition of E2 in the coeliac ganglion does not have the same effect. The peripheral nervous system, through the superior ovarian nerve, has a protective effect against the apoptotic mechanism on DII. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Effects on survival of shRNA mediated APE/Ref1 gene silencing in rat spiral ganglion cells in oxidative stress].

PubMed

Jiang, Zhendong; Zhong, Cheng; Li, Taijun; Xiang, Zhaolan; Zhang, Xueyuan

2014-02-01

To investigate the effects of reducing APE/Ref1 expression in the cultures of rat spiral ganglion cells with oxidative damage induced by H(2)O(2). Primary cultured rat spiral ganglion cells were infected with small interfering RNA to APE/Ref1 (Ape1siRNA) for 72 h, followed by treating with H(2)O(2) (0, 10, 25, 50, 100 and 300 µmol/L) for 1 h , and then cultured in normal medium for 24 h. Western blot were used to detect the level of APE/Ref1 protein and phosphorylation of histone protein H2AX in the infected cells. The caspase3 activation was tested by spectrophotometric method . The cell viability was determined by MTT and the apoptosis of spiral ganglion cells was determined by terminal-deoxynucleotidyl transferase mediated nick and labeling (TUNEL). Western blot showed that infection with Ape1siRNA resulted in APE/Ref1 reduced expression in the spiral ganglion cells. Exposing spiral ganglion cultures with reduced expression of APE/Ref1 to H(2)O(2) (50, 100, 300 µmol/L) for 1 h resulted in increasing in the phosphorylation of histone protein H2AX. The reduction in APE/Ref1 significantly reduced cell viability in cultures 24 h after 1 h expression to 50-300 µmol/L H(2)O(2). The apoptosis of cells and caspase 3 activity was detected significantly improved. The induced of APE/Ref1 results in significantly decrease in spiral ganglion cells viability in oxidative stress. The repairing function of APE/Ref1 is necessary for optimal levels of neuronal rat spiral ganglion cells survival.

Altered glucose transport to utero-embryonic unit in relation to delayed embryonic development in the Indian short-nosed fruit bat, Cynopterus sphinx.

PubMed

Arnab, Banerjee; Amitabh, Krishna

2011-02-10

The aim of this study was to compare the changes in concentration of glucose and glucose transporters (GLUTs) in the utero-embryonic unit, consisting of decidua, trophoblast and embryo, during delayed and non-delayed periods to understand the possible cause of delayed embryonic development in Cynopterus sphinx. The results showed a significantly decreased concentration of glucose in the utero-embryonic unit due to decline in the expression of insulin receptor (IR) and GLUT 3, 4 and 8 proteins in the utero-embryonic unit during delayed period. The in vitro study showed suppressive effect of insulin on expression of GLUTs 4 and 8 in the utero-embryonic unit and a significant positive correlation between the decreased amount of glucose consumed by the utero-embryonic unit and decreased expression of GLUTs 4 (r=0.99; p<0.05) and 8 (r=0.98; p<0.05). The in vivo study showed expression of IR and GLUT 4 proteins in adipose tissue during November suggesting increased transport of glucose to adipose tissue for adipogenesis. This study showed increased expression of HSL and OCTN2 and increased availability of l-carnitine to utero-embryonic unit suggesting increased transport of fatty acid to utero-embryonic unit during the period of delayed embryonic development. Hence it appears that due to increased transport of glucose for adipogenesis prior to winter, glucose utilization by utero-embryonic unit declines and this may be responsible for delayed embryonic development in C. sphinx. Increased supply of fatty acid to the delayed embryo may be responsible for its survival under low glucose condition but unable to promote embryonic development in C. sphinx. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

TIME FOR COFFEE controls root meristem size by changes in auxin accumulation in Arabidopsis

PubMed Central

Lu, Ying-Tang

2014-01-01

Roots play important roles in plant survival and productivity as they not only anchor the plants in the soil but are also the primary organ for the uptake of nutrients from the outside. The growth and development of roots depend on the specification and maintenance of the root meristem. Here, we report a previously unknown role of TIME FOR COFFEE (TIC) in controlling root meristem size in Arabidopsis. The results showed that loss of function of TIC reduced root meristem length and cell number by decreasing the competence of meristematic cells to divide. This was due to the repressed expression of PIN genes for decreased acropetal auxin transport in tic-2, leading to low auxin accumulation in the roots responsible for reduced root meristem, which was verified by exogenous application of indole-3-acetic acid. Downregulated expression of PLETHORA1 (PLT1) and PLT2, key transcription factors in mediating the patterning of the root stem cell niche, was also assayed in tic-2. Similar results were obtained with tic-2 and wild-type plants at either dawn or dusk. We also suggested that the MYC2-mediated jasmonic acid signalling pathway may not be involved in the regulation of TIC in controlling the root meristem. Taken together, these results suggest that TIC functions in an auxin–PLTs loop for maintenance of post-embryonic root meristem. PMID:24277277

Intracochlear electrical stimulation suppresses apoptotic signaling in rat spiral ganglion neurons after deafening in vivo.

PubMed

Kopelovich, Jonathan C; Cagaanan, Alain P; Miller, Charles A; Abbas, Paul J; Green, Steven H

2013-11-01

To establish the intracellular consequences of electrical stimulation to spiral ganglion neurons after deafferentation. Here we use a rat model to determine the effect of both low and high pulse rate acute electrical stimulation on activation of the proapoptotic transcription factor Jun in deafferented spiral ganglion neurons in vivo. Experimental animal study. Hearing research laboratories of the University of Iowa Departments of Biology and Otolaryngology. A single electrode was implanted through the round window of kanamycin-deafened rats at either postnatal day 32 (P32, n = 24) or P60 (n = 22) for 4 hours of stimulation (monopolar, biphasic pulses, amplitude twice electrically evoked auditory brainstem response [eABR] threshold) at either 100 or 5000 Hz. Jun phosphorylation was assayed by immunofluorescence to quantitatively assess the effect of electrical stimulation on proapoptotic signaling. Jun phosphorylation was reliably suppressed by 100 Hz stimuli in deafened cochleae of P32 but not P60 rats. This effect was not significant in the basal cochlear turns. Stimulation frequency may be consequential: 100 Hz was significantly more effective than was 5 kHz stimulation in suppressing phospho-Jun. Suppression of Jun phosphorylation occurs in deafferented spiral ganglion neurons after only 4 hours of electrical stimulation. This finding is consistent with the hypothesis that electrical stimulation can decrease spiral ganglion neuron death after deafferentation.

Biofunctionalized peptide-based hydrogels provide permissive scaffolds to attract neurite outgrowth from spiral ganglion neurons.

PubMed

Frick, Claudia; Müller, Marcus; Wank, Ute; Tropitzsch, Anke; Kramer, Benedikt; Senn, Pascal; Rask-Andersen, Helge; Wiesmüller, Karl-Heinz; Löwenheim, Hubert

2017-01-01

Cochlear implants (CI) allow for hearing rehabilitation in patients with sensorineural hearing loss or deafness. Restricted CI performance results from the spatial gap between spiral ganglion neurons and the CI, causing current spread that limits spatially restricted stimulation and impairs frequency resolution. This may be substantially improved by guiding peripheral processes of spiral ganglion neurons towards and onto the CI electrode contacts. An injectable, peptide-based hydrogel was developed which may provide a permissive scaffold to facilitate neurite growth towards the CI. To test hydrogel capacity to attract spiral ganglion neurites, neurite outgrowth was quantified in an in vitro model using a custom-designed hydrogel scaffold and PuraMatrix ® . Neurite attachment to native hydrogels is poor, but significantly improved by incorporation of brain-derived neurotrophic factor (BDNF), covalent coupling of the bioactive laminin epitope IKVAV and the incorporation a full length laminin to hydrogel scaffolds. Incorporation of full length laminin protein into a novel custom-designed biofunctionalized hydrogel (IKVAV-GGG-SIINFEKL) allows for neurite outgrowth into the hydrogel scaffold. The study demonstrates that peptide-based hydrogels can be specifically biofunctionalized to provide a permissive scaffold to attract neurite outgrowth from spiral ganglion neurons. Such biomaterials appear suitable to bridge the spatial gap between neurons and the CI. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel model for rapid induction of apoptosis in spiral ganglions of mice.

PubMed

Lee, Ji Eun; Nakagawa, Takayuki; Kim, Tae Soo; Iguchi, Fukuichiro; Endo, Tsuyoshi; Dong, Youyi; Yuki, Kazuo; Naito, Yasushi; Lee, Sang Heun; Ito, Juichi

2003-06-01

The survival of the spiral ganglion (SG) is a critical issue in preservation of hearing. Research on topics related to this issue requires a mouse experimental model because such a model has advantages including use of genetic information and knockout or "knockin" mice. Thus, the aim of the study was to establish a mouse model for induction of apoptosis of SG neurons with a definite time course. Laboratory study using experimental animals. C57BL/6 mice were used as experimental animals and were subjected to direct application of cisplatin into the inner ear. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and immunostaining for Neurofilament 200-kD (NF) and peripherin were used for analysis of SG degeneration. In addition, generation of peroxynitrite in affected spiral ganglions was examined by immunostaining for nitrotyrosine. Cellular location of activated caspase-9 and cytochrome-c in dying SG neurons were examined for analysis of cell death pathway. The TUNEL assay and immunohistochemical analysis for NF and peripherin indicated that type I neurons in spiral ganglions were deleted through the apoptotic pathway over time. Spiral ganglion neurons treated with cisplatin exhibited expression of nitrotyrosine, indicating induction of peroxynitrite by cisplatin. In dying SG neurons, expression of activated caspase-9 and translocation of cytochrome-c from mitochondria to cytoplasm were observed, indicating the mitochondrial pathway of apoptosis. The predictable fashion of induction of apoptosis in SG neurons over a well-defined time course in the model in the study will aid studies of the molecular mechanism of cell death and elucidation of a strategy for prevention of SG degeneration.

Electromagnetic radiation (Wi-Fi) and epilepsy induce calcium entry and apoptosis through activation of TRPV1 channel in hippocampus and dorsal root ganglion of rats.

PubMed

Ghazizadeh, Vahid; Nazıroğlu, Mustafa

2014-09-01

Incidence rates of epilepsy and use of Wi-Fi worldwide have been increasing. TRPV1 is a Ca(2+) permeable and non-selective channel, gated by noxious heat, oxidative stress and capsaicin (CAP). The hyperthermia and oxidant effects of Wi-Fi may induce apoptosis and Ca(2+) entry through activation of TRPV1 channel in epilepsy. Therefore, we tested the effects of Wi-Fi (2.45 GHz) exposure on Ca(2+) influx, oxidative stress and apoptosis through TRPV1 channel in the murine dorsal root ganglion (DRG) and hippocampus of pentylentetrazol (PTZ)-induced epileptic rats. Rats in the present study were divided into two groups as controls and PTZ. The PTZ groups were divided into two subgroups namely PTZ + Wi-Fi and PTZ + Wi-Fi + capsazepine (CPZ). The hippocampal and DRG neurons were freshly isolated from the rats. The DRG and hippocampus in PTZ + Wi-Fi and PTZ + Wi-Fi + CPZ groups were exposed to Wi-Fi for 1 hour before CAP stimulation. The cytosolic free Ca(2+), reactive oxygen species production, apoptosis, mitochondrial membrane depolarization, caspase-3 and -9 values in hippocampus were higher in the PTZ group than in the control although cell viability values decreased. The Wi-Fi exposure induced additional effects on the cytosolic Ca(2+) increase. However, pretreatment of the neurons with CPZ, results in a protection against epilepsy-induced Ca(2+) influx, apoptosis and oxidative damages. In results of whole cell patch-clamp experiments, treatment of DRG with Ca(2+) channel antagonists [thapsigargin, verapamil + diltiazem, 2-APB, MK-801] indicated that Wi-Fi exposure induced Ca(2+) influx via the TRPV1 channels. In conclusion, epilepsy and Wi-Fi in our experimental model is involved in Ca(2+) influx and oxidative stress-induced hippocampal and DRG death through activation of TRPV1 channels, and negative modulation of this channel activity by CPZ pretreatment may account for the neuroprotective activity against oxidative stress.

Immediate Nerve Transfer for Treatment of Peroneal Nerve Palsy Secondary to an Intraneural Ganglion: Case Report and Review.

PubMed

Ratanshi, Imran; Clark, Tod A; Giuffre, Jennifer L

2018-05-01

Intraneural ganglion cysts, which occur within the common peroneal nerve, are a rare cause of foot drop. The current standard of treatment for intraneural ganglion cysts involving the common peroneal nerve involves (1) cyst decompression and (2) ligation of the articular nerve branch to prevent recurrence. Nerve transfers are a time-dependent strategy for recovering ankle dorsiflexion in cases of high peroneal nerve palsy; however, this modality has not been performed for intraneural ganglion cysts involving the common peroneal nerve. We present a case of common peroneal nerve palsy secondary to an intraneural ganglion cyst occurring in a 74-year-old female. The patient presented with a 5-month history of pain in the right common peroneal nerve distribution and foot drop. The patient underwent simultaneous cyst decompression, articular nerve branch ligation, and nerve transfer of the motor branch to flexor hallucis longus to a motor branch of anterior tibialis muscle. At final follow-up, the patient demonstrated complete (M4+) return of ankle dorsiflexion, no pain, no evidence of recurrence and was able to bear weight without the need for orthotic support. Given the minimal donor site morbidity and recovery of ankle dorsiflexion, this report underscores the importance of considering early nerve transfers in cases of high peroneal neuropathy due to an intraneural ganglion cyst.

The morphology and classification of α ganglion cells in the rat retinae: a fractal analysis study.

PubMed

Jelinek, Herbert F; Ristanović, Dušan; Milošević, Nebojša T

2011-09-30

Rat retinal ganglion cells have been proposed to consist of a varying number of subtypes. Dendritic morphology is an essential aspect of classification and a necessary step toward understanding structure-function relationships of retinal ganglion cells. This study aimed at using a heuristic classification procedure in combination with the box-counting analysis to classify the alpha ganglion cells in the rat retinae based on the dendritic branching pattern and to investigate morphological changes with retinal eccentricity. The cells could be divided into two groups: cells with simple dendritic pattern (box dimension lower than 1.390) and cells with complex dendritic pattern (box dimension higher than 1.390) according to their dendritic branching pattern complexity. Both were further divided into two subtypes due to the stratification within the inner plexiform layer. In the present study we have shown that the alpha rat RCGs can be classified further by their dendritic branching complexity and thus extend those of previous reports that fractal analysis can be successfully used in neuronal classification, particularly that the fractal dimension represents a robust and sensitive tool for the classification of retinal ganglion cells. A hypothesis of possible functional significance of our classification scheme is also discussed. Copyright © 2011 Elsevier B.V. All rights reserved.

Denervation does not alter the number of neuronal bungarotoxin binding sites on autonomic neurons in the frog cardiac ganglion.

PubMed

Sargent, P B; Bryan, G K; Streichert, L C; Garrett, E N

1991-11-01

The binding of neuronal bungarotoxin (n-BuTX; also known as bungarotoxin 3.1, kappa-bungarotoxin, and toxin F) was analyzed in normal and denervated parasympathetic cardiac ganglia of the frog Rana pipiens, n-BuTX blocks both EPSPs and ACh potentials at 5-20 nM, as determined by intracellular recording techniques. Scatchard analysis on homogenates indicates that cardiac ganglia have two classes of binding sites for 125I-n-BuTX: a high-affinity site with an apparent dissociation constant (Kd,app) of 1.7 nM and a Bmax (number of binding sites) of 3.8 fmol/ganglion and a low-affinity site with a Kd,app of 12 microM and a Bmax of 14 pmol/ganglion. alpha-Bungarotoxin does not appear to interfere with the binding of 125I-n-BuTX to either site. The high-affinity binding site is likely to be the functional nicotinic ACh receptor (AChR), given the similarity between its affinity for 125I-n-BuTX and the concentration of n-BuTX required to block AChR function. Light microscopic autoradiographic analysis of 125I-n-BuTX binding to the ganglion cell surface reveals that toxin binding is concentrated at synaptic sites, which were identified using a synaptic vesicle-specific antibody. Scatchard analysis of autoradiographic data reveals that 125I-n-BuTX binding to the neuronal surface is saturable and has a Kd,app similar to that of the high-affinity binding site characterized in homogenates. Surface binding of 125I-n-BuTX is blocked by nicotine, carbachol, and d-tubocurarine (IC50 less than 20 microM), but not by atropine (IC50 greater than 10 mM). Denervation of the heart increases the ACh sensitivity of cardiac ganglion cells but has no effect upon the number of high-affinity binding sites for 125I-n-BuTX in tissue homogenates. Moreover, autoradiographic analysis indicates that denervation does not alter the number of 125I-n-BuTX binding sites on the ganglion cell surface. n-BuTX is as effective in reducing ganglion cell responses to ACh in denervated ganglia as it is in

Engraftment and Differentiation of Embryonic Stem Cell–Derived Neural Progenitor Cells in the Cochlear Nerve Trunk: Growth of Processes into the Organ of Corti

PubMed Central

Corrales, C. Eduardo; Pan, Luying; Li, Huawei; Liberman, M. Charles; Heller, Stefan; Edge, Albert S.B.

2007-01-01

Hearing loss in mammals is irreversible because cochlear neurons and hair cells do not regenerate. To determine whether we could replace neurons lost to primary neuronal degeneration, we injected EYFP-expressing embryonic stem cell–derived mouse neural progenitor cells into the cochlear nerve trunk in immunosuppressed animals 1 week after destroying the cochlear nerve (spiral ganglion) cells while leaving hair cells intact by ouabain application to the round window at the base of the cochlea in gerbils. At 3 days post transplantation, small grafts were seen that expressed endogenous EYFP and could be immunolabeled for neuron-specific markers. Twelve days after transplantation, the grafts had neurons that extended processes from the nerve core toward the denervated organ of Corti. By 64–98 days, the grafts had sent out abundant processes that occupied a significant portion of the space formerly occupied by the cochlear nerve. The neurites grew in fasciculating bundles projecting through Rosenthal’s canal, the former site of spiral ganglion cells, into the osseous spiral lamina and ultimately into the organ of Corti, where they contacted hair cells. Neuronal counts showed a significant increase in neuronal processes near the sensory epithelium, compared to animals that were denervated without subsequent stem cell transplantation. The regeneration of these neurons shows that neurons differentiated from stem cells have the capacity to grow to a specific target in an animal model of neuronal degeneration. PMID:17013931

Nitrergic nerves derived from the pterygopalatine ganglion innervate arteries irrigating the cerebrum but not the cerebellum and brain stem in monkeys.

PubMed

Ayajiki, Kazuhide; Kobuchi, Shuhei; Tawa, Masashi; Okamura, Tomio

2012-01-01

The functional roles of the nitrergic nerves innervating the monkey cerebral artery were evaluated in a tension-response study examining isolated arteries in vitro and cerebral angiography in vivo. Nicotine produced relaxation of arteries by stimulation of nerve terminals innervating isolated monkey arteries irrigating the cerebrum, cerebellum and brain stem. Relaxation of arteries induced by nicotine was abolished by treatment with N(G)-nitro-L-arginine, a nitric oxide synthase inhibitor, and was restored by addition of L-arginine. Cerebral angiography showed that electrical stimulation of the unilateral greater petrosal nerve, which connects to the pterygopalatine ganglion via the parasympathetic ganglion synapse, produced vasodilatation of the anterior, middle and posterior cerebral arteries in the stimulated side. However, stimulation failed to produce vasodilatation of the superior and anterior-inferior cerebellar arteries and the basilar artery in anesthetized monkeys. Therefore, nitrergic nerves derived from the pterygopalatine ganglion appear to regulate cerebral vasomotor function. In contrast, circulation in the cerebellum and brain stem might be regulated by nitrergic nerves originating not from the pterygopalatine ganglion, but rather from an unknown ganglion (or ganglia).

[Embryonic stem cells and therapeutic cloning].

PubMed

Sunde, A; Eftedal, I

2001-08-30

Increased interest in the therapeutic use of human stem cells has emerged following significant progress in ongoing research. The cloning of a sheep, the isolation of human embryonic stem cells, and the discovery that adult stem cells may be reprogrammed taken together give substance to hopes that novel principles of treatment may be developed for a variety of serious conditions. Embryonic stem cells are derived from pre-embryos at the blastocyst stage and may give rise to all bodily tissues and cells. Animal models have demonstrated that embryonic stem cells when transplanted into adult hosts may differentiate and develop into cells and tissues applicable for treatment of a variety of conditions, including Parkinson's disease, multiple sclerosis, spinal injuries, cardiac stroke and cancer. Transplanted embryonic stem cells are exposed to immune reactions similar to those acting on organ transplants, hence immunosuppression of the recipient is generally required. It is, however, possible to obtain embryonic stem cells that are genetically identical to the patient's own cells by means of therapeutic cloning techniques. The nucleus from a somatic cell is transferred into an egg after removal of the egg's own genetic material. Under specific condition the egg will use genetic information from the somatic cell in organising the formation of a blastocyst which in turn generates embryonic stem cells. These cells have a genetic composition identical to that of the patient and are suitable for stem cell therapy.

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation.

PubMed

Dawes, P M; Vizi, E S

1973-06-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation.2. In the presence of physostigmine, the resting release of acetylcholine was 0.13 +/- 0.01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3.1 +/- 0.4 (pmol/g)/volley in 4 experiments (means +/- S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0.3 Hz.3. Tetrodotoxin, 0.8 muM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5 degrees C reduced to below detectable levels both the resting release and that produced by nerve stimulation.4. The resting release of acetylcholine was increased by a potassium-rich (49.4 mM K(+)) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li(+)).5. (-)-Noradrenaline bitartrate, 3 muM, and (+/-)-adrenaline bitartrate, 1.5 muM, reduced by 70% the output of acetylcholine induced by stimulation at 0.3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine.6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release.

Pituitary adenylate cyclase-activating polypeptide type 1 (PAC1) receptor is expressed during embryonic development of the earthworm.

PubMed

Boros, Akos; Somogyi, Ildikó; Engelmann, Péter; Lubics, Andrea; Reglodi, Dóra; Pollák, Edit; Molnár, László

2010-03-01

Pituitary adenylate cyclase activating polypeptide (PACAP)-like molecules have been shown to be present in cocoon albumin and in Eisenia fetida embryos at an early developmental stage (E1) by immunocytochemistry and radioimmunoassay. Here, we focus on detecting the stage at which PAC1 receptor (PAC1R)-like immunoreactivity first appears in germinal layers and structures, e.g., various parts of the central nervous system (CNS), in developing earthworm embryos. PAC1R-like immunoreactivity was revealed by Western blot and Far Western blot as early as the E2 developmental stage, occurring in the ectoderm and later in specific neurons of the developing CNS. Labeled CNS neurons were first seen in the supraesophageal ganglion (brain) and subsequently in the subesophageal and ventral nerve cord ganglia. Ultrastructurally, PAC1Rs were located mainly on plasma membranes and intracellular membranes, especially on cisternae of the endoplasmic reticulum. Therefore, PACAP-like compounds probably influence the differentiation of germinal layers (at least the ectoderm) and of some neurons and might act as signaling molecules during earthworm embryonic development.

Effects of nitroglycerin and nitroprusside on vascular capacitance of anesthetized ganglion-blocked dogs.

PubMed

Ogilvie, R I; Zborowska-Sluis, D

1991-10-01

To determine whether changes in vascular capacitance induced by nitroglycerin (NTG) and nitroprusside were due to changes in compliance or unstressed vascular volume, doses producing similar reductions in arterial pressure (Psa) were studied on separate days in six dogs anesthetized and ventilated with pentobarbital after splenectomy during ganglion blockade with hexamethonium. Mean circulatory filling pressure (Pmcf) was determined during transient circulatory arrest induced by acetylcholine at baseline blood volumes and after increases of 5 and 10 ml/kg. Central blood volumes (CBVs, pulmonary artery to aortic root) were determined from transit times, and separately measured cardiac output (CO) was estimated by thermodilution (right atrium to pulmonary artery). NTG and nitroprusside produced similar reductions in Psa and Pmcf without significantly altering right atrial pressure (Pra), pressure gradient for venous return, or CO. Total vascular compliance was not altered, but total vascular capacitance was increased on an average of 4.0 +/- 1.4 ml/kg after NTG and 3.0 +/- 1.3 ml/kg after nitroprusside by increases in unstressed volume. Both drugs caused a variable reduction in CBV, averaging 2 ml/kg. Thus, both drugs produced a large increase in peripheral venous capacitance by increasing unstressed vascular volume without altering total vascular compliance.

Effects of cholinergic drugs on receptive field properties of rabbit retinal ganglion cells

PubMed Central

Ariel, M.; Daw, N. W.

1982-01-01

1. Retinal ganglion cells were recorded extracellularly from the rabbit's eye in situ to study the effects of cholinergic drugs on receptive field properties. Physostigmine, an acetylcholinesterase inhibitor, and nicotine increased the spontaneous activity of nearly all retinal ganglion cell types. The effectiveness of physostigmine was roughly correlated with the neurone's inherent level of spontaneous activity. Brisk cells, having high rates of spontaneous firing, showed large increases in their maintained discharge, whereas sluggish cells, with few or no spontaneous spikes, showed small and sometimes transient increases in spontaneous activity during physostigmine. 2. The sensitivity of ganglion cells to spots of optimal size and position did not change substantially during the infusion of physostigmine. However, the responsiveness to light (number of spikes per stimulus above the spontaneous level) increased. This effect occurred with sluggish and more complex cells, rarely with brisk cells. 3. Another effect of physostigmine on sluggish and more complex cells was to make these cells `on—off'. The additional response to the inappropriate change in contrast had a long latency and lacked an initial transient burst. 4. Complex receptive field properties such as orientation sensitivity, radial grating inhibition, speed tuning and size specificity were also examined. These inhibitory properties were still present during infusion of physostigmine and, in most cases, the trigger feature of each cell type remained. 5. These results are consistent with pharmacological results on ACh release from the retina. There appear to be two types of release of ACh, having their most powerful influences on separate classes of cells. One release (transient), occurs at light onset and offset and acts primarily on sluggish and more complex ganglion cells; the other release (tonic) is not light-modulated and acts primarily on brisk cells. A wiring diagram for the ACh cells is

Brief Embryonic Strychnine Exposure in Zebrafish Causes Long-Term Adult Behavioral Impairment with Indications of Embryonic Synaptic Changes

PubMed Central

Roy, Nicole M.; Arpie, Brianna; Lugo, Joseph; Linney, Elwood; Levin, Edward D.; Cerutti, Daniel

2015-01-01

Zebrafish provide a powerful model of the impacts of embryonic toxicant exposure on neural development that may result in long-term behavioral dysfunction. In this study, zebrafish embryos were treated with 1.5 mM strychnine for short embryonic time windows to induce transient changes in inhibitory neural signaling, and were subsequently raised in untreated water until adulthood. PCR analysis showed indications that strychnine exposure altered expression of some genes related to glycinergic, GABAergic and glutamatergic neuronal synapses during embryonic development. In adulthood, treated fish showed significant changes in swimming speed and tank diving behavior compared to controls. Taken together, these data show that a short embryonic exposure to a neurotoxicant can alter development of neural synapses and lead to changes in adult behavior. PMID:23022260

Combination of quercetin, cinnamaldehyde and hirudin protects rat dorsal root ganglion neurons against high glucose-induced injury through Nrf-2/HO-1 activation and NF-κB inhibition.

PubMed

Shi, Yue; Liang, Xiao-Chun; Zhang, Hong; Sun, Qing; Wu, Qun-Li; Qu, Ling

2017-09-01

To examine the effects of the combination of quercetin (Q), cinnamaldehyde (C) and hirudin (H), a Chinese medicine formula on high glucose (HG)-induced apoptosis of cultured dorsal root ganglion (DRG) neurons. DRG neurons exposed to HG (45 mmol/L) for 24 h were employed as an in vitro model of diabetic neuropathy. Cell viability, reactive oxygen species (ROS) level and apoptosis were determined. The expression of nuclear factor of Kappa B (NF-κB), inhibitory kappa Bα(IκBα), phosphorylated IκBα and Nf-E2 related factor 2 (Nrf2) were examined using reverse transcription-polymerase chain reaction (RT-PCR) and Western blot assay. The expression of hemeoxygenase-1 (HO-1), interleukin-6 (IL-6), tumor necrosis factor (TNF-α) and caspase-3 were also examined by RT-PCR and Western blot assay. HG treatment markedly increased DRG neuron apoptosis via increasing intracellular ROS level and activating the NF-κB signaling pathway (P<0.05). Co-treatment with Q, C, H and their combination decreased HG-induced caspase-3 activation and apoptosis (P<0.05 or P<0.01). The expressions of NF-κB, IL-6 and TNF-α were down-regulated, and Nrf2/HO-1 expression was up-regulated (P<0.05 or P<0.01). QCH has better effect in scavenging ROS, activating Nrf-2/HO-1, and down-regulating the NF-κB pathway than other treatment group. DRG neurons' apoptosis was increased in diabetic conditions, which was reduced by QCH formula treatment. The possible reason could be activating Nrf-2/HO-1 pathway, scavenging ROS, and inhibition of NF-κB activation. The effect of QCH combination was better than each monomer or the combination of the two monomers.

Distinguishing ischaemic optic neuropathy from optic neuritis by ganglion cell analysis.

PubMed

Erlich-Malona, Natalie; Mendoza-Santiesteban, Carlos E; Hedges, Thomas R; Patel, Nimesh; Monaco, Caitlin; Cole, Emily

2016-12-01

To determine whether a pattern of altitudinal ganglion cell loss, as detected and measured by optical coherence tomography (OCT), can be used to distinguish non-arteritic ischaemic optic neuropathy (NAION) from optic neuritis (ON) during the acute phase, and whether the rate or severity of ganglion cell loss differs between the two diseases. We performed a retrospective, case-control study of 44 patients (50 eyes) with ON or NAION and 44 age-matched controls. Non-arteritic ischaemic optic neuropathy and ON patients had OCT at presentation and four consecutive follow-up visits. Controls had OCT at one point in time. The ganglion cell complex (GCC) was evaluated in the macula, and the retinal nerve fibre layer (RNFL) was evaluated in the peripapillary region. Ganglion cell complex thickness, RNFL thickness and GCC mean superior and inferior hemispheric difference were compared between NAION and ON patients at each time-point using unpaired t-tests and between disease and control subjects at first measurement using paired t-tests. Mean time from onset of symptoms to initial presentation was 10.7 ± 6.6 days in NAION and 11.7 ± 8.6 days in ON (p = 0.67). There was a significantly greater vertical hemispheric difference in GCC thickness in NAION patients than ON patients at all time-points (5.5-10.7 μm versus 3.1-3.6 μm, p = 0.01-0.049). Mean GCC thickness was significantly decreased at less than 2 weeks after onset in NAION compared to age-matched controls (72.1 μm versus 82.1 μm, p < 0.001), as well as in ON compared to age-matched controls (74.3 μm versus 84.5 μm, p < 0.001). Progression and severity of GCC and RNFL loss did not differ significantly between NAION and ON. A quantitative comparison of mean superior and inferior hemispheric GCC thickness with OCT may be used to distinguish NAION from ON. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Reactive oxygen species alters the electrophysiological properties and raises [Ca2+]i in intracardiac ganglion neurons

PubMed Central

Dyavanapalli, Jhansi; Rimmer, Katrina

2010-01-01

We have investigated the effects of the reactive oxygen species (ROS) donors hydrogen peroxide (H2O2) and tert-butyl hydroperoxide (t-BHP) on the intrinsic electrophysiological characteristics: ganglionic transmission and resting [Ca2+]i in neonate and adult rat intracardiac ganglion (ICG) neurons. Intracellular recordings were made using sharp microelectrodes filled with either 0.5 M KCl or Oregon Green 488 BAPTA-1, allowing recording of electrical properties and measurement of [Ca2+]i. H2O2 and t-BHP both hyperpolarized the resting membrane potential and reduced membrane resistance. In adult ICG neurons, the hyperpolarizing action of H2O2 was reversed fully by Ba2+ and partially by tetraethylammonium, muscarine, and linopirdine. H2O2 and t-BHP reduced the action potential afterhyperpolarization (AHP) amplitude but had no impact on either overshoot or AHP duration. ROS donors evoked an increase in discharge adaptation to long depolarizing current pulses. H2O2 blocked ganglionic transmission in most ICG neurons but did not alter nicotine-evoked depolarizations. By contrast, t-BHP had no significant action on ganglionic transmission. H2O2 and t-BHP increased resting intracellular Ca2+ levels to 1.6 ( ± 0.6, n = 11, P < 0.01) and 1.6 ( ± 0.3, n = 8, P < 0.001), respectively, of control value (1.0, ∼60 nM). The ROS scavenger catalase prevented the actions of H2O2, and this protection extended beyond the period of application. Superoxide dismutase partially shielded against the action of H2O2, but this was limited to the period of application. These data demonstrate that ROS decreases the excitability and ganglionic transmission of ICG neurons, attenuating parasympathetic control of the heart. PMID:20445155

Long term exposure to cell phone frequencies (900 and 1800 MHz) induces apoptosis, mitochondrial oxidative stress and TRPV1 channel activation in the hippocampus and dorsal root ganglion of rats.

PubMed

Ertilav, Kemal; Uslusoy, Fuat; Ataizi, Serdar; Nazıroğlu, Mustafa

2018-06-01

Mobile phone providers use electromagnetic radiation (EMR) with frequencies ranging from 900 to 1800 MHz. The increasing use of mobile phones has been accompanied by several potentially pathological consequences, such as neurological diseases related to hippocampal (HIPPON) and dorsal root ganglion neuron (DRGN). The TRPV1 channel is activated different stimuli, including CapN, high temperature and oxidative stress. We investigated the contribution TRPV1 to mitochondrial oxidative stress and apoptosis in HIPPON and DRGN following long term exposure to 900 and 1800 MHz in a rat model. Twenty-four adult rats were equally divided into the following groups: (1) control, (2) 900 MHz, and (3) 1800 MHz exposure. Each experimental group was exposed to EMR for 60 min/ 5 days of the week during the one year. The 900 and 1800 MHz EMR exposure induced increases in TRPV1 currents, intracellular free calcium influx (Ca 2+ ), reactive oxygen species (ROS) production, mitochondrial membrane depolarization (JC-1), apoptosis, and caspase 3 and 9 activities in the HIPPON and DRGN. These deleterious processes were further increased in the 1800 MHz experimental group compared to the 900 MHz exposure group. In conclusion, mitochondrial oxidative stress, programmed cell death and Ca 2+ entry pathway through TRPV1 activation in the HIPPON and DRGN of rats were increased in the rat model following exposure to 900 and 1800 MHz cell frequencies. Our results suggest that exposure to 900 and 1800 MHz EMR may induce a dose-associated, TRPV1-mediated stress response.

Ganglion Cell Loss and Age-Related Visual Loss: A Cortical Pooling Analysis

PubMed Central

SCHMIDT, LAURA A.; LY-SCHROEDER, EMILY; SWANSON, WILLIAM H.

2006-01-01

Purpose To evaluate the ability of the cortical pooling model to predict the effects of random, mild ganglion cell loss, we compared the predictions of the model with the age-related loss and variability in achromatic and chromatic contrast sensitivity. Methods The relative sensitivity to small (0.5°) and large (3.0°) stimuli was compared in older (mean = 67 years, n = 27) and younger (mean = 23 years, n = 32) adults. Contrast sensitivity for modulations along the luminance, equiluminant L-cone, and equiluminant S-cone axes was assessed at the fovea and at four peripheral locations (12°). Results When the stimuli were large, threshold measurements obtained from all participants were reliable and well within the range of modulations along the chromatic axes that could be produced by the phosphors of the CRT. For the large stimuli, neither long- nor short-term variability increased as a function of age. Increasing the size of the stimulus did not decrease the magnitude of the age-related losses when the stimulus was chromatic, and visual losses observed with large chromatic stimuli were not different from those obtained with small achromatic stimuli. Moreover, chromatic contrast sensitivity assessments identified significant visual losses in four individuals who were not identified by achromatic contrast sensitivity assessments and only missed identifying one individual with significant losses in achromatic contrast sensitivity. Conclusions The declines in achromatic and chromatic sensitivity as a function of age (0.4 – 0.7 dB per decade) were similar to those obtained in previous studies of achromatic and chromatic perimetry and are consistent with the loss of retinal ganglion cells reported in histologic studies. The results of this study are consistent with the predictions the cortical pooling model makes for both variability and contrast sensitivity. These findings emphasize that selective visual impairments do not necessarily reflect preferential damage to

Hypoxia delays hematopoiesis: retention of embryonic hemoglobin and erythrocytes in larval rainbow trout, Oncorhynchus mykiss, during chronic hypoxia exposure.

PubMed

Bianchini, Kristin; Wright, Patricia A

2013-12-01

In rainbow trout development, a switch occurs from high-affinity embryonic hemoglobin (Hb) and round, embryonic erythrocytes to lower-affinity adult Hb and oval, adult erythrocytes. Our study investigated the early ontogeny of rainbow trout blood properties and the hypoxia response. We hypothesized that hypoxia exposure would delay the ontogenetic turnover of Hb and erythrocytes because retention of high-affinity embryonic Hb would facilitate oxygen loading. To test this hypothesis we developed a method of efficiently extracting blood from individual embryos and larvae and optimized several techniques for measuring hematological parameters on microliter (0.5-2.0 μl) blood samples. In chronic hypoxia (30% of oxygen saturation), stage-matched embryos and larvae possessed half the Hb concentration, erythrocyte counts and hematocrit observed in normoxia. Hypoxia-reared larvae also had threefold to sixfold higher mRNA expression of the embryonic Hb α-1, β-1 and β-2 subunits relative to stage-matched normoxia-reared larvae. Furthermore, in hypoxia, the round embryonic erythrocytic shape persisted into later developmental stages. Despite these differences, Hb-oxygen affinity (P50), cooperativity and the Root effect were unaltered in hypoxia-reared O. mykiss. The data support our hypothesis that chronic hypoxia delays the ontogenetic turnover of Hb and erythrocytes, but without the predicted functional consequences (i.e. higher than expected P50). These results also suggest that the Hb-oxygen affinity is protected during development in chronic hypoxia to favor oxygen unloading at the tissues. We conclude that in early trout development, the blood-oxygen transport system responds very differently to chronic hypoxia relative to adults, possibly because respiration depends relatively more on oxygen diffusion than convection.

Increased Hyperalgesia and Proinflammatory Cytokines in the Spinal Cord and Dorsal Root Ganglion After Surgery and/or Fentanyl Administration in Rats

PubMed Central

Chang, Lu; Ye, Fang; Luo, Quehua; Tao, Yuanxiang

2018-01-01

BACKGROUND: Perioperative fentanyl has been reported to induce hyperalgesia and increase postoperative pain. In this study, we tried to investigate behavioral hyperalgesia, the expression of proinflammatory cytokines, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and the activation of microglia in the spinal cord and dorsal root ganglion (DRG) in a rat model of surgical plantar incision with or without perioperative fentanyl. METHODS: Four groups of rats (n = 32 for each group) were subcutaneously injected with fentanyl at 60 μg/kg or normal saline for 4 times with 15-minute intervals. Plantar incisions were made to rats in 2 groups after the second drug injection. Mechanical and thermal nociceptive thresholds were assessed by the tail pressure test and paw withdrawal test on the day before, at 1, 2, 3, 4 hours, and on the days 1–7 after drug injection. The lumbar spinal cord, bilateral DRG, and cerebrospinal fluid of 4 rats in each group were collected to measure IL-1β, IL-6, and TNF-α on the day before, at the fourth hour, and on the days 1, 3, 5, and 7 after drug injection. The lumbar spinal cord and bilateral DRG were removed to detect the ionized calcium-binding adapter molecule 1 on the day before and on the days 1 and 7 after drug injection. RESULTS: Rats injected with normal saline only demonstrated no significant mechanical or thermal hyperalgesia or any increases of IL-1β, IL-6, and TNF-α in the spinal cord or DRG. However, injection of fentanyl induced analgesia within as early as 4 hours and a significant delayed tail mechanical and bilateral plantar thermal hyperalgesia after injections lasting for 2 days, while surgical plantar incision induced a significant mechanical and thermal hyperalgesia lasting for 1–4 days. The combination of fentanyl and incision further aggravated the hyperalgesia and prolonged the duration of hyperalgesia. The fentanyl or surgical incision upregulated the expression

Increased Hyperalgesia and Proinflammatory Cytokines in the Spinal Cord and Dorsal Root Ganglion After Surgery and/or Fentanyl Administration in Rats.

PubMed

Chang, Lu; Ye, Fang; Luo, Quehua; Tao, Yuanxiang; Shu, Haihua

2018-01-01

Perioperative fentanyl has been reported to induce hyperalgesia and increase postoperative pain. In this study, we tried to investigate behavioral hyperalgesia, the expression of proinflammatory cytokines, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), and the activation of microglia in the spinal cord and dorsal root ganglion (DRG) in a rat model of surgical plantar incision with or without perioperative fentanyl. Four groups of rats (n = 32 for each group) were subcutaneously injected with fentanyl at 60 μg/kg or normal saline for 4 times with 15-minute intervals. Plantar incisions were made to rats in 2 groups after the second drug injection. Mechanical and thermal nociceptive thresholds were assessed by the tail pressure test and paw withdrawal test on the day before, at 1, 2, 3, 4 hours, and on the days 1-7 after drug injection. The lumbar spinal cord, bilateral DRG, and cerebrospinal fluid of 4 rats in each group were collected to measure IL-1β, IL-6, and TNF-α on the day before, at the fourth hour, and on the days 1, 3, 5, and 7 after drug injection. The lumbar spinal cord and bilateral DRG were removed to detect the ionized calcium-binding adapter molecule 1 on the day before and on the days 1 and 7 after drug injection. Rats injected with normal saline only demonstrated no significant mechanical or thermal hyperalgesia or any increases of IL-1β, IL-6, and TNF-α in the spinal cord or DRG. However, injection of fentanyl induced analgesia within as early as 4 hours and a significant delayed tail mechanical and bilateral plantar thermal hyperalgesia after injections lasting for 2 days, while surgical plantar incision induced a significant mechanical and thermal hyperalgesia lasting for 1-4 days. The combination of fentanyl and incision further aggravated the hyperalgesia and prolonged the duration of hyperalgesia. The fentanyl or surgical incision upregulated the expression of IL-1β, IL-6, and TNF-α in the

Spatial segregation of adaptation and predictive sensitization in retinal ganglion cells

PubMed Central

Kastner, David B.; Baccus, Stephen A.

2014-01-01

Sensory systems change their sensitivity based upon recent stimuli to adjust their response range to the range of inputs, and to predict future sensory input. Here we report the presence of retinal ganglion cells that have antagonistic plasticity, showing central adaptation and peripheral sensitization. Ganglion cell responses were captured by a spatiotemporal model with independently adapting excitatory and inhibitory subunits, and sensitization requires GABAergic inhibition. Using a simple theory of signal detection we show that the sensitizing surround conforms to an optimal inference model that continually updates the prior signal probability. This indicates that small receptive field regions have dual functionality—to adapt to the local range of signals, but sensitize based upon the probability of the presence of that signal. Within this framework, we show that sensitization predicts the location of a nearby object, revealing prediction as a new functional role for adapting inhibition in the nervous system. PMID:23932000

Signaling via the transcriptionally regulated activin receptor 2B is a novel mediator of neuronal cell death during chicken ciliary ganglion development.

PubMed

Koszinowski, S; Buss, K; Kaehlcke, K; Krieglstein, K

2015-04-01

The TGF-β ligand superfamily members activin A and BMP control important aspects of embryonic neuronal development and differentiation. Both are known to bind to activin receptor subtypes IIA (ActRIIA) and IIB, while in the avian ciliary ganglion (CG), so far only ActRIIA-expression has been described. We show that the expression of ACVR2B, coding for the ActRIIB, is tightly regulated during CG development and the knockdown of ACVR2B expression leads to a deregulation in the execution of neuronal apoptosis and therefore affects ontogenetic programmed cell death in vivo. While the differentiation of choroid neurons was impeded in the knockdown, pointing toward a reduction in activin A-mediated neural differentiation signaling, naturally occurring neuronal cell death in the CG was not prevented by follistatin treatment. Systemic injections of the BMP antagonist noggin, on the other hand, reduced the number of apoptotic neurons to a similar extent as ACVR2B knockdown. We therefore propose a novel pathway in the regulation of CG neuron ontogenetic programmed cell death, which could be mediated by BMP and signals via the ActRIIB. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Four alpha ganglion cell types in mouse retina: Function, structure, and molecular signatures

PubMed Central

Sanes, Joshua R.

2017-01-01

The retina communicates with the brain using ≥30 parallel channels, each carried by axons of distinct types of retinal ganglion cells. In every mammalian retina one finds so-called "alpha" ganglion cells (αRGCs), identified by their large cell bodies, stout axons, wide and mono-stratified dendritic fields, and high levels of neurofilament protein. In the mouse, three αRGC types have been described based on responses to light steps: On-sustained, Off-sustained, and Off-transient. Here we employed a transgenic mouse line that labels αRGCs in the live retina, allowing systematic targeted recordings. We characterize the three known types and identify a fourth, with On-transient responses. All four αRGC types share basic aspects of visual signaling, including a large receptive field center, a weak antagonistic surround, and absence of any direction selectivity. They also share a distinctive waveform of the action potential, faster than that of other RGC types. Morphologically, they differ in the level of dendritic stratification within the IPL, which accounts for their response properties. Molecularly, each type has a distinct signature. A comparison across mammals suggests a common theme, in which four large-bodied ganglion cell types split the visual signal into four channels arranged symmetrically with respect to polarity and kinetics. PMID:28753612

Strychnine, but not PMBA, inhibits neuronal nicotinic acetylcholine receptors expressed by rabbit retinal ganglion cells.

PubMed

Renna, J M; Strang, C E; Amthor, F R; Keyser, K T

2007-01-01

Strychnine is considered a selective competitive antagonist of glycine gated Cl- channels (Saitoh et al., 1994) and studies have used strychnine at low micromolar concentrations to study the role of glycine in rabbit retina (Linn, 1998; Protti et al., 2005). However, other studies have shown that strychnine, in the concentrations commonly used, is also a potent competitive antagonist of alpha7 nicotinic acetylcholine receptors (nAChRs; Matsubayashi et al., 1998). We tested the effects of low micromolar concentrations of strychnine and 3-[2'-phosphonomethyl[1,1'-biphenyl]-3-yl] alanine (PMBA), a specific glycine receptor blocker (Saitoh et al., 1994; Hosie et al., 1999) on the activation of both alpha7 nAChRs on retinal ganglion cells and on ganglion cell responses to a light flash. Extracellular recordings were obtained from ganglion cells in an isolated retina/choroid preparation and 500 microM choline was used as an alpha7 agonist (Alkondon et al., 1997). We recorded from brisk sustained and brisk transient OFF cells, many of which have been previously shown to have alpha7 receptors (Strang et al., 2005). Further, we tested the effect of strychnine, PMBA and alpha-bungarotoxin on the binding of tetramethylrhodamine alpha-bungarotoxin in the inner plexiform layer. Our data indicates that strychnine, at doses as low as 1.0 microM, can inhibit the alpha7 nAChR-mediated response to choline, but PMBA at concentrations as high as 0.4 microM does not. Binding studies show strychnine and alpha-bungarotoxin inhibit binding of labeled alpha-bungarotoxin in the IPL. Thus, the effects of strychnine application may be to inhibit glycine receptors expressed by ganglion cell or to inhibit amacrine cell alpha7 nAChRs, both of which would result in an increase in the ganglion cell responses. Further research will be required to disentangle the effects of strychnine previously believed to be caused by a single mechanism of glycine receptor inhibition.

Brief embryonic strychnine exposure in zebrafish causes long-term adult behavioral impairment with indications of embryonic synaptic changes.

PubMed

Roy, Nicole M; Arpie, Brianna; Lugo, Joseph; Linney, Elwood; Levin, Edward D; Cerutti, Daniel

2012-01-01

Zebrafish provide a powerful model of the impacts of embryonic toxicant exposure on neural development that may result in long-term behavioral dysfunction. In this study, zebrafish embryos were treated with 1.5mM strychnine for short embryonic time windows to induce transient changes in inhibitory neural signaling, and were subsequently raised in untreated water until adulthood. PCR analysis showed indications that strychnine exposure altered expression of some genes related to glycinergic, GABAergic and glutamatergic neuronal synapses during embryonic development. In adulthood, treated fish showed significant changes in swimming speed and tank diving behavior compared to controls. Taken together, these data show that a short embryonic exposure to a neurotoxicant can alter development of neural synapses and lead to changes in adult behavior. Copyright © 2012 Elsevier Inc. All rights reserved.

Nervus terminalis ganglion of the bonnethead shark (Sphyrna tiburo): evidence for cholinergic and catecholaminergic influence on two cell types distinguished by peptide immunocytochemistry.

PubMed

White, J; Meredith, M

1995-01-16

The nervus terminalis is a ganglionated vertebrate cranial nerve of unknown function that connects the brain and the peripheral nasal structures. To investigate its function, we have studied nervus terminalis ganglion morphology and physiology in the bonnethead shark (Sphyrna tiburo), where the nerve is particularly prominent. Immunocytochemistry for gonadotropin-releasing hormone (GnRH) and Leu-Pro-Leu-Arg-Phe-NH2 (LPLRFamide) revealed two distinct populations of cells. Both were acetylcholinesterase positive, but LPLR-Famide-immunoreactive cells consistently stained more darkly for acetylcholinesterase activity. Tyrosine hydroxylase immunocytochemistry revealed fibers and terminal-like puncta in the ganglion, primarily in areas containing GnRH-immunoreactive cells. Consistent with the anatomy, in vitro electrophysiological recordings provided evidence for cholinergic and catecholaminergic actions. In extracellular recordings, acetylcholine had a variable effect on baseline ganglion cell activity, whereas norepinephrine consistently reduced activity. Electrical stimulation of the nerve trunks suppressed ganglion activity, as did impulses from the brain in vivo. During electrical suppression, acetylcholine consistently increased activity, and norepinephrine decreased activity. Muscarinic and, to a lesser extent, alpha-adrenergic antagonists both increased activity during the electrical suppression, suggesting involvement of both systems. Intracellular recordings revealed two types of ganglion cells that were distinguishable pharmacologically and physiologically. Some cells were hyperpolarized by cholinergic agonists and unaffected by norepinephrine; these cells did not depolarize with peripheral nerve trunk stimulation. Another group of cells did depolarize with peripheral trunk stimulation; a representative of this group was depolarized by carbachol and hyperpolarized by norepinephrine. These and other data suggest that the bonnethead nervus terminalis ganglion

Effect of Tissue Heterogeneity on the Transmembrane Potential of Type-1 Spiral Ganglion Neurons: A Simulation Study.

PubMed

Sriperumbudur, Kiran Kumar; Pau, Hans Wilhelm; van Rienen, Ursula

2018-03-01

Electric stimulation of the auditory nerve by cochlear implants has been a successful clinical intervention to treat the sensory neural deafness. In this pathological condition of the cochlea, type-1 spiral ganglion neurons in Rosenthal's canal play a vital role in the action potential initiation. Various morphological studies of the human temporal bones suggest that the spiral ganglion neurons are surrounded by heterogeneous structures formed by a variety of cells and tissues. However, the existing simulation models have not considered the tissue heterogeneity in the Rosenthal's canal while studying the electric field interaction with spiral ganglion neurons. Unlike the existing models, we have implemented the tissue heterogeneity in the Rosenthal's canal using a computationally inexpensive image based method in a two-dimensional finite element model. Our simulation results suggest that the spatial heterogeneity of surrounding tissues influences the electric field distribution in the Rosenthal's canal, and thereby alters the transmembrane potential of the spiral ganglion neurons. In addition to the academic interest, these results are especially useful to understand how the latest tissue regeneration methods such as gene therapy and drug-induced resprouting of peripheral axons, which probably modify the density of the tissues in the Rosenthal's canal, affect the cochlear implant functionality.

The Effect of Transcutaneous Electrical Nerve Stimulation of Sympathetic Ganglions and Acupuncture Points on Distal Blood Flow.

PubMed

Kamali, Fahimeh; Mirkhani, Hossein; Nematollahi, Ahmadreza; Heidari, Saeed; Moosavi, Elahesadat; Mohamadi, Marzieh

2017-04-01

Transcutaneous electrical nerve stimulation (TENS) is a widely-practiced method to increase blood flow in clinical practice. The best location for stimulation to achieve optimal blood flow has not yet been determined. We compared the effect of TENS application at sympathetic ganglions and acupuncture points on blood flow in the foot of healthy individuals. Seventy-five healthy individuals were randomly assigned to three groups. The first group received cutaneous electrical stimulation at the thoracolumbar sympathetic ganglions. The second group received stimulation at acupuncture points. The third group received stimulation in the mid-calf area as a control group. Blood flow was recorded at time zero as baseline and every 3 minutes after baseline during stimulation, with a laser Doppler flow-meter. Individuals who received sympathetic ganglion stimulation showed significantly greater blood flow than those receiving acupuncture point stimulation or those in the control group (p<0.001). Data analysis revealed that blood flow at different times during stimulation increased significantly from time zero in each group. Therefore, the application of low-frequency TENS at the thoracolumbar sympathetic ganglions was more effective in increasing peripheral blood circulation than stimulation at acupuncture points. Copyright © 2017 Medical Association of Pharmacopuncture Institute. Published by Elsevier B.V. All rights reserved.

Acetylcholine release from the rabbit isolated superior cervical ganglion preparation

PubMed Central

Dawes, P. M.; Vizi, E. S.

1973-01-01

1. The rabbit isolated superior cervical ganglion preparation has been used to measure the release of acetylcholine from the tissue at rest and during preganglionic nerve stimulation. 2. In the presence of physostigmine, the resting release of acetylcholine was 0·13 ± 0·01 (nmol/g)/min (10 experiments) and that during stimulation with 300 shocks at 10 Hz was 3·1 ± 0·4 (pmol/g)/volley in 4 experiments (means ± S.E.M.). The volley output was independent of the frequency of stimulation over the range 1 to 10 Hz but was higher at 0·3 Hz. 3. Tetrodotoxin, 0·8 μM, had no effect on the resting release of acetylcholine but reduced the stimulated release below detectable levels (2 pmol). Lowering the temperature of the bathing fluid to 5° C reduced to below detectable levels both the resting release and that produced by nerve stimulation. 4. The resting release of acetylcholine was increased by a potassium-rich (49·4 mM K+) bathing solution and by replacing the sodium chloride in the solution with lithium chloride (113 mM Li+). 5. (-)-Noradrenaline bitartrate, 3 μM, and (±)-adrenaline bitartrate, 1·5 μM, reduced by 70% the output of acetylcholine induced by stimulation at 0·3 Hz, but failed to reduce the resting release or that evoked by stimulation at 10 Hz. The inhibition was reversed by phentolamine. 6. It is concluded that the rabbit superior cervical ganglion in vitro is a suitable preparation for studying transmitter release and that the ganglion blocking effect of catecholamines is due to a reduction in transmitter release. PMID:4733726

Vesicular glutamate transporters, VGluT1 and VGluT2, in the trigeminal ganglion neurons of the rat, with special reference to coexpression.

PubMed

Li, Jin-Lian; Xiong, Kang-Hui; Dong, Yu-Lin; Fujiyama, Fumino; Kaneko, Takeshi; Mizuno, Noboru

2003-08-18

Vesicular glutamate transporters are responsible for glutamate transport into synaptic vesicles. In the present study, we examined immunohistochemically the expression of vesicular glutamate transporters, VGluT1 and VGluT2, in trigeminal ganglion neurons of the rat. Immunohistochemistry for VGluT1 and VGluT2 indicated that more than 80% of trigeminal ganglion neurons express VGluT1 and/or VGluT2 in their cell bodies. It also indicated that large and small trigeminal ganglion neurons express VGluT2 more frequently than VGluT1. Dual immunofluorescence histochemistry for VGluT1 and VGluT2 indicated that trigeminal ganglion neurons express VGluT2 more frequently than VGluT1 and that more than 80% of VGluT-expressing trigeminal ganglion neurons express VGluT1 and VGluT2. Many axon terminals in the superficial layers of the medullary dorsal horn also showed VGluT1 and VGluT2 immunoreactivities. Some of these axon terminals were confirmed to form the central core of the synaptic glomerulus. These results indicated that VGluT1 and VGluT2 are coexpressed in the cell bodies and axon terminals in most trigeminal ganglion neurons. Copyright 2003 Wiley-Liss, Inc.

Retinal ganglion cells in diabetes

PubMed Central

Kern, Timothy S; Barber, Alistair J

2008-01-01

Diabetic retinopathy has long been recognized as a vascular disease that develops in most patients, and it was believed that the visual dysfunction that develops in some diabetics was due to the vascular lesions used to characterize the disease. It is becoming increasingly clear that neuronal cells of the retina also are affected by diabetes, resulting in dysfunction and even degeneration of some neuronal cells. Retinal ganglion cells (RGCs) are the best studied of the retinal neurons with respect to the effect of diabetes. Although investigations are providing new information about RGCs in diabetes, including therapies to inhibit the neurodegeneration, critical information about the function, anatomy and response properties of these cells is yet needed to understand the relationship between RGC changes and visual dysfunction in diabetes. PMID:18565995

Progranulin deficiency causes the retinal ganglion cell loss during development.

PubMed

Kuse, Yoshiki; Tsuruma, Kazuhiro; Mizoguchi, Takahiro; Shimazawa, Masamitsu; Hara, Hideaki

2017-05-10

Astrocytes are glial cells that support and protect neurons in the central nervous systems including the retina. Retinal ganglion cells (RGCs) are in contact with the astrocytes and our earlier findings showed the reduction of the number of cells in the ganglion cell layer in adult progranulin deficient mice. In the present study, we focused on the time of activation of the astrocytes and the alterations in the number of RGCs in the retina and optic nerve in progranulin deficient mice. Our findings showed that the number of Brn3a-positive cells was reduced and the expression of glial fibrillary acidic protein (GFAP) was increased in progranulin deficient mice. The progranulin deficient mice had a high expression of GFAP on postnatal day 9 (P9) but not on postnatal day 1. These mice also had a decrease in the number of the Brn3a-positive cells on P9. Taken together, these findings indicate that the absence of progranulin can affect the survival of RGCs subsequent the activation of astrocytes during retinal development.

Enhanced Stem Cell Differentiation and Immunopurification of Genome Engineered Human Retinal Ganglion Cells.

PubMed

Sluch, Valentin M; Chamling, Xitiz; Liu, Melissa M; Berlinicke, Cynthia A; Cheng, Jie; Mitchell, Katherine L; Welsbie, Derek S; Zack, Donald J

2017-11-01

Human pluripotent stem cells have the potential to promote biological studies and accelerate drug discovery efforts by making possible direct experimentation on a variety of human cell types of interest. However, stem cell cultures are generally heterogeneous and efficient differentiation and purification protocols are often lacking. Here, we describe the generation of clustered regularly-interspaced short palindromic repeats(CRISPR)-Cas9 engineered reporter knock-in embryonic stem cell lines in which tdTomato and a unique cell-surface protein, THY1.2, are expressed under the control of the retinal ganglion cell (RGC)-enriched gene BRN3B. Using these reporter cell lines, we greatly improved adherent stem cell differentiation to the RGC lineage by optimizing a novel combination of small molecules and established an anti-THY1.2-based protocol that allows for large-scale RGC immunopurification. RNA-sequencing confirmed the similarity of the stem cell-derived RGCs to their endogenous human counterparts. Additionally, we developed an in vitro axonal injury model suitable for studying signaling pathways and mechanisms of human RGC cell death and for high-throughput screening for neuroprotective compounds. Using this system in combination with RNAi-based knockdown, we show that knockdown of dual leucine kinase (DLK) promotes survival of human RGCs, expanding to the human system prior reports that DLK inhibition is neuroprotective for murine RGCs. These improvements will facilitate the development and use of large-scale experimental paradigms that require numbers of pure RGCs that were not previously obtainable. Stem Cells Translational Medicine 2017;6:1972-1986. © 2017 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

Spontaneous cell death in the semilunar ganglion during fetal and postnatal life in the ox, sheep, goat and guinea pig.

PubMed

Bortolami, R; Lucchi, M L; Callegari, E; De Pasquale, V; Lalatta Costerbosa, G

1979-07-15

A massive cell loss occurs in the semilunar ganglion. It is the result of either a casting-off of the semilunar ganglion cells into the cavernous sinus or a transformation of several cells into polyhedral cells with an epithelial-like organization, a process which immediately precedes their further degeneration.

Eliminating Glutamatergic Input onto Horizontal Cells Changes the Dynamic Range and Receptive Field Organization of Mouse Retinal Ganglion Cells.

PubMed

Ströh, Sebastian; Puller, Christian; Swirski, Sebastian; Hölzel, Maj-Britt; van der Linde, Lea I S; Segelken, Jasmin; Schultz, Konrad; Block, Christoph; Monyer, Hannah; Willecke, Klaus; Weiler, Reto; Greschner, Martin; Janssen-Bienhold, Ulrike; Dedek, Karin

2018-02-21

In the mammalian retina, horizontal cells receive glutamatergic inputs from many rod and cone photoreceptors and return feedback signals to them, thereby changing photoreceptor glutamate release in a light-dependent manner. Horizontal cells also provide feedforward signals to bipolar cells. It is unclear, however, how horizontal cell signals also affect the temporal, spatial, and contrast tuning in retinal output neurons, the ganglion cells. To study this, we generated a genetically modified mouse line in which we eliminated the light dependency of feedback by deleting glutamate receptors from mouse horizontal cells. This genetic modification allowed us to investigate the impact of horizontal cells on ganglion cell signaling independent of the actual mode of feedback in the outer retina and without pharmacological manipulation of signal transmission. In control and genetically modified mice (both sexes), we recorded the light responses of transient OFF-α retinal ganglion cells in the intact retina. Excitatory postsynaptic currents (EPSCs) were reduced and the cells were tuned to lower temporal frequencies and higher contrasts, presumably because photoreceptor output was attenuated. Moreover, receptive fields of recorded cells showed a significantly altered surround structure. Our data thus suggest that horizontal cells are responsible for adjusting the dynamic range of retinal ganglion cells and, together with amacrine cells, contribute to the center/surround organization of ganglion cell receptive fields in the mouse. SIGNIFICANCE STATEMENT Horizontal cells represent a major neuronal class in the mammalian retina and provide lateral feedback and feedforward signals to photoreceptors and bipolar cells, respectively. The mode of signal transmission remains controversial and, moreover, the contribution of horizontal cells to visual processing is still elusive. To address the question of how horizontal cells affect retinal output signals, we recorded the light

Diagnostic accuracy of ganglion cell complex substructures in different stages of primary open-angle glaucoma.

PubMed

Elbendary, Amal M; Abd El-Latef, Mohamed Hafez; Elsorogy, Hisham I; Enaam, Kamal M

2017-08-01

To evaluate diagnostic accuracy of substructure of ganglion cell complex versus peripapillary nerve fiber layer (NFL) thickness using spectral domain optical coherence tomography (SD-OCT) in different stages of glaucoma. Thirty eyes were normal, 120 were glaucomatous. Glaucomatous eyes were classified into: early glaucoma (46), moderate glaucoma (48), and severe glaucoma (26). Perimetry and SD-OCT were done. Peripapillary NFL thickness, ganglion cell layer (GCL), macular NFL thickness, combined GCL and macular ganglion cell complex (GCC), were recorded. Area under receiver operating characteristic curves (AUCs) was used to verify performance of different OCT parameters. Peripapillary NFL, GCL, and GCC thickness values were significantly different in all stages of glaucoma. All comparisons were significantly different; normal versus early, early versus moderate and moderate versus severe. The best parameters that distinguished normal from early stage were: peripapillary NFL (AUC: 0.90), GCC (AUC: 0.75), early from moderate stage were: peripapillary NFL thickness (AUC: 0.85), GCL (0.81),GCC (0.81), moderate from severe stage were: GCC (AUC:0.95), macular NFL (AUC:0.91), GCL (AUC:0.89), and peripapillary NFL (AUC:0.88). Peripapllary NFL and GCC thinning showed paradoxical course. The most diagnosed parameter in early glaucoma was peripapillary NFL and in severe glaucoma was GCC. In severe glaucoma, macular NFL showed higher diagnostic power than GCL and peripapillary NFL. Ganglion cell complex mapping may provide good alternative to optic disc imaging in advanced glaucoma with poor fixation. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

Outcomes of Open Dorsal Wrist Ganglion Excision in Active-Duty Military Personnel.

PubMed

Balazs, George C; Donohue, Michael A; Drake, Matthew L; Ipsen, Derek; Nanos, George P; Tintle, Scott M

2015-09-01

To examine the most common presenting complaints of active-duty service members with isolated dorsal wrist ganglions and to determine the rate of return to unrestricted duty after open excision. Surgical records at 2 military facilities were screened to identify male and female active duty service members undergoing isolated open excision of dorsal wrist ganglions from January 1, 2006 to January 1, 2014. Electronic medical records and service disability databases were searched to identify the most common presenting symptoms and to determine whether patients returned to unrestricted active duty after surgery. Postoperative outcomes examined were pain persisting greater than 4 weeks after surgery, stiffness requiring formal occupational therapy treatment, surgical wound complications, and recurrence. A total of 125 active duty military personnel (Army, 54; Navy, 43; and Marine Corps, 28) met criteria for inclusion. Mean follow-up was 45 months. Fifteen percent (8 of 54) of the Army personnel were given permanent waivers from performing push-ups owing to persistent pain and stiffness. Pain persisting greater than 4 weeks after surgery was an independent predictor of eventual need for a permanent push-up waiver. The overall recurrence incidence was 9%. No demographic or perioperative factors were associated with recurrence. Patients whose occupation or activities require forceful wrist extension should be counseled on the considerable risk of residual pain and functional limitations that may occur after open dorsal wrist ganglion excision. Therapeutic IV. Published by Elsevier Inc.

Functional expression of ionotropic glutamate receptors in the rabbit retinal ganglion cells.

PubMed

Chen, Yin-Peng; Chiao, Chuan-Chin

2012-01-03

It has been known that retinal ganglion cells (RGCs) with distinct morphologies have different physiological properties. It was hypothesized that different functions of RGCs may in part result from various expressions of N-methyl-d-aspartate (NMDA), α-amino-3-hydroxyl-5-methyl-isoxazole-4-propinoic acid (AMPA), and kainic acid (KA) receptors on their dendrites. In the present study, we aimed to characterize the functional expression of AMPA and NMDA receptors of morphologically identified RGCs in the wholemount rabbit retina. The agmatine (AGB) activation assay was used to reveal functional expression of ionotropic glutamate receptors after the RGCs were targeted by injecting Neurobiotin. To examine the excitability of these glutamate receptors in an agonist specific manner, the lower concentrations of AMPA (2 μM) and NMDA (100 μM) were chosen to examine G7 (ON-OFF direction selective ganglion cells) and G11 (alpha ganglion cells) types of RGCs. We found that less than 40% of G7 type RGCs had salient AGB activation when incubated with 2 μM AMPA or 100 μM NMDA. The G11 type RGCs also showed similar activation frequencies, except that all of the OFF subtype examined had no AGB permeation under the same AMPA concentration. These results suggest that RGCs with large somata (G7 and G11 types) may express various heterogeneous functional ionotropic glutamate receptors, thus in part rendering their functional diversity. Copyright © 2011 Elsevier B.V. All rights reserved.

Atlantoaxial Joint Distraction with a New Expandable Device for the Treatment of Basilar Invagination with Preservation of the C2 Nerve Root: A Cadaveric Anatomical Study.

PubMed

Polli, Filippo Maria; Trungu, Sokol; Miscusi, Massimo; Forcato, Stefano; Visocchi, Massimiliano; Raco, Antonino

2017-01-01

Atlantoaxial joint distraction has been advocated for the decompression of the brain stem in patients affected by basilar invagination, avoiding direct transoral decompression. This technique requires C2 ganglion resection and it is often impossible to perform due to the peculiar bony anatomy. We describe a cadaveric anatomical study supporting the feasibility of C1-C2 distraction performed with an expandable device, allowing easier insertion of the tool and preservation of the C2 nerve root. In five adult cadaveric specimens, posterior atlantoaxial surgical exposure was performed and an expandable system was inserted within the C1-C2 joint. The expansion of the device, leading to active distraction of the joint space, together with all the surgical steps of the technique was recorded with anatomical pictures and the final results were checked with a computed tomography (CT) scan. Insertion of the device was easily performed in all cases without anatomical conflict with the C2 ganglion; CT scans confirmed the distraction of the C1-C2 joint. This cadaveric anatomical study confirms the feasibility of the introduction of an expandable and flexible device within the C1-C2 joint, allowing it's distraction and preservation of the C2 ganglion.

Nanosecond laser pulse stimulation of spiral ganglion neurons and model cells.

PubMed

Rettenmaier, Alexander; Lenarz, Thomas; Reuter, Günter

2014-04-01

Optical stimulation of the inner ear has recently attracted attention, suggesting a higher frequency resolution compared to electrical cochlear implants due to its high spatial stimulation selectivity. Although the feasibility of the effect is shown in multiple in vivo experiments, the stimulation mechanism remains open to discussion. Here we investigate in single-cell measurements the reaction of spiral ganglion neurons and model cells to irradiation with a nanosecond-pulsed laser beam over a broad wavelength range from 420 nm up to 1950 nm using the patch clamp technique. Cell reactions were wavelength- and pulse-energy-dependent but too small to elicit action potentials in the investigated spiral ganglion neurons. As the applied radiant exposure was much higher than the reported threshold for in vivo experiments in the same laser regime, we conclude that in a stimulation paradigm with nanosecond-pulses, direct neuronal stimulation is not the main cause of optical cochlea stimulation.

Sciatica and claudication caused by ganglion cyst.

PubMed

Yang, Guang; Wen, Xiaoyu; Gong, Yubao; Yang, Chen

2013-12-15

Case report. We report a rare case that a ganglion cyst compressed the sciatic nerve and caused sciatica and claudication in a 51-year-old male. Sciatica and claudication commonly occurs in spinal stenosis. To our knowledge, only 4 cases have been reported on sciatica resulting from posterior ganglion cyst of hip. A 51-year-old male had a 2-month history of radiating pain on his right leg. He could only walk 20 to 30 m before stopping and standing to rest for 1 to 3 minutes. Interestingly, he was able to walk longer distances (about 200 m) when walking slowly in small steps, without any rest. He had been treated as a case of lumbar disc herniation, but conservative treatment was ineffective. On buttock examination, a round, hard, and fixative mass was palpated at the exit of the sciatic nerve. MR imaging of hip revealed a multilocular cystic mass located on the posterior aspect of the superior gemellus and obturator internus, compressing the sciatic nerve. On operation, we found that the cyst extended to the superior gemellus and the obturator internus, positioned right at the outlet of the sciatic nerve. At 18 months of follow-up, the patient continued to be symptom free. He returned to comprehensive physical activity with no limitations. For an extraspinal source, a direct compression on the sciatic nerve also resulted in sciatica and claudication. A meticulous physical examination is very important for the differential diagnosis of extraspinal sciatica from spinal sciatica.

Drug discovery for hearing loss: Phenotypic screening of chemical compounds on primary cultures of the spiral ganglion.

PubMed

Whitlon, Donna S

2017-06-01

In the United States there are, at present, no drugs that are specifically FDA approved to treat hearing loss. Although several clinical trials are ongoing, including one testing D-methionine that is supported by the US Army, none of these trials directly address the effect of noise exposure on cochlear spiral ganglion neurons. We recently published the first report of a systematic chemical compound screen using primary, mammalian spiral ganglion cultures in which we were able to detect a compound and others in its class that increased neurite elongation, a critical step in restoring cochlear synapses after noise induced hearing loss. Here we discuss the issues, both pro and con, that influenced the development of our approach. These considerations may be useful for future compound screens that target the same or other attributes of cochlear spiral ganglion neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

Morphological relationship between the superior cervical ganglion and cervical nerves in Japanese cadaver donors.

PubMed

Mitsuoka, Kazuyuki; Kikutani, Takeshi; Sato, Iwao

2017-02-01

There are various communications between the superior cervical ganglion (SCG) and the vagus and glossopharyngeal nerves. However, little information exists concerning the origin of these sympathetic ganglion branches at the superior, middle, and inferior regions of the human SCG. The aim of this study was to describe the human SCG in a morphometric manner with the communication with cranial and cervical nerves and supply. This study characterized 72 SCG samples from 54 elderly Japanese human cadavers (30 males, 24 females; 65-100 years old). The SCG size (length, width, and thickness) and location were measured from the jugular foramen. We also defined the communication branches of the SCG to the vagus, glossopharyngeal, cervical, and accessory nerves at three regions (superior, middle, and inferior regions) of the SCG. Finally, we examined the arrangement and origin of the branch communications in detail and confirmed our observations, using histological sections of the SCG. The SCG in all cadaver donors was detected at the C2 and C3 vertebra levels. The number of SCG branches supplied the communicating branches, such as the carotid branch, communicating branch of the vagus nerve, and glossopharyngeal nerve, were frequently detected in the superior region of the SCG (χ 2  = 587.72, df = 26, p  <   .001). The number of ganglion cells with a large number of neurons per unit area (1 mm 2 ) was most often found in the middle region with shrunken neurons of the SCG compared with other regions. The communication branches of the SCG are mainly connected to the vagus and glossopharyngeal nerves. Characterizing these branches can provide useful data for head and neck ganglion block and surgical treatments.

[Sphenopalatine ganglion pulsed radiofrequency treatment in patients suffering from chronic face and head pain].

PubMed

Akbas, Mert; Gunduz, Emel; Sanli, Suat; Yegin, Arif

2016-01-01

There are various facial pain syndromes including trigeminal neuralgia, trigeminal neuropathic pain and atypical facial pain syndromes. Effectiveness of the pulsed radiofrequency in managing various pain syndromes has been clearly demonstrated. There are a limited number of studies on the pulsed radiofrequency treatment for sphenopalatine ganglion in patients suffering from face and head pain. The purpose of this study is to evaluate the satisfaction of pulsed radiofrequency treatment at our patients retrospectively. Infrazygomatic approach was used for the pulsed radiofrequency of the sphenopalatine ganglion under fluoroscopic guidance. After the tip of the needle reached the target point, 0.25-0.5ms pulse width was applied for sensory stimulation at frequencies from 50Hz to 1V. Paraesthesias were exposed at the roof of the nose at 0.5-0.7V. To rule out trigeminal contact that led to rhythmic mandibular contraction, motor stimulation at a frequency of 2Hz was applied. Then, four cycles of pulsed radiofrequency lesioning were performed for 120s at a temperature of 42°C. Pain relief could not be achieved in 23% of the patients (unacceptable), whereas pain was completely relieved in 35% of the patients (excellent) and mild to moderate pain relief could be achieved in 42% of the patients (good) through sphenopalatine ganglion-pulsed radiofrequency treatment. Pulsed radiofrequency of the sphenopalatine ganglion is effective in treating the patients suffering from intractable chronic facial and head pain as shown by our findings. There is a need for prospective, randomized, controlled trials in order to confirm the efficacy and safety of this new treatment modality in chronic head and face pain. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Sphenopalatine ganglion pulsed radiofrequency treatment in patients suffering from chronic face and head pain.

PubMed

Akbas, Mert; Gunduz, Emel; Sanli, Suat; Yegin, Arif

2016-01-01

There are various facial pain syndromes including trigeminal neuralgia, trigeminal neuropathic pain and atypical facial pain syndromes. Effectiveness of the pulsed radiofrequency in managing various pain syndromes has been clearly demonstrated. There are a limited number of studies on the pulsed radiofrequency treatment for sphenopalatine ganglion in patients suffering from face and head pain. The purpose of this study is to evaluate the satisfaction of pulsed radiofrequency treatment at our patients retrospectively. Infrazygomatic approach was used for the pulsed radiofrequency of the sphenopalatine ganglion under fluoroscopic guidance. After the tip of the needle reached the target point, 0.25-0.5 ms pulse width was applied for sensory stimulation at frequencies from 50 Hz to 1 V. Paraesthesias were exposed at the roof of the nose at 0.5-0.7 V. To rule out trigeminal contact that led to rhythmic mandibular contraction, motor stimulation at a frequency of 2 Hz was applied. Then, four cycles of pulsed radiofrequency lesioning were performed for 120 s at a temperature of 42°C. Pain relief could not be achieved in 23% of the patients (unacceptable), whereas pain was completely relieved in 35% of the patients (excellent) and mild to moderate pain relief could be achieved in 42% of the patients (good) through sphenopalatine ganglion-pulsed radiofrequency treatment. Pulsed radiofrequency of the sphenopalatine ganglion is effective in treating the patients suffering from intractable chronic facial and head pain as shown by our findings. There is a need for prospective, randomized, controlled trials in order to confirm the efficacy and safety of this new treatment modality in chronic head and face pain. Copyright © 2014 Sociedade Brasileira de Anestesiologia. Published by Elsevier Editora Ltda. All rights reserved.

The release of acetylcholine from post-ganglionic cell bodies in response to depolarization.

PubMed Central

Johnson, D A; Pilar, G

1980-01-01

1. Acetylcholine (Ach) release from parasympathetic ganglia cell somata was investigated in denervated avian ciliary ganglia. Three days after the input to the ganglion (the oculomotor nerve) was sectioned, all presynaptic nerve terminals had degenerated. 2. Denervated ganglia were shown to contain endogenous ACh and to be capable of synthesizing [3H]ACh from [3H]choline added to the incubation medium. 3. In response to depolarization induced by incubation in 50 mM-[K+]o, denervated ganglia released [3H]ACh into bath effluents in amounts approximately 15% of the non-denervated contralateral control. This release was shown to be Ca2+ dependent in both intact and denervated ganglia. 4. Antidromic electrical stimulation of ciliary nerves also elicited [3H]ACh release. Nicotine (1 microgram/microliter.) depolarized denervated ciliary ganglion cells and evoked release of the transmitter and this release was antagonized by curare. 5. It is concluded that the ganglionic cell bodies sysnthesized ACh and released the transmitter in response to K+ depolarization, antidromic stimulation and cholinergic agonists, despite the lack of morphological specializations usually associated with stimulus-induced release of neurotransmitter. The evidence suggests the existence of a mechanism of transmitter release which is Ca2+ dependent, probably from a cytoplasmic pool and therefore distinct from the usual vesicular release at the nerve terminal. Images Plate 1 Plate 2 PMID:6247485

Ouabain-Induced Apoptosis in Cochlear Hair Cells and Spiral Ganglion Neurons In Vitro

PubMed Central

Fu, Yong; Ding, Dalian; Jiang, Haiyan; Salvi, Richard

2013-01-01

Ouabain is a common tool to explore the pathophysiological changes in adult mammalian cochlea in vivo. In prior studies, locally administering ouabain via round window membrane demonstrated that the ototoxic effects of ouabain in vivo varied among mammalian species. Little is known about the ototoxic effects in vitro. Thus, we prepared cochlear organotypic cultures from postnatal day-3 rats and treated these cultures with ouabain at 50, 500, and 1000 μM for different time to elucidate the ototoxic effects of ouabain in vitro and to provide insights that could explain the comparative ototoxic effects of ouabain in vivo. Degeneration of cochlear hair cells and spiral ganglion neurons was evaluated by hair-cell staining and neurofilament labeling, respectively. Annexin V staining was used to detect apoptotic cells. A quantitative RT-PCR apoptosis-focused gene array determined changes in apoptosis-related genes. The results showed that ouabain-induced damage in vitro was dose and time dependent. 500 μM ouabain and 1000 μM ouabain were destructively traumatic to both spiral ganglion neurons and cochlear hair cells in an apoptotic signal-dependent pathway. The major apoptotic pathways in ouabain-induced spiral ganglion neuron apoptosis culminated in the stimulation of the p53 pathway and triggering of apoptosis by a network of proapoptotic signaling pathways. PMID:24228256

[Ropivacaine use in transnasal sphenopalatine ganglion block for post dural puncture headache in obstetric patients - case series].

PubMed

Furtado, Inês; Lima, Isabel Flor de; Pedro, Sérgio

2018-02-02

Sphenopalatine ganglion block is widely accepted in chronic pain; however it has been underestimated in post dural puncture headache treatment. The ganglion block does not restore normal cerebrospinal fluid dynamics but effectively reduces symptoms associated with resultant hypotension. When correctly applied it may avoid performance of epidural blood patch. The transnasal approach is a simple and minimally invasive technique. In the cases presented, we attempted to perform and report the ganglion block effectiveness and duration, using ropivacaine. We present four obstetrics patients with post dural puncture headache, after epidural or combined techniques, with Tuohy needle 18G that underwent a safe and successful Sphenopalatine ganglion block. We performed the block 24-48h after dural puncture, with 4mL of ropivacaine 0.75% in each nostril. In three cases pain recurred within 12-48h, although less intense. In one patient a second block was performed with complete relief and without further recurrence. In the other two patients a blood patch was performed without success. All patients were asymptomatic within 7 days. The average duration of analgesic effect of the block remains poorly defined. In the cases reported, blocking with ropivacaine was a simple, safe and effective technique, with immediate and sustained pain relief for at least 12-24h. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Electrical Interaction of Paired Ganglion Cells in the Leech

PubMed Central

Eckert, Roger

1963-01-01

The two paired giant ganglion cells (PGC's) found in each ganglion of the leech central nervous system fire synchronously in response to certain sensory input. Polarizing current passed into either of these cells is seen to displace the membrane potentials of both cells, the voltage attenuation between the two somata ranging from 2 to 5 times. This attenuation factor remains unchanged when the direction of the polarizing current is reversed, and remains about the same when the other cell of the pair is directly polarized. When one of the PGC's is partially depolarized with outward current, a repetitive train of impulses is generated. Each spike is followed by a spike in the other cell. Occasionally, a small subspike potential is seen in place of a follower spike. This potential appears to differ in shape and time course from synaptic potentials elicited by afferent input to these cells, and appears rather to be an electrotonic potential derived from the prejunctional impulse in the stimulated PGC. It is proposed that transmission between these cells is electrical, being accomplished by a flow of local circuit current across a non-rectifying junction or connection to the spike-initiating region of the other PGC. PMID:19873553

The trophic effect of ouabain on retinal ganglion cells is mediated by IL-1β and TNF-α

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salles von-Held-Ventura, Juliana; Mázala-de-Oliveira, Thalita; Cândida da Rocha Oliveira, Amanda

Ouabain is a steroid hormone that binds to the enzyme Na{sup +}, K{sup +} – ATPase and stimulates different intracellular pathways controlling growth, proliferation and cell survival. IL-1β and TNF-α are pleiotropic molecules, conventionally regarded as pro-inflammatory cytokines with well-known effects in the immune system. In addition, IL-1β and TNF-α also play important roles in the nervous system including neuroprotective effects. Previous data from our group showed that ouabain treatment is able to induce an increase in retinal ganglion cell survival kept in mixed retinal cell cultures. The aim of this work was to investigate if IL-1β and TNF-α couldmore » be mediating the trophic effect of ouabain on retinal ganglion cells. Our results show that the trophic effect of ouabain on retinal ganglion cell was inhibited by either anti-IL-1β or anti-TNF-α antibodies. In agreement, IL-1β or TNF-α increased the retinal ganglion cells survival in a dose-dependent manner. Accordingly, ouabain treatment induces a temporal release of TNF-α and IL-1β from retinal cell cultures. Interestingly, TNF-α and IL-1β regulate each other intracellular levels. Our results suggest that ouabain treatment triggers the activation of TNF-α and IL-1β signaling pathways leading to an increase in retinal ganglion cell survival. - Highlights: • Pro-inflammatory cytokines regulates the ouabain effect on RGC survival. • Ouabain treatment modulates the intracellular levels of TNF-α and IL-1β. • Ouabain induces the release of TNF-α and IL-1β in retinal cell cultures.« less

Somatic Donor Cell Type Correlates with Embryonic, but Not Extra-Embryonic, Gene Expression in Postimplantation Cloned Embryos

PubMed Central

Inoue, Kimiko; Ogura, Atsuo

2013-01-01

The great majority of embryos generated by somatic cell nuclear transfer (SCNT) display defined abnormal phenotypes after implantation, such as an increased likelihood of death and abnormal placentation. To gain better insight into the underlying mechanisms, we analyzed genome-wide gene expression profiles of day 6.5 postimplantation mouse embryos cloned from three different cell types (cumulus cells, neonatal Sertoli cells and fibroblasts). The embryos retrieved from the uteri were separated into embryonic (epiblast) and extraembryonic (extraembryonic ectoderm and ectoplacental cone) tissues and were subjected to gene microarray analysis. Genotype- and sex-matched embryos produced by in vitro fertilization were used as controls. Principal component analysis revealed that whereas the gene expression patterns in the embryonic tissues varied according to the donor cell type, those in extraembryonic tissues were relatively consistent across all groups. Within each group, the embryonic tissues had more differentially expressed genes (DEGs) (>2-fold vs. controls) than did the extraembryonic tissues (P<1.0×10–26). In the embryonic tissues, one of the common abnormalities was upregulation of Dlk1, a paternally imprinted gene. This might be a potential cause of the occasional placenta-only conceptuses seen in SCNT-generated mouse embryos (1–5% per embryos transferred in our laboratory), because dysregulation of the same gene is known to cause developmental failure of embryos derived from induced pluripotent stem cells. There were also some DEGs in the extraembryonic tissues, which might explain the poor development of SCNT-derived placentas at early stages. These findings suggest that SCNT affects the embryonic and extraembryonic development differentially and might cause further deterioration in the embryonic lineage in a donor cell-specific manner. This could explain donor cell-dependent variations in cloning efficiency using SCNT. PMID:24146866

Activation of TRPM2 and TRPV1 Channels in Dorsal Root Ganglion by NADPH Oxidase and Protein Kinase C Molecular Pathways: a Patch Clamp Study.

PubMed

Nazıroğlu, Mustafa

2017-03-01

Despite considerable research, the mechanisms of neuropathic pain induced by excessive oxidative stress production and overload calcium ion (Ca 2+ ) entry in dorsal root ganglion (DRG) remain substantially unidentified. The transient receptor potential melastatin 2 (TRPM2) and vanilloid 1 (TRPV1) channels are activated with different stimuli including oxidative stress. TRPM2 and TRPV1 have been shown to be involved in induction of neuropathic pain. However, the activation mechanisms of TRPM2 and TRPV1 via NADPH oxidase and protein kinase C (PKC) pathways are poorly understood. In this study, I investigated the roles of NADPH oxidase and PKC on Ca 2+ entry through TRPM2 and TRPV1 channels in in vitro DRG neurons of rats. Rat DRG neurons were used in whole-cell patch clamp experiments. The H 2 O 2 -induced TRPM2 current densities were decreased by N-(p-amylcinnamoyl)anthranilic acid (ACA), and dose-dependent capsaicin (CAP) and H 2 O 2 -induced TRPV1 currents were inhibited by capsazepine (CPZ). The TRPV1 channel is activated in the DRG neurons by 0.01 mM capsaicin but not 0.001 mM or 0.05 mM capsaicin. TRPM2 and TRPV1 currents were increased by the PKC activator, phorbol myristate acetate (PMA), although the currents were decreased by ACA, CPZ, and the PKC inhibitor, bisindolylmaleimide I (BIM). Both channel currents were further increased by PMA + H 2 O 2 as compared to H 2 O 2 only. In the combined presence of PMA + BIM, no TRPM2 or TRPV1 currents were observed. The CAP and H 2 O 2 -induced TRPM2 current densities were also decreased by the NADPH oxidase inhibitors apocynin and N-Acetylcysteine. In conclusion, these results demonstrate a protective role for NADPH oxidase and PKC inhibitors on Ca 2+ entry through TRPM2 and TRPV1 channels in DRG neurons. Since excessive oxidative stress production and Ca 2+ entry are implicated in the pathophysiology of neuropathic pain, the findings may be relevant to the etiology and treatment of neuropathology in DRG neurons.

Upregulation of N-type calcium channels in the soma of uninjured dorsal root ganglion neurons contributes to neuropathic pain by increasing neuronal excitability following peripheral nerve injury.

PubMed

Yang, Jie; Xie, Man-Xiu; Hu, Li; Wang, Xiao-Fang; Mai, Jie-Zhen; Li, Yong-Yong; Wu, Ning; Zhang, Cheng; Li, Jin; Pang, Rui-Ping; Liu, Xian-Guo

2018-07-01

N-type voltage-gated calcium (Cav2.2) channels are expressed in the central terminals of dorsal root ganglion (DRG) neurons, and are critical for neurotransmitter release. Cav2.2 channels are also expressed in the soma of DRG neurons, where their function remains largely unknown. Here, we showed that Cav2.2 was upregulated in the soma of uninjured L4 DRG neurons, but downregulated in those of injured L5 DRG neurons following L5 spinal nerve ligation (L5-SNL). Local application of specific Cav2.2 blockers (ω-conotoxin GVIA, 1-100 μM or ZC88, 10-1000 μM) onto L4 and 6 DRGs on the operated side, but not the contralateral side, dose-dependently reversed mechanical allodynia induced by L5-SNL. Patch clamp recordings revealed that both ω-conotoxin GVIA (1 μM) and ZC88 (10 μM) depressed hyperexcitability in L4 but not in L5 DRG neurons of L5-SNL rats. Consistent with this, knockdown of Cav2.2 in L4 DRG neurons with AAV-Cav2.2 shRNA substantially prevented L5-SNL-induced mechanical allodynia and hyperexcitability of L4 DRG neurons. Furthermore, in L5-SNL rats, interleukin-1 beta (IL-1β) and IL-10 were upregulated in L4 DRGs and L5 DRGs, respectively. Intrathecal injection of IL-1β induced mechanical allodynia and Cav2.2 upregulation in bilateral L4-6 DRGs of naïve rats, whereas injection of IL-10 substantially prevented mechanical allodynia and Cav2.2 upregulation in L4 DRGs in L5-SNL rats. Finally, in cultured DRG neurons, Cav2.2 was dose-dependently upregulated by IL-1β and downregulated by IL-10. These data indicate that the upregulation of Cav2.2 in uninjured DRG neurons via IL-1β over-production contributes to neuropathic pain by increasing neuronal excitability following peripheral nerve injury. Copyright © 2018 Elsevier Inc. All rights reserved.

Gene expression dynamics during embryonic development in rainbow trout

USDA-ARS?s Scientific Manuscript database

The supply of maternal RNAs in fertilized egg and activation of embryonic genome during maternal-zygotic transition (MZT) are important for normal embryonic development. In order to identify genes and gene products that are essential in the regulation of embryonic development in rainbow trout, RNA-S...

Satellite glial cells in the trigeminal ganglion as a determinant of orofacial neuropathic pain

PubMed Central

VIT, JEAN-PHILIPPE; JASMIN, LUC; BHARGAVA, ADITI; OHARA, PETER T.

2008-01-01

Satellite glial cells (SGCs) tightly envelop the perikarya of primary sensory neurons in peripheral ganglion and are identified by their morphology and the presence of proteins not found in ganglion neurons. These SGC-unique proteins include the inwardly rectifying K+ channel Kir4.1, the connexin-43 (Cx43) subunit of gap junctions, the purinergic receptor P2Y4 and soluble guanylate cyclase. We also present evidence that the small-conductance Ca2+-activated K+ channel SK3 is present only in SGCs and that SGCs divide following nerve injury. All the above proteins are involved, either directly or indirectly, in potassium ion (K+) buffering and, thus, can influence the level of neuronal excitability, which, in turn, has been associated with neuropathic pain conditions. We used in vivo RNA interference to reduce the expression of Cx43 (present only in SGCs) in the rat trigeminal ganglion and show that this results in the development of spontaneous pain behavior. The pain behavior is present only when Cx43 is reduced and returns to normal when Cx43 concentrations are restored. This finding shows that perturbation of a single SGC-specific protein is sufficient to induce pain responses and demonstrates the importance of PNS glial cell activity in the pathophysiology of neuropathic pain. PMID:18568096

Localization of laminin B1 mRNA in retinal ganglion cells by in situ hybridization

PubMed Central

1990-01-01

In the nervous system, neuronal migration and axonal growth are dependent on specific interactions with extracellular matrix proteins. During development of the vertebrate retina, ganglion cell axons extend along the internal limiting (basement) membrane and form the optic nerve. Laminin, a major component of basement membranes, is known to be present in the internal limiting membrane, and might be involved in the growth of ganglion cell axons. The identity of the cells that produce retinal laminin, however, has not been established. In the present study, we have used in situ hybridization to localize the sites of laminin B1 mRNA synthesis in the developing mouse retina. Our results show that there are at least two principal sites of laminin B1 mRNA synthesis: (a) the hyaloid vessels and the lens during the period of major axonal outgrowth, and (b) the retinal ganglion cells at later development stages. Muller (glial) cells, the major class of nonneuronal cells in the retina, do not appear to express laminin B1 mRNA either during development or in the adult retina. In Northern blots, we found a single transcript of approximately 6-kb size that encodes the laminin B1 chain in the retina. Moreover, laminin B1 mRNA level was four- to fivefold higher in the postnatal retina compared to that in the adult. Our results show that in addition to nonneuronal cells, retinal ganglion cells also synthesize laminin. The function of laminin in postnatal retinas, however, remains to be elucidated. Nevertheless, our findings raise the possibility that neurons in other parts of the nervous system might also synthesize extracellular matrix proteins. PMID:2351694

Plant hormone cross-talk: the pivot of root growth.

PubMed

Pacifici, Elena; Polverari, Laura; Sabatini, Sabrina

2015-02-01

Root indeterminate growth and its outstanding ability to produce new tissues continuously make this organ a highly dynamic structure able to respond promptly to external environmental stimuli. Developmental processes therefore need to be finely tuned, and hormonal cross-talk plays a pivotal role in the regulation of root growth. In contrast to what happens in animals, plant development is a post-embryonic process. A pool of stem cells, placed in a niche at the apex of the meristem, is a source of self-renewing cells that provides cells for tissue formation. During the first days post-germination, the meristem reaches its final size as a result of a balance between cell division and cell differentiation. A complex network of interactions between hormonal pathways co-ordinates such developmental inputs. In recent years, by means of molecular and computational approaches, many efforts have been made aiming to define the molecular components of these networks. In this review, we focus our attention on the molecular mechanisms at the basis of hormone cross-talk during root meristem size determination. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Lateral root development in the maize (Zea mays) lateral rootless1 mutant

PubMed Central

Husakova, Eva; Hochholdinger, Frank; Soukup, Ales

2013-01-01

Background and Aims The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. Methods Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. Key Results The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1-related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. Conclusions The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no

Lateral root development in the maize (Zea mays) lateral rootless1 mutant.

PubMed

Husakova, Eva; Hochholdinger, Frank; Soukup, Ales

2013-07-01

The maize lrt1 (lateral rootless1) mutant is impaired in its development of lateral roots during early post-embryonic development. The aim of this study was to characterize, in detail, the influences that the mutation exerts on lateral root initiation and the subsequent developments, as well as to describe the behaviour of the entire plant under variable environmental conditions. Mutant lrt1 plants were cultivated under different conditions of hydroponics, and in between sheets of moist paper. Cleared whole mounts and anatomical sections were used in combination with both selected staining procedures and histochemical tests to follow root development. Root surface permeability tests and the biochemical quantification of lignin were performed to complement the structural data. The data presented suggest a redefinition of lrt1 function in lateral roots as a promoter of later development; however, neither the complete absence of lateral roots nor the frequency of their initiation is linked to lrt1 function. The developmental effects of lrt1 are under strong environmental influences. Mutant primordia are affected in structure, growth and emergence; and the majority of primordia terminate their growth during this last step, or shortly thereafter. The lateral roots are impaired in the maintenance of the root apical meristem. The primary root shows disturbances in the organization of both epidermal and subepidermal layers. The lrt1-related cell-wall modifications include: lignification in peripheral layers, the deposition of polyphenolic substances and a higher activity of peroxidase. The present study provides novel insights into the function of the lrt1 gene in root system development. The lrt1 gene participates in the spatial distribution of initiation, but not in its frequency. Later, the development of lateral roots is strongly affected. The effect of the lrt1 mutation is not as obvious in the primary root, with no influences observed on the root apical meristem

Scaffolding for Three-Dimensional Embryonic Vasculogenesis

NASA Astrophysics Data System (ADS)

Kraehenbuehl, Thomas P.; Aday, Sezin; Ferreira, Lino S.

Biomaterial scaffolds have great potential to support efficient vascular differentiation of embryonic stem cells. Vascular cell fate-specific biochemical and biophysical cues have been identified and incorporated into three-dimensional (3D) biomaterials to efficiently direct embryonic vasculogenesis. The resulting vascular-like tissue can be used for regenerative medicine applications, further elucidation of biophysical and biochemical cues governing vasculogenesis, and drug discovery. In this chapter, we give an overview on the following: (1) developmental cues for directed differentiation of human embryonic stem cells (hESCs) into vascular cells, (2) 3D vascular differentiation in embryoid bodies (EBs), (3) preparation of 3D scaffolds for the vascular differentiation of hESCs, and (4) the most significant studies combining scaffolding and hESCs for development of vascular-like tissue.

Chronic hypoxic incubation blunts a cardiovascular reflex loop in embryonic American alligator (Alligator mississippiensis).

PubMed

Eme, John; Hicks, James W; Crossley, Dane A

2011-10-01

Hypoxia is a naturally occurring environmental challenge for embryonic non-avian reptiles, and this study is the first to investigate the impact of chronic hypoxia on a possible chemoreflex loop in a developing non-avian reptile. We measured heart rate and blood pressure in normoxic and hypoxic-incubated (10% O(2)) American alligator embryos (Alligator mississippiensis) at 70 and 90/95% of development. We hypothesized that hypoxic incubation would blunt embryonic alligators' response to a reflex loop stimulated by phenylbiguanide (PBG), a 5-HT(3) receptor agonist that stimulates vagal pulmonary C-fiber afferents. PBG injection caused a hypotensive bradycardia in 70 and 95% of development embryos (paired t tests, P < 0.05), a response similar to mammals breathing inspired air (all injections made through occlusive catheter in tertiary chorioallantoic membrane artery). Hypoxic incubation blunted the bradycardic response to PBG in embryos at 95% of development (two-way ANOVA, P < 0.01). We also demonstrated that the vagally mediated afferent limb of this reflex can be partially or completely blocked in ovo with a 5-HT(3) receptor blockade using ondansetron hydrochloride dihydrate (OHD), with a ganglionic blockade using hexamethonium, or with a cholinergic blockade using atropine. Atropine eliminated the hypotensive and bradycardic responses to PBG, and OHD and hexamethonium significantly blunted these responses. This cardiovascular reflex mediated by the vagus was affected by hypoxic incubation, suggesting that reptilian sympathetic and parasympathetic reflex loops have the potential for developmental plasticity in response to hypoxia. We suggest that the American alligator, with an extended length of time between each developmental stage relative to avian species, may provide an excellent model to test the cardiorespiratory effects of prolonged exposure to changes in atmospheric gases. This extended period allows for lengthy studies at each stage without the

A SNAP-25 cleaving chimera of botulinum neurotoxin /A and /E prevents TNFα-induced elevation of the activities of native TRP channels on early postnatal rat dorsal root ganglion neurons.

PubMed

Nugent, Marc; Yusef, Yamil R; Meng, Jianghui; Wang, Jiafu; Dolly, J Oliver

2018-06-12

Transient receptor potential (TRP) vallinoid 1 (TRPV1) and ankyrin 1 (TRPA1) are two transducing channels expressed on peripheral sensory nerves involved in pain sensation. Upregulation of their expression, stimulated by inflammatory cytokines and growth factors in animal pain models, correlate with the induction of nociceptive hyper-sensitivity. Herein, we firstly demonstrate by immuno-cytochemical labelling that TNFα augments the surface content of these channels on rat cultured dorsal root ganglion (DRG) neurons which, in turn, enhances the electrophysiological and functional responses of the latter to their specific agonists. A molecular basis underlying this TNFα-dependent enhancement was unveiled by pre-treating DRGs with a recently-published chimeric protein, consisting of the protease light chain (LC) of botulinum neurotoxin (BoNT) serotype E fused to full-length BoNT/A (LC/E-BoNT/A). This cleaves synaptosomal-associated protein of Mr 25k (SNAP-25) and reported previously to exhibit anti-nociceptive activity in a rat model of neuropathic pain. Low pM concentrations of this chimera were found to prevent the TNFα-stimulated delivery of TRPV1/A1 to the neuronal plasmalemma and, accordingly, decreased their incremental functional activities relative to those of control cells, an effect accompanied by SNAP-25 cleavage. Advantageously, LC/E-BoNT/A did not reduce the basal surface contents of the two channels or their pharmacological responses. Thus, use of multiple complementary methodologies provides evidence that LC/E-BoNT/A abolishes the TNFα-dependent augmented, but not resting, surface trafficking of TRPV1/A1. As TNFα is known to induce nociceptive hyper-sensitivity in vivo, our observed inhibition by LC/E-BoNT/A of its action in vitro could contribute to its potential alleviation of pain. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

PubMed Central

LaMotte, Robert H.; Chao, MA

2009-01-01

The cell body or soma in the dosal root ganglion (DRG) is normally excitable and this excitability can increase and persist after an injury of peripheral sensory neurons. In a rat model of radicular pain, an intraforaminal implantation of a rod that chronically compressed the lumbar DRG (“CCD” model) resulted in neuronal somal hyperexcitability and spontaneous activity that was accompanied by hyperalgesia in the ipsilateral hind paw. By the 5th day after onset of CCD, there was a novel upregulation in neuronal expression of the chemokine, monocyte chemoattractant protein-1 (MCP-1 or CCL2) and also its receptor, CCR2. The neurons developed, in response to topically applied MCP-1, an excitatory response that they normally do not have. CCD also activated non-neuronal cells including, for example, the endothelial cells as evidenced by angiogenesis in the form of an increased number of capillaries in the DRG after 7 days. A working hypothesis is that the CCD induced changes in neurons and non-neuronal cells that may act together to promote the survival of the injured tissue. The release of ligands such as CCL2, in addition to possibly activating nociceptive neurons (maintaining the pain), may also act to preserve injured cells in the face of ischemia and hypoxia, for example, by promoting angiogenesis. Thus, somal hyperexcitability, as often said of inflammation, may represent a double edged sword. PMID:18958366

Growth enhancement by embryonic fibroblasts upon cotransplantation of noncommitted pig embryonic tissues with fully committed organs.

PubMed

Cohen, Sivan; Tchorsh-Yutsis, Dalit; Aronovich, Anna; Tal, Orna; Eventov-Friedman, Smadar; Katchman, Helena; Klionsky, Yael; Shezen, Elias; Reisner, Yair

2010-05-27

We recently defined the optimal gestational time windows for the transplantation of several embryonic tissues. We showed that the liver and kidney obtained from E28 pig embryos can grow and differentiate normally after transplantation, whereas 1 week earlier in gestation, these tissues develop into teratoma-like structures or fibrotic mass. In this study, we investigated whether cotransplantation of E28 with E21 tissue could control its tumorogenic potential, or alternatively whether the stem cells derived from the earlier tissue contribute to the growth of the more committed one. Pig embryonic precursors from E21 and E28 gestational age were transplanted alone or together, into nonobese diabetic/severe combined immunodeficiency mice, and their growth and differentiation was evaluated by immunohistology. In situ analysis, based on sex disparity between the E21 and E28 tissues, was used to identify the tissue source. In some experiments, mouse embryonic fibroblasts (MEF) were cotransplanted with E28 liver, and their effect was evaluated. E28 tissues could not abrogate the propensity of the cells within the undifferentiated tissue to form teratoma-like structures. However, E21 kidney or liver tissue markedly enhanced the growth and function of E28 kidney, liver, and heart grafts. Moreover, similar growth enhancement was observed on coimplantation of E28 liver tissue with MEF or on infusion of MEF culture medium, indicating that this enhancement is likely mediated through soluble factors secreted by the fibroblasts. Our results suggest a novel approach for the enhancement of growth and differentiation of transplanted embryonic tissues by the use of soluble factors secreted by embryonic fibroblasts.

Frequency-Dependent Activation of Glucose Utilization in the Superior Cervical Ganglion by Electrical Stimulation of Cervical Sympathetic Trunk

NASA Astrophysics Data System (ADS)

Yarowsky, Paul; Kadekaro, Massako; Sokoloff, Louis

1983-07-01

Electrical stimulation of the distal stump of the transected cervical sympathetic trunk produces a frequency-dependent activation of glucose utilization, measured by the deoxy[14C]glucose method, in the superior cervical ganglion of the urethane-anesthetized rat. The frequency dependence falls between 0-15 Hz; at 20 Hz the activation of glucose utilization is no greater than at 15 Hz. Deafferentation of the superior cervical ganglion by transection of the cervical sympathetic trunk does not diminish the rate of glucose utilization in the ganglion in the urethane-anesthetized rat. These results indicate that the rate of energy metabolism in an innervated neural structure is, at least in part, regulated by the impulse frequency of the electrical input to the structure, and this regulation may be an essential component of the mechanism of the coupling of metabolic activity to functional activity in the nervous system.

Sphenopalatine (nasal) ganglion: remote effects including "psychosomatic" symptoms, rage reaction, pain, and spasm.

PubMed

Ruskin, A P

1979-08-01

Many articles implicate the nasal ganglion in the production of remote symptoms and discuss treatment. Symptoms are primarily spastic, involving both visceral and voluntary muscles including muscle spasm in the neck, shoulder, and low back; asthma, hypertension, intestinal spasm; diarrhea, angina pectoris, uterine spasm; intractable hiccup, and many others. All these symptoms appear to have 2 common denominators. They are mediated by the autonomic nervous system and at least in some instances can be "psychosomatic." The sphenopalatine ganglion (SPG) is a major autonomic ganglion located superficially in the pterygopalatine fossa, with major afferent distribution to the entire nasopharynx and important connections with the trigeminal nerve, facial nerve, internal carotid artery plexus of the sympathetic nervous system and, as shown in the rat, direct connection with the anterior pituitary gland. This paper presents arguments supporting the following hypotheses: 1. The SPG probably has a crucial role in lower animals in declenching the reflex responses known collectively as the rage reaction. 2. The SPG is a major point of entry to the autonomic system exposed to pathologic influences and readily accessible for therapeutic influences and readily accessible for therapeutic intervention. 3. A wide variety of symptoms are produced or maintained by alteration in autonomic system tonus and some of these may be affected by intervention on the SPG. 4. The possible relationship of some symptoms and "psychosomatic" conditions to the autonomic nervous system and the rage reaction must be considered.20

Knock Down of Cell Division Cycle 16 Reveals an Inverse Relationship Between Lateral Root and Nodule Numbers and a Link to Auxin in Medicago truncatula

USDA-ARS?s Scientific Manuscript database

The post-embryonic development of lateral roots and nodules is a highly regulated process. Recent studies suggest the existence of cross talk and interdependency in the growth of these two organs. Although plant hormones including auxin and cytokinin appear to be key players in coordinating this cro...

Ectodomain shedding of Limbic System-Associated Membrane Protein (LSAMP) by ADAM Metallopeptidases promotes neurite outgrowth in DRG neurons.

PubMed

Sanz, Ricardo L; Ferraro, Gino B; Girouard, Marie-Pier; Fournier, Alyson E

2017-08-11

IgLONs are members of the immunoglobulin superfamily of cell adhesion proteins implicated in the process of neuronal outgrowth, cell adhesion and subdomain target recognition. IgLONs form homophilic and heterophilic complexes on the cell surface that repress or promote growth depending on the neuronal population, the developmental stage and surface repertoire of IgLON family members. In the present study, we identified a metalloproteinase-dependent mechanism necessary to promote growth in embryonic dorsal root ganglion cells (DRGs). Treatment of embryonic DRG neurons with pan-metalloproteinase inhibitors, tissue inhibitor of metalloproteinase-3, or an inhibitor of ADAM Metallopeptidase Domain 10 (ADAM10) reduces outgrowth from DRG neurons indicating that metalloproteinase activity is important for outgrowth. The IgLON family members Neurotrimin (NTM) and Limbic System-Associated Membrane Protein (LSAMP) were identified as ADAM10 substrates that are shed from the cell surface of DRG neurons. Overexpression of LSAMP and NTM suppresses outgrowth from DRG neurons. Furthermore, LSAMP loss of function decreases the outgrowth sensitivity to an ADAM10 inhibitor. Together our findings support a role for ADAM-dependent shedding of cell surface LSAMP in promoting outgrowth from DRG neurons.

[Low expression of activin A in mouse and human embryonic teratocarcinoma cells].

PubMed

Gordeeva, O F

2014-01-01

TGFP3 family factors play an important role in regulating the balance of self-renewal and differentiation of mouse and human pluripotent stem and embryonic teratocarcinoma cells. The expression patterns of TGFbeta family signaling ligands and functional roles of these signaling pathways differ significantly in mouse and human embryonic stem cells, but the activity and functional role of these factors in mouse and human embryonic teratocarcinoma cells were not sufficiently investigated. Comparative quantitative real-time PCR analysis of the expression of TGF@[beta] family factors in mouse embryonic stem, embryonic germ, and embryonic teratocarcinoma cells showed that embryonic teratocarcinoma cells express lower ActivinA than pluripotent stem cells but similar levels of factors Nodal, Lefty 1, TGFbeta1, BMP4, and GDF3. In human nullipotent embryonic teratocarcinoma PA-1 cells, most factors of the TGFbeta family (ACTIVINA, NODAL, LEFTY 1, BMP4, and GDF3) are expressed at lower levels than in human embryonic stem cells: Thus, in mouse and human nullipotent teratocarcinoma cells, theexpression of ActivinA is significantly reduced com- pared ivith embryonic stem cells. Presumably, these differences may be associated with changes in the functional activity of the respective signaling pathways and deregulation of proliferative and antiproliferative mechanisms in embryonic teratocarcinoma cells.

Enkephalins in the inferior mesenteric ganglion of the cat and in the area of the lower digestive tract innervated by this ganglion: quantification by radio-immunoassay and characterization by high pressure liquid chromatography.

PubMed

Cupo, A; Niel, J P; Miolan, J P; Jule, Y; Jarry, T

1988-01-01

Met-enkephalin, Leu-enkephalin and Met-enkephalin-Arg-Gly-Leu were quantified and characterized in the cat inferior mesenteric ganglion and in the area of the lower digestive tract innervated by this ganglion, including the proximal colon, distal colon and internal anal sphincter. In the structures studied, the concentrations of enkephalins expressed as femtomole/mg of wet tissue ranged from 66 to 160 with Met-enkephalin, from 15 to 45 with Leu-enkephalin and from 2 to 12 for Met-enkephalin-arg-gly-leu. In the lower digestive tract, the Met- and Leu-enkephalin content decreased from the proximal colon to the internal anal sphincter. The Met-enkephalin versus Leu-enkephalin ratio of the structures investigated were as follows: inferior mesenteric ganglion 3.2, proximal colon 4.4, distal colon 5, internal and sphincter 4.5. In individual samples of all the structures assayed the results of high pressure liquid chromatography (HPLC) analysis pointed to the presence of authentic Met- and Leu-enkephalin. HPLC analysis could not be carried out on Met-enkephalin-Arg-Gly-Leu due to the very low concentrations of this peptide in all the structures assayed. Our results, combined with those of previous immunohistochemical and physiological studies, support the idea that enkephalins are involved in the nervous control of the motility of the lower digestive tract.

Effects of alpha-lipoic acid on retinal ganglion cells, retinal thicknesses, and VEGF production in an experimental model of diabetes.

PubMed

Kan, Emrah; Alici, Ömer; Kan, Elif Kılıç; Ayar, Ahmet

2017-12-01

The purpose of the present study was to investigate the effect of alpha-lipoic acid (ALA) on the thicknesses of various retinal layers and on the numbers of retinal ganglion cells and vascular endothelial growth factor levels in experimental diabetic mouse retinas. Twenty-one male BALB/C mice were made diabetic by the intraperitoneal administration of streptozotocin (200 mg/kg). One week after the induction of diabetes, the mice were divided randomly into three groups: control group (non-diabetic mice treated with alpha-lipoic acid, n = 7), diabetic group (diabetic mice without treatment, n = 7), and alpha-lipoic acid treatment group (diabetic mice with alpha-lipoic acid treatment, n = 7). At the end of the 8th week, the thicknesses of the inner nuclear layer (INL), outer nuclear layer (ONL), and full-length retina were measured; also retinal ganglion cells and VEGF expressions were counted on the histological sections of the mouse retinas and compared with each other. The thicknesses of the full-length retina, ONL, and INL were significantly reduced in the diabetic group compared to the control and ALA treatment groups (p = 0.001), whereas the thicknesses of these layers did not show a significant difference between ALA treatment and control groups. The number of ganglion cells in the diabetic group was significantly lower than those in the control and ALA treatment groups (p = 0.001). The VEGF expression was significantly higher in the diabetic group and mostly observed in the ganglion cell and inner nuclear layers compared to the control and ALA treatment groups (p = 0.001). Therefore, the number of ganglion cells and VEGF levels did not show significant differences between the ALA treatment and control groups (p = 0.7). Our results show that alpha-lipoic acid treatment may have an impact on reducing VEGF levels, protecting ganglion cells, and preserving the thicknesses of the inner and outer layers in diabetic mouse retinas.

Maternal Lifestyle Impairs Embryonic Growth: The Rotterdam Periconception Cohort.

PubMed

Van Dijk, Matthijs R; Borggreven, Nicole V; Willemsen, Sten P; Koning, Anton H J; Steegers-Theunissen, Régine P M; Koster, Maria P H

2018-06-01

Previously, embryonic growth has been assumed to be uniform, but in recent years, it has become more clear that genetic and environmental factors may influence the intrauterine environment and therefore embryonic growth trajectories as well as pregnancy course and outcome. The objective of this study was to investigate associations between modifiable maternal nutrition and lifestyle factors during the periconception period and embryonic growth. We established a prospective cohort including 342 women less than 13 weeks pregnant. At enrollment, women filled out a questionnaire regarding demographic and medical data and a validated food frequency questionnaire. Participants received multiple 3-dimensional ultrasound examinations up until the 12th week of pregnancy, and crown-rump length (CRL) and embryonic volume (EV) were measured offline using V-Scope Virtual Reality software (version 1.0.0) in a Barco I-Space. Associations between maternal periconception vegetable and fruit intake, folic acid supplement use, smoking, and alcohol consumption and embryonic growth measurements were assessed by linear mixed models adjusted for potential confounders. No or postconception initiation of folic acid supplement use was significantly associated with a 0.76 mm (-7.8%) and 1.63 mm (-3.7%) smaller CRL and a 0.01 cm 3 (-19.5%) and 0.86 cm 3 (-12.2%) smaller EV at 7 +0 and 11 +0 weeks of gestation, respectively. Smoking, alcohol consumption, and inadequate fruit and vegetable intake showed weaker associations with embryonic growth parameters. These results emphasize the influence of periconceptional maternal folic acid supplement use on embryonic growth. Results regarding maternal nutrition and lifestyle factors also suggest an association with embryonic growth, but this has to be confirmed in a larger study.

How the embryonic chick brain twists.

PubMed

Chen, Zi; Guo, Qiaohang; Dai, Eric; Forsch, Nickolas; Taber, Larry A

2016-11-01

During early development, the tubular embryonic chick brain undergoes a combination of progressive ventral bending and rightward torsion, one of the earliest organ-level left-right asymmetry events in development. Existing evidence suggests that bending is caused by differential growth, but the mechanism for the predominantly rightward torsion of the embryonic brain tube remains poorly understood. Here, we show through a combination of in vitro experiments, a physical model of the embryonic morphology and mechanics analysis that the vitelline membrane (VM) exerts an external load on the brain that drives torsion. Our theoretical analysis showed that the force is of the order of 10 micronewtons. We also designed an experiment to use fluid surface tension to replace the mechanical role of the VM, and the estimated magnitude of the force owing to surface tension was shown to be consistent with the above theoretical analysis. We further discovered that the asymmetry of the looping heart determines the chirality of the twisted brain via physical mechanisms, demonstrating the mechanical transfer of left-right asymmetry between organs. Our experiments also implied that brain flexure is a necessary condition for torsion. Our work clarifies the mechanical origin of torsion and the development of left-right asymmetry in the early embryonic brain. © 2016 The Author(s).

Root-type-specific plasticity in response to localized high nitrate supply in maize (Zea mays)

PubMed Central

Yu, Peng; Hochholdinger, Frank; Li, Chunjian

2015-01-01

Background and Aims Shoot-borne roots contribute to most of the nutrient uptake throughout the life cycle of maize (Zea mays). Compared with numerous studies with embryonic roots, detailed information on the phenotypic plasticity of shoot-borne roots in response to a heterogeneous nitrogen supply is scarce. The present study therefore provides a comprehensive profile of fine-scale plastic responses of distinct root types to localized high nitrate supply. Methods Seedlings of the maize inbred line B73 were grown in split-root systems. The anatomy and morphological plasticity of the primary root and the roots initiated from the 2nd, 5th and 7th shoot nodes, and their lateral roots, were studied in response to local high nitrate supply to one side of the root system. Key Results In contrast to the insensitivity of axial roots, local high nitrate supply increased the length of 1st-order lateral roots on the primary root and the three whorls of shoot-borne roots at different growth stages, and increased the density of 1st-order lateral roots on the 7th shoot-borne root after silking. The length and density of 2nd-order lateral roots on the three whorls of shoot-borne roots displayed a more flexible response to local high nitrate than 1st-order lateral roots. Root diameter and number, and total area and diameter of metaxylem vessels increased from the primary root to early and then later developed shoot-borne roots, which showed a positive relationship with shoot growth and N accumulation. Conclusions Maize axial roots and lateral roots responded differently to local high nitrate, and this was related to their function. The extent of morphological plasticity of lateral roots in response to local high nitrate depended on the initiation time of the shoot-borne roots on which the lateral roots developed. Morphological plasticity was higher on 2nd-order than on 1st-order lateral roots. The results suggest that higher order lateral root branching might be a potential target

Root-type-specific plasticity in response to localized high nitrate supply in maize (Zea mays).

PubMed

Yu, Peng; Hochholdinger, Frank; Li, Chunjian

2015-10-01

Shoot-borne roots contribute to most of the nutrient uptake throughout the life cycle of maize (Zea mays). Compared with numerous studies with embryonic roots, detailed information on the phenotypic plasticity of shoot-borne roots in response to a heterogeneous nitrogen supply is scarce. The present study therefore provides a comprehensive profile of fine-scale plastic responses of distinct root types to localized high nitrate supply. Seedlings of the maize inbred line B73 were grown in split-root systems. The anatomy and morphological plasticity of the primary root and the roots initiated from the 2nd, 5th and 7th shoot nodes, and their lateral roots, were studied in response to local high nitrate supply to one side of the root system. In contrast to the insensitivity of axial roots, local high nitrate supply increased the length of 1st-order lateral roots on the primary root and the three whorls of shoot-borne roots at different growth stages, and increased the density of 1st-order lateral roots on the 7th shoot-borne root after silking. The length and density of 2nd-order lateral roots on the three whorls of shoot-borne roots displayed a more flexible response to local high nitrate than 1st-order lateral roots. Root diameter and number, and total area and diameter of metaxylem vessels increased from the primary root to early and then later developed shoot-borne roots, which showed a positive relationship with shoot growth and N accumulation. Maize axial roots and lateral roots responded differently to local high nitrate, and this was related to their function. The extent of morphological plasticity of lateral roots in response to local high nitrate depended on the initiation time of the shoot-borne roots on which the lateral roots developed. Morphological plasticity was higher on 2nd-order than on 1st-order lateral roots. The results suggest that higher order lateral root branching might be a potential target for genetic improvement in future maize breeding. �

Lumbar plexus in patients with chronic inflammatory demyelinating polyneuropathy: Evaluation with 3D nerve-sheath signal increased with inked rest-tissue rapid acquisition of relaxation enhancement imaging (3D SHINKEI).

PubMed

Hiwatashi, Akio; Togao, Osamu; Yamashita, Koji; Kikuchi, Kazufumi; Kamei, Ryotato; Momosaka, Daichi; Ogata, Hidenori; Yamasaki, Ryo; Yoneyama, Masami; Kira, Jun-Ichi; Honda, Hiroshi

2017-08-01

To evaluate whether 3D SHINKEI in the lumbar plexus could identify patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Twenty-one patients with CIDP and 15 non-CIDP patients were studied in this retrospective study. The SNR, contrast-to-noise ratio (CNR), contrast ratio (CR) and the size of the lumbar ganglions and roots were measured. Statistical analyses were performed with Mann-Whitney U test and receiver operating characteristics (ROC) analysis. The SNRs of the ganglions and roots were larger in patients with CIDP (8.30±4.87 and 8.24±4.92) than in non-CIDP patients (4.95±2.05 and 5.08±1.97, P<0.0001, respectively). The CNRs of the ganglions and roots were larger in patients with CIDP (40.79±43.19 and 37.16±48.31) than in non-CIDP patients (25.90±10.41 and 18.37±32.83, P<0.0001, respectively). The CRs of the ganglions and roots were larger in patients with CIDP (0.74±0.13 and 0.66±0.17) than in non-CIDP patients (0.72±0.12 and 0.50±0.17, P=0.004 and P<0.0001, respectively). The sizes of the ganglions and the roots were larger in patients with CIDP (6.62±1.81mm and 5.76±3.24mm) than in non-CIDP patients (5.23±1.17mm and 4.24±1.11mm, P<0.0001, respectively). ROC analysis showed the best diagnostic performance with the CNR of the roots. Patients with CIDP could be distinguished from controls on 3D SHINKEI. Copyright © 2017. Published by Elsevier B.V.

Differential localization of cytoplasmic myosin II isoforms A and B in avian interphase and dividing embryonic and immortalized cardiomyocytes and other cell types in vitro

NASA Technical Reports Server (NTRS)

Conrad, A. H.; Jaffredo, T.; Conrad, G. W.; Spooner, B. S. (Principal Investigator)

1995-01-01

Two principal isoforms of cytoplasmic myosin II, A and B (CMIIA and CMIIB), are present in different proportions in different tissues. Isoform-specific monoclonal and polyclonal antibodies to avian CMIIA and CMIIB reveal the cellular distributions of these isoforms in interphase and dividing embryonic avian cardiac, intestinal epithelial, spleen, and dorsal root ganglia cells in primary cell culture. Embryonic cardiomyocytes react with antibodies to CMIIB but not to CMIIA, localize CMIIB in stress-fiber-like-structures during interphase, and markedly concentrate CMIIB in networks in the cleavage furrow during cytokinesis. In contrast, cardiac fibroblasts localize both CMIIA and CMIIB in stress fibers and networks during interphase, and demonstrate slight and independently regulated concentration of CMIIA and CMIIB in networks in their cleavage furrows. V-myc-immortalized cardiomyocytes, an established cell line, have regained the ability to express CMIIA, as well as CMIIB, and localize both CMIIA and CMIIB in stress fibers and networks in interphase cells and in cleavage furrows in dividing cells. Conversely, some intestinal epithelial, spleen, and dorsal root ganglia interphase cells express only CMIIA, organized primarily in networks. Of these, intestinal epithelial cells express both CMIIA and CMIIB when they divide, whereas some dividing cells from both spleen and dorsal root ganglia express only CMIIA and concentrate it in their cleavage furrows. These results suggest that within a given tissue, different cell types express different isoforms of CMII, and that cells expressing either CMIIA or CMIIB alone, or simultaneously, can form a cleavage furrow and divide.

The periconception maternal cardiovascular risk profile influences human embryonic growth trajectories in IVF/ICSI pregnancies.

PubMed

Wijnands, K P J; van Uitert, E M; Roeters van Lennep, J E; Koning, A H J; Mulders, A G M G J; Laven, J S E; Steegers, E A P; Steegers-Theunissen, R P M

2016-06-01

Is the maternal cardiovascular (CV) risk profile associated with human embryonic growth trajectories and does the mode of conception affect this association? This small study suggests that the maternal CV risk profile is inversely associated with first trimester embryonic growth trajectories in in vitro fertilization (IVF)/intra-cytoplasmic sperm injection (ICSI) pregnancies, but not in spontaneously conceived pregnancies. Maternal high-blood pressure and smoking affect placental function, accompanied by increased risk of fetal growth restriction and low-birthweight. Mothers who experience pregnancies complicated by fetal growth restriction are at increased risk of CV disease in later life. In a prospective periconception birth cohort conducted in a tertiary hospital, 111 singleton ongoing pregnancies with reliable pregnancy dating, no pre-existing maternal disease and no malformed live borns were investigated. Spontaneously conceived pregnancies with a reliable first day of the last menstrual period and a regular menstrual cycle of 25-31 days only (n = 66) and IVF/ICSI pregnancies (n = 45) were included. Women underwent weekly three-dimensional ultrasound scans (3D US) from 6- to 13-week gestational age. To estimate embryonic growth, serial crown-rump length (CRL) measurements were performed using the V-Scope software in a BARCO I-Space. Maternal characteristics and CV risk factors were collected by self-administered questionnaires. The CV risk profile was created based on a score of risk factors, including maternal age, body-mass index, CV disease in the family, diet and smoking. Quartiles of the CV risk score were calculated. Associations between the CV risk score and embryonic growth were assessed using square root transformed CRL in multivariable linear mixed model analyses. From the 111 included pregnancies, 696 3D US data sets were obtained of which 637 (91.5%) CRLs could be measured. In the total group, The CV risk score was inversely, but not significantly

Ethanol Inactivated Mouse Embryonic Fibroblasts Maintain the Self-Renew and Proliferation of Human Embryonic Stem Cells.

PubMed

Huang, Boxian; Ning, Song; Zhuang, Lili; Jiang, Chunyan; Cui, Yugui; Fan, Guoping; Qin, Lianju; Liu, Jiayin

2015-01-01

Conventionally, mouse embryonic fibroblasts (MEFs) inactivated by mitomycin C or irradiation were applied to support the self-renew and proliferation of human embryonic stem cells (hESCs). To avoid the disadvangtages of mitomycin C and irradiation, here MEFs were treated by ethanol (ET). Our data showed that 10% ET-inactivated MEFs (eiMEFs) could well maintain the self-renew and proliferation of hESCs. hESCs grown on eiMEFs expressed stem cell markers of NANOG, octamer-binding protein 4 (OCT4), stage-specific embryonic antigen-4 (SSEA4) and tumour related antigen-1-81 (TRA-1-81), meanwhile maintained normal karyotype after long time culture. Also, hESCs cocultured with eiMEFs were able to form embryoid body (EB) in vitro and develop teratoma in vivo. Moreover, eiMEFs could keep their nutrient functions after long time cryopreservation. Our results indicate that the application of eiMEF in hESCs culture is safe, economical and convenient, thus is a better choice.

Embryonic stem cells: testing the germ-cell theory.

PubMed

Hochedlinger, Konrad

2011-10-25

The exact cellular origin of embryonic stem cells remains elusive. Now a new study provides compelling evidence that embryonic stem cells, established under conventional culture conditions, originate from a transient germ-cell state. Copyright © 2011 Elsevier Ltd. All rights reserved.

Diversity and Complexity in Chromatin Recognition by TFII-I Transcription Factors in Pluripotent Embryonic Stem Cells and Embryonic Tissues

PubMed Central

Makeyev, Aleksandr V.; Enkhmandakh, Badam; Hong, Seung-Hyun; Joshi, Pujan; Shin, Dong-Guk; Bayarsaihan, Dashzeveg

2012-01-01

GTF2I and GTF2IRD1 encode a family of closely related transcription factors TFII-I and BEN critical in embryonic development. Both genes are deleted in Williams-Beuren syndrome, a complex genetic disorder associated with neurocognitive, craniofacial, dental and skeletal abnormalities. Although genome-wide promoter analysis has revealed the existence of multiple TFII-I binding sites in embryonic stem cells (ESCs), there was no correlation between TFII-I occupancy and gene expression. Surprisingly, TFII-I recognizes the promoter sequences enriched for H3K4me3/K27me3 bivalent domain, an epigenetic signature of developmentally important genes. Moreover, we discovered significant differences in the association between TFII-I and BEN with the cis-regulatory elements in ESCs and embryonic craniofacial tissues. Our data indicate that in embryonic tissues BEN, but not the highly homologous TFII-I, is primarily recruited to target gene promoters. We propose a “feed-forward model” of gene regulation to explain the specificity of promoter recognition by TFII-I factors in eukaryotic cells. PMID:22970219

Diversity and complexity in chromatin recognition by TFII-I transcription factors in pluripotent embryonic stem cells and embryonic tissues.

PubMed

Makeyev, Aleksandr V; Enkhmandakh, Badam; Hong, Seung-Hyun; Joshi, Pujan; Shin, Dong-Guk; Bayarsaihan, Dashzeveg

2012-01-01

GTF2I and GTF2IRD1 encode a family of closely related transcription factors TFII-I and BEN critical in embryonic development. Both genes are deleted in Williams-Beuren syndrome, a complex genetic disorder associated with neurocognitive, craniofacial, dental and skeletal abnormalities. Although genome-wide promoter analysis has revealed the existence of multiple TFII-I binding sites in embryonic stem cells (ESCs), there was no correlation between TFII-I occupancy and gene expression. Surprisingly, TFII-I recognizes the promoter sequences enriched for H3K4me3/K27me3 bivalent domain, an epigenetic signature of developmentally important genes. Moreover, we discovered significant differences in the association between TFII-I and BEN with the cis-regulatory elements in ESCs and embryonic craniofacial tissues. Our data indicate that in embryonic tissues BEN, but not the highly homologous TFII-I, is primarily recruited to target gene promoters. We propose a "feed-forward model" of gene regulation to explain the specificity of promoter recognition by TFII-I factors in eukaryotic cells.

Genetic Dissection of Maize Embryonic Callus Regenerative Capacity Using Multi-Locus Genome-Wide Association Studies

PubMed Central

Ma, Langlang; Liu, Min; Yan, Yuanyuan; Qing, Chunyan; Zhang, Xiaoling; Zhang, Yanling; Long, Yun; Wang, Lei; Pan, Lang; Zou, Chaoying; Li, Zhaoling; Wang, Yanli; Peng, Huanwei; Pan, Guangtang; Jiang, Zhou; Shen, Yaou

2018-01-01

The regenerative capacity of the embryonic callus, a complex quantitative trait, is one of the main limiting factors for maize transformation. This trait was decomposed into five traits, namely, green callus rate (GCR), callus differentiating rate (CDR), callus plantlet number (CPN), callus rooting rate (CRR), and callus browning rate (CBR). To dissect the genetic foundation of maize transformation, in this study multi-locus genome-wide association studies (GWAS) for the five traits were performed in a population of 144 inbred lines genotyped with 43,427 SNPs. Using the phenotypic values in three environments and best linear unbiased prediction (BLUP) values, as a result, a total of 127, 56, 160, and 130 significant quantitative trait nucleotides (QTNs) were identified by mrMLM, FASTmrEMMA, ISIS EM-BLASSO, and pLARmEB, respectively. Of these QTNs, 63 QTNs were commonly detected, including 15 across multiple environments and 58 across multiple methods. Allele distribution analysis showed that the proportion of superior alleles for 36 QTNs was <50% in 31 elite inbred lines. Meanwhile, these superior alleles had obviously additive effect on the regenerative capacity. This indicates that the regenerative capacity-related traits can be improved by proper integration of the superior alleles using marker-assisted selection. Moreover, a total of 40 candidate genes were found based on these common QTNs. Some annotated genes were previously reported to relate with auxin transport, cell fate, seed germination, or embryo development, especially, GRMZM2G108933 (WOX2) was found to promote maize transgenic embryonic callus regeneration. These identified candidate genes will contribute to a further understanding of the genetic foundation of maize embryonic callus regeneration. PMID:29755499

Embryonic integument and "molts" in Manduca sexta (Insecta, Lepidoptera).

PubMed

Ziese, Stefanie; Dorn, August

2003-02-01

In Manduca sexta the germ band is formed 12 h post-oviposition (p.o.) (=10% development completed) and is located above the yolk at the egg surface. The cells show a polar organization. They are engaged in the uptake and degradation of yolk globules, pinched off from the yolk cells. This process can be observed in the integumental cells during the first growth phase of the embryo that lasts until "katatrepsis," an embryonic movement that takes place at 40% development completed. At 37% development completed, the ectoderm deposits a thin membrane at its apical surface, the first embryonic membrane, which detaches immediately before katatrepsis. The second period of embryonic growth--from katatrepsis to 84 h p.o. (70% development completed)--starts with the deposition of a second embryonic membrane that is somewhat thicker than the first one and shows a trilaminar, cuticulin-like structure. Whereas the apical cell surface is largely smooth during the deposition of the first embryonic membrane, it forms microvilli during deposition of the second one. At the same time, uptake of formed yolk material ceases and the epidermal cells now contain clusters of mitochondria below the apical surface. Rough endoplasmic reticulum (RER) increases in the perinuclear region. The second embryonic membrane detaches about 63 h p.o. At 69 h p.o., a new generation of microvilli forms and islands of a typical cuticulin layer indicate the onset of the deposition of the larval cuticle. The third growth phase is characterized by a steady increase in the embryo length, the deposition of the larval procuticle, and by cuticular tanning at about 100 h p.o. Beginning at that stage, electron-lucent vesicles aggregate below the epidermal surface and are apparently released below the larval cuticle. Manduca sexta is the first holometabolous insect in which the deposition of embryonic membranes and cuticles has been examined by electron microscopy. In correspondence with hemimetabolous insects, the

Developmental changes in expression of GABAA receptor-channels in rat intrinsic cardiac ganglion neurones

PubMed Central

Fischer, Harald; Harper, Alexander A; Anderson, Colin R; Adams, David J

2005-01-01

The effects of γ-aminobutyric acid (GABA) on the electrophysiological properties of intracardiac neurones were investigated in the intracardiac ganglion plexus in situ and in dissociated neurones from neonatal, juvenile and adult rat hearts. Focal application of GABA evoked a depolarizing, excitatory response in both intact and dissociated intracardiac ganglion neurones. Under voltage clamp, both GABA and muscimol elicited inward currents at −60 mV in a concentration-dependent manner. The fast, desensitizing currents were mimicked by the GABAA receptor agonists muscimol and taurine, and inhibited by the GABAA receptor antagonists, bicuculline and picrotoxin. The GABAA0 antagonist (1,2,5,6-tetrahydropyridin-4-yl)methyl phosphonic acid (TPMPA), had no effect on GABA-induced currents, suggesting that GABAA receptor-channels mediate the response. The GABA-evoked current amplitude recorded from dissociated neurones was age dependent whereby the peak current density measured at −100 mV was ∼ 20 times higher for intracardiac neurones obtained from neonatal rats (P2–5) compared with adult rats (P45–49). The decrease in GABA sensitivity occurred during the first two postnatal weeks and coincides with maturation of the sympathetic innervation of the rat heart. Immunohistochemical staining using antibodies against GABA demonstrate the presence of GABA in the intracardiac ganglion plexus of the neonatal rat heart. Taken together, these results suggest that GABA and taurine may act as modulators of neurotransmission and cardiac function in the developing mammalian intrinsic cardiac nervous system. PMID:15731187

Expression and function of system N glutamine transporters (SN1/SN2 or SNAT3/SNAT5) in retinal ganglion cells.

PubMed

Umapathy, Nagavedi S; Dun, Ying; Martin, Pamela M; Duplantier, Jennifer N; Roon, Penny; Prasad, Puttur; Smith, Sylvia B; Ganapathy, Vadivel

2008-11-01

Glutamine transport is essential for the glutamate-glutamine cycle, which occurs between neurons and glia. System N, consisting of SN1 (SNAT3) and SN2 (SNAT5), is the principal mediator of glutamine transport in retinal Müller cells. Mediators of glutamine transport in retinal ganglion cells were investigated. The relative contributions of various transport systems for glutamine uptake (systems N, A, L, y+L, ASCT, and ATB(0,+)) were examined in RGC-5 cells based on differential features of the individual transport systems. mRNA for the genes encoding members of these transport systems were analyzed by RT-PCR. Based on these data, SN1 and SN2 were analyzed in mouse retina, RGC-5 cells, and primary mouse ganglion cells (GCs) by in situ hybridization (ISH), immunofluorescence (IF), and Western blotting. Three transport systems--N, A, and L--participated in glutamine uptake in RGC-5 cells. System N was the principal contributor; systems A and L contributed considerably less. ISH and IF revealed SN1 and SN2 expression in the ganglion, inner nuclear, and photoreceptor cell layers. SN1 and SN2 colocalized with the ganglion cell marker Thy 1.2 and with the Müller cell marker vimentin, confirming their presence in both retinal cell types. SN1 and SN2 proteins were detected in primary mouse GCs. These findings suggest that in addition to its role in glutamine uptake in retinal glial cells, system N contributes significantly to glutamine uptake in ganglion cells and, hence, contributes to the retinal glutamate-glutamine cycle.

Autophagy in Human Embryonic Stem Cells

PubMed Central

Tra, Thien; Gong, Lan; Kao, Lin-Pin; Li, Xue-Lei; Grandela, Catarina; Devenish, Rodney J.; Wolvetang, Ernst; Prescott, Mark

2011-01-01

Autophagy (macroautophagy) is a degradative process that involves the sequestration of cytosolic material including organelles into double membrane vesicles termed autophagosomes for delivery to the lysosome. Autophagy is essential for preimplantation development of mouse embryos and cavitation of embryoid bodies. The precise roles of autophagy during early human embryonic development, remain however largely uncharacterized. Since human embryonic stem cells constitute a unique model system to study early human embryogenesis we investigated the occurrence of autophagy in human embryonic stem cells. We have, using lentiviral transduction, established multiple human embryonic stem cell lines that stably express GFP-LC3, a fluorescent marker for the autophagosome. Each cell line displays both a normal karyotype and pluripotency as indicated by the presence of cell types representative of the three germlayers in derived teratomas. GFP expression and labelling of autophagosomes is retained after differentiation. Baseline levels of autophagy detected in cultured undifferentiated hESC were increased or decreased in the presence of rapamycin and wortmannin, respectively. Interestingly, autophagy was upregulated in hESCs induced to undergo differentiation by treatment with type I TGF-beta receptor inhibitor SB431542 or removal of MEF secreted maintenance factors. In conclusion we have established hESCs capable of reporting macroautophagy and identify a novel link between autophagy and early differentiation events in hESC. PMID:22110659

Association Between Regular Cannabis Use and Ganglion Cell Dysfunction.

PubMed

Schwitzer, Thomas; Schwan, Raymund; Albuisson, Eliane; Giersch, Anne; Lalanne, Laurence; Angioi-Duprez, Karine; Laprevote, Vincent

2017-01-01

Because cannabis use is a major public health concern and cannabis is known to act on central neurotransmission, studying the retinal ganglion cells in individuals who regularly use cannabis is of interest. To determine whether the regular use of cannabis could alter the function of retinal ganglion cells in humans. For this case-control study, individuals who regularly use cannabis, as well as healthy controls, were recruited, and data were collected from February 11 to October 28, 2014. Retinal function was used as a direct marker of brain neurotransmission abnormalities in complex mental phenomena. Amplitude and implicit time of the N95 wave on results of pattern electroretinography. Twenty-eight of the 52 participants were regular cannabis users (24 men and 4 women; median age, 22 years [95% CI, 21-24 years]), and the remaining 24 were controls (20 men and 4 women; median age, 24 years [95% CI, 23-27 years]). There was no difference between groups in terms of age (P = .13) or sex (P = .81). After adjustment for the number of years of education and alcohol use, there was a significant increase for cannabis users of the N95 implicit time on results of pattern electroretinography (median, 98.6 milliseconds [95% CI, 93.4-99.5]) compared with controls (median, 88.4 milliseconds [95% CI, 85.0-91.1]), with 8.4 milliseconds as the median of the differences (95% CI, 4.9-11.5; P < .001, Wald logistic regression). A receiver operating characteristic curve analysis (area under the curve, 0.84 [95% CI, 0.73-0.95]; P < .001) revealed, for a cutoff value of 91.13 milliseconds, a sensitivity of 78.6% (95% CI, 60.5%-89.8%) and a specificity of 75.0% (95% CI, 55.1%-88.0%) for correctly classifying both cannabis users and controls in their corresponding group. The positive predictive value was 78.6% (95% CI, 60.5%-89.8%), and the negative predictive value was 75.0% (95% CI, 55.1%-88.0%). Our results demonstrate a delay in transmission of action potentials by the

Promotion of hair follicle development and trichogenesis by Wnt-10b in cultured embryonic skin and in reconstituted skin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouji, Yukiteru; Yoshikawa, Masahide; Shiroi, Akira

2006-06-30

We previously showed that Wnt-10b promoted the differentiation of primary skin epithelial cells (MPSEC) toward hair shaft and inner root sheath of the hair follicle (IRS) cells in vitro. In the present study, we found that Wnt-10b promotes the development of hair follicles using a culture of mouse embryonic skin tissue and trichogenesis using a reconstitution experiment with nude mice. Hair follicle development was observed in skin taken from mouse embryos on embryonic day 10.5 following a 2-day culture with recombinant Wnt-10b (rWnt-10b), however, not without rWnt-10b. Brown hair growth was observed at the site of reconstituted skin in Balb/cmore » nude mice where dermal fibroblasts and keratinocytes, derived from C3H/HeN new born mice, were transplanted with Wnt-10b-producing COS cells (Wnt-COS). Without the co-transplantation of Wnt-COS, no hair growth was observed. Our results suggest an important role of Wnt-10b in the initiation of hair follicle development and following trichogenesis.« less

The primary role of zebrafish nanog is in extra-embryonic tissue.

PubMed

Gagnon, James A; Obbad, Kamal; Schier, Alexander F

2018-01-09

The role of the zebrafish transcription factor Nanog has been controversial. It has been suggested that Nanog is primarily required for the proper formation of the extra-embryonic yolk syncytial layer (YSL) and only indirectly regulates gene expression in embryonic cells. In an alternative scenario, Nanog has been proposed to directly regulate transcription in embryonic cells during zygotic genome activation. To clarify the roles of Nanog, we performed a detailed analysis of zebrafish nanog mutants. Whereas zygotic nanog mutants survive to adulthood, maternal-zygotic (MZ nanog ) and maternal mutants exhibit developmental arrest at the blastula stage. In the absence of Nanog, YSL formation and epiboly are abnormal, embryonic tissue detaches from the yolk, and the expression of dozens of YSL and embryonic genes is reduced. Epiboly defects can be rescued by generating chimeric embryos of MZ nanog embryonic tissue with wild-type vegetal tissue that includes the YSL and yolk cell. Notably, cells lacking Nanog readily respond to Nodal signals and when transplanted into wild-type hosts proliferate and contribute to embryonic tissues and adult organs from all germ layers. These results indicate that zebrafish Nanog is necessary for proper YSL development but is not directly required for embryonic cell differentiation. © 2018. Published by The Company of Biologists Ltd.

Delayed rectifier K channels contribute to contrast adaptation in mammalian retinal ganglion cells

PubMed Central

Weick, Michael; Demb, Jonathan B.

2011-01-01

SUMMARY Retinal ganglion cells adapt by reducing their sensitivity during periods of high contrast. Contrast adaptation in the firing response depends on both presynaptic and intrinsic mechanisms. Here, we investigated intrinsic mechanisms for contrast adaptation in OFF Alpha ganglion cells in the in vitro guinea pig retina. Using either visual stimulation or current injection, we show that brief depolarization evoked spiking and suppressed firing during subsequent depolarization. The suppression could be explained by Na channel inactivation, as shown in salamander cells. However, brief hyperpolarization in the physiological range (5–10 mV) also suppressed firing during subsequent depolarization. This suppression was sensitive selectively to blockers of delayed-rectifier K channels (KDR). Somatic membrane patches showed TEA-sensitive KDR currents with activation near −25 mV and removal of inactivation at voltages negative to Vrest. Brief periods of hyperpolarization apparently remove KDR inactivation and thereby increase the channel pool available to suppress excitability during subsequent depolarization. PMID:21745646

Atypical fibrosarcomas derived from cutaneous ganglion cell-like cells in 2 domestic Djungarian hamsters (Phodopus sungorus).

PubMed

Kondo, Hirotaka; Onuma, Mamoru; Shibuya, Hisashi; Sato, Tsuneo; Abbott, Jeffrey R

2011-07-01

Androgen-dependent atypical fibromas are benign tumors derived from ganglion-cell-like cells that are particular to Djungarian hamsters (Phodopus sungorus). Masses excised from 2 hamsters were composed of pleomorphic ganglion cell-like cells supported by small to moderate amounts of collagenous matrix. Intracytoplasmic fibrils were present in silver-stained sections, and immunohistochemistry showed that the cells expressed vimentin, androgen receptor, and, in one case, estrogen receptor α. In contrast to previously reported atypical fibromas, these tumors had features of anaplasia and were locally invasive. We diagnosed the tumors as atypical fibrosarcomas and consider them an unusual malignant counterpart of atypical fibroma. Copyright 2011 by the American Association for Laboratory Animal Science

GDF15 is elevated in mice following retinal ganglion cell death and in glaucoma patients

PubMed Central

Ban, Norimitsu; Siegfried, Carla J.; Lin, Jonathan B.; Shui, Ying-Bo; Sein, Julia; Pita-Thomas, Wolfgang; Sene, Abdoulaye; Santeford, Andrea; Gordon, Mae; Lamb, Rachel; Dong, Zhenyu; Kelly, Shannon C.; Cavalli, Valeria; Yoshino, Jun

2017-01-01

Glaucoma is the second leading cause of blindness worldwide. Physicians often use surrogate endpoints to monitor the progression of glaucomatous neurodegeneration. These approaches are limited in their ability to quantify disease severity and progression due to inherent subjectivity, unreliability, and limitations of normative databases. Therefore, there is a critical need to identify specific molecular markers that predict or measure glaucomatous neurodegeneration. Here, we demonstrate that growth differentiation factor 15 (GDF15) is associated with retinal ganglion cell death. Gdf15 expression in the retina is specifically increased after acute injury to retinal ganglion cell axons and in a murine chronic glaucoma model. We also demonstrate that the ganglion cell layer may be one of the sources of secreted GDF15 and that GDF15 diffuses to and can be detected in aqueous humor (AH). In validating these findings in human patients with glaucoma, we find not only that GDF15 is increased in AH of patients with primary open angle glaucoma (POAG), but also that elevated GDF15 levels are significantly associated with worse functional outcomes in glaucoma patients, as measured by visual field testing. Thus, GDF15 maybe a reliable metric of glaucomatous neurodegeneration, although further prospective validation studies will be necessary to determine if GDF15 can be used in clinical practice. PMID:28469085

Rhein Induces Oxidative Stress and Apoptosis in Mouse Blastocysts and Has Immunotoxic Effects during Embryonic Development.

PubMed

Huang, Chien-Hsun; Chan, Wen-Hsiung

2017-09-20

Rhein, a glucoside chemical compound found in a traditional Chinese medicine derived from the roots of rhubarb, induces cell apoptosis and is considered to have high potential as an antitumor drug. Several previous studies showed that rhein can inhibit cell proliferation and trigger mitochondria-related or endoplasmic reticulum (ER) stress-dependent apoptotic processes. However, the side effects of rhein on pre- and post-implantation embryonic development remain unclear. Here, we show that rhein has cytotoxic effects on blastocyst-stage mouse embryos and induces oxidative stress and immunotoxicity in mouse fetuses. Blastocysts incubated with 5-20 μM rhein showed significant cell apoptosis, as well as decreases in their inner cell mass cell numbers and total cell numbers. An in vitro development assay showed that rhein affected the developmental potentials of both pre- and post-implantation embryos. Incubation of blastocysts with 5-20 μM rhein was associated with increased resorption of post-implantation embryos and decreased fetal weight in an embryo transfer assay. Importantly, in an in vivo model, intravenous injection of dams with rhein (1, 3, and 5 mg/kg body weight/day) for four days resulted in apoptosis of blastocyst-stage embryos, early embryonic developmental injury, and decreased fetal weight. Intravenous injection of dams with 5 mg/kg body weight/day rhein significantly increased the total reactive oxygen species (ROS) content of fetuses and the transcription levels of antioxidant proteins in fetal livers. Additional work showed that rhein induced apoptosis through ROS generation, and that prevention of apoptotic processes effectively rescued the rhein-induced injury effects on embryonic development. Finally, the transcription levels of the innate-immunity related genes, CXCL1 , IL-1 β and IL-8 , were down-regulated in the fetuses of dams that received intravenous injections of rhein. These results collectively show that rhein has the potential to

Monosaccharide uptake by erythrocytes of the embryonic and adult chicken.

PubMed

Ingermann, R L; Stock, M K; Metcalfe, J; Bissonnette, J M

1985-01-01

Rates of monosaccharide uptake by adult and 10-18 day old embryonic chicken erythrocytes were quantitated. The rate of carrier-mediated, stereospecific transport decreased 28% from day 10 to day 14 of incubation and was unchanged thereafter. At no time, however, did the rate of carrier-mediated transport by embryonic erythrocytes differ significantly from that of the adult cells. The rate of transfer by simple diffusion was 3-5 fold faster in embryonic than in adult erythrocytes. Uptake by simple diffusion decreased slightly as the embryo developed. Chronic hyperoxic incubation (70% O2) had little influence on total monosaccharide uptake by embryonic erythrocytes.

Transgenerational Epigenetic Programming of the Embryonic Testis Transcriptome

PubMed Central

Anway, Matthew D.; Rekow, Stephen S.; Skinner, Michael K.

2008-01-01

Embryonic exposure to the endocrine disruptor vinclozolin during gonadal sex determination appears to promote an epigenetic reprogramming of the male germ-line that is associated with transgenerational adult onset disease states. Transgenerational effects on the embryonic day 16 (E16) testis demonstrated reproducible changes in the testis transcriptome for multiple generations (F1-F3). The expression of 196 genes were found to be influenced, with the majority of gene expression being decreased or silenced. Dramatic changes in the gene expression of methyltransferases during gonadal sex determination were observed in the F1 and F2 vinclozolin generation (E16) embryonic testis, but the majority returned to control generation levels by the F3 generation. The most dramatic effects were on the germ-line associated Dnmt3A and Dnmt3L isoforms. Observations demonstrate that an embryonic exposure to vinclozolin appears to promote an epigenetic reprogramming of the male germ-line that correlates with transgenerational alterations in the testis transcriptome in subsequent generations. PMID:18042343

Expression of zinc transporter ZnT7 in mouse superior cervical ganglion

USDA-ARS?s Scientific Manuscript database

The superior cervical ganglion (SCG) neurons contain a considerable amount of zinc ions, but little is known about zinc homeostasis in the SCG. It is known that zinc transporter 7 (ZnT7, Slc30a7), a member of the Slc30 ZnT family, is involved in mobilizing zinc ions from the cytoplasm into the Golgi...

[Decreased A-type potassium current mediates the hyperexcitability of nociceptive neurons in the chronically compressed dorsal root ganglia].

PubMed

Yan, Ni; Li, Xiao-Han; Cheng, Qi; Yan, Jin; Ni, Xin; Sun, Ji-Hu

2007-04-25

The excitability of nociceptive neurons increases in the intact dorsal root ganglion (DRG) after a chronic compression, but the underlying mechanisms are still unclear. The aim of this study was to investigate the ionic mechanisms underlying the hyperexcitability of nociceptive neurons in the compressed ganglion. Chronic compression of DRG (CCD) was produced in adult rats by inserting two rods through the intervertebral foramina to compress the L4 DRG and the ipsilateral L5 DRG. After 5-7 d, DRG somata were dissociated and placed in culture for 12-18 h. In sharp electrode recording model, the lower current threshold and the depolarized membrane potential in the acutely dissociated CCD neurons were detected, indicating that hyperexcitability is intrinsic to the soma. Since voltage-gated K(+) (Kv) channels in the primary sensory neurons are important for the regulation of excitability, we hypothesized that CCD would alter K(+) current properties in the primary sensory neurons. We examined the effects of 4-aminopyridine (4-AP), a specific antagonist of A-type potassium channel, on the excitability of the control DRG neurons. With 4-AP in the external solution, the control DRG neurons depolarized (with discharges in some cells) and their current threshold decreased as the CCD neurons demonstrated, indicating the involvement of decreased A-type potassium current in the hyperexcitability of the injured neurons. Furthermore, the alteration of A-type potassium current in nociceptive neurons in the compressed ganglion was investigated with the whole-cell patch-clamp recording model. CCD significantly decreased A-type potassium current density in nociceptive DRG neurons. These data suggest that a reduction in A-type potassium current contributes, at least in part, to the increase in neuron excitability that may lead to the development of pain and hyperalgesia associated with CCD.

Imprinted expression in cystic embryoid bodies shows an embryonic and not an extra-embryonic pattern

PubMed Central

Kulinski, Tomasz M.; Casari, M. Rita T.; Guenzl, Philipp M.; Wenzel, Daniel; Andergassen, Daniel; Hladik, Anastasiya; Datlinger, Paul; Farlik, Matthias; Theussl, H. -Christian; Penninger, Josef M.; Knapp, Sylvia; Bock, Christoph; Barlow, Denise P.; Hudson, Quanah J.

2015-01-01

A large subset of mammalian imprinted genes show extra-embryonic lineage (EXEL) specific imprinted expression that is restricted to placental trophectoderm lineages and to visceral yolk sac endoderm (ysE). Isolated ysE provides a homogenous in vivo model of a mid-gestation extra-embryonic tissue to examine the mechanism of EXEL-specific imprinted gene silencing, but an in vitro model of ysE to facilitate more rapid and cost-effective experiments is not available. Reports indicate that ES cells differentiated into cystic embryoid bodies (EBs) contain ysE, so here we investigate if cystic EBs model ysE imprinted expression. The imprinted expression pattern of cystic EBs is shown to resemble fetal liver and not ysE. To investigate the reason for this we characterized the methylome and transcriptome of cystic EBs in comparison to fetal liver and ysE, by whole genome bisulphite sequencing and RNA-seq. Cystic EBs show a fetal liver pattern of global hypermethylation and low expression of repeats, while ysE shows global hypomethylation and high expression of IAPEz retroviral repeats, as reported for placenta. Transcriptome analysis confirmed that cystic EBs are more similar to fetal liver than ysE and express markers of early embryonic endoderm. Genome-wide analysis shows that ysE shares epigenetic and repeat expression features with placenta. Contrary to previous reports, we show that cystic EBs do not contain ysE, but are more similar to the embryonic endoderm of fetal liver. This explains why cystic EBs reproduce the imprinted expression seen in the embryo but not that seen in the ysE. PMID:25912690

The root economics spectrum: divergence of absorptive root strategies with root diameter

NASA Astrophysics Data System (ADS)

Kong, D.; Wang, J.; Kardol, P.; Wu, H.; Zeng, H.; Deng, X.; Deng, Y.

2015-08-01

Plant roots usually vary along a dominant ecological axis, the root economics spectrum (RES), depicting a tradeoff between resource acquisition and conservation. For absorptive roots, which are mainly responsible for resource acquisition, we hypothesized that root strategies as predicted from the RES shift with increasing root diameter. To test this hypothesis, we used seven contrasting plant species for which we separated absorptive roots into two categories: thin roots (< 247 μm diameter) and thick roots. For each category, we analyzed a~range of root traits closely related to resource acquisition and conservation, including root tissue density, carbon (C) and nitrogen (N) fractions as well as root anatomical traits. The results showed that trait relationships for thin absorptive roots followed the expectations from the RES while no clear trait relationships were found in support of the RES for thick absorptive roots. Our results suggest divergence of absorptive root strategies in relation to root diameter, which runs against a single economics spectrum for absorptive roots.

First trimester size charts of embryonic brain structures.

PubMed

Gijtenbeek, M; Bogers, H; Groenenberg, I A L; Exalto, N; Willemsen, S P; Steegers, E A P; Eilers, P H C; Steegers-Theunissen, R P M

2014-02-01

Can reliable size charts of human embryonic brain structures be created from three-dimensional ultrasound (3D-US) visualizations? Reliable size charts of human embryonic brain structures can be created from high-quality images. Previous studies on the visualization of both the cavities and the walls of the brain compartments were performed using 2D-US, 3D-US or invasive intrauterine sonography. However, the walls of the diencephalon, mesencephalon and telencephalon have not been measured non-invasively before. Last-decade improvements in transvaginal ultrasound techniques allow a better visualization and offer the tools to measure these human embryonic brain structures with precision. This study is embedded in a prospective periconceptional cohort study. A total of 141 pregnancies were included before the sixth week of gestation and were monitored until delivery to assess complications and adverse outcomes. For the analysis of embryonic growth, 596 3D-US scans encompassing the entire embryo were obtained from 106 singleton non-malformed live birth pregnancies between 7(+0) and 12(+6) weeks' gestational age (GA). Using 4D View (3D software) the measured embryonic brain structures comprised thickness of the diencephalon, mesencephalon and telencephalon, and the total diameter of the diencephalon and mesencephalon. Of 596 3D scans, 161 (27%) high-quality scans of 79 pregnancies were eligible for analysis. The reliability of all embryonic brain structure measurements, based on the intra-class correlation coefficients (ICCs) (all above 0.98), was excellent. Bland-Altman plots showed moderate agreement for measurements of the telencephalon, but for all other measurements the agreement was good. Size charts were constructed according to crown-rump length (CRL). The percentage of high-quality scans suitable for analysis of these brain structures was low (27%).  The size charts of human embryonic brain structures can be used to study normal and abnormal development of

Functional Pattern of Increasing Concentrations of Brain-Derived Neurotrophic Factor in Spiral Ganglion: Implications for Research on Cochlear Implants.

PubMed

Ramku, Emina; Ramku, Refik; Spanca, Dugagjin; Zhjeqi, Valbona

2017-04-15

As previously various studies have suggested application of brain-derived neurotrophic factor (BDNF) may be considered as a promising future therapy for hearing deficits, in particular for the improvement of cochlear neurone loss during cochlear implantation. The present study's aim was to establish the upper threshold of the concentration of BDNF in Naval Medical Research Institute (NMRI) mice spiral ganglion outgrowth. Spiral ganglion explants were prepared from post-natal day 4 (p4) (NMRI) mice of both sexes under the approval and guidelines of the regional council of Hearing Research Institute Tubingen. Spiral ganglion explants were cultured at postnatal days 4 in the presence of different concentrations of BDNF as described under methods. We chose an age of postnatal day (P4) and concentrations of BDNF 0; 6; 12.5; 25 and 50 ƞg/ml. Averaged neurite outgrowth is measured in 4 different cultures that were treated with different concentrations. Results show that with increasing concentrations of BDNF, the neurite density increases. The present finding show evidence that BDNF has a clear incremental effect on the number of neurites of spiral ganglia in the prehearing organ, but less on the neurite length. The upper threshold of exogenous BNDF concentration on spiral ganglion explant is 25 ƞg/ml. This means that concentration beyond this level has no further incremental impact. Therefore our suggestion for hydrogel concentration in NMRA mice in future research should be 25 ƞg/ml.

Expression and Function of System N Glutamine Transporters (SN1/SN2 or SNAT3/SNAT5) in Retinal Ganglion Cells

PubMed Central

Umapathy, Nagavedi S.; Dun, Ying; Martin, Pamela M.; Duplantier, Jennifer N.; Roon, Penny; Prasad, Puttur; Smith, Sylvia B.; Ganapathy, Vadivel

2008-01-01

Purpose Glutamine transport is essential for the glutamate-glutamine cycle, which occurs between neurons and glia. System N, consisting of SN1 (SNAT3) and SN2 (SNAT5), is the principal mediator of glutamine transport in retinal Müller cells. Mediators of glutamine transport in retinal ganglion cells were investigated. Methods The relative contributions of various transport systems for glutamine uptake (systems N, A, L, y+L, ASCT, and ATB0,+) were examined in RGC-5 cells based on differential features of the individual transport systems. mRNA for the genes encoding members of these transport systems were analyzed by RT-PCR. Based on these data, SN1 and SN2 were analyzed in mouse retina, RGC-5 cells, and primary mouse ganglion cells (GCs) by in situ hybridization (ISH), immunofluorescence (IF), and Western blotting. Results Three transport systems—N, A, and L—participated in glutamine uptake in RGC-5 cells. System N was the principal contributor; systems A and L contributed considerably less. ISH and IF revealed SN1 and SN2 expression in the ganglion, inner nuclear, and photoreceptor cell layers. SN1 and SN2 colocalized with the ganglion cell marker Thy 1.2 and with the Müller cell marker vimentin, confirming their presence in both retinal cell types. SN1 and SN2 proteins were detected in primary mouse GCs. Conclusions These findings suggest that in addition to its role in glutamine uptake in retinal glial cells, system N contributes significantly to glutamine uptake in ganglion cells and, hence, contributes to the retinal glutamate-glutamine cycle. PMID:18689705

Relationships between root diameter, root length and root branching along lateral roots in adult, field-grown maize

PubMed Central

Wu, Qian; Pagès, Loïc; Wu, Jie

2016-01-01

Background and Aims Root diameter, especially apical diameter, plays an important role in root development and function. The variation in diameter between roots, and along roots, affects root structure and thus the root system’s overall foraging performance. However, the effect of diameter variation on root elongation, branching and topological connections has not been examined systematically in a population of high-order roots, nor along the roots, especially for mature plants grown in the field. Methods A method combining both excavation and analysis was applied to extract and quantify root architectural traits of adult, field-grown maize plants. The relationships between root diameter and other root architectural characteristics are analysed for two maize cultivars. Key Results The basal diameter of the lateral roots (orders 1–3) was highly variable. Basal diameter was partly determined by the diameter of the bearing segment. Basal diameter defined a potential root length, but the lengths of most roots fell far short of this. This was explained partly by differences in the pattern of diameter change along roots. Diameter tended to decrease along most roots, with the steepness of the gradient of decrease depending on basal diameter. The longest roots were those that maintained (or sometimes increased) their diameters during elongation. The branching density (cm–1) of laterals was also determined by the diameter of the bearing segment. However, the location of this bearing segment along the mother root was also involved – intermediate positions were associated with higher densities of laterals. Conclusions The method used here allows us to obtain very detailed records of the geometry and topology of a complex root system. Basal diameter and the pattern of diameter change along a root were associated with its final length. These relationships are especially useful in simulations of root elongation and branching in source–sink models. PMID:26744490

The Three-Dimensional Culture System with Matrigel and Neurotrophic Factors Preserves the Structure and Function of Spiral Ganglion Neuron In Vitro.

PubMed

Sun, Gaoying; Liu, Wenwen; Fan, Zhaomin; Zhang, Daogong; Han, Yuechen; Xu, Lei; Qi, Jieyu; Zhang, Shasha; Gao, Bradley T; Bai, Xiaohui; Li, Jianfeng; Chai, Renjie; Wang, Haibo

2016-01-01

Whole organ culture of the spiral ganglion region is a resourceful model system facilitating manipulation and analysis of live sprial ganglion neurons (SGNs). Three-dimensional (3D) cultures have been demonstrated to have many biomedical applications, but the effect of 3D culture in maintaining the SGNs structure and function in explant culture remains uninvestigated. In this study, we used the matrigel to encapsulate the spiral ganglion region isolated from neonatal mice. First, we optimized the matrigel concentration for the 3D culture system and found the 3D culture system protected the SGNs against apoptosis, preserved the structure of spiral ganglion region, and promoted the sprouting and outgrowth of SGNs neurites. Next, we found the 3D culture system promoted growth cone growth as evidenced by a higher average number and a longer average length of filopodia and a larger growth cone area. 3D culture system also significantly elevated the synapse density of SGNs. Last, we found that the 3D culture system combined with neurotrophic factors had accumulated effects in promoting the neurites outgrowth compared with 3D culture or NFs treatment only groups. Together, we conclude that the 3D culture system preserves the structure and function of SGN in explant culture.

Diverging functions of Scr between embryonic and post-embryonic development in a hemimetabolous insect, Oncopeltus fasciatus.

PubMed

Chesebro, John; Hrycaj, Steven; Mahfooz, Najmus; Popadić, Aleksandar

2009-05-01

Hemimetabolous insects undergo an ancestral mode of development in which embryos hatch into first nymphs that resemble miniature adults. While recent studies have shown that homeotic (hox) genes establish segmental identity of first nymphs during embryogenesis, no information exists on the function of these genes during post-embryogenesis. To determine whether and to what degree hox genes influence the formation of adult morphologies, we performed a functional analysis of Sex combs reduced (Scr) during post-embryonic development in Oncopeltus fasciatus. The main effect was observed in prothorax of Scr-RNAi adults, and ranged from significant alterations in its size and shape to a near complete transformation of its posterior half toward a T2-like identity. Furthermore, while the consecutive application of Scr-RNAi at both of the final two post-embryonic stages (fourth and fifth) did result in formation of ectopic wings on T1, the individual applications at each of these stages did not. These experiments provide two new insights into evolution of wings. First, the role of Scr in wing repression appears to be conserved in both holo- and hemimetabolous insects. Second, the prolonged Scr-depletion (spanning at least two nymphal stages) is both necessary and sufficient to restart wing program. At the same time, other structures that were previously established during embryogenesis are either unaffected (T1 legs) or display only minor changes (labium) in adults. These observations reveal a temporal and spatial divergence of Scr roles during embryonic (main effect in labium) and post-embryonic (main effect in prothorax) development.

Diverging functions of Scr between embryonic and post-embryonic development in a hemimetabolous insect, Oncopeltus fasciatus

PubMed Central

Chesebro, John; Hrycaj, Steven; Mahfooz, Najmus; Popadić, Aleksandar

2009-01-01

Hemimetabolous insects undergo an ancestral mode of development in which embryos hatch into first nymphs that resemble miniature adults. While recent studies have shown that homeotic (hox) genes establish segmental identity of first nymphs during embryogenesis, no information exists on the function of these genes during post-embryogenesis. To determine whether and to what degree hox genes influence the formation of adult morphologies, we performed a functional analysis of Sex combs reduced (Scr) during post-embryonic development in Oncopeltus fasciatus. The main effect was observed in prothorax of Scr-RNAi adults, and ranged from significant alterations in its size and shape to a near complete transformation of its posterior half toward a T2-like identity. Furthermore, while the consecutive application of Scr-RNAi at both of the final two post-embryonic stages (fourth and fifth) did result in formation of ectopic wings on T1, the individual applications at each of these stages did not. These experiments provide two new insights into evolution of wings. First, the role of Scr in wing repression appears to be conserved in both holo- and hemimetabolous insects. Second, the prolonged Scr-depletion (spanning at least two nymphal stages) is both necessary and sufficient to restart wing program. At the same time, other structures that were previously established during embryogenesis are either unaffected (T1 legs) or display only minor changes (labium) in adults. These observations reveal a temporal and spatial divergence of Scr roles during embryonic (main effect in labium) and post-embryonic (main effect in prothorax) development. PMID:19382295

Calcium Signaling in Intact Dorsal Root Ganglia

PubMed Central

Gemes, Geza; Rigaud, Marcel; Koopmeiners, Andrew S.; Poroli, Mark J.; Zoga, Vasiliki; Hogan, Quinn H.

2013-01-01

Background Ca2+ is the dominant second messenger in primary sensory neurons. In addition, disrupted Ca2+ signaling is a prominent feature in pain models involving peripheral nerve injury. Standard cytoplasmic Ca2+ recording techniques use high K+ or field stimulation and dissociated neurons. To compare findings in intact dorsal root ganglia, we used a method of simultaneous electrophysiologic and microfluorimetric recording. Methods Dissociated neurons were loaded by bath-applied Fura-2-AM and subjected to field stimulation. Alternatively, we adapted a technique in which neuronal somata of intact ganglia were loaded with Fura-2 through an intracellular microelectrode that provided simultaneous membrane potential recording during activation by action potentials (APs) conducted from attached dorsal roots. Results Field stimulation at levels necessary to activate neurons generated bath pH changes through electrolysis and failed to predictably drive neurons with AP trains. In the intact ganglion technique, single APs produced measurable Ca2+ transients that were fourfold larger in presumed nociceptive C-type neurons than in nonnociceptive Aβ-type neurons. Unitary Ca2+ transients summated during AP trains, forming transients with amplitudes that were highly dependent on stimulation frequency. Each neuron was tuned to a preferred frequency at which transient amplitude was maximal. Transients predominantly exhibited monoexponential recovery and had sustained plateaus during recovery only with trains of more than 100 APs. Nerve injury decreased Ca2+ transients in C-type neurons, but increased transients in Aβ-type neurons. Conclusions Refined observation of Ca2+ signaling is possible through natural activation by conducted APs in undissociated sensory neurons and reveals features distinct to neuronal types and injury state. PMID:20526180

In vivo fluorescence imaging of primate retinal ganglion cells and retinal pigment epithelial cells

NASA Astrophysics Data System (ADS)

Gray, Daniel C.; Merigan, William; Wolfing, Jessica I.; Gee, Bernard P.; Porter, Jason; Dubra, Alfredo; Twietmeyer, Ted H.; Ahamd, Kamran; Tumbar, Remy; Reinholz, Fred; Williams, David R.

2006-08-01

The ability to resolve single cells noninvasively in the living retina has important applications for the study of normal retina, diseased retina, and the efficacy of therapies for retinal disease. We describe a new instrument for high-resolution, in vivo imaging of the mammalian retina that combines the benefits of confocal detection, adaptive optics, multispectral, and fluorescence imaging. The instrument is capable of imaging single ganglion cells and their axons through retrograde transport in ganglion cells of fluorescent dyes injected into the monkey lateral geniculate nucleus (LGN). In addition, we demonstrate a method involving simultaneous imaging in two spectral bands that allows the integration of very weak signals across many frames despite inter-frame movement of the eye. With this method, we are also able to resolve the smallest retinal capillaries in fluorescein angiography and the mosaic of retinal pigment epithelium (RPE) cells with lipofuscin autofluorescence.

Combined application of BDNF to the eye and brain enhances ganglion cell survival and function in the cat after optic nerve injury.

PubMed

Weber, Arthur J; Viswanáthan, Suresh; Ramanathan, Chidambaram; Harman, Christine D

2010-01-01

To determine whether application of BDNF to the eye and brain provides a greater level of neuroprotection after optic nerve injury than treatment of the eye alone. Retinal ganglion cell survival and pattern electroretinographic responses were compared in normal cat eyes and in eyes that received (1) a mild nerve crush and no treatment, (2) a single intravitreal injection of BDNF at the time of the nerve injury, or (3) intravitreal treatment combined with 1 to 2 weeks of continuous delivery of BDNF to the visual cortex, bilaterally. Relative to no treatment, administration of BDNF to the eye alone resulted in a significant increase in ganglion cell survival at both 1 and 2 weeks after nerve crush (1 week, 79% vs. 55%; 2 weeks, 60% vs. 31%). Combined treatment of the eye and visual cortex resulted in a modest additional increase (17%) in ganglion cell survival in the 1-week eyes, a further significant increase (55%) in the 2-week eyes, and ganglion cell survival levels for both that were comparable to normal (92%-93% survival). Pattern ERG responses for all the treated eyes were comparable to normal at 1 week after injury; however, at 2 weeks, only the responses of eyes receiving the combined BDNF treatment remained so. Although treatment of the eye alone with BDNF has a significant impact on ganglion cell survival after optic nerve injury, combined treatment of the eye and brain may represent an even more effective approach and should be considered in the development of future optic neuropathy-related neuroprotection strategies.

Childhood Central Nervous System Embryonal Tumors (PDQ®)—Health Professional Version

Cancer.gov

Pediatric CNS embryonal tumors are a collection of heterogeneous lesions (medulloblastoma, and nonmedulloblastoma). Molecular genetic studies are used to classify embryonal tumors, stratify risk, and plan treatment. Get detailed information about tumor biology, diagnosis, prognosis, and treatment of untreated and recurrent CNS embryonal tumors in this summary for clinicians.

Organ of Corti explants direct tonotopically graded morphology of spiral ganglion neurons in vitro.

PubMed

Smith, Felicia L; Davis, Robin L

2016-08-01

The spiral ganglion is a compelling model system to examine how morphological form contributes to sensory function. While the ganglion is composed mainly of a single class of type I neurons that make simple one-to-one connections with inner hair cell sensory receptors, it has an elaborate overall morphological design. Specific features, such as soma size and axon outgrowth, are graded along the spiral contour of the cochlea. To begin to understand the interplay between different regulators of neuronal morphology, we cocultured neuron explants with peripheral target tissues removed from distinct cochlear locations. Interestingly, these "hair cell microisolates" were capable of both increasing and decreasing neuronal somata size, without adversely affecting survival. Moreover, axon characteristics elaborated de novo by the primary afferents in culture were systematically regulated by the sensory endorgan. Apparent peripheral nervous system (PNS)-like and central nervous system (CNS)-like axonal profiles were established in our cocultures allowing an analysis of putative PNS/CNS axon length ratios. As predicted from the in vivo organization, PNS-like axon bundles elaborated by apical cocultures were longer than their basal counterparts and this phenotype was methodically altered when neuron explants were cocultured with microisolates from disparate cochlear regions. Thus, location-dependent signals within the organ of Corti may set the "address" of neurons within the spiral ganglion, allowing them to elaborate the appropriate tonotopically associated morphological features in order to carry out their signaling function. J. Comp. Neurol. 524:2182-2207, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Macular ganglion cell imaging study: glaucoma diagnostic accuracy of spectral-domain optical coherence tomography.

PubMed

Jeoung, Jin Wook; Choi, Yun Jeong; Park, Ki Ho; Kim, Dong Myung

2013-07-01

We evaluated the diagnostic accuracy of macular ganglion cell-inner plexiform layer (GCIPL) measurements using a high-definition optical coherence tomography (Cirrus HD-OCT) ganglion cell analysis algorithm for detecting early and moderate-to-severe glaucoma. Totals of 119 normal subjects and 306 glaucoma patients (164 patients with early glaucoma and 142 with moderate-to-severe glaucoma) were enrolled from the Macular Ganglion Cell Imaging Study. Macular GCIPL, peripapillary retinal nerve fiber layer (RNFL) thickness, and optic nerve head (ONH) parameters were measured in each subject. Areas under the receiver operating characteristic curves (AUROCs) were calculated and compared. Based on the internal normative database, the sensitivity and specificity for detecting early and moderate-to-severe glaucoma were calculated. There was no statistically significant difference between the AUROCs for the best OCT parameters. For detecting early glaucoma, the sensitivity of the Cirrus GCIPL parameters ranged from 26.8% to 73.2% and that of the Cirrus RNFL parameters ranged from 6.1% to 61.6%. For the early glaucoma group, the best parameter from the GCIPL generally had a higher sensitivity than those of the RNFL and ONH parameters with comparable specificity (P < 0.05, McNemar's test). There were no significant differences between the AUROCs for Cirrus GCIPL, RNFL, and ONH parameters, indicating that these maps have similar diagnostic potentials for glaucoma. The minimum GCIPL showed better glaucoma diagnostic performance than the other parameters at comparable specificities. However, other GCIPL parameters showed performances comparable to those of the RNFL parameters.

Separability of stimulus parameter encoding by on-off directionally selective rabbit retinal ganglion cells

PubMed Central

Nowak, Przemyslaw; Dobbins, Allan C.; Gawne, Timothy J.; Grzywacz, Norberto M.

2011-01-01

The ganglion cell output of the retina constitutes a bottleneck in sensory processing in that ganglion cells must encode multiple stimulus parameters in their responses. Here we investigate encoding strategies of On-Off directionally selective retinal ganglion cells (On-Off DS RGCs) in rabbits, a class of cells dedicated to representing motion. The exquisite axial discrimination of these cells to preferred vs. null direction motion is well documented: it is invariant with respect to speed, contrast, spatial configuration, spatial frequency, and motion extent. However, these cells have broad direction tuning curves and their responses also vary as a function of other parameters such as speed and contrast. In this study, we examined whether the variation in responses across multiple stimulus parameters is systematic, that is the same for all cells, and separable, such that the response to a stimulus is a product of the effects of each stimulus parameter alone. We extracellularly recorded single On-Off DS RGCs in a superfused eyecup preparation while stimulating them with moving bars. We found that spike count responses of these cells scaled as independent functions of direction, speed, and luminance. Moreover, the speed and luminance functions were common across the whole sample of cells. Based on these findings, we developed a model that accurately predicted responses of On-Off DS RGCs as products of separable functions of direction, speed, and luminance (r = 0.98; P < 0.0001). Such a multiplicatively separable encoding strategy may simplify the decoding of these cells' outputs by the higher visual centers. PMID:21325684

Influence of needle position on lumbar segmental nerve root block selectivity.

PubMed

Wolff, André P; Groen, Gerbrand J; Wilder-Smith, Oliver H

2006-01-01

In patients with chronic low back pain radiating to the leg, segmental nerve root blocks (SNRBs) are performed to predict surgical outcome and identify the putative symptomatic spinal nerve. Epidural spread may lead to false interpretation, affecting clinical decision making. Systematic fluoroscopic analysis of epidural local anesthetic spread and its relationship to needle tip location has not been published to date. Study aims include assessment of epidural local anesthetic spread and its relationship to needle position during fluoroscopy-assisted blocks. Patients scheduled for L4, L5, and S1 blocks were included in this prospective observational study. Under fluoroscopy and electrostimulation, they received 0.5 mL of a mixture containing lidocaine 5 mg and iohexol 75 mg. X-rays with needle tip and contrast were scored for no epidural spread (grade 0), local spread epidurally (grade 1), or to adjacent nerve roots (grade 2). Sixty-five patients were analyzed for epidural spread, 62 for needle position. Grade 1 epidural spread occurred in 47% of L4 and 28% of L5 blocks and grade 2 spread in 3 blocks (5%; L5 n = 1, S1 n = 2). For lumbar blocks, the needle was most frequently found in the lateral upper half of the intervertebral foramen. Epidural spread occurred more frequently with medial needle positions (P = .06). The findings suggest (P = .06) that the risk of grade 1 and 2 lumbar epidural spread, which results in decreased SNRB selectivity, is greater with medial needle positions in the intervertebral foramen. The variability in anatomic position of the dorsal root ganglion necessitates electrostimulation to guide SNRB in addition to fluoroscopy.

Role of motor-evoked potential monitoring in conjunction with temporary clipping of spinal nerve roots in posterior thoracic spine tumor surgery.

PubMed

Eleraky, Mohammed A; Setzer, Matthias; Papanastassiou, Ioannis D; Baaj, Ali A; Tran, Nam D; Katsares, Kiesha M; Vrionis, Frank D

2010-05-01

The vascular supply of the thoracic spinal cord depends on the thoracolumbar segmental arteries. Because of the small size and ventral course of these arteries in relation to the dorsal root ganglion and ventral root, they cannot be reliably identified during surgery by anatomic or morphologic criteria. Sacrificing them will most likely result in paraplegia. The goal of this study was to evaluate a novel method of intraoperative testing of a nerve root's contribution to the blood supply of the thoracic spinal cord. This is a clinical retrospective study of 49 patients diagnosed with thoracic spine tumors. Temporary nerve root clipping combined with motor-evoked potential (MEP) and somatosensory-evoked potential (SSEP) monitoring was performed; additionally, postoperative clinical evaluation was done and reported in all cases. All cases were monitored by SSEP and MEPs. The nerve root to be sacrificed was temporarily clipped using standard aneurysm clips, and SSEP/MEP were assessed before and after clipping. Four nerve roots were sacrificed in four cases, three nerve roots in eight cases, and two nerve roots in 22 cases. Nerve roots were sacrificed bilaterally in 12 cases. Most patients (47/49) had no changes in MEP/SSEP and had no neurological deficit postoperatively. One case of a spinal sarcoma demonstrated changes in MEP after temporary clipping of the left T11 nerve root. The nerve was not sacrificed, and the patient was neurologically intact after surgery. In another case of a sarcoma, MEPs changed in the lower limbs after ligation of left T9 nerve root. It was felt that it was a global event because of anesthesia. Postoperatively, the patient had complete paraplegia but recovered almost completely after 6 months. Temporary nerve root clipping combined with MEP and SSEP monitoring may enhance the impact of neuromonitoring in the intraoperative management of patients with thoracic spine tumors and favorably influence neurological outcome. Copyright 2010 Elsevier

Flt1/VEGFR1 heterozygosity causes transient embryonic edema.

PubMed

Otowa, Yasunori; Moriwaki, Kazumasa; Sano, Keigo; Shirakabe, Masanori; Yonemura, Shigenobu; Shibuya, Masabumi; Rossant, Janet; Suda, Toshio; Kakeji, Yoshihiro; Hirashima, Masanori

2016-06-02

Vascular endothelial growth factor-A is a major player in vascular development and a potent vascular permeability factor under physiological and pathological conditions by binding to a decoy receptor Flt1 and its primary receptor Flk1. In this study, we show that Flt1 heterozygous (Flt1(+/-)) mouse embryos grow up to adult without life-threatening abnormalities but exhibit a transient embryonic edema around the nuchal and back regions, which is reminiscent of increased nuchal translucency in human fetuses. Vascular permeability is enhanced and an intricate infolding of the plasma membrane and huge vesicle-like structures are seen in Flt1(+/-) capillary endothelial cells. Flk1 tyrosine phosphorylation is elevated in Flt1(+/-) embryos, but Flk1 heterozygosity does not suppress embryonic edema caused by Flt1 heterozygosity. When Flt1 mutants are crossed with Aspp1(-/-) mice which exhibit a transient embryonic edema with delayed formation and dysfunction of lymphatic vessels, only 5.7% of Flt1(+/-); Aspp1(-/-) mice survive, compared to expected ratio (25%). Our results demonstrate that Flt1 heterozygosity causes a transient embryonic edema and can be a risk factor for embryonic lethality in combination with other mutations causing non-lethal vascular phenotype.

Extra-embryonic tissue spreading directs early embryo morphogenesis in killifish

PubMed Central

Reig, Germán; Cerda, Mauricio; Sepúlveda, Néstor; Flores, Daniela; Castañeda, Victor; Tada, Masazumi; Härtel, Steffen; Concha, Miguel L.

2017-01-01

The spreading of mesenchymal-like cell layers is critical for embryo morphogenesis and tissue repair, yet we know little of this process in vivo. Here we take advantage of unique developmental features of the non-conventional annual killifish embryo to study the principles underlying tissue spreading in a simple cellular environment, devoid of patterning signals and major morphogenetic cell movements. Using in vivo experimentation and physical modelling we reveal that the extra-embryonic epithelial enveloping cell layer, thought mainly to provide protection to the embryo, directs cell migration and the spreading of embryonic tissue during early development. This function relies on the ability of embryonic cells to couple their autonomous random motility to non-autonomous signals arising from the expansion of the extra-embryonic epithelium, mediated by cell membrane adhesion and tension. Thus, we present a mechanism of extra-embryonic control of embryo morphogenesis that couples the mechanical properties of adjacent tissues in the early killifish embryo. PMID:28580937

Automated Root Tracking with "Root System Analyzer"

NASA Astrophysics Data System (ADS)

Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

2015-04-01

Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

Petrosal ganglion: a more complex role than originally imagined.

PubMed

Retamal, Mauricio A; Reyes, Edison P; Alcayaga, Julio

2014-01-01

The petrosal ganglion (PG) is a peripheral sensory ganglion, composed of pseudomonopolar sensory neurons that innervate the posterior third of the tongue and the carotid sinus and body. According to their electrical properties PG neurons can be ascribed to one of two categories: (i) neurons with action potentials presenting an inflection (hump) on its repolarizing phase and (ii) neurons with fast and brisk action potentials. Although there is some correlation between the electrophysiological properties and the sensory modality of the neurons in some species, no general pattern can be easily recognized. On the other hand, petrosal neurons projecting to the carotid body are activated by several transmitters, with acetylcholine and ATP being the most conspicuous in most species. Petrosal neurons are completely surrounded by a multi-cellular sheet of glial (satellite) cells that prevents the formation of chemical or electrical synapses between neurons. Thus, PG neurons are regarded as mere wires that communicate the periphery (i.e., carotid body) and the central nervous system. However, it has been shown that in other sensory ganglia satellite glial cells and their neighboring neurons can interact, partly by the release of chemical neuro-glio transmitters. This intercellular communication can potentially modulate the excitatory status of sensory neurons and thus the afferent discharge. In this mini review, we will briefly summarize the general properties of PG neurons and the current knowledge about the glial-neuron communication in sensory neurons and how this phenomenon could be important in the chemical sensory processing generated in the carotid body.

Derivation of Multipotent Mesenchymal Precursors from Human Embryonic Stem Cells

PubMed Central

Barberi, Tiziano; Willis, Lucy M; Socci, Nicholas D; Studer, Lorenz

2005-01-01

Background Human embryonic stem cells provide access to the earliest stages of human development and may serve as a source of specialized cells for regenerative medicine. Thus, it becomes crucial to develop protocols for the directed differentiation of embryonic stem cells into tissue-restricted precursors. Methods and Findings Here, we present culture conditions for the derivation of unlimited numbers of pure mesenchymal precursors from human embryonic stem cells and demonstrate multilineage differentiation into fat, cartilage, bone, and skeletal muscle cells. Conclusion Our findings will help to elucidate the mechanism of mesoderm specification during embryonic stem cell differentiation and provide a platform to efficiently generate specialized human mesenchymal cell types for future clinical applications. PMID:15971941

Suprascapular Nerve Entrapment Caused by Protrusion of an Intraosseous Ganglion of the Glenoid into the Spinoglenoid Notch: A Rare Cause of Posterior Shoulder Pain

PubMed Central

Terabayashi, Nobuo; Nishimoto, Yutaka; Akiyama, Haruhiko

2017-01-01

We describe a case of suprascapular nerve entrapment caused by protrusion of an intraosseous ganglion of the glenoid into the spinoglenoid notch. A 47-year-old man with left shoulder pain developed an intraosseous cyst in the left glenoid, which came into contact with the suprascapular nerve. The area at which the patient experienced spontaneous shoulder pain was innervated by the suprascapular nerve, and 1% xylocaine injection into the spinoglenoid notch under ultrasonographic guidance relieved the pain. Therefore, we concluded that the protrusion of an intraosseous cyst of the glenoid into the spinoglenoid notch was a cause of the pain, and performed curettage. Consequently, the shoulder pain was resolved promptly without suprascapular nerve complications, and the cyst was histologically diagnosed as an intraosseous ganglion. This case demonstrated that the intraosseous ganglion of the glenoid was a benign lesion but could be a cause of suprascapular nerve entrapment syndrome. Curettage is a useful treatment option for a ganglion inside bone and very close to the suprascapular nerve. PMID:28620557

Unmasking of spiral ganglion neuron firing dynamics by membrane potential and neurotrophin-3.

PubMed

Crozier, Robert A; Davis, Robin L

2014-07-16

Type I spiral ganglion neurons have a unique role relative to other sensory afferents because, as a single population, they must convey the richness, complexity, and precision of auditory information as they shape signals transmitted to the brain. To understand better the sophistication of spiral ganglion response properties, we compared somatic whole-cell current-clamp recordings from basal and apical neurons obtained during the first 2 postnatal weeks from CBA/CaJ mice. We found that during this developmental time period neuron response properties changed from uniformly excitable to differentially plastic. Low-frequency, apical and high-frequency basal neurons at postnatal day 1 (P1)-P3 were predominantly slowly accommodating (SA), firing at low thresholds with little alteration in accommodation response mode induced by changes in resting membrane potential (RMP) or added neurotrophin-3 (NT-3). In contrast, P10-P14 apical and basal neurons were predominately rapidly accommodating (RA), had higher firing thresholds, and responded to elevation of RMP and added NT-3 by transitioning to the SA category without affecting the instantaneous firing rate. Therefore, older neurons appeared to be uniformly less excitable under baseline conditions yet displayed a previously unrecognized capacity to change response modes dynamically within a remarkably stable accommodation framework. Because the soma is interposed in the signal conduction pathway, these specializations can potentially lead to shaping and filtering of the transmitted signal. These results suggest that spiral ganglion neurons possess electrophysiological mechanisms that enable them to adapt their response properties to the characteristics of incoming stimuli and thus have the capacity to encode a wide spectrum of auditory information. Copyright © 2014 the authors 0270-6474/14/349688-15$15.00/0.

An endogenous capsaicin-like substance with high potency at recombinant and native vanilloid VR1 receptors

PubMed Central

Huang, Susan M.; Bisogno, Tiziana; Trevisani, Marcello; Al-Hayani, Abdulmonem; De Petrocellis, Luciano; Fezza, Filomena; Tognetto, Michele; Petros, Timothy J.; Krey, Jocelyn F.; Chu, Constance J.; Miller, Jeffrey D.; Davies, Stephen N.; Geppetti, Pierangelo; Walker, J. Michael; Di Marzo, Vincenzo

2002-01-01

The vanilloid receptor VR1 is a nonselective cation channel that is most abundant in peripheral sensory fibers but also is found in several brain nuclei. VR1 is gated by protons, heat, and the pungent ingredient of “hot” chili peppers, capsaicin. To date, no endogenous compound with potency at this receptor comparable to that of capsaicin has been identified. Here we examined the hypothesis, based on previous structure-activity relationship studies and the availability of biosynthetic precursors, that N-arachidonoyl-dopamine (NADA) is an endogenous “capsaicin-like” substance in mammalian nervous tissues. We found that NADA occurs in nervous tissues, with the highest concentrations being found in the striatum, hippocampus, and cerebellum and the lowest concentrations in the dorsal root ganglion. We also gained evidence for the existence of two possible routes for NADA biosynthesis and mechanisms for its inactivation in rat brain. NADA activates both human and rat VR1 overexpressed in human embryonic kidney (HEK)293 cells, with potency (EC50 ≈ 50 nM) and efficacy similar to those of capsaicin. Furthermore, NADA potently activates native vanilloid receptors in neurons from rat dorsal root ganglion and hippocampus, thereby inducing the release of substance P and calcitonin gene-related peptide (CGRP) from dorsal spinal cord slices and enhancing hippocampal paired-pulse depression, respectively. Intradermal NADA also induces VR1-mediated thermal hyperalgesia (EC50 = 1.5 ± 0.3 μg). Our data demonstrate the existence of a brain substance similar to capsaicin not only with respect to its chemical structure but also to its potency at VR1 receptors. PMID:12060783

Neurogenin 1 Null Mutant Ears Develop Fewer, Morphologically Normal Hair Cells in Smaller Sensory Epithelia Devoid of Innervation

PubMed Central

Ma, Qiufu; Anderson, David J.

2000-01-01

The proneuronal gene neurogenin 1 (ngn1) is essential for development of the inner-ear sensory neurons that are completely absent in ngn1 null mutants. Neither afferent, efferent, nor autonomic nerve fibers were detected in the ears of ngn1 null mutants. We suggest that efferent and autonomic fibers are lost secondarily to the absence of afferents. In this article we show that ngn1 null mutants develop smaller sensory epithelia with morphologically normal hair cells. In particular, the saccule is reduced dramatically and forms only a small recess with few hair cells along a duct connecting the utricle with the cochlea. Hair cells of newborn ngn1 null mutants show no structural abnormalities, suggesting that embryonic development of hair cells is independent of innervation. However, the less regular pattern of dispersal within sensory epithelia may be caused by some effects of afferents or to the stunted growth of the sensory epithelia. Tracing of facial and stato-acoustic nerves in control and ngn1 null mutants showed that only the distal, epibranchial, placode-derived sensory neurons of the geniculate ganglion exist in mutants. Tracing further showed that these geniculate ganglion neurons project exclusively to the solitary tract. In addition to the normal complement of facial branchial and visceral motoneurons, ngn1 null mutants have some trigeminal motoneurons and contralateral inner-ear efferents projecting, at least temporarily, through the facial nerve. These data suggest that some neurons in the brainstem (e.g., inner-ear efferents, trigeminal motoneurons) require afferents to grow along and redirect to ectopic cranial nerve roots in the absence of their corresponding sensory roots. PMID:11545141

Tumor necrosis factor-α stimulation of calcitonin gene-related peptide expression and secretion from rat trigeminal ganglion neurons

PubMed Central

Bowen, Elizabeth J.; Schmidt, Thomas W.; Firm, Christina S.; Russo, Andrew F.; Durham, Paul L.

2006-01-01

Expression of the neuropeptide calcitonin gene-related peptide (CGRP) in trigeminal ganglion is implicated in neurovascular headaches and temporomandibular joint disorders. Elevation of cytokines contributes to the pathology of these diseases. However, a connection between cytokines and CGRP gene expression in trigeminal ganglion nerves has not been established. We have focused on the effects of the cytokine tumor necrosis factorα (TNFα). TNFR1 receptors were found on the majority of CGRP-containing rat trigeminal ganglion neurons. Treatment of cultures with TNFα stimulated CGRP secretion. In addition, the intracellular signaling intermediate from the TNFR1 receptor, ceramide, caused a similar increase in CGRP release. TNFα caused a coordinate increase in CGRP promoter activity. TNFα treatment activated the transcription factor NF-κB, as well as the Jun N-terminal kinase (JNK) and p38 mitogen-activated protein (MAP) kinase pathways. The importance of TNFα induction of MAP kinase pathways was demonstrated by inhibiting MAP kinases with pharmacological reagents and gene transfer with an adenoviral vector encoding MAP kinase phosphatase-1 (MKP-1). We propose that selective and regulated inhibition of MAP kinases in trigeminal neurons may be therapeutically beneficial for inflammatory disorders involving elevated CGRP levels. PMID:16277606

Ganglion cyst arising from the composite occipito-atlanto-axial joint cavity in a cat.

PubMed

Aikawa, T; Sadahiro, S; Nishimura, M; Miyazaki, Y; Shibata, M

2014-01-01

A four-year-old, female spayed Domestic Longhaired cat was referred for evaluation with a two month history of initial inability to jump progressing to ambulatory tetraparesis. Magnetic resonance imaging studies demonstrated a cystic lesion arising from the composite occipito-atlanto-axial joint cavity and extending to the region of the occipital bone and the axis. The lesion surrounded the spinal canal, causing moderate dorsal spinal cord compression at the atlanto-occipital joint. A dynamic myelographic study demonstrated attenuation of the dorsal contrast column at the atlanto-occipital joint when the cervical spine was positioned in extension. Partial excision of the cyst capsule by a ventral approach resulted in long-term (64 months) resolution of clinical signs. Histological evaluation was consistent with a ganglion cyst. An intra-spinal ganglion cyst arising from the composite occipito-atlanto-axial joint cavity may be considered as an uncommon differential diagnosis for cats with cervical myelopathy.

Delayed-rectifier K channels contribute to contrast adaptation in mammalian retinal ganglion cells.

PubMed

Weick, Michael; Demb, Jonathan B

2011-07-14

Retinal ganglion cells adapt by reducing their sensitivity during periods of high contrast. Contrast adaptation in the firing response depends on both presynaptic and intrinsic mechanisms. Here, we investigated intrinsic mechanisms for contrast adaptation in OFF Alpha ganglion cells in the in vitro guinea pig retina. Using either visual stimulation or current injection, we show that brief depolarization evoked spiking and suppressed firing during subsequent depolarization. The suppression could be explained by Na channel inactivation, as shown in salamander cells. However, brief hyperpolarization in the physiological range (5-10 mV) also suppressed firing during subsequent depolarization. This suppression was selectively sensitive to blockers of delayed-rectifier K channels (K(DR)). In somatic membrane patches, we observed tetraethylammonium-sensitive K(DR) currents that activated near -25 mV. Recovery from inactivation occurred at potentials hyperpolarized to V(rest). Brief periods of hyperpolarization apparently remove K(DR) inactivation and thereby increase the channel pool available to suppress excitability during subsequent depolarization. Copyright © 2011 Elsevier Inc. All rights reserved.

CNS embryonal tumours: WHO 2016 and beyond.

PubMed

Pickles, J C; Hawkins, C; Pietsch, T; Jacques, T S

2018-02-01

Embryonal tumours of the central nervous system (CNS) present a significant clinical challenge. Many of these neoplasms affect young children, have a very high mortality and therapeutic strategies are often aggressive with poor long-term outcomes. There is a great need to accurately diagnose embryonal tumours, predict their outcome and adapt therapy to the individual patient's risk. For the first time in 2016, the WHO classification took into account molecular characteristics for the diagnosis of CNS tumours. This integration of histological features with genetic information has significantly changed the diagnostic work-up and reporting of tumours of the CNS. However, this remains challenging in embryonal tumours due to their previously unaccounted tumour heterogeneity. We describe the recent revisions made to the 4th edition of the WHO classification of CNS tumours and review the main changes, while highlighting some of the more common diagnostic testing strategies. © 2017 British Neuropathological Society.

Embryonic origin of the gnathostome vertebral skeleton

PubMed Central

Gillis, J. Andrew

2017-01-01

The vertebral column is a key component of the jawed vertebrate (gnathostome) body plan, but the primitive embryonic origin of this skeleton remains unclear. In tetrapods, all vertebral components (neural arches, haemal arches and centra) derive from paraxial mesoderm (somites). However, in teleost fishes, vertebrae have a dual embryonic origin, with arches derived from somites, but centra formed, in part, by secretion of bone matrix from the notochord. Here, we test the embryonic origin of the vertebral skeleton in a cartilaginous fish (the skate, Leucoraja erinacea) which serves as an outgroup to tetrapods and teleosts. We demonstrate, by cell lineage tracing, that both arches and centra are somite-derived. We find no evidence of cellular or matrix contribution from the notochord to the skate vertebral skeleton. These findings indicate that the earliest gnathostome vertebral skeleton was exclusively of somitic origin, with a notochord contribution arising secondarily in teleosts. PMID:29167367

Embryonic Heart Progenitors and Cardiogenesis

PubMed Central

Brade, Thomas; Pane, Luna S.; Moretti, Alessandra; Chien, Kenneth R.; Laugwitz, Karl-Ludwig

2013-01-01

The mammalian heart is a highly specialized organ, comprised of many different cell types arising from distinct embryonic progenitor populations during cardiogenesis. Three precursor populations have been identified to contribute to different myocytic and nonmyocytic cell lineages of the heart: cardiogenic mesoderm cells (CMC), the proepicardium (PE), and cardiac neural crest cells (CNCCs). This review will focus on molecular cues necessary for proper induction, expansion, and lineage-specific differentiation of these progenitor populations during cardiac development in vivo. Moreover, we will briefly discuss how the knowledge gained on embryonic heart progenitor biology can be used to develop novel therapeutic strategies for the management of congenital heart disease as well as for improvement of cardiac function in ischemic heart disease. PMID:24086063

Tension (re)builds: Biophysical mechanisms of embryonic wound repair.

PubMed

Zulueta-Coarasa, Teresa; Fernandez-Gonzalez, Rodrigo

2017-04-01

Embryonic tissues display an outstanding ability to rapidly repair wounds. Epithelia, in particular, serve as protective layers that line internal organs and form the skin. Thus, maintenance of epithelial integrity is of utmost importance for animal survival, particularly at embryonic stages, when an immune system has not yet fully developed. Rapid embryonic repair of epithelial tissues is conserved across species, and involves the collective migration of the cells around the wound. The migratory cell behaviours associated with wound repair require the generation and transmission of mechanical forces, not only for the cells to move, but also to coordinate their movements. Here, we review the forces involved in embryonic wound repair. We discuss how different force-generating structures are assembled at the molecular level, and the mechanisms that maintain the balance between force-generating structures as wounds close. Finally, we describe the mechanisms that cells use to coordinate the generation of mechanical forces around the wound. Collective cell movements and their misregulation have been associated with defective tissue repair, developmental abnormalities and cancer metastasis. Thus, we propose that understanding the role of mechanical forces during embryonic wound closure will be crucial to develop therapeutic interventions that promote or prevent collective cell movements under pathological conditions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Three-dimensional microCT imaging of murine embryonic development from immediate post-implantation to organogenesis: application for phenotyping analysis of early embryonic lethality in mutant animals.

PubMed

Ermakova, Olga; Orsini, Tiziana; Gambadoro, Alessia; Chiani, Francesco; Tocchini-Valentini, Glauco P

2018-04-01

In this work, we applied three-dimensional microCT imaging to study murine embryogenesis in the range from immediate post-implantation period (embryonic day 5.5) to mid-gestation (embryonic day 12.5) with the resolution up to 1.4 µm/voxel. Also, we introduce an imaging procedure for non-invasive volumetric estimation of an entire litter of embryos within the maternal uterine structures. This method allows for an accurate, detailed and systematic morphometric analysis of both embryonic and extra-embryonic components during embryogenesis. Three-dimensional imaging of unperturbed embryos was performed to visualize the egg cylinder, primitive streak, gastrulation and early organogenesis stages of murine development in the C57Bl6/N mouse reference strain. Further, we applied our microCT imaging protocol to determine the earliest point when embryonic development is arrested in a mouse line with knockout for tRNA splicing endonuclease subunit Tsen54 gene. Our analysis determined that the embryonic development in Tsen54 null embryos does not proceed beyond implantation. We demonstrated that application of microCT imaging to entire litter of non-perturbed embryos greatly facilitate studies to unravel gene function during early embryogenesis and to determine the precise point at which embryonic development is arrested in mutant animals. The described method is inexpensive, does not require lengthy embryos dissection and can be applicable for detailed analysis of mutant mice at laboratory scale as well as for high-throughput projects.

The Gastric Ganglion of Octopus vulgaris: Preliminary Characterization of Gene- and Putative Neurochemical-Complexity, and the Effect of Aggregata octopiana Digestive Tract Infection on Gene Expression

PubMed Central

Baldascino, Elena; Di Cristina, Giulia; Tedesco, Perla; Hobbs, Carl; Shaw, Tanya J.; Ponte, Giovanna; Andrews, Paul L. R.

2017-01-01

The gastric ganglion is the largest visceral ganglion in cephalopods. It is connected to the brain and is implicated in regulation of digestive tract functions. Here we have investigated the neurochemical complexity (through in silico gene expression analysis and immunohistochemistry) of the gastric ganglion in Octopus vulgaris and tested whether the expression of a selected number of genes was influenced by the magnitude of digestive tract parasitic infection by Aggregata octopiana. Novel evidence was obtained for putative peptide and non-peptide neurotransmitters in the gastric ganglion: cephalotocin, corticotrophin releasing factor, FMRFamide, gamma amino butyric acid, 5-hydroxytryptamine, molluscan insulin-related peptide 3, peptide PRQFV-amide, and tachykinin–related peptide. Receptors for cholecystokininA and cholecystokininB, and orexin2 were also identified in this context for the first time. We report evidence for acetylcholine, dopamine, noradrenaline, octopamine, small cardioactive peptide related peptide, and receptors for cephalotocin and octopressin, confirming previous publications. The effects of Aggregata observed here extend those previously described by showing effects on the gastric ganglion; in animals with a higher level of infection, genes implicated in inflammation (NFκB, fascin, serpinB10 and the toll-like 3 receptor) increased their relative expression, but TNF-α gene expression was lower as was expression of other genes implicated in oxidative stress (i.e., superoxide dismutase, peroxiredoxin 6, and glutathione peroxidase). Elevated Aggregata levels in the octopuses corresponded to an increase in the expression of the cholecystokininA receptor and the small cardioactive peptide-related peptide. In contrast, we observed decreased relative expression of cephalotocin, dopamine β-hydroxylase, peptide PRQFV-amide, and tachykinin-related peptide genes. A discussion is provided on (i) potential roles of the various molecules in food intake

Characterization of Na+ and Ca2+ Channels in Zebrafish Dorsal Root Ganglion Neurons

PubMed Central

Won, Yu-Jin; Ono, Fumihito; Ikeda, Stephen R.

2012-01-01

Background Dorsal root ganglia (DRG) somata from rodents have provided an excellent model system to study ion channel properties and modulation using electrophysiological investigation. As in other vertebrates, zebrafish (Danio rerio) DRG are organized segmentally and possess peripheral axons that bifurcate into each body segment. However, the electrical properties of zebrafish DRG sensory neurons, as compared with their mammalian counterparts, are relatively unexplored because a preparation suitable for electrophysiological studies has not been available. Methodology/Principal Findings We show enzymatically dissociated DRG neurons from juvenile zebrafish expressing Isl2b-promoter driven EGFP were easily identified with fluorescence microscopy and amenable to conventional whole-cell patch-clamp studies. Two kinetically distinct TTX-sensitive Na+ currents (rapidly- and slowly-inactivating) were discovered. Rapidly-inactivating INa were preferentially expressed in relatively large neurons, while slowly-inactivating INa was more prevalent in smaller DRG neurons. RT-PCR analysis suggests zscn1aa/ab, zscn8aa/ab, zscn4ab and zscn5Laa are possible candidates for these INa components. Voltage-gated Ca2+ currents (ICa) were primarily (87%) comprised of a high-voltage activated component arising from ω-conotoxin GVIA-sensitive CaV2.2 (N-type) Ca2+ channels. A few DRG neurons (8%) displayed a miniscule low-voltage-activated component. ICa in zebrafish DRG neurons were modulated by neurotransmitters via either voltage-dependent or -independent G-protein signaling pathway with large cell-to-cell response variability. Conclusions/Significance Our present results indicate that, as in higher vertebrates, zebrafish DRG neurons are heterogeneous being composed of functionally distinct subpopulations that may correlate with different sensory modalities. These findings provide the first comparison of zebrafish and rodent DRG neuron electrical properties and thus provide a basis for

Gravity and embryonic development

NASA Technical Reports Server (NTRS)

Young, R. S.

1976-01-01

The relationship between the developing embryo (both plant and animal) and a gravitational field has long been contemplated. The difficulty in designing critical experiments on the surface of the earth because of its background of 1 g, has been an obstacle to a resolution of the problem. Biological responses to gravity (particularly in plants) are obvious in many cases; however, the influence of gravity as an environmental input to the developing embryo is not as obvious and has proven to be extremely difficult to define. In spite of this, over the years numerous attempts have been made using a variety of embryonic materials to come to grips with the role of gravity in development. Three research tools are available: the centrifuge, the clinostat, and the orbiting spacecraft. Experimental results are now available from all three sources. Some tenuous conclusions are drawn, and an attempt at a unifying theory of gravitational influence on embryonic development is made.

KYNA analogue SZR72 modifies CFA-induced dural inflammation- regarding expression of pERK1/2 and IL-1β in the rat trigeminal ganglion.

PubMed

Lukács, M; Warfvinge, K; Kruse, L S; Tajti, J; Fülöp, F; Toldi, J; Vécsei, L; Edvinsson, L

2016-12-01

Neurogenic inflammation has for decades been considered an important part of migraine pathophysiology. In the present study, we asked the question if administration of a novel kynurenic acid analogue (SZR72), precursor of an excitotoxin antagonist and anti-inflammatory substance, can modify the neurogenic inflammatory response in the trigeminal ganglion. Inflammation in the trigeminal ganglion was induced by local dural application of Complete Freunds Adjuvant (CFA). Levels of phosphorylated MAP kinase pERK1/2 and IL-1β expression in V1 region of the trigeminal ganglion were investigated using immunohistochemistry and Western blot. Pretreatment with one dose of SZR72 abolished the CFA-induced pERK1/2 and IL-1β activation in the trigeminal ganglion. No significant change was noted in case of repeated treatment with SZR72 as compared to a single dose. This is the first study that demonstrates that one dose of KYNA analog before application of CFA can give anti-inflammatory response in a model of trigeminal activation, opening a new line for further investigations regarding possible effects of KYNA derivates.

Functional evaluation of a cell replacement therapy in the inner ear

PubMed Central

Hu, Zhengqing; Ulfendahl, Mats; Prieskorn, Diane M.; Olivius, N. Petri; Miller, Josef M.

2015-01-01

Hypothesis Cell replacement therapy in the inner ear will contribute to the functional recovery of hearing loss. Background Cell replacement therapy is a potentially powerful approach to replace degenerated or severely damaged spiral ganglion neurons. This study aimed at stimulating the neurite outgrowth of the implanted neurons and enhancing the potential therapeutic of inner ear cell implants. Methods Chronic electrical stimulation (CES) and exogenous neurotrophic growth factor (NGF) were applied to 46 guinea pigs transplanted with embryonic dorsal root ganglion (DRG) neurons four days post deafening. The animals were evaluated with the electrically-evoked auditory brain stem responses (EABRs) at experimental day 7, 11, 17, 24, 31. The animals were euthanized at day 31 and the inner ears were dissected out for immunohistochemistry investigation. Results Implanted DRG cells, identified by EGFP fluorescence and a neuronal marker, were found close to Rosenthal's canal in the adult inner ear for up to four weeks following transplantation. Extensive neurite projections clearly, greater than in non-treated animals, were observed to penetrate the bony modiolus and reach the spiral ganglion region in animals supplied with CES and/or NGF. There was, however, no significant difference in the thresholds of EABRs between DRG-transplanted-animals supplied with CES and/or NGF and DRG-transplanted animals without CES or NGF supplement. Conclusions The results suggest that CES and/or NGF can stimulate neurite outgrowth from implanted neurons, although based on EABR measurement these interventions did not induce functional connections to the central auditory pathway. Additional time or novel approaches may enhance functional responsiveness of implanted cells in the adult cochlea. PMID:19395986

Metabolic circadian rhythms in embryonic turtles.

PubMed

Loudon, Fiona Kay; Spencer, Ricky-John; Strassmeyer, Alana; Harland, Karen

2013-07-01

Oviparous species are model organisms for investigating embryonic development of endogenous physiological circadian rhythms without the influence of maternal biorhythms. Recent studies have demonstrated that heart rates and metabolic rates of embryonic turtles are not constant or always maximal and can be altered in response to the presence of embryos at a more advanced stage of development within the nest. A first step in understanding the physiological mechanisms underpinning these responses in embryonic ectothermic organisms is to develop metabolic profiles (e.g., heart rate) at different temperatures throughout incubation. Heart beat and rhythmic patterns or changes in development may represent important signals or cues within a nest and may be vital to coordinate synchronous hatching well in advance of the final stages of incubation. We developed baseline embryonic heart-rate profiles of embryos of the short-necked Murray River turtle (Emydura macquarii) to determine the stage of embryogenesis that metabolic circadian rhythms become established, if at all. Eggs were incubated at constant temperatures (26°C and 30°C) and heart rates were monitored at 6-h intervals over 24 h every 7-11 days until hatching. Circadian heart rate rhythms were detected at the mid-gestation period and were maintained until hatching. Heart rates throughout the day varied by up to 20% over 24 h and were not related to time of day. This study demonstrated that endogenous metabolic circadian rhythms in developing embryos in turtle eggs establish earlier in embryogenesis than those documented in other vertebrate taxa during embryogenesis. Early establishment of circadian rhythms in heart rates may be critical for communication among embryos and synchrony in hatching and emergence from the nest.

Embryonic kidney function in a chronic renal failure model in rodents.

PubMed

Fujimoto, Eisuke; Yamanaka, Shuichiro; Kurihara, Sho; Tajiri, Susumu; Izuhara, Luna; Katsuoka, Yuichi; Yokote, Shinya; Matsumoto, Kei; Kobayashi, Eiji; Okano, Hirotaka James; Chikaraishi, Tatsuya; Yokoo, Takashi

2017-08-01

Rapid advancements have been made in alternative treatments for renal diseases. Our goal for renal regeneration is to establish a kidney graft derived from human embryonic tissues. In this study, we investigated the effects of host renal failure on the structure and activity of transplanted embryonic kidney and bladder, and found that diuretics effectively induced urine production in the transplanted kidney. Uremic conditions were reproduced using a 5/6 renal infarction rat model. An embryonic kidney plus bladder (embryonic day 15) was isolated from a pregnant Lewis rat and transplanted into the para-aortic area of a 5/6 renal-infarcted Lewis rat. Following growth, the embryonic bladder was successfully anastomosed to the host ureter. We assessed graft function in terms of survival rates and found no differences between normal (n = 5) and renal failure (n = 8) groups (median survival: 70.5 vs 74.5 h; p = 0.331) in terms of survival, indicating that the grafts prolonged rat survival, even under renal failure conditions. Furosemide (n = 9) significantly increased urine volume compared with saline-treated controls (n = 7; p < 0.05), confirming that the grafts were functional. We also demonstrated the possibilities of an in vivo imaging system for determining the viability of transplanted embryonic kidney with bladder. The results of this study demonstrate that transplanted embryonic kidney and bladder can grow and function effectively, even under uremic conditions.

The ethics of patenting human embryonic stem cells.

PubMed

Chapman, Audrey R

2009-09-01

Just as human embryonic stem cell research has generated controversy about the uses of human embryos for research and therapeutic applications, human embryonic stem cell patents raise fundamental ethical issues. The United States Patent and Trademark Office has granted foundational patents, including a composition of matter (or product) patent to the Wisconsin Alumni Research Foundation (WARF), the University of Wisconsin-Madison's intellectual property office. In contrast, the European Patent Office rejected the same WARF patent application for ethical reasons. This article assesses the appropriateness of these patents placing the discussion in the context of the deontological and consequentialist ethical issues related to human embryonic stem cell patenting. It advocates for a patent system that explicitly takes ethical factors into account and explores options for new types of intellectual property arrangements consistent with ethical concerns.

Changes in the basal membrane of dorsal root ganglia Schwann cells explain the biphasic pattern of the peripheral neuropathy in streptozotocin-induced diabetic rats.

PubMed

Becker, Maria; Benromano, Tali; Shahar, Abraham; Nevo, Zvi; Pick, Chaim G

2014-12-01

Peripheral neuropathy is one of the main complications of diabetes mellitus. The current study demonstrated the bimodal pattern of diabetic peripheral neuropathy found in the behavioral study of pain perception in parallel to the histopathological findings in dorsal root ganglia (DRGs) neurons and satellite Schwann cell basement membranes. A gradual decrease in heparan sulfate content, with a reciprocal increase in deposited laminin in the basement membranes of dorsal root ganglia Schwann cells, was shown in streptozotocin-treated rats. In addition, the characteristic biphasic pain profiles were demonstrated in diabetic rats, as shown by hypersensitivity at the third week and hyposensitivity at the tenth week post-streptozotocin injection, accompanied by a continuous decrease in the sciatic nerve conduction velocity. It appears that these basal membrane abnormalities in content of heparan sulfate and laminin, noticed in diabetic rats, may underline the primary damage in dorsal ganglion sensory neurons, simultaneously with the bimodal painful profile in diabetic peripheral neuropathy, simulating the scenario of filtration rate in diabetic kidney.

Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro

PubMed Central

Leitmeyer, Katharina; Glutz, Andrea; Radojevic, Vesna; Setz, Cristian; Huerzeler, Nathan; Bumann, Helen; Bodmer, Daniel; Brand, Yves

2015-01-01

Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation. PMID:25918725

Inhibition of mTOR by Rapamycin Results in Auditory Hair Cell Damage and Decreased Spiral Ganglion Neuron Outgrowth and Neurite Formation In Vitro.

PubMed

Leitmeyer, Katharina; Glutz, Andrea; Radojevic, Vesna; Setz, Cristian; Huerzeler, Nathan; Bumann, Helen; Bodmer, Daniel; Brand, Yves

2015-01-01

Rapamycin is an antifungal agent with immunosuppressive properties. Rapamycin inhibits the mammalian target of rapamycin (mTOR) by blocking the mTOR complex 1 (mTORC1). mTOR is an atypical serine/threonine protein kinase, which controls cell growth, cell proliferation, and cell metabolism. However, less is known about the mTOR pathway in the inner ear. First, we evaluated whether or not the two mTOR complexes (mTORC1 and mTORC2, resp.) are present in the mammalian cochlea. Next, tissue explants of 5-day-old rats were treated with increasing concentrations of rapamycin to explore the effects of rapamycin on auditory hair cells and spiral ganglion neurons. Auditory hair cell survival, spiral ganglion neuron number, length of neurites, and neuronal survival were analyzed in vitro. Our data indicates that both mTOR complexes are expressed in the mammalian cochlea. We observed that inhibition of mTOR by rapamycin results in a dose dependent damage of auditory hair cells. Moreover, spiral ganglion neurite number and length of neurites were significantly decreased in all concentrations used compared to control in a dose dependent manner. Our data indicate that the mTOR may play a role in the survival of hair cells and modulates spiral ganglion neuronal outgrowth and neurite formation.

Magnetic resonance imaging for detecting root avulsions in traumatic adult brachial plexus injuries: protocol for a systematic review of diagnostic accuracy.

PubMed

Wade, Ryckie G; Takwoingi, Yemisi; Wormald, Justin C R; Ridgway, John P; Tanner, Steven; Rankine, James J; Bourke, Grainne

2018-05-19

Adult brachial plexus injuries (BPI) are becoming more common. The reconstruction and prognosis of pre-ganglionic injuries (root avulsions) are different to other types of BPI injury. Preoperative magnetic resonance imaging (MRI) is being used to identify root avulsions, but the evidence from studies of its diagnostic accuracy are conflicting. Therefore, a systematic review is needed to address uncertainty about the accuracy of MRI and to guide future research. We will conduct a systematic search of electronic databases alongside reference tracking. We will include studies of adults with traumatic BPI which report the accuracy of preoperative MRI (index test) against surgical exploration of the roots of the brachial plexus (reference standard) for detecting either of the two target conditions (any root avulsion or any pseudomeningocoele as a surrogate marker of root avulsion). We will exclude case reports, articles considering bilateral injuries and studies where the number of true positives, false positives, false negatives and true negatives cannot be derived. The methodological quality of the included studies will be assessed using a tailored version of the QUADAS-2 tool. Where possible, a bivariate model will be used for meta-analysis to obtain summary sensitivities and specificities for both target conditions. We will investigate heterogeneity in the performance of MRI according to field strength and the risk of bias if data permits. This review will summarise the current diagnostic accuracy of MRI for adult BPI, identify shortcomings and gaps in the literature and so help to guide future research. PROSPERO CRD42016049702 .

Tumor necrosis factor-alpha stimulation of calcitonin gene-related peptide expression and secretion from rat trigeminal ganglion neurons.

PubMed

Bowen, Elizabeth J; Schmidt, Thomas W; Firm, Christina S; Russo, Andrew F; Durham, Paul L

2006-01-01

Expression of the neuropeptide calcitonin gene-related peptide (CGRP) in trigeminal ganglion is implicated in neurovascular headaches and temporomandibular joint disorders. Elevation of cytokines contributes to the pathology of these diseases. However, a connection between cytokines and CGRP gene expression in trigeminal ganglion nerves has not been established. We have focused on the effects of the cytokine tumor necrosis factor-alpha (TNF-alpha). TNFR1 receptors were found on the majority of CGRP-containing rat trigeminal ganglion neurons. Treatment of cultures with TNF-alpha stimulated CGRP secretion. In addition, the intracellular signaling intermediate from the TNFR1 receptor, ceramide, caused a similar increase in CGRP release. TNF-alpha caused a coordinate increase in CGRP promoter activity. TNF-alpha treatment activated the transcription factor NF-kappaB, as well as the Jun N-terminal kinase (JNK) and p38 mitogen-activated protein (MAP) kinase pathways. The importance of TNF-alpha induction of MAP kinase pathways was demonstrated by inhibiting MAP kinases with pharmacological reagents and gene transfer with an adenoviral vector encoding MAP kinase phosphatase-1 (MKP-1). We propose that selective and regulated inhibition of MAP kinases in trigeminal neurons may be therapeutically beneficial for inflammatory disorders involving elevated CGRP levels.

Computerized tomography-guided sphenopalatine ganglion pulsed radiofrequency treatment in 16 patients with refractory cluster headaches: Twelve- to 30-month follow-up evaluations.

PubMed

Fang, Luo; Jingjing, Lu; Ying, Shen; Lan, Meng; Tao, Wang; Nan, Ji

2016-02-01

Sphenopalatine ganglion percutaneous radiofrequency thermocoagulation treatment can improve the symptoms of cluster headaches to some extent. However, as an ablation treatment, radiofrequency thermocoagulation treatment also has side effects. To preliminarily evaluate the efficacy and safety of a non-ablative computerized tomography-guided pulsed radiofrequency treatment of sphenopalatine ganglion in patients with refractory cluster headaches. We included and analysed 16 consecutive cluster headache patients who failed to respond to conservative therapy from the Pain Management Center at the Beijing Tiantan Hospital between April 2012 and September 2013 treated with pulsed radiofrequency treatment of sphenopalatine ganglion. Eleven of 13 episodic cluster headaches patients and one of three chronic cluster headaches patient were completely relieved of the headache within an average of 6.3 ± 6.0 days following the treatment. Two episodic cluster headache patients and two chronic cluster headache patients showed no pain relief following the treatment. The mean follow-up time was 17.0 ± 5.5 months. All patients enrolled in this study showed no treatment-related side effects or complications. Our data show that patients with refractory episodic cluster headaches were quickly, effectively and safely relieved from the cluster period after computerized tomography-guided pulsed radiofrequency treatment of sphenopalatine ganglion, suggesting that it may be a therapeutic option if conservative treatments fail. © International Headache Society 2015.

Effects of different feeder layers on culture of bovine embryonic stem cell-like cells in vitro.

PubMed

Cong, Shan; Cao, Guifang; Liu, Dongjun

2014-12-01

To find a suitable feeder layer is important for successful culture conditions of bovine embryonic stem cell-like cells. In this study, expression of pluripotency-related genes OCT4, SOX2 and NANOG in bovine embryonic stem cell-like cells on mouse embryonic fibroblast feeder layers at 1-5 passages were monitored in order to identify the possible reason that bovine embryonic stem cell-like cells could not continue growth and passage. Here, we developed two novel feeder layers, mixed embryonic fibroblast feeder layers of mouse and bovine embryonic fibroblast at different ratios and sources including mouse fibroblast cell lines. The bovine embryonic stem cell-like cells generated in our study displayed typical stem cell morphology and expressed specific markers such as OCT4, stage-specific embryonic antigen 1 and 4, alkaline phosphatase, SOX2, and NANOG mRNA levels. When feeder layers and cell growth factors were removed, the bovine embryonic stem cell-like cells formed embryoid bodies in a suspension culture. Furthermore, we compared the expression of the pluripotent markers during bovine embryonic stem cell-like cell in culture on mixed embryonic fibroblast feeder layers, including mouse fibroblast cell lines feeder layers and mouse embryonic fibroblast feeder layers by real-time quantitative polymerase chain reaction. Results suggested that mixed embryonic fibroblast and sources including mouse fibroblast cell lines feeder layers were more suitable for long-term culture and growth of bovine embryonic stem cell-like cells than mouse embryonic fibroblast feeder layers. The findings may provide useful experimental data for the establishment of an appropriate culture system for bovine embryonic stem cell lines.

Role of adiponectin in delayed embryonic development of the short-nosed fruit bat, Cynopterus sphinx.

PubMed

Anuradha; Krishna, Amitabh

2014-12-01

The aim of this study was to evaluate the role of adiponectin in the delayed embryonic development of Cynopterus sphinx. Adiponectin receptor (ADIPOR1) abundance was first observed to be lower during the delayed versus non-delayed periods of utero-embryonic unit development. The effects of adiponectin treatment on embryonic development were then evaluated during the period of delayed development. Exogenous treatment increased the in vivo rate of embryonic development, as indicated by an increase in weight, ADIPOR1 levels in the utero-embryonic unit, and histological changes in embryonic development. Treatment with adiponectin during embryonic diapause showed a significant increase in circulating progesterone and estradiol concentrations, and in production of their receptors in the utero-embryonic unit. The adiponectin-induced increase in estradiol synthesis was correlated with increased cell survival (BCL2 protein levels) and cell proliferation (PCNA protein levels) in the utero-embryonic unit, suggesting an indirect effect of adiponectin via estradiol synthesis by the ovary. An in vitro study further confirmed the in vivo findings that adiponectin treatment increases PCNA levels together with increased uptake of glucose by increasing the abundance of glucose transporter 8 (GLUT8) in the utero-embryonic unit. The in vitro study also revealed that adiponectin, together with estradiol but not alone, significantly increased ADIPOR1 protein levels. Thus, adiponectin works in concert with estradiol to increase glucose transport to the utero-embryonic unit and promote cell proliferation, which together accelerate embryonic development. © 2014 Wiley Periodicals, Inc.

PTBP1 Is Required for Embryonic Development before Gastrulation

PubMed Central

Suckale, Jakob; Wendling, Olivia; Masjkur, Jimmy; Jäger, Melanie; Münster, Carla; Anastassiadis, Konstantinos; Stewart, A. Francis; Solimena, Michele

2011-01-01

Polypyrimidine-tract binding protein 1 (PTBP1) is an important cellular regulator of messenger RNAs influencing the alternative splicing profile of a cell as well as its mRNA stability, location and translation. In addition, it is diverted by some viruses to facilitate their replication. Here, we used a novel PTBP1 knockout mouse to analyse the tissue expression pattern of PTBP1 as well as the effect of its complete removal during development. We found evidence of strong PTBP1 expression in embryonic stem cells and throughout embryonic development, especially in the developing brain and spinal cord, the olfactory and auditory systems, the heart, the liver, the kidney, the brown fat and cartilage primordia. This widespread distribution points towards a role of PTBP1 during embryonic development. Homozygous offspring, identified by PCR and immunofluorescence, were able to implant but were arrested or retarded in growth. At day 7.5 of embryonic development (E7.5) the null mutants were about 5x smaller than the control littermates and the gap in body size widened with time. At mid-gestation, all homozygous embryos were resorbed/degraded. No homozygous mice were genotyped at E12 and the age of weaning. Embryos lacking PTBP1 did not display differentiation into the 3 germ layers and cavitation of the epiblast, which are hallmarks of gastrulation. In addition, homozygous mutants displayed malformed ectoplacental cones and yolk sacs, both early supportive structure of the embryo proper. We conclude that PTBP1 is not required for the earliest isovolumetric divisions and differentiation steps of the zygote up to the formation of the blastocyst. However, further post-implantation development requires PTBP1 and stalls in homozygous null animals with a phenotype of dramatically reduced size and aberration in embryonic and extra-embryonic structures. PMID:21423341

PTBP1 is required for embryonic development before gastrulation.

PubMed

Suckale, Jakob; Wendling, Olivia; Masjkur, Jimmy; Jäger, Melanie; Münster, Carla; Anastassiadis, Konstantinos; Stewart, A Francis; Solimena, Michele

2011-02-17

Polypyrimidine-tract binding protein 1 (PTBP1) is an important cellular regulator of messenger RNAs influencing the alternative splicing profile of a cell as well as its mRNA stability, location and translation. In addition, it is diverted by some viruses to facilitate their replication. Here, we used a novel PTBP1 knockout mouse to analyse the tissue expression pattern of PTBP1 as well as the effect of its complete removal during development. We found evidence of strong PTBP1 expression in embryonic stem cells and throughout embryonic development, especially in the developing brain and spinal cord, the olfactory and auditory systems, the heart, the liver, the kidney, the brown fat and cartilage primordia. This widespread distribution points towards a role of PTBP1 during embryonic development. Homozygous offspring, identified by PCR and immunofluorescence, were able to implant but were arrested or retarded in growth. At day 7.5 of embryonic development (E7.5) the null mutants were about 5x smaller than the control littermates and the gap in body size widened with time. At mid-gestation, all homozygous embryos were resorbed/degraded. No homozygous mice were genotyped at E12 and the age of weaning. Embryos lacking PTBP1 did not display differentiation into the 3 germ layers and cavitation of the epiblast, which are hallmarks of gastrulation. In addition, homozygous mutants displayed malformed ectoplacental cones and yolk sacs, both early supportive structure of the embryo proper. We conclude that PTBP1 is not required for the earliest isovolumetric divisions and differentiation steps of the zygote up to the formation of the blastocyst. However, further post-implantation development requires PTBP1 and stalls in homozygous null animals with a phenotype of dramatically reduced size and aberration in embryonic and extra-embryonic structures.

Embryonic Stem Cells: Isolation, Characterization and Culture

NASA Astrophysics Data System (ADS)

Amit, Michal; Itskovitz-Eldor, Joseph

Embryonic stem cells are pluripotent cells isolated from the mammalian blastocyst. Traditionally, these cells have been derived and cultured with mouse embryonic fibroblast (MEF) supportive layers, which allow their continuous growth in an undifferentiated state. However, for any future industrial or clinical application hESCs should be cultured in reproducible, defined, and xeno-free culture system, where exposure to animal pathogens is prevented. From their derivation in 1998 the methods for culturing hESCs were significantly improved. This chapter wills discuss hESC characterization and the basic methods for their derivation and maintenance.

Macrophage migration inhibitory factor acts as a neurotrophin in the developing inner ear.

PubMed

Bank, Lisa M; Bianchi, Lynne M; Ebisu, Fumi; Lerman-Sinkoff, Dov; Smiley, Elizabeth C; Shen, Yu-chi; Ramamurthy, Poornapriya; Thompson, Deborah L; Roth, Therese M; Beck, Christine R; Flynn, Matthew; Teller, Ryan S; Feng, Luming; Llewellyn, G Nicholas; Holmes, Brandon; Sharples, Cyrrene; Coutinho-Budd, Jaeda; Linn, Stephanie A; Chervenak, Andrew P; Dolan, David F; Benson, Jennifer; Kanicki, Ariane; Martin, Catherine A; Altschuler, Richard; Koch, Alisa E; Koch, Alicia E; Jewett, Ethan M; Germiller, John A; Barald, Kate F

2012-12-01

This study is the first to demonstrate that macrophage migration inhibitory factor (MIF), an immune system 'inflammatory' cytokine that is released by the developing otocyst, plays a role in regulating early innervation of the mouse and chick inner ear. We demonstrate that MIF is a major bioactive component of the previously uncharacterized otocyst-derived factor, which directs initial neurite outgrowth from the statoacoustic ganglion (SAG) to the developing inner ear. Recombinant MIF acts as a neurotrophin in promoting both SAG directional neurite outgrowth and neuronal survival and is expressed in both the developing and mature inner ear of chick and mouse. A MIF receptor, CD74, is found on both embryonic SAG neurons and adult mouse spiral ganglion neurons. Mif knockout mice are hearing impaired and demonstrate altered innervation to the organ of Corti, as well as fewer sensory hair cells. Furthermore, mouse embryonic stem cells become neuron-like when exposed to picomolar levels of MIF, suggesting the general importance of this cytokine in neural development.

Embryonic mammary signature subsets are activated in Brca1-/- and basal-like breast cancers

PubMed Central

2013-01-01

Introduction Cancer is often suggested to result from development gone awry. Links between normal embryonic development and cancer biology have been postulated, but no defined genetic basis has been established. We recently published the first transcriptomic analysis of embryonic mammary cell populations. Embryonic mammary epithelial cells are an immature progenitor cell population, lacking differentiation markers, which is reflected in their very distinct genetic profiles when compared with those of their postnatal descendents. Methods We defined an embryonic mammary epithelial signature that incorporates the most highly expressed genes from embryonic mammary epithelium when compared with the postnatal mammary epithelial cells. We looked for activation of the embryonic mammary epithelial signature in mouse mammary tumors that formed in mice in which Brca1 had been conditionally deleted from the mammary epithelium and in human breast cancers to determine whether any genetic links exist between embryonic mammary cells and breast cancers. Results Small subsets of the embryonic mammary epithelial signature were consistently activated in mouse Brca1-/- tumors and human basal-like breast cancers, which encoded predominantly transcriptional regulators, cell-cycle, and actin cytoskeleton components. Other embryonic gene subsets were found activated in non-basal-like tumor subtypes and repressed in basal-like tumors, including regulators of neuronal differentiation, transcription, and cell biosynthesis. Several embryonic genes showed significant upregulation in estrogen receptor (ER)-negative, progesterone receptor (PR)-negative, and/or grade 3 breast cancers. Among them, the transcription factor, SOX11, a progenitor cell and lineage regulator of nonmammary cell types, is found highly expressed in some Brca1-/- mammary tumors. By using RNA interference to silence SOX11 expression in breast cancer cells, we found evidence that SOX11 regulates breast cancer cell

Reliable, responsive pacemaking and pattern generation with minimal cell numbers: the crustacean cardiac ganglion.

PubMed

Cooke, Ian M

2002-04-01

Investigations of the electrophysiology of crustacean cardiac ganglia over the last half-century are reviewed for their contributions to elucidating the cellular mechanisms and interactions by which a small (as few as nine cells) neuronal network accomplishes extremely reliable, rhythmical, patterned activation of muscular activity-in this case, beating of the neurogenic heart. This ganglion is thus a model for pacemaking and central pattern generation. Favorable anatomy has permitted voltage- and space-clamp analyses of voltage-dependent ionic currents that endow each neuron with the intrinsic ability to respond with rhythmical, patterned impulse activity to nonpatterned stimulation. The crustacean soma and initial axon segment do not support impulse generation but integrate input from stretch-sensitive dendrites and electrotonic and chemically mediated synapses on axonal processes in neuropils. The soma and initial axon produce a depolarization-activated, calcium-mediated, sustained potential, the "driver potential," so-called because it drives a train of impulses at the "trigger zone" of the axon. Extreme reliability results from redundancy and the electrotonic coupling and synaptic interaction among all the neurons. Complex modulation by central nervous system inputs and by neurohormones to adjust heart pumping to physiological demands has long been demonstrated, but much remains to be learned about the cellular and molecular mechanisms of action. The continuing relevance of the crustacean cardiac ganglion as a relatively simple model for pacemaking and central pattern generation is confirmed by the rapidly widening documentation of intrinsic potentials such as plateau potentials in neurons of all major animal groups. The suite of ionic currents (a slowly inactivating calcium current and various potassium currents, with variations) observed for the crustacean cardiac ganglion have been implicated in or proven to underlie a majority of the intrinsic potentials

Root architecture simulation improves the inference from seedling root phenotyping towards mature root systems.

PubMed

Zhao, Jiangsan; Bodner, Gernot; Rewald, Boris; Leitner, Daniel; Nagel, Kerstin A; Nakhforoosh, Alireza

2017-02-01

Root phenotyping provides trait information for plant breeding. A shortcoming of high-throughput root phenotyping is the limitation to seedling plants and failure to make inferences on mature root systems. We suggest root system architecture (RSA) models to predict mature root traits and overcome the inference problem. Sixteen pea genotypes were phenotyped in (i) seedling (Petri dishes) and (ii) mature (sand-filled columns) root phenotyping platforms. The RSA model RootBox was parameterized with seedling traits to simulate the fully developed root systems. Measured and modelled root length, first-order lateral number, and root distribution were compared to determine key traits for model-based prediction. No direct relationship in root traits (tap, lateral length, interbranch distance) was evident between phenotyping systems. RootBox significantly improved the inference over phenotyping platforms. Seedling plant tap and lateral root elongation rates and interbranch distance were sufficient model parameters to predict genotype ranking in total root length with an RSpearman of 0.83. Parameterization including uneven lateral spacing via a scaling function substantially improved the prediction of architectures underlying the differently sized root systems. We conclude that RSA models can solve the inference problem of seedling root phenotyping. RSA models should be included in the phenotyping pipeline to provide reliable information on mature root systems to breeding research. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Root architecture simulation improves the inference from seedling root phenotyping towards mature root systems

PubMed Central

Zhao, Jiangsan; Rewald, Boris; Leitner, Daniel; Nagel, Kerstin A.; Nakhforoosh, Alireza

2017-01-01

Abstract Root phenotyping provides trait information for plant breeding. A shortcoming of high-throughput root phenotyping is the limitation to seedling plants and failure to make inferences on mature root systems. We suggest root system architecture (RSA) models to predict mature root traits and overcome the inference problem. Sixteen pea genotypes were phenotyped in (i) seedling (Petri dishes) and (ii) mature (sand-filled columns) root phenotyping platforms. The RSA model RootBox was parameterized with seedling traits to simulate the fully developed root systems. Measured and modelled root length, first-order lateral number, and root distribution were compared to determine key traits for model-based prediction. No direct relationship in root traits (tap, lateral length, interbranch distance) was evident between phenotyping systems. RootBox significantly improved the inference over phenotyping platforms. Seedling plant tap and lateral root elongation rates and interbranch distance were sufficient model parameters to predict genotype ranking in total root length with an RSpearman of 0.83. Parameterization including uneven lateral spacing via a scaling function substantially improved the prediction of architectures underlying the differently sized root systems. We conclude that RSA models can solve the inference problem of seedling root phenotyping. RSA models should be included in the phenotyping pipeline to provide reliable information on mature root systems to breeding research. PMID:28168270

Characterising the developmental profile of human embryonic stem cell-derived medium spiny neuron progenitors and assessing mature neuron function using a CRISPR-generated human DARPP-32WT/eGFP-AMP reporter line.

PubMed

Hunt, C P J; Pouton, C W; Haynes, J M

2017-06-01

In the developing ventral telencephalon, cells of the lateral ganglionic eminence (LGE) give rise to all medium spiny neurons (MSNs). This development occurs in response to a highly orchestrated series of morphogenetic stimuli that pattern the resultant neurons as they develop. Striatal MSNs are characterised by expression of dopamine receptors, dopamine-and cyclic AMP-regulated phosphoprotein (DARPP32) and the neurotransmitter GABA. In this study, we demonstrate that fine tuning Wnt and hedgehog (SHH) signaling early in human embryonic stem cell differentiation can induce a subpallial progenitor molecular profile. Stimulation of TGFβ signaling pathway by activin-A further supports patterning of progenitors to striatal precursors which adopt an LGE-specific gene signature. Moreover, we report that these MSNs also express markers associated with mature neuron function (cannabinoid, adenosine and dopamine receptors). To facilitate live-cell identification we generated a human embryonic stem cell line using CRISPR-mediated gene editing at the DARPP32 locus (DARPP32 WT/eGFP-AMP-LacZ ). The addition of dopamine to MSNs either increased, decreased or had no effect on intracellular calcium, indicating the presence of multiple dopamine receptor subtypes. In summary, we demonstrate greater control over early fate decisions using activin-A, Wnt and SHH to direct differentiation into MSNs. We also generate a DARPP32 reporter line that enables deeper pharmacological profiling and interrogation of complex receptor interactions in human MSNs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Prevention of Excitotoxicity in Primary Retinal Ganglion Cells by (+)-Pentazocine, a Sigma Receptor-1-Specific Ligand

PubMed Central

Dun, Ying; Thangaraju, Muthusamy; Prasad, Puttur; Ganapathy, Vadivel; Smith, Sylvia B.

2013-01-01

Purpose σRs are non-opioid, non-phencyclidine binding sites with robust neuroprotective properties. Previously, we induced death in the RGC-5 cell line using very high concentrations (1 mM) of the excitatory amino acids glutamate (Glu) and homocysteine (Hcy) and demonstrated that the σR1 ligand (+)-pentazocine ((+)-PTZ) could protect against cell death. The purpose of the present study was to establish a physiologically relevant paradigm for testing the neuroprotective effect of (+)-PTZ in retinal ganglion cells. Methods Primary ganglion cells (1°GCs) were isolated by immunopanning from retinas of 1-day-old mice, maintained in culture for 3 days and then exposed to 10, 20, 25 or 50 µM Glu or 10, 25, 50 or 100 µM Hcy for 6 or 18 h in the presence or absence of (+)-PTZ (0.5, 1, 3 µM). Cell viability was measured using the Live/Dead and ApopTag Fluorescein In Situ Assays. Expression of σR1 was assessed by immunocytochemistry, RT-PCR and western blotting. Morphological appearance of live ganglion cells and their processes was examined over time (0, 3, 6, 18 h) by differential interference contrast (DIC) microscopy following exposure to excitotoxins in the presence or absence of (+)-PTZ. Results 1°GCs showed robust σR1 expression. The cells are exquisitely sensitive to Glu or Hcy toxicity (6 h treatment with 25 or 50 µM Glu or 50 or 100 µM Hcy induced marked cell death). 1°GCs pre-treated 1 h with (+)-PTZ followed by 18 h co-treatment with 25 µM Glu and (+)-PTZ showed a marked decrease in cell death: (25 µM Glu alone: 50%; 25 µM Glu/0.5 µM (+)-PTZ: 38%; 25 µM Glu/1 µM (+)-PTZ: 20%; 25 µM Glu/3 µM (+)-PTZ: 18%). Similar results were obtained with Hcy. σR1 mRNA and protein levels did not change in the presence of the excitotoxins. DIC examination of cells exposed to excitotoxins revealed substantial disruption of neuronal processes; co-treatment with (+)-PTZ revealed marked preservation of these processes. The stereoselective effect of (+)-PTZ for �

A toolbox to explore the mechanics of living embryonic tissues

PubMed Central

Campàs, Otger

2016-01-01

The sculpting of embryonic tissues and organs into their functional morphologies involves the spatial and temporal regulation of mechanics at cell and tissue scales. Decades of in vitro work, complemented by some in vivo studies, have shown the relevance of mechanical cues in the control of cell behaviors that are central to developmental processes, but the lack of methodologies enabling precise, quantitative measurements of mechanical cues in vivo have hindered our understanding of the role of mechanics in embryonic development. Several methodologies are starting to enable quantitative studies of mechanics in vivo and in situ, opening new avenues to explore how mechanics contributes to shaping embryonic tissues and how it affects cell behavior within developing embryos. Here we review the present methodologies to study the role of mechanics in living embryonic tissues, considering their strengths and drawbacks as well as the conditions in which they are most suitable. PMID:27061360

Melatonin regulates delayed embryonic development in the short-nosed fruit bat, Cynopterus sphinx.

PubMed

Banerjee, Arnab; Meenakumari, K J; Udin, S; Krishna, A

2009-12-01

The aim of the present study was to evaluate the seasonal variation in serum melatonin levels and their relationship to the changes in the serum progesterone level, ovarian steroidogenesis, and embryonic development during two successive pregnancies of Cynopterus sphinx. Circulating melatonin concentrations showed two peaks; one coincided with the period of low progesterone synthesis and delayed embryonic development, whereas the second peak coincided with regressing corpus luteum. This finding suggests that increased serum melatonin level during November-December may be responsible for delayed embryonic development by suppressing progesterone synthesis. The study showed increased melatonin receptors (MTNR1A and MTNR1B) in the corpus luteum and in the utero-embryonic unit during the period of delayed embryonic development. The in vitro study showed that a high dose of melatonin suppressed progesterone synthesis, whereas a lower dose of melatonin increased progesterone synthesis by the ovary. The effects of melatonin on ovarian steroidogenesis are mediated through changes in the expression of peripheral-type benzodiazepine receptor, P450 side chain cleavage enzyme, and LH receptor proteins. This study further showed a suppressive impact of melatonin on the progesterone receptor (PGR) in the utero-embryonic unit; this effect might contribute to delayed embryonic development in C. sphinx. The results of the present study thus suggest that a high circulating melatonin level has a dual contribution in retarding embryonic development in C. sphinx by impairing progesterone synthesis as well as by inhibiting progesterone action by reducing expression of PGR in the utero-embryonic unit.

Coding of position by simultaneously recorded sensory neurones in the cat dorsal root ganglion

PubMed Central

Stein, R B; Weber, D J; Aoyagi, Y; Prochazka, A; Wagenaar, J B M; Shoham, S; Normann, R A

2004-01-01

Muscle, cutaneous and joint afferents continuously signal information about the position and movement of individual joints. How does the nervous system extract more global information, for example about the position of the foot in space? To study this question we used microelectrode arrays to record impulses simultaneously from up to 100 discriminable nerve cells in the L6 and L7 dorsal root ganglia (DRG) of the anaesthetized cat. When the hindlimb was displaced passively with a random trajectory, the firing rate of the neurones could be predicted from a linear sum of positions and velocities in Cartesian (x, y), polar or joint angular coordinates. The process could also be reversed to predict the kinematics of the limb from the firing rates of the neurones with an accuracy of 1–2 cm. Predictions of position and velocity could be combined to give an improved fit to limb position. Decoders trained using random movements successfully predicted cyclic movements and movements in which the limb was displaced from a central point to various positions in the periphery. A small number of highly informative neurones (6–8) could account for over 80% of the variance in position and a similar result was obtained in a realistic limb model. In conclusion, this work illustrates how populations of sensory receptors may encode a sense of limb position and how the firing of even a small number of neurones can be used to decode the position of the limb in space. PMID:15331686