Electrical stimulation of dorsal root entry zone attenuates wide-dynamic range neuronal activity in rats

PubMed Central

Yang, Fei; Zhang, Chen; Xu, Qian; Tiwari, Vinod; He, Shao-Qiu; Wang, Yun; Dong, Xinzhong; Vera-Portocarrero, Louis P.; Wacnik, Paul W.; Raja, Srinivasa N.; Guan, Yun

2014-01-01

Objectives Recent clinical studies suggest that neurostimulation at the dorsal root entry zone (DREZ) may alleviate neuropathic pain. However, the mechanisms of action for this therapeutic effect are unclear. Here, we examined whether DREZ stimulation inhibits spinal wide-dynamic-range (WDR) neuronal activity in nerve-injured rats. Materials and Methods We conducted in vivo extracellular single-unit recordings of WDR neurons in rats after an L5 spinal nerve ligation (SNL) or sham surgery. We set bipolar electrical stimulation (50 Hz, 0.2 ms, 5 min) of the DREZ at the intensity that activated only Aα/β-fibers by measuring the lowest current at which DREZ stimulation evoked a peak antidromic sciatic Aα/β-compound action potential without inducing an Aδ/C-compound action potential (i.e., Ab1). Results The elevated spontaneous activity rate of WDR neurons in SNL rats [n=25; data combined from day 14–16 (n = 15) and day 45–75 post-SNL groups (n=10)] was significantly decreased from the pre-stimulation level (p<0.01) at 0–15 min and 30–45 min post-stimulation. In both sham-operated (n=8) and nerve-injured rats, DREZ stimulation attenuated the C-component, but not A-component, of the WDR neuronal response to graded intracutaneous electrical stimuli (0.1–10 mA, 2 ms) applied to the skin receptive field. Further, DREZ stimulation blocked windup (a short form of neuronal sensitization) to repetitive noxious stimuli (0.5 Hz) at 0–15 min in all groups (p<0.05). Conclusions Attenuation of WDR neuronal activity may contribute to DREZ stimulation-induced analgesia. This finding supports the notion that DREZ may be a useful target for neuromodulatory control of pain. PMID:25308522

Central projections and entries of capsaicin-sensitive muscle afferents.

PubMed

Della Torre, G; Lucchi, M L; Brunetti, O; Pettorossi, V E; Clavenzani, P; Bortolami, R

1996-03-25

The entry pathway and central distribution of A delta and C muscle afferents within the central nervous system (CNS) were investigated by combining electron microscopy and electrophysiological analysis after intramuscular injection of capsaicin. The drug was injected into the rat lateral gastrocnemius (LG) and extraocular (EO) muscles. The compound action potentials of LG nerve and the evoked field potentials recorded in semilunar ganglion showed an immediate and permanent reduction in A delta and C components. The morphological data revealed degenerating unmyelinated axons and terminals in the inner sublamina II and in the border of laminae I-II of the dorsal horn at L4-L5 and C1-C2 (subnucleus caudalis trigemini) spinal cord segments. Most degenerating terminals were the central bouton (C) of type I and II synaptic glomeruli. Furthermore, degenerating peripheral axonal endings (V2) presynaptic to normal C were found. Since V2 were previously found degenerated after cutting the oculomotor nerve (ON) or L4 ventral root, we conclude that some A delta and C afferents from LG and EO muscles entering the CNS by ON or ventral roots make axoaxonic synapses on other primary afferents to promote an afferent control of sensory input.

[Partial dorsal root rhizotomy increases the anterograde transportation of neunotrophic factors in primary sensory neuron].

PubMed

Long, Shuang-lian; Li, Yong-mei; Yuan, Yuan; Wang, Ting-hua; Wu, Lin-yan

2005-05-01

To investigate whether partial dorsal root rhizotomy promotes the anterograde Five adult cats were transportation of BDNF, NT-3 and GDNF in the primary sensory neuron. Subjected to unilateral spared root rhizotomy (the DRGs of L1-L5 and L7-S2 were removed, but L6 DRG was spared) and bilateral dorsal roots of L6 were ligated at the same time. Three days after operation, dorsal roots were taken out and made into frozen sections 20 microm in thickness. The sections were stained using specific BDNF, NT-3, GDNF antibody (1:1500) by ABC method. The immunoreactive density was observed in a site near DRG and a site near spinal cord. In the control group (with spared L6 DRG), there were no marked differences in NT-3 and GDNF immunoreactivity between the site near DRG and the site near spinal cord, while BDNF immunoreactivity was more intense in the site near DRG than that in the site near spinal cord. In the operation group, the immunoreactivity of each neurotrophin in the site near DRG was stronger than that in the site near spinal cord, and the immunoreactivities of BDNF, NT-3, GDNF in the site near DRG of the operation were stronger than those of the control group respectively. The increasing of immunoreactivities of neurotrophins near DRG following partial dorsal root rhizotomy suggests that partial dorsal root rhizotomy can promote their anterograde transportation from spared DRG to the spinal cord.

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.

Dorsal root ganglia volume differentiates schwannomatosis and neurofibromatosis 2.

PubMed

Godel, Tim; Mautner, Victor-Felix; Farschtschi, Said; Pham, Mirko; Schwarz, Daniel; Kronlage, Moritz; Gugel, Isabel; Heiland, Sabine; Bendszus, Martin; Bäumer, Philipp

2018-04-01

Schwannomatosis and neurofibromatosis type 2 are hereditary tumor syndromes, and peripheral neuropathy has been reported in both. We prospectively applied in vivo morphometric measurement of dorsal root ganglia volume in 16 schwannomatosis patients, 14 neurofibromatosis type 2 patients, and 26 healthy controls by magnetic resonance neurography. Compared to healthy controls, dorsal root ganglia hypertrophy was a consistent finding in neurofibromatosis type 2 (L3, + 267%; L4, + 235%; L5, + 241%; S1, + 300%; S2, + 242%; Bonferroni-adjusted p < 0.001) but not in schwannomatosis. Dorsal root ganglia may be a vulnerable site in origination of areflexia and sensory loss and a useful diagnostic marker in neurofibromatosis type 2. Ann Neurol 2018;83:854-857. © 2018 American Neurological Association.

Participation of satellite glial cells of the dorsal root ganglia in acute nociception.

PubMed

Lemes, Júlia Borges Paes; de Campos Lima, Tais; Santos, Débora Oliveira; Neves, Amanda Ferreira; de Oliveira, Fernando Silva; Parada, Carlos Almicar; da Cruz Lotufo, Celina Monteiro

2018-05-29

At dorsal root ganglia, neurons and satellite glial cells (SGC) can communicate through ATP release and P2X7 receptor activation. SGCs are also interconnected by gap junctions and have been previously implicated in modulating inflammatory and chronic pain.We now present evidence that SGCs are also involved in processing acute nociception in rat dorsal root ganglia. Using primary dorsal root ganglia cultures we observed that calcium transients induced in neurons by capsaicin administration were followed by satellite glial cells activation. Only satellite glial cells response was reduced by administration of the P2X7 receptor antagonist A740003. In vivo, acute nociception induced by intraplantar injection of capsaicin in rats was inhibited by A740003 or by the gap junction blocker carbenoxolone administered at the dorsal root ganglia (L5 level). Both drugs also reduced the second phase of the formalin test. These results suggest that communication between neurons and satellite glial cells is not only involved in inflammatory or pathological pain, but also in the transmission of the nociceptive signal, possibly in situations involving C-fiber activation. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

Analysis of Expression Pattern and Genetic Deletion of Netrin5 in the Developing Mouse

PubMed Central

Garrett, Andrew M.; Jucius, Thomas J.; Sigaud, Liam P. R.; Tang, Fu-Lei; Xiong, Wen-Cheng; Ackerman, Susan L.; Burgess, Robert W.

2016-01-01

Boundary cap cells (BCC) are a transient, neural-crest-derived population found at the motor exit point (MEP) and dorsal root entry zone (DREZ) of the embryonic spinal cord. These cells contribute to the central/peripheral nervous system (CNS/PNS) boundary, and in their absence neurons and glia from the CNS migrate into the PNS. We found Netrin5 (Ntn5), a previously unstudied member of the netrin gene family, to be robustly expressed in BCC. We generated Ntn5 knockout mice and examined neurodevelopmental and BCC-related phenotypes. No abnormalities in cranial nerve guidance, dorsal root organization, or sensory projections were found. However, Ntn5 mutant embryos did have ectopic motor neurons (MNs) that migrated out of the ventral horn and into the motor roots. Previous studies have implicated semaphorin6A (Sema6A) in BCC signaling to plexinA2 (PlxnA2)/neuropilin2 (Nrp2) in MNs in restricting MN cell bodies to the ventral horn, particularly in the caudal spinal cord. In Ntn5 mutants, ectopic MNs are likely to be a different population, as more ectopias were found rostrally. Furthermore, ectopic MNs in Ntn5 mutants were not immunoreactive for NRP2. The netrin receptor deleted in colorectal cancer (DCC) is a potential receptor for NTN5 in MNs, as similar ectopic neurons were found in Dcc mutant mice, but not in mice deficient for other netrin receptors. Thus, Ntn5 is a novel netrin family member that is expressed in BCC, functioning to prevent MN migration out of the CNS. PMID:26858598

The action of chlorphenesin carbamate on the frog spinal cord.

PubMed

Aihara, H; Kurachi, M; Nakane, S; Sasajima, M; Ohzeki, M

1980-02-01

Studies were carried out to elucidate the mechanism of action of chlorphenesin carbamate (CPC) and to compare the effect of the drug with that of mephenesin on the isolated bullfrog spinal cord. Ventral and dorsal root potentials were recorded by means of the sucrose-gap method. CPC caused marked hyperpolarizations and depressed spontaneous activities in both of the primary afferent terminals (PAT) and motoneurons (MN). These hyperpolarizations were observed even in high-Mg2+ and Ca2+-free Ringer's solution, suggesting that CPC has direct actions on PAT and MN. Various reflex potentials (dorsal and ventral root potentials elicited by stimulating dorsal and ventral root, respectively) tended to be depressed by CPC as well as by mephenesin. Excitatory amino acids (L-aspartic acid and L-glutamic acid) caused marked depolarizations in PAT and MN, and increased the firing rate in MN. CPC did not modify the depolarization but abolished the motoneuron firing induced by these amino acids. However, mephenesin reduced both the depolarization and the motoneuron firing. The dorsal and ventral root potentials evoked by tetanic stimulation (40 Hz) of the dorsal root were depressed by the drugs. These results indicate that CPC has an apparent depressing action on the spinal neuron, and this action may be ascribed to the slight hyperpolarization and/or the prolongation of refractory period.

[Expressional change of nitric oxide synthases in dorsal root ganglia of cats after selective dorsal rhizotomy].

PubMed

Qin, Hua-li; Zhou, Xue; Zhang, Wei; Chen, Si-xiu

2004-01-01

To examine the expressional change of nitric oxide synthase (NOS) in the injured dorsal root ganglia (DRG) and the ipsilateral adjacent uninjured DRG after selective dorsal rhizotomy. Immunochemical ABC method was used to detect the distribution of immunoreaction complex of NOS isoforms--nNOS and eNOS, and quantitative analysis was conducted to get the number of nNOS-immunoreactivity (nNOS-IR) neurons in normal DRG, dorsal rhizotomized DRG and spared DRG from adult cats on the 6th day after operation. This operating model was made by rhizotomizing unilateral L1-L5 dorsal roots and leaving L6 as a spared root. nNOS-immunoreactants were mainly distributed in the small-sized neurons in the DRG of cat. The percentage of nNOS-expressing small-sized neurons increased in the deafferentated L5 DRG (29.74%) when compared with the contralateral DRG (19.35%), and it also increased in the spared DRG (24.22%), compared with the contralateral DRG (18.61%). eNOS-IR was not observed in the DRG of adult cats. nNOS/NO up-regulated in DRG neurons is involved in a wide variety of biological functions under physiological and lesion-induced pathophysiological conditions in nerve system.

Neuronal somatic ATP release triggers neuron–satellite glial cell communication in dorsal root ganglia

PubMed Central

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

2007-01-01

It has been generally assumed that the cell body (soma) of a neuron, which contains the nucleus, is mainly responsible for synthesis of macromolecules and has a limited role in cell-to-cell communication. Using sniffer patch recordings, we show here that electrical stimulation of dorsal root ganglion (DRG) neurons elicits robust vesicular ATP release from their somata. The rate of release events increases with the frequency of nerve stimulation; external Ca2+ entry is required for the release. FM1–43 photoconversion analysis further reveals that small clear vesicles participate in exocytosis. In addition, the released ATP activates P2X7 receptors in satellite cells that enwrap each DRG neuron and triggers the communication between neuronal somata and glial cells. Blocking L-type Ca2+ channels completely eliminates the neuron–glia communication. We further show that activation of P2X7 receptors can lead to the release of tumor necrosis factor-α (TNFα) from satellite cells. TNFα in turn potentiates the P2X3 receptor-mediated responses and increases the excitability of DRG neurons. This study provides strong evidence that somata of DRG neurons actively release transmitters and play a crucial role in bidirectional communication between neurons and surrounding satellite glial cells. These results also suggest that, contrary to the conventional view, neuronal somata have a significant role in cell–cell signaling. PMID:17525149

The effects of ropivacaine hydrochloride on the expression of CaMK II mRNA in the dorsal root ganglion neurons.

PubMed

Wen, Xianjie; Lai, Xiaohong; Li, Xiaohong; Zhang, Tao; Liang, Hua

2016-12-01

In this study, we identified the subtype of Calcium/calmodulin-dependent protein kinase II (CaMK II) mRNA in dorsal root ganglion neurons and observed the effects of ropivacaine hydrochloride in different concentration and different exposure time on the mRNA expression. Dorsal root ganglion neurons were isolated from the SD rats and cultured in vitro. The mRNA of the CaMK II subtype in dorsal root ganglion neurons were detected by real-time PCR. As well as, the dorsal root ganglion neurons were treated with ropivacaine hydrochloride in different concentration (1mM,2mM, 3mM and 4mM) for the same exposure time of 4h, or different exposure time (0h,2h,3h,4h and 6h) at the same concentration(3mM). The changes of the mRNA expression of the CaMK II subtype were observed with real-time PCR. All subtype mRNA of the CaMK II, CaMK II α , CaMK II β , CaMK II δ , CaMK II γ , can be detected in dorsal root ganglion neurons. With the increased of the concentration and exposure time of the ropivacaine hydrochloride, all the subtype mRNA expression increased. Ropivacaine hydrochloride up-regulate the CaMK II β , CaMK II δ , CaMK II g mRNA expression with the concentration and exposure time increasing. The nerve blocking or the neurotoxicity of the ropivacaine hydrochloride maybe involved with CaMK II. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Central vs. peripheral neuraxial sympathetic control of porcine ventricular electrophysiology

PubMed Central

Yamakawa, Kentaro; Howard-Quijano, Kimberly; Zhou, Wei; Rajendran, Pradeep; Yagishita, Daigo; Vaseghi, Marmar; Ajijola, Olujimi A.; Armour, J. Andrew; Shivkumar, Kalyanam; Ardell, Jeffrey L.

2015-01-01

Sympathoexcitation is associated with ventricular arrhythmogenesis. The aim of this study was to determine the role of thoracic dorsal root afferent neural inputs to the spinal cord in modulating ventricular sympathetic control of normal heart electrophysiology. We hypothesize that dorsal root afferent input tonically modulates basal and evoked efferent sympathetic control of the heart. A 56-electrode sock placed on the epicardial ventricle in anesthetized Yorkshire pigs (n = 17) recorded electrophysiological function, as well as activation recovery interval (ARI) and dispersion in ARI, at baseline conditions and during stellate ganglion electrical stimulation. Measures were compared between intact states and sequential unilateral T1–T4 dorsal root transection (DRTx), ipsilateral ventral root transection (VRTx), and contralateral dorsal and ventral root transections (DVRTx). Left or right DRTx decreased global basal ARI [Lt.DRTx: 369 ± 12 to 319 ± 13 ms (P < 0.01) and Rt.DRTx: 388 ± 19 to 356 ± 15 ms (P < 0.01)]. Subsequent unilateral VRTx followed by contralateral DRx+VRTx induced no further change. In intact states, left and right stellate ganglion stimulation shortened ARIs (6 ± 2% vs. 17 ± 3%), while increasing dispersion (+139% vs. +88%). There was no difference in magnitude of ARI or dispersion change with stellate stimulation following spinal root transections. Interruption of thoracic spinal afferent signaling results in enhanced basal cardiac sympathoexcitability without diminishing the sympathetic response to stellate ganglion stimulation. This suggests spinal dorsal root transection releases spinal cord-mediated tonic inhibitory control of efferent sympathetic tone, while maintaining intrathoracic cardiocentric neural networks. PMID:26661096

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.

Limits to the capacity of transplants of olfactory glia to promote axonal regrowth in the CNS.

PubMed

Gudiño-Cabrera, G; Pastor, A M; de la Cruz, R R; Delgado-García, J M; Nieto-Sampedro, M

2000-02-28

Olfactory bulb ensheathing cell (OBEC) transplants promoted axonal regeneration in the spinal cord dorsal root entry zone and in the corticospinal tract. However, OBECs failed to promote abducens internuclear neuron axon regeneration when transplanted at the site of nerve fibre transection. In experiments performed in both cats and rats, OBECs survived for up to 2 months, lining themselves up along the portion of the regrowing axons proximal to the interneuron cell body. However, OBECs migrated preferentially towards abducens somata, in the direction opposite to the oculomotor nucleus target. OBECs seem to promote nerve fibre regeneration only where preferred direction of glial migration coincides with the direction of axonal growth towards its target.

Differences in individual susceptibility affect the development of trigeminal neuralgia☆

PubMed Central

Duransoy, Yusuf Kurtuluş; Mete, Mesut; Akçay, Emrah; Selçuki, Mehmet

2013-01-01

Trigeminal neuralgia is a syndrome due to dysfunctional hyperactivity of the trigeminal nerve, and is characterized by a sudden, usually unilateral, recurrent lancinating pain arising from one or more divisions of the nerve. The most accepted pathogenetic mechanism for trigeminal neuralgia is compression of the nerve at its dorsal root entry zone or in its distal course. In this paper, we report four cases with trigeminal neuralgia due to an unknown mechanism after an intracranial intervention. The onset of trigeminal neuralgia after surgical interventions that are unrelated to the trigeminal nerve suggests that in patients with greater individual susceptibility, nerve contact with the vascular structure due to postoperative pressure and changes in cerebrospinal fluid flow may cause the onset of pain. PMID:25206428

Occipital Neuralgia from C2 Cavernous Malformation

PubMed Central

Ha, Sang-woo; Choi, Jin-gyu; Son, Byung-chul

2018-01-01

A unique case is presented of chronic occipital neuralgia (ON) caused by cavernous malformation (CM) in the intramedullary C2 spinal cord and subsequent pain relief and remodeling of allodynic pain following dorsal root rhizotomy. A 53-year-old male presented with a 30-year history of chronic allodynic, paroxysmal lancinating pain in the greater and lesser occipital nerves. Typically, the pain was aggravated with neck extension and head movement. Magnetic resonance imaging showed a CM in the right posterolateral side of the intramedullary C2 cord. Considering potential risks associated with removal of the lesion, intradural C1-3 dorsal root rhizotomy with dentate ligament resection was performed. The paroxysmal lancinating pain of ON was significantly alleviated, and the remodeling of the extent of allodynic pain was noted after C1-3 dorsal root rhizotomy. These changes gradually occurred during the second postoperative month, and this effect was maintained for 24 months postoperatively. Significant reduction in chronic allodynic pain of secondary ON caused by cervicomedullary CM involving central sensitization in the trigeminocervical complex was observed with reduction of irritating, afferent input with C1-C3 dorsal root rhizotomy. PMID:29682056

Occipital Neuralgia from C2 Cavernous Malformation.

PubMed

Ha, Sang-Woo; Choi, Jin-Gyu; Son, Byung-Chul

2018-01-01

A unique case is presented of chronic occipital neuralgia (ON) caused by cavernous malformation (CM) in the intramedullary C2 spinal cord and subsequent pain relief and remodeling of allodynic pain following dorsal root rhizotomy. A 53-year-old male presented with a 30-year history of chronic allodynic, paroxysmal lancinating pain in the greater and lesser occipital nerves. Typically, the pain was aggravated with neck extension and head movement. Magnetic resonance imaging showed a CM in the right posterolateral side of the intramedullary C2 cord. Considering potential risks associated with removal of the lesion, intradural C1-3 dorsal root rhizotomy with dentate ligament resection was performed. The paroxysmal lancinating pain of ON was significantly alleviated, and the remodeling of the extent of allodynic pain was noted after C1-3 dorsal root rhizotomy. These changes gradually occurred during the second postoperative month, and this effect was maintained for 24 months postoperatively. Significant reduction in chronic allodynic pain of secondary ON caused by cervicomedullary CM involving central sensitization in the trigeminocervical complex was observed with reduction of irritating, afferent input with C1-C3 dorsal root rhizotomy.

Changes in compressed neurons from dogs with acute and severe cauda equina constrictions following intrathecal injection of brain-derived neurotrophic factor-conjugated polymer nanoparticles☆

PubMed Central

Tan, Junming; Shi, Jiangang; Shi, Guodong; Liu, Yanling; Liu, Xiaohong; Wang, Chaoyang; Chen, Dechun; Xing, Shunming; Shen, Lianbing; Jia, Lianshun; Ye, Xiaojian; He, Hailong; Li, Jiashun

2013-01-01

This study established a dog model of acute multiple cauda equina constriction by experimental constriction injury (48 hours) of the lumbosacral central processes in dorsal root ganglia neurons. The repair effect of intrathecal injection of brain-derived neurotrophic factor with 15 mg encapsulated biodegradable poly(lactide-co-glycolide) nanoparticles on this injury was then analyzed. Dorsal root ganglion cells (L7) of all experimental dogs were analyzed using hematoxylin-eosin staining and immunohistochemistry at 1, 2 and 4 weeks following model induction. Intrathecal injection of brain-derived neurotrophic factor can relieve degeneration and inflammation, and elevate the expression of brain-derived neurotrophic factor in sensory neurons of compressed dorsal root ganglion. Simultaneously, intrathecal injection of brain-derived neurotrophic factor obviously improved neurological function in the dog model of acute multiple cauda equina constriction. Results verified that sustained intraspinal delivery of brain-derived neurotrophic factor encapsulated in biodegradable nanoparticles promoted the repair of histomorphology and function of neurons within the dorsal root ganglia in dogs with acute and severe cauda equina syndrome. PMID:25206593

Critical evaluation of the expression of gastrin-releasing peptide in dorsal root ganglia and spinal cord

PubMed Central

Barry, Devin M; Li, Hui; Liu, Xian-Yu; Shen, Kai-Feng; Liu, Xue-Ting; Wu, Zhen-Yu; Munanairi, Admire; Chen, Xiao-Jun; Yin, Jun; Sun, Yan-Gang; Li, Yun-Qing

2016-01-01

There are substantial disagreements about the expression of gastrin-releasing peptide (GRP) in sensory neurons and whether GRP antibody cross-reacts with substance P (SP). These concerns necessitate a critical revaluation of GRP expression using additional approaches. Here, we show that a widely used GRP antibody specifically recognizes GRP but not SP. In the spinal cord of mice lacking SP (Tac1 KO), the expression of not only GRP but also other peptides, notably neuropeptide Y (NPY), is significantly diminished. We detected Grp mRNA in dorsal root ganglias using reverse transcription polymerase chain reaction, in situ hybridization and RNA-seq. We demonstrated that Grp mRNA and protein are upregulated in dorsal root ganglias, but not in the spinal cord, of mice with chronic itch. Few GRP+ immunostaining signals were detected in spinal sections following dorsal rhizotomy and GRP+ cell bodies were not detected in dissociated dorsal horn neurons. Ultrastructural analysis further shows that substantially more GRPergic fibers form synaptic contacts with gastrin releasing peptide receptor-positive (GRPR+) neurons than SPergic fibers. Our comprehensive study demonstrates that a majority of GRPergic fibers are of primary afferent origin. A number of factors such as low copy number of Grp transcripts, small percentage of cells expressing Grp, and the use of an eGFP GENSAT transgenic as a surrogate for GRP protein have contributed to the controversy. Optimization of experimental procedures facilitates the specific detection of GRP expression in dorsal root ganglia neurons. PMID:27068287

A novel chondroitin sulfate hydrogel for nerve repair

NASA Astrophysics Data System (ADS)

Conovaloff, Aaron William

Brachial plexus injuries affect numerous patients every year, with very debilitating results. The majority of these cases are very severe, and involve damage to the nerve roots. To date, repair strategies for these injuries address only gross tissue damage, but do not supply cells with adequate regeneration signals. As a result, functional recovery is often severely lacking. Therefore, a chondroitin sulfate hydrogel that delivers neurotrophic signals to damaged neurons is proposed as a scaffold to support nerve root regeneration. Capillary electrophoresis studies revealed that chondroitin sulfate can physically bind with a variety of neurotrophic factors, and cultures of chick dorsal root ganglia demonstrated robust neurite outgrowth in chondroitin sulfate hydrogels. Outgrowth in chondroitin sulfate gels was greater than that observed in control gels of hyaluronic acid. Furthermore, the chondroitin sulfate hydrogel's binding activity with nerve growth factor could be enhanced by incorporation of a synthetic bioactive peptide, as revealed by fluorescence recovery after photobleaching. This enhanced binding was observed only in chondroitin sulfate gels, and not in hyaluronic acid control gels. This enhanced binding activity resulted in enhanced dorsal root ganglion neurite outgrowth in chondroitin sulfate gels. Finally, the growth of regenerating dorsal root ganglia in these gels was imaged using label-free coherent anti-Stokes scattering microscopy. This technique generated detailed, high-quality images of live dorsal root ganglion neurites, which were comparable to fixed, F-actin-stained samples. Taken together, these results demonstrate the viability of this chondroitin sulfate hydrogel to serve as an effective implantable scaffold to aid in nerve root regeneration.

Infrared neural stimulation of human spinal nerve roots in vivo.

PubMed

Cayce, Jonathan M; Wells, Jonathon D; Malphrus, Jonathan D; Kao, Chris; Thomsen, Sharon; Tulipan, Noel B; Konrad, Peter E; Jansen, E Duco; Mahadevan-Jansen, Anita

2015-01-01

Infrared neural stimulation (INS) is a neurostimulation modality that uses pulsed infrared light to evoke artifact-free, spatially precise neural activity with a noncontact interface; however, the technique has not been demonstrated in humans. The objective of this study is to demonstrate the safety and efficacy of INS in humans in vivo. The feasibility of INS in humans was assessed in patients ([Formula: see text]) undergoing selective dorsal root rhizotomy, where hyperactive dorsal roots, identified for transection, were stimulated in vivo with INS on two to three sites per nerve with electromyogram recordings acquired throughout the stimulation. The stimulated dorsal root was removed and histology was performed to determine thermal damage thresholds of INS. Threshold activation of human dorsal rootlets occurred in 63% of nerves for radiant exposures between 0.53 and [Formula: see text]. In all cases, only one or two monitored muscle groups were activated from INS stimulation of a hyperactive spinal root identified by electrical stimulation. Thermal damage was first noted at [Formula: see text] and a [Formula: see text] safety ratio was identified. These findings demonstrate the success of INS as a fresh approach for activating human nerves in vivo and providing the necessary safety data needed to pursue clinically driven therapeutic and diagnostic applications of INS in humans.

Neurotization of elements of the brachial plexus.

PubMed

Friedman, A H

1991-01-01

Satisfactory therapy for an avulsion injury of the brachial plexus has yet to be described. Dorsal root entry zone lesions will usually mitigate the searing pain which is so disabling in some of these patients. Neurotization procedures are effective in restoring limited function to these patients. The most useful isolated movement of the upper extremity is elbow flexion, which is thus the primary target of neurotization procedures. Intercostal nerves and elements of the cervical plexus are the most commonly used donor nerves for neurotization procedures. From our experience and from a review of the literature, it appears that these procedures will be successful in approximately 50% of cases. It must be stressed that before performing a nerve transfer, the surgeon must be certain that the patient is not a candidate for a simple nerve graft.

Infrared neural stimulation of human spinal nerve roots in vivo

PubMed Central

Cayce, Jonathan M.; Wells, Jonathon D.; Malphrus, Jonathan D.; Kao, Chris; Thomsen, Sharon; Tulipan, Noel B.; Konrad, Peter E.; Jansen, E. Duco; Mahadevan-Jansen, Anita

2015-01-01

Abstract. Infrared neural stimulation (INS) is a neurostimulation modality that uses pulsed infrared light to evoke artifact-free, spatially precise neural activity with a noncontact interface; however, the technique has not been demonstrated in humans. The objective of this study is to demonstrate the safety and efficacy of INS in humans in vivo. The feasibility of INS in humans was assessed in patients (n=7) undergoing selective dorsal root rhizotomy, where hyperactive dorsal roots, identified for transection, were stimulated in vivo with INS on two to three sites per nerve with electromyogram recordings acquired throughout the stimulation. The stimulated dorsal root was removed and histology was performed to determine thermal damage thresholds of INS. Threshold activation of human dorsal rootlets occurred in 63% of nerves for radiant exposures between 0.53 and 1.23  J/cm2. In all cases, only one or two monitored muscle groups were activated from INS stimulation of a hyperactive spinal root identified by electrical stimulation. Thermal damage was first noted at 1.09  J/cm2 and a 2∶1 safety ratio was identified. These findings demonstrate the success of INS as a fresh approach for activating human nerves in vivo and providing the necessary safety data needed to pursue clinically driven therapeutic and diagnostic applications of INS in humans. PMID:26157986

The stress protein heat shock cognate 70 (Hsc70) inhibits the Transient Receptor Potential Vanilloid type 1 (TRPV1) channel.

PubMed

Iftinca, Mircea; Flynn, Robyn; Basso, Lilian; Melo, Helvira; Aboushousha, Reem; Taylor, Lauren; Altier, Christophe

2016-01-01

Specialized cellular defense mechanisms prevent damage from chemical, biological, and physical hazards. The heat shock proteins have been recognized as key chaperones that maintain cell survival against a variety of exogenous and endogenous stress signals including noxious temperature. However, the role of heat shock proteins in nociception remains poorly understood. We carried out an expression analysis of the constitutively expressed 70 kDa heat-shock cognate protein, a member of the stress-induced HSP70 family in lumbar dorsal root ganglia from a mouse model of Complete Freund's Adjuvant-induced chronic inflammatory pain. We used immunolabeling of dorsal root ganglion neurons, behavioral analysis and patch clamp electrophysiology in both dorsal root ganglion neurons and HEK cells transfected with Hsc70 and Transient Receptor Potential Channels to examine their functional interaction in heat shock stress condition. We report an increase in protein levels of Hsc70 in mouse dorsal root ganglia, 3 days post Complete Freund's Adjuvant injection in the hind paw. Immunostaining of Hsc70 was observed in most of the dorsal root ganglion neurons, including the small size nociceptors immunoreactive to the TRPV1 channel. Standard whole-cell patch-clamp technique was used to record Transient Receptor Potential Vanilloid type 1 current after exposure to heat shock. We found that capsaicin-evoked currents are inhibited by heat shock in dorsal root ganglion neurons and transfected HEK cells expressing Hsc70 and TRPV1. Blocking Hsc70 with matrine or spergualin compounds prevented heat shock-induced inhibition of the channel. We also found that, in contrast to TRPV1, both the cold sensor channels TRPA1 and TRPM8 were unresponsive to heat shock stress. Finally, we show that inhibition of TRPV1 depends on the ATPase activity of Hsc70 and involves the rho-associated protein kinase. Our work identified Hsc70 and its ATPase activity as a central cofactor of TRPV1 channel function and points to the role of this stress protein in pain associated with neurodegenerative and/or metabolic disorders, including aging. © The Author(s) 2016.

Pathological lesions in the central nervous system and peripheral tissues of ddY mice with street rabies virus (1088 strain).

PubMed

Kimitsuki, Kazunori; Yamada, Kentaro; Shiwa, Nozomi; Inoue, Satoshi; Nishizono, Akira; Park, Chun-Ho

2017-06-10

Most studies on rabies virus pathogenesis in animal models have employed fixed rabies viruses, and the results of those employing street rabies viruses have been inconsistent. Therefore, to clarify the pathogenesis of street rabies virus (1088 strain) in mice, 10 6 focus forming units were inoculated into the right hindlimb of ddY mice (6 weeks, female). At 3 days postinoculation (DPI), mild inflammation was observed in the hindlimb muscle. At 5 DPI, ganglion cells in the right lumbosacral spinal dorsal root ganglia showed chromatolysis. Axonal degeneration and inflammatory cells increased with infection progress in the spinal dorsal horn and dorsal root ganglia. Right hindlimb paralysis was observed from 7 DPI, which progressed to quadriparalysis. However, no pathological changes were observed in the ventral horn and root fibers of the spinal cord. Viral antigen was first detected in the right hindlimb muscle at 3 DPI, followed by the right lumbosacral dorsal root ganglia, dorsal horn of spinal cord, left red nuclei, medulla oblongata and cerebral cortex (M1 area) at 5 DPI. These results suggested that the 1088 virus ascended the lumbosacral spinal cord via mainly afferent fibers at early stage of infection and moved to cerebral cortex (M1 area) using descending spinal tract. Additionally, we concluded that significant pathological changes in mice infected with 1088 strain occur in the sensory tract of the spinal cord; this selective susceptibility results in clinical features of the disease.

Synaptic plasticity and sensory-motor improvement following fibrin sealant dorsal root reimplantation and mononuclear cell therapy

PubMed Central

Benitez, Suzana U.; Barbizan, Roberta; Spejo, Aline B.; Ferreira, Rui S.; Barraviera, Benedito; Góes, Alfredo M.; de Oliveira, Alexandre L. R.

2014-01-01

Root lesions may affect both dorsal and ventral roots. However, due to the possibility of generating further inflammation and neuropathic pain, surgical procedures do not prioritize the repair of the afferent component. The loss of such sensorial input directly disturbs the spinal circuits thus affecting the functionality of the injuried limb. The present study evaluated the motor and sensory improvement following dorsal root reimplantation with fibrin sealant (FS) plus bone marrow mononuclear cells (MC) after dorsal rhizotomy. MC were used to enhance the repair process. We also analyzed changes in the glial response and synaptic circuits within the spinal cord. Female Lewis rats (6–8 weeks old) were divided in three groups: rhizotomy (RZ group), rhizotomy repaired with FS (RZ+FS group) and rhizotomy repaired with FS and MC (RZ+FS+MC group). The behavioral tests electronic von-Frey and Walking track test were carried out. For immunohistochemistry we used markers to detect different synapse profiles as well as glial reaction. The behavioral results showed a significant decrease in sensory and motor function after lesion. The reimplantation decreased glial reaction and improved synaptic plasticity of afferent inputs. Cell therapy further enhanced the rewiring process. In addition, both reimplanted groups presented twice as much motor control compared to the non-treated group. In conclusion, the reimplantation with FS and MC is efficient and may be considered an approach to improve sensory-motor recovery following dorsal rhizotomy. PMID:25249946

Up-regulation of CXCR4 expression contributes to persistent abdominal pain in rats with chronic pancreatitis.

PubMed

Zhu, Hong-Yan; Liu, Xuelian; Miao, Xiuhua; Li, Di; Wang, Shusheng; Xu, Guang-Yin

2017-01-01

Background Pain in patients with chronic pancreatitis is critical hallmark that accompanied inflammation, fibrosis, and destruction of glandular pancreas. Many researchers have demonstrated that stromal cell-derived factor 1 (also named as CXCL12) and its cognate receptor C-X-C chemokine receptor type 4 (CXCR4) involved in mediating neuropathic and bone cancer pain. However, their roles in chronic pancreatic pain remain largely unclear. Methods Chronic pancreatitis was induced by intraductal injection of trinitrobenzene sulfonic acid to the pancreas. Von Frey filament tests were conducted to evaluate pancreas hypersensitivity of rat. Expression of CXCL12, CXCR4, NaV1.8, and pERK in rat dorsal root ganglion was detected by Western blot analyses. Dorsal root ganglion neuronal excitability was assessed by electrophysiological recordings. Results We showed that both CXCL12 and CXCR4 were dramatically up-regulated in the dorsal root ganglion in trinitrobenzene sulfonic acid-induced chronic pancreatitis pain model. Intrathecal application with AMD3100, a potent and selective CXCR4 inhibitor, reversed the hyperexcitability of dorsal root ganglion neurons innervating the pancreas of rats following trinitrobenzene sulfonic acid injection. Furthermore, trinitrobenzene sulfonic acid-induced extracellular signal-regulated kinase activation and Nav1.8 up-regulation in dorsal root ganglias were reversed by intrathecal application with AMD3100 as well as by blockade of extracellular signal-regulated kinase activation by intrathecal U0126. More importantly, the trinitrobenzene sulfonic acid-induced persistent pain was significantly suppressed by CXCR4 and extracellular signal-regulated kinase inhibitors. Conclusions The present results suggest that the activation of CXCL12-CXCR4 signaling might contribute to pancreatic pain and that extracellular signal-regulated kinase-dependent Nav1.8 up-regulation might lead to hyperexcitability of the primary nociceptor neurons in rats with chronic pancreatitis.

Spinal cord injury below-level neuropathic pain relief with dorsal root entry zone microcoagulation performed caudal to level of complete spinal cord transection.

PubMed

Falci, Scott; Indeck, Charlotte; Barnkow, Dave

2018-06-01

OBJECTIVE Surgically created lesions of the spinal cord dorsal root entry zone (DREZ) to relieve central pain after spinal cord injury (SCI) have historically been performed at and cephalad to, but not below, the level of SCI. This study was initiated to investigate the validity of 3 proposed concepts regarding the DREZ in SCI central pain: 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through sympathetic nervous system (SNS) pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain-generators. METHODS Three unique patients with both intractable SCI below-level central pain and complete spinal cord transection at the level of SCI were identified. All 3 patients had previously undergone surgical intervention to their spinal cords-only cephalad to the level of spinal cord transection-with either DREZ microcoagulation or cyst shunting, in failed attempts to relieve their SCI below-level central pain. Subsequent to these surgeries, DREZ lesioning of the spinal cord solely caudal to the level of complete spinal cord transection was performed using electrical intramedullary guidance. The follow-up period ranged from 1 1/2 to 11 years. RESULTS All 3 patients in this study had complete or near-complete relief of all below-level neuropathic pain. The analyzed electrical data confirmed and enhanced a previously proposed somatotopic map of SCI below-level DREZ pain generators. CONCLUSIONS The results of this study support the following hypotheses. 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through SNS pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain generators.

[Long-term effects of pulsed radiofrequency on the dorsal root ganglion and segmental nerve roots for lumbosacral radicular pain: a prospective controlled randomized trial with nerve root block].

PubMed

Fujii, Hiromi; Kosogabe, Yoshinori; Kajiki, Hideki

2012-08-01

Although pulsed radiofrequency (PRF) method for lumbosacral radicular pain (LSRP) is reportedly effective, there are no prospective controlled trials. We assessed the long-term efficacy of PRF of the dorsal root ganglion and nerve roots for LSRP as compared with nerve root block (RB). The study included 27 patients suffering from LSRP. The design of this study was randomized with a RB control. In the PRF group, the PRF current was applied for 120 seconds after RB. In the RB group, the patients received RB only. Visual analogue scale (VAS) was assessed immediately before, and immediately, 2 hours, 1 day, 1 week, 1 month, 3 months, 6 months, and 1 year after the procedure. P<0.05 was regarded as denoting statistical significance. In both groups, the VAS not only of short-term but also of long-term (6 months and 1 year after procedure) significantly decreased as compared with that before treatment (P<0.05). There were no significant differences of VAS between the two groups at the same time points. This study indicates that PRF adjacent to the dorsal root ganglion and nerve roots for LSRP has long-term effects. There were no significant differences of long-term effects between the two groups.

Mesenchymal Stem Cells Improve Motor Functions and Decrease Neurodegeneration in Ataxic Mice

PubMed Central

Jones, Jonathan; Estirado, Alicia; Redondo, Carolina; Pacheco-Torres, Jesus; Sirerol-Piquer, Maria-Salomé; Garcia-Verdugo, José M; Martinez, Salvador

2015-01-01

The main objective of this work is to demonstrate the feasibility of using bone marrow-derived stem cells in treating a neurodegenerative disorder such as Friedreich's ataxia. In this disease, the dorsal root ganglia of the spinal cord are the first to degenerate. Two groups of mice were injected intrathecally with mesenchymal stem cells isolated from either wild-type or Fxntm1Mkn/Tg(FXN)YG8Pook (YG8) mice. As a result, both groups presented improved motor skills compared to nontreated mice. Also, frataxin expression was increased in the dorsal root ganglia of the treated groups, along with lower expression of the apoptotic markers analyzed. Furthermore, the injected stem cells expressed the trophic factors NT3, NT4, and BDNF, which bind to sensory neurons of the dorsal root ganglia and increase their survival. The expression of antioxidant enzymes indicated that the stem cell-treated mice presented higher levels of catalase and GPX-1, which are downregulated in the YG8 mice. There were no significant differences in the use of stem cells isolated from wild-type and YG8 mice. In conclusion, bone marrow mesenchymal stem cell transplantation, both autologous and allogeneic, is a feasible therapeutic option to consider in delaying the neurodegeneration observed in the dorsal root ganglia of Friedreich's ataxia patients. PMID:25070719

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.

Inflammation enhances Y1 receptor signaling, neuropeptide Y-mediated inhibition of hyperalgesia, and substance P release from primary afferent neurons

PubMed Central

Taylor, Bradley K.; Fu, Weisi; Kuphal, Karen E.; Stiller, Carl-Olav; Winter, Michelle K.; Chen, Wenling; Corder, Gregory F.; Urban, Janice H.; McCarson, Kenneth E.; Marvizon, Juan Carlos

2014-01-01

Neuropeptide Y (NPY) is present in the superficial laminae of the dorsal horn and inhibits spinal nociceptive processing, but the mechanisms underlying its anti-hyperalgesic actions are unclear. We hypothesized that NPY acts at neuropeptide Y1 receptors in dorsal horn to decrease nociception by inhibiting substance P (SP) release, and that these effects are enhanced by inflammation. To evaluate SP release, we used microdialysis and neurokinin 1 receptor (NK1R) internalization in rat. NPY decreased capsaicin-evoked SP-like immunoreactivity in microdialysate of the dorsal horn. NPY also decreased non-noxious stimulus (paw brush)-evoked NK1R internalization (as well as mechanical hyperalgesia and mechanical and cold allodynia) after intraplantar injection of carrageenan. Similarly, in rat spinal cord slices with dorsal root attached, [Leu31, Pro34]-NPY inhibited dorsal root stimulus-evoked NK1R internalization. In rat dorsal root ganglion neurons, Y1 receptors colocalized extensively with calcitonin gene-related peptide (CGRP). In dorsal horn neurons, Y1 receptors were extensively expressed and this may have masked detection of terminal co-localization with CGRP or SP. To determine whether the pain inhibitory actions of Y1 receptors are enhanced by inflammation, we administered [Leu31, Pro34]-NPY after intraplantar injection of complete Freund's adjuvant (CFA) in rat. We found that [Leu31, Pro34]-NPY reduced paw clamp-induced NK1R internalization in CFA rats but not uninjured controls. To determine the contribution of increased Y1 receptor-G protein coupling, we measured [35S]GTPγS binding simulated by [Leu31, Pro34]-NPY in mouse dorsal horn. CFA inflammation increased the affinity of Y1 receptor G-protein coupling. We conclude that Y1 receptors contribute to the anti-hyperalgesic effects of NPY by mediating inhibition of SP release, and that Y1 receptor signaling in the dorsal horn is enhanced during inflammatory nociception. PMID:24184981

Vascular compression as a potential cause of occipital neuralgia: a case report.

PubMed

White, J B; Atkinson, P P; Cloft, H J; Atkinson, J L D

2008-01-01

Vascular compression is a well-established cause of cranial nerve neuralgic syndromes. A unique case is presented that demonstrates that vascular compression may be a possible cause of occipital neuralgia. A 48-year-old woman with refractory left occipital neuralgia revealed on magnetic resonance imaging and computed tomographic imaging of the upper cervical spine an atypically low loop of the left posterior inferior cerebellar artery (PICA), clearly indenting the dorsal upper cervical roots. During surgery, the PICA loop was interdigitated with the C1 and C2 dorsal roots. Microvascular decompression alone has never been described for occipital neuralgia, despite the strong clinical correlation in this case. Therefore, both sectioning the dorsal roots of C2 and microvascular decompression of the PICA loop were performed. Postoperatively, the patient experienced complete cure of her neuralgia. Vascular compression as a cause of refractory occipital neuralgia should be considered when assessing surgical options.

[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 7th day (P<0.05) and came back to normal level on the 14th day (P>0.05). Partial dorsal root rhizotomy can lead to the change of IGF-I expression in bilateral DRG and Clarke's nucleus, which suggests that IGF-I be related with spinal cord plasticity.

Axotomy increases NADPH-diaphorase activity in the dorsal root ganglia and lumbar spinal cord of the turtle Trachemys dorbigni.

PubMed

Partata, W A; Krepsky, A M; Marques, M; Achaval, M

1999-04-01

Seven days after transection of the sciatic nerve NADPH-diaphorase activity increased in the small and medium neurons of the dorsal root ganglia of the turtle. However, this increase was observed only in medium neurons for up to 90 days. At this time a bilateral increase of NADPH-diaphorase staining was observed in all areas and neuronal types of the dorsal horn, and in positive motoneurons in the lumbar spinal cord, ipsilateral to the lesion. A similar increase was also demonstrable in spinal glial and endothelial cells. These findings are discussed in relation to the role of nitric oxide in hyperalgesia and neuronal regeneration or degeneration.

Substance P release in the spinal cord during the exercise pressor reflex in anaesthetized cats.

PubMed Central

Wilson, L B; Fuchs, I E; Matsukawa, K; Mitchell, J H; Wall, P T

1993-01-01

1. The purpose of this study was to determine if static skeletal muscle contraction causes the release of substance P(SP) in the L7-dorsal horn region of the spinal cord. A laminectomy was performed to expose the spinal cord of alpha-chloralose anaesthetized cats. The L6 spinal root was cut. A microdialysis probe was inserted into the L7 dorsal horn region ipsilateral to the contracting triceps surae muscle. The probe was perfused with a buffer solution at 3 microliters/min. Substance P-like immunoreactivity (SP-LI) was measured, from the microdialysis samples, by radioimmunoassay. 2. A 5-9 min contraction of the triceps surae muscle was evoked by alternate electrical stimulation of the peripheral ends of the cut L7 and S1 ventral roots. Basal SP-LI release was 0.20 +/- 0.03 fmol/100 microliters and was increased to 0.54 +/- 0.05 fmol/100 microliters (mean +/- S.D.) by static muscle contraction. This increase was greatly attenuated after cutting the L7 and S1 dorsal roots (0.23 +/- 0.03 to 0.39 +/- 0.08 fmol/100 microliters) or completely abolished by muscle paralysis (0.27 +/- 0.03 to 0.31 +/- 0.01 fmol/100 microliters). Muscle contraction also increased mean arterial blood pressure (MAP) 29 +/- 20 mmHg and heart rate (HR) 11 +/- 5 beats/min (mean +/- S.D.). These cardiovascular changes to muscle contraction were abolished by sectioning the dorsal roots or when the ventral roots were electrically stimulated after the cats were paralysed. 3. These results demonstrate that static contraction of skeletal muscle increases the release of SP-LI in the dorsal horn of the spinal cord. Furthermore, these data support the hypothesis that SP plays a role in mediating the cardiovascular responses evoked during static exercise. PMID:7683719

[Selective cervical dorsal root cutting off part of the vertebral lateral mass fixation combined with exercise therapy for treating spastic cerebral paralysis of the upper limbs caused by cerebral palsy].

PubMed

Zhang, Peng; Hu, Wei; Cao, Xu; Xu, Shi-gang; Li, De-kui; Xu, Lin

2009-10-01

To explore the feasibility and the result for the surgical treatment of spastic cerebral paralysis of the upper limbs in patients who underwent the selective cervical dorsal root cutting off part of the vertebral lateral mass fixation combined with exercise therapy. From March 2004 to April 2008, 27 patients included 19 boys and 8 girls, aging 13-21 years with an average of 15 years underwent selective cervical dorsal root cutting off part of the vertebral lateral mass fixation with exercise therapy. The AXIS 8 holes titanium plate was inserted into the lateral mass of spinous process through guidance of the nerve stimulator, choosed fasciculus of low-threshold nerve dorsal root and cut off its 1.5 cm. After two weeks, training exercise therapy was done in patients. Training will include lying position, turning body, sitting position, crawling, kneeling and standing position, walking and so on. Spastic Bobath inhibiting abnormal pattern was done in the whole process of training. The muscular tension, motor function (GMFM), functional independence (WeeFIM) were observed after treatment. All patients were followed up from 4 to 16 months with an average of 6 months. Muscular tension score were respectively 3.30 +/- 0.47 and 1.25 +/- 0.44 before and after treatment;GMFM score were respectively 107.82 +/- 55.17 and 131.28 +/- 46.45; WeeFIM score were respectively 57.61 +/- 25.51 and 87.91 +/- 22.39. There was significant improvement before and after treatment (P < 0.01). Selective cervical dorsal root cutting off part of the vertebral lateral mass fixation combined with exercise therapy was used to treat spastic cerebral paralysis of the upper limbs is safe and effective method, which can decrease muscular tension and improve motor function, which deserves more wide use.

Potentiation of substance p by lysergic acid diethylamide in vivo

PubMed Central

Krivoy, W. A.

1961-01-01

In doses of 10 μg/kg or more, lysergic acid diethylamide enhanced the fourth potential (DR IV) of the dorsal root potential complex in the cat. Smaller doses of lysergic acid diethylamide did not in themselves alter the DR IV, but revealed an enhancement of the potential by substance P, which by itself had no effect. 2-Bromolysergic acid diethylamide had no action on the dorsal root potentials, but prevented the actions of lysergic acid diethylamide. PMID:13754427

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.

Dimethylarginine dimethylaminohydrolase 1 is involved in spinal nociceptive plasticity.

PubMed

DʼMello, Richard; Sand, Claire A; Pezet, Sophie; Leiper, James M; Gaurilcikaite, Egle; McMahon, Stephen B; Dickenson, Anthony H; Nandi, Manasi

2015-10-01

Activation of neuronal nitric oxide synthase, and consequent production of nitric oxide (NO), contributes to spinal hyperexcitability and enhanced pain sensation. All NOS isoforms are inhibited endogenously by asymmetric dimethylarginine, which itself is metabolised by dimethylarginine dimethylaminohydrolase (DDAH). Inhibition of DDAH can indirectly attenuate NO production by elevating asymmetric dimethylarginine concentrations. Here, we show that the DDAH-1 isoform is constitutively active in the nervous system, specifically in the spinal dorsal horn. DDAH-1 was found to be expressed in sensory neurons within both the dorsal root ganglia and spinal dorsal horn; L-291 (NG-[2-Methoxyethyl]-L-arginine methyl ester), a DDAH-1 inhibitor, reduced NO synthesis in cultured dorsal root ganglia neurons. Spinal application of L-291 decreased N-methyl-D-aspartate-dependent postdischarge and windup of dorsal horn sensory neurons--2 measures of spinal hyperexcitability. Finally, spinal application of L-291 reduced both neuronal and behavioral measures of formalin-induced central sensitization. Thus, DDAH-1 may be a potential therapeutic target in neuronal disorders, such as chronic pain, where elevated NO is a contributing factor.

The direct connections of the C2 dorsal ganglion in the brain stem of the squirrel monkey: a preliminary investigation *

PubMed Central

Fitz-Ritson, Don E.

1979-01-01

The purpose of this investigation was to observe the possible anatomical connections of C2 dorsal root with brain stem nuclei. Labelled amino acids (leucine, glycine, proline), were injected into the dorsal root of C2 of a squirrel monkey. The animal was allowed to survive for 20 hrs. and after, sections of the spinal cord and brain stem were subjected to autoradiographic methods. Direct connections were observed in Lamina II, VII, VIII of the spinal cord; the hypoglossal nucleus, medial vestibular nucleus, lateral cuneatus nucleus and lateral parvocellular reticular formation. Possible anatomical and physiological correlates are explored in relation to the importance of the upper cervical area and its control mechanisms.

[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/non-operrtion non-Acup side of DRG.

A curative treatment option for Complex Regional Pain Syndrome (CRPS) Type I: dorsal root entry zone operation (report of two cases).

PubMed

Kanpolat, Yucel; Al-Beyati, Eyyub; Ugur, Hasan Caglar; Akpinar, Gokhan; Kahilogullari, Gokmen; Bozkurt, Melih

2014-01-01

Complex Regional Pain Syndrome Type I (CRPS-I) is a debated health problem concerning its pathophysiology and treatment strategies. A 12-year-old boy and a 35-year-old woman were diagnosed with CRPS-I at different times. They had previously undergone various types of interventions with no success. After one year of follow-up and observation, DREZ lesioning operation was performed. Afterwards, both cases had transient lower extremity ataxia. The first case was followed for 60 months with no recurrence and total cure. The second case was pain-free until the 6th month, when she required psychological support; she was followed for 33 months with partial satisfactory outcome. Although not a first-line option, DREZ lesioning procedure can be chosen and may be a curative option in selected cases of CRPS-I who are unresponsive to conventional therapies.

The anti-nociceptive agent ralfinamide inhibits tetrodotoxin-resistant and tetrodotoxin-sensitive Na+ currents in dorsal root ganglion neurons.

PubMed

Stummann, Tina C; Salvati, Patricia; Fariello, Ruggero G; Faravelli, Laura

2005-03-14

Tetrodotoxin-resistant and tetrodotoxin-sensitive Na+ channels contribute to the abnormal spontaneous firing in dorsal root ganglion neurons associated with neuropathic pain. Effects of the anti-nociceptive agent ralfinamide on tetrodotoxin-resistant and tetrodotoxin-sensitive currents in rat dorsal root ganglion neurons were therefore investigated by patch clamp experiments. Ralfinamide inhibition was voltage-dependent showing highest potency towards inactivated channels. IC50 values for tonic block of half-maximal inactivated tetrodotoxin-resistant and tetrodotoxin-sensitive currents were 10 microM and 22 microM. Carbamazepine, an anticonvulsant used in the treatment of pain, showed significantly lower potency. Ralfinamide produced a hyperpolarising shift in the steady-state inactivation curves of both currents confirming the preferential interaction with inactivated channels. Additionally, ralfinamide use and frequency dependently inhibited both currents and significantly delayed repriming from inactivation. All effects were more pronounced for tetrodotoxin-resistant than tetrodotoxin-sensitive currents. The potency and mechanisms of actions of ralfinamide provide a hypothesis for the anti-nociceptive properties found in animal models.

Response of cervicogenic headaches and occipital neuralgia to radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve.

PubMed

Hamer, John F; Purath, Traci A

2014-03-01

This article investigates the degree and duration of pain relief from cervicogenic headaches or occipital neuralgia following treatment with radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. It also addresses the procedure's complication rate and patient's willingness to repeat the procedure if severe symptoms recur. This is a single-center retrospective observational study of 40 patients with refractory cervicogenic headaches and or occipital neuralgia. Patients were all referred by a headache specialty clinic for evaluation for radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerves. After treatment, patients were followed for a minimum of 6 months to a year. Patient demographics and the results of radiofrequency ablation were recorded on the same day, after 3-4 days, and at 6 months to 1 year following treatment. Thirty-five percent of patients reported 100% pain relief and 70% reported 80% or greater pain relief. The mean duration of improvement is 22.35 weeks. Complication rate was 12-13%. 92.5% of patients reported they would undergo the procedure again if severe symptoms returned. Radiofrequency ablation of the C2 dorsal root ganglion and/or third occipital nerve can provide many months of greater than 50% pain relief in the vast majority of recipients with an expected length of symptom improvement of 5-6 months. © 2014 American Headache Society.

Permeation and block of TRPV1 channels by the cationic lidocaine derivative QX-314

PubMed Central

Puopolo, Michelino; Binshtok, Alexander M.; Yao, Gui-Lan; Oh, Seog Bae; Woolf, Clifford J.

2013-01-01

QX-314 (N-ethyl-lidocaine) is a cationic lidocaine derivative that blocks voltage-dependent sodium channels when applied internally to axons or neuronal cell bodies. Coapplication of external QX-314 with the transient receptor potential vanilloid 1 protein (TRPV1) agonist capsaicin produces long-lasting sodium channel inhibition in TRPV1-expressing neurons, suggestive of QX-314 entry into the neurons. We asked whether QX-314 entry occurs directly through TRPV1 channels or through a different pathway (e.g., pannexin channels) activated downstream of TRPV1 and whether QX-314 entry requires the phenomenon of “pore dilation” previously reported for TRPV1. With external solutions containing 10 or 20 mM QX-314 as the only cation, inward currents were activated by stimulation of both heterologously expressed and native TRPV1 channels in rat dorsal root ganglion neurons. QX-314-mediated inward current did not require pore dilation, as it activated within several seconds and in parallel with Cs-mediated outward current, with a reversal potential consistent with PQX-314/PCs = 0.12. QX-314-mediated current was no different when TRPV1 channels were expressed in C6 glioma cells, which lack expression of pannexin channels. Rapid addition of QX-314 to physiological external solutions produced instant partial inhibition of inward currents carried by sodium ions, suggesting that QX-314 is a permeant blocker. Maintained coapplication of QX-314 with capsaicin produced slowly developing reduction of outward currents carried by internal Cs, consistent with intracellular accumulation of QX-314 to concentrations of 50–100 μM. We conclude that QX-314 is directly permeant in the “standard” pore formed by TRPV1 channels and does not require either pore dilation or activation of additional downstream channels for entry. PMID:23303863

Bupivacaine-induced cellular entry of QX-314 and its contribution to differential nerve block

PubMed Central

Brenneis, C; Kistner, K; Puopolo, M; Jo, S; Roberson, DP; Sisignano, M; Segal, D; Cobos, EJ; Wainger, BJ; Labocha, S; Ferreirós, N; Hehn, C; Tran, J; Geisslinger, G; Reeh, PW; Bean, BP; Woolf, C J

2014-01-01

Background and Purpose: Selective nociceptor fibre block is achieved by introducing the cell membrane impermeant sodium channel blocker lidocaine N-ethyl bromide (QX-314) through transient receptor potential V1 (TRPV1) channels into nociceptors. We screened local anaesthetics for their capacity to activate TRP channels, and characterized the nerve block obtained by combination with QX-314. Experimental Approach: We investigated TRP channel activation in dorsal root ganglion (DRG) neurons by calcium imaging and patch-clamp recordings, and cellular QX-314 uptake by MS. To characterize nerve block, compound action potential (CAP) recordings from isolated nerves and behavioural responses were analysed. Key Results: Of the 12 compounds tested, bupivacaine was the most potent activator of ruthenium red-sensitive calcium entry in DRG neurons and activated heterologously expressed TRPA1 channels. QX-314 permeated through TRPA1 channels and accumulated intracellularly after activation of these channels. Upon sciatic injections, QX-314 markedly prolonged bupivacaine's nociceptive block and also extended (to a lesser degree) its motor block. Bupivacaine's blockade of C-, but not A-fibre, CAPs in sciatic nerves was extended by co-application of QX-314. Surprisingly, however, this action was the same in wild-type, TRPA1-knockout and TRPV1/TRPA1-double knockout mice, suggesting a TRP-channel independent entry pathway. Consistent with this, high doses of bupivacaine promoted a non-selective, cellular uptake of QX-314. Conclusions and Implications: Bupivacaine, combined with QX-314, produced a long-lasting sensory nerve block. This did not require QX-314 permeation through TRPA1, although bupivacaine activated these channels. Regardless of entry pathway, the greatly extended duration of block produced by QX-314 and bupivacaine may be clinically useful. PMID:24117225

Long-term outcomes of intradural cervical dorsal root rhizotomy for refractory occipital neuralgia.

PubMed

Gande, Abhiram V; Chivukula, Srinivas; Moossy, John J; Rothfus, William; Agarwal, Vikas; Horowitz, Michael B; Gardner, Paul A

2016-07-01

OBJECT Occipital neuralgia (ON) causes chronic pain in the cutaneous distribution of the greater and lesser occipital nerves. The long-term efficacy of cervical dorsal root rhizotomy (CDR) in the management of ON has not been well described. The authors reviewed their 14-year experience with CDR to assess pain relief and functional outcomes in patients with medically refractory ON. METHODS A retrospective chart review of 75 ON patients who underwent cervical dorsal root rhizotomy, from 1998 to 2012, was performed. Fifty-five patients were included because they met the International Headache Society's (IHS) diagnostic criteria for ON, responded to CT-guided nerve blocks at the C-2 dorsal nerve root, and had at least one follow-up visit. Telephone interviews were additionally used to obtain data on patient satisfaction. RESULTS Forty-two patients (76%) were female, and the average age at surgery was 46 years (range 16-80). Average follow up was 67 months (range 5-150). Etiologies of ON included the following: idiopathic (44%), posttraumatic (27%), postsurgical (22%), post-cerebrovascular accident (4%), postherpetic (2%), and postviral (2%). At last follow-up, 35 patients (64%) reported full pain relief, 11 (20%) partial relief, and 7 (16%) no pain relief. The extent of pain relief after CDR was not significantly associated with ON etiology (p = 0.43). Of 37 patients whose satisfaction-related data were obtained, 25 (68%) reported willingness to undergo repeat surgery for similar pain relief, while 11 (30%) reported no such willingness; a single patient (2%) did not answer this question. Twenty-one individuals (57%) reported that their activity level/functional state improved after surgery, 5 (13%) reported a decline, and 11 (30%) reported no difference. The most common acute postoperative complications were infections in 9% (n = 5) and CSF leaks in 5% (n = 3); chronic complications included neck pain/stiffness in 16% (n = 9) and upper-extremity symptoms in 5% (n = 3) such as trapezius weakness, shoulder pain, and arm paresthesias. CONCLUSIONS Cervical dorsal root rhizotomy provides an efficacious means for pain relief in patients with medically refractory ON. In the appropriately selected patient, it may lead to optimal outcomes with a relatively low risk of complications.

Blockade of Nogo Receptor Ligands Promotes Functional Regeneration of Sensory Axons After Dorsal Root Crush

PubMed Central

Harvey, Pamela A.; Lee, Daniel H.S.; Qian, Fang; Weinreb, Paul H.; Frank, Eric

2010-01-01

A major impediment for regeneration of axons within the central nervous system is the presence of multiple inhibitory factors associated with myelin. Three of these factors bind to the Nogo receptor, NgR, which is expressed on axons. Administration of exogenous blockers of NgR or NgR ligands promotes the regeneration of descending axonal projections after spinal cord hemisection. A more detailed analysis of CNS regeneration can be made by examining the growth of specific classes of sensory axons into the spinal cord after dorsal root crush injury . In this study, we assessed whether administration of a soluble peptide fragment of the NgR that binds to and blocks all three NgR ligands can promote regeneration after brachial dorsal root crush in adult rats. Intraventricular infusion of sNgR for one month results in extensive regrowth of myelinated sensory axons into the white and gray matter of the dorsal spinal cord, but unmyelinated sensory afferents do not regenerate. In concert with the anatomical growth of sensory axons into the cord, there is a gradual restoration of synaptic function in the denervated region, as revealed by extracellular microelectrode recordings from the spinal gray matter in response to stimulation of peripheral nerves. These positive synaptic responses are correlated with substantial improvements in use of the forelimb, as assessed by paw preference, paw withdrawal to tactile stimuli and the ability to grasp. These results suggest that sNgR may be a potential therapy for restoring sensory function following injuries to sensory roots. PMID:19439606

[The neurotrophic effect of endogenous NT-3 from adult cat spared dorsal root ganglion on ganglionic neurons].

PubMed

Zhang, Wei; Zhou, Xue; Wang, Ting-hua; Wang, Te-wei; Liu, Su; Chen, Si-xiu; Ou, Ke-qun

2004-01-01

To investigate the neurotrophic effect of endogenous NT-3 from adult cat dorsal root ganglion (DRG) on ganglionic neurons. Rhizotomy of bilateral L1, L3, L5 and L7 dorsal roots of cats was performed, leaving L2, L4 and L6 DRG as spared DRGs. The separate neurons of normal (control) DRG, spared DRG and anti-NT-3 antibody blocking DRG were cultured in vitro respectively. The number of survival neurons and the length of neurites were measured and used for comparison in the control, spared DRG, and block groups. There were survival neurons and cell clusters in every group. The number of survival neurons and cell clusters of spared DRG group were much larger than those of the control and block groups. The neurite length of neurons, the neurite number and the length of cell clusters of spared DRG group were much greater than those of control and block groups. Endogenous NT-3 from spared DRG may act on ganglionic neurons to maintain survival of neuron and stimulate growth of neurite.

Dorsal Root Ganglion Stimulation for Complex Regional Pain Syndrome (CRPS) Recurrence after Amputation for CRPS, and Failure of Conventional Spinal Cord Stimulation.

PubMed

Goebel, Andreas; Lewis, Sarah; Phillip, Rhodri; Sharma, Manohar

2018-01-01

Limb amputation is sometimes being performed in long-standing complex regional pain syndrome (CRPS), although little evidence is available guiding management decisions, including how CRPS recurrence should be managed. This report details the management of a young soldier with CRPS recurrence 2 years after midtibial amputation for CRPS. Conventional spinal cord stimulation did not achieve paraesthetic coverage, or pain relief in the stump, whereas L4 dorsal root ganglion stimulation achieved both coverage and initially modest pain relief, and over time, substantial pain relief. Current evidence does not support the use of amputation to improve either pain or function in CRPS. Before a decision is made, in exceptional cases, about referral for amputation, dorsal root ganglion stimulation should be considered as a potentially effective treatment, even where conventional spinal cord stimulator treatment has failed to achieve reliable paraesthetic cover. Furthermore, this treatment may provide pain relief in those patients with CRPS recurrence in the stump after amputation. © 2017 World Institute of Pain.

Case of sensory ataxic ganglionopathy-myelopathy in copper deficiency.

PubMed

Zara, Gabriella; Grassivaro, Francesca; Brocadello, Filippo; Manara, Renzo; Pesenti, Francesco Francini

2009-02-15

Spinal cord involvement associated with severe copper deficiency has been reported in the last 8 years. Copper deficiency may produce an ataxic myelopathy. Clinical and neuroimaging findings are similar to the subacute combined degeneration seen in patients with vitamin B12 deficiency. Macrocytic, normocytic and microcytic anemia, leukopenia and, in severe cases, pancytopenia are well known hematologic manifestations. The most patients with copper deficiency myelopathy had unrecognized carency. Some authors suggested that early recognition and copper supplementation may prevent neurologic deterioration but clinical findings do not improve. We present a patient with copper deficiency, dorsal root ganglions and cervical dorsal columns involvement. Clinical status and neuroimaging improved after copper replacement therapy. Sensory neurons of dorsal root ganglia may be the most sensitive nervous pathway. In this case the early copper treatment allowed to improve neurologic lesions and to prevent further involvements.

New species of Schulzia (Nematoda: Molineidae) in Ptychoglossus festae (Squamata: Gymnophthalmidae) from Panama.

PubMed

Bursey, Charles R; Goldberg, Stephen R; Telford, Sam R

2006-10-01

Schulzia ptychoglossi n. sp. (Strongylida: Molineidae) from the intestines of Ptychoglossus festae (Squamata: Gymnophthalmidae) is described and illustrated. Schulzia ptychoglossi n. sp. represents the fourth species assigned to the genus and is most similar to the Venezuelan species S. usu by possessing a cervical inflation that begins a short distance from the anterior end of the body. Schulzia ptychoglossi differs from S. usu in that ray 8 separates midway between the root and tip of the dorsal ray in S. ptychoglossi, but separates close to the root of the dorsal ray in S. usu.

Modulation of Diabetes-Induced Oxidative Stress, Apoptosis, and Ca2+ Entry Through TRPM2 and TRPV1 Channels in Dorsal Root Ganglion and Hippocampus of Diabetic Rats by Melatonin and Selenium.

PubMed

Kahya, Mehmet Cemal; Nazıroğlu, Mustafa; Övey, İshak Suat

2017-04-01

Neuropathic pain and hippocampal injury can arise from the overload of diabetes-induced calcium ion (Ca 2+ ) entry and oxidative stress. The transient receptor potential (TRP) melastatin 2 (TRPM2) and TRP vanilloid type 1 (TRPV1) are expressed in sensory neurons and hippocampus. Moreover, activations of TRPM2 and TRPV1 during oxidative stress have been linked to neuronal death. Melatonin (MEL) and selenium (Se) have been considered potent antioxidants that detoxify a variety of reactive oxygen species (ROS) in neurological diseases. In order to better characterize the actions of MEL and Se in diabetes-induced peripheral pain and hippocampal injury through modulation of TRPM2 and TRPV1, we tested the effects of MEL and Se on apoptosis and oxidative stress in the hippocampal and dorsal root ganglion (DRG) neurons of streptozotocin (STZ)-induced diabetic rats. Fifty-eight rats were divided into six groups. The first group was used as control. The second group was used as the diabetic group. The third and fourth groups received Se and MEL, respectively. Intraperitoneal Se and MEL were given to diabetic rats in the fifth and sixth groups. On the 14th day, hippocampal and DRG neuron samples were freshly taken from all animals. The neurons were stimulated with a TRPV1 channel agonist (capsaicin) and a TRPM2 channel agonist (cumene hydroperoxide). We observed a modulator role of MEL and Se on intracellular free Ca 2+ concentrations, current densities of TRPM2 and TRPV1 channels, apoptosis, caspase 3, caspase 9, mitochondrial depolarization, reduced glutathione, glutathione peroxidase, lipid peroxidation, and intracellular ROS production values in the neurons. In addition, procaspase 3 and 9 activities in western blot analyses of the brain cortex were also decreased by MEL and Se treatments. In conclusion, in our diabetes experimental model, TRPM2 and TRPV1 channels are involved in the Ca 2+ entry-induced neuronal death and modulation of this channel activity by MEL and Se treatment may account for their neuroprotective activity against apoptosis and Ca 2+ entry. Graphical Abstract Possible molecular pathways of involvement of melatonin and selenium in diabetes-induced apoptosis, oxidative stress, and calcium accumulation through TRPM2 and TRPV1 channels in the hippocampus and DRG neurons of rats. The TRPM2 channel is activated by ADP-ribose and oxidative stress although it is inhibited by ACA. The TRPV1 channel is activated by oxidative stress and capsaicin and it is blocked by capsazepine (CPZ). Diabetes can result in augmented ROS release in hippocampal and DRG neurons through polyol reactions, leading to Ca 2+ uptake through TRPM2 and TRPV1 channels. Mitochondria were reported to accumulate Ca 2+ provided intracellular Ca 2+ rises, thereby leading to the depolarization of mitochondrial membranes and release of apoptosis-inducing factors such as caspase 3 and caspase 9. Melatonin and selenium reduce TRPM2 and TRPV1 channel activation through the modulation of polyol oxidative reactions and selenium-dependent glutathione peroxidase (GSH-Px) antioxidant pathways.

Actions of (-)-baclofen on rat dorsal horn neurons.

PubMed

Kangrga, I; Jiang, M C; Randić, M

1991-10-25

The actions of a gamma-aminobutyric acid B (GABAB) agonist, (-)-baclofen, on the electrophysiological properties of neurons and synaptic transmission in the spinal dorsal horn (laminae I-IV) were examined by using intracellular recordings in spinal cord slice from young rats. In addition, the effects of baclofen on the dorsal root stimulation-evoked outflow of glutamate and aspartate from the spinal dorsal horn were examined by using high performance liquid chromatography (HPLC) with flourimetric detection. Superfusion of baclofen (5 nM to 10 microM) hyperpolarized, in a stereoselective and bicuculline-insensitive manner, the majority (86%) of tested neurons. The hyperpolarization was associated with a decrease in membrane resistance and persisted in a nominally zero-Ca2+, 10 mM Mg(2+)- or a TTX-containing solution. Our findings indicate that the hyperpolarizing effect of baclofen is probably due to an increase in conductance to potassium ions. Baclofen decreased the direct excitability of dorsal horn neurons, enhanced accommodation of spike discharge, and reduced the duration of Ca(2+)-dependent action potentials. Baclofen depressed, or blocked, excitatory postsynaptic potentials evoked by electrical stimulation of the dorsal roots. Spontaneously occurring synaptic potentials were also reversibly depressed by baclofen. Whereas baclofen did not produce any consistent change in the rate of the basal outflow of glutamate and aspartate, the stimulation-evoked release of the amino acids was blocked. The present results suggest that baclofen, by activating GABAB receptors, may modulate spinal afferent processing in the superficial dorsal horn by at least two mechanisms: (1) baclofen depresses excitatory synaptic transmission primarily by a presynaptic mechanism involving a decrease in the release of excitatory amino acids, and (2) at higher concentrations, the hyperpolarization and increased membrane conductance may contribute to the depressant effect of baclofen on excitatory synaptic transmission in the rat spinal dorsal horn.

Linear signaling in the Toll-Dorsal pathway of Drosophila: activated Pelle kinase specifies all threshold outputs of gene expression while the bHLH protein Twist specifies a subset.

PubMed

Stathopoulos, Angelike; Levine, Michael

2002-07-01

Differential activation of the Toll receptor leads to the formation of a broad Dorsal nuclear gradient that specifies at least three patterning thresholds of gene activity along the dorsoventral axis of precellular embryos. We investigate the activities of the Pelle kinase and Twist basic helix-loop-helix (bHLH) transcription factor in transducing Toll signaling. Pelle functions downstream of Toll to release Dorsal from the Cactus inhibitor. Twist is an immediate-early gene that is activated upon entry of Dorsal into nuclei. Transgenes misexpressing Pelle and Twist were introduced into different mutant backgrounds and the patterning activities were visualized using various target genes that respond to different thresholds of Toll-Dorsal signaling. These studies suggest that an anteroposterior gradient of Pelle kinase activity is sufficient to generate all known Toll-Dorsal patterning thresholds and that Twist can function as a gradient morphogen to establish at least two distinct dorsoventral patterning thresholds. We discuss how the Dorsal gradient system can be modified during metazoan evolution and conclude that Dorsal-Twist interactions are distinct from the interplay between Bicoid and Hunchback, which pattern the anteroposterior axis.

The RNA binding and transport proteins staufen and fragile X mental retardation protein are expressed by rat primary afferent neurons and localize to peripheral and central axons.

PubMed

Price, T J; Flores, C M; Cervero, F; Hargreaves, K M

2006-09-15

Neuronal proteins have been traditionally viewed as being derived solely from the soma; however, accumulating evidence indicates that dendritic and axonal sites are capable of a more autonomous role in terms of new protein synthesis. Such extra-somal translation allows for more rapid, on-demand regulation of neuronal structure and function than would otherwise be possible. While mechanisms of dendritic RNA transport have been elucidated, it remains unclear how RNA is trafficked into the axon for this purpose. Primary afferent neurons of the dorsal root (DRG) and trigeminal (TG) ganglia have among the longest axons in the neuraxis and such axonal protein synthesis would be advantageous, given the greater time involved for protein trafficking to occur via axonal transport. Therefore, we hypothesized that these primary sensory neurons might express proteins involved in RNA transport. Rat DRG and TG neurons expressed staufen (stau) 1 and 2 (detected at the mRNA level) and stau2 and fragile x mental retardation protein (FMRP; detected at the protein level). Stau2 mRNA was also detected in human TG neurons. Stau2 and FMRP protein were localized to the sciatic nerve and dorsal roots by immunohistochemistry and to dorsal roots by Western blot. Stau2 and FMRP immunoreactivities colocalized with transient receptor potential channel type 1 immunoreactivity in sensory axons of the sciatic nerve and dorsal root, suggesting that these proteins are being transported into the peripheral and central terminals of nociceptive sensory axons. Based on these findings, we propose that stau2 and FMRP proteins are attractive candidates to subserve RNA transport in sensory neurons, linking somal transcriptional events to axonal translation.

THE RNA BINDING AND TRANSPORT PROTEINS STAUFEN AND FRAGILE X MENTAL RETARDATION PROTEIN ARE EXPRESSED BY RAT PRIMARY AFFERENT NEURONS AND LOCALIZE TO PERIPHERAL AND CENTRAL AXONS

PubMed Central

PRICE, T. J.; FLORES, C. M.; CERVERO, F.; HARGREAVES, K. M.

2007-01-01

Neuronal proteins have been traditionally viewed as being derived solely from the soma; however, accumulating evidence indicates that dendritic and axonal sites are capable of a more autonomous role in terms of new protein synthesis. Such extra-somal translation allows for more rapid, on-demand regulation of neuronal structure and function than would otherwise be possible. While mechanisms of dendritic RNA transport have been elucidated, it remains unclear how RNA is trafficked into the axon for this purpose. Primary afferent neurons of the dorsal root (DRG) and trigeminal (TG) ganglia have among the longest axons in the neuraxis and such axonal protein synthesis would be advantageous, given the greater time involved for protein trafficking to occur via axonal transport. Therefore, we hypothesized that these primary sensory neurons might express proteins involved in RNA transport. Rat DRG and TG neurons expressed staufen (stau) 1 and 2 (detected at the mRNA level) and stau2 and fragile × mental retardation protein (FMRP; detected at the protein level). Stau2 mRNA was also detected in human TG neurons. Stau2 and FMRP protein were localized to the sciatic nerve and dorsal roots by immunohistochemistry and to dorsal roots by Western blot. Stau2 and FMRP immunoreactivities colocalized with transient receptor potential channel type 1 immunoreactivity in sensory axons of the sciatic nerve and dorsal root, suggesting that these proteins are being transported into the peripheral and central terminals of nociceptive sensory axons. Based on these findings, we propose that stau2 and FMRP proteins are attractive candidates to subserve RNA transport in sensory neurons, linking somal transcriptional events to axonal translation. PMID:16809002

Polysensory response characteristics of dorsal root ganglion neurones that may serve sensory functions during myocardial ischaemia.

PubMed

Huang, M H; Horackova, M; Negoescu, R M; Wolf, S; Armour, J A

1996-09-01

To determine the response characteristics of dorsal root ganglion neurones that may serve sensory functions during myocardial ischaemia. Extracellular recordings were made from 54 spontaneously active and 5 normally quiescent dorsal root ganglion neurones (T2-T5) in 22 anaesthetized open-chest dogs under control conditions and during epicardial mechanical or chemical stimulation and myocardial ischaemia. The activity of 78% of spontaneously active and all quiescent neurones with left ventricular sensory fields was modified by left ventricular ischaemia. Forty-six spontaneously active neurones (85%) were polysensory with respect to mechanical and chemical stimuli. The 5 quiescent neurones responded only to chemical stimuli. Spontaneously active neurones associated with left ventricular mechanosensory endings (37 neurones) generated four different activity patterns in response to similar mechanical stimuli (high or low pressure active, high-low pressure active, high-low pressure inactive). A fifth group generated activity which was not related to chamber dynamics. Adenosine, adenosine 5'-triphosphate, substance P and bradykinin modified 72, 61, 65 and 63% of the spontaneously active neurones, respectively. Maximum local mechanical or chemical stimuli enhanced activity to similar degrees, as did ischaemia. Each ischaemia-sensitive neurone displayed unique activity patterns in response to similar mechanical or chemical stimuli. Most myocardial ischemia-sensitive dorsal root ganglion neurones associated with epicardial neurites sense mechanical and multiple chemical stimuli, a small population sensing only mechanical or chemical stimuli. Activity patterns generated by these neurones depend on their primary sensory characteristics or those of other neurones that may converge on them, as well as the type and magnitude of the stimuli that impinge upon their sensory fields, both normally and during ischaemia.

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 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.

Lumbar dorsal ramus syndrome.

PubMed

Bogduk, N

1980-11-15

Low back pain, referred pain in the lower limbs, and spasm of the back, gluteal, and hamstring muscles are clinical features which can be induced in normal volunteers by stimulating structures which are innervated by the lumbar dorsal rami. Conversely, they can be relieved in certain patients by selective interruption of conduction along dorsal rami. These facts permit the definition of a lumbar dorsal ramus syndrome, which can be distinguished from the intervertebral disc syndrome and other forms of low back pain. The distinguishing feature is that, in lumbar dorsal ramus syndrome, all the clinical features are exclusively mediated by dorsal rami and do not arise from nerve-root compression. The pathophysiology, pathology, and treatment of this syndrome are described. Recognition of this syndrome, and its treatment with relatively minor procedures, can obviate the need for major surgery which might otherwise be undertaken.

Interactions between Dorsal and Ventral Root Stimulation on the Generation of Locomotor-Like Activity in the Neonatal Mouse Spinal Cord

PubMed Central

2016-01-01

Abstract We investigated whether dorsal (DR) and ventral root (VR) stimulus trains engage common postsynaptic components to activate the central pattern generator (CPG) for locomotion in the neonatal mouse spinal cord. VR stimulation did not activate the first order interneurons mediating the activation of the locomotor CPG by sacrocaudal afferent stimulation. Simultaneous stimulation of adjacent dorsal or ventral root pairs, subthreshold for evoking locomotor-like activity, did not summate to activate the CPG. This suggests that locomotor-like activity is triggered when a critical class of efferent or afferent axons is stimulated and does not depend on the number of stimulated axons or activated postsynaptic neurons. DR- and VR-evoked episodes exhibited differences in the coupling between VR pairs. In DR-evoked episodes, the coupling between the ipsilateral and contralateral flexor/extensor roots was similar and stronger than the bilateral extensor roots. In VR-evoked episodes, ipsilateral flexor/extensor coupling was stronger than both the contralateral flexor/extensor and the bilateral extensor coupling. For both types of stimulation, the coupling was greatest between the bilateral L1/L2 flexor-dominated roots. This indicates that the recruitment and/or the firing pattern of motoneurons differed in DR and VR-evoked episodes. However, the DR and VR trains do not appear to activate distinct CPGs because trains of DR and VR stimuli at frequencies too low to evoke locomotor-like activity did so when they were interleaved. These results indicate that the excitatory actions of VR stimulation converge onto the CPG through an unknown pathway that is not captured by current models of the locomotor CPG. PMID:27419215

The nerve supply of the lumbar intervertebral disc.

PubMed

Edgar, M A

2007-09-01

The anatomical studies, basic to our understanding of lumbar spine innervation through the sinu-vertebral nerves, are reviewed. Research in the 1980s suggested that pain sensation was conducted in part via the sympathetic system. These sensory pathways have now been clarified using sophisticated experimental and histochemical techniques confirming a dual pattern. One route enters the adjacent dorsal root segmentally, whereas the other supply is non-segmental ascending through the paravertebral sympathetic chain with re-entry through the thoracolumbar white rami communicantes. Sensory nerve endings in the degenerative lumbar disc penetrate deep into the disrupted nucleus pulposus, insensitive in the normal lumbar spine. Complex as well as free nerve endings would appear to contribute to pain transmission. The nature and mechanism of discogenic pain is still speculative but there is growing evidence to support a 'visceral pain' hypothesis, unique in the muscloskeletal system. This mechanism is open to 'peripheral sensitisation' and possibly 'central sensitisation' as a potential cause of chronic back pain.

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.

Chronic methylmercurialism in a horse

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

Seawright, A.A.; Roberts, M.C.; Costigan, P.

1978-02-01

Chronic methylmercurialism was produced in a horse given 10 g methylmercury chloride over 10 weeks. Neurological signs, particularly proprioceptive disturbances, were apparent by the final week of dosing and became more severe thereafter. An exudative dermatitis, a reluctance to move, weight loss, reduced appetite and dullness were among the earlier clinical signs, and renal changes characterized by a steadily increasing BUN and glucosuria were detected later. Pathological lesions were confined to the kidneys and the nervous system. There was mild neuronal degeneration in the cerebral cortex and in the cerebellar cortex, axonal demyelination in the dorsal columns of the spinalmore » cord and extensive degeneration of ganglion cells in the dorsal root ganglia. The blood organic mercury level, which had plateaued in the second month, increased rapidly in the last weeks of dosing with a sharp rise terminally. This pattern was repeated for the much lower inorganic mercury levels except for a terminal decrease. The proportion of inorganic mercury was five times greater in the dorsal root ganglia than elsewhere in the CNS, although total mercury levels were similar. Highest tissue mercury levels were found in the liver and kidneys, over 50% being in the form of inorganic mercury. As dealkylation of the methylmercury appeared to be more efficient in the dorsal root ganglia and the kidneys, inorganic mercury derived therefrom may have been responsible for some of the clinical and pathological features of this intoxication in the horse. 21 references, 6 figures, 2 tables.« less

Cytoarchitecture and Cortical Connections of the Anterior Insula and Adjacent Frontal Motor Fields in the Rhesus Monkey

PubMed Central

Morecraft, RJ; Stilwell-Morecraft, KS; Ge, J; Cipolloni, PB; Pandya, DN

2015-01-01

The cytoarchitecture and cortical connections of the ventral motor region are investigated using Nissl, and NeuN staining methods and the fluorescent retrograde tract tracing technique in the rhesus monkey. On the basis of gradual laminar differentiation, it is shown that the ventral motor region stems from the ventral proisocortical area (anterior insula and dorsal Sylvian opercular region). The cytoarchitecture of the ventral motor region is shown to progress in three lines, as we have recently shown for the dorsal motor region. Namely, root (anterior insular and dorsal Sylvian opercular area ProM), belt (ventral premotor cortex) and core (precentral motor cortex) lines. This stepwise architectonic organization is supported by the overall patterns of corticocortical connections. Areas in each line are sequentially interconnected (intralineal connections) and all lines are interconnected (interlinear connections). Moreover, root areas, as well as some of the belt areas of the ventral and dorsal trend are interconnected. The ventral motor region is also connected with the ventral somatosensory areas in a topographic manner. The root and belt areas of ventral motor region are connected with paralimbic, multimodal and prefrontal (outer belt) areas. In contrast, the core area has a comparatively more restricted pattern of corticocortical connections. This architectonic and connectional organization is consistent in part, with the functional organization of the ventral motor region as reported in behavioral and neuroimaging studies which include the mediation of facial expression and emotion, communication, phonic articulation, and language in human. PMID:26496798

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

PubMed Central

Zerboni, Leigh; Arvin, Ann

2015-01-01

Varicella zoster virus (VZV), a human alphaherpesvirus, causes varicella during primary infection. VZV reactivation from neuronal latency may cause herpes zoster, post herpetic neuralgia (PHN) and other neurologic syndromes. To investigate VZV neuropathogenesis, we developed a model using human dorsal root ganglia (DRG) xenografts in immunodeficient (SCID) mice. The SCID DRG model provides an opportunity to examine characteristics of VZV infection that occur in the context of the specialized architecture of DRG, in which nerve cell bodies are ensheathed by satellite glial cells (SGC) which support neuronal homeostasis. We hypothesized that VZV exhibits neuron-subtype specific tropism and that VZV tropism for SGC contributes to VZV-related ganglionopathy. Based on quantitative analyses of viral and cell protein expression in DRG tissue sections, we demonstrated that, whereas DRG neurons had an immature neuronal phenotype prior to implantation, subtype heterogeneity was observed within 20 weeks and SGC retained the capacity to maintain neuronal homeostasis longterm. Profiling VZV protein expression in DRG neurons showed that VZV enters peripherin+ nociceptive and RT97+ mechanoreceptive neurons by both axonal transport and contiguous spread from SGC, but replication in RT97+ neurons is blocked. Restriction occurs even when the SGC surrounding the neuronal cell body were infected and after entry and ORF61 expression, but before IE62 or IE63 protein expression. Notably, although contiguous VZV spread with loss of SGC support would be predicted to affect survival of both nociceptive and mechanoreceptive neurons, RT97+ neurons showed selective loss relative to peripherin+ neurons at later times in DRG infection. Profiling cell factors that were upregulated in VZV-infected DRG indicated that VZV infection induced marked pro-inflammatory responses, as well as proteins of the interferon pathway and neuroprotective responses. These neuropathologic changes observed in sensory ganglia infected with VZV may help to explain the neurologic sequelae often associated with zoster and PHN. PMID:26090802

Blocking herpes simplex virus 2 glycoprotein E immune evasion as an approach to enhance efficacy of a trivalent subunit antigen vaccine for genital herpes.

PubMed

Awasthi, Sita; Huang, Jialing; Shaw, Carolyn; Friedman, Harvey M

2014-08-01

Herpes simplex virus 2 (HSV-2) subunit antigen vaccines targeting virus entry molecules have failed to prevent genital herpes in human trials. Our approach is to include a virus entry molecule and add antigens that block HSV-2 immune evasion. HSV-2 glycoprotein C (gC2) is an immune evasion molecule that inhibits complement. We previously reported that adding gC2 to gD2 improved vaccine efficacy compared to the efficacy of either antigen alone in mice and guinea pigs. Here we demonstrate that HSV-2 glycoprotein E (gE2) functions as an immune evasion molecule by binding the IgG Fc domain. HSV-2 gE2 is synergistic with gC2 in protecting the virus from antibody and complement neutralization. Antibodies produced by immunization with gE2 blocked gE2-mediated IgG Fc binding and cell-to-cell spread. Mice immunized with gE2 were only partially protected against HSV-2 vaginal challenge in mice; however, when gE2 was added to gC2/gD2 to form a trivalent vaccine, neutralizing antibody titers with and without complement were significantly higher than those produced by gD2 alone. Importantly, the trivalent vaccine protected the dorsal root ganglia (DRG) of 32/33 (97%) mice between days 2 and 7 postchallenge, compared with 27/33 (82%) in the gD2 group. The HSV-2 DNA copy number was significantly lower in mice immunized with the trivalent vaccine than in those immunized with gD2 alone. The extent of DRG protection using the trivalent vaccine was better than what we previously reported for gC2/gD2 immunization. Therefore, gE2 is a candidate antigen for inclusion in a multivalent subunit vaccine that attempts to block HSV-2 immune evasion. Herpes simplex virus is the most common cause of genital ulcer disease worldwide. Infection results in emotional distress for infected individuals and their partners, is life threatening for infants exposed to herpes during childbirth, and greatly increases the risk of individuals acquiring and transmitting HIV infection. A vaccine that prevents genital herpes infection will have major public health benefits. Our vaccine approach includes strategies to prevent the virus from evading immune attack. Mice were immunized with a trivalent vaccine containing an antigen that induces antibodies to block virus entry and two antigens that induce antibodies that block immune evasion from antibody and complement. Immunized mice demonstrated no genital disease, and 32/33 (97%) animals had no evidence of infection of dorsal root ganglia, suggesting that the vaccine may prevent the establishment of latency and recurrent infections. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Origins, actions and dynamic expression patterns of the neuropeptide VGF in rat peripheral and central sensory neurones following peripheral nerve injury

PubMed Central

Moss, Andrew; Ingram, Rachel; Koch, Stephanie; Theodorou, Andria; Low, Lucie; Baccei, Mark; Hathway, Gareth J; Costigan, Michael; Salton, Stephen R; Fitzgerald, Maria

2008-01-01

Background The role of the neurotrophin regulated polypeptide, VGF, has been investigated in a rat spared injury model of neuropathic pain. This peptide has been shown to be associated with synaptic strengthening and learning in the hippocampus and while it is known that VGFmRNA is upregulated in dorsal root ganglia following peripheral nerve injury, the role of this VGF peptide in neuropathic pain has yet to be investigated. Results Prolonged upregulation of VGF mRNA and protein was observed in injured dorsal root ganglion neurons, central terminals and their target dorsal horn neurons. Intrathecal application of TLQP-62, the C-terminal active portion of VGF (5–50 nmol) to naïve rats caused a long-lasting mechanical and cold behavioral allodynia. Direct actions of 50 nM TLQP-62 upon dorsal horn neuron excitability was demonstrated in whole cell patch recordings in spinal cord slices and in receptive field analysis in intact, anesthetized rats where significant actions of VGF were upon spontaneous activity and cold evoked responses. Conclusion VGF expression is therefore highly modulated in nociceptive pathways following peripheral nerve injury and can cause dorsal horn cell excitation and behavioral hypersensitivity in naïve animals. Together the results point to a novel and powerful role for VGF in neuropathic pain. PMID:19077191

Effect of monensin on the levels of tachykinins and their processing enzyme activity in rat dorsal root ganglia.

PubMed

Chikuma, Toshiyuki; Inomata, Yuji; Tsuchida, Ken; Hojo, Hiroshi; Kato, Takeshi

2002-06-28

Th effect of monensin, which inhibits trans-Golgi function, on the levels of tachykinins and their processing enzyme activity was examined in organ-cultured rat dorsal root ganglia (DRG). Using an enzyme immunoassay method, we measured neurokinin A and substance P immunoreactivity in the DRG cultured for 72 h with and without 0.1 microM monensin. Both tachykinins were reduced in the DRG treated with monensin. Treatment with monensin also reduced the activity of carboxypeptidase E, which is one of the proteolytic processing enzymes of neuropeptides. These data suggest that proteolytic processing enzymes may in part modulate the biological activity of neuropeptides within a trans-Golgi apparatus.

The role of dorsal root ganglia activation and brain-derived neurotrophic factor in multiple sclerosis

PubMed Central

Zhu, Wenjun; Frost, Emma E; Begum, Farhana; Vora, Parvez; Au, Kelvin; Gong, Yuewen; MacNeil, Brian; Pillai, Prakash; Namaka, Mike

2012-01-01

Abstract Multiple sclerosis (MS) is characterized by focal destruction of the white matter of the brain and spinal cord. The exact mechanisms underlying the pathophysiology of the disease are unknown. Many studies have shown that MS is predominantly an autoimmune disease with an inflammatory phase followed by a demyelinating phase. Recent studies alongside current treatment strategies, including glatiramer acetate, have revealed a potential role for brain-derived neurotrophic factor (BDNF) in MS. However, the exact role of BDNF is not fully understood. We used the experimental autoimmune encephalomyelitis (EAE) model of MS in adolescent female Lewis rats to identify the role of BDNF in disease progression. Dorsal root ganglia (DRG) and spinal cords were harvested for protein and gene expression analysis every 3 days post-disease induction (pdi) up to 15 days. We show significant increases in BDNF protein and gene expression in the DRG of EAE animals at 12 dpi, which correlates with peak neurological disability. BDNF protein expression in the spinal cord was significantly increased at 12 dpi, and maintained at 15 dpi. However, there was no significant change in mRNA levels. We show evidence for the anterograde transport of BDNF protein from the DRG to the dorsal horn of the spinal cord via the dorsal roots. Increased levels of BDNF within the DRG and spinal cord in EAE may facilitate myelin repair and neuroprotection in the CNS. The anterograde transport of DRG-derived BDNF to the spinal cord may have potential implications in facilitating central myelin repair and neuroprotection. PMID:22050733

Evaluation of lumbar transforaminal epidural injections with needle placement and contrast flow patterns: a prospective, descriptive report.

PubMed

Manchikanti, Laxmaiah; Cash, Kim A; Pampati, Vidyasagar; Damron, Kim S; McManus, Carla D

2004-04-01

Transforaminal epidural steroid injection is one of the commonly employed modalities of treatment in managing nerve root pain. However, there have been no controlled prospective evaluations of epidural and nerve root contrast distribution patterns and other aspects of fluoroscopically directed lumbosacral transforaminal epidural steroid injections. To evaluate contrast flow patterns and intravascular needle placement of fluoroscopically guided lumbosacral transforaminal epidural injections. A prospective, observational study. A total of 100 consecutive patients undergoing fluoroscopically guided transforaminal epidural steroid injections were evaluated. The contrast flow patterns, ventral or dorsal epidural filling, nerve root filling, C-arm time, and intravascular needle placement were evaluated. Ventral epidural filling was seen in 88% of the procedures, in contrast to dorsal filling noted in 9% of the procedures. Nerve root filling was seen in 97% of the procedures. Total intravenous placement of the needle was noted in 22% of the procedures, whereas negative flashback and aspiration was noted in 5% of the procedures. Lumbosacral transforaminal epidural injections, performed under fluoroscopic visualization, provide excellent nerve root filling and ventral epidural filling patterns. However, unrecognized intravascular needle placement with negative flashback or aspiration was noted in 5% of the procedures.

The role of capsaicin-sensitive muscle afferents in fatigue-induced modulation of the monosynaptic reflex in the rat.

PubMed

Pettorossi, V E; Della Torre, G; Bortolami, R; Brunetti, O

1999-03-01

1. The role of group III and IV afferent fibres of the lateral gastrocnemious muscle (LG) in modulating the homonymous monosynaptic reflex was investigated during muscle fatigue in spinalized rats. 2. Muscle fatigue was induced by a series of increasing tetanic electrical stimuli (85 Hz, 600 ms) delivered to the LG muscle nerve. Series consisted of increasing train numbers from 1 to 60. 3. Potentials from the spinal cord LG motor pool and from the ventral root were recorded in response to proprioceptive afferent stimulation and analysed before and during tetanic muscle activations. Both the pre- and postsynaptic waves showed an initial enhancement and, after a '12-train' series, an increasing inhibition. 4. The enhancement of the responses to muscle fatiguing stimulation disappeared after L3-L6 dorsal root section, while a partial reflex inhibition was still present. Conversely, after section of the corresponding ventral root, there was only a reduction in the inhibitory effect. 5. The monosynaptic reflex was also studied in animals in which a large number of group III and IV muscle afferents were eliminated by injecting capsaicin (10 mM) into the LG muscle. As a result of capsaicin treatment, the fatigue-induced inhibition of the pre- and postsynaptic waves disappeared, while the response enhancement remained. 6. We concluded that the monosynaptic reflex inhibition, but not the enhancement, was mediated by those group III and IV muscle afferents that are sensitive to the toxic action of capsaicin. The afferents that are responsible for the response enhancement enter the spinal cord through the dorsal root, while those responsible for the inhibition enter the spinal cord through both the ventral and dorsal roots.

The role of capsaicin-sensitive muscle afferents in fatigue-induced modulation of the monosynaptic reflex in the rat

PubMed Central

Pettorossi, V E; Torre, G Della; Bortolami, R; Brunetti, O

1999-01-01

The role of group III and IV afferent fibres of the lateral gastrocnemious muscle (LG) in modulating the homonymous monosynaptic reflex was investigated during muscle fatigue in spinalized rats. Muscle fatigue was induced by a series of increasing tetanic electrical stimuli (85 Hz, 600 ms) delivered to the LG muscle nerve. Series consisted of increasing train numbers from 1 to 60. Potentials from the spinal cord LG motor pool and from the ventral root were recorded in response to proprioceptive afferent stimulation and analysed before and during tetanic muscle activations. Both the pre- and postsynaptic waves showed an initial enhancement and, after a ‘12-train’ series, an increasing inhibition. The enhancement of the responses to muscle fatiguing stimulation disappeared after L3-L6 dorsal root section, while a partial reflex inhibition was still present. Conversely, after section of the corresponding ventral root, there was only a reduction in the inhibitory effect. The monosynaptic reflex was also studied in animals in which a large number of group III and IV muscle afferents were eliminated by injecting capsaicin (10 mM) into the LG muscle. As a result of capsaicin treatment, the fatigue-induced inhibition of the pre- and postsynaptic waves disappeared, while the response enhancement remained. We concluded that the monosynaptic reflex inhibition, but not the enhancement, was mediated by those group III and IV muscle afferents that are sensitive to the toxic action of capsaicin. The afferents that are responsible for the response enhancement enter the spinal cord through the dorsal root, while those responsible for the inhibition enter the spinal cord through both the ventral and dorsal roots. PMID:10050025

Twinning of amphibian embryos by centrifugation

NASA Technical Reports Server (NTRS)

Black, S. D.

1984-01-01

In the frog Xenopus laevis, the dorsal structures of the embryonic body axis normally derive from the side of the egg opposite the side of sperm entry. However, if the uncleaved egg is inclined at lg or centrifuged in an inclined position, this topographic relationship is overridden: the egg makes its dorsal axial structures according to its orientation in the gravitational/centrifugal field, irrespective of the position of sperm entry. Certain conditions of centrifugation cause eggs to develop into conjoined twins with two sets of axial structures. A detailed analysis of twinning provided some insight into experimental axis orientation. First, as with single-axis embryos, both axes in twins are oriented according to the direction of centrifugation. One axis forms at the centripetal side of the egg and the other forms at the centrifugal side, even when the side of sperm entry is normal to the centrifugal force vector. Second, if eggs are centrifuged to give twins, but are inclined at lg to prevent post-centrifugation endoplasmic redistributions, only single-axis embryos develop. Thus, a second redistribution is required for high-frequency secondary axis formation. This can be accomplished by lg (as in the single centrifugations) or by a second centrifugation directed along the egg's animal-vegetal axis.

Switch from intracellular to intercellular invasion during water stress-tolerant legume nodulation

PubMed Central

Goormachtig, Sofie; Capoen, Ward; James, Euan K.; Holsters, Marcelle

2004-01-01

Rhizobia colonize their legume hosts by different modes of entry while initiating symbiotic nitrogen fixation. Most legumes are invaded via growing root hairs by the root hair-curl mechanism, which involves epidermal cell responses. However, invasion of a number of tropical legumes happens through fissures at lateral root bases by cortical, intercellular crack entry. In the semiaquatic Sesbania rostrata, the bacteria entered via root hair curls under nonflooding conditions. Upon flooding, root hair growth was prevented, invasion on accessible root hairs was inhibited, and intercellular invasion was recruited. The plant hormone ethylene was involved in these processes. The occurrence of both invasion pathways on the same host plant enabled a comparison to be made of the structural requirements for the perception of nodulation factors, which were more stringent for the epidermal root hair invasion than for the cortical intercellular invasion at lateral root bases. PMID:15079070

[Effect of bee venom injection on TrkA and TRPV1 expression in the dorsal root ganglion of rats with collagen-induced arthritis].

PubMed

Xian, Pei-Feng; Chen, Ying; Yang, Lu; Liu, Guo-Tao; Peng, Peng; Wang, Sheng-Xu

2016-06-01

To investigate the therapeutic effect of acupoint injection of bee venom on collagen-induced arthritis (CIA) in rats and explore the mechanism of bee venom therapy in the treatment of rheumatoid arthritis. Fifteen male Wistar rats were randomly divided into bee venom treatment group (BV group), CIA model group, and control group. In the former two groups, CIA was induced by injections of collagen II+IFA (0.2 mL) via the tail vein, and in the control group, normal saline was injected instead. The rats in BV group received daily injection of 0.1 mL (3 mg/mL) bee venom for 7 consecutive days. All the rats were assessed for paw thickness and arthritis index from days 14 to 21, and the pain threshold was determined on day 21. The expressions of TRPV1 and TrkA in the dorsal root ganglion at the level of L4-6 were detected using immunohistochemistry and Western blotting, respectively. The rats in CIA model group started to show paw swelling on day 10, and by day 14, all the rats in this group showed typical signs of CIA. In BV group, the rats receiving been venom therapy for 7 days showed a significantly smaller paw thickness and a low arthritis index than those in the model group. The pain threshold was the highest in the control group and the lowest in the model group. TRPV1-positive cells and TrkA expression in the dorsal root ganglion was significantly reduced in BV group as compared with that in the model group. s Injection of bee venom can decrease expression of TRPV1 and TrkA in the dorsal root ganglion to produce anti-inflammatory and analgesic effects, suggesting the potential value of bee venom in the treatment of rheumatoid arthritis.

Adrenergic receptors inhibit TRPV1 activity in the dorsal root ganglion neurons of rats.

PubMed

Matsushita, Yumi; Manabe, Miki; Kitamura, Naoki; Shibuya, Izumi

2018-01-01

Transient receptor potential vanilloid type 1 (TRPV1) is a polymodal receptor channel that responds to multiple types of stimuli, such as heat, acid, mechanical pressure and some vanilloids. Capsaicin is the most commonly used vanilloid to stimulate TRPV1. TRPV1 channels are expressed in dorsal root ganglion neurons that extend to Aδ- and C-fibers and have a role in the transduction of noxious inputs to the skin into the electrical signals of the sensory nerve. Although noradrenergic nervous systems, including the descending antinociceptive system and the sympathetic nervous system, are known to modulate pain sensation, the functional association between TRPV1 and noradrenaline in primary sensory neurons has rarely been examined. In the present study, we examined the effects of noradrenaline on capsaicin-evoked currents in cultured dorsal root ganglion neurons of the rat by the whole-cell voltage clamp method. Noradrenaline at concentrations higher than 0.1 pM significantly reduced the amplitudes of the inward capsaicin currents recorded at -60 mV holding potential. This inhibitory action was reversed by either yohimbine (an α2 antagonist, 10 nM) or propranolol (a β antagonist, 10 nM). The α2 agonists, clonidine (1 pM) and dexmedetomidine (1 pM) inhibited capsaicin currents, and yohimbine (1 nM) reversed the effects of clonidine. The inhibitory action of noradrenaline was not seen in the neurons pretreated with pertussis toxin (100 μg/ml for 24 h) and the neurons dialyzed intracellularly with guanosine 5'- [β-thio] diphosphate (GDPβS, 200 μM), the catalytic subunit of protein kinase A (250 U/ml) or okadaic acid (1 μM). These results suggest that noradrenaline directly acts on dorsal root ganglion neurons to inhibit the activity of TRPV1 depending on the activation of α2-adrenoceptors followed by the inhibition of the adenylate cyclase/cAMP/protein kinase A pathway.

Foot orgasm syndrome: a case report in a woman.

PubMed

Waldinger, Marcel D; de Lint, Govert J; van Gils, Ad P G; Masir, Farhad; Lakke, Egbert; van Coevorden, Ruben S; Schweitzer, Dave H

2013-08-01

Spontaneous orgasm triggered from inside the foot has so far not been reported in medical literature. The study aims to report orgasmic feelings in the left foot of a woman. A woman presented with complaints of undesired orgasmic sensations originating in her left foot. In-depth interview, physical examination, sensory testing, magnetic resonance imaging (MRI-scan), electromyography (EMG), transcutaneous electrical nerve stimulation (TENS), and blockade of the left S1 dorsal root ganglion were performed. The main outcomes are description of this clinical syndrome, results of TENS application, and S1 dorsal root ganglion blockade. Subtle attenuation of sensory amplitudes of the left suralis, and the left medial and lateral plantar nerve tracts was found at EMG. MRI-scan disclosed no foot abnormalities. TENS at the left metatarso-phalangeal joint-III of the left foot elicited an instant orgasmic sensation that radiated from plantar toward the vagina. TENS applied to the left side of the vagina elicited an orgasm that radiated to the left foot. Diagnostic blockade of the left S1 dorsal root ganglion with 0.8 mL bupivacaine 0.25 mg attenuated the frequency and intensity of orgasmic sensation in the left foot with 50% and 80%, respectively. Additional therapeutic blockade of the same ganglion with 0.8 mL bupivacaine 0.50 mg combined with pulsed radiofrequency treatment resulted in a complete disappearance of the foot-induced orgasmic sensations. Foot orgasm syndrome (FOS) is descibed in a woman. Blockade of the left S1 dorsal root ganglion alleviated FOS. It is hypothesized that FOS, occurring 1.5 years after an intensive care emergency, was caused by partial nerve regeneration (axonotmesis), after which afferent (C-fiber) information from a small reinnervated skin area of the left foot and afferent somatic and autonomous (visceral) information from the vagina on at least S1 spinal level is misinterpreted by the brain as being solely information originating from the vagina. © 2013 International Society for Sexual Medicine.

Lectin Ulex europaeus agglutinin I specifically labels a subset of primary afferent fibers which project selectively to the superficial dorsal horn of the spinal cord.

PubMed

Mori, K

1986-02-19

To examine differential carbohydrate expression among different subsets of primary afferent fibers, several fluorescein-isothiocyanate conjugated lectins were used in a histochemical study of the dorsal root ganglion (DRG) and spinal cord of the rabbit. The lectin Ulex europaeus agglutinin I specifically labeled a subset of DRG cells and primary afferent fibers which projected to the superficial laminae of the dorsal horn. These results suggest that specific carbohydrates containing L-fucosyl residue is expressed selectively in small diameter primary afferent fibers which subserve nociception or thermoception.

Method for data compression by associating complex numbers with files of data values

DOEpatents

Feo, J.T.; Hanks, D.C.; Kraay, T.A.

1998-02-10

A method for compressing data for storage or transmission is disclosed. Given a complex polynomial and a value assigned to each root, a root generated data file (RGDF) is created, one entry at a time. Each entry is mapped to a point in a complex plane. An iterative root finding technique is used to map the coordinates of the point to the coordinates of one of the roots of the polynomial. The value associated with that root is assigned to the entry. An equational data compression (EDC) method reverses this procedure. Given a target data file, the EDC method uses a search algorithm to calculate a set of m complex numbers and a value map that will generate the target data file. The error between a simple target data file and generated data file is typically less than 10%. Data files can be transmitted or stored without loss by transmitting the m complex numbers, their associated values, and an error file whose size is at most one-tenth of the size of the input data file. 4 figs.

Method for data compression by associating complex numbers with files of data values

DOEpatents

Feo, John Thomas; Hanks, David Carlton; Kraay, Thomas Arthur

1998-02-10

A method for compressing data for storage or transmission. Given a complex polynomial and a value assigned to each root, a root generated data file (RGDF) is created, one entry at a time. Each entry is mapped to a point in a complex plane. An iterative root finding technique is used to map the coordinates of the point to the coordinates of one of the roots of the polynomial. The value associated with that root is assigned to the entry. An equational data compression (EDC) method reverses this procedure. Given a target data file, the EDC method uses a search algorithm to calculate a set of m complex numbers and a value map that will generate the target data file. The error between a simple target data file and generated data file is typically less than 10%. Data files can be transmitted or stored without loss by transmitting the m complex numbers, their associated values, and an error file whose size is at most one-tenth of the size of the input data file.

Population calcium imaging of spontaneous respiratory and novel motor activity in the facial nucleus and ventral brainstem in newborn mice

PubMed Central

Persson, Karin; Rekling, Jens C

2011-01-01

Abstract The brainstem contains rhythm and pattern forming circuits, which drive cranial and spinal motor pools to produce respiratory and other motor patterns. Here we used calcium imaging combined with nerve recordings in newborn mice to reveal spontaneous population activity in the ventral brainstem and in the facial nucleus. In Fluo-8 AM loaded brainstem–spinal cord preparations, respiratory activity on cervical nerves was synchronized with calcium signals at the ventrolateral brainstem surface. Individual ventrolateral neurons at the level of the parafacial respiratory group showed perfect or partial synchrony with respiratory nerve bursts. In brainstem–spinal cord preparations, cut at the level of the mid-facial nucleus, calcium signals were recorded in the dorsal, lateral and medial facial subnuclei during respiratory activity. Strong activity initiated in the dorsal subnucleus, followed by activity in lateral and medial subnuclei. Whole-cell recordings from facial motoneurons showed weak respiratory drives, and electrical field potential recordings confirmed respiratory drive to particularly the dorsal and lateral subnuclei. Putative facial premotoneurons showed respiratory-related calcium signals, and were predominantly located dorsomedial to the facial nucleus. A novel motor activity on facial, cervical and thoracic nerves was synchronized with calcium signals at the ventromedial brainstem extending from the level of the facial nucleus to the medulla–spinal cord border. Cervical dorsal root stimulation induced similar ventromedial activity. The medial facial subnucleus showed calcium signals synchronized with this novel motor activity on cervical nerves, and cervical dorsal root stimulation induced similar medial facial subnucleus activity. In conclusion, the dorsal and lateral facial subnuclei are strongly respiratory-modulated, and the brainstem contains a novel pattern forming circuit that drives the medial facial subnucleus and cervical motor pools. PMID:21486812

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.

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

The up-regulation of IL-6 in DRG and spinal dorsal horn contributes to neuropathic pain following L5 ventral root transection.

PubMed

Wei, Xu-Hong; Na, Xiao-Dong; Liao, Guang-Jie; Chen, Qiu-Ying; Cui, Yu; Chen, Feng-Ying; Li, Yong-Yong; Zang, Ying; Liu, Xian-Guo

2013-03-01

Our previous works have shown that pro-inflammatory cytokine tumor necrosis factor-alpha (TNF-α) plays an important role in neuropathic pain produced by lumber 5 ventral root transection (L5-VRT). In the present work we evaluate the role of interleukin-6 (IL-6), another key inflammatory cytokine, in the L5-VRT model. We found that IL-6 was up-regulated in the ipsilateral L4 and L5 dorsal root ganglian (DRG) neurons and in bilateral lumbar spinal cord following L5-VRT. Double immunofluorescence stainings revealed that in DRGs the increased immunoreactivity (IR) of IL-6 was almost restricted in neuronal cells, while in the spinal dorsal horn IL-6-IR up-regulated in both glial cells (astrocyte and microglia) and neurons. Intrathecal administration of IL-6 neutralizing antibody significantly delayed the induction of mechanical allodynia in bilateral hindpaws after L5-VRT. Furthermore, inhibition of TNF-α synthesis by intraperitoneal thalidomide prevented both mechanical allodynia and the up-regulation of IL-6 in DRGs following L5-VRT. These data suggested that the increased IL-6 in afferent neurons and spinal cord contribute to the development of neuropathic pain following motor fiber injury, and that TNF-α is responsible for the up-regulation of IL-6. Copyright © 2012 Elsevier Inc. All rights reserved.

Fragile X mental retardation protein controls synaptic vesicle exocytosis by modulating N-type calcium channel density

NASA Astrophysics Data System (ADS)

Ferron, Laurent; Nieto-Rostro, Manuela; Cassidy, John S.; Dolphin, Annette C.

2014-04-01

Fragile X syndrome (FXS), the most common heritable form of mental retardation, is characterized by synaptic dysfunction. Synaptic transmission depends critically on presynaptic calcium entry via voltage-gated calcium (CaV) channels. Here we show that the functional expression of neuronal N-type CaV channels (CaV2.2) is regulated by fragile X mental retardation protein (FMRP). We find that FMRP knockdown in dorsal root ganglion neurons increases CaV channel density in somata and in presynaptic terminals. We then show that FMRP controls CaV2.2 surface expression by targeting the channels to the proteasome for degradation. The interaction between FMRP and CaV2.2 occurs between the carboxy-terminal domain of FMRP and domains of CaV2.2 known to interact with the neurotransmitter release machinery. Finally, we show that FMRP controls synaptic exocytosis via CaV2.2 channels. Our data indicate that FMRP is a potent regulator of presynaptic activity, and its loss is likely to contribute to synaptic dysfunction in FXS.

The cell surface environment for pathogen recognition and entry.

PubMed

Stow, Jennifer L; Condon, Nicholas D

2016-04-01

The surface of mammalian cells offers an interface between the cell interior and its surrounding milieu. As part of the innate immune system, macrophages have cell surface features optimised for probing and sampling as they patrol our tissues for pathogens, debris or dead cells. Their highly dynamic and constantly moving cell surface has extensions such as lamellipodia, filopodia and dorsal ruffles that help detect pathogens. Dorsal ruffles give rise to macropinosomes for rapid, high volume non-selective fluid sampling, receptor internalisation and plasma membrane turnover. Ruffles can also generate phagocytic cups for the receptor-mediated uptake of pathogens or particles. The membrane lipids, actin cytoskeleton, receptors and signalling proteins that constitute these cell surface domains are discussed. Although the cell surface is designed to counteract pathogens, many bacteria, viruses and other pathogens have evolved to circumvent or hijack these cell structures and their underlying machinery for entry and survival. Nevertheless, these features offer important potential for developing vaccines, drugs and preventative measures to help fight infection.

Exon 11 skipping of SCN10A coding for voltage-gated sodium channels in dorsal root ganglia

PubMed Central

Schirmeyer, Jana; Szafranski, Karol; Leipold, Enrico; Mawrin, Christian; Platzer, Matthias; Heinemann, Stefan H

2014-01-01

The voltage-gated sodium channel NaV1.8 (encoded by SCN10A) is predominantly expressed in dorsal root ganglia (DRG) and plays a critical role in pain perception. We analyzed SCN10A transcripts isolated from human DRGs using deep sequencing and found a novel splice variant lacking exon 11, which codes for 98 amino acids of the domain I/II linker. Quantitative PCR analysis revealed an abundance of this variant of up to 5–10% in human, while no such variants were detected in mouse or rat. Since no obvious functional differences between channels with and without the exon-11 sequence were detected, it is suggested that SCN10A exon 11 skipping in humans is a tolerated event. PMID:24763188

Effect of Acycloguanosine Treatment on Acute and Latent Herpes Simplex Infections in Mice

PubMed Central

Field, Hugh J.; Bell, Susanne E.; Elion, Gertrude B.; Nash, Anthony A.; Wildy, Peter

1979-01-01

Systemic treatment of mice with the nucleoside analog 9-(2-hydroxyethoxymethyl)guanine (acycloguanosine [aciclovir]) was found to be highly effective against acute type 1 herpes simplex virus infection of the pinna. The drug ablated clinical signs and reduced virus replication both in tissue local to the inoculation site and within the nervous system. Provided that moderate-sized virus inocula were used, acycloguanosine treatment reduced or prevented the establishment of a latent infection in the dorsal root ganglia relating to the sensory nerve supply of the ear. However, although it aborted artificially produced infections in dorsal root ganglia, acycloguanosine was found not to be effective against the latent infection once established. This finding strongly indicated that latent herpes simplex virus in mice can exist in a nonreplicating form. PMID:464587

Effect of acycloguanosine treatment of acute and latent herpes simplex infections in mice.

PubMed

Field, H J; Bell, S E; Elion, G B; Nash, A A; Wildy, P

1979-04-01

Systemic treatment of mice with the nucleoside analog 9-(2-hydroxyethoxymethyl)guanine (acycloguanosine [aciclovir]) was found to be highly effective against acute type 1 herpes simplex virus infection of the pinna. The drug ablated clinical signs and reduced virus replication both in tissue local to the inoculation site and within the nervous system. Provided that moderate-sized virus inocula were used, acycloguanosine treatment reduced or prevented the establishment of a latent infection in the dorsal root ganglia relating to the sensory nerve supply of the ear. However, although it aborted artificially produced infections in dorsal root ganglia, acycloguanosine was found not to be effective against the latent infection once established. This finding strongly indicated that latent herpes simplex virus in mice can exist in a nonreplicating form.

Models of Inflammation: Carrageenan- or Complete Freund's Adjuvant (CFA)-Induced Edema and Hypersensitivity in the Rat.

PubMed

McCarson, Kenneth E

2015-09-01

Animal models of inflammation are used to assess the production of inflammatory mediators at sites of inflammation, the processing of pain sensation at CNS sites, the anti-inflammatory properties of agents such as nonsteroidal anti-inflammatory drugs (NSAIDs), and the efficacy of putative analgesic compounds in reversing cutaneous hypersensitivity. Detailed in this unit are methods to elicit and measure carrageenan- and complete Freund's adjuvant (CFA)-induced cutaneous inflammation. Due to possible differences between the dorsal root sensory system and the trigeminal sensory system, injections into either the footpad or vibrissal pad are described. In this manner, cutaneous inflammation can be assessed in tissue innervated by the lumbar dorsal root ganglion neurons (footpad) or by the trigeminal ganglion neurons (vibrissal pad). Copyright © 2015 John Wiley & Sons, Inc.

Expression of the vesicular glutamate transporters-1 and -2 in adult mouse dorsal root ganglia and spinal cord and their regulation by nerve injury.

PubMed

Brumovsky, P; Watanabe, M; Hökfelt, T

2007-06-29

The expression of two vesicular glutamate transporters (VGLUTs), VGLUT1 and VGLUT2, was studied with immunohistochemistry in lumbar dorsal root ganglia (DRGs), the lumbar spinal cord and the skin of the adult mouse. About 12% and 65% of the total number of DRG neuron profiles (NPs) expressed VGLUT1 and VGLUT2, respectively. VGLUT1-immunoreactive (IR) NPs were usually medium- to large-sized, in contrast to a majority of small- or medium-sized VGLUT2-IR NPs. Most VGLUT1-IR NPs did not coexpress calcitonin gene-related peptide (CGRP) or bound isolectin B4 (IB4). In contrast, approximately 31% and approximately 42% of the VGLUT2-IR DRG NPs were also CGRP-IR or bound IB4, respectively. Conversely, virtually all CGRP-IR and IB4-binding NPs coexpressed VGLUT2. Moderate colocalization between VGLUT1 and VGLUT2 was also observed. Sciatic nerve transection induced a decrease in the overall number of VGLUT1- and VGLUT2-IR NPs (both ipsi- and contralaterally) and, in addition, a parallel, unilateral increase of VGLUT2-like immunoreactivity (LI) in a subpopulation of mostly small NPs. In the dorsal horn of the spinal cord, strong VGLUT1-LI was detected, particularly in deep dorsal horn layers and in the ventral horns. VGLUT2-LI was abundant throughout the gray spinal matter, 'radiating' into/from the white matter. A unilateral dorsal rhizotomy reduced VGLUT1-LI, while apparently leaving unaffected the VGLUT2-LI. Transport through axons for both VGLUTs was confirmed by their accumulation after compression of the sciatic nerve or dorsal roots. In the hind paw skin, abundant VGLUT2-IR nerve fibers were observed, sometimes associated with Merkel cells. Lower numbers of VGLUT1-IR fibers were also detected in the skin. Some VGLUT1-IR and VGLUT2-IR fibers were associated with hair follicles. Based on these data and those by Morris et al. [Morris JL, Konig P, Shimizu T, Jobling P, Gibbins IL (2005) Most peptide-containing sensory neurons lack proteins for exocytotic release and vesicular transport of glutamate. J Comp Neurol 483:1-16], we speculate that virtually all DRG neurons in adult mouse express VGLUTs and use glutamate as transmitter.

Safe insertion of S-2 alar iliac screws: radiological comparison between 2 insertion points using computed tomography and 3D analysis software.

PubMed

Yamada, Kentaro; Abe, Yuichiro; Satoh, Shigenobu

2018-05-01

OBJECTIVE S-2 alar iliac (S2AI) screws are commonly used as anchors for lumbosacral fixation. A serious potential complication of screw insertion is major vascular injury due to anterior or caudal screw deviation. To avoid screw deviation, the pelvic inlet view on intraoperative fluoroscopy images is recommended. However, there has been no detailed investigation of optimal fluoroscopic incline with the pelvic inlet view. The purpose of this study was to investigate the safety margins and to optimize fluoroscopic settings to avoid screw deviation with 2 reported insertion techniques using 3D analysis software and CT. METHODS The study included 50 patients (25 men and 25 women) who underwent abdominal-pelvic CT. With the use of software, the ideal S2AI screws were set from 2 entry points: A) the midpoint between the S-1 dorsal foramen and the S-2 dorsal foramen where they meet the lateral sacral crest, and B) 1 mm inferior and 1 mm lateral to the S-1 dorsal foramen. Anteriorly or caudally deviated screws were defined as deviation of a half thread of the ideal screw by rotation anteriorly or caudally from the entry point. The angular safety margins were compared between the 2 entry points, and patients with small safety margins were investigated. Subsequently, fluoroscopic images were virtualized on ray sum-rendered images. Conditions that provided proper recognition of screw deviation were investigated via lateral and anteroposterior views with the beam tilted caudally. RESULTS The safety margins of S2AI screws were smaller in the anterior direction than in the caudal direction and by entry point A than by entry point B (A: 9.1° ± 1.6° and B: 9.7° ± 1.5° in the anterior direction; A: 10.9° ± 3.8° and B: 13.9° ± 4.1° in the caudal direction). In contrast, patients with a deep-seated L-5 vertebral body tended to have smaller safety margins in the caudal direction. All anteriorly deviated screws were recognized with a 60°-70° inlet view from the S-1 slope. The caudally deviated screws were all recognized on the lateral view, but 31% of screws at entry point A and 21% of screws at entry point B were not recognized on the pelvic inlet view. CONCLUSIONS S2AI screws should be carefully placed to avoid anterior deviation compared with caudal deviation in terms of the safety margin, except in patients with a deep-seated L-5. The difference in safety margins between entry points A and B was negligible. Intraoperative fluoroscopy is recommended with a pelvic inlet view tilted 60°-70° from the S-1 slope to avoid anterior screw deviation. The lateral view is recommended to confirm that the screw is not deviated caudally.

Application of a fast skyline computation algorithm for serendipitous searching problems

NASA Astrophysics Data System (ADS)

Koizumi, Kenichi; Hiraki, Kei; Inaba, Mary

2018-02-01

Skyline computation is a method of extracting interesting entries from a large population with multiple attributes. These entries, called skyline or Pareto optimal entries, are known to have extreme characteristics that cannot be found by outlier detection methods. Skyline computation is an important task for characterizing large amounts of data and selecting interesting entries with extreme features. When the population changes dynamically, the task of calculating a sequence of skyline sets is called continuous skyline computation. This task is known to be difficult to perform for the following reasons: (1) information of non-skyline entries must be stored since they may join the skyline in the future; (2) the appearance or disappearance of even a single entry can change the skyline drastically; (3) it is difficult to adopt a geometric acceleration algorithm for skyline computation tasks with high-dimensional datasets. Our new algorithm called jointed rooted-tree (JR-tree) manages entries using a rooted tree structure. JR-tree delays extend the tree to deep levels to accelerate tree construction and traversal. In this study, we presented the difficulties in extracting entries tagged with a rare label in high-dimensional space and the potential of fast skyline computation in low-latency cell identification technology.

Inhibition of tetrodotoxin-resistant sodium current in dorsal root ganglia neurons mediated by D1/D5 dopamine receptors

PubMed Central

2013-01-01

Background Dopaminergic fibers originating from area A11 of the hypothalamus project to different levels of the spinal cord and represent the major source of dopamine. In addition, tyrosine hydroxylase, the rate-limiting enzyme for the synthesis of catecholamines, is expressed in 8-10% of dorsal root ganglia (DRG) neurons, suggesting that dopamine may be released in the dorsal root ganglia. Dopamine has been shown to modulate calcium current in DRG neurons, but the effects of dopamine on sodium current and on the firing properties of small DRG neurons are poorly understood. Results The effects of dopamine and dopamine receptor agonists were tested on the tetrodotoxin-resistant (TTX-R) sodium current recorded from acutely dissociated small (diameter ≤ 25 μm) DRG neurons. Dopamine (20 μM) and SKF 81297 (10 μM) caused inhibition of TTX-R sodium current in small DRG neurons by 23% and 37%, respectively. In contrast, quinpirole (20 μM) had no effects on the TTX-R sodium current. Inhibition by SKF 81297 of the TTX-R sodium current was not affected when the protein kinase A (PKA) activity was blocked with the PKA inhibitory peptide (6–22), but was greatly reduced when the protein kinase C (PKC) activity was blocked with the PKC inhibitory peptide (19–36), suggesting that activation of D1/D5 dopamine receptors is linked to PKC activity. Expression of D1and D5 dopamine receptors in small DRG neurons, but not D2 dopamine receptors, was confirmed by Western blotting and immunofluorescence analysis. In current clamp experiments, the number of action potentials elicited in small DRG neurons by current injection was reduced by ~ 30% by SKF 81297. Conclusions We conclude that activation of D1/D5 dopamine receptors inhibits TTX-R sodium current in unmyelinated nociceptive neurons and dampens their intrinsic excitability by reducing the number of action potentials in response to stimulus. Increasing or decreasing levels of dopamine in the dorsal root ganglia may serve to adjust the sensitivity of nociceptors to noxious stimuli. PMID:24283218

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.

Sex differences in pain-related behavior and expression of calcium/calmodulin-dependent protein kinase II in dorsal root ganglia of rats with diabetes type 1 and type 2.

PubMed

Ferhatovic, Lejla; Banozic, Adriana; Kostic, Sandra; Sapunar, Damir; Puljak, Livia

2013-06-01

Sex differences in pain-related behavior and expression of calcium/calmodulin dependent protein kinase II (CaMKII) in dorsal root ganglia were studied in rat models of Diabetes mellitus type 1 (DM1) and type 2 (DM2). DM1 was induced with 55mg/kg streptozotocin, and DM2 with a combination of high-fat diet and 35mg/kg of streptozotocin. Pain-related behavior was analyzed using thermal and mechanical stimuli. The expression of CaMKII was analyzed with immunofluorescence. Sexual dimorphism in glycemia, and expression of CaMKII was observed in the rat model of DM1, but not in DM2 animals. Increased expression of total CaMKII (tCaMKII) in small-diameter dorsal root ganglia neurons, which are associated with nociception, was found only in male DM1 rats. None of the animals showed increased expression of the phosphorylated alpha CaMKII isoform in small-diameter neurons. The expression of gamma and delta isoforms of CaMKII remained unchanged in all analyzed animal groups. Different patterns of glycemia and tCaMKII expression in male and female model of DM1 were not associated with sexual dimorphism in pain-related behavior. The present findings do not suggest sex-related differences in diabetic painful peripheral neuropathy in male and female diabetic rats. Copyright © 2012 Elsevier GmbH. All rights reserved.

Capsaicin-sensitive muscle afferents modulate the monosynaptic reflex in response to muscle ischemia and fatigue in the rat.

PubMed

Della Torre, G; Brunetti, O; Pettorossi, V E

2002-01-01

The role of muscle ischemia and fatigue in modulating the monosynaptic reflex was investigated in decerebrate and spinalized rats. Field potentials and fast motoneuron single units in the lateral gastrocnemious (LG) motor pool were evoked by dorsal root stimulation. Muscle ischemia was induced by occluding the LG vascular supply and muscle fatigue by prolonged tetanic electrical stimulation of the LG motor nerve. Under muscle ischemia the monosynaptic reflex was facilitated since the size of the early and late waves of the field potential and the excitability of the motoneuron units increased. This effect was abolished after L3-L6 dorsal rhizotomy, but it was unaffected after L3-L6 ventral rhizotomy. By contrast, the monosynaptic reflex was inhibited by muscle fatiguing stimulation, and this effect did not fully depend on the integrity of the dorsal root. However, when ischemia was combined with repetitive tetanic muscle stimulation the inhibitory effect of fatigue was significantly enhanced. Both the ischemia and fatigue effects were abolished by capsaicin injected into the LG muscle at a dose that blocked a large number of group III and IV muscle afferents. We concluded that muscle ischemia and fatigue activate different groups of muscle afferents that are both sensitive to capsaicin, but enter the spinal cord through different roots. They are responsible for opposite effects, when given separately: facilitation during ischemia and inhibition during fatigue; however, in combination, ischemia enhances the responsiveness of the afferent fibres to fatigue.

Real-time control of walking using recordings from dorsal root ganglia

PubMed Central

Holinski, B J; Everaert, D G; Mushahwar, V K; Stein, R B

2013-01-01

Objective The goal of this study was to decode sensory information from the dorsal root ganglia (DRG) in real time, and to use this information to adapt the control of unilateral stepping with a state-based control algorithm consisting of both feed-forward and feedback components. Approach In five anesthetized cats, hind limb stepping on a walkway or treadmill was produced by patterned electrical stimulation of the spinal cord through implanted microwire arrays, while neuronal activity was recorded from the dorsal root ganglia. Different parameters, including distance and tilt of the vector between hip and limb endpoint, integrated gyroscope and ground reaction force were modeled from recorded neural firing rates. These models were then used for closed-loop feedback. Main Results Overall, firing-rate based predictions of kinematic sensors (limb endpoint, integrated gyroscope) were the most accurate with variance accounted for >60% on average. Force prediction had the lowest prediction accuracy (48±13%) but produced the greatest percentage of successful rule activations (96.3%) for stepping under closed-loop feedback control. The prediction of all sensor modalities degraded over time, with the exception of tilt. Significance Sensory feedback from moving limbs would be a desirable component of any neuroprosthetic device designed to restore walking in people after a spinal cord injury. This study provides a proof-of-principle that real-time feedback from the DRG is possible and could form part of a fully implantable neuroprosthetic device with further development. PMID:23928579

Long term effects of lipopolysaccharide on satellite glial cells in mouse dorsal root ganglia

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

Blum, E.; Procacci, P.; Conte, V.

Lipopolysaccharide (LPS) has been used extensively to study neuroinflammation, but usually its effects were examined acutely (24 h<). We have shown previously that a single intraperitoneal LPS injection activated satellite glial cells (SGCs) in mouse dorsal root ganglia (DRG) and altered several functional parameters in these cells for at least one week. Here we asked whether the LPS effects would persist for 1 month. We injected mice with a single LPS dose and tested pain behavior, assessed SGCs activation in DRG using glial fibrillary acidic protein (GFAP) immunostaining, and injected a fluorescent dye intracellularly to study intercellular coupling. Electron microscopymore » was used to quantitate changes in gap junctions. We found that at 30 days post-LPS the threshold to mechanical stimulation was lower than in controls. GFAP expression, as well as the magnitude of dye coupling among SGCs were greater than in controls. Electron microscopy analysis supported these results, showing a greater number of gap junctions and an abnormal growth of SGC processes. These changes were significant, but less prominent than at 7 days post-LPS. We conclude that a single LPS injection exerts long-term behavioral and cellular changes. The results are consistent with the idea that SGC activation contributes to hyperalgesia. - Highlights: • A single lipopolysaccharides injection activated glia in mouse dorsal root ganglia for 30 days. • This was accompanied by increased communications by gap junctions among glia and by hyperalgesia. • Glial activation and coupling may contribute to chronic pain.« less

α-Synuclein pathology in the cranial and spinal nerves in Lewy body disease.

PubMed

Nakamura, Keiko; Mori, Fumiaki; Tanji, Kunikazu; Miki, Yasuo; Toyoshima, Yasuko; Kakita, Akiyoshi; Takahashi, Hitoshi; Yamada, Masahito; Wakabayashi, Koichi

2016-06-01

Accumulation of phosphorylated α-synuclein in neurons and glial cells is a histological hallmark of Lewy body disease (LBD) and multiple system atrophy (MSA). Recently, filamentous aggregations of phosphorylated α-synuclein have been reported in the cytoplasm of Schwann cells, but not in axons, in the peripheral nervous system in MSA, mainly in the cranial and spinal nerve roots. Here we conducted an immunohistochemical investigation of the cranial and spinal nerves and dorsal root ganglia of patients with LBD. Lewy axons were found in the oculomotor, trigeminal and glossopharyngeal-vagus nerves, but not in the hypoglossal nerve. The glossopharyngeal-vagus nerves were most frequently affected, with involvement in all of 20 subjects. In the spinal nerve roots, Lewy axons were found in all of the cases examined. Lewy axons in the anterior nerves were more frequent and numerous in the thoracic and sacral segments than in the cervical and lumbar segments. On the other hand, axonal lesions in the posterior spinal nerve roots appeared to increase along a cervical-to-sacral gradient. Although Schwann cell cytoplasmic inclusions were found in the spinal nerves, they were only minimal. In the dorsal root ganglia, axonal lesions were seldom evident. These findings indicate that α-synuclein pathology in the peripheral nerves is axonal-predominant in LBD, whereas it is restricted to glial cells in MSA. © 2015 Japanese Society of Neuropathology.

[Curcumin down-regulates CX3CR1 expression in spinal cord dorsal horn and DRG in neuropathic pain rats].

PubMed

Zheng, Jinwei; Zheng, Changjian; Cao, Hong; Li, Jun; Lian, Qingquan

2011-09-01

To investigate the effects of curcumin on the behavior of chronic constrictive injury (CCI) rats and the CX3CR1 expression in spinal cord dorsal horn and dorsal root ganglia (DRG). Seventy-two male SD rats were randomly divided into 4 groups: 1) Sham operation group (Sham); 2) Chronic constrictive injury group (CCI); 3) Curcumin treated group (Cur), administrated with curcumin 100 mg x kg(-1) x d(-1) ip for 14 days after CCI; 4) Solvent contrast group (SC), administrated with an equal volume of solvent for 14 days after CCI. Paw thermal withdrawal (PTWL) and paw mechanical withdrawal threshold (PMWT) were measured on 2 pre-operative and 1, 3, 5, 7, 10, 14 post-operative days respectively. The lumbar segments L4-5 of the spinal cord and the L4, L5 DRG were removed at 3, 7, 14 days after surgery. The expression of CX3CR1 was determined by immunohistochemical staining. Compared with Sham group, PTWL and PMWT in CCI group were significantly lower on each post-operative day (P<0.01), which reached a nadir on the 3rd day after CCI (PTWL was 6.5 +/- 1.1, PMWT was 22.6 +/- 5.1), and the expression of CX3CR1 were markedly increased in spinal cord dorsal horn and DRG. In Cur group, PTWL were higher than in CCI group on 7, 10, 14 post-operative day (P<0.05), and PMWT were higher than those in CCI group on 10 and 14 post-operative day (P<0.05). The administration of curcumin could significantly attenuate the activation of CX3CR1 induced by CCI. The study suggests that curcumin ameliorates the CCI-induced neuropathic pain, probably by attenuating the expression of CX3CR1 in spinal cord dorsal horn and dorsal root ganglia.

[Upregulation of P2X3 receptors in dorsal root ganglion of TRPV1 knockout female mice].

PubMed

Fang, Xiao; Shi, Xiao-Han; Huang, Li-Bin; Rong, Wei-Fang; Ma, Bei

2014-08-25

The study was aimed to investigate the changes in mechanical pain threshold in the condition of chronic inflammatory pain after transient receptor potential vanilloid 1 (TRPV1) gene was knockout. Hind-paw intraplantar injection of complete freund's adjuvant (CFA, 20 μL) produced peripheral inflammation in wild-type and TRPV1 knockout female mice. The mechanical pain thresholds were measured during the 8 days after injection and pre-injection by using Von-Frey hair. Nine days after injection, mice were killed and the differences of expression of c-Fos and P2X3 receptor in the dorsal root ganglia (DRG) and spinal cord dorsal horn were examined by Western blotting between the two groups. Compared with that in wild-type mice, the mechanical pain threshold was increased significantly in TRPV1 knockout mice (P < 0.05); 3 days after CFA injection, the baseline mechanical pain threshold in the TRPV1 knockout mice group was significantly higher than that in the wild-type mice group (P < 0.05); The result of Western blotting showed that the expression of c-Fos protein both in DRG and spinal cord dorsal horn of TRPV1 knockout mice group was decreased significantly compared with that in wild-type mice group (P < 0.01, P < 0.05), while the expression of P2X3 receptor in DRG of TRPV1 knockout mice group was increased significantly compared with that in wild-type mice group (P < 0.05). Our findings indicate that TRPV1 may influence the peripheral mechanical pain threshold by mediating the expression of c-Fos protein both in DRG and spinal cord dorsal horn and changing the expression of P2X3 receptor in DRG.

Resistance to Southern Root-knot Nematode (Meloidogyne incognita) in Wild Watermelon (Citrullus lanatus var. citroides)

PubMed Central

Thies, Judy A.; Ariss, Jennifer J.; Kousik, Chandrasekar S.; Hassell, Richard L.; Levi, Amnon

2016-01-01

Southern root-knot nematode (RKN, Meloidogyne incognita) is a serious pest of cultivated watermelon (Citrullus lanatus var. lanatus) in southern regions of the United States and no resistance is known to exist in commercial watermelon cultivars. Wild watermelon relatives (Citrullus lanatus var. citroides) have been shown in greenhouse studies to possess varying degrees of resistance to RKN species. Experiments were conducted over 2 yr to assess resistance of southern RKN in C. lanatus var. citroides accessions from the U.S. Watermelon Plant Introduction Collection in an artificially infested field site at the U.S. Vegetable Laboratory in Charleston, SC. In the first study (2006), 19 accessions of C. lanatus var. citroides were compared with reference entries of Citrullus colocynthis and C. lanatus var. lanatus. Of the wild watermelon accessions, two entries exhibited significantly less galling than all other entries. Five of the best performing C. lanatus var. citroides accessions were evaluated with and without nematicide at the same field site in 2007. Citrullus lanatus var. citroides accessions performed better than C. lanatus var. lanatus and C. colocynthis. Overall, most entries of C. lanatus var. citroides performed similarly with and without nematicide treatment in regard to root galling, visible egg masses, vine vigor, and root mass. In both years of field evaluations, most C. lanatus var. citroides accessions showed lesser degrees of nematode reproduction and higher vigor and root mass than C. colocynthis and C. lanatus var. lanatus. The results of these two field evaluations suggest that wild watermelon populations may be useful sources of resistance to southern RKN. PMID:27168648

Resistance to Southern Root-knot Nematode (Meloidogyne incognita) in Wild Watermelon (Citrullus lanatus var. citroides).

PubMed

Thies, Judy A; Ariss, Jennifer J; Kousik, Chandrasekar S; Hassell, Richard L; Levi, Amnon

2016-03-01

Southern root-knot nematode (RKN, Meloidogyne incognita) is a serious pest of cultivated watermelon (Citrullus lanatus var. lanatus) in southern regions of the United States and no resistance is known to exist in commercial watermelon cultivars. Wild watermelon relatives (Citrullus lanatus var. citroides) have been shown in greenhouse studies to possess varying degrees of resistance to RKN species. Experiments were conducted over 2 yr to assess resistance of southern RKN in C. lanatus var. citroides accessions from the U.S. Watermelon Plant Introduction Collection in an artificially infested field site at the U.S. Vegetable Laboratory in Charleston, SC. In the first study (2006), 19 accessions of C. lanatus var. citroides were compared with reference entries of Citrullus colocynthis and C. lanatus var. lanatus. Of the wild watermelon accessions, two entries exhibited significantly less galling than all other entries. Five of the best performing C. lanatus var. citroides accessions were evaluated with and without nematicide at the same field site in 2007. Citrullus lanatus var. citroides accessions performed better than C. lanatus var. lanatus and C. colocynthis. Overall, most entries of C. lanatus var. citroides performed similarly with and without nematicide treatment in regard to root galling, visible egg masses, vine vigor, and root mass. In both years of field evaluations, most C. lanatus var. citroides accessions showed lesser degrees of nematode reproduction and higher vigor and root mass than C. colocynthis and C. lanatus var. lanatus. The results of these two field evaluations suggest that wild watermelon populations may be useful sources of resistance to southern RKN.

Gastric Electrical Stimulation Decreases Gastric Distension-Induced Central Nociception Response through Direct Action on Primary Afferents

PubMed Central

Ouelaa, Wassila; Ghouzali, Ibtissem; Langlois, Ludovic; Fetissov, Serguei; Déchelotte, Pierre; Ducrotté, Philippe; Leroi, Anne Marie; Gourcerol, Guillaume

2012-01-01

Background & Aims Gastric electrical stimulation (GES) is an effective therapy to treat patients with chronic dyspepsia refractory to medical management. However, its mechanisms of action remain poorly understood. Methods Gastric pain was induced by performing gastric distension (GD) in anesthetized rats. Pain response was monitored by measuring the pseudo-affective reflex (e.g., blood pressure variation), while neuronal activation was determined using c-fos immunochemistry in the central nervous system. Involvement of primary afferents was assessed by measuring phosphorylation of ERK1/2 in dorsal root ganglia. Results GES decreased blood pressure variation induced by GD, and prevented GD-induced neuronal activation in the dorsal horn of the spinal cord (T9–T10), the nucleus of the solitary tract and in CRF neurons of the hypothalamic paraventricular nucleus. This effect remained unaltered within the spinal cord when sectioning the medulla at the T5 level. Furthermore, GES prevented GD-induced phosphorylation of ERK1/2 in dorsal root ganglia. Conclusions GES decreases GD-induced pain and/or discomfort likely through a direct modulation of gastric spinal afferents reducing central processing of visceral nociception. PMID:23284611

Noxious mechanical heterotopic stimulation induces inhibition of the spinal dorsal horn neuronal network: analysis of spinal somatosensory-evoked potentials.

PubMed

Meléndez-Gallardo, J; Eblen-Zajjur, A

2016-09-01

Most of the endogenous pain modulation (EPM) involves the spinal dorsal horn (SDH). EPM including diffuse noxious inhibitory controls have been extensively described in oligoneuronal electrophysiological recordings but less attention had been paid to responses of the SDH neuronal population to heterotopic noxious stimulation (HNS). Spinal somatosensory-evoked potentials (SEP) offer the possibility to evaluate the neuronal network behavior, reflecting the incoming afferent volleys along the entry root, SDH interneuron activities and the primary afferent depolarization. SEP from de lumbar cord dorsum were evaluated during mechanical heterotopic noxious stimuli. Sprague-Dawley rats (n = 12) were Laminectomized (T10-L3). The sural nerve of the left hind paw was electrically stimulated (5 mA, 0.5 ms, 0.05 Hz) to induce lumbar SEP. The HNS (mechanic clamp) was applied sequentially to the tail, right hind paw, right forepaw, muzzle and left forepaw during sural stimulation. N wave amplitude decreases (-16.6 %) compared to control conditions when HNS was applied to all areas of stimulation. This effect was more intense for muzzle stimulation (-23.5 %). N wave duration also decreased by -23.6 %. HNS did not change neither the amplitude nor the duration of the P wave but dramatically increases the dispersion of these two parameters. The results of the present study strongly suggest that a HNS applied to different parts of the body is able to reduce the integrated electrical response of the SDH, suggesting that not only wide dynamic range neurons but many others in the SDH are modulated by the EPM.

Altitude control in honeybees: joint vision-based learning and guidance.

PubMed

Portelli, Geoffrey; Serres, Julien R; Ruffier, Franck

2017-08-23

Studies on insects' visual guidance systems have shed little light on how learning contributes to insects' altitude control system. In this study, honeybees were trained to fly along a double-roofed tunnel after entering it near either the ceiling or the floor of the tunnel. The honeybees trained to hug the ceiling therefore encountered a sudden change in the tunnel configuration midways: i.e. a "dorsal ditch". Thus, the trained honeybees met a sudden increase in the distance to the ceiling, corresponding to a sudden strong change in the visual cues available in their dorsal field of view. Honeybees reacted by rising quickly and hugging the new, higher ceiling, keeping a similar forward speed, distance to the ceiling and dorsal optic flow to those observed during the training step; whereas bees trained to follow the floor kept on following the floor regardless of the change in the ceiling height. When trained honeybees entered the tunnel via the other entry (the lower or upper entry) to that used during the training step, they quickly changed their altitude and hugged the surface they had previously learned to follow. These findings clearly show that trained honeybees control their altitude based on visual cues memorized during training. The memorized visual cues generated by the surfaces followed form a complex optic flow pattern: trained honeybees may attempt to match the visual cues they perceive with this memorized optic flow pattern by controlling their altitude.

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

Accumulation of immunoglobulin G against Dermatophagoides farinae tropomyosin in dorsal root ganglia of NC/Nga mice with atopic dermatitis-like symptoms.

PubMed

Otsu, Ayaka; Kawasaki, Hiroaki; Tominaga, Mitsutoshi; Shigenaga, Ayako; Matsuda, Hironori; Takahashi, Nobuaki; Nakajima, Tadaaki; Naito, Hisashi; Baba, Takeshi; Ogawa, Hideoki; Tomooka, Yasuhiro; Yamakura, Fumiyuki; Takamori, Kenji

2017-04-15

Atopic dermatitis (AD), a chronic inflammatory skin disease, manifests as intractable itch, but its underlying mechanisms are poorly understood. This study assessed the relationship between immunoglobulin G (IgG) and dorsal root ganglia (DRG) in NC/Nga mice, a model of AD that manifests AD-like symptoms including itch. Immunohistochemical analysis showed large amounts of IgG in DRG extracts of NC/Nga mice with AD-like dermatitis, with a large fraction of the IgG distributed in satellite glial cells of the DRG. Proteomic analysis showed that this IgG was reactive against tropomyosin of Dermatophagoides farinae. These findings indicate that the accumulation of anti-tropomyosin IgG in DRG of atopic NC/Nga mice may be associated with the pathogenesis of AD-like symptoms, including itch. Copyright © 2017 Elsevier Inc. All rights reserved.

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.

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.

Blackfoot Dictionary of Stems, Roots, and Affixes. Second Edition.

ERIC Educational Resources Information Center

Frantz, Donald G.; Russell, Norma Jean

The dictionary of stems, roots, and affixes for the Blackfoot language provides, for each entry, information on the item's morphological type (e.g., noun stem, verb stem, root), subclassification if relevant, English index, and certain diagnostic inflectional forms (full words or sentences), each with an English translation. In addition, entries…

Surface localization of sacral foramina for neuromodulation of bladder function. An anatomical study.

PubMed

Hasan, S T; Shanahan, D A; Pridie, A K; Neal, D E

1996-01-01

A method is described for percutaneous localization of the sacral foramina, for neuromodulation of bladder function. We carried out an anatomical study of 5 male and 5 female human cadaver pelves. Using the described surface markings, needles were placed percutaneously into all sacral foramina from nine different angles. Paths of needle entry were studied by subsequent dissection. We observed that although it was possible to enter any sacral foramen at a wide range of insertion angles, the incidence of nerve root/vascular penetration increased with increasing angle of needle entry. Also, the incidence of nerve root penetration was higher with the medial approach compared with lateral entry. The insertion of a needle into the S1 foramen was associated with a higher incidence of nerve root penetration and presents a potential for arterial haemorrhage. On the other hand the smaller S3 and S4 nerve roots were surrounded by venous plexuses, presenting a potential source of venous haemorrhage during procedures. Our study suggests a new method for identifying the surface markings of sacral foramina and it describes the paths of inserted needles into the respective foramina. In addition, it has highlighted some potential risk factors secondary to needle insertion.

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.

Single Administration of Melatonin Modulates the Nitroxidergic System at the Peripheral Level and Reduces Thermal Nociceptive Hypersensitivity in Neuropathic Rats.

PubMed

Borsani, Elisa; Buffoli, Barbara; Bonazza, Veronica; Reiter, Russel J; Rezzani, Rita; Rodella, Luigi F

2017-10-14

Neuropathic pain is a severe condition with unsatisfactory treatments. Melatonin, an indolamine, seems to be a promising molecule suitable for this purpose due to its well-known anti-inflammatory, analgesic, and antioxidant effects, as well as its modulation of the nitroxidergic system. Nevertheless, the data on its mechanism of action and potentialities are currently insufficient in this pathology, especially at the peripheral level. Thus, this work evaluated the effect of a single administration of melatonin in an established mononeuropathy pain model that monitors the behaviour and the changes in the nitroxidergic system in dorsal root ganglia and skin, which are affected by nervous impairment. Experiments were carried out on Sprague Dawley rats subdivided into the sham operated (control) and the chronic constriction injured animals, a model of peripheral neuropathic pain on sciatic nerve. Single administrations of melatonin (5-10 mg/kg) or vehicle were injected intraperitoneally on the 14th day after surgery, when the mononeuropathy was established. The animals were behaviourally tested for thermal hyperalgesia. The dorsal root ganglia and the plantar skin of the hind-paws were removed and processed for the immunohistochemical detection of neuronal and inducible nitric oxide synthases. The behavioural results showed an increase of withdrawal latency during the plantar test as early as 30 min after melatonin administration. The immunohistochemical results indicated a modulation of the nitroxidergic system both at dorsal root ganglia and skin level, permitting speculate on a possible mechanism of action. We showed that melatonin may be a possible therapeutic strategy in neuropathic pain.

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.

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

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

Three types of neuronal calcium channel with different calcium agonist sensitivity.

PubMed

Nowycky, M C; Fox, A P; Tsien, R W

How many types of calcium channels exist in neurones? This question is fundamental to understanding how calcium entry contributes to diverse neuronal functions such as transmitter release, neurite extension, spike initiation and rhythmic firing. There is considerable evidence for the presence of more than one type of Ca conductance in neurones and other cells. However, little is known about single-channel properties of diverse neuronal Ca channels, or their responsiveness to dihydropyridines, compounds widely used as labels in Ca channel purification. Here we report evidence for the coexistence of three types of Ca channel in sensory neurones of the chick dorsal root ganglion. In addition to a large conductance channel that contributes long-lasting current at strong depolarizations (L), and a relatively tiny conductance that underlies a transient current activated at weak depolarizations (T), we find a third type of unitary activity (N) that is neither T nor L. N-type Ca channels require strongly negative potentials for complete removal of inactivation (unlike L) and strong depolarizations for activation (unlike T). The dihydropyridine Ca agonist Bay K 8644 strongly increases the opening probability of L-, but not T- or N-type channels.

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 constant after each subsequent radiofrequency treatment. Of the 50 total patients, there was only 1 reported complication, specifically, transient thigh numbness which resolved after one week. Repeated pulsed and continuous radiofrequency ablation of the lumbar dorsal root ganglion/segmental nerve shows promise to be a safe and effective long-term palliative management for lumbosacral radicular pain in some patients.

Retrograde and transganglionic transport of horseradish peroxidase-conjugated cholera toxin B subunit, wheatgerm agglutinin and isolectin B4 from Griffonia simplicifolia I in primary afferent neurons innervating the rat urinary bladder.

PubMed

Wang, H F; Shortland, P; Park, M J; Grant, G

1998-11-01

In the present study, we investigated and compared the ability of the cholera toxin B subunit, wheat germ agglutinin and isolectin B4 from Griffonia simplicifolia I conjugated to horseradish peroxidase, to retrogradely and transganglionically label visceral primary afferents after unilateral injections into the rat urinary bladder wall. Horseradish peroxidase histochemical or lectin-immunofluorescence histochemical labelling of bladder afferents was seen in the L6-S1 spinal cord segments and in the T13-L2 and L6-S1 dorsal root ganglia. In the lumbosacral spinal cord, the most intense and extensive labelling of bladder afferents was seen when cholera toxin B subunit-horseradish peroxidase was injected. Cholera toxin B subunit-horseradish peroxidase-labelled fibres were found in Lissauer's tract, its lateral and medial collateral projections, and laminae I and IV-VI of the spinal gray matter. Labelled fibres were numerous in the lateral collateral projection and extended into the spinal parasympathetic nucleus. Labelling from both the lateral and medial projections extended into the dorsal grey commissural region. Wheat germ agglutinin-horseradish peroxidase labelling produced a similar pattern but was not as dense and extensive as that of cholera toxin B subunit-horseradish peroxidase. The isolectin B4 from Griffonia simplicifolia I-horseradish peroxidase-labelled fibres, on the other hand, were fewer and only observed in the lateral collateral projection and occasionally in lamina I. Cell profile counts showed that a larger number of dorsal root ganglion cells were labelled with cholera toxin B subunit-horseradish peroxidase than with wheat germ agglutinin- or isolectin B4-horseradish peroxidase. In the L6-S1 dorsal root ganglia, the majority (81%) of the cholera toxin B subunit-, and almost all of the wheat germ agglutinin- and isolectin B4-immunoreactive cells were RT97-negative (an anti-neurofilament antibody that labels dorsal root ganglion neurons with myelinated fibres). Double labelling with other neuronal markers showed that 71%, 43% and 36% of the cholera toxin B subunit-immunoreactive cells were calcitonin gene-related peptide-, isolectin B4-binding- and substance P-positive, respectively. A few cholera toxin B subunit cells showed galanin-immunoreactivity, but none were somatostatin-, vasoactive intestinal polypeptide-, or neuropeptide Y-immunoreactive or contained fluoride-resistant acid phosphatase. The results show that cholera toxin B subunit-horseradish peroxidase is a more effective retrograde and transganglionic tracer for pelvic primary afferents from the urinary bladder than wheat germ agglutinin-horseradish peroxidase and isolectin B4-horseradish peroxidase, but in contrast to somatic nerves, it is transported mainly by unmyelinated fibres in the visceral afferents.

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

[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.

miRNA Expression Change in Dorsal Root Ganglia After Peripheral Nerve Injury.

PubMed

Chang, Hsueh-Ling; Wang, Hung-Chen; Chunag, Yi-Ta; Chou, Chao-Wen; Lin, I-Ling; Lai, Chung-Sheng; Chang, Lin-Li; Cheng, Kuang-I

2017-02-01

The role of microRNAs (miRNAs) in the regulation of nerve injury-induced neuropathic pain is unclear. The aims of this study were to assess and compare miRNA expression profiles in dorsal root ganglia (DRG) following three different kinds of peripheral nerve injury, including spinal nerve ligation (SNL), dorsal root transection (DRT), and ventral root transection (VRT), in Sprague-Dawley rats. Responses to thermal and mechanical stimuli were measured preoperatively and on postoperative days (PODs) 1, 4, and 7. A miRNA microarray analysis was used to detect the miRNA expression profiles in injured L5 DRG from SNL, DRT, and VRT on POD 7. Validation of miRNA expression was performed by qPCR and in situ hybridization. Rats receiving SNL displayed significantly higher mechanical hypersensitivity, but those receiving DRT developed higher thermal hypersensitivity. The number of miRNAs that were significantly upregulated in L5 DRG was 49 (7.2%), 25 (3.7%), and 146 (21.5%) following SNL, DRT, and VRT, respectively. On the other hand, 35 (5.1%) miRNAs were significantly downregulated in the SNL group, 21 (3.1%) miRNAs in the DRT group, and 41 (6.0%) miRNAs in the VRT group. Of the four miRNAs that were mutually aberrant in all three models, two were significantly upregulated (twofold), miR-21 and miR-31, and two were significantly downregulated, miR-668 and miR-672. Using in situ hybridization, miRNA-21, miRNA-31, miRNA-668, and miRNA-672 were found to localize to neurons in the DRG. Collectively, the mutual abnormal miRNA expression of miR-21, miR-31, miR-668, and miR-677 implied that these miRNAs may be therapeutic targets for alleviating multiple forms of neuropathic pain.

The Different Dynamic Changes of Nerve Growth Factor in the Dorsal Horn and Dorsal Root Ganglion Leads to Hyperalgesia and Allodynia in Diabetic Neuropathic Pain.

PubMed

Gao, Zhifeng; Feng, Yi; Ju, Hui

2017-05-01

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes and more than half of the patients with DPN have self-reported symptoms referring to painful diabetic neuropathy (PDN). Nerve growth factor (NGF) is a key factor for the nervous system, but the role of it in the neuropathic pain of diabetic patients is unclear. This study aimed to investigate the relationship between the dynamic expression of NGF in dorsal horn and dorsal root ganglion (DRG) of diabetic rats and hyperalgesia and allodynia in diabetic neuropathic pain. It also aimed to explore the effects of exogenous mouse NGF (mNGF) on NGF expression in dorsal horn, DRG, and mechanical pain threshold. Animal research study. Experimental research laboratory. The model of diabetes was established by a single intraperitoneal injection of streptozocin (STZ 55 mg/kg). Firstly, the rats were randomly divided into 2 groups: control group (n = 10) and diabetes group (n = 40). The diabetes group contained 4 subgroups: diabetes week 1 group (DM1, n = 10), diabetes week 2 group (DM2, n = 10), diabetes week 4 group (DM4, n = 10), and diabetes week 8 group (DM8, n = 10). Then, the other rats were randomly divided into 2 groups: control group (n = 10) and treatment group (n = 30). The treatment group contained 3 subgroups: saline group (n = 10), low dose mNGF group (mNGF1, n = 10), and high dose mNGF group (mNGF2, n = 10). Mechanical pain threshold was assessed using Von Frey hairs, before the establishment of the diabetes model and 1, 2, 4, and 8 weeks after the establishment. The NGF expression in dorsal horn and DRG was measured by western blot. The mechanical pain threshold decreased one week after the establishment of the diabetes model, which continued for 8 weeks. The NGF expression in the dorsal horn was reduced 2 weeks after diabetes induction and the decreased NGF expression continued for 4 weeks. However, the NGF expression in DRG was reduced one week after diabetes induction and remained at a low level for 8 weeks. Hyperalgesia occurred when the NGF expression in the DRG decreased and further reduction in the NGF expression in the dorsal horn caused concomitant allodynia. The mechanical pain threshold was significantly elevated 2 weeks after mNGF treatment. The course of diabetes should be much longer and there is not a precise analysis of the quantitative relation between the NGF expression in the dorsal horn/DRG and hyperalgesia/allodynia. In diabetic neuropathic pain, the dynamic changes of the NGF expression in dorsal horn and DRG is involved in the development of hyperalgesia and allodynia respectively. Exogenous mNGF may relieve diabetic neuropathic pain by increasing the NGF expression in dorsal horn and DRG.

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.

DREAM regulates BDNF-dependent spinal sensitization

PubMed Central

2010-01-01

Background The transcriptional repressor DREAM (downstream regulatory element antagonist modulator) controls the expression of prodynorphin and has been involved in the modulation of endogenous responses to pain. To investigate the role of DREAM in central mechanisms of pain sensitization, we used a line of transgenic mice (L1) overexpressing a Ca2+- and cAMP-insensitive DREAM mutant in spinal cord and dorsal root ganglia. Results L1 DREAM transgenic mice showed reduced expression in the spinal cord of several genes related to pain, including prodynorphin and BDNF (brain-derived neurotrophic factor) and a state of basal hyperalgesia without change in A-type currents. Peripheral inflammation produced enhancement of spinal reflexes and increased expression of BDNF in wild type but not in DREAM transgenic mice. The enhancement of the spinal reflexes was reproduced in vitro by persistent electrical stimulation of C-fibers in wild type but not in transgenic mice. Exposure to exogenous BDNF produced a long-term enhancement of dorsal root-ventral root responses in transgenic mice. Conclusions Our results indicate that endogenous BDNF is involved in spinal sensitization following inflammation and that blockade of BDNF induction in DREAM transgenic mice underlies the failure to develop spinal sensitization. PMID:21167062

A Retroaortic Left Renal Vein in a Female Cadaver.

PubMed

Fujishima, Yoshiko; Watanabe, Koichi; Tabira, Yoko; Iwanaga, Joe; Odo, Yui; Saga, Tsuyoshi; Tubbs, R Shane; Yamaki, Koh-Ichi

2018-05-21

We encountered a case of retroaortic left renal vein (RLRV) during an anatomical dissection course at our medical school in 2017. The case was a female cadaver who was 88 years old at death. Six roots of the left renal vein (RV) arose from the hilus of the kidney and joined to form one left renal vein, crossed dorsal to the abdominal aorta (AA) at the level of the second lumbar vertebra, and then drained into the inferior vena cava (IVC). Two roots joined at the right renal hilus to become the right RV to then drain into the IVC at the level of the first lumbar vertebral body. The reported frequency of RLRV is approximately 2%. Embryologically, the normal anastomosis of the left and right sub-cardinal veins results in the left RV traveling on the ventral surface of the AA. However, in the case presented here, the left RV traveled on the dorsal side of the AA due to the anastomosis of the left and right supra-cardinal veins and regression of the anastomosis between the left and right sub-cardinal veins. If both the dorsal and ventral anastomoses remain, the left RV travels on the dorsal and ventral sides of the aorta. Some of the clinical problems reported in association with RLRV are hematuria and abdominal pain, and the risk of damaging the RLRV during surgery of the posterior abdominal wall. Venous variants as reported herein should be kept in mind when interpreting imaging of the posterior abdominal wall or performing surgery or other invasive procedures near the RLRV.

Subcutaneous, intrathecal and periaqueductal grey administration of asimadoline and ICI-204448 reduces tactile allodynia in the rat.

PubMed

Caram-Salas, Nadia L; Reyes-García, Gerardo; Bartoszyk, Gerd D; Araiza-Saldaña, Claudia I; Ambriz-Tututi, Mónica; Rocha-González, Héctor I; Arreola-Espino, Rosaura; Cruz, Silvia L; Granados-Soto, Vinicio

2007-11-14

The purpose of this study was to assess the possible antiallodynic effect of asimadoline ([N-methyl-N-[1S)-1-phenyl)-2-(13S))-3-hydroxypyrrolidine-1-yl)-ethyl]-2,2-diphenylacetamide HCl]) and ICI-20448 ([2-[3-(1-(3,4-Dichlorophenyl-N-methylacetamido)-2-pyrrolidinoethyl)-phenoxy]acetic acid HCl]), two peripheral selective kappa opioid receptor agonists, after subcutaneous, spinal and periaqueductal grey administration to neuropathic rats. Twelve days after spinal nerve ligation tactile allodynia was observed, along with an increase in kappa opioid receptor mRNA expression in dorsal root ganglion and dorsal horn spinal cord. A non-significant increase in periaqueductal grey was also seen. Subcutaneous (s.c.) administration of asimadoline and ICI-204448 (1-30 mg/kg) dose-dependently reduced tactile allodynia. This effect was partially blocked by s.c., but not intrathecal, naloxone. Moreover, intrathecal administration of asimadoline or ICI-204448 (1-30 mug) reduced tactile allodynia in a dose-dependent manner and this effect was completely blocked by intrathecal naloxone. Microinjection of both kappa opioid receptor agonists (3-30 mug) into periaqueductal grey also produced a naloxone-sensitive antiallodynic effect in rats. Our results indicate that systemic, intrathecal and periaqueductal grey administration of asimadoline and ICI-204448 reduces tactile allodynia. This effect may be a consequence of an increase in kappa opioid receptor mRNA expression in dorsal root ganglion, dorsal horn spinal cord and, to some extent, in periaqueductal grey. Finally, our data suggest that these drugs could be useful to treat neuropathic pain in human beings.

Epinephrine administered with lidocaine solution does not worsen intrathecal lidocaine neurotoxicity in rats.

PubMed

Komatsu, Toshiaki; Takenami, Tamie; Nara, Yoshihiro; Yagishita, Saburo; Kurashige, Chie; Okamoto, Hirotsugu; Yago, Kazuo

2013-01-01

Epinephrine can potentially worsen the neurotoxic effects of local anesthetics when used for spinal or epidural anesthesia. The vasoconstrictive property of epinephrine reduces dural blood flow, which in turn reduces the clearance of local anesthetics from the subarachnoid space. This study examined the histological and neurofunctional effects of intrathecally administered lidocaine combined with epinephrine in rats. Sixty-two rats were divided into 9 treatment groups: 5% or 7.5% lidocaine in 10% glucose solution with or without 0.1 or 0.5 mg/mL epinephrine, or epinephrine alone at 0.1 or 0.5 mg/mL in 10% glucose, or 10% glucose alone. Hind-limb motor function was evaluated immediately after drug injection by walking behavior. Sensory function was assessed by the response to radiant heat stimulation at just before and 1 week after the injection. Seven days after the injection, L3 spinal cord with anterior and posterior roots, the dorsal ganglion, and cauda equina were harvested and examined histologically. Histological lesions were limited to the posterior root just at entry into the spinal cord in rats injected with 7.5% lidocaine, with and without epinephrine. No histological abnormalities were noted in other areas or other groups. There was no significant change in sensory threshold in all groups. Significantly, prolongation of gait recovery time was noted in 5% and 7.5% lidocaine with epinephrine groups compared with 5% or 7.5% lidocaine alone. Intrathecal epinephrine prolonged the action of intrathecal lidocaine but did not worsen lidocaine-induced histological damage and functional impairment.

Inflammation in the Pathogenesis of Lyme Neuroborreliosis

PubMed Central

Ramesh, Geeta; Didier, Peter J.; England, John D.; Santana-Gould, Lenay; Doyle-Meyers, Lara A.; Martin, Dale S.; Jacobs, Mary B.; Philipp, Mario T.

2016-01-01

Lyme neuroborreliosis, caused by the spirochete Borrelia burgdorferi, affects both peripheral and central nervous systems. We assessed a causal role for inflammation in Lyme neuroborreliosis pathogenesis by evaluating the induced inflammatory changes in the central nervous system, spinal nerves, and dorsal root ganglia (DRG) of rhesus macaques that were inoculated intrathecally with live B. burgdorferi and either treated with dexamethasone or meloxicam (anti-inflammatory drugs) or left untreated. ELISA of cerebrospinal fluid showed significantly elevated levels of IL-6, IL-8, chemokine ligand 2, and CXCL13 and pleocytosis in all infected animals, except dexamethasone-treated animals. Cerebrospinal fluid and central nervous system tissues of infected animals were culture positive for B. burgdorferi regardless of treatment. B. burgdorferi antigen was detected in the DRG and dorsal roots by immunofluorescence staining and confocal microscopy. Histopathology revealed leptomeningitis, vasculitis, and focal inflammation in the central nervous system; necrotizing focal myelitis in the cervical spinal cord; radiculitis; neuritis and demyelination in the spinal roots; and inflammation with neurodegeneration in the DRG that was concomitant with significant neuronal and satellite glial cell apoptosis. These changes were absent in the dexamethasone-treated animals. Electromyography revealed persistent abnormalities in F-wave chronodispersion in nerve roots of a few infected animals; which were absent in dexamethasone-treated animals. These results suggest that inflammation has a causal role in the pathogenesis of acute Lyme neuroborreliosis. PMID:25892509

Inhibitory effects of eugenol on putative nociceptive response in spinal cord preparation isolated from neonatal rats.

PubMed

Yagura, Saki; Onimaru, Hiroshi; Kanzaki, Koji; Izumizaki, Masahiko

2018-06-01

Eugenol is contained in several plants including clove and is thought to exert an analgesic effect. It has been suggested that the slow ventral root potential induced by ipsilateral dorsal root stimulation in the isolated (typically lumbar) spinal cord of newborn rats reflects the nociceptive response, and this in vitro experimental model is useful to assess the actions of analgesics. To further elucidate neuronal mechanisms of eugenol-induced analgesia, we examined the effects of extracellularly applied eugenol on the nociceptive spinal reflex response. To evaluate the effects of eugenol on putative nociceptive responses, the ipsilateral fifth lumbar (L5) dorsal root was stimulated using a glass suction electrode, and the induced reflex responses were recorded from the L5 and twelfth thoracic (Th12) ventral roots in spinal cord preparations (Th10-L5) from newborn rats (postnatal day 0-3). We found that eugenol (0.25-1.0 mM) caused dose-dependent attenuation of the reflex response and also depressed spontaneous ventral root activity. We also found that the slow ventral root potential was further divided into two components: initial and late components. A lower concentration of eugenol selectively depressed the late component. The inhibitory effects by 1.0 mM eugenol were not reversed by 10 µM capsazepine (TRPV1 antagonist) or 40 µM HC-030031 (TRPA1 antagonist). The depressive effect of eugenol on the reflex response was also confirmed by optical recordings using voltage-sensitive dye. Our report provides additional evidence on the basic neuronal mechanisms of eugenol to support its clinical use as a potential analgesic treatment.

Somatostatin and its 2A receptor in dorsal root ganglia and dorsal horn of mouse and human: expression, trafficking and possible role in pain

PubMed Central

2014-01-01

Background Somatostatin (SST) and some of its receptor subtypes have been implicated in pain signaling at the spinal level. In this study we have investigated the role of SST and its sst2A receptor (sst2A) in dorsal root ganglia (DRGs) and spinal cord. Results SST and sst2A protein and sst2 transcript were found in both mouse and human DRGs, sst2A-immunoreactive (IR) cell bodies and processes in lamina II in mouse and human spinal dorsal horn, and sst2A-IR nerve terminals in mouse skin. The receptor protein was associated with the cell membrane. Following peripheral nerve injury sst2A-like immunoreactivity (LI) was decreased, and SST-LI increased in DRGs. sst2A-LI accumulated on the proximal and, more strongly, on the distal side of a sciatic nerve ligation. Fluorescence-labeled SST administered to a hind paw was internalized and retrogradely transported, indicating that a SST-sst2A complex may represent a retrograde signal. Internalization of sst2A was seen in DRG neurons after systemic treatment with the sst2 agonist octreotide (Oct), and in dorsal horn and DRG neurons after intrathecal administration. Some DRG neurons co-expressed sst2A and the neuropeptide Y Y1 receptor on the cell membrane, and systemic Oct caused co-internalization, hypothetically a sign of receptor heterodimerization. Oct treatment attenuated the reduction of pain threshold in a neuropathic pain model, in parallel suppressing the activation of p38 MAPK in the DRGs Conclusions The findings highlight a significant and complex role of the SST system in pain signaling. The fact that the sst2A system is found also in human DRGs and spinal cord, suggests that sst2A may represent a potential pharmacologic target for treatment of neuropathic pain. PMID:24521084

A new class of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in plant parasitic cyst nematodes.

PubMed

Tytgat, Tom; Vanholme, Bartel; De Meutter, Jan; Claeys, Myriam; Couvreur, Marjolein; Vanhoutte, Isabelle; Gheysen, Greetje; Van Criekinge, Wim; Borgonie, Gaetan; Coomans, August; Gheysen, Godelieve

2004-08-01

By performing cDNA AFLP on pre- and early parasitic juveniles, we identified genes encoding a novel type of ubiquitin extension proteins secreted by the dorsal pharyngeal gland in the cyst nematode Heterodera schachtii. The proteins consist of three domains, a signal peptide for secretion, a mono-ubiquitin domain, and a short C-terminal positively charged domain. A gfp-fusion of this protein is targeted to the nucleolus in tobacco BY-2 cells. We hypothesize that the C-terminal peptide might have a regulatory function during syncytium formation in plant roots.

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.

Polyunsaturated fatty acids are potent openers of human M-channels expressed in Xenopus laevis oocytes.

PubMed

Liin, S I; Karlsson, U; Bentzen, B H; Schmitt, N; Elinder, F

2016-09-01

Polyunsaturated fatty acids have been reported to reduce neuronal excitability, in part by promoting inactivation of voltage-gated sodium and calcium channels. Effects on neuronal potassium channels are less explored and experimental data ambiguous. The aim of this study was to investigate anti-excitable effects of polyunsaturated fatty acids on the neuronal M-channel, important for setting the resting membrane potential in hippocampal and dorsal root ganglion neurones. Effects of fatty acids and fatty acid analogues on mouse dorsal root ganglion neurones and on the human KV 7.2/3 channel expressed in Xenopus laevis oocytes were studied using electrophysiology. Extracellular application of physiologically relevant concentrations of the polyunsaturated fatty acid docosahexaenoic acid hyperpolarized the resting membrane potential (-2.4 mV by 30 μm) and increased the threshold current to evoke action potentials in dorsal root ganglion neurones. The polyunsaturated fatty acids docosahexaenoic acid, α-linolenic acid and eicosapentaenoic acid facilitated opening of the human M-channel, comprised of the heteromeric human KV 7.2/3 channel expressed in Xenopus oocytes, by shifting the conductance-vs.-voltage curve towards more negative voltages (by -7.4 to -11.3 mV by 70 μm). Uncharged docosahexaenoic acid methyl ester and monounsaturated oleic acid did not facilitate opening of the human KV 7.2/3 channel. These findings suggest that circulating polyunsaturated fatty acids, with a minimum requirement of multiple double bonds and a charged carboxyl group, dampen excitability by opening neuronal M-channels. Collectively, our data bring light to the molecular targets of polyunsaturated fatty acids and thus a possible mechanism by which polyunsaturated fatty acids reduce neuronal excitability. © 2016 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Cannabinoid CB1 receptor facilitation of substance P release in the rat spinal cord, measured as neurokinin 1 receptor internalization

PubMed Central

Zhang, Guohua; Chen, Wenling; Lao, Lijun; Marvizón, Juan Carlos G.

2010-01-01

The contribution of CB1 receptors in the spinal cord to cannabinoid analgesia is still unclear. The objective of this study was to investigate the effect of CB1 receptors on substance P release from primary afferent terminals in the spinal cord. Substance P release was measured as NK1 receptor internalization in lamina I neurons. It was induced in spinal cord slices by dorsal root stimulation and in live rats by a noxious stimulus. In spinal cord slices, the CB1 receptor antagonists AM251, AM281 and rimonabant partially but potently inhibited NK1 receptor internalization induced by electrical stimulation of the dorsal root. This was due to an inhibition of substance P release and not of NK1 receptor internalization itself, because AM251 and AM281 did not inhibit NK1 receptor internalization induced by exogenous substance P. The CB1 receptor agonist ACEA increased NK1 receptor internalization evoked by dorsal root stimulation. The effects of AM251 and ACEA cancelled each other. In vivo, AM251 injected intrathecally decreased NK1 receptor internalization in spinal segments L5 and L6 induced by noxious hind paw clamp. Intrathecal AM251 also produced analgesia to radiant heat stimulation of the paw. The inhibition by AM251 of NK1 receptor internalization was reversed by antagonists of μ-opioid and GABAB receptors. This indicates that CB1 receptors facilitate substance P release by inhibiting the release of GABA and opioids next to primary afferent terminals, producing disinhibition. This results in a pronociceptive effect of CB1 receptors in the spinal cord. PMID:20074214

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

Transverse tripolar spinal cord stimulation: theoretical performance of a dual channel system.

PubMed

Struijk, J J; Holsheimer, J

1996-07-01

A new approach to spinal cord stimulation is presented, by which several serious problems of conventional methods can be solved. A transverse tripolar electrode with a dual-channel voltage stimulator is evaluated theoretically by means of a volume conductor model, combined with nerve fibre models. The simulations predict that a high degree of freedom in the control of activation of dorsal spinal pathways may be obtained with the described system. This implies an easier control of paraesthesia coverage of skin areas and the possibility to correct undesired paraesthesia patterns, caused by lead migration, tissue growth, or anatomical asymmetries, for example, without surgical intervention. It will also be possible to preferentially activate either dorsal column or dorsal root fibres, which has some important clinical advantages. Compared to conventional stimulation systems, the new system has a relatively high current drain.

Atrial development in the human heart: an immunohistochemical study with emphasis on the role of mesenchymal tissues

NASA Technical Reports Server (NTRS)

Wessels, A.; Anderson, R. H.; Markwald, R. R.; Webb, S.; Brown, N. A.; Viragh, S.; Moorman, A. F.; Lamers, W. H.

2000-01-01

The development of the atrial chambers in the human heart was investigated immunohistochemically using a set of previously described antibodies. This set included the monoclonal antibody 249-9G9, which enabled us to discriminate the endocardial cushion-derived mesenchymal tissues from those derived from extracardiac splanchnic mesoderm, and a monoclonal antibody recognizing the B isoform of creatine kinase, which allowed us to distinguish the right atrial myocardium from the left. The expression patterns obtained with these antibodies, combined with additional histological information derived from the serial sections, permitted us to describe in detail the morphogenetic events involved in the development of the primary atrial septum (septum primum) and the pulmonary vein in human embryos from Carnegie stage 14 onward. The level of expression of creatine kinase B (CK-B) was found to be consistently higher in the left atrial myocardium than in the right, with a sharp boundary between high and low expression located between the primary septum and the left venous valve indicating that the primary septum is part of the left atrial gene-expression domain. This expression pattern of CK-B is reminiscent of that of the homeobox gene Pitx2, which has recently been shown to be important for atrial septation in the mouse. This study also demonstrates a poorly appreciated role of the dorsal mesocardium in cardiac development. From the earliest stage investigated onward, the mesenchyme of the dorsal mesocardium protrudes into the dorsal wall of the primary atrial segment. This dorsal mesenchymal protrusion is continuous with a mesenchymal cap on the leading edge of the primary atrial septum. Neither the mesenchymal tissues of the dorsal protrusion nor the mesenchymal cap on the edge of the primary septum expressed the endocardial tissue antigen recognized by 249-9G9 at any of the stages investigated. The developing pulmonary vein uses the dorsal mesocardium as a conduit to reach the primary atrial segment. Initially, the pulmonary pit, which will becomes the portal of entry for the pulmonary vein, is located along the midline, flanked by two myocardial ridges. As development progresses, tissue remodeling results in the incorporation of the portal of entry of the pulmonary vein in left atrial myocardium, which is recognized because of its high level of creatine. Closure of the primary atrial foramen by the primary atrial septum occurs as a consequence of the fusion of these mesenchymal structures. Copyright 2000 Wiley-Liss, Inc.

Teaching Materials and Methods.

ERIC Educational Resources Information Center

Physiologist, 1987

1987-01-01

Contains abstracts of presented papers which deal with teaching materials and methods in physiology. Includes papers on preconceptual notions in physiology, somatosensory activity recorded in the dorsal root ganglion of the bull frog, and the use of the Apple Macintosh microcomputer in teaching human anatomy and physiology. (TW)

[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.

The experimental study of genetic engineering human neural stem cells mediated by lentivirus to express multigene.

PubMed

Cai, Pei-qiang; Tang, Xun; Lin, Yue-qiu; Martin, Oudega; Sun, Guang-yun; Xu, Lin; Yang, Yun-kang; Zhou, Tian-hua

2006-02-01

To explore the feasibility to construct genetic engineering human neural stem cells (hNSCs) mediated by lentivirus to express multigene in order to provide a graft source for further studies of spinal cord injury (SCI). Human neural stem cells from the brain cortex of human abortus were isolated and cultured, then gene was modified by lentivirus to express both green fluorescence protein (GFP) and rat neurotrophin-3 (NT-3); the transgenic expression was detected by the methods of fluorescence microscope, dorsal root ganglion of fetal rats and slot blot. Genetic engineering hNSCs were successfully constructed. All of the genetic engineering hNSCs which expressed bright green fluorescence were observed under the fluorescence microscope. The conditioned medium of transgenic hNSCs could induce neurite flourishing outgrowth from dorsal root ganglion (DRG). The genetic engineering hNSCs expressed high level NT-3 which could be detected by using slot blot. Genetic engineering hNSCs mediated by lentivirus can be constructed to express multigene successfully.

HSV-mediated gene transfer of vascular endothelial growth factor to dorsal root ganglia prevents diabetic neuropathy

PubMed Central

Chattopadhyay, M; Krisky, D; Wolfe, D; Glorioso, JC; Mata, M; Fink, DJ

2005-01-01

We examined the utility of herpes simplex virus (HSV) vector-mediated gene transfer of vascular endothelial growth factor (VEGF) in a mouse model of diabetic neuropathy. A replication-incompetent HSV vector with VEGF under the control of the HSV ICP0 promoter (vector T0VEGF) was constructed. T0VEGF expressed and released VEGF from primary dorsal root ganglion (DRG) neurons in vitro, and following subcutaneous inoculation in the foot, expressed VEGF in DRG and nerve in vivo. At 2 weeks after induction of diabetes, subcutaneous inoculation of T0VEGF prevented the reduction in sensory nerve amplitude characteristic of diabetic neuropathy measured 4 weeks later, preserved autonomic function measured by pilocarpine-induced sweating, and prevented the loss of nerve fibers in the skin and reduction of neuropeptide calcitonin gene-related peptide and substance P in DRG neurons of the diabetic mice. HSV-mediated transfer of VEGF to DRG may prove useful in treatment of diabetic neuropathy. PMID:15843809

Evaluation of Cisplatin Neurotoxicity in Cultured Rat Dorsal Root Ganglia via Cytosolic Calcium Accumulation

PubMed Central

Erol, Kevser; Yiğitaslan, Semra; Ünel, Çiğdem; Kaygısız, Bilgin; Yıldırım, Engin

2016-01-01

Background: Calcium homeostasis is considered to be important in antineoplastic as well as in neurotoxic adverse effects of cisplatin. Aims: This study aimed to investigate the role of Ca2+ in cisplatin neurotoxicity in cultured rat dorsal root ganglia (DRG) cells. Study Design: Cell culture study. Methods: DRG cells prepared from 1-day old Sprague-Dawley rats were used to determine the role of Ca2+ in the cisplatin (10–600 μM) neurotoxicity. The cells were incubated with cisplatin plus nimodipine (1–3 μM), dizocilpine (MK-801) (1–3 μM) or thapsigargin (100–300 nM). Toxicity of cisplatinon DRG cells was determined by the MTT assay. Results: The neurotoxicity of cisplatin was significant when used in high concentrations (100–600 μM). Nimodipine (1 μM) but not MK-801 or thapsigargin prevented the neurotoxic effects of 200 μM of cisplatin. Conclusion: Voltage-dependent calcium channels may play a role in cisplatin neurotoxicity. PMID:27403382

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.

Staphylococcal leukotoxins trigger free intracellular Ca2+ rise in neurones, signalling through acidic stores and activation of store-operated channels

PubMed Central

Jover, Emmanuel; Tawk, Mira Y; Laventie, Benoît-Joseph; Poulain, Bernard; Prévost, Gilles

2013-01-01

Headache, muscle aches and chest pain of mild to medium intensity are among the most common clinical symptoms in moderate Staphylococcus aureus infections, with severe infections usually associated with worsening pain symptoms. These nociceptive responses of the body raise the question of how bacterial infection impinges on the nervous system. Does S. aureus, or its released virulence factors, act directly on neurones? To address this issue, we evaluated the potential effects on neurones of certain bi-component leukotoxins, which are virulent factors released by the bacterium. The activity of four different leukotoxins was verified by measuring the release of glutamate from rat cerebellar granular neurones. The bi-component γ-haemolysin HlgC/HlgB was the most potent leukotoxin, initiating transient rises in intracellular Ca2+ concentration in cerebellar neurones and in primary sensory neurones from dorsal root ganglia, as probed with the Fura-2 Ca2+ indicator dye. Using pharmacological antagonists of receptors and Ca2+ channels, the variations in intracellular Ca2+ concentration were found independent of the activation of voltage-operatedCa2+ channels or glutamate receptors. Drugs targeting Sarco-Endoplasmic Reticulum Ca2+-ATPase (SERCA) or H+-ATPase and antagonists of the store-operated Ca2+ entry complex blunted, or significantly reduced, the leukotoxin-induced elevation in intracellular Ca2+. Moreover, activation of the ADP-ribosyl cyclase CD38 was also required to initiate the release of Ca2+ from acidic stores. These findings suggest that, prior to forming a pore at the plasma membrane, leukotoxin HlgC/HlgB triggers a multistep process which initiates the release of Ca2+ from lysosomes, modifies the steady-state level of reticular Ca2+ stores and finally activates the Store-Operated Calcium Entry complex. PMID:23152983

Staphylococcal leukotoxins trigger free intracellular Ca(2+) rise in neurones, signalling through acidic stores and activation of store-operated channels.

PubMed

Jover, Emmanuel; Tawk, Mira Y; Laventie, Benoît-Joseph; Poulain, Bernard; Prévost, Gilles

2013-05-01

Headache, muscle aches and chest pain of mild to medium intensity are among the most common clinical symptoms in moderate Staphylococcus aureus infections, with severe infections usually associated with worsening pain symptoms. These nociceptive responses of the body raise the question of how bacterial infection impinges on the nervous system. Does S. aureus, or its released virulence factors, act directly on neurones? To address this issue, we evaluated the potential effects on neurones of certain bi-component leukotoxins, which are virulent factors released by the bacterium. The activity of four different leukotoxins was verified by measuring the release of glutamate from rat cerebellar granular neurones. The bi-component γ-haemolysin HlgC/HlgB was the most potent leukotoxin, initiating transient rises in intracellular Ca(2+) concentration in cerebellar neurones and in primary sensory neurones from dorsal root ganglia, as probed with the Fura-2 Ca(2+) indicator dye. Using pharmacological antagonists of receptors and Ca(2+) channels, the variations in intracellular Ca(2+) concentration were found independent of the activation of voltage-operated Ca(2+) channels or glutamate receptors. Drugs targeting Sarco-Endoplasmic Reticulum Ca(2+)-ATPase (SERCA) or H(+)-ATPase and antagonists of the store-operated Ca(2+) entry complex blunted, or significantly reduced, the leukotoxin-induced elevation in intracellular Ca(2+). Moreover, activation of the ADP-ribosyl cyclase CD38 was also required to initiate the release of Ca(2+) from acidic stores. These findings suggest that, prior to forming a pore at the plasma membrane, leukotoxin HlgC/HlgB triggers a multistep process which initiates the release of Ca(2+) from lysosomes, modifies the steady-state level of reticular Ca(2+) stores and finally activates the Store-Operated Calcium Entry complex. © 2012 Blackwell Publishing Ltd.

[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.

Evidence of the Primary Afferent Tracts Undergoing Neurodegeneration in Horses With Equine Degenerative Myeloencephalopathy Based on Calretinin Immunohistochemical Localization.

PubMed

Finno, C J; Valberg, S J; Shivers, J; D'Almeida, E; Armién, A G

2016-01-01

Equine degenerative myeloencephalopathy (EDM) is characterized by a symmetric general proprioceptive ataxia in young horses, and is likely underdiagnosed for 2 reasons: first, clinical signs overlap those of cervical vertebral compressive myelopathy; second, histologic lesions--including axonal spheroids in specific tracts of the somatosensory and motor systems--may be subtle. The purpose of this study was (1) to utilize immunohistochemical (IHC) markers to trace axons in the spinocuneocerebellar, dorsal column-medial lemniscal, and dorsospinocerebellar tracts in healthy horses and (2) to determine the IHC staining characteristics of the neurons and degenerated axons along the somatosensory tracts in EDM-affected horses. Examination of brain, spinal cord, and nerves was performed on 2 age-matched control horses, 3 EDM-affected horses, and 2 age-matched disease-control horses via IHC for calbindin, vesicular glutamate transporter 2, parvalbumin, calretinin, glutamic acid decarboxylase, and glial fibrillary acidic protein. Primary afferent axons of the spinocuneocerebellar, dorsal column-medial lemniscal, and dorsospinocerebellar tracts were successfully traced with calretinin. Calretinin-positive cell bodies were identified in a subset of neurons in the dorsal root ganglia, suggesting that calretinin IHC could be used to trace axonal projections from these cell bodies. Calretinin-immunoreactive spheroids were present in EDM-affected horses within the nuclei cuneatus medialis, cuneatus lateralis, and thoracicus. Neurons within those nuclei were calretinin negative. Cell bodies of degenerated axons in EDM-affected horses are likely located in the dorsal root ganglia. These findings support the role of sensory axonal degeneration in the pathogenesis of EDM and provide a method to highlight tracts with axonal spheroids to aid in the diagnosis of this neurodegenerative disease. © The Author(s) 2015.

Effects of combined electrical stimulation of the dorsal column and dorsal roots on wide-dynamic range neuronal activity in nerve-injured rats

PubMed Central

Yang, Fei; Zhang, Tong; Tiwari, Vinod; Shu, Bin; Zhang, Chen; Wang, Yun; Vera-Portocarrero, Louis P.; Raja, Srinivasa N.; Guan, Yun

2015-01-01

Objectives Electrical stimulation at the dorsal column (DC) and dorsal root (DR) may inhibit spinal wide-dynamic-range (WDR) neuronal activity in nerve-injured rats. The objective of this study was to determine if applying electrical conditioning stimulation (CS) at both sites provides additive or synergistic benefits. Materials and Methods By conducting in vivo extracellular recordings of WDR neurons in rats that had undergone L5 spinal nerve ligation, we tested whether combining 50 Hz CS at the two sites in either a concurrent (2.5 minutes) or alternate (5 minutes) pattern inhibits WDR neuronal activity better than CS at DC alone (5 minutes). The intensities of CS were determined by recording antidromic compound action potentials to graded stimulation at the DC and DR. We measured the current thresholds that resulted in the first detectable Aα/β waveform (Ab0) and the peak Aα/β waveform (Ab1) to select CS intensity at each site. The same number of electrical pulses and amount of current were delivered in different patterns to allow comparison. Results At a moderate intensity of 50%(Ab0+Ab1), different patterns of CS all attenuated the C-component of WDR neurons in response to graded intracutaneous electrical stimuli (0.1-10 mA, 2 ms), and inhibited windup in response to repetitive noxious stimuli (0.5 Hz). However, the inhibitory effects did not differ significantly between different patterns. At the lower intensity (Ab0), no CS inhibited WDR neurons. Conclusions These findings suggest that combined stimulation of DC and DR may not be superior to DC stimulation alone for inhibition of WDR neurons. PMID:26307526

μ-Opioid receptor inhibition of substance P release from primary afferents disappears in neuropathic pain but not inflammatory pain

PubMed Central

Chen, Wenling; McRoberts, James A.; Marvizón, Juan Carlos G.

2014-01-01

Opiate analgesia in the spinal cord is impaired during neuropathic pain. We hypothesized that this is caused by a decrease in μ-opioid receptor inhibition of neurotransmitter release from primary afferents. To investigate this possibility, we measured substance P release in the spinal dorsal horn as neurokinin 1 receptor (NK1R) internalization in rats with chronic constriction injury (CCI) of the sciatic nerve. Noxious stimulation of the paw with CCI produced inconsistent NK1R internalization, suggesting that transmission of nociceptive signals by the injured nerve was variably impaired after CCI. This idea was supported by the fact that CCI produced only small changes in the ability of exogenous substance P to induce NK1R internalization or in the release of substance P evoked centrally from site of nerve injury. In subsequent experiments, NK1R internalization was induced in spinal cord slices by stimulating the dorsal root ipsilateral to CCI. We observed a complete loss of the inhibition of substance P release by the μ-opioid receptor agonist [D-Ala2, NMe-Phe4, Gly-ol5]-enkephalin (DAMGO) in CCI rats but not in sham-operated rats. In contrast, DAMGO still inhibited substance P release after inflammation of the hind paw with complete Freund’s adjuvant and in naïve rats. This loss of inhibition was not due to μ-opioid receptor downregulation in primary afferents, because their colocalization with substance P was unchanged, both in dorsal root ganglion neurons and primary afferent fibers in the dorsal horn. In conclusion, nerve injury eliminates the inhibition of substance P release by μ-opioid receptors, probably by hindering their signaling mechanisms. PMID:24583035

μ-Opioid receptor inhibition of substance P release from primary afferents disappears in neuropathic pain but not inflammatory pain.

PubMed

Chen, W; McRoberts, J A; Marvizón, J C G

2014-05-16

Opiate analgesia in the spinal cord is impaired during neuropathic pain. We hypothesized that this is caused by a decrease in μ-opioid receptor inhibition of neurotransmitter release from primary afferents. To investigate this possibility, we measured substance P release in the spinal dorsal horn as neurokinin 1 receptor (NK1R) internalization in rats with chronic constriction injury (CCI) of the sciatic nerve. Noxious stimulation of the paw with CCI produced inconsistent NK1R internalization, suggesting that transmission of nociceptive signals by the injured nerve was variably impaired after CCI. This idea was supported by the fact that CCI produced only small changes in the ability of exogenous substance P to induce NK1R internalization or in the release of substance P evoked centrally from site of nerve injury. In subsequent experiments, NK1R internalization was induced in spinal cord slices by stimulating the dorsal root ipsilateral to CCI. We observed a complete loss of the inhibition of substance P release by the μ-opioid receptor agonist [D-Ala(2), NMe-Phe(4), Gly-ol(5)]-enkephalin (DAMGO) in CCI rats but not in sham-operated rats. In contrast, DAMGO still inhibited substance P release after inflammation of the hind paw with complete Freund's adjuvant and in naïve rats. This loss of inhibition was not due to μ-opioid receptor downregulation in primary afferents, because their colocalization with substance P was unchanged, both in dorsal root ganglion neurons and primary afferent fibers in the dorsal horn. In conclusion, nerve injury eliminates the inhibition of substance P release by μ-opioid receptors, probably by hindering their signaling mechanisms. Published by Elsevier Ltd.

Cervical extraforaminal ligaments: an anatomical study.

PubMed

Arslan, Mehmet; Açar, Halil İbrahim; Cömert, Ayhan

2017-12-01

The purpose of this study was to elucidate the anatomy and clinical importance of extraforaminal ligaments in the cervical region. This study was performed on eight embalmed cadavers. The existence and types of extraforaminal ligaments were identified. The morphology, quantity, origin, insertion, and orientation of the extraforaminal ligaments in the cervical region were observed. Extraforaminal ligaments could be divided into two types: transforaminal ligaments and radiating ligaments. It was observed that during their course, transforaminal ligaments cross the intervertebral foramen ventrally. They usually originate from the anteroinferior margin of the anterior tubercle of the cranial transverse process and insert into the superior margin of the anterior tubercle of the caudal transverse process. The dorsal aspect of the transforaminal ligaments adhere loosely to the spinal nerve sheath. The length, width and thickness of these ligaments increased from the cranial to the caudal direction. A single intervertebral foramen contained at least one transforaminal ligament. A total of 98 ligaments in 96 intervertebral foramina were found. The spinal nerves were extraforaminally attached to neighboring anterior and posterior tubercle of the cervical transverse process by the radiating ligaments. The radiating ligaments consisted of the ventral superior, ventral, ventral inferior, dorsal superior and dorsal inferior radiating ligaments. Radiating ligaments originated from the adjacent transverse processes and inserted into the nerve root sheath. The spinal nerve was held like the hub of a wheel by a series of radiating ligaments. The dorsal ligaments were the thickest. From C2-3 to C6-7 at the cervical spine, radiating ligaments were observed. They developed particularly at the level of the C5-C6 intervertebral foramen. This anatomic study may provide a better understanding of the relationship of the extraforaminal ligaments to the cervical nerve root.

Evidence of the Primary Afferent Tracts Undergoing Neurodegeneration in Horses With Equine Degenerative Myeloencephalopathy Based on Calretinin Immunohistochemical Localization

PubMed Central

Finno, C. J.; Valberg, S. J.; Shivers, J.; D’Almeida, E.; Armién, A. G.

2016-01-01

Equine degenerative myeloencephalopathy (EDM) is characterized by a symmetric general proprioceptive ataxia in young horses, and is likely underdiagnosed for 2 reasons: first, clinical signs overlap those of cervical vertebral compressive myelopathy; second, histologic lesions—including axonal spheroids in specific tracts of the somatosensory and motor systems—may be subtle. The purpose of this study was (1) to utilize immunohistochemical (IHC) markers to trace axons in the spinocuneocerebellar, dorsal column–medial lemniscal, and dorsospinocerebellar tracts in healthy horses and (2) to determine the IHC staining characteristics of the neurons and degenerated axons along the somatosensory tracts in EDM-affected horses. Examination of brain, spinal cord, and nerves was performed on 2 age-matched control horses, 3 EDM-affected horses, and 2 age-matched disease-control horses via IHC for calbindin, vesicular glutamate transporter 2, parvalbumin, calretinin, glutamic acid decarboxylase, and glial fibrillary acidic protein. Primary afferent axons of the spinocuneocerebellar, dorsal column–medial lemniscal, and dorsospinocerebellar tracts were successfully traced with calretinin. Calretinin-positive cell bodies were identified in a subset of neurons in the dorsal root ganglia, suggesting that calretinin IHC could be used to trace axonal projections from these cell bodies. Calretinin-immunoreactive spheroids were present in EDM-affected horses within the nuclei cuneatus medialis, cuneatus lateralis, and thoracicus. Neurons within those nuclei were calretinin negative. Cell bodies of degenerated axons in EDM-affected horses are likely located in the dorsal root ganglia. These findings support the role of sensory axonal degeneration in the pathogenesis of EDM and provide a method to highlight tracts with axonal spheroids to aid in the diagnosis of this neurodegenerative disease. PMID:26253880

Comparative Developmental Anatomy of the Root in Three Species of Cladopus (Podostemaceae)

PubMed Central

KOI, SATOSHI; KATO, MASAHIRO

2003-01-01

Root meristem structure and root branching in three species of Cladopus were investigated from developmental and anatomical perspectives. Cladopus fukiensis has a compressed bell‐shaped meristem at the apex of a compressed subcylindrical root, while C. javanicus and perhaps C. nymanii, with a ribbon‐like root, have a half lozenge‐shaped (⊂ as seen from above) meristem composed of an apical meristem of cubic cells and a marginal meristem of rectangular cells. The dorsiventrality of the meristem results in root dorsiventrality, and a marginal meristem contributes to the broadening of the root. Comparisons of meristem structure and root morphology suggest that the ribbon‐like root of, e.g. C. javanicus, evolved towards the foliose root of Hydrobryum, sister to the genus Cladopus, by loss of an indeterminate apical meristem. The lateral root of C. javanicus initiates within the meristem of a parent root. The dorsal dermal layer and inner cells of the lateral‐root meristem appear endogenously under the dermal layer of the parent root, while the ventral layer is derived exogenously from a ventral dermal layer continuous with the parent‐root meristem. This mosaic pattern of exogenous and endogenous root formation differs from the truly exogenous formation seen in Hydrobryum and Zeylanidium. The dorsiventral mosaic origin of the root meristem may account for root cap asymmetry. PMID:12770848

Rooting depth and root depth distribution of Trifolium repens × T. uniflorum interspecific hybrids.

PubMed

Nichols, S N; Hofmann, R W; Williams, W M; van Koten, C

2016-05-20

Traits related to root depth distribution were examined in Trifolium repens × T. uniflorum backcross 1 (BC 1 ) hybrids to determine whether root characteristics of white clover could be improved by interspecific hybridization. Two white clover cultivars, two T. uniflorum accessions and two BC 1 populations were grown in 1 -m deep tubes of sand culture. Maximum rooting depth and root mass distribution were measured at four harvests over time, and root distribution data were fitted with a regression model to provide measures of root system shape. Morphological traits were measured at two depths at harvest 3. Root system shape of the hybrids was more similar to T. uniflorum than to white clover. The hybrids and T. uniflorum had a higher rate of decrease in root mass with depth than white clover, which would result in higher proportions of root mass in the upper profile. Percentage total root mass at 100-200 mm depth was higher for T. uniflorum than white clover, and for Crusader BC 1 than 'Crusader'. Roots of the hybrids and T. uniflorum also penetrated deeper than those of white clover. T. uniflorum had thicker roots at 50-100 mm deep than the other entries, and more of its fine root mass at 400-500 mm. The hybrids and white clover had more of their fine root mass higher in the profile. Consequently, T. uniflorum had a higher root length density at 400-500 mm than most entries, and a smaller decrease in root length density with depth. These results demonstrate that rooting characteristics of white clover can be altered by hybridization with T. uniflorum, potentially improving water and nutrient acquisition and drought resistance. Root traits of T. uniflorum are likely to be adaptations to soil moisture and fertility in its natural environment. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Rooting depth and root depth distribution of Trifolium repens × T. uniflorum interspecific hybrids

PubMed Central

Nichols, S. N.; Hofmann, R. W.; Williams, W. M.; van Koten, C.

2016-01-01

Background and aims Traits related to root depth distribution were examined in Trifolium repens × T. uniflorum backcross 1 (BC1) hybrids to determine whether root characteristics of white clover could be improved by interspecific hybridization. Methods Two white clover cultivars, two T. uniflorum accessions and two BC1 populations were grown in 1 -m deep tubes of sand culture. Maximum rooting depth and root mass distribution were measured at four harvests over time, and root distribution data were fitted with a regression model to provide measures of root system shape. Morphological traits were measured at two depths at harvest 3. Key Results Root system shape of the hybrids was more similar to T. uniflorum than to white clover. The hybrids and T. uniflorum had a higher rate of decrease in root mass with depth than white clover, which would result in higher proportions of root mass in the upper profile. Percentage total root mass at 100–200 mm depth was higher for T. uniflorum than white clover, and for Crusader BC1 than ‘Crusader’. Roots of the hybrids and T. uniflorum also penetrated deeper than those of white clover. T. uniflorum had thicker roots at 50–100 mm deep than the other entries, and more of its fine root mass at 400–500 mm. The hybrids and white clover had more of their fine root mass higher in the profile. Consequently, T. uniflorum had a higher root length density at 400–500 mm than most entries, and a smaller decrease in root length density with depth. Conclusions These results demonstrate that rooting characteristics of white clover can be altered by hybridization with T. uniflorum, potentially improving water and nutrient acquisition and drought resistance. Root traits of T. uniflorum are likely to be adaptations to soil moisture and fertility in its natural environment. PMID:27208735

The molecular network governing nodule organogenesis and infection in the model legume Lotus japonicus.

PubMed

Madsen, Lene H; Tirichine, Leïla; Jurkiewicz, Anna; Sullivan, John T; Heckmann, Anne B; Bek, Anita S; Ronson, Clive W; James, Euan K; Stougaard, Jens

2010-04-12

Bacterial infection of interior tissues of legume root nodules is controlled at the epidermal cell layer and is closely coordinated with progressing organ development. Using spontaneous nodulating Lotus japonicus plant mutants to uncouple nodule organogenesis from infection, we have determined the role of 16 genes in these two developmental processes. We show that host-encoded mechanisms control three alternative entry processes operating in the epidermis, the root cortex and at the single cell level. Single cell infection did not involve the formation of trans-cellular infection threads and was independent of host Nod-factor receptors and bacterial Nod-factor signals. In contrast, Nod-factor perception was required for epidermal root hair infection threads, whereas primary signal transduction genes preceding the secondary Ca2+ oscillations have an indirect role. We provide support for the origin of rhizobial infection through direct intercellular epidermal invasion and subsequent evolution of crack entry and root hair invasions observed in most extant legumes.

Impaired micturition reflex caused by acute selective dorsal or ventral root(s) rhizotomy in anesthetized rats.

PubMed

Liao, Jiuan-Miaw; Cheng, Chen-Li; Lee, Shin-Da; Chen, Gin-Den; Chen, Kuo-Jung; Yang, Chao-Hsun; Pan, Shwu-Fen; Chen, Mei-Jung; Huang, Pei-Chen; Lin, Tzer-Bin

2006-01-01

To clarify the contributions of parasympathetic inputs and outputs to the micturition reflex. Intra-vesical pressure (IVP), external urethral sphincter electromyogram (EMG), pelvic afferent nerve activities (PANA), and pelvic efferent nerve activities (PENA) as well as the time-derived IVP (dIVP, an index of bladder contractility) were evaluated in intact and acute dorsal or ventral root(s) rhizotomized (DRX and VRX, respectively) rats. In DRX rats, when compared with that in intact stage, the voiding frequency was decreased (75 +/- 15% of intact, P < 0.05, n = 8), while the threshold pressure to trigger voiding contractions was significantly increased (187 +/- 75% of intact, P < 0.05, n = 8). In addition, several insufficient contractions (5.3 +/- 3.5 contractions/voiding, P < 0.05, n = 8) occurred in ahead of each voiding contraction. On the other hand, in VRX rats, the peak and rebound IVP were significantly decreased (90 +/- 3.5% and 75 +/- 11.3% of intact, P < 0.01, n = 8), while the threshold pressure was not affected (102 +/- 11% of intact, P = NS, n = 8). The time-derived parameters were significantly decreased in VRX (peak dIVP, 78 +/- 10.2%, rebound dIVP, 75 +/- 15.6%, minimal dIVP, 68 +/- 14% of intact, P < 0.01, n = 8) but only peak dIVP was decreased (85 +/- 11% of intact, P < 0.01, n = 8) in DRX rats. Acute selective DRX and VRX rat can be an animal model to investigate peripheral neural control in micturition functions.

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.

Bladder volume-dependent excitatory and inhibitory influence of lumbosacral dorsal and ventral roots on bladder activity in rats

PubMed Central

Sugaya, Kimio; de Groat, William C.

2011-01-01

This study was undertaken to examine the role of the afferent and efferent pathways of the lumbosacral spinal nerve roots in the tonic control of bladder activity. Changes of isovolumetric bladder activity were recorded in 21 sympathectomized female rats under urethane anesthesia following transection of the dorsal (DRT) and ventral (VRT) lumbosacral spinal roots, and after intraperitoneal administration of hexamethonium. DRT altered the baseline intravesical pressure in a bladder volume-dependent manner in each animal. The percent change of baseline pressure after VRT following DRT was also dependent upon bladder volume. The percent change of baseline pressure after VRT alone was similarly dependent on bladder volume, but not after VRT followed by DRT. The percent change of baseline intravesical pressure (y)(−9 to +8 cm H2O, −56 to +46%) after DRT and VRT depended upon bladder volume (x)(y = 44.7 x −40.4) in all rats. Hexamethonium increased the amplitude of small myogenic bladder contractions after DRT and VRT. In conclusion, the bladder is tonically excited or inhibited by a local reflex pathway and by a parasympathetic reflex pathway that depends on connections with the lumbosacral spinal cord and the pelvic nerves. Both reflex mechanisms are influenced by bladder volume. PMID:17878597

76 FR 1592 - Submission for OMB Review; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-11

...: Advanced Meat Recovery Systems. OMB Control Number: 0583-0130. Summary of Collection: The Food Safety and... Recovery (AMR) systems ensure that bones used for AMR systems do not contain brain, trigeminal ganglia, or... dorsal root ganglia (DRG); to document their testing protocols, to assess manner that does not cause...

Salvage C2 ganglionectomy after C2 nerve root decompression provides similar pain relief as a single surgical procedure for intractable occipital neuralgia.

PubMed

Pisapia, Jared M; Bhowmick, Deb A; Farber, Roger E; Zager, Eric L

2012-02-01

To determine the effectiveness of C2 nerve root decompression and C2 dorsal root ganglionectomy for intractable occipital neuralgia (ON) and C2 ganglionectomy after pain recurrence following initial decompression. A retrospective review was performed of the medical records of patients undergoing surgery for ON. Pain relief at the time of the most recent follow-up was rated as excellent (headache relieved), good (headache improved), or poor (headache unchanged or worse). Telephone contact supplemented chart review, and patients rated their preoperative and postoperative pain on a 10-point numeric scale. Patient satisfaction and disability were also examined. Of 43 patients, 29 were available for follow-up after C2 nerve root decompression (n = 11), C2 dorsal root ganglionectomy (n = 10), or decompression followed by ganglionectomy (n = 8). Overall, 19 of 29 patients (66%) experienced a good or excellent outcome at most recent follow-up. Among the 19 patients who completed the telephone questionnaire (mean follow-up 5.6 years), patients undergoing decompression, ganglionectomy, or decompression followed by ganglionectomy experienced similar outcomes, with mean pain reduction ratings of 5 ± 4.0, 4.5 ± 4.1, and 5.7 ± 3.5. Of 19 telephone responders, 13 (68%) rated overall operative results as very good or satisfactory. In the third largest series of surgical intervention for ON, most patients experienced favorable postoperative pain relief. For patients with pain recurrence after C2 decompression, salvage C2 ganglionectomy is a viable surgical option and should be offered with the potential for complete pain relief and improved quality of life (QOL). Copyright © 2012. Published by Elsevier Inc.

7 CFR 319.37-14 - Ports of entry.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Ports of entry. 319.37-14 Section 319.37-14 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs, Seeds, and Other Plant Products 1,2 § 319.37-14 Ports of...

7 CFR 319.37-14 - Ports of entry.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 5 2011-01-01 2011-01-01 false Ports of entry. 319.37-14 Section 319.37-14 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs, Seeds, and Other Plant Products 1,2 § 319.37-14 Ports of...

Improving laboratory data entry quality using Six Sigma.

PubMed

Elbireer, Ali; Le Chasseur, Julie; Jackson, Brooks

2013-01-01

The Uganda Makerere University provides clinical laboratory support to over 70 clients in Uganda. With increased volume, manual data entry errors have steadily increased, prompting laboratory managers to employ the Six Sigma method to evaluate and reduce their problems. The purpose of this paper is to describe how laboratory data entry quality was improved by using Six Sigma. The Six Sigma Quality Improvement (QI) project team followed a sequence of steps, starting with defining project goals, measuring data entry errors to assess current performance, analyzing data and determining data-entry error root causes. Finally the team implemented changes and control measures to address the root causes and to maintain improvements. Establishing the Six Sigma project required considerable resources and maintaining the gains requires additional personnel time and dedicated resources. After initiating the Six Sigma project, there was a 60.5 percent reduction in data entry errors from 423 errors a month (i.e. 4.34 Six Sigma) in the first month, down to an average 166 errors/month (i.e. 4.65 Six Sigma) over 12 months. The team estimated the average cost of identifying and fixing a data entry error to be $16.25 per error. Thus, reducing errors by an average of 257 errors per month over one year has saved the laboratory an estimated $50,115 a year. The Six Sigma QI project provides a replicable framework for Ugandan laboratory staff and other resource-limited organizations to promote quality environment. Laboratory staff can deliver excellent care at a lower cost, by applying QI principles. This innovative QI method of reducing data entry errors in medical laboratories may improve the clinical workflow processes and make cost savings across the health care continuum.

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.

Comprehensive Method for Culturing Embryonic Dorsal Root Ganglion Neurons for Seahorse Extracellular Flux XF24 Analysis

PubMed Central

Lange, Miranda; Zeng, Yan; Knight, Andrew; Windebank, Anthony; Trushina, Eugenia

2012-01-01

Changes in mitochondrial dynamics and function contribute to progression of multiple neurodegenerative diseases including peripheral neuropathies. The Seahorse Extracellular Flux XF24 analyzer provides a comprehensive assessment of the relative state of glycolytic and aerobic metabolism in live cells making this method instrumental in assessing mitochondrial function. One of the most important steps in the analysis of mitochondrial respiration using the Seahorse XF24 analyzer is plating a uniform monolayer of firmly attached cells. However, culturing of primary dorsal root ganglion (DRG) neurons is associated with multiple challenges, including their propensity to form clumps and detach from the culture plate. This could significantly interfere with proper analysis and interpretation of data. We have tested multiple cell culture parameters including coating substrates, culture medium, XF24 microplate plastics, and plating techniques in order to optimize plating conditions. Here we describe a highly reproducible method to obtain neuron-enriched monolayers of securely attached dissociated primary embryonic (E15) rat DRG neurons suitable for analysis with the Seahorse XF24 platform. PMID:23248613

Multielectrode array recordings of bladder and perineal primary afferent activity from the sacral dorsal root ganglia

NASA Astrophysics Data System (ADS)

Bruns, Tim M.; Gaunt, Robert A.; Weber, Douglas J.

2011-10-01

The development of bladder and bowel neuroprostheses may benefit from the use of sensory feedback. We evaluated the use of high-density penetrating microelectrode arrays in sacral dorsal root ganglia (DRG) for recording bladder and perineal afferent activity. Arrays were inserted in S1 and S2 DRG in three anesthetized cats. Neural signals were recorded while the bladder volume was modulated and mechanical stimuli were applied to the perineal region. In two experiments, 48 units were observed that tracked bladder pressure with their firing rates (79% from S2). At least 50 additional units in each of the three experiments (274 total; 60% from S2) had a significant change in their firing rates during one or more perineal stimulation trials. This study shows the feasibility of obtaining bladder-state information and other feedback signals from the pelvic region with a sacral DRG electrode interface located in a single level. This natural source of feedback would be valuable for providing closed-loop control of bladder or other pelvic neuroprostheses.

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.

Comprehensive Method for Culturing Embryonic Dorsal Root Ganglion Neurons for Seahorse Extracellular Flux XF24 Analysis.

PubMed

Lange, Miranda; Zeng, Yan; Knight, Andrew; Windebank, Anthony; Trushina, Eugenia

2012-01-01

Changes in mitochondrial dynamics and function contribute to progression of multiple neurodegenerative diseases including peripheral neuropathies. The Seahorse Extracellular Flux XF24 analyzer provides a comprehensive assessment of the relative state of glycolytic and aerobic metabolism in live cells making this method instrumental in assessing mitochondrial function. One of the most important steps in the analysis of mitochondrial respiration using the Seahorse XF24 analyzer is plating a uniform monolayer of firmly attached cells. However, culturing of primary dorsal root ganglion (DRG) neurons is associated with multiple challenges, including their propensity to form clumps and detach from the culture plate. This could significantly interfere with proper analysis and interpretation of data. We have tested multiple cell culture parameters including coating substrates, culture medium, XF24 microplate plastics, and plating techniques in order to optimize plating conditions. Here we describe a highly reproducible method to obtain neuron-enriched monolayers of securely attached dissociated primary embryonic (E15) rat DRG neurons suitable for analysis with the Seahorse XF24 platform.

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.

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

The Distributions of Voltage-Gated K+ current Subtypes in Different Cell Sizes from Adult Mouse Dorsal Root Ganglia.

PubMed

Sheng, Anqi; Hong, Jiangru; Zhang, Lulu; Zhang, Yan; Zhang, Guangqin

2018-03-29

Voltage-gated K + (K V ) currents play a crucial role in regulating pain by controlling neuronal excitability, and are divided into transient A-type currents (I A ) and delayed rectifier currents (I K ). The dorsal root ganglion (DRG) neurons are heterogeneous and the subtypes of K V currents display different levels in distinct cell sizes. To observe correlations of the subtypes of K V currents with DRG cell sizes, K V currents were recorded by whole-cell patch clamp in freshly isolated mouse DRG neurons. Results showed that I A occupied a high proportion in K V currents in medium- and large-diameter DRG neurons, whereas I K possessed a larger proportion of K V currents in small-diameter DRG neurons. A lower correlation was found between the proportion of I A or I K in K V currents and cell sizes. These data suggest that I A channels are mainly expressed in medium and large cells and I K channels are predominantly expressed in small cells.

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.

Common symbiosis genes CERBERUS and NSP1 provide additional insight into the establishment of arbuscular mycorrhizal and root nodule symbioses in Lotus japonicus.

PubMed

Nagae, Miwa; Takeda, Naoya; Kawaguchi, Masayoshi

2014-01-01

Arbuscular mycorrhizal symbiosis (AMS) and root nodule symbiosis (RNS) share several common symbiotic components, and many of the common symbiosis mutants block the entry of symbionts into the roots. We recently reported that CERBERUS (an E3 ubiquitin ligase) and NSP1 (a GRAS family transcription factor), required for RNS, also modulate AMS development in Lotus japonicus. The novel common symbiosis mutants, cerberus and nsp1, have low colonization of arbuscular mycorrhiza (AM) fungi, caused by a defect in internal hyphal elongation and by a decreased fungal entry into the roots, respectively. Here, we showed that CERBERUS was induced at the sites of symbiotic fungal or bacterial infection. NSP1 has been implicated in a strigolactone biosynthesis gene DWARF27 expression. Nevertheless, in nsp1, DWARF27 was induced by inoculation with AM fungi, implying the existence of a NSP1-independent regulatory mechanism of strigolactone biosynthesis during AMS establishment. These results support functional analysis of CERBERUS and NSP1, and also contribute to elucidation of common mechanisms in AMS and RNS.

Neurobiological roots of language in primate audition: common computational properties.

PubMed

Bornkessel-Schlesewsky, Ina; Schlesewsky, Matthias; Small, Steven L; Rauschecker, Josef P

2015-03-01

Here, we present a new perspective on an old question: how does the neurobiology of human language relate to brain systems in nonhuman primates? We argue that higher-order language combinatorics, including sentence and discourse processing, can be situated in a unified, cross-species dorsal-ventral streams architecture for higher auditory processing, and that the functions of the dorsal and ventral streams in higher-order language processing can be grounded in their respective computational properties in primate audition. This view challenges an assumption, common in the cognitive sciences, that a nonhuman primate model forms an inherently inadequate basis for modeling higher-level language functions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Immunization Elicits Antigen-Specific Antibody Sequestration in Dorsal Root Ganglia Sensory Neurons

PubMed Central

Gunasekaran, Manojkumar; Chatterjee, Prodyot K.; Shih, Andrew; Imperato, Gavin H.; Addorisio, Meghan; Kumar, Gopal; Lee, Annette; Graf, John F.; Meyer, Dan; Marino, Michael; Puleo, Christopher; Ashe, Jeffrey; Cox, Maureen A.; Mak, Tak W.; Bouton, Chad; Sherry, Barbara; Diamond, Betty; Andersson, Ulf; Coleman, Thomas R.; Metz, Christine N.; Tracey, Kevin J.; Chavan, Sangeeta S.

2018-01-01

The immune and nervous systems are two major organ systems responsible for host defense and memory. Both systems achieve memory and learning that can be retained, retrieved, and utilized for decades. Here, we report the surprising discovery that peripheral sensory neurons of the dorsal root ganglia (DRGs) of immunized mice contain antigen-specific antibodies. Using a combination of rigorous molecular genetic analyses, transgenic mice, and adoptive transfer experiments, we demonstrate that DRGs do not synthesize these antigen-specific antibodies, but rather sequester primarily IgG1 subtype antibodies. As revealed by RNA-seq and targeted quantitative PCR (qPCR), dorsal root ganglion (DRG) sensory neurons harvested from either naïve or immunized mice lack enzymes (i.e., RAG1, RAG2, AID, or UNG) required for generating antibody diversity and, therefore, cannot make antibodies. Additionally, transgenic mice that express a reporter fluorescent protein under the control of Igγ1 constant region fail to express Ighg1 transcripts in DRG sensory neurons. Furthermore, neural sequestration of antibodies occurs in mice rendered deficient in neuronal Rag2, but antibody sequestration is not observed in DRG sensory neurons isolated from mice that lack mature B cells [e.g., Rag1 knock out (KO) or μMT mice]. Finally, adoptive transfer of Rag1-deficient bone marrow (BM) into wild-type (WT) mice or WT BM into Rag1 KO mice revealed that antibody sequestration was observed in DRG sensory neurons of chimeric mice with WT BM but not with Rag1-deficient BM. Together, these results indicate that DRG sensory neurons sequester and retain antigen-specific antibodies released by antibody-secreting plasma cells. Coupling this work with previous studies implicating DRG sensory neurons in regulating antigen trafficking during immunization raises the interesting possibility that the nervous system collaborates with the immune system to regulate antigen-mediated responses. PMID:29755449

The effects of anticonvulsants on 4-aminopyridine-induced bursting: in vitro studies on rat peripheral nerve and dorsal roots.

PubMed Central

Lees, G.

1996-01-01

1. Aminopyridines have been used as beneficial symptomatic treatments in a variety of neurological conditions including multiple sclerosis but have been associated with considerable toxicity in the form of abdominal pain, paraesthesias and (rarely) convulsions. 2. Extracellular and intracellular recording was used to characterize action potentials in rat sciatic nerves and dorsal roots and the effects of 4-aminopyridine (4-AP). 3. In sciatic nerve trunks, 1 mM 4-AP produced pronounced after potentials at room temperature secondary to regenerative firing in affected axons (5-10 spikes per stimulus). At physiological temperatures, after potentials (2-3 spikes) were greatly attenuated in peripheral axons. 4. 4-AP evoked more pronounced and prolonged after discharges in isolated dorsal roots at 37 degrees C (3-5.5 mV and 80-100 ms succeeded by a smaller inhibitory/depolarizing voltage shift) which were used to assess the effects of anticonvulsants. 5. Phenytoin, carbamazepine and lamotrigine dose-dependently reduced the area of 4-AP-induced after potentials at 100 and 320 microM but the amplitude of compound action potentials (evoked at 0.5 Hz) was depressed in parallel. 6. The tonic block of sensory action potentials by all three drugs (at 320 microM) was enhanced by high frequency stimulation (5-500 Hz). 7. The lack of selectivity of these frequency-dependent Na+ channel blockers for burst firing compared to low-frequency spikes, is discussed in contrast to their effects on 4-AP-induced seizures and paroxysmal activity in CNS tissue (which is associated with large and sustained depolarizing plateau potentials). 8. In conclusion, these in vitro results confirm the marked sensitivity of sensory axons to 4-AP (the presumptive basis for paraesthesias). Burst firing was not preferentially impaired at relatively high concentrations suggesting that anticonvulsants will not overcome the toxic peripheral actions of 4-AP in neurological patients. PMID:8821551

The role of TRPM8 in the Guinea-pig bladder-cooling reflex investigated using a novel TRPM8 antagonist.

PubMed

Gardiner, Jennifer C; Kirkup, Anthony J; Curry, John; Humphreys, Sian; O'Regan, Paul; Postlethwaite, Michael; Young, Kimberley C; Kitching, Linda; Ethell, Brian T; Winpenny, David; McMurray, Gordon

2014-10-05

Patients with overactive bladder often exhibit abnormal bladder contractions in response to intravesical cold saline (positive ice-water test). The molecular entity involved in cold sensation within the urinary bladder is unknown, but a potential candidate is the ion channel, transient receptor potential (melastatin)-8 (TRPM8). The objective of the present study was to investigate the role of TRPM8 in a bladder-cooling reflex evoked in anaesthetised guinea-pigs that is comparable to the positive ice-water test seen in patients. Guinea-pig TRPM8 was cloned from L6 dorsal root ganglia (DRG) and expressed in HEK293 cells. Functional agonist- and cold-induced Ca2+ influx and electrophysiology assays were performed in these cells, and for comparison in HEK293 cells expressing human TRPM8, using a novel TRPM8 antagonist, the S-enantiomer of 1-phenylethyl 4-(benzyloxy)-3-methoxybenzyl (2-aminoethyl) carbamate hydrochloride (PBMC). Potency data from these assays was used to calculate intravenous infusion protocols for targeted plasma concentrations of PBMC in studies on micturition reflexes evoked by intravesical infusion of menthol or cold saline in anaesthetised guinea-pigs. Tissue expression of TRPM8 in guinea-pig bladder, urethra and in dorsal root ganglia neurones traced from the bladder was also investigated. TRPM8 mRNA and protein were detected in L6 dorsal root ganglia, bladder urothelium and smooth muscle. PBMC antagonised in vitro activation of human and guinea-pig TRPM8 and reversed menthol and cold-induced facilitation of the micturition reflex at plasma concentrations consistent with in vitro potencies. The present data suggest that the bladder-cooling reflex in the guinea-pig involves TRPM8. The potential significance of TRPM8 in bladder disease states deserves future investigation. Copyright © 2014 Elsevier B.V. All rights reserved.

Nogo-receptor gene activity: cellular localization and developmental regulation of mRNA in mice and humans.

PubMed

Josephson, Anna; Trifunovski, Alexandra; Widmer, Hans Ruedi; Widenfalk, Johan; Olson, Lars; Spenger, Christian

2002-11-18

Nogo (reticulon-4) is a myelin-associated protein that is expressed in three different splice variants, Nogo-A, Nogo-B, and Nogo-C. Nogo-A inhibits neurite regeneration in the central nervous system. Messenger RNA encoding Nogo is expressed in oligodendrocytes and central and peripheral neurons, but not in astrocytes or Schwann cells. Nogo is a transmembraneous protein; the extracellular domain is termed Nogo-66, and a Nogo-66-receptor (Nogo-R) has been identified. We performed in situ hybridization in human and mouse nervous tissues to map the cellular distribution of Nogo-R gene activity patterns in fetal and adult human spinal cord and sensory ganglia, adult human brain, and the nervous systems of developing and adult mice. In the human fetus Nogo-R was transcribed in the ventral horn of the spinal cord and in dorsal root ganglia. In adult human tissues Nogo-R gene activity was found in neocortex, hippocampus, amygdala, and a subset of large and medium-sized neurons of the dorsal root ganglia. Nogo-R mRNA was not expressed in the adult human spinal cord at detectable levels. In the fetal mouse, Nogo-R was diffusely expressed in brain, brainstem, trigeminal ganglion, spinal cord, and dorsal root ganglia at all stages. In the adult mouse strong Nogo-R mRNA expression was found in neurons in neocortex, hippocampus, amygdala, habenula, thalamic nuclei, brainstem, the granular cell layer of cerebellum, and the mitral cell layer of the olfactory bulb. Neurons in the adult mouse striatum, the medial septal nucleus, and spinal cord did not express Nogo-R mRNA at detectable levels. In summary, Nogo-66-R mRNA expression in humans and mice was observed in neurons of the developing nervous system Expression was downregulated in the adult spinal cord of both species, and specific expression patterns were seen in the adult brain. Copyright 2002 Wiley-Liss, Inc.

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

A new basal galeomorph shark (Synechodontiformes, Neoselachii) from the Early Jurassic of Europe

NASA Astrophysics Data System (ADS)

Klug, Stefanie; Kriwet, Jürgen

2008-05-01

Palaeospinacids are a group of basal galeomorph sharks and are placed in the order Synechodontiformes (Chondrichthyes, Neoselachii) ranging from the Permian to the Eocene. Currently, there is a controversy concerning the identity of diagnostic characters for distinguishing palaeospinacid genera because of very similar dental morphologies and the scarcity of articulated skeletal material. The most notable character for distinguishing species within the Palaeospinacidae is, however, the dental morphology. The main dental character uniting all palaeospinacids is the very specialised pseudopolyaulacorhize root vascularisation. A re-examination of articulated neoselachian skeletons from the Lower Jurassic of Lyme Regis (England) and Holzmaden (S Germany), and recently discovered specimens from the Upper Jurassic of the Solnhofen area and Nusplingen (S Germany) has yielded several hitherto unrecognised complete skeletons of the palaeospinacids Synechodus and Paraorthacodus enabling a re-evaluation of characters. These specimens indicate that the number of dorsal fins and the presence or absence of dorsal fin spines represent important features for identifying palaeospinacids. Synechodus bears two dorsal fins without fin spines, whereas Paraorthacodus only has a single dorsal fin lacking a fin spine directly in front of the caudal fin. All palaeospinacids from the Early Jurassic have two spines supporting the dorsal fins and are consequently assigned to a new genus, Palidiplospinax nov. gen. Three species are placed into the new taxon: Synechodus enniskilleni, S. occultidens and S. smithwoodwardi.

Xenon inhibits excitatory but not inhibitory transmission in rat spinal cord dorsal horn neurons

PubMed Central

2010-01-01

Background The molecular targets for the promising gaseous anaesthetic xenon are still under investigation. Most studies identify N-methyl-D-aspartate (NMDA) receptors as the primary molecular target for xenon, but the role of α-amino-3-hydroxy-5-methyl-4-isoxazole-4-propionic acid (AMPA) receptors is less clear. In this study we evaluated the effect of xenon on excitatory and inhibitory synaptic transmission in the superficial dorsal horn of the spinal cord using in vitro patch-clamp recordings from rat spinal cord slices. We further evaluated the effects of xenon on innocuous and noxious stimuli using in vivo patch-clamp method. Results In vitro, xenon decreased the amplitude and area under the curve of currents induced by exogenous NMDA and AMPA and inhibited dorsal root stimulation-evoked excitatory postsynaptic currents. Xenon decreased the amplitude, but not the frequency, of miniature excitatory postsynaptic currents. There was no discernible effect on miniature or evoked inhibitory postsynaptic currents or on the current induced by inhibitory neurotransmitters. In vivo, xenon inhibited responses to tactile and painful stimuli even in the presence of NMDA receptor antagonist. Conclusions Xenon inhibits glutamatergic excitatory transmission in the superficial dorsal horn via a postsynaptic mechanism. There is no substantial effect on inhibitory synaptic transmission at the concentration we used. The blunting of excitation in the dorsal horn lamina II neurons could underlie the analgesic effect of xenon. PMID:20444263

Crucial roles of NGF in dorsal horn plasticity in partially deafferentated cats.

PubMed

Liu, Jia; Chen, Shan-Shan; Dan, Qi-Qin; Rong, Rong; Zhou, Xue; Zhang, Lian-Feng; Wang, Ting-Hua

2011-04-01

Though exogenous nerve growth factor (NGF) has been implicated in spinal cord plasticity, whether endogenous NGF plays a crucial role has not been established in vivo. This study investigated first the role of endogenous NGF in spinal dorsal horn (DH) plasticity following removal of L1-L5 and L7-S2 dorsal root ganglions (DRGs) in cats. Co-culture of chick embryo DRG with DH condition media, protein band fishing by cells as well as western blot showed that NGF could promote neurite growth in vitro. Immunohistochemistry and in situ hybridization technique revealed an increase in the NGF and NGF mRNA immunoreactive cells in the DH after partial deafferentation. Lastly, after blocking with NGF antibody, choleragen subunit B horseradish peroxidase (CB-HRP) tracing showed a reduction in the neuronal sprouting observed in the DH. Our results demonstrated that in the cat, endogenous NGF plays a crucial role in DH plasticity after partial deafferentation.

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.

Rhizobial infection in Adesmia bicolor (Fabaceae) roots.

PubMed

Bianco, Luciana

2014-09-01

The native legume Adesmia bicolor shows nitrogen fixation efficiency via symbiosis with soil rhizobia. The infection mechanism by means of which rhizobia infect their roots has not been fully elucidated to date. Therefore, the purpose of the present study was to identify the infection mechanism in Adesmia bicolor roots. To this end, inoculated roots were processed following conventional methods as part of our root anatomy study, and the shape and distribution of root nodules were analyzed as well. Neither root hairs nor infection threads were observed in the root system, whereas infection sites-later forming nodules-were observed in the longitudinal sections. Nodules were found to form between the main root and the lateral roots. It can be concluded that in Adesmia bicolor, a bacterial crack entry infection mechanism prevails and that such mechanism could be an adaptive strategy of this species which is typical of arid environments.

Endodontic management of radix paramolaris with six canals: a clinical case report.

PubMed

Acharya, N; Singh, A; Samant, P S; Gautam, V

2013-01-01

Endodontic therapy of mandibular molars is a challenging task due to its varied root canal morphology. A mandibular first molar with additional buccal root (Radix paramolaris) and additional distolingual root (Radix Entomolaris) is an example of its varied anatomy. A successful management of atypical root canal configurations is an important aspect in determining the success rate of root canal therapy. The detail knowledge of the root morphology and canal anatomy allows the clinician for accurate location of the extra roots and canals and accordingly the refinement of the access cavity for the stress free entry of complex anatomy. Hence, for a successful root canal therapy, clinician must be aware of the external and internal anatomic variations .The aim of this clinical case report is to present and describe the unusual presence of two separate mesial roots and six root canals in mandibular first molar, detected during routine endodontic therapy.

Inflammatory Pain Reduces C Fiber Activity-Dependent Slowing in a Sex-Dependent Manner, Amplifying Nociceptive Input to the Spinal Cord

PubMed Central

McCormick, Barry; Lukito, Veny; Wilson, Kirsten L.

2017-01-01

C fibers display activity-dependent slowing (ADS), whereby repetitive stimulation (≥1 Hz) results in a progressive slowing of action potential conduction velocity, which manifests as a progressive increase in response latency. However, the impact of ADS on spinal pain processing has not been explored, nor whether ADS is altered in inflammatory pain conditions. To investigate, compound action potentials were made, from dorsal roots isolated from rats with or without complete Freund's adjuvant (CFA) hindpaw inflammation, in response to electrical stimulus trains. CFA inflammation significantly reduced C fiber ADS at 1 and 2 Hz stimulation rates. Whole-cell patch-clamp recordings in the spinal cord slice preparation with attached dorsal roots also demonstrated that CFA inflammation reduced ADS in the monosynaptic C fiber input to lamina I neurokinin 1 receptor-expressing neurons (1–10 Hz stimulus trains) without altering the incidence of synaptic response failures. When analyzed by sex, it was revealed that females display a more pronounced ADS that is reduced by CFA inflammation to a level comparable with males. Cumulative ventral root potentials evoked by long and short dorsal root stimulation lengths, to maximize and minimize the impact of ADS, respectively, demonstrated that reducing ADS facilitates spinal summation, and this was also sex dependent. This finding correlated with the behavioral observation of increased noxious thermal thresholds and enhanced inflammatory thermal hypersensitivity in females. We propose that sex/inflammation-dependent regulation of C fiber ADS can, by controlling the temporal relay of nociceptive inputs, influence the spinal summation of nociceptive signals contributing to sex/inflammation-dependent differences in pain sensitivity. SIGNIFICANCE STATEMENT The intensity of a noxious stimulus is encoded by the frequency of action potentials relayed by nociceptive C fibers to the spinal cord. C fibers conduct successive action potentials at progressively slower speeds, but the impact of this activity-dependent slowing (ADS) is unknown. Here we demonstrate that ADS is more prevalent in females than males and is reduced in an inflammatory pain model in females only. We also demonstrate a progressive delay of C fiber monosynaptic transmission to the spinal cord that is similarly sex and inflammation dependent. Experimentally manipulating ADS strongly influences spinal summation consistent with sex differences in behavioral pain thresholds. This suggests that ADS provides a peripheral mechanism that can regulate spinal nociceptive processing and pain sensation. PMID:28576935

[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 results in overexpression of caspase-3 in nerve root tissue and increase of DRG neuron apoptosis. Yiqi Huayu Recipe can inhibit the overexpression of caspase-3 and alleviate the apoptosis of DRG neurons after nerve injury.

Prevention of development of postoperative dysesthesia in transforaminal percutaneous endoscopic lumbar discectomy for intracanalicular lumbar disc herniation: floating retraction technique.

PubMed

Cho, J Y; Lee, S-H; Lee, H-Y

2011-10-01

Transforaminal percutaneous endoscopic lumbar discectomy (PELD) has become a routine surgical procedure because it is minimally invasive. Perioperative complications such as dural injury, infection, nerve root irritation and recurrence can occur not only with PELD, but also with conventional open microsurgery. In contrast, post-operative dysesthesia (POD) due to existing dorsal root ganglion (DRG) injury is a unique complication of PELD. When POD occurs, even if the traversing root has been successfully decompressed, it hinders swift recovery and delays the return to daily routines. Thus, prevention of POD is the key to successful and widespread use of PELD. From January 2006 to December 2008, 154 patients underwent percutaneous endoscopic discectomy by floating retraction technique at 160 disc levels under local anesthesia. This approach towards the superomedial border of the lower pedicle and the cannula can be placed by gentle retraction of the root with perineural fat instead of direct compression of dorsal root ganglion. The clinical outcomes were assessed using the Visual Analogue Scale (VAS, 0-10 point) for radicular pain and low back pain, and using the Oswestry Disability Index (ODI) for functional status. Perioperative complications and recurrence were reviewed. The mean age was 45 years, the mean operative time was 36 min and the mean follow-up period was 3.4 years. The mean hospital stay for endoscopic discectomy was 1.8 days. No patient underwent repeated PELD or convert microsurgery by incomplete removal of the ruptured particle. All patients experienced early relief of symptoms, as determined by VAS and ODI. No patient developed POD. 1 patient experienced dural injury. There was 1 case of discitis. The recurrence rate was 1.95% (3 patients). Transforaminal percutaneous endoscopic lumbar discectomy for intracanalicular lumbar disc herniation is a safe and effective procedure. The floating retraction technique is recommended to avoid development of POD. © Georg Thieme Verlag KG Stuttgart · New York.

Inhibitory actions of synthesised polyamine spider toxins and their analogues on Ca2+-activated Cl- currents recorded from cultured DRG neurones from neonatal rats.

PubMed

Sutton, K G; Stapleton, S R; Scott, R H

1998-07-24

The whole cell variant of the patch clamp technique was used to investigate the actions of polyamine spider toxins and their analogues on high voltage-activated Ca2+ currents and Ca2+-activated Cl- currents (I(Cl(Ca))). The actions of synthesised FTX (putative natural toxin from the American funnel web spider), sFTX-3.3, Orn-FTX-3.3, Lys-FTX-3.3, and argiotoxin-636 on cultured dorsal root ganglion neurones from neonatal rats were investigated. Synthesised FTX (1 microM) inhibited I(Cl(Ca)) but did not inhibit high voltage-activated Ca2+ currents. In contrast, sFTX-3.3 (10 microM) inhibited both high voltage-activated Ca2+ currents and the associated I(Cl(Ca)) in near equal proportions. Argiotoxin-636 (1-10 microM) inhibited I(Cl(Ca)) evoked by Ca2+ entry through voltage-activated channels and by intracellular photorelease of Ca2+ from a caged precursor DM-nitrophen. This data indicates that synthesised FTX and argiotoxin-636 directly inhibit Ca2+-activated Cl- channels. In conclusion, the potency of polyamines as non-selective inhibitors of Ca2+ channels and Ca2+-activated Cl- channels is in part determined by the presence of a terminal arginine and this may involve an interaction between terminal guanidino groups and Ca2+ binding sites.

Blastomeres show differential fate changes in 8-cell Xenopus laevis embryos that are rotated 90 degrees before first cleavage

NASA Technical Reports Server (NTRS)

Huang, S.; Johnson, K. E.; Wang, H. Z.

1998-01-01

To study the mechanisms of dorsal axis specification, the alteration in dorsal cell fate of cleavage stage blastomeres in axis-respecified Xenopus laevis embryos was investigated. Fertilized eggs were rotated 90 degrees with the sperm entry point up or down with respect to the gravitational field. At the 8-cell stage, blastomeres were injected with the lineage tracers, Texas Red- or FITC-Dextran Amines. The distribution of the labeled progeny was mapped at the tail-bud stages (stages 35-38) and compared with the fate map of an 8-cell embryo raised in a normal orientation. As in the normal embryos, each blastomere in the rotated embryos has a characteristic and predictable cell fate. After 90 degrees rotation the blastomeres in the 8-cell stage embryo roughly switched their position by 90 degrees, but the fate of the blastomeres did not simply show a 90 degrees switch appropriate for their new location. Four types of fate change were observed: (i) the normal fate of the blastomere is conserved with little change; (ii) the normal fate is completely changed and a new fate is adopted according to the blastomere's new position: (iii) the normal fate is completely changed, but the new fate is not appropriate for its new position; and (4) the blastomere partially changed its fate and the new fate is a combination of its original fate and a fate appropriate to its new location. According to the changed fates, the blastomeres that adopt dorsal fates were identified in rotated embryos. This identification of dorsal blastomeres provides basic important information for further study of dorsal signaling in Xenopus embryos.

Deep cytoplasmic rearrangements in axis-respecified Xenopus embryos

NASA Technical Reports Server (NTRS)

Denegre, J. M.; Danilchik, M. V.

1993-01-01

In fertilized eggs of the frog Xenopus, the vegetal yolk mass rotates away from the future dorsal side (J. P. Vincent and J. Gerhart, 1987, Dev. Biol. 123, 526-539), and a major rearrangement of the deep animal hemisphere cytoplasm produces a characteristic swirl in the prospective dorsal side (M. V. Danilchik and J. M. Denegre, 1991, Development 111, 845-856). The relationship between this swirl and determination of the dorsal-ventral axis was further investigated by attempting to experimentally separate the positions of the swirl and the dorsal-ventral axis. Eggs were obliquely oriented in the gravity field to respecify the direction of yolk mass rotation and the position of the dorsal-ventral axis. When yolk mass rotation occurred in the absence of a sperm, as in activated eggs, a swirl pattern formed on the side away from which the yolk mass had rotated. In fertilized eggs tipped with the sperm entry point (SEP) down or to the side, swirl patterns were always found to form on the side away from which the yolk mass was displaced. However, in eggs tipped SEP up, in which the yolk mass was forced to rotate away from the SEP, more complicated rearrangements were observed in addition to the rotation-oriented swirl. Because the direction of yolk mass rotation was found to be influenced by both gravity and the actual position of the SEP in obliquely oriented eggs (SEP to the side), such complicated rearrangement patterns may result from opposing forces generated by both yolk mass rotation and the expanding sperm aster. Thus, except in cases in which the influences of SEP position and unit gravity opposed each other, it was not possible to experimentally separate the position of the deep cytoplasmic swirl from the direction of yolk mass rotation, and therefore the position of the prospective dorsal side.

Evaluation of the synuclein-y (SNCG) gene as a PPARy target in murine adipocytes, dorsal root ganglia somatosensory neurons, and human adipose tissue

USDA-ARS?s Scientific Manuscript database

Synuclein-gamma is highly expressed in both adipocytes and peripheral nervous system (PNS) somatosensory neurons. Its mRNA is induced during adipogenesis, increased in obese human white adipose tissue (WAT), may be coordinately regulated with leptin, and is decreased following treatment of murine 3T...

Neuron-glial communication mediated by TNF-α and glial activation in dorsal root ganglia in visceral inflammatory hypersensitivity.

PubMed

Song, Dan-dan; Li, Yong; Tang, Dong; Huang, Li-ya; Yuan, Yao-zong

2014-05-01

Communication between neurons and glia in the dorsal root ganglia (DRG) and the central nervous system is critical for nociception. Both glial activation and proinflammatory cytokine induction underlie this communication. We investigated whether satellite glial cell (SGC) and tumor necrosis factor-α (TNF-α) activation in DRG participates in a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced rat model of visceral hyperalgesia. In TNBS-treated rats, TNF-α expression increased in DRG and was colocalized to SGCs enveloping a given neuron. These SGCs were activated as visualized under electron microscopy: they had more elongated processes projecting into the connective tissue space and more gap junctions. When nerves attached to DRG (L6-S1) were stimulated with a series of electrical stimulations, TNF-α were released from DRG in TNBS-treated animals compared with controls. Using a current clamp, we noted that exogenous TNF-α (2.5 ng/ml) increased DRG neuron activity, and visceral pain behavioral responses were reversed by intrathecal administration of anti-TNF-α (10 μg·kg(-1)·day(-1)). Based on our findings, TNF-α and SGC activation in neuron-glial communication are critical in inflammatory visceral hyperalgesia.

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.

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.

Characterization of in vitro transcriptional responses of dorsal root ganglia cultured in the presence and absence of blastema cells from regenerating salamander limbs

PubMed Central

Athippozhy, Antony; Lehrberg, Jeffrey; Monaghan, James R.; Gardiner, David M.

2014-01-01

Abstract During salamander limb regeneration, nerves provide signals that induce the formation of a mass of proliferative cells called the blastema. To better understand these signals, we developed a blastema−dorsal root ganglia (DRG) co‐culture model system to test the hypothesis that nerves differentially express genes in response to cues provided by the blastema. DRG with proximal and distal nerve trunks were isolated from axolotls (Ambystoma mexicanum), cultured for 5 days, and subjected to microarray analysis. Relative to freshly isolated DRG, 1541 Affymetrix probe sets were identified as differentially expressed and many of the predicted genes are known to function in injury and neurodevelopmental responses observed for mammalian DRG. We then cultured 5‐day DRG explants for an additional 5 days with or without co‐cultured blastema cells. On day 10, we identified 27 genes whose expression in cultured DRG was significantly affected by the presence or absence of blastema cells. Overall, our study established a DRG−blastema in vitro culture system and identified candidate genes for future investigations of axon regrowth, nerve−blastema signaling, and neural regulation of limb regeneration. PMID:25750744

Basic fibroblast growth factor (bFGF) facilitates differentiation of adult dorsal root ganglia-derived neural stem cells toward Schwann cells by binding to FGFR-1 through MAPK/ERK activation.

PubMed

Gu, Yun; Xue, Chenbin; Zhu, Jianbin; Sun, Hualin; Ding, Fei; Cao, Zheng; Gu, Xiaosong

2014-04-01

Considerable research has been devoted to unraveling the regulation of neural stem cell (NSC) differentiation. The responses of NSCs to various differentiation-inducing stimuli, however, are still difficult to estimate. In this study, we aimed to search for a potent growth factor that was able to effectively induce differentiation of NSCs toward Schwann cells. NSCs were isolated from dorsal root ganglia (DRGs) of adult rats and identified by immunostaining. Three different growth factors were used to stimulate the differentiation of DRG-derived NSCs (DRG-NSCs). We found that among these three growth factors, bFGF was the strongest inducer for the glial differentiation of DRG-NSCs, and bFGF induced the generation of an increased number of Schwann cell-like cells as compared to nerve growth factor (NGF) and neuregulin1-β (NRG). These Schwann cell-like cells demonstrated the same characteristics as those of primary Schwann cells. Furthermore, we noted that bFGF-induced differentiation of DRG-NSCs toward Schwann cells might be mediated by binding to fibroblast growth factor receptor-1 (FGFR-1) through activation of MAPK/ERK signal pathway.

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.

Targeting dorsal root ganglia and primary sensory neurons for the treatment of chronic pain

PubMed Central

Berta, Temugin; Qadri, Yawar; Tan, Ping-Heng; Ji, Ru-Rong

2018-01-01

Introduction Currently the treatment of chronic pain is inadequate and compromised by debilitating central nervous system side effects. Here we discuss new therapeutic strategies that target dorsal root ganglia (DRGs) in the peripheral nervous system for a better and safer treatment of chronic pain. Areas covered The DRGs contain the cell bodies of primary sensory neurons including nociceptive neurons. After painful injuries, primary sensory neurons demonstrate maladaptive molecular changes in DRG cell bodies and in their axons. These changes result in hypersensitivity and hyperexcitability of sensory neurons (peripheral sensitization) and are crucial for the onset and maintenance of chronic pain. We discuss the following new strategies to target DRGs and primary sensory neurons as a means of alleviating chronic pain and minimizing side effects: inhibition of sensory neuron-expressing ion channels such as TRPA1, TRPV1, and Nav1.7, selective blockade of C- and Aβ-afferent fibers, gene therapy, and implantation of bone marrow stem cells. Expert opinion These peripheral pharmacological treatments, as well as gene and cell therapies, aimed at DRG tissues and primary sensory neurons can offer better and safer treatments for inflammatory, neuropathic, cancer, and other chronic pain states. PMID:28480765

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

Pulsed Radiofrequency of Dorsal Root Ganglia for the Treatment of Complex Regional Pain Syndrome in an Adolescent with Poliomyelitis Sequel: A Case Report.

PubMed

Apiliogullari, Seza; Aydin, Bahattin Kerem; Onal, Ozkan; Kirac, Yunus; Celik, Jale Bengi

2015-07-01

Complex regional pain syndrome (CRPS) is a painful and disabling syndrome in which the patient presents with neuropathic pain, edema, or vasomotor or pseudomotor abnormalities that are often refractory to treatment. Polio paralysis is caused by the damage or destruction of motor neurons in the spine, which lead to corresponding muscle paralysis. This report is a case report on the application of a pulsed radiofrequency (PRF) current to dorsal root ganglia (DRG) for the treatment of CRPS type 1 in an adolescent patient. Single case report. Selcuk University Hospital. A 16-year-old girl who suffered from CRPS type 1 secondary to surgeries for the sequelae of poliomyelitis. PRF current application to the lumbar 4 and lumbar 5 DRG. Pain reduction. The patient had complete resolution of her symptoms, which was maintained at a 6-month follow-up. This case illustrates that PRF applied to lumbar 4 and lumbar 5 DRG may play a significant role in CRPS type 1 management after the surgical treatment of poliomyelitis sequelae in adolescent patients. Further randomized, controlled studies are needed to support this argument. Wiley Periodicals, Inc.

Age-related changes in the function and structure of the peripheral sensory pathway in mice.

PubMed

Canta, Annalisa; Chiorazzi, Alessia; Carozzi, Valentina Alda; Meregalli, Cristina; Oggioni, Norberto; Bossi, Mario; Rodriguez-Menendez, Virginia; Avezza, Federica; Crippa, Luca; Lombardi, Raffaella; de Vito, Giuseppe; Piazza, Vincenzo; Cavaletti, Guido; Marmiroli, Paola

2016-09-01

This study is aimed at describing the changes occurring in the entire peripheral nervous system sensory pathway along a 2-year observation period in a cohort of C57BL/6 mice. The neurophysiological studies evidenced significant differences in the selected time points corresponding to childhood, young adulthood, adulthood, and aging (i.e., 1, 7, 15, and 25 months of age), with a parabolic course as function of time. The pathological assessment allowed to demonstrate signs of age-related changes since the age of 7 months, with a remarkable increase in both peripheral nerves and dorsal root ganglia at the subsequent time points. These changes were mainly in the myelin sheaths, as also confirmed by the Rotating-Polarization Coherent-Anti-stokes-Raman-scattering microscopy analysis. Evident changes were also present at the morphometric analysis performed on the peripheral nerves, dorsal root ganglia neurons, and skin biopsies. This extensive, multimodal characterization of the peripheral nervous system changes in aging provides the background for future mechanistic studies allowing the selection of the most appropriate time points and readouts according to the investigation aims. Copyright © 2016 Elsevier Inc. All rights reserved.

Distribution of binding sites for the plant lectin Ulex europaeus agglutinin I on primary sensory neurones in seven different mammalian species.

PubMed

Gerke, Michelle B; Plenderleith, Mark B

2002-01-01

There is an increasing body of evidence to suggest that different functional classes of neurones express characteristic cell-surface carbohydrates. Previous studies have shown that the plant lectin Ulex europaeus agglutinin-I (UEA) binds to a population of small to medium diameter primary sensory neurones in rabbits and humans. This suggests that a fucose-containing glycoconjugate may be expressed by nociceptive primary sensory neurones. In order to determine the extent to which this glycoconjugate is expressed by other species, in the current study, we have examined the distribution of UEA-binding sites on primary sensory neurones in seven different mammals. Binding sites for UEA were associated with the plasma membrane and cytoplasmic granules of small to medium dorsal root ganglion cells and their axon terminals in laminae I-III of the grey matter of the spinal cord, in the rabbit, cat and marmoset monkey. However, no binding was observed in either the dorsal root ganglia or spinal cord in the mouse, rat, guinea pig or flying fox. These results indicate an inter-species variation in the expression of cell-surface glycoconjugates on mammalian primary sensory neurones.

Experimental rabies in skunks: effects of immunosuppression induced by cyclophosphamide.

PubMed Central

Charlton, K M; Casey, G A; Campbell, J B

1984-01-01

Striped skunks (Mephitis mephitis) were inoculated with street rabies virus and immunosuppressed with several doses of cyclophosphamide. Control skunks were inoculated with street virus only. The skunks were killed in terminal stages of the disease and several tissues were collected for examination by immunofluorescence, light microscopy and viral titration. Sera collected at euthanasia from most of the principals did not contain detectable rabies neutralizing antibodies, whereas high titers occurred terminally in controls. Immunofluorescence was much more entensive in submandibular salivary glands of cyclophosphamide-treated than control skunks. Similarly, virus was isolated from this tissue more consistently and at higher titer from principals than from controls. Immunofluorescence was extensive in brains of all skunks (both groups), but virus was isolated consistently only from brains of cyclophosphamide-treated skunks. Most of the cyclophosphamide-treated skunks had very few inflammatory cells in brain and cerebrospinal ganglia. Neuronal degeneration occurred in dorsal root ganglia of both principals and controls. The results suggest that the immune response has no effect on the development of rabies-induced aggressive behavior, that the immune response may inhibit salivary gland infection and that it is not essential for the development of neuronal degeneration in dorsal root ganglia. PMID:6370390

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.

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.

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.

Scanning electron microscopic study of the lingual papillae in the arctic fox (Alopex lagopus L., 1758).

PubMed

Jackowiak, H; Godynicki, S; Skieresz-Szewczyk, K; Trzcielińska-Lorych, J

2009-10-01

This study aims to show the distribution and the three-dimensional structure of the lingual papillae in the arctic fox. The macro- and microscopic structure of the tongue and its lingual papillae was studied in 11 adult arctic foxes. Two types of mechanical papillae were distinguished on the dorsal surface of the tongue--filiform papillae and conical papillae. The gustatory papillae in the arctic fox are represented by fungiform, vallate and foliate papillae. The keratinized filiform papillae on the anterior part of tongue are composed of one big posterior process accompanied by 10-12 secondary anterior processes. The number of anterior processes of filiform papillae undergo a complete reduction within the area between the posterior part of the body of the tongue and area of the vallate papillae. The conical papillae cover the whole dorsal surface of the root of the tongue, including the lateral parts surrounding the area of the vallate papillae and the posterior part of the root. The size of the conical papillae increases towards the root of the tongue but their density decreases. In the arctic fox, there are three pairs of vallate papillae distributed on the plan of a triangle. The diameter of vallate papillae in each successive pair is bigger. The wall surrounding the body of the vallate papilla and its gustatory trench is composed of six to eight conical papillae joined at various degree. The foliate papillae on both margins of the tongue consist of seven to nine laminae.

ISTAR Evaluation

DTIC Science & Technology

1988-07-01

As root, create /etc/ passwd entries with names that are the same as they will be in ISTAR environment. ISTAR users: As frmadmin within the...exist in IS- TAR. Individuals must be regular UNIX users (i.e., have legal entries in /etc/ passwd and /etc/group) and have ISTAR accounts created by...maintained in /etc/ passwd and /etc/group. ISTAR infor- mation is maintained in the names of directories that represent a person and the contracts being

Osthole, a Coumadin Analog from Cnidium monnieri (L.) Cusson, Ameliorates Nucleus Pulposus-Induced Radicular Inflammatory Pain by Inhibiting the Activation of Extracellular Signal-Regulated Kinase in Rats.

PubMed

Wu, Hai-Xuan; Wang, Yi-Min; Xu, Hui; Wei, Ming; He, Qiu-Lan; Li, Mei-Na; Sun, Lai-Bao; Cao, Ming-Hui

2017-01-01

This study was aimed at assessing the role of extracellular signal regulated kinase (ERK) in mechanical allodynia resulting from lumbar disc herniation (LDH) and exploring the osthole's anti-nociceptive effect on ERK activation. Radicular pain was generated by applying nucleus pulposus (NP) to the L5 dorsal root ganglion (DRG). Allodynia was measured using Von Frey filaments to calculate the mechanical pain threshold. Phosphorylated ERK and total ERK protein in the lumbar spinal dorsal horn was detected by using the Western blot technique. Cyclooxygenase 2 (COX-2) mRNA was assessed by real-time reverse-transcription polymerase chain reaction. The application of NP to L5 DRG induced mechanical hypersensitivity which lasted for at least 28 days, and a significant increase of ERK phosphorylation in the ipsilateral spinal dorsal horn from postoperative day (POD) 1 to POD 21. ERK inhibitor attenuated NP-induced hyperalgesia compared to the dimethyl sulfoxide-(vehicle control) administered group (p < 0.05). Epidural treatment with osthole could ameliorate NP-evoked hyperalgesia by suppressing the activation of ERK rather than decreasing the expression of ERK protein. Osthole could also inhibit the increased expression of COX-2 mRNA in spinal dorsal horn, which was a known downstream effect of ERK signaling pathway. Our results suggest that ERK activation in the spinal dorsal horn plays a vital role in NP-evoked hyperalgesia. Osthole exerts analgesic effect on radicular inflammatory pain in LDH rat model, by down-regulating the mRNA expression of the target gene of COX-2 via inhibiting ERK activation in the spinal dorsal horn. © 2017 S. Karger AG, Basel.

A New Technique to Map the Lymphatic Distribution and Alignment of the Penis.

PubMed

Long, Liu Yan; Qiang, Pan Fu; Ling, Tao; Wei, Zhang Yan; Long, Zhang Yu; Shan, Meng; Rong, Li Shi; Li, Li Hong

2015-08-01

The present study was to examine the distribution of lymphatic vessels in the penis of normal adult males, which could provide an anatomical basis for improvement of incisions in penile lengthening surgery, and may also help to prevent postoperative refractory edema. Thirteen normal adult male volunteers were recruited for this study. Contrast agent was injected subcutaneously in the foreskin of the penis, and after two minutes magnetic resonance lymphangiography (MRL) was performed. The acquired magnetic resonance images were analyzed to determine the changes in the number and diameter of lymphatic vessels in different parts of the penis. Maximum intensity projections (MIP) and materializes interactive medical image control system (MIMICS) were applied to analyze the overall distribution of lymphatic vessels in the penis. Magnetic resonance imaging (MRI) showed that the lymphatic vessels were in conspicuous contrast with surrounding tissues and could be clearly identified. Penile lymphatic vessels were clearly visible in the root of the penis. At the junction of the penis and the abdominal wall, all lymphatic vessels were found to be concentrated in the dorsal part of the penis. MIP two-dimensional reconstruction showed that the overall distribution of relatively large lymphatic vessels in the dorsal and ventral parts of the penis could be seen clearly on bilateral 45° position, but not inside the abdominal wall because some of lymphatic vessels were overlapped by other tissues in the abdomen. MIMICS three-dimensional reconstruction was able to reveal the overall spatial distribution of lymphatic vessels in the penis from any angle. The reconstruction results showed that there were 1-2 main lymphatic vessels on the root of dorsal penis, which coursed along the cavernous to the first physiological curvature of the penis. Lymphatic vessels merged on both sides of the ventral penis. At the root of the penis, lymphatic vessels gradually coursed to the dorsal surface of the penis and folded at the abdominal wall to the outside, and finally merged into the inguinal lymph nodes. The changes in distribution, number and diameter of the lymphatic vessels in the penis were observed by MRI. MIP and MIMICS reconstructions directly revealed the anatomical features of penile lymphatic vessels such as spatial distribution, overall alignment, and the relations to adjacent structures, drainage and reflux. The study will provide the anatomical basis for penile surgery, penile lymphatic reflux disorders caused by trauma or lymphatic vessels obstruction, and lymph node metastasis in penile cancer. © 2014 Wiley Periodicals, Inc.

Localization and modulation of calcitonin gene-related peptide-receptor component protein-immunoreactive cells in the rat central and peripheral nervous systems.

PubMed

Ma, W; Chabot, J-G; Powell, K J; Jhamandas, K; Dickerson, I M; Quirion, R

2003-01-01

Calcitonin gene-related peptide (CGRP) is widely distributed in the central and peripheral nervous system. Its highly diverse biological activities are mediated via the G protein-coupled receptor that uniquely requires two accessory proteins for optimal function. CGRP receptor component protein (RCP) is a coupling protein necessary for CGRP-receptor signaling. In this study, we established the anatomical distribution of RCP in the rat central and peripheral nervous system and its relationship to CGRP immunoreactivity. RCP-immunoreactive (IR) perikarya are widely and selectively distributed in the cerebral cortex, septal nuclei, hippocampus, various hypothalamic nuclei, amygdala, nucleus colliculus, periaqueductal gray, parabrachial nuclei, locus coeruleus, cochlear nuclei, dorsal raphe nuclei, the solitary tractus nucleus and gracile nucleus, cerebellar cortex, various brainstem motor nuclei, the spinal dorsal and ventral horns. A sub-population of neurons in the dorsal root ganglia (DRG) and trigeminal ganglia were strongly RCP-IR. Overall, the localization of RCP-IR closely matched with that of CGRP-IR. We also determined whether RCP in DRG and dorsal horn neurons can be modulated by CGRP receptor blockade and pain-related pathological stimuli. The intrathecal injection of the antagonist CGRP(8-37) markedly increased RCP expression in the lumbar DRG and spinal dorsal horn. Carrageenan-induced plantar inflammation produced a dramatic bilateral increase in RCP expression in the dorsal horn while a partial sciatic nerve ligation reduced RCP expression in the ipsilateral superficial dorsal horn. Our data suggest that the distribution of RCP immunoreactivity is closely matched with CGRP immunoreactivity in most of central and peripheral nervous systems. The co-localization of RCP and CGRP in motoneurons and primary sensory neurons suggests that CGRP has an autocrine or paracrine effect on these neurons. Moreover, our data also suggest that RCP expression in DRG and spinal cord can be modulated during CGRP receptor blockade, inflammation or neuropathic pain and this CGRP receptor-associated protein is dynamically regulated.

Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful.

PubMed

Ryana, Haneet Kour; Srinath, Rashmi; Prakash, Shobha

2016-06-01

Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes.

Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful

PubMed Central

Srinath, Rashmi; Prakash, Shobha

2016-01-01

Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes. PMID:27504421

A human trial of HSV mediated gene transfer for the treatment of chronic pain

PubMed Central

Wolfe, Darren; Mata, Marina; Fink, David J.

2009-01-01

Gene transfer to the dorsal root ganglion using replication defective herpes simplex virus (HSV)-based vectors reduces pain related behaviors in rodent models of inflammatory pain, neuropathic pain, and pain caused by cancer in bone. HSV vectors engineered to produce inhibitory neurotransmitters including the delta opioid agonist peptide enkephalin, the mu opioid agonist peptide endomorphin-2 and glutamic acid decarboxylase (GAD) to effect the release of gamma amino butyric acid (GABA) act to inhibit nociceptive neurotransmission at the first synapse between primary nociceptive and second-order neuron in the dorsal horn of spinal cord. HSV vectors engineered to release anti-inflammatory peptides including interleukin (IL)-4, IL-10 and the p55 soluble tumor necrosis factor α (TNFα) receptor reduce neuroimmune activation in the spinal dorsal horn. The path leading from preclinical animal studies to the ongoing phase 1 human trial of the enkephalin-producing vector in patients with pain from cancer, and plans for an efficacy trial with an opioid producing vector in inflammatory pain and an efficacy trial with a GAD producing vector in diabetic neuropathic pain are outlined. PMID:19242524

Implications and mechanism of action of gabapentin in neuropathic pain.

PubMed

Kukkar, Ankesh; Bali, Anjana; Singh, Nirmal; Jaggi, Amteshwar Singh

2013-03-01

Gabapentin is an anti-epileptic agent but now it is also recommended as first line agent in neuropathic pain, particularly in diabetic neuropathy and post herpetic neuralgia. α2δ-1, an auxillary subunit of voltage gated calcium channels, has been documented as its main target and its specific binding to this subunit is described to produce different actions responsible for pain attenuation. The binding to α2δ-1 subunits inhibits nerve injury-induced trafficking of α1 pore forming units of calcium channels (particularly N-type) from cytoplasm to plasma membrane (membrane trafficking) of pre-synaptic terminals of dorsal root ganglion (DRG) neurons and dorsal horn neurons. Furthermore, the axoplasmic transport of α2δ-1 subunits from DRG to dorsal horns neurons in the form of anterograde trafficking is also inhibited in response to gabapentin administration. Gabapentin has also been shown to induce modulate other targets including transient receptor potential channels, NMDA receptors, protein kinase C and inflammatory cytokines. It may also act on supra-spinal region to stimulate noradrenaline mediated descending inhibition, which contributes to its anti-hypersensitivity action in neuropathic pain.

Peripheral Opioid Analgesia

DTIC Science & Technology

1999-07-16

central nervous system by neurons called primary afferent nociceptors (PANs). These neurons have their cell bodies in the dorsal root ganglia (ORG... neurons , and in particular their role in the generation, propagation and modulation of noxious stimulation will be summarized. The final section of...and processing of each opioid peptide is discussed below. The human POMC gene is 7665 base pairs (bp) long which contains three exons and two

Pulsed Radiofrequency to the Dorsal Root Ganglion in Acute Herpes Zoster and Postherpetic Neuralgia.

PubMed

Kim, Koohyun; Jo, Daehyun; Kim, EungDon

2017-03-01

Latent varicella zoster virus reactivates mainly in sensory ganglia such as the dorsal root ganglion (DRG) or trigeminal ganglion. The DRG contains many receptor channels and is an important region for pain signal transduction. Sustained abnormal electrical activity to the spinal cord via the DRG in acute herpes zoster can result in neuropathic conditions such as postherpetic neuralgia (PHN). Although the efficacy of pulsed radiofrequency (PRF) application to the DRG in various pain conditions has been previously reported, the application of PRF to the DRG in patients with herpes zoster has not yet been studied. The aim of the present study was to compare the clinical effects of PRF to the DRG in patients with herpes zoster to those of PRF to the DRG in patients with PHN. Retrospective comparative study. University hospital pain center in Korea. The medical records of 58 patients who underwent PRF to the DRG due to zoster related pain (herpes zoster or PHN) were retrospectively analyzed. Patients were divided into 2 groups according to the timing of PRF after zoster onset: an early PRF group (within 90 days) and a PHN PRF group (more than 90 days). The efficacy of PRF was assessed by a numeric rating scale (NRS) and by recording patient medication doses before PRF and at one week, 4 weeks, 8 weeks, and 12 weeks after PRF. Pain intensity was decreased after PRF in all participants. However, the degree of pain reduction was significantly higher in the early PRF group. Moreover, more patients discontinued their medication in the early PRF group, and the PRF success rate was also higher in the early PRF group. The relatively small sample size from a single center, short duration of review of medical records, and the retrospective nature of the study. PRF to the DRG is a useful treatment for treatment-resistant cases of herpes zoster and PHN. Particularly in herpes zoster patients with intractable pain, application of PRF to the DRG should be considered for pain control and prevention of PHN.Key words: Pulsed radiofrequency, dorsal root ganglion, herpes zoster, postherpetic neuralgia.

Bromodomain-containing Protein 4 Activates Voltage-gated Sodium Channel 1.7 Transcription in Dorsal Root Ganglia Neurons to Mediate Thermal Hyperalgesia in Rats.

PubMed

Hsieh, Ming-Chun; Ho, Yu-Cheng; Lai, Cheng-Yuan; Wang, Hsueh-Hsiao; Lee, An-Sheng; Cheng, Jen-Kun; Chau, Yat-Pang; Peng, Hsien-Yu

2017-11-01

Bromodomain-containing protein 4 binds acetylated promoter histones and promotes transcription; however, the role of bromodomain-containing protein 4 in inflammatory hyperalgesia remains unclear. Male Sprague-Dawley rats received hind paw injections of complete Freund's adjuvant to induce hyperalgesia. The dorsal root ganglia were examined to detect changes in bromodomain-containing protein 4 expression and the activation of genes involved in the expression of voltage-gated sodium channel 1.7, which is a key pain-related ion channel. The intraplantar complete Freund's adjuvant injections resulted in thermal hyperalgesia (4.0 ± 1.5 s; n = 7). The immunohistochemistry and immunoblotting results demonstrated an increase in the bromodomain-containing protein 4-expressing dorsal root ganglia neurons (3.78 ± 0.38 fold; n = 7) and bromodomain-containing protein 4 protein levels (2.62 ± 0.39 fold; n = 6). After the complete Freund's adjuvant injection, histone H3 protein acetylation was enhanced in the voltage-gated sodium channel 1.7 promoter, and cyclin-dependent kinase 9 and phosphorylation of RNA polymerase II were recruited to this area. Furthermore, the voltage-gated sodium channel 1.7-mediated currents were enhanced in neurons of the complete Freund's adjuvant rats (55 ± 11 vs. 19 ± 9 pA/pF; n = 4 to 6 neurons). Using bromodomain-containing protein 4-targeted antisense small interfering RNA to the complete Freund's adjuvant-treated rats, the authors demonstrated a reduction in the expression of bromodomain-containing protein 4 (0.68 ± 0.16 fold; n = 7), a reduction in thermal hyperalgesia (7.5 ± 1.5 s; n = 7), and a reduction in the increased voltage-gated sodium channel 1.7 currents (21 ± 4 pA/pF; n = 4 to 6 neurons). Complete Freund's adjuvant triggers enhanced bromodomain-containing protein 4 expression, ultimately leading to the enhanced excitability of nociceptive neurons and thermal hyperalgesia. This effect is likely mediated by the enhanced expression of voltage-gated sodium channel 1.7.

Gibberellins Interfere with Symbiosis Signaling and Gene Expression and Alter Colonization by Arbuscular Mycorrhizal Fungi in Lotus japonicus1

PubMed Central

Takeda, Naoya; Handa, Yoshihiro; Tsuzuki, Syusaku; Kojima, Mikiko; Sakakibara, Hitoshi; Kawaguchi, Masayoshi

2015-01-01

Arbuscular mycorrhiza is a mutualistic plant-fungus interaction that confers great advantages for plant growth. Arbuscular mycorrhizal (AM) fungi enter the host root and form symbiotic structures that facilitate nutrient supplies between the symbionts. The gibberellins (GAs) are phytohormones known to inhibit AM fungal infection. However, our transcriptome analysis and phytohormone quantification revealed GA accumulation in the roots of Lotus japonicus infected with AM fungi, suggesting that de novo GA synthesis plays a role in arbuscular mycorrhiza development. We found pleiotropic effects of GAs on the AM fungal infection. In particular, the morphology of AM fungal colonization was drastically altered by the status of GA signaling in the host root. Exogenous GA treatment inhibited AM hyphal entry into the host root and suppressed the expression of Reduced Arbuscular Mycorrhization1 (RAM1) and RAM2 homologs that function in hyphal entry and arbuscule formation. On the other hand, inhibition of GA biosynthesis or suppression of GA signaling also affected arbuscular mycorrhiza development in the host root. Low-GA conditions suppressed arbuscular mycorrhiza-induced subtilisin-like serine protease1 (SbtM1) expression that is required for AM fungal colonization and reduced hyphal branching in the host root. The reduced hyphal branching and SbtM1 expression caused by the inhibition of GA biosynthesis were recovered by GA treatment, supporting the theory that insufficient GA signaling causes the inhibitory effects on arbuscular mycorrhiza development. Most studies have focused on the negative role of GA signaling, whereas our study demonstrates that GA signaling also positively interacts with symbiotic responses and promotes AM colonization of the host root. PMID:25527715

Gibberellins interfere with symbiosis signaling and gene expression and alter colonization by arbuscular mycorrhizal fungi in Lotus japonicus.

PubMed

Takeda, Naoya; Handa, Yoshihiro; Tsuzuki, Syusaku; Kojima, Mikiko; Sakakibara, Hitoshi; Kawaguchi, Masayoshi

2015-02-01

Arbuscular mycorrhiza is a mutualistic plant-fungus interaction that confers great advantages for plant growth. Arbuscular mycorrhizal (AM) fungi enter the host root and form symbiotic structures that facilitate nutrient supplies between the symbionts. The gibberellins (GAs) are phytohormones known to inhibit AM fungal infection. However, our transcriptome analysis and phytohormone quantification revealed GA accumulation in the roots of Lotus japonicus infected with AM fungi, suggesting that de novo GA synthesis plays a role in arbuscular mycorrhiza development. We found pleiotropic effects of GAs on the AM fungal infection. In particular, the morphology of AM fungal colonization was drastically altered by the status of GA signaling in the host root. Exogenous GA treatment inhibited AM hyphal entry into the host root and suppressed the expression of Reduced Arbuscular Mycorrhization1 (RAM1) and RAM2 homologs that function in hyphal entry and arbuscule formation. On the other hand, inhibition of GA biosynthesis or suppression of GA signaling also affected arbuscular mycorrhiza development in the host root. Low-GA conditions suppressed arbuscular mycorrhiza-induced subtilisin-like serine protease1 (SbtM1) expression that is required for AM fungal colonization and reduced hyphal branching in the host root. The reduced hyphal branching and SbtM1 expression caused by the inhibition of GA biosynthesis were recovered by GA treatment, supporting the theory that insufficient GA signaling causes the inhibitory effects on arbuscular mycorrhiza development. Most studies have focused on the negative role of GA signaling, whereas our study demonstrates that GA signaling also positively interacts with symbiotic responses and promotes AM colonization of the host root. © 2015 American Society of Plant Biologists. All Rights Reserved.

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

Presynaptic and postsynaptic effects of local cathodal DC polarization within the spinal cord in anaesthetized animal preparations

PubMed Central

Bolzoni, F; Jankowska, E

2015-01-01

The present study aimed to compare presynaptic and postsynaptic actions of direct current polarization in the spinal cord, focusing on DC effects on primary afferents and motoneurons. To reduce the directly affected spinal cord region, a weak polarizing direct current (0.1–0.3 μA) was applied locally in deeply anaesthetized cats and rats; within the hindlimb motor nuclei in the caudal lumbar segments, or in the dorsal horn within the terminal projection area of low threshold skin afferents. Changes in the excitability of primary afferents activated by intraspinal stimuli (20–50 μA) were estimated using increases or decreases in compound action potentials recorded from the dorsal roots or peripheral nerves as their measure. Changes in the postsynaptic actions of the afferents were assessed from intracellularly recorded monosynaptic EPSPs in hindlimb motoneurons and monosynaptic extracellular field potentials (evoked by group Ia afferents in motor nuclei, or by low threshold cutaneous afferents in the dorsal horn). The excitability of motoneurons activated by intraspinal stimuli was assessed using intracellular records or motoneuronal discharges recorded from a ventral root or a muscle nerve. Cathodal polarization was found to affect motoneurons and afferents providing input to them to a different extent. The excitability of both was markedly increased during DC application, although post-polarization facilitation was found to involve presynaptic afferents and some of their postsynaptic actions, but only negligibly motoneurons themselves. Taken together, these results indicate that long-lasting post-polarization facilitation of spinal activity induced by locally applied cathodal current primarily reflects the facilitation of synaptic transmission. PMID:25416625

Inhibition of the Rho/ROCK pathway prevents neuronal degeneration in vitro and in vivo following methylmercury exposure

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

Fujimura, Masatake, E-mail: fujimura@nimd.go.jp; Usuki, Fusako; Kawamura, Miwako

Methylmercury (MeHg) is an environmental neurotoxicant which induces neuropathological changes in both the central nervous and peripheral sensory nervous systems. Our recent study demonstrated that down-regulation of Ras-related C3 botulinum toxin substrate 1 (Rac1), which is known to promote neuritic extension, preceded MeHg-induced damage in cultured cortical neurons, suggesting that MeHg-mediated axonal degeneration is due to the disturbance of neuritic extension. Therefore we hypothesized that MeHg-induced axonal degeneration might be caused by neuritic extension/retraction incoordination. This idea brought our attention to the Ras homolog gene (Rho)/Rho-associated coiled coil-forming protein kinase (ROCK) pathway because it has been known to be associatedmore » with the development of axon and apoptotic neuronal cell death. Here we show that inhibition of the Rho/ROCK pathway prevents MeHg-intoxication both in vitro and in vivo. A Rho inhibitor, C3 toxin, and 2 ROCK inhibitors, Fasudil and Y-27632, significantly protected against MeHg-induced axonal degeneration and apoptotic neuronal cell death in cultured cortical neuronal cells exposed to 100 nM MeHg for 3 days. Furthermore, Fasudil partially prevented the loss of large pale neurons in dorsal root ganglia, axonal degeneration in dorsal spinal root nerves, and vacuolar degeneration in the dorsal columns of the spinal cord in MeHg-intoxicated model rats (20 ppm MeHg in drinking water for 28 days). Hind limb crossing sign, a characteristic MeHg-intoxicated sign, was significantly suppressed in this model. The results suggest that inhibition of the Rho/ROCK pathway rescues MeHg-mediated neuritic extension/retraction incoordination and is effective for the prevention of MeHg-induced axonal degeneration and apoptotic neuronal cell death.« less

Protease-activated receptor 2 in dorsal root ganglion contributes to peripheral sensitization of bone cancer pain.

PubMed

Liu, S; Liu, Y-P; Yue, D-M; Liu, G-J

2014-03-01

Treating bone cancer pain continues to be a major clinical challenge, and the underlying mechanisms of bone cancer pain remain elusive. Protease-activated receptor 2 (PAR2) has been reported to be involved in neurogenic inflammation, nociceptive pain and hyperalgesia. Here, we investigated the role of PAR2 in bone cancer pain development. Expression of PAR2, mechanical allodynia, thermal hyperalgesia and neurochemical alterations induced by bone cancer pain were analysed in male, adult C3H/HeJ mice with tumour cell implantation (TCI). To investigate the contribution of PAR2 to bone cancer pain, PAR2 antagonist peptide and PAR2 knockout mice were used. TCI produced bone cancer-related pain behaviours. Production and persistence of these pain behaviours were well correlated with TCI-induced up-regulation of PAR2 in sciatic nerve and dorsal root ganglia (DRG). PAR2 knockout and spinal administration of PAR2 antagonist peptide prevented and/or reversed bone cancer-related pain behaviours and associated neurochemical changes in DRG and dorsal horn (DH). TCI also induced proteases release in tumour-bearing tibia, sciatic nerve and DRG. Plantar injection of supernatant from sarcoma cells induced PAR2 up-regulation and intracellular calcium [Ca(2+) ]i increase in DRG, and calcitonin gene-related peptide accumulation in DH, as well as significant thermal and mechanical hyperalgesia, which were all in PAR2-dependent manners. These findings suggest that PAR2 may be a key mediator for peripheral sensitization of bone cancer pain. Inhibiting PAR2 activation, especially during the early phase, may be a new therapy for preventing/suppressing development of bone cancer pain. © 2013 European Pain Federation - EFIC®

Nogo-66 Receptor Antagonist Peptide (NEP1-40) Administration Promotes Functional Recovery and Axonal Growth After Lateral Funiculus Injury in the Adult Rat

PubMed Central

Cao, Y.; Shumsky, J. S.; Sabol, M. A.; Kushner, R. A.; Strittmatter, S.; Hamers, F. P. T.; Lee, D. H. S.; Rabacchi, S. A.; Murray, M.

2010-01-01

Objective The myelin protein Nogo inhibits axon regeneration by binding to its receptor (NgR) on axons. Intrathecal delivery of an NgR antagonist (NEP1-40) promotes growth of injured corticospinal axons and recovery of motor function following a dorsal hemisection. The authors used a similar design to examine recovery and repair after a lesion that interrupts the rubrospinal tract (RST). Methods Rats received a lateral funiculotomy at C4 and NEP1-40 or vehicle was delivered to the cervical spinal cord for 4 weeks. Outcome measures included motor and sensory tests and immunohistochemistry. Results Gait analysis showed recovery in the NEP1-40-treated group compared to operated controls, and a test of forelimb usage also showed a beneficial effect. The density of labeled RST axons increased ipsilaterally in the NEP1-40 group in the lateral funiculus rostral to the lesion and contralaterally in both gray and white matter. Thus, rubrospinal axons exhibited diminished dieback and/or growth up to the lesion site. This was accompanied by greater density of 5 HT and calcitonin gene-related peptide axons adjacent to and into the lesion/matrix site in the NEP1-40 group. Conclusions NgR blockade after RST injury is associated with axonal growth and/or diminished dieback of severed RST axons up to but not into or beyond the lesion/matrix site, and growth of serotonergic and dorsal root axons adjacent to and into the lesion/matrix site. NgR blockade also supported partial recovery of function. The authors’ results indicate that severed rubrospinal axons respond to NEP1-40 treatment but less robustly than corticospinal, raphe-spinal, or dorsal root axons. PMID:18056009

Src family kinases mediate the inhibition of substance P release in the rat spinal cord by μ-opioid receptors and GABAB receptors, but not α2 adrenergic receptors

PubMed Central

Zhang, Guohua; Chen, Wenling; Marvizón, Juan Carlos G.

2010-01-01

GABAB, μ-opioid, and adrenergic α2 receptors inhibit substance P release from primary afferent terminals in the dorsal horn. Studies in cell expression systems suggest that μ-opioid and GABAB receptors inhibit transmitter release from primary afferents by activating Src family kinases (SFKs), which then phosphorylate and inhibit voltage-gated calcium channels. This study investigated whether SFKs mediate the inhibition of substance P release by these three receptors. Substance P release was measured as neurokinin 1 receptor (NK1R) internalization in spinal cord slices and in vivo. In slices, NK1R internalization induced by high frequency dorsal root stimulation was inhibited by the μ-opioid agonist DAMGO and the GABAB agonist baclofen. This inhibition was reversed by the SFK inhibitor PP1. NK1R internalization induced by low frequency stimulation was also inhibited by DAMGO, but PP1 did not reverse this effect. In vivo, NK1R internalization induced by noxious mechanical stimulation of the hind paw was inhibited by intrathecal DAMGO and baclofen. This inhibition was reversed by intrathecal PP1, but not by the inactive PP1 analog PP3. PP1 produced no effect by itself. The α2 adrenergic agonists medetomidine and guanfacine produced a small but statistically significant inhibition of NK1R internalization induced by low frequency dorsal root stimulation. PP1 did not reverse the inhibition by guanfacine. These results show that SFKs mediate the inhibition of substance P release by μ-opioid and GABAB receptors, but not by α2 receptors, which is probably mediated by the binding of G protein βγ subunits to calcium channels. PMID:20726886

Intrathecal morphine for analgesia in children undergoing selective dorsal rhizotomy.

PubMed

Dews, T E; Schubert, A; Fried, A; Ebrahim, Z; Oswalt, K; Paranandi, L

1996-03-01

Selective dorsal root rhizotomy is performed for relief of spasticity in children with cerebral palsy. Postoperative pain relief can be provided by intrathecal morphine administered at the time of the procedure. We sought to define an optimal dose of intrathecal morphine in children undergoing selective rhizotomy, through a randomized, double-blinded prospective trial. After institutional approval and parental written informed consent, 27 patients, ages 3-10 years, were randomized to receive 10, 20, or 30 micrograms.kg-1 (Groups A, B, and C, respectively) of preservative-free morphine administered intrathecally by the surgeon after dural closure. Postoperatively, vital signs, pulse oximetry, and pain intensity scores were recorded hourly for 24 hr. Supplemental intravenous morphine was administered postoperatively according to a predetermined schedule based on pain scores. There was considerable individual variability in the time to initial morphine dosing and cumulative supplemental morphine dose. Time to first supplemental morphine dose was not different between groups. When compared to Groups A and B, cumulative 6-hr supplemental morphine dose was significantly lower in Group C (38.6 +/- 47 micrograms versus 79.1 +/- 74 and 189.6 +/- 126 for Groups A and B, respectively). By 12 hr, cumulative supplemental morphine dose was similar in Groups A and C. Group B consistently had a higher supplemental dose requirement than Groups A and C at 6, 12, and 18 hr. By 24 hr, there was no difference in cumulative dose among groups. Postoperative pain scores and the incidence of respiratory events, nausea, vomiting and pruritus were comparable among groups. These data suggest that intrathecal morphine at 30 micrograms.kg-1 provides the most intense analgesia at 6 hr following selective dorsal root rhizotomy, but was otherwise comparable to the 10 micrograms.kg-1 dose.

Upregulation of adrenomedullin in the spinal cord and dorsal root ganglia in the early phase of CFA-induced inflammation in rats.

PubMed

Hong, Yanguo; Liu, Yushan; Chabot, Jean-Guy; Fournier, Alain; Quirion, Rémi

2009-11-01

Adrenomedullin (AM), a member of calcitonin gene-related peptide (CGRP) family, has been demonstrated to be a pronociceptive mediator [28]. This study was undertaken to investigate the role of AM in a model of complete Freund's adjuvant (CFA)-induced inflammatory pain. Injection of CFA, but not of saline, in the unilateral hindpaw produced an increase in the expression of AM-like immunoreactivity (AM-IR) in laminae I-II of the spinal cord as well as in small- and medium-sized dorsal root ganglion (DRG) neurons at 48 h. The content of AM in DRG on the side ipsilateral to CFA injection started to increase at 4 h and remained at high levels at 24 and 48 h. The selective antagonist of AM receptors, AM(22-52), administered intrathecally (i.t.) 24 h after CFA injection inhibited inflammation-associated hyperalgesia in a dose-dependent manner (2, 5 and 10 nmol). Impressively, this anti-hyperalgesic effect lasted for at least 24 h. I.t. administration of AM(22-52) (10 nmol) also reversed CFA-induced increase in AM-IR in the spinal dorsal horn and DRG. Furthermore, blockade of AM receptors abolished CFA-induced changes in the expression and content of CGRP-like immunoreactivity in these regions. Taken together, our results suggest that the upregulation of AM in DRG neurons contributes to the development of inflammatory pain, and this effect is mediated, at least in part, by enhancing the expression and release of CGRP. Blocking AM receptor downstream signaling effects using antagonists has the potential of relieving pain following the induction of inflammation.

Characterization of a chondroitin sulfate hydrogel for nerve root regeneration

NASA Astrophysics Data System (ADS)

Conovaloff, Aaron; Panitch, Alyssa

2011-10-01

Brachial plexus injury is a serious medical problem that affects many patients annually, with most cases involving damage to the nerve roots. Therefore, a chondroitin sulfate hydrogel was designed to both serve as a scaffold for regenerating root neurons and deliver neurotrophic signals. Capillary electrophoresis showed that chondroitin sulfate has a dissociation constant in the micromolar range with several common neurotrophins, and this was determined to be approximately tenfold stronger than with heparin. It was also revealed that nerve growth factor exhibits a slightly stronger affinity for hyaluronic acid than for chondroitin sulfate. However, E8 chick dorsal root ganglia cultured in the presence of nerve growth factor revealed that ganglia cultured in chondroitin sulfate scaffolds showed more robust growth than those cultured in control gels of hyaluronic acid. It is hypothesized that, despite the stronger affinity of nerve growth factor for hyaluronic acid, chondroitin sulfate serves as a better scaffold for neurite outgrowth, possibly due to inhibition of growth by hyaluronic acid chains.

Pain and brachial plexus lesions: evaluation of initial outcomes after reconstructive microsurgery and validation of a new pain severity scale.

PubMed

Bonilla, Gonzalo; Di Masi, Gilda; Battaglia, Danilo; Otero, José María; Socolovsky, Mariano

2011-01-01

Peripheral nerve lesions usually are associated with neuropathic pain. In the present paper, we describe a simple scale to quantify pain after brachial plexus injuries and apply this scale to a series of patients to determine initial outcomes after reconstructive surgery. Fifty-one patients with traumatic brachial plexus avulsion injuries were treated over the period of one calendar year at one center by the same surgical team. Of these, 28 patients who were available for follow-up reported some degree of neuropathic pain radiating towards the hand or forearm and underwent reconstructive microsurgery and direct pain management, including trunk and nerve neurolysis and repair. A special pain severity rating scale was developed and used to assess patients' pain before and after surgery, over a minimum follow-up of 6 months. An independent researcher, not part of the surgical team, performed all pre- and postoperative evaluations. Of the 28 patients with brachial plexus traction injuries who met eligibility criteria, 93% were male, and most were young (mean age, 27.6 years). The mean preoperative severity of pain using our scale was 30.9 out of a maximum of 37 (± 0.76 SD), which fell to a mean of 6.9 (± 0.68 SD) 6 months post-procedure. On average, pain declined by 78% across the whole series, a decline that was statistically significant (p < .001). Subset analysis revealed similar improvements across all the different parameters of pain. We have designed and tested a simple and reliable method by which to quantify neuropathic pain after traumatic brachial plexus injuries. Initial surgical treatment of the paralysis--including nerve, trunk and root reconstruction, and neurolysis--comprises an effective means by which to initially treat neuropathic pain. Ablative or neuromodulative procedures, like dorsal root entry zone, should be reserved for refractory cases.

Identification of interleukin-1 beta as a key mediator in the upregulation of Cav3.2–USP5 interactions in the pain pathway

PubMed Central

Stemkowski, Patrick L; Garcia-Caballero, Agustin; Gadotti, Vinicius M; M’Dahoma, Said; Chen, Lina; Souza, Ivana A

2017-01-01

We recently reported that nerve injury or peripheral inflammation triggers an upregulation of the deubiquitinase, USP5 in mouse dorsal root ganglion and spinal dorsal horn. This leads to dysregulated ubiquitination of Cav3.2 T-type calcium channels, thus increasing Cav3.2 channel plasma membrane expression and nociceptive signaling in the primary afferent pain pathway. This phenomenon could be recapitulated by noninvasive, optogenetic activation of transient receptor potential vanilloid-1–expressing nociceptors, indicating that neuronal activity is a key player in this process. Given the relevance of the pro-inflammatory cytokine interleukin-1 beta in many forms of pathological pain, we hypothesized that interleukin-1 beta may be a critical cofactor required to drive upregulation of interactions between USP5 and Cav3.2 channels. Here, we report that gene expression, as well as protein levels for interleukin-1 beta and the endogenous interleukin-1 receptor-I antagonist, IL-1Ra are unaltered following conditioning stimulation of optogenetically targeted cutaneous nociceptors, indicating that neuronal activity is not a driver of interleukin-1 beta signaling. In contrast, co-immunoprecipitation experiments revealed that intrathecal administration of interleukin-1 beta in wild-type mice led to an increase in the interaction between USP5 and Cav3.2 in the spinal dorsal horn. Moreover, disruption of the interaction between USP5 and Cav3.2 with TAT peptides suppressed acute nocifensive responses produced by interleukin-1 beta, which was similar to that achieved by elimination of T-type channel activity with the channel blockers, mibefradil, or TTA-A2. Finally, this upregulation could be maintained in dorsal root ganglion neuron cultures exposed overnight to interleukin-1 beta, while the copresence of interleukin-1 receptor antagonist or the dampening of neuronal cell activity with tetrodotoxin attenuated this response. Altogether, our findings identify interleukin-1 beta as an upstream trigger for the upregulation of interactions between USP5 and Cav3.2 channels in the pain pathway, presumably by triggering increased firing activity in afferent fibers. PMID:28741432

[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).

Changes of cervical dorsal root ganglia induced by compression injury and decompression procedure: a novel rat model of cervical radiculoneuropathy.

PubMed

Tang, Zhan-Ying; Shu, Bing; Cui, Xue-Jun; Zhou, Chong-Jian; Shi, Qi; Holz, Jonathan; Wang, Yong-Jun

2009-02-11

Our study aimed to establish a model of compression injury of cervical dorsal root ganglia (DRG) in the rat and to investigate the pathological changes following compression injury and decompression procedures. Thirty rats were divided into three groups: control group receiving sham surgery, compression group undergoing surgery to place a micro-silica gel on C6 DRG, and decompression group with subsequent decompression procedure. The samples harvested from the different groups were examined with light microscopy, ultrastructural analysis, and horseradish peroxidase (HRP) retrograde tracing techniques. Apoptosis of DRG neurons was demonstrated with TUNEL staining. Changes in PGE2 and PLA2 in DRG neurons were detected with enzyme-linked immunosorbent assay (ELISA). Local expression of vascular endothelial growth factor (VEGF) was monitored with immunohistochemistry. DRG neurons in the compression group became swollen with vacuolar changes in cytoplasm. Decompression procedure partially ameliorated the resultant compression pathology. Ultrastructural examination showed a large number of swollen vacuoles, demyelinated nerve root fibers, absence of Schwann cells, and proliferation in the surrounding connective tissues in the compression group. Compared to the control group, the compression group showed a significant decrease in the number of the HRP-labeled cells and a significant increase in levels of PGE2 and PLA2, in the expression of VEGF protein, and in the number of apoptotic DRG neurons. These findings demonstrate that compression results in local inflammation, followed by increased apoptosis and upregulation of VEGF. We conclude that such a model provides a tool to study the pathogenesis and treatment of cervical radiculoneuropathy.

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.

Bone mesenchymal stem cells attenuate radicular pain by inhibiting microglial activation in a rat noncompressive disk herniation model.

PubMed

Huang, Xiaodong; Wang, Weiheng; Liu, Xilin; Xi, Yanhai; Yu, Jiangming; Yang, Xiangqun; Ye, Xiaojian

2018-06-01

Spinal disk herniation can induce radicular pain through chemical irritation caused by proinflammatory and immune responses. Bone marrow mesenchymal stem cells (BMSCs) are a unique type of adult stem cell with the functions of suppressing inflammation and modulating immune responses. This study was undertaken to observe the effect of intrathecal BMSCs on the treatment of mechanical allodynia and the suppression of microglial activation in a rat noncompressive disk herniation model. The model was induced by the application of nucleus pulposus (NP) to the L5 dorsal root ganglion (DRG). The study found that the use of NP in the DRG can induce abnormal mechanical pain, increase the contents of the proinflammatory factors TNF-α and IL-1β, decrease the content of the anti-inflammatory cytokine TGF-β1 and activate microglia in the spinal dorsal horns (L5) (P < 0.05). BMSC administration could increase the mechanical withdrawal thresholds dramatically, decrease the contents of IL-1β and TNF-α, increase the content of TGF-β1 significantly (P < 0.05) and inhibit microglial activation in the bilateral spinal dorsal horn. Our results indicate that BMSC administration can reduce mechanical allodynia and downregulate the expression of proinflammatory cytokines by inhibiting microglial activation in the spinal dorsal horn in a rat noncompressive disk herniation model.

[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 dorsal root ganglion and human pancreatic cancer cell line is successfully established in this study. This MIA PaCa-2/DRG co-culture system demonstrates that the neural-pancreatic carcinoma cell interaction is a mutually beneficial process for the growth of neurites and pancreatic carcinoma cells. The pancreatic cancer cells show a trend of migrating to the DRG along the neurite outgrowth.

Inflammatory Pain Reduces C Fiber Activity-Dependent Slowing in a Sex-Dependent Manner, Amplifying Nociceptive Input to the Spinal Cord.

PubMed

Dickie, Allen C; McCormick, Barry; Lukito, Veny; Wilson, Kirsten L; Torsney, Carole

2017-07-05

C fibers display activity-dependent slowing (ADS), whereby repetitive stimulation (≥1 Hz) results in a progressive slowing of action potential conduction velocity, which manifests as a progressive increase in response latency. However, the impact of ADS on spinal pain processing has not been explored, nor whether ADS is altered in inflammatory pain conditions. To investigate, compound action potentials were made, from dorsal roots isolated from rats with or without complete Freund's adjuvant (CFA) hindpaw inflammation, in response to electrical stimulus trains. CFA inflammation significantly reduced C fiber ADS at 1 and 2 Hz stimulation rates. Whole-cell patch-clamp recordings in the spinal cord slice preparation with attached dorsal roots also demonstrated that CFA inflammation reduced ADS in the monosynaptic C fiber input to lamina I neurokinin 1 receptor-expressing neurons (1-10 Hz stimulus trains) without altering the incidence of synaptic response failures. When analyzed by sex, it was revealed that females display a more pronounced ADS that is reduced by CFA inflammation to a level comparable with males. Cumulative ventral root potentials evoked by long and short dorsal root stimulation lengths, to maximize and minimize the impact of ADS, respectively, demonstrated that reducing ADS facilitates spinal summation, and this was also sex dependent. This finding correlated with the behavioral observation of increased noxious thermal thresholds and enhanced inflammatory thermal hypersensitivity in females. We propose that sex/inflammation-dependent regulation of C fiber ADS can, by controlling the temporal relay of nociceptive inputs, influence the spinal summation of nociceptive signals contributing to sex/inflammation-dependent differences in pain sensitivity. SIGNIFICANCE STATEMENT The intensity of a noxious stimulus is encoded by the frequency of action potentials relayed by nociceptive C fibers to the spinal cord. C fibers conduct successive action potentials at progressively slower speeds, but the impact of this activity-dependent slowing (ADS) is unknown. Here we demonstrate that ADS is more prevalent in females than males and is reduced in an inflammatory pain model in females only. We also demonstrate a progressive delay of C fiber monosynaptic transmission to the spinal cord that is similarly sex and inflammation dependent. Experimentally manipulating ADS strongly influences spinal summation consistent with sex differences in behavioral pain thresholds. This suggests that ADS provides a peripheral mechanism that can regulate spinal nociceptive processing and pain sensation. Copyright © 2017 Dickie et al.

Axon-Sorting Multifunctional Nerve Guides: Accelerating Restoration of Nerve Function

DTIC Science & Technology

2014-10-01

factor (singly & in selected combinations) in the organotypic model system for preferential sensory or motor axon extension. Use confocal microscopy to...track axon extension of labeled sensory or motor neurons from spinal cord slices (motor) or dorsal root ganglia ( DRG ) (sensory). 20 Thy1-YFP mice...RESEARCH ACCOMPLISHMENTS: • Established a system of color-coded mixed nerve tracking using GFP and RFP expressing motor and sensory neurons (Figure 1

A Functional High-Throughput Assay of Myelination in Vitro

DTIC Science & Technology

2014-07-01

iPS cells derived from human astrocytes. These cell lines will serve as an excellent source of human cells from which our model systems may be...image the 3D rat dorsal root ganglion ( DRG ) cultures with sufficiently low background as to detect electrically-evoked depolarization events, as...stimulation and recording system specifically for this purpose. Further, we found that the limitations inherent in optimizing speed and FOV may

European Science Notes, Volume 41, Number 1.

DTIC Science & Technology

1987-01-01

extract which also *body, HNKI, stains dorsal root ganglion exhibited a trophic effect could be re- (DRG) cells and is selective for neural placed by... effect on central as well as peripheral to migrate just after the neural tube neurons. closes and that these cells migrate Neuronal Development...viscous effects which are ex- tions used pseudounsteady, cell -centered cluded from the computation-. In some finite volume methods. Quite different

A SCN10A SNP biases human pain sensitivity

PubMed Central

Duan, Guangyou; Han, Chongyang; Wang, Qingli; Guo, Shanna; Zhang, Yuhao; Ying, Ying; Huang, Penghao; Zhang, Li; Macala, Lawrence; Shah, Palak; Zhang, Mi; Li, Ningbo; Dib-Hajj, Sulayman D; Zhang, Xianwei

2016-01-01

Background: Nav1.8 sodium channels, encoded by SCN10A, are preferentially expressed in nociceptive neurons and play an important role in human pain. Although rare gain-of-function variants in SCN10A have been identified in individuals with painful peripheral neuropathies, whether more common variants in SCN10A can have an effect at the channel level and at the dorsal root ganglion, neuronal level leading to a pain disorder or an altered normal pain threshold has not been determined. Results: Candidate single nucleotide polymorphism association approach together with experimental pain testing in human subjects was used to explore possible common SCN10A missense variants that might affect human pain sensitivity. We demonstrated an association between rs6795970 (G > A; p.Ala1073Val) and higher thresholds for mechanical pain in a discovery cohort (496 subjects) and confirmed it in a larger replication cohort (1005 female subjects). Functional assessments showed that although the minor allele shifts channel activation by −4.3 mV, a proexcitatory attribute, it accelerates inactivation, an antiexcitatory attribute, with the net effect being reduced repetitive firing of dorsal root ganglion neurons, consistent with lower mechanical pain sensitivity. Conclusions: At the association and mechanistic levels, the SCN10A single nucleotide polymorphism rs6795970 biases human pain sensitivity. PMID:27590072

Modelling the dorsal root ganglia using human pluripotent stem cells: A platform to study peripheral neuropathies.

PubMed

Viventi, Serena; Dottori, Mirella

2018-07-01

Sensory neurons of the dorsal root ganglia (DRG) are the primary responders to stimuli inducing feelings of touch, pain, temperature, vibration, pressure and muscle tension. They consist of multiple subpopulations based on their morphology, molecular and functional properties. Our understanding of DRG sensory neurons has been predominantly driven by rodent studies and using transformed cell lines, whereas less is known about human sensory DRG neurons simply because of limited availability of human tissue. Although these previous studies have been fundamental for our understanding of the sensory system, it is imperative to profile human DRG subpopulations as it is becoming evident that human sensory neurons do not share the identical molecular and functional properties found in other species. Furthermore, there are wide range of diseases and disorders that directly/indirectly cause sensory neuronal degeneration or dysfunctionality. Having an in vitro source of human DRG sensory neurons is paramount for studying their development, unique neuronal properties and for accelerating regenerative therapies to treat sensory neuropathies. Here we review the major studies describing generation of DRG sensory neurons from human pluripotent stem cells and fibroblasts and the gaps that need to be addressed for using in vitro-generated human DRG neurons to model human DRG tissue. Copyright © 2018 Elsevier Ltd. All rights reserved.

Glial cells isolated from dorsal root ganglia express prostaglandin E(2) (EP(4)) and prostacyclin (IP) receptors.

PubMed

Ng, Kai Yu; Wong, Yung Hou; Wise, Helen

2011-07-01

Isolated cells from adult rat dorsal root ganglia (DRG) are frequently used as a model system to study responses of primary sensory neurons to nociceptor sensitizing agents such as prostaglandin E(2) and prostacyclin, which are presumed to act only on the neurons in typical mixed cell cultures. In the present study, we evaluated the expression of prostaglandin E(2) (EP(4)) and prostacyclin (IP) receptors in cultures of mixed DRG cells and in purified DRG glia. We show here that EP(4) and IP receptor agonists stimulated adenylyl cyclase activity in both mixed DRG cells and in purified DRG glia, and that these responses were specifically inhibited by EP(4) and IP receptor antagonists, respectively. The presence of EP(4) and IP receptors in DRG glia was further confirmed by the expression of EP(4) and IP receptor immunoreactivity and mRNA. With the increasing awareness of neuron-glial interactions within intact DRG and the use of isolated DRG cells in the study of mechanisms underlying nociception, it will be essential to consider the role played by EP(4) and IP receptor-expressing glial cells when evaluating prostanoid-induced sensitization of DRG neurons. Copyright © 2011 Elsevier B.V. All rights reserved.

Chronic monitoring of lower urinary tract activity via a sacral dorsal root ganglia interface

NASA Astrophysics Data System (ADS)

Khurram, Abeer; Ross, Shani E.; Sperry, Zachariah J.; Ouyang, Aileen; Stephan, Christopher; Jiman, Ahmad A.; Bruns, Tim M.

2017-06-01

Objective. Our goal is to develop an interface that integrates chronic monitoring of lower urinary tract (LUT) activity with stimulation of peripheral pathways. Approach. Penetrating microelectrodes were implanted in sacral dorsal root ganglia (DRG) of adult male felines. Peripheral electrodes were placed on or in the pudendal nerve, bladder neck and near the external urethral sphincter. Supra-pubic bladder catheters were implanted for saline infusion and pressure monitoring. Electrode and catheter leads were enclosed in an external housing on the back. Neural signals from microelectrodes and bladder pressure of sedated or awake-behaving felines were recorded under various test conditions in weekly sessions. Electrodes were also stimulated to drive activity. Main results. LUT single- and multi-unit activity was recorded for 4-11 weeks in four felines. As many as 18 unique bladder pressure single-units were identified in each experiment. Some channels consistently recorded bladder afferent activity for up to 41 d, and we tracked individual single-units for up to 23 d continuously. Distension-evoked and stimulation-driven (DRG and pudendal) bladder emptying was observed, during which LUT sensory activity was recorded. Significance. This chronic implant animal model allows for behavioral studies of LUT neurophysiology and will allow for continued development of a closed-loop neuroprosthesis for bladder control.

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

PubMed

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

2016-03-01

Complex regional pain syndrome (CRPS) is thought to have an auto-immune component. One such target recently proposed from the effects of auto-immune IgGs on Ca(2+) transients in cardiac myocytes and cell lines is the α1-adrenoceptor. We have tested whether such IgGs exerted comparable effects on nociceptive sensory neurons isolated from rat dorsal root ganglia. Depolarisation-induced [Ca(2+)]i transients were generated by applying 30 mM KCl for 2 min and monitored by Fura-2 fluorescence imaging. No IgGs tested (including 3 from CRPS patients) had any significant effect on these [Ca(2+)]i transients. However, IgG from one CRPS patient consistently and significantly reduced the K(+)-induced response of cells that had been pre-incubated for 24h with a mixture of inflammatory mediators (1 μM histamine, 5-hydroxytryptamine, bradykinin and PGE2). Since this pre-incubation also appeared to induce a comparable inhibitory response to the α1-agonist phenylephrine, this is compatible with the α1-adrenoceptor as a target for CRPS auto-immunity. A mechanism whereby this might enhance pain is suggested. Copyright © 2015. Published by Elsevier Inc.

Molecular cloning and expression of rat and mouse B61 gene: implications on organogenesis.

PubMed

Takahashi, H; Ikeda, T

1995-09-07

ECK is a member of EPH receptor protein-tyrosine kinase subfamily and human B61 has been identified as the ligand for ECK recently. In order to better understand the roles of B61-ECK signalling pathway in mammalian development, we have cloned rat and mouse B61 cDNA and examined the expression pattern during rat development. Sequence analysis has revealed that there is a considerable degree of identity among rat, mouse and human B61 (98.0% between rat and mouse, 86.3% between rat and human in amino acid level). Examination of B61 mRNA expression by in situ hybridization analysis revealed tight association of B61 with endothelial cells at an early stage and epithelial cells in various tissues including lung, kidney, intestine, skin at later stage of organogenesis. In the developing skeletal system, B61 is expressed in periosteum, perichondrium and hypertrophic chondrocytes and osteoblasts. In the developing nervous system, expression of B61 is restricted in the neurons of dorsal root ganglia. These expression profiles of B61 in epithelial cells of various organs, developing skeletal system and dorsal root ganglia match those of ECK. Our data suggest that B61 plays pivotal roles in organogenesis, especially vasculogenesis/angiogenesis and epithelial cell proliferation/differentiation.

An oral form of methylglyoxal-bis-guanylhydrazone reduces monocyte activation and traffic to the dorsal root ganglia in a primate model of HIV-peripheral neuropathy.

PubMed

Lakritz, Jessica R; Yalamanchili, Samshita; Polydefkis, Michael J; Miller, Andrew D; McGrath, Michael S; Williams, Kenneth C; Burdo, Tricia H

2017-08-01

Peripheral neuropathy (PN) is a major comorbidity of HIV infection that is caused in part by chronic immune activation. HIV-PN is associated with infiltration of monocytes/macrophages to the dorsal root ganglia (DRG) causing neuronal loss and formation of Nageotte nodules. Here, we used an oral form of methylglyoxal-bis-guanylhydrazone (MGBG), a polyamine biosynthesis inhibitor, to specifically reduce activation of myeloid cells. MGBG is selectively taken up by monocyte/macrophages in vitro and inhibits HIV p24 expression and DNA viral integration in macrophages. Here, MGBG was administered to nine SIV-infected, CD8-depleted rhesus macaques at 21 days post-infection (dpi). An additional nine SIV-infected, CD8-depleted rhesus macaques were used as untreated controls. Cell traffic to tissues was measured by in vivo BrdU pulse labeling. MGBG treatment significantly diminished DRG histopathology and reduced the number of CD68+ and CD163+ macrophages in DRG tissue. The number of recently trafficked BrdU+ cells in the DRG was significantly reduced with MGBG treatment. Despite diminished DRG pathology, intraepidermal nerve fiber density (IENFD) did not recover after treatment with MGBG. These data suggest that MGBG alleviated DRG pathology and inflammation.

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.

FGF and BMP derived from dorsal root ganglia regulate blastema induction in limb regeneration in Ambystoma mexicanum.

PubMed

Satoh, Akira; Makanae, Aki; Nishimoto, Yurie; Mitogawa, Kazumasa

2016-09-01

Urodele amphibians have a remarkable organ regeneration ability that is regulated by neural inputs. The identification of these neural inputs has been a challenge. Recently, Fibroblast growth factor (Fgf) and Bone morphogenic protein (Bmp) were shown to substitute for nerve functions in limb and tail regeneration in urodele amphibians. However, direct evidence of Fgf and Bmp being secreted from nerve endings and regulating regeneration has not yet been shown. Thus, it remained uncertain whether they were the nerve factors responsible for successful limb regeneration. To gather experimental evidence, the technical difficulties involved in the usage of axolotls had to be overcome. We achieved this by modifying the electroporation method. When Fgf8-AcGFP or Bmp7-AcGFP was electroporated into the axolotl dorsal root ganglia (DRG), GFP signals were detectable in the regenerating limb region. This suggested that Fgf8 and Bmp7 synthesized in neural cells in the DRG were delivered to the limbs through the long axons. Further knockdown experiments with double-stranded RNA interference resulted in impaired limb regeneration ability. These results strongly suggest that Fgf and Bmp are the major neural inputs that control the organ regeneration ability. Copyright © 2016 Elsevier Inc. All rights reserved.

Noise Enhances Action Potential Generation in Mouse Sensory Neurons via Stochastic Resonance.

PubMed

Onorato, Irene; D'Alessandro, Giuseppina; Di Castro, Maria Amalia; Renzi, Massimiliano; Dobrowolny, Gabriella; Musarò, Antonio; Salvetti, Marco; Limatola, Cristina; Crisanti, Andrea; Grassi, Francesca

2016-01-01

Noise can enhance perception of tactile and proprioceptive stimuli by stochastic resonance processes. However, the mechanisms underlying this general phenomenon remain to be characterized. Here we studied how externally applied noise influences action potential firing in mouse primary sensory neurons of dorsal root ganglia, modelling a basic process in sensory perception. Since noisy mechanical stimuli may cause stochastic fluctuations in receptor potential, we examined the effects of sub-threshold depolarizing current steps with superimposed random fluctuations. We performed whole cell patch clamp recordings in cultured neurons of mouse dorsal root ganglia. Noise was added either before and during the step, or during the depolarizing step only, to focus onto the specific effects of external noise on action potential generation. In both cases, step + noise stimuli triggered significantly more action potentials than steps alone. The normalized power norm had a clear peak at intermediate noise levels, demonstrating that the phenomenon is driven by stochastic resonance. Spikes evoked in step + noise trials occur earlier and show faster rise time as compared to the occasional ones elicited by steps alone. These data suggest that external noise enhances, via stochastic resonance, the recruitment of transient voltage-gated Na channels, responsible for action potential firing in response to rapid step-wise depolarizing currents.

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.

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.

PHARMACOLOGIC TREATMENT OF HYPERALGESIA EXPERIMENTALLY INDUCED BY NUCLEUS PULPOSUS

PubMed Central

de Souza Grava, André Luiz; Ferrari, Luiz Fernando; Parada, Carlos Amílcar; Defino, Helton Luiz Aparecido

2015-01-01

Objective: To evaluate the effect of anti-inflammatory drugs (dexamethasone, indomethacin, atenolol and indomethacin plus atenolol) and analgesic drugs (morphine) on hyperalgesia experimentally induced by the nucleus pulposus (NP) in contact with the L5 dorsal root ganglion (DRG). Methods: Thirty male Wistar rats of weights ranging from 220 to 250 g were used in the study. Hyperalgesia was induced by means of a fragment of NP removed from the sacrococcygeal region that was placed in contact with the L5 dorsal root ganglion. The 30 animals were divided into experimental groups according to the drug used. The drugs were administered for two weeks after the surgical procedure to induce hyperalgesia. Mechanical and thermal hyperalgesia was evaluated using the paw pressure test, von Frey electronic test and Hargreaves test, over a seven-week period. Results: The greatest reduction of hyperalgesia was observed in the group of animals treated with morphine, followed by dexamethasone, indomethacin and atenolol. Reductions in hyperalgesia were observed after drug administration ceased, except for the group of animals treated with morphine, in which there was an increase in hyperalgesia after discontinuation of the treatment. Conclusion: Hyperalgesia induced by NP contact with the DRG can be reduced through administration of anti-inflammatory and analgesic drugs, but a greater reduction was observed with the administration of dexamethasone. PMID:27026966

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.

Real-time control of hind limb functional electrical stimulation using feedback from dorsal root ganglia recordings

NASA Astrophysics Data System (ADS)

Bruns, Tim M.; Wagenaar, Joost B.; Bauman, Matthew J.; Gaunt, Robert A.; Weber, Douglas J.

2013-04-01

Objective. Functional electrical stimulation (FES) approaches often utilize an open-loop controller to drive state transitions. The addition of sensory feedback may allow for closed-loop control that can respond effectively to perturbations and muscle fatigue. Approach. We evaluated the use of natural sensory nerve signals obtained with penetrating microelectrode arrays in lumbar dorsal root ganglia (DRG) as real-time feedback for closed-loop control of FES-generated hind limb stepping in anesthetized cats. Main results. Leg position feedback was obtained in near real-time at 50 ms intervals by decoding the firing rates of more than 120 DRG neurons recorded simultaneously. Over 5 m of effective linear distance was traversed during closed-loop stepping trials in each of two cats. The controller compensated effectively for perturbations in the stepping path when DRG sensory feedback was provided. The presence of stimulation artifacts and the quality of DRG unit sorting did not significantly affect the accuracy of leg position feedback obtained from the linear decoding model as long as at least 20 DRG units were included in the model. Significance. This work demonstrates the feasibility and utility of closed-loop FES control based on natural neural sensors. Further work is needed to improve the controller and electrode technologies and to evaluate long-term viability.

Real-time control of hind limb functional electrical stimulation using feedback from dorsal root ganglia recordings

PubMed Central

Bruns, Tim M; Wagenaar, Joost B; Bauman, Matthew J; Gaunt, Robert A; Weber, Douglas J

2013-01-01

Objective Functional electrical stimulation (FES) approaches often utilize an open-loop controller to drive state transitions. The addition of sensory feedback may allow for closed-loop control that can respond effectively to perturbations and muscle fatigue. Approach We evaluated the use of natural sensory nerve signals obtained with penetrating microelectrode arrays in lumbar dorsal root ganglia (DRG) as real-time feedback for closed-loop control of FES-generated hind limb stepping in anesthetized cats. Main results Leg position feedback was obtained in near real-time at 50 ms intervals by decoding the firing rates of more than 120 DRG neurons recorded simultaneously. Over 5 m of effective linear distance was traversed during closed-loop stepping trials in each of two cats. The controller compensated effectively for perturbations in the stepping path when DRG sensory feedback was provided. The presence of stimulation artifacts and the quality of DRG unit sorting did not significantly affect the accuracy of leg position feedback obtained from the linear decoding model as long as at least 20 DRG units were included in the model. Significance This work demonstrates the feasibility and utility of closed-loop FES control based on natural neural sensors. Further work is needed to improve the controller and electrode technologies and to evaluate long-term viability. PMID:23503062

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

Noise Enhances Action Potential Generation in Mouse Sensory Neurons via Stochastic Resonance

PubMed Central

Onorato, Irene; D'Alessandro, Giuseppina; Di Castro, Maria Amalia; Renzi, Massimiliano; Dobrowolny, Gabriella; Musarò, Antonio; Salvetti, Marco; Limatola, Cristina; Crisanti, Andrea; Grassi, Francesca

2016-01-01

Noise can enhance perception of tactile and proprioceptive stimuli by stochastic resonance processes. However, the mechanisms underlying this general phenomenon remain to be characterized. Here we studied how externally applied noise influences action potential firing in mouse primary sensory neurons of dorsal root ganglia, modelling a basic process in sensory perception. Since noisy mechanical stimuli may cause stochastic fluctuations in receptor potential, we examined the effects of sub-threshold depolarizing current steps with superimposed random fluctuations. We performed whole cell patch clamp recordings in cultured neurons of mouse dorsal root ganglia. Noise was added either before and during the step, or during the depolarizing step only, to focus onto the specific effects of external noise on action potential generation. In both cases, step + noise stimuli triggered significantly more action potentials than steps alone. The normalized power norm had a clear peak at intermediate noise levels, demonstrating that the phenomenon is driven by stochastic resonance. Spikes evoked in step + noise trials occur earlier and show faster rise time as compared to the occasional ones elicited by steps alone. These data suggest that external noise enhances, via stochastic resonance, the recruitment of transient voltage-gated Na channels, responsible for action potential firing in response to rapid step-wise depolarizing currents. PMID:27525414

The Upregulation of α2δ-1 Subunit Modulates Activity-Dependent Ca2+ Signals in Sensory Neurons

PubMed Central

Margas, Wojciech; Cassidy, John S.

2015-01-01

As auxiliary subunits of voltage-gated Ca2+ channels, the α2δ proteins modulate membrane trafficking of the channels and their localization to specific presynaptic sites. Following nerve injury, upregulation of the α2δ-1 subunit in sensory dorsal root ganglion neurons contributes to the generation of chronic pain states; however, very little is known about the underlying molecular mechanisms. Here we show that the increased expression of α2δ-1 in rat sensory neurons leads to prolonged Ca2+ responses evoked by membrane depolarization. This mechanism is coupled to CaV2.2 channel-mediated responses, as it is blocked by a ω-conotoxin GVIA application. Once initiated, the prolonged Ca2+ transients are not dependent on extracellular Ca2+ and do not require Ca2+ release from the endoplasmic reticulum. The selective inhibition of mitochondrial Ca2+ uptake demonstrates that α2δ-1-mediated prolonged Ca2+ signals are buffered by mitochondria, preferentially activated by Ca2+ influx through CaV2.2 channels. Thus, by controlling channel abundance at the plasma membrane, the α2δ-1 subunit has a major impact on the organization of depolarization-induced intracellular Ca2+ signaling in dorsal root ganglion neurons. PMID:25878262

Progranulin contributes to endogenous mechanisms of pain defense after nerve injury in mice.

PubMed

Lim, Hee-Young; Albuquerque, Boris; Häussler, Annett; Myrczek, Thekla; Ding, Aihao; Tegeder, Irmgard

2012-04-01

Progranulin haploinsufficiency is associated with frontotemporal dementia in humans. Deficiency of progranulin led to exaggerated inflammation and premature aging in mice. The role of progranulin in adaptations to nerve injury and neuropathic pain are still unknown. Here we found that progranulin is up-regulated after injury of the sciatic nerve in the mouse ipsilateral dorsal root ganglia and spinal cord, most prominently in the microglia surrounding injured motor neurons. Progranulin knockdown by continuous intrathecal spinal delivery of small interfering RNA after sciatic nerve injury intensified neuropathic pain-like behaviour and delayed the recovery of motor functions. Compared to wild-type mice, progranulin-deficient mice developed more intense nociceptive hypersensitivity after nerve injury. The differences escalated with aging. Knockdown of progranulin reduced the survival of dissociated primary neurons and neurite outgrowth, whereas addition of recombinant progranulin rescued primary dorsal root ganglia neurons from cell death induced by nerve growth factor withdrawal. Thus, up-regulation of progranulin after neuronal injury may reduce neuropathic pain and help motor function recovery, at least in part, by promoting survival of injured neurons and supporting regrowth. A deficiency in this mechanism may increase the risk for injury-associated chronic pain. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Surgical correction of buried penis after traffic accident - a case report.

PubMed

Masuda, Hiroshi; Azuma, Haruhito; Segawa, Naoki; Iwamoto, Yusaku; Inamoto, Teruo; Takasaki, Noboru; Katsuoka, Yoji

2004-06-08

Buried penis, most commonly seen in children, is particularly debilitating in adults, resulting in inability to void while standing and it also affects vaginal penetration. We report a case of buried penis due to a traffic accident, which caused dislocation of the fractured pubic bone that shifted inside and pulled the penis by its suspensory ligament. A 55-year-old man was admitted to our hospital with a chief complaint of hidden penis while in the sitting position. He had suffered a pelvic fracture in a traffic accident four years previously, and his penis was covered with suprapubic fat when he was in a sitting position. He was unable to have sexual intercourse. We performed a penile lengthening procedure, including inverse V-Y-plasty of the dorsal skin of the penile root, suspensory desmotomy and fat removal, under general anesthesia. There was a good cosmetic result with satisfactory penile erection, which allowed successful sexual intercourse after surgery. We performed penile elongation surgery with inverse V-Y-plasty of the dorsal skin of the penile root, suspensory desmotomy, and fat removal. Surgical treatment of buried penis achieves marked aesthetic and functional improvement, and benefits the majority of patients, resulting in satisfactory erection and successful sexual intercourse.

Surgical correction of buried penis after traffic accident – a case report

PubMed Central

Masuda, Hiroshi; Azuma, Haruhito; Segawa, Naoki; Iwamoto, Yusaku; Inamoto, Teruo; Takasaki, Noboru; Katsuoka, Yoji

2004-01-01

Background Buried penis, most commonly seen in children, is particularly debilitating in adults, resulting in inability to void while standing and it also affects vaginal penetration. We report a case of buried penis due to a traffic accident, which caused dislocation of the fractured pubic bone that shifted inside and pulled the penis by its suspensory ligament. Case presentation A 55-year-old man was admitted to our hospital with a chief complaint of hidden penis while in the sitting position. He had suffered a pelvic fracture in a traffic accident four years previously, and his penis was covered with suprapubic fat when he was in a sitting position. He was unable to have sexual intercourse. We performed a penile lengthening procedure, including inverse V-Y-plasty of the dorsal skin of the penile root, suspensory desmotomy and fat removal, under general anesthesia. There was a good cosmetic result with satisfactory penile erection, which allowed successful sexual intercourse after surgery. Conculsion We performed penile elongation surgery with inverse V-Y-plasty of the dorsal skin of the penile root, suspensory desmotomy, and fat removal. Surgical treatment of buried penis achieves marked aesthetic and functional improvement, and benefits the majority of patients, resulting in satisfactory erection and successful sexual intercourse. PMID:15182380

RNA-Seq Analysis of Human Trigeminal and Dorsal Root Ganglia with a Focus on Chemoreceptors

PubMed Central

Flegel, Caroline; Schöbel, Nicole; Altmüller, Janine; Becker, Christian; Tannapfel, Andrea; Hatt, Hanns; Gisselmann, Günter

2015-01-01

The chemosensory capacity of the somatosensory system relies on the appropriate expression of chemoreceptors, which detect chemical stimuli and transduce sensory information into cellular signals. Knowledge of the complete repertoire of the chemoreceptors expressed in human sensory ganglia is lacking. This study employed the next-generation sequencing technique (RNA-Seq) to conduct the first expression analysis of human trigeminal ganglia (TG) and dorsal root ganglia (DRG). We analyzed the data with a focus on G-protein coupled receptors (GPCRs) and ion channels, which are (potentially) involved in chemosensation by somatosensory neurons in the human TG and DRG. For years, transient receptor potential (TRP) channels have been considered the main group of receptors for chemosensation in the trigeminal system. Interestingly, we could show that sensory ganglia also express a panel of different olfactory receptors (ORs) with putative chemosensory function. To characterize OR expression in more detail, we performed microarray, semi-quantitative RT-PCR experiments, and immunohistochemical staining. Additionally, we analyzed the expression data to identify further known or putative classes of chemoreceptors in the human TG and DRG. Our results give an overview of the major classes of chemoreceptors expressed in the human TG and DRG and provide the basis for a broader understanding of the reception of chemical cues. PMID:26070209

Changes in VGLUT1 and VGLUT2 expression in rat dorsal root ganglia and spinal cord following spared nerve injury.

PubMed

Wang, Hong-Sheng; Yu, Gang; Wang, Zhi-Tong; Yi, Shou-Pu; Su, Rui-Bin; Gong, Ze-Hui

2016-10-01

Disturbance of glutamate homeostasis is a well-characterized mechanism of neuropathic pain. Vesicular glutamate transporters (VGLUTs) determine glutamate accumulation in synaptic vesicles and their roles in neuropathic pain have been suggested by gene-knockout studies. Here, we investigated the spatio-temporal changes in VGLUT expression during the development of neuropathic pain in wild-type rats. Spared nerve injury (SNI) induced mechanical allodynia from postoperative day 1 to at least day 14. Expression of VGLUT1 and VGLUT2 in dorsal root ganglia and spinal cord was examined by western blot analyses on different postoperative days. We observed that VGLUT2 were selectively upregulated in crude vesicle fractions from the ipsilateral lumbar enlargement on postoperative days 7 and 14, while VGLUT1 was transiently downregulated in ipsilateral DRG (day 4) and contralateral lumbar enlargement (day 1). Upregulation of VGLUT2 was not accompanied by alterations in vesicular expression of synaptotagmin or glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Thus, VGLUTs expression, especially VGLUT2, is regulated following peripheral nerve injury. Temporal regulation of VGLUT2 expression in spinal cord may represent a novel presynaptic mechanism contributing to injury-induced glutamate imbalance and associated neuropathic pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

Opioid-induced hyperalgesia in chronic pain patients and the mitigating effects of gabapentin.

PubMed

Stoicea, Nicoleta; Russell, Daric; Weidner, Greg; Durda, Michael; Joseph, Nicholas C; Yu, Jeffrey; Bergese, Sergio D

2015-01-01

Chronic pain patients receiving opioid drugs are at risk for opioid-induced hyperalgesia (OIH), wherein opioid pain medication leads to a paradoxical pain state. OIH involves central sensitization of primary and secondary afferent neurons in the dorsal horn and dorsal root ganglion, similar to neuropathic pain. Gabapentin, a gamma-aminobutyric acid (GABA) analog anticonvulsant used to treat neuropathic pain, has been shown in animal models to reduce fentanyl hyperalgesia without compromising analgesic effect. Chronic pain patients have also exhibited lower opioid consumption and improved pain response when given gabapentin. However, few human studies investigating gabapentin use in OIH have been performed in recent years. In this review, we discuss the potential mechanisms that underlie OIH and provide a critical overview of interventional therapeutic strategies, especially the clinically-successful drug gabapentin, which may reduce OIH.

Topical treatments of Saussurea costus root and Thuja orientalis L. synergistically alleviate atopic dermatitis-like skin lesions by inhibiting protease-activated receptor-2 and NF-κB signaling in HaCaT cells and Nc/Nga mice.

PubMed

Yang, Hye Jeong; Kim, Min Jung; Kang, Suna; Moon, Na Rang; Kim, Da Sol; Lee, Na Ra; Kim, Kang Sung; Park, Sunmin

2017-03-06

The root of Saussurea costus (Aucklandia lappa Decne, Aucklandiae Radix, SC) and Thuja orientalis L. (TOL) have been traditionally used as anti-inflammatory agents in Korea. However, they have not been studied for the efficacy of atopic dermatitis (AD) treatment, a chronic inflammatory skin disease. We investigated the efficacy of topical applications with 1,3-butyleneglycol extracts of SC and TOL to alleviate the symptoms of AD. HaCaT cells and the dorsal skin of Nc/Nga mice had a local exposure of house mite extracts and 2,4-dinitrochlorobenzene (DNCB), respectively. After lesions developed, we topically applied 1,3-butylen glycol (vehicle; control), SC (30%), TOL (30%), or SC (15%)+TOL (15%) to the skin lesions for 5 weeks. The normal-control was not exposed to DNCB. The skin thickness, mast cell infiltration, serum immunoglobulin E (IgE) and IgG1 and gene expressions of interleukin (IL)-4, IL-13, and IFN-γ in the dorsal skin and HaCaT cells were measured. Chlorogenic acid (129.6±10.2μg/g) for SC and catechin and apigenin (93.4±13.2 and 16.9±1.3μg/g, respectively) for TOL were used as indicator compounds for the strength of the extracts. SC+TOL decreased the expression of protease-activated receptor-2 and ICAM-1 and the release of TNF-α and IL-6 in HaCaT cells activated by 3μg/mL house mite extracts in comparison to either of SC or TOL alone. In Nc/Nga mice challenged with DNCB, SC+TOL synergistically attenuated clinical symptoms of AD such as erythema, hemorrhage, edema, excoriation and dryness in the dorsal skin better than either SC or TOL alone. Histological analysis of the dorsal skin also showed that SC+TOL treatment significantly and additively decreased the inflammatory cellular infiltrate, including mast cells and eosinophils in comparison to either of SC or TOL. SC+TOL also decreased serum IgE and IgG1 levels and the expression of IFN-γ, IL-4, and IL-13 mRNA in dorsal skin in DNCB-treated Nc/Nga mice. SC+TOL relieved the symptoms of AD by reducing pro-inflammatory activity and over-activated immune responses. These data suggest that SC+TOL may be an effective alternative intervention for the management of AD. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

TRPV4 inhibition prevents paclitaxel-induced neurotoxicity in preclinical models.

PubMed

Boehmerle, Wolfgang; Huehnchen, Petra; Lee, Sabrina Lin Lin; Harms, Christoph; Endres, Matthias

2018-04-30

Paclitaxel is a cytotoxic drug which frequently causes sensory peripheral neuropathy in patients. Increasing evidence suggests that altered intracellular calcium (Ca 2+ ) signals play an important role in the pathogenesis of this condition. In the present study, we examined the interplay between Ca 2+ release channels in the endoplasmic reticulum (ER) and Ca 2+ permeable channels in the plasma membrane in the context of paclitaxel mediated neurotoxicity. We observed that in small to medium size dorsal root ganglia neurons (DRGN) the inositol-trisphosphate receptor (InsP 3 R) type 1 was often concentrated in the periphery of cells, which is in contrast to homogenous ER distribution. G protein-coupled designer receptors were used to further elucidate phosphoinositide mediated Ca 2+ signaling: This approach showed strong InsP 3 mediated Ca 2+ signals close to the plasma membrane, which can be amplified by Ca 2+ entry through TRPV4 channels. In addition, our results support a physical interaction and partial colocalization of InsP 3 R1 and TRPV4 channels. In the context of paclitaxel-induced neurotoxicity, blocking Ca 2+ influx through TRPV4 channels reduced cell death in cultured DRGN. Pretreatment of mice with the pharmacological TRPV4 inhibitor HC067047 prior to paclitaxel injections prevented electrophysiological and behavioral changes associated with paclitaxel-induced neuropathy. In summary, these results underline the relevance of TRPV4 signaling for the pathogenesis of paclitaxel-induced neuropathy and suggest novel preventive strategies. Copyright © 2018 Elsevier Inc. All rights reserved.

Deep cytoplasmic rearrangements in ventralized Xenopus embryos

NASA Technical Reports Server (NTRS)

Brown, E. E.; Denegre, J. M.; Danilchik, M. V.

1993-01-01

Following fertilization in Xenopus, dramatic rearrangements of the egg cytoplasm relocalize maternally synthesized egg components. During the first cell cycle the vegetal yolk mass rotates relative to the egg surface, toward the sperm entry point (SEP) (J. P. Vincent, G. F. Oster, and J. C. Gerhart, 1986, Dev. Biol. 113, 484-500), while concomitant deep cytoplasmic rearrangements occur in the animal hemisphere (M. V. Danilchik and J. M. Denegre, 1991, Development 111, 845-856). In this paper we examine the role of vegetal yolk mass rotation in producing the animal cytoplasmic rearrangements. We inhibited rotation by uv-irradiating embryos during the first cell cycle, a treatment that yields an extremely ventralized phenotype. Both uv-irradiated embryos and unirradiated control embryos show cytoplasmic rearrangements in the animal hemisphere during the first cell cycle. Cytoplasmic rearrangements on the SEP side of the embryo associated with the path of the sperm pronucleus, plus a swirl on the anti-SEP (dorsal) side, are seen, whether or not yolk mass rotation has occurred. This result suggests a role for the expanding sperm aster in directing animal hemisphere cytoplasmic movements. In unirradiated control embryos the anti-SEP (dorsal) swirl is larger than that in uv-irradiated embryos and often extends into the vegetal hemisphere, consistent with the animal cytoplasm having been pulled dorsally and vegetally by the sliding vegetal yolk mass. Thus the yolk mass rotation may normally enhance the dorsalward cytoplasmic movement, begun by the sperm aster, enough to induce normal axis formation. We extended our observations of unirradiated control and uv-irradiated embryos through early cleavages. The vegetal extent of the anti-SEP (dorsal) swirl pattern seen in control embryos persists through the early cleavage period, such that labeled animal cytoplasm extends deep into dorsal third-tier blastomeres at the 32-cell stage. Significantly, in uv-irradiated embryos, which have not undergone vegetal rotation, most of this labeled material remains more equatorial.

Evaluation of Five Tests for Sensitivity to Functional Deficits following Cervical or Thoracic Dorsal Column Transection in the Rat

PubMed Central

Eggers, Ruben; Tuinenbreijer, Lizz; Kouwenhoven, Dorette; Verhaagen, Joost; Mason, Matthew R. J.

2016-01-01

The dorsal column lesion model of spinal cord injury targets sensory fibres which originate from the dorsal root ganglia and ascend in the dorsal funiculus. It has the advantages that fibres can be specifically traced from the sciatic nerve, verifiably complete lesions can be performed of the labelled fibres, and it can be used to study sprouting in the central nervous system from the conditioning lesion effect. However, functional deficits from this type of lesion are mild, making assessment of experimental treatment-induced functional recovery difficult. Here, five functional tests were compared for their sensitivity to functional deficits, and hence their suitability to reliably measure recovery of function after dorsal column injury. We assessed the tape removal test, the rope crossing test, CatWalk gait analysis, and the horizontal ladder, and introduce a new test, the inclined rolling ladder. Animals with dorsal column injuries at C4 or T7 level were compared to sham-operated animals for a duration of eight weeks. As well as comparing groups at individual timepoints we also compared the longitudinal data over the whole time course with linear mixed models (LMMs), and for tests where steps are scored as success/error, using generalized LMMs for binomial data. Although, generally, function recovered to sham levels within 2–6 weeks, in most tests we were able to detect significant deficits with whole time-course comparisons. On the horizontal ladder deficits were detected until 5–6 weeks. With the new inclined rolling ladder functional deficits were somewhat more consistent over the testing period and appeared to last for 6–7 weeks. Of the CatWalk parameters base of support was sensitive to cervical and thoracic lesions while hind-paw print-width was affected by cervical lesion only. The inclined rolling ladder test in combination with the horizontal ladder and the CatWalk may prove useful to monitor functional recovery after experimental treatment in this lesion model. PMID:26934672

c-Maf is required for the development of dorsal horn laminae III/IV neurons and mechanoreceptive DRG axon projections.

PubMed

Hu, Jia; Huang, Tianwen; Li, Tingting; Guo, Zhen; Cheng, Leping

2012-04-18

Establishment of proper connectivity between peripheral sensory neurons and their central targets is required for an animal to sense and respond to various external stimuli. Dorsal root ganglion (DRG) neurons convey sensory signals of different modalities via their axon projections to distinct laminae in the dorsal horn of the spinal cord. In this study, we found that c-Maf was expressed predominantly in the interneurons of laminae III/IV, which primarily receive inputs from mechanoreceptive DRG neurons. In the DRG, c-Maf⁺ neurons also coexpressed neurofilament-200, a marker for the medium- and large-diameter myelinated afferents that transmit non-noxious information. Furthermore, mouse embryos deficient in c-Maf displayed abnormal development of dorsal horn laminae III/IV neurons, as revealed by the marked reduction in the expression of several marker genes for these neurons, including those for transcription factors MafA and Rora, GABA(A) receptor subunit α5, and neuropeptide cholecystokinin. In addition, among the four major subpopulations of DRG neurons marked by expression of TrkA, TrkB, TrkC, and MafA/GFRα2/Ret, c-Maf was required selectively for the proper differentiation of MafA⁺/Ret⁺/GFRα2⁺ low-threshold mechanoreceptors (LTMs). Last, we found that the central and peripheral projections of mechanoreceptive DRG neurons were compromised in c-Maf deletion mice. Together, our results indicate that c-Maf is required for the proper development of MafA⁺/Ret⁺/GFRα2⁺ LTMs in the DRG, their afferent projections in the dorsal horn and Pacinian corpuscles, as well as neurons in laminae III/IV of the spinal cord.

Influence of preservative and mounting media on the size and shape of monogenean sclerites.

PubMed

Fankoua, Severin-Oscar; Bitja Nyom, Arnold R; Bahanak, Dieu Ne Dort; Bilong Bilong, Charles F; Pariselle, Antoine

2017-08-01

Based on Cichlidogyrus sp. (Monogenea, Ancyrocephalidae) specimens from Hemichromis sp. hosts, we tested the influence of different methods to fix/preserve samples/specimens [frozen material, alcohol or formalin preserved, museum process for fish preservation (fixed in formalin and preserved in alcohol)] and different media used to mount the slides [tap water, glycerin ammonium picrate (GAP), Hoyer's one (HM)] on the size/shape of sclerotized parts of monogenean specimens. The results show that the use of HM significantly increases the size of haptoral sclerites [marginal hooks I, II, IV, V, and VI; dorsal bar length, width, distance between auricles and auricle length, ventral bar length and width], and changes their shape [angle opening between shaft and guard (outer and inner roots) in both ventral and dorsal anchors, ventral bar much wider, dorsal one less curved]. This influence seems to be reduced when specimens/samples are fixed in formalin. The systematics of Monogenea being based on the size and shape of their sclerotized parts, to prevent misidentifications or description of invalid new species, we recommend the use of GAP as mounting medium; Hoyer's one should be restricted to monogenean specimens fixed for a long time which are more shrunken.

The relationship of global form and motion detection to reading fluency.

PubMed

Englund, Julia A; Palomares, Melanie

2012-08-15

Visual motion processing in typical and atypical readers has suggested aspects of reading and motion processing share a common cortical network rooted in dorsal visual areas. Few studies have examined the relationship between reading performance and visual form processing, which is mediated by ventral cortical areas. We investigated whether reading fluency correlates with coherent motion detection thresholds in typically developing children using random dot kinematograms. As a comparison, we also evaluated the correlation between reading fluency and static form detection thresholds. Results show that both dorsal and ventral visual functions correlated with components of reading fluency, but that they have different developmental characteristics. Motion coherence thresholds correlated with reading rate and accuracy, which both improved with chronological age. Interestingly, when controlling for non-verbal abilities and age, reading accuracy significantly correlated with thresholds for coherent form detection but not coherent motion detection in typically developing children. Dorsal visual functions that mediate motion coherence seem to be related maturation of broad cognitive functions including non-verbal abilities and reading fluency. However, ventral visual functions that mediate form coherence seem to be specifically related to accurate reading in typically developing children. Copyright © 2012 Elsevier Ltd. All rights reserved.

Asymmetric lumbosacral transitional vertebra and subsequent disc protrusion in a cocker spaniel

PubMed Central

Archer, Rebecca; Sissener, Thomas; Connery, Neil; Spotswood, Tim

2010-01-01

A 10-year-old cocker spaniel bitch presented with severe lumbosacral pain and acute onset left pelvic limb lameness. A diagnosis of asymmetric lumbosacral transitional vertebra with disc protrusion at L6-L7 was made by computed tomography. The cauda equina and left L6 nerve root were surgically decompressed with a dorsal laminectomy and lateral foraminotomy, which led to rapid resolution of the clinical signs. PMID:20514255

Secretagogin is expressed in sensory CGRP neurons and in spinal cord of mouse and complements other calcium-binding proteins, with a note on rat and human

PubMed Central

2012-01-01

Background Secretagogin (Scgn), a member of the EF-hand calcium-binding protein (CaBP) superfamily, has recently been found in subsets of developing and adult neurons. Here, we have analyzed the expression of Scgn in dorsal root ganglia (DRGs) and trigeminal ganglia (TGs), and in spinal cord of mouse at the mRNA and protein levels, and in comparison to the well-known CaBPs, calbindin D-28k, parvalbumin and calretinin. Rat DRGs, TGs and spinal cord, as well as human DRGs and spinal cord were used to reveal phylogenetic variations. Results We found Scgn mRNA expressed in mouse and human DRGs and in mouse ventral spinal cord. Our immunohistochemical data showed a complementary distribution of Scgn and the three CaBPs in mouse DRG neurons and spinal cord. Scgn was expressed in ~7% of all mouse DRG neuron profiles, mainly small ones and almost exclusively co-localized with calcitonin gene-related peptide (CGRP). This co-localization was also seen in human, but not in rat DRGs. Scgn could be detected in the mouse sciatic nerve and accumulated proximal to its constriction. In mouse spinal cord, Scgn-positive neuronal cell bodies and fibers were found in gray matter, especially in the dorsal horn, with particularly high concentrations of fibers in the superficial laminae, as well as in cell bodies in inner lamina II and in some other laminae. A dense Scgn-positive fiber network and some small cell bodies were also found in the superficial dorsal horn of humans. In the ventral horn, a small number of neurons were Scgn-positive in mouse but not rat, confirming mRNA distribution. Both in mouse and rat, a subset of TG neurons contained Scgn. Dorsal rhizotomy strongly reduced Scgn fiber staining in the dorsal horn. Peripheral axotomy did not clearly affect Scgn expression in DRGs, dorsal horn or ventral horn neurons in mouse. Conclusions Scgn is a CaBP expressed in a subpopulation of nociceptive DRG neurons and their processes in the dorsal horn of mouse, human and rat, the former two co-expressing CGRP, as well as in dorsal horn neurons in all three species. Functional implications of these findings include the cellular refinement of sensory information, in particular during the processing of pain. PMID:23102406

Remodeling of the Infection Chamber before Infection Thread Formation Reveals a Two-Step Mechanism for Rhizobial Entry into the Host Legume Root Hair1

PubMed Central

Teillet, Alice; Chabaud, Mireille; Ivanov, Sergey; Genre, Andrea; Limpens, Erik; de Carvalho-Niebel, Fernanda; Barker, David G.

2015-01-01

In many legumes, root entry of symbiotic nitrogen-fixing rhizobia occurs via host-constructed tubular tip-growing structures known as infection threads (ITs). Here, we have used a confocal microscopy live-tissue imaging approach to investigate early stages of IT formation in Medicago truncatula root hairs (RHs) expressing fluorescent protein fusion reporters. This has revealed that ITs only initiate 10 to 20 h after the completion of RH curling, by which time major modifications have occurred within the so-called infection chamber, the site of bacterial entrapment. These include the accumulation of exocytosis (M. truncatula Vesicle-Associated Membrane Protein721e)- and cell wall (M. truncatula EARLY NODULIN11)-associated markers, concomitant with radial expansion of the chamber. Significantly, the infection-defective M. truncatula nodule inception-1 mutant is unable to create a functional infection chamber. This underlines the importance of the NIN-dependent phase of host cell wall remodeling that accompanies bacterial proliferation and precedes IT formation, and leads us to propose a two-step model for rhizobial infection initiation in legume RHs. PMID:25659382

Mechanisms underlying recurrent inhibition in the sacral parasympathetic outflow to the urinary bladder.

PubMed Central

de Groat, W C

1976-01-01

1. In cats with the sacral dorsal roots cut on one side electrical stimulation (15-40 c/s) of the central end of the transected ipsilateral pelvic nerve depressed spontaneous bladder contractions. The depression was abolished by transecting the ipsilateral sacral ventral roots. 2. Electrical stimulation of acutely or chronically transected ('deafferented') sacral ventral roots depressed spontaneous bladder contractions and the firing of sacral parasympathetic preganglionic neurones innervating the bladder. The depression of neuronal firing occurred ipsilateral and contralateral to the point of stimulation, but only occurred with stimulation of sacral roots containing preganglionic axons and only with stimulation of sacral roots containing preganglionic axons and only at intensities of stimulation (0-7-4V) above the threshold for activation of these axons. 3. The inhibitory responses were not abolished by strychnine administered by micro-electrophoresis to preganglionic neurones, but were blocked by the intravenous administration of strychnine. 4. The firing of preganglionic neurones elicited by micro-electrophoretic administration of an excitant amino acid (DL-homocysteic acid) was not depressed by stimulation of the ventral roots. 5. It is concluded that the inhibition of the sacral outflow to the bladder by stimulation of sacral ventral roots is related to antidromic activation of vesical preganglionic axons. Collaterals of these axons must excite inhibitory interneurones which in turn depress transmission at a site on the micturition reflex pathway prior to the preganglionic neurones. PMID:950603

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.

Accumulation of methylglyoxal increases the advanced glycation end-product levels in DRG and contributes to lumbar disk herniation-induced persistent pain.

PubMed

Liu, Cui-Cui; Zhang, Xin-Sheng; Ruan, Yu-Ting; Huang, Zhu-Xi; Zhang, Su-Bo; Liu, Meng; Luo, Hai-Jie; Wu, Shao-Ling; Ma, Chao

2017-08-01

Lumbar disk herniation (LDH) with discogenic low back pain and sciatica is a common and complicated musculoskeletal disorder. The underlying mechanisms are poorly understood, and there are no effective therapies for LDH-induced pain. In the present study, we found that the patients who suffered from LDH-induced pain had elevated plasma methylglyoxal (MG) levels. In rats, implantation of autologous nucleus pulposus (NP) to the left lumbar 5 spinal nerve root, which mimicked LDH, induced mechanical allodynia, increased MG level in plasma and dorsal root ganglion (DRG), and enhanced the excitability of small DRG neurons (<30 μm in diameter). Intrathecal injection of MG also induced mechanical allodynia, and its application to DRG neurons ex vivo increased the number of action potentials evoked by depolarizing current pulses. Furthermore, inhibition of MG accumulation by aminoguanidine attenuated the enhanced excitability of small DRG neurons and the mechanical allodynia induced by NP implantation. In addition, NP implantation increased levels of advanced glycation end products (AGEs) in DRG, and intrathecal injection of MG-derived AGEs induced the mechanical allodynia and DRG neuronal hyperactivity. Intrathecal injection of MG also significantly increased the expression of AGEs in DRG. Importantly, scavenging of MG by aminoguanidine also attenuated the increase in AGEs induced by NP implantation. These results suggested that LDH-induced MG accumulation contributed to persistent pain by increasing AGE levels. Thus generation of AGEs from MG may represent a target for treatment of LDH-induced pain. NEW & NOTEWORTHY Our study demonstrates that methylglyoxal accumulation via increasing advanced glycation end-product levels in dorsal root ganglion contributes to the persistent pain induced by lumbar disk herniation, which proposed potential targets for the treatment of lumbar disk herniation-induced persistent pain. Copyright © 2017 the American Physiological Society.

Long non-coding RNA CCAT1 modulates neuropathic pain progression through sponging miR-155.

PubMed

Dou, Lidong; Lin, Hongqi; Wang, Kaiwei; Zhu, Guosong; Zou, Xuli; Chang, Enqiang; Zhu, Yongfeng

2017-10-27

Neuropathic pain is caused by dysfunction or primary injury of the somatosensory nervous system. Long noncoding RNAs (lncRNAs) play important roles in the development of neuropathic pain. However, the effects of lncRNA colon cancer associated transcript-1 (CCAT1) in neuropathic pain have not been reported. The model of bilateral sciatic nerve chronic constriction injuries (bCCI) is regarded as long-lasting mechanical hypersensitivity and cold allodynia, which is the representative symptom in the human subjects suffering from the neuropathic pain. In this study, we found that CCAT1 expression was decreased in the spinal dorsal horn, dorsal root ganglion (DRG), hippocampus, and anterior cingulate cortex (ACC) of rats with bCCI. The rats of bCCI presented the cold allodynia after the 14 th day of postoperation. We furtherly showed that lncRNA CCAT1 decreased miR-155 expression and enhanced Serum and glucocorticoid regulated protein kinase 3 (SGK3) expression in the NGF-differentiated PC12 cell. We found that miR-155 expression was increased in the spinal dorsal horn, DRG, hippocampus, and ACC of rats with bCCI injuries. However, SGK3 expression was downregulated in the spinal dorsal horn, DRG, hippocampus, and ACC of rats with bCCI injuries. Moreover, lncRNA CCAT1 overexpression could alleviate the pain thresholds and inhibited expression of SGK3 could rescue this effect. In conclusion, these results suggested the crucial roles of CCAT1 and SGK3 in the neuropathic pain.

Long non-coding RNA CCAT1 modulates neuropathic pain progression through sponging miR-155

PubMed Central

Dou, Lidong; Lin, Hongqi; Wang, Kaiwei; Zhu, Guosong; Zou, Xuli; Chang, Enqiang; Zhu, Yongfeng

2017-01-01

Neuropathic pain is caused by dysfunction or primary injury of the somatosensory nervous system. Long noncoding RNAs (lncRNAs) play important roles in the development of neuropathic pain. However, the effects of lncRNA colon cancer associated transcript-1 (CCAT1) in neuropathic pain have not been reported. The model of bilateral sciatic nerve chronic constriction injuries (bCCI) is regarded as long-lasting mechanical hypersensitivity and cold allodynia, which is the representative symptom in the human subjects suffering from the neuropathic pain. In this study, we found that CCAT1 expression was decreased in the spinal dorsal horn, dorsal root ganglion (DRG), hippocampus, and anterior cingulate cortex (ACC) of rats with bCCI. The rats of bCCI presented the cold allodynia after the 14th day of postoperation. We furtherly showed that lncRNA CCAT1 decreased miR-155 expression and enhanced Serum and glucocorticoid regulated protein kinase 3 (SGK3) expression in the NGF-differentiated PC12 cell. We found that miR-155 expression was increased in the spinal dorsal horn, DRG, hippocampus, and ACC of rats with bCCI injuries. However, SGK3 expression was downregulated in the spinal dorsal horn, DRG, hippocampus, and ACC of rats with bCCI injuries. Moreover, lncRNA CCAT1 overexpression could alleviate the pain thresholds and inhibited expression of SGK3 could rescue this effect. In conclusion, these results suggested the crucial roles of CCAT1 and SGK3 in the neuropathic pain. PMID:29163801

Dense TRPV2 immunoreactivity defines a subset of motoneurons in the dorsal lateral nucleus of the spinal cord, the nucleus ambiguus and the trigeminal motor nucleus in rat

PubMed Central

LeWinter, Robin D.; Scherrer, Grégory; Basbaum, Allan I.

2008-01-01

The transient receptor potential cation channel TRPV2 is a member of the TRPV family of proteins and is a homologue of the capsaicin/vanilloid receptor (TRPV1). Like TRPV1, TRPV2 is expressed in a subset of dorsal root ganglia (DRG) neurons that project to superficial laminae of the spinal cord dorsal horn. Because noxious heat (>52°C) activates TRPV2 in transfected cells this channel has been implicated in the processing of high intensity thermal pain messages in vivo. In contrast to TRPV1, however, which is restricted to small diameter DRG neurons, there is significant TRPV2 immunoreactivity in a variety of CNS regions. The present report focuses on a subset of neurons in the brainstem and spinal cord of the rat including the dorsal lateral nucleus (DLN) of the spinal cord, the nucleus ambiguus, and the motor trigeminal nucleus. Double label immunocytochemistry with markers of motoneurons, combined with retrograde labeling, established that these cells are, in fact, motoneurons. With the exception of their smaller diameter, these cells did not differ from other motoneurons, which are only lightly TRPV2-immunoreactive. As for the majority of DLN neurons, the densely-labeled populations co-express androgen receptor and follow normal DLN ontogeny. The functional significance of the very intense TRPV2 expression in these three distinct spinal cord and brainstem motoneurons groups remains to be determined. PMID:18063314

An efficient cDNA-AFLP-based strategy for the identification of putative pathogenicity factors from the potato cyst nematode Globodera rostochiensis.

PubMed

Qin, L; Overmars, H; Helder, J; Popeijus, H; van der Voort, J R; Groenink, W; van Koert, P; Schots, A; Bakker, J; Smant, G

2000-08-01

A new strategy has been designed to identify putative pathogenicity factors from the dorsal or subventral esophageal glands of the potato cyst nematode Globodera rostochiensis. Three independent criteria were used for selection. First, genes of interest should predominantly be expressed in infective second-stage juveniles, and not, or to a far lesser extent, in younger developmental stages. For this, gene expression profiles from five different developmental stages were generated with cDNA-AFLP (amplified fragment length polymorphism). Secondly, the mRNA corresponding to such a putative pathogenicity factor should predominantly be present in the esophageal glands of pre-parasitic juveniles. This was checked by in situ hybridization. As a third criterion, these proteinaceous factors should be preceded by a signal peptide for secretion. Expression profiles of more than 4,000 genes were generated and three up-regulated, dorsal gland-specific proteins preceded by signal peptide for secretion were identified. No dorsal gland genes have been cloned before from plant-parasitic nematodes. The partial sequence of these three factors, A4, A18, and A41, showed no significant homology to any known gene. Their presence in the dorsal glands of infective juveniles suggests that these proteins could be involved in feeding cell initiation, and not in migration in the plant root or in protection against plant defense responses. Finally, the applicability of this new strategy in other plant-microbe interactions is discussed.

Cholinergic, serotoninergic and peptidergic components of the nervous system of Discocotyle sagittata (Monogenea:Polyopisthocotylea).

PubMed

Cable, J; Marks, N J; Halton, D W; Shaw, C; Johnston, C F; Tinsley, R C; Gannicott, A M

1996-12-01

Cholinergic, serotoninergic (5-HT) and peptidergic neuronal pathways have been demonstrated in both central and peripheral nervous systems of adult Discocotyle sagittata, using enzyme histochemistry and indirect immunocytochemistry in conjunction with confocal scanning laser microscopy. Antisera to 2 native flatworm neuropeptides, neuropeptide F and the FMRFamide-related peptide (FaRP), GNFFRFamide, were employed to detect peptide immunoreactivity. The CNS is composed of paired cerebral ganglia and connecting dorsal commissure, together with several paired longitudinal nerve cords. The main longitudinal nerve cords (lateral, ventral and dorsal) are interconnected at intervals by a series of annular cross-connectives, producing a ladder-like arrangement typical of the platyhelminth nervous system. At the level of the haptor, the ventral cords provide nerve roots which innervate each of the 9 clamps. Cholinergic and peptidergic neuronal organisation was similar, but distinct from that of the serotoninergic components. The PNS and reproductive system are predominantly innervated by peptidergic neurones.

Gaussian mixture clustering and imputation of microarray data.

PubMed

Ouyang, Ming; Welsh, William J; Georgopoulos, Panos

2004-04-12

In microarray experiments, missing entries arise from blemishes on the chips. In large-scale studies, virtually every chip contains some missing entries and more than 90% of the genes are affected. Many analysis methods require a full set of data. Either those genes with missing entries are excluded, or the missing entries are filled with estimates prior to the analyses. This study compares methods of missing value estimation. Two evaluation metrics of imputation accuracy are employed. First, the root mean squared error measures the difference between the true values and the imputed values. Second, the number of mis-clustered genes measures the difference between clustering with true values and that with imputed values; it examines the bias introduced by imputation to clustering. The Gaussian mixture clustering with model averaging imputation is superior to all other imputation methods, according to both evaluation metrics, on both time-series (correlated) and non-time series (uncorrelated) data sets.

FK1706, a novel non-immunosuppressive immunophilin ligand, modifies gene expression in the dorsal root ganglia during painful diabetic neuropathy.

PubMed

Yamazaki, Shunji; Yamaji, Takayuki; Murai, Nobuhito; Yamamoto, Hiroko; Matsuda, Takashi; Price, Raymond Daniel; Matsuoka, Nobuya

2012-06-01

FK1706, a non-immunosuppressive immunophilin ligand, potentiated nerve growth factor-induced neurite outgrowth, putatively mediated via FKBP-52 and the Ras/Raf/MAPK signaling pathway. It also improved mechanical allodynia accompanied by the recovery of intraepidermal nerve fiber density in a painful diabetic neuropathy in rats. The aim of this study was to demonstrate the gene expression profiling in dorsal root ganglion in streptozotocin-induced diabetic rats related to pain and anti-allodynia effects of FK1706 administration to elucidate the putative mechanisms of its neurotrophic activity in vivo. Here, we analyzed gene expression of the dorsal root ganglia using microarray together with behavioral measurement of mechanical allodynia in diabetic rats to try to capture the global fingerprint of changes in gene expression associated with FK1706 administration. The withdrawal threshold of streptozotocin-induced diabetic rats was measured by an electronic von Frey system. The gene expression of the ganglia from L4 to L6 obtained from streptozotocin-treated rats with or without chronic administration of FK1706 was analyzed using an Affymetrix GeneChip to extract interesting genes in the development of mechanical allodynia in diabetes and anti-allodynia effect of FK1706. Daily oral administration of FK1706 improved mechanical allodynia without decreasing plasma glucose levels. From gene expression analysis, the expression of thioredoxin interacting protein gene was sustained to increased change, whereas those of collagen I alpha1, II alpha1 and IX alpha1 genes were decreased from 2 to 4 weeks after streptozotocin injection. While no changes occurred after 1 week of commencing of FK1706 administration (2 weeks after streptozotocin injection), changes in expression more than 1.5-fold were observed for genes such as Ckm, Actn3, Atp2a1, Bglap, Acta1, Myl1, Tnnc2, and Mylpf at 2 weeks of FK1706 administration (3 weeks after streptozotocin injection). The genes RGD1564519, Hbb, LOC689064, Arpc4 and S100a9 were upregulated in comparison with streptozotocin-injected control group at 3 weeks of FK1706 administration; on the other hand, those of Actn3, Atp2a1 were downregulated by FK1706. FK1706 ameliorates mechanical allodynia with accompanying increases in gene expressions possibly related to neurite outgrowth, development, differentiation, and nociceptive sensitivity.

Practical considerations of linear accelerator-based frameless extracranial radiosurgery for treatment of occipital neuralgia for nonsurgical candidates.

PubMed

Denton, Travis R; Shields, Lisa B E; Howe, Jonathan N; Shanks, Todd S; Spalding, Aaron C

2017-07-01

Occipital neuralgia generally responds to medical or invasive procedures. Repeated invasive procedures generate increasing complications and are often contraindicated. Stereotactic radiosurgery (SRS) has not been reported as a treatment option largely due to the extracranial nature of the target as opposed to the similar, more established trigeminal neuralgia. A dedicated phantom study was conducted to determine the optimum imaging studies, fusion matrices, and treatment planning parameters to target the C2 dorsal root ganglion which forms the occipital nerve. The conditions created from the phantom were applied to a patient with medically and surgically refractory occipital neuralgia. A dose of 80 Gy in one fraction was prescribed to the C2 occipital dorsal root ganglion. The phantom study resulted in a treatment achieved with an average translational magnitude of correction of 1.35 mm with an acceptable tolerance of 0.5 mm and an average rotational magnitude of correction of 0.4° with an acceptable tolerance of 1.0°. For the patient, the spinal cord was 12.0 mm at its closest distance to the isocenter and received a maximum dose of 3.36 Gy, a dose to 0.35 cc of 1.84 Gy, and a dose to 1.2 cc of 0.79 Gy. The brain maximum dose was 2.20 Gy. Treatment time was 59 min for 18, 323 MUs. Imaging was performed prior to each arc delivery resulting in 21 imaging sessions. The average deviation magnitude requiring a positional or rotational correction was 0.96 ± 0.25 mm, 0.8 ± 0.41°, whereas the average deviation magnitude deemed within tolerance was 0.41 ± 0.12 mm, 0.57 ± 0.28°. Dedicated quality assurance of the treatment planning and delivery is necessary for safe and accurate SRS to the cervical spine dorsal root ganglion. With additional prospective study, linear accelerator-based frameless radiosurgery can provide an accurate, noninvasive alternative for treating occipital neuralgia where an invasive procedure is contraindicated. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Genome-wide association mapping and agronomic impact of cowpea root architecture.

PubMed

Burridge, James D; Schneider, Hannah M; Huynh, Bao-Lam; Roberts, Philip A; Bucksch, Alexander; Lynch, Jonathan P

2017-02-01

Genetic analysis of data produced by novel root phenotyping tools was used to establish relationships between cowpea root traits and performance indicators as well between root traits and Striga tolerance. Selection and breeding for better root phenotypes can improve acquisition of soil resources and hence crop production in marginal environments. We hypothesized that biologically relevant variation is measurable in cowpea root architecture. This study implemented manual phenotyping (shovelomics) and automated image phenotyping (DIRT) on a 189-entry diversity panel of cowpea to reveal biologically important variation and genome regions affecting root architecture phenes. Significant variation in root phenes was found and relatively high heritabilities were detected for root traits assessed manually (0.4 for nodulation and 0.8 for number of larger laterals) as well as repeatability traits phenotyped via DIRT (0.5 for a measure of root width and 0.3 for a measure of root tips). Genome-wide association study identified 11 significant quantitative trait loci (QTL) from manually scored root architecture traits and 21 QTL from root architecture traits phenotyped by DIRT image analysis. Subsequent comparisons of results from this root study with other field studies revealed QTL co-localizations between root traits and performance indicators including seed weight per plant, pod number, and Striga (Striga gesnerioides) tolerance. The data suggest selection for root phenotypes could be employed by breeding programs to improve production in multiple constraint environments.

Gamma Synuclein Promotes a Metastatic Phenotype in Breast and Ovarian Tumor Cells by Modulating the Rho Signal Transduction Activity

DTIC Science & Technology

2002-05-01

peripheral nervous system, such as dorsal root ganglia and trigeminal ganglia . Synoretin, the newest member of the synuclein family is expressed at high...involved in neuron development and function (43). The involvement of y-synuclein in human neoplastic diseases came to light when y-synuclein was...wed) are a famnily of small, highly conserved proteins exprssed predominanly in neurons . While a- synfucein is impicatad i neurodegenerative diseases

Carvacrol modulates voltage-gated sodium channels kinetics in dorsal root ganglia.

PubMed

Joca, Humberto Cavalcante; Vieira, Daiana Cardoso Oliveira; Vasconcelos, Aliny Perreira; Araújo, Demetrius Antônio Machado; Cruz, Jader Santos

2015-06-05

Recent studies have shown that many of plant-derived compounds interact with specific ion channels and thereby modulate many sensing mechanisms, such as nociception. The monoterpenoid carvacrol (5-isopropyl-2-methylphenol) has an anti-nociceptive effect related to a reduction in neuronal excitability and voltage-gated Na(+) channels (NaV) inhibition in peripheral neurons. However, the detailed mechanisms of carvacrol-induced inhibition of neuronal NaV remain elusive. This study explores the interaction between carvacrol and NaV in isolated dorsal root ganglia neurons. Carvacrol reduced the total voltage-gated Na(+) current and tetrodotoxin-resistant (TTX-R) Na(+) current component in a concentration-dependent manner. Carvacrol accelerates current inactivation and induced a negative-shift in voltage-dependence of steady-state fast inactivation in total and TTX-R Na(+) current. Furthermore, carvacrol slowed the recovery from inactivation. Carvacrol provoked a leftward shift in both the voltage-dependence of steady-state inactivation and activation of the TTX-R Na(+) current component. In addition, carvacrol-induced inhibition of TTX-R Na(+) current was enhanced by an increase in stimulation frequency and when neurons were pre-conditioned with long depolarization pulse (5s at -50 mV). Taken all results together, we herein demonstrated that carvacrol affects NaV gating properties. The present findings would help to explain the mechanisms underlying the analgesic activity of carvacrol. Copyright © 2015 Elsevier B.V. All rights reserved.

Downregulation of ClC-3 in dorsal root ganglia neurons contributes to mechanical hypersensitivity following peripheral nerve injury.

PubMed

Pang, Rui-Ping; Xie, Man-Xiu; Yang, Jie; Shen, Kai-Feng; Chen, Xi; Su, Ying-Xue; Yang, Chao; Tao, Jing; Liang, Si-Jia; Zhou, Jia-Guo; Zhu, He-Quan; Wei, Xu-Hong; Li, Yong-Yong; Qin, Zhi-Hai; Liu, Xian-Guo

2016-11-01

ClC-3 chloride channel/antiporter has been demonstrated to play an important role in synaptic transmission in central nervous system. However, its expression and function in sensory neurons is poorly understood. In present work, we found that ClC-3 is expressed at high levels in dorsal root ganglia (DRG). Co-immunofluorescent data showed that ClC-3 is mainly distributed in A- and C-type nociceptive neurons. ClC-3 expression in DRG is decreased in the spared nerve injury (SNI) model of neuropathic pain. Knockdown of local ClC-3 in DRG neurons with siRNA increased mechanical sensitivity in naïve rats, while overexpression of ClC-3 reversed the hypersensitivity to mechanical stimuli after peripheral nerve injury. In addition, genetic deletion of ClC-3 enhances mouse mechanical sensitivity but did not affect thermal and cold threshold. Restoration of ClC-3 expression in ClC-3 deficient mice reversed the mechanical sensitivity. Mechanistically, loss of ClC-3 enhanced mechanical sensitivity through increasing the excitability of DRG neurons. These data indicate that ClC-3 is an endogenous inhibitor of neuropathic pain development. Downregulation of ClC-3 by peripheral nerve injury is critical for mechanical hypersensitivity. Our findings suggest that ClC-3 is a novel therapeutic target for treating neuropathic pain. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Substance P and/or calcitonin gene-related peptide immunoreactive neurons in dorsal root ganglia possibly involved in the transmission of nociception in rat penile frenulum].

PubMed

Wu, Zhong-Min; Ni, Jing-Jing; Ling, Shu-Cai

2007-12-01

To study the relationship between substance P (SP) and/or calcitonin gene-related peptide (CGRP) immunoreactive neurons in dorsal root ganglia (DRG) and the transmission of nociception in the penile frenulum of rats. The fluoro-gold (FG) retrograde tracing method was used to trace the origin of nerve terminals in the penile frenulum of rats. And SP and/or CGRP immunofluorescence labeling was employed to detect the distribution of SP and/or CGRP immunoreactive neurons in DRG. FG retrograde tracing showed that the FG retrolabeled neurons were localized in L6-DRG and S1-DRG. SP and/or CGRP immunofluorescence labeling indicated that a large number of DRG neurons were SP- and CGRP-immunoreactive, different in size, bright red and bright green respectively in color, and arranged in rows or spots among nerve bundles. All the FG/SP and FG/CGRP double-labeled neurons were medium or small-sized. One third of the FG-labeled neurons were SP-immunoreactive, and a half of them CGRP-immunoreactive in L6-DRG and S1-DRG respectively. The FG/SP/CGRP-labeled neurons accounted for one fifth of the FG retro labeled neurons. SP- and CGRP-immunoreactive neurons in L6-DRG and SI-DRG of rats may be involved in the transmission of nociception in rat penile frenulum.

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.

Caspase-2 and microRNA34a/c regulate lidocaine-induced dorsal root ganglia apoptosis in vitro.

PubMed

Li, Yandong; Jia, Zhi; Zhang, Laizhu; Wang, Jianguo; Yin, Guangming

2015-11-15

Epidural administration of lidocaine may cause neurotoxicity in spinal cord dorsal root ganglia neurons (DRGNs). In this study, we explored the underling mechanisms of apoptotic pathways of lidocaine-induced apoptosis in DRGNs. Neonatal rat DRGNs were treated with lidocaine to induced apoptosis in vitro. Western blot showed caspase- (casp-) 2/3/9 proteins were all upregulated by lidocaine in DRGNs. However, inhibition of casp-2 protected lidocaine-induced apoptosis in DRGNs, whereas Casp3/9 inhibition did not. The possible upstream epigenetic regulators of casp-2, microRNA-34 (miR-34) family, including miR-34a/b/c, were evaluated by dual-luciferase reporter assay and qRT-PCR. We found miR-34a/c, but not miR-34b, were down-regulated in lidocaine-induced DRGN apoptosis. Subsequent upregulation of miR-34 family showed miR-34a/c were able to inhibit casp-2 and protect lidocaine-induced apoptosis in DRGNs, whereas miR-34b did not. Thus, out study shows that casp-2, in association with miR-34a/c was actively involved in lidocaine-induced apoptosis in DRGNs. Inhibiting casp-2 or upregulating miR-34a/c may provide novel meanings to protect local anesthetic-induced neurotoxicity. Copyright © 2015. Published by Elsevier B.V.

Effective gene expression in the rat dorsal root ganglia with a non-viral vector delivered via spinal nerve injection

PubMed Central

Chang, Ming-Fong; Hsieh, Jung-Hsien; Chiang, Hao; Kan, Hung-Wei; Huang, Cho-Min; Chellis, Luke; Lin, Bo-Shiou; Miaw, Shi-Chuen; Pan, Chun-Liang; Chao, Chi-Chao; Hsieh, Sung-Tsang

2016-01-01

Delivering gene constructs into the dorsal root ganglia (DRG) is a powerful but challenging therapeutic strategy for sensory disorders affecting the DRG and their peripheral processes. The current delivery methods of direct intra-DRG injection and intrathecal injection have several disadvantages, including potential injury to DRG neurons and low transfection efficiency, respectively. This study aimed to develop a spinal nerve injection strategy to deliver polyethylenimine mixed with plasmid (PEI/DNA polyplexes) containing green fluorescent protein (GFP). Using this spinal nerve injection approach, PEI/DNA polyplexes were delivered to DRG neurons without nerve injury. Within one week of the delivery, GFP expression was detected in 82.8% ± 1.70% of DRG neurons, comparable to the levels obtained by intra-DRG injection (81.3% ± 5.1%, p = 0.82) but much higher than those obtained by intrathecal injection. The degree of GFP expression by neurofilament(+) and peripherin(+) DRG neurons was similar. The safety of this approach was documented by the absence of injury marker expression, including activation transcription factor 3 and ionized calcium binding adaptor molecule 1 for neurons and glia, respectively, as well as the absence of behavioral changes. These results demonstrated the efficacy and safety of delivering PEI/DNA polyplexes to DRG neurons via spinal nerve injection. PMID:27748450

Development of a spontaneously active dorsal root ganglia assay using multiwell multielectrode arrays

PubMed Central

Newberry, Kim; Wang, Shuya; Hoque, Nina; Kiss, Laszlo; Ahlijanian, Michael K.; Herrington, James

2016-01-01

In vitro phenotypic assays of sensory neuron activity are important tools for identifying potential analgesic compounds. These assays are typically characterized by hyperexcitable and/or abnormally, spontaneously active cells. Whereas manual electrophysiology experiments provide high-resolution biophysical data to characterize both in vitro models and potential therapeutic modalities (e.g., action potential characteristics, the role of specific ion channels, and receptors), these techniques are hampered by their low throughput. We have established a spontaneously active dorsal root ganglia (DRG) platform using multiwell multielectrode arrays (MEAs) that greatly increase the ability to evaluate the effects of multiple compounds and conditions on DRG excitability within the context of a cellular network. We show that spontaneous DRG firing can be attenuated with selective Na+ and Ca2+ channel blockers, as well as enhanced with K+ channel blockers. In addition, spontaneous activity can be augmented with both the transient receptor potential cation channel subfamily V member 1 agonist capsaicin and the peptide bradykinin and completely blocked with neurokinin receptor antagonists. Finally, we validated the use of this assay by demonstrating that commonly used neuropathic pain therapeutics suppress DRG spontaneous activity. Overall, we have optimized primary rat DRG cells on a multiwell MEA platform to generate and characterize spontaneously active cultures that have the potential to be used as an in vitro phenotypic assay to evaluate potential therapeutics in rodent models of pain. PMID:27052585

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

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

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.

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.

Rapid constitutive and ligand-activated endocytic trafficking of P2X receptor.

PubMed

Vacca, Fabrizio; Giustizieri, Michela; Ciotti, Maria Teresa; Mercuri, Nicola Biagio; Volonté, Cinzia

2009-05-01

P2X receptors mediate a variety of physiological actions, including smooth muscle contraction, neuro-endocrine secretion and synaptic transmission. Among P2X receptors, the P2X(3) subtype is expressed in sensory neurons of dorsal root- and trigeminal-ganglia, where it performs a well-recognized role in sensory and pain transmission. Recent evidence indicates that the strength of P2X(3)-mediated responses is modulated in vivo by altering the number of receptors at the plasma membrane. In the present study, we investigate the trafficking properties of P2X(3) receptor in transfected HEK293 cells and in primary cultures of dorsal root ganglion neurons, finding that P2X(3) receptor undergoes rapid constitutive and cholesterol-dependent endocytosis. We also show that endocytosis is accompanied by preferential targeting of the receptor to late endosomes/lysosomes, with subsequent degradation. Furthermore, we observe that at steady state the receptor localizes predominantly in lamp1-positive intracellular structures, with a minor fraction present at the plasma membrane. Finally, the level of functional receptor expressed on the cell surface is rapidly up-regulated in response to agonist stimulation, which also augments receptor endocytosis. The findings presented in this work underscore a very dynamic trafficking behavior of P2X(3) receptor and disclose a possible mechanism for the rapid modulation of ATP-mediated responses potentially relevant during physiological and pathological conditions.

The Characterization of AT1 Expression in the Dorsal Root Ganglia After Chronic Constriction Injury.

PubMed

Oroszova, Zuzana; Hricova, Ludmila; Stropkovska, Andrea; Lukacova, Nadezda; Pavel, Jaroslav

2017-04-01

To clarify the role of Angiotensin II in the regulation of sensory signaling, we characterized the AT 1 expression in neuronal subpopulation of lower lumbar dorsal root ganglia under normal conditions and its alteration in neuropathic pain model. The characterization of AT 1 expression was done under control and after the chronic constriction injury induced by four loose ligatures of the sciatic nerve representing the model of posttraumatic painful peripheral neuropathy. Major Angiotensin II receptor type was expressed in approximately 43 % of small-sized and 62 % of large-sized neurons in control. The AT 1 overexpression after sciatic nerve ligation lasting 7 days was detected predominantly in small-sized AT 1 immunoreactive neurons (about 38 % increase). Chronic constriction injury caused a statistically marked increase in number of the small-sized peptidergic (CGRP immunoreactive) neuronal subpopulation expressing AT 1 (about 64 %). The subpopulations of AT 1 -immunoreactive and nonpeptide-containing primary sensory neurons revealed by IB4 binding, tyrosine hydroxylase- and parvalbumin-immunoreactive neurons were not markedly changed. Our results indicate that: (1) the AT 1 overexpression after the chronic constriction injury is an important factor in Angiotensin II-potentiated pain perception; (2) Angiotensin II is involved in pathological mechanisms of neuropathic pain and this effect can be mediated perhaps in combination with other neuropeptides synthesized in the primary sensory neurons.

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

Fish oil concentrate delays sensitivity to thermal nociception in mice

PubMed Central

Veigas, Jyothi M.; Williams, Paul J.; Halade, Ganesh; Rahman, Mizanur M.; Yoneda, Toshiyuki; Fernandes, Gabriel

2011-01-01

Fish oil has been used to alleviate pain associated with inflammatory conditions such as rheumatoid arthritis. The anti-inflammatory property of fish oil is attributed to the n-3 fatty acids docosahexaenoic acid and eicosapentaenoic acid. Contrarily, vegetable oils such as safflower oil are rich in n-6 fatty acids which are considered to be mediators of inflammation. This study investigates the effect of n-3 and n-6 fatty acids rich oils as dietary supplements on the thermally induced pain sensitivity in healthy mice. C57Bl/6J mice were fed diet containing regular fish oil, concentrated fish oil formulation (CFO) and safflower oil (SO) for 6 months. Pain sensitivity was measured by plantar test and was correlated to the expression of acid sensing ion channels (ASICs), transient receptor potential vanilloid 1 (TRPV1) and c-fos in dorsal root ganglion cells. Significant delay in sensitivity to thermal nociception was observed in mice fed CFO compared to mice fed SO (p<0.05). A significant diminution in expression of ion channels such as ASIC1a (64%), ASIC13 (37%) and TRPV1 (56%) coupled with reduced expression of c-fos, a marker of neuronal activation, was observed in the dorsal root ganglion cells of mice fed CFO compared to that fed SO. In conclusion, we describe here the potential of fish oil supplement in reducing sensitivity to thermal nociception in normal mice. PMID:21345372

Real-time control of walking using recordings from dorsal root ganglia.

PubMed

Holinski, B J; Everaert, D G; Mushahwar, V K; Stein, R B

2013-10-01

The goal of this study was to decode sensory information from the dorsal root ganglia (DRG) in real time, and to use this information to adapt the control of unilateral stepping with a state-based control algorithm consisting of both feed-forward and feedback components. In five anesthetized cats, hind limb stepping on a walkway or treadmill was produced by patterned electrical stimulation of the spinal cord through implanted microwire arrays, while neuronal activity was recorded from the DRG. Different parameters, including distance and tilt of the vector between hip and limb endpoint, integrated gyroscope and ground reaction force were modelled from recorded neural firing rates. These models were then used for closed-loop feedback. Overall, firing-rate-based predictions of kinematic sensors (limb endpoint, integrated gyroscope) were the most accurate with variance accounted for >60% on average. Force prediction had the lowest prediction accuracy (48 ± 13%) but produced the greatest percentage of successful rule activations (96.3%) for stepping under closed-loop feedback control. The prediction of all sensor modalities degraded over time, with the exception of tilt. Sensory feedback from moving limbs would be a desirable component of any neuroprosthetic device designed to restore walking in people after a spinal cord injury. This study provides a proof-of-principle that real-time feedback from the DRG is possible and could form part of a fully implantable neuroprosthetic device with further development.

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.

Electroacupuncture Reduces Carrageenan- and CFA-Induced Inflammatory Pain Accompanied by Changing the Expression of Nav1.7 and Nav1.8, rather than Nav1.9, in Mice Dorsal Root Ganglia.

PubMed

Huang, Chun-Ping; Chen, Hsiang-Ni; Su, Hong-Lin; Hsieh, Ching-Liang; Chen, Wei-Hsin; Lai, Zhen-Rung; Lin, Yi-Wen

2013-01-01

Several voltage-gated sodium channels (Navs) from nociceptive nerve fibers have been identified as important effectors in pain signaling. The objective of this study is to investigate the electroacupuncture (EA) analgesia mechanism by changing the expression of Navs in mice dorsal root ganglia (DRG). We injected carrageenan and complete Freund's adjuvant (CFA) into the mice plantar surface of the hind paw to induce inflammation and examined the antinociception effect of EA at the Zusanli (ST36) acupoint at 2 Hz low frequency. Mechanical hyperalgesia was evaluated by using electronic von Frey filaments, and thermal hyperalgesia was assessed using Hargreaves' test. Furthermore, we observed the expression and quality of Navs in DRG neurons. Our results showed that EA reduced mechanical and thermal pain in inflammatory animal model. The expression of Nav1.7 and Nav1.8 was increased after 4 days of carrageenan- and CFA-elicited inflammatory pain and further attenuated by 2 Hz EA stimulation. The attenuation cannot be observed in Nav1.9 sodium channels. We demonstrated that EA at Zusanli (ST36) acupoint at 2 Hz low-frequency stimulation attenuated inflammatory pain accompanied by decreasing the expression of Nav1.7 and 1.8, rather than Nav1.9, sodium channels in peripheral DRG neurons.

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.

Peptidomics and Secretomics of the Mammalian Peripheral Sensory-Motor System

NASA Astrophysics Data System (ADS)

Tillmaand, Emily G.; Yang, Ning; Kindt, Callie A. C.; Romanova, Elena V.; Rubakhin, Stanislav S.; Sweedler, Jonathan V.

2015-12-01

The dorsal root ganglion (DRG) and its anatomically and functionally associated spinal nerve and ventral and dorsal roots are important components of the peripheral sensory-motor system in mammals. The cells within these structures use a number of peptides as intercellular signaling molecules. We performed a variety of mass spectrometry (MS)-based characterizations of peptides contained within and secreted from these structures, and from isolated and cultured DRG cells. Liquid chromatography-Fourier transform MS was utilized in DRG and nerve peptidome analysis. In total, 2724 peptides from 296 proteins were identified in tissue extracts. Neuropeptides are among those detected, including calcitonin gene-related peptide I, little SAAS, and known hemoglobin-derived peptides. Solid phase extraction combined with direct matrix-assisted laser desorption/ionization time-of-flight MS was employed to investigate the secretome of these structures. A number of peptides were detected in the releasate from semi-intact preparations of DRGs and associated nerves, including neurofilament- and myelin basic protein-related peptides. A smaller set of analytes was observed in releasates from cultured DRG neurons. The peptide signals observed in the releasates have been mass-matched to those characterized and identified in homogenates of entire DRGs and associated nerves. This data aids our understanding of the chemical composition of the mammalian peripheral sensory-motor system, which is involved in key physiological functions such as nociception, thermoreception, itch sensation, and proprioception.

Peptidomics and Secretomics of the Mammalian Peripheral Sensory-Motor System.

PubMed

Tillmaand, Emily G; Yang, Ning; Kindt, Callie A C; Romanova, Elena V; Rubakhin, Stanislav S; Sweedler, Jonathan V

2015-12-01

The dorsal root ganglion (DRG) and its anatomically and functionally associated spinal nerve and ventral and dorsal roots are important components of the peripheral sensory-motor system in mammals. The cells within these structures use a number of peptides as intercellular signaling molecules. We performed a variety of mass spectrometry (MS)-based characterizations of peptides contained within and secreted from these structures, and from isolated and cultured DRG cells. Liquid chromatography-Fourier transform MS was utilized in DRG and nerve peptidome analysis. In total, 2724 peptides from 296 proteins were identified in tissue extracts. Neuropeptides are among those detected, including calcitonin gene-related peptide I, little SAAS, and known hemoglobin-derived peptides. Solid phase extraction combined with direct matrix-assisted laser desorption/ionization time-of-flight MS was employed to investigate the secretome of these structures. A number of peptides were detected in the releasate from semi-intact preparations of DRGs and associated nerves, including neurofilament- and myelin basic protein-related peptides. A smaller set of analytes was observed in releasates from cultured DRG neurons. The peptide signals observed in the releasates have been mass-matched to those characterized and identified in homogenates of entire DRGs and associated nerves. This data aids our understanding of the chemical composition of the mammalian peripheral sensory-motor system, which is involved in key physiological functions such as nociception, thermoreception, itch sensation, and proprioception.

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.

[Expression and significance of p75NTR in dorsal root ganglia in different injury models].

PubMed

Li, Fang; Cai, Yan; Zhang, Jian-Yi

2008-12-01

To determine the expression and significance of p75NTR in the neuron and glia of dorsal root ganglia (DRG) in different injury models. The models of sciatic nerve injury, spinal cord injury, and combined injury (sciatic nerve injury one week prior to spinal cord injury) were established. The rats were randomly divided into a normal group,a sciatic nerve injury group,a spinal cord injury group, and a combined injury group. The sensory neurons in the DRG were labeled by fast blue (FB) injected in the dorsal column of spinal cord 0.5mm rostral to the transection site. The expression of p75NTR in the neurons and glia of the DRG was examined with immunofluorescence histochemistry after different kinds of injury and its expression in the FB positive neurons was further observed with immunofluorescence histochemistry combined with FB retrograde labeling. The expression of p75NTR was increased in the glia, but was downregulated in sensory neurons in the sciatic nerve injury group compared with the normal group. p75NTR immunoreactive products were downregulated in the glia in the spinal cord injury group compared with the sciatic nerve injury group or the combined injury group. In the combined lesion animals, the expression of p75NTR was similar to that of the sciatic nerve injury group. Its expression in the sensory neurons of DRG was downregulated,but was upregulated in the glia. The majority of sensory neurons labeled by FB in the combined injury group were p75NTR-negative, but surrounded by p75NTR-positive glia. p75NTR immunoreactive products in the glia and neurons of DRG have significant discrepancy after injury. The glial p75NTR in the DRG may play a role in the enhanced regeneration of acsending tract in the injured spinal cord after combined injury.

Relevant Anatomy, Morphology, and Implantation Techniques of the Dorsal Root Ganglia at the Lumbar Levels.

PubMed

Vancamp, Tim; Levy, Robert M; Peña, Isaac; Pajuelo, Antonio

2017-10-01

While dorsal root ganglion (DRG) stimulation has been available in Europe and Australia for the past five years and in the United States for the past year, there are no published details concerning the optimal procedures for DRG lead implantation. We describe several techniques that can be applied to implant cylindrical leads over the DRG, highlighting some tips and tricks according to our experiences. Focus is mainly shifted toward implantations in the lumbar area. We furthermore give some insights in the results we experienced in Spain as well as some worldwide numbers. A 14-gauge needle is placed using a "2-Level Technique (2-LT)" or exceptionally a "1-Level Technique (1-LT)" or a "Primary- or Secondary Technique" at the level of L5. The delivery sheath, loaded with the lead, is advanced toward the targeted neural foramen. The lead is placed over the dorsal aspect of the DRG. A strain relief loop is created in the epidural space. Sheath and needle are retracted and the lead is secured using an anchor or anchorless technique. In Spain, 87.2% (N = 78) of the selected patients have been successfully implanted. Seven (8.9%) had a negative trial and three (4.2%) were explanted. Average VAS score decreased from 8.8 to 3.3 and on average 94.5% of the pain area was covered. In our center's subjects (N = 47 patients, 60.3% of all implanted patients in Spain), VAS scores decreased from an average of 8.8-1.7 and pain coverage averaged 96.4%. We used an average of 1.8 electrodes. Worldwide more than 4000 permanent cases have been successfully performed. We present implantation techniques whereby a percutaneous lead is placed over the DRG through the use of a special designed delivery sheath. Further investigation of the safety, efficacy, and sustainability of clinical outcomes using these devices is warranted. © 2017 International Neuromodulation Society.

Src family kinases mediate the inhibition of substance P release in the rat spinal cord by μ-opioid receptors and GABA(B) receptors, but not α2 adrenergic receptors.

PubMed

Zhang, Guohua; Chen, Wenling; Marvizón, Juan Carlos G

2010-09-01

GABA(B) , μ-opioid and adrenergic α(2) receptors inhibit substance P release from primary afferent terminals in the dorsal horn. Studies in cell expression systems suggest that μ-opioid and GABA(B) receptors inhibit transmitter release from primary afferents by activating Src family kinases (SFKs), which then phosphorylate and inhibit voltage-gated calcium channels. This study investigated whether SFKs mediate the inhibition of substance P release by these three receptors. Substance P release was measured as neurokinin 1 receptor (NK1R) internalization in spinal cord slices and in vivo. In slices, NK1R internalization induced by high-frequency dorsal root stimulation was inhibited by the μ-opioid agonist DAMGO and the GABA(B) agonist baclofen. This inhibition was reversed by the SFK inhibitor PP1. NK1R internalization induced by low-frequency stimulation was also inhibited by DAMGO, but PP1 did not reverse this effect. In vivo, NK1R internalization induced by noxious mechanical stimulation of the hind paw was inhibited by intrathecal DAMGO and baclofen. This inhibition was reversed by intrathecal PP1, but not by the inactive PP1 analog PP3. PP1 produced no effect by itself. The α(2) adrenergic agonists medetomidine and guanfacine produced a small but statistically significant inhibition of NK1R internalization induced by low-frequency dorsal root stimulation. PP1 did not reverse the inhibition by guanfacine. These results show that SFKs mediate the inhibition of substance P release by μ-opioid and GABA(B) receptors, but not by α(2) receptors, which is probably mediated by the binding of G protein βγ subunits to calcium channels. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd. No claim to original US government works.

The distribution and origin of a novel brain peptide, neuropeptide Y, in the spinal cord of several mammals.

PubMed

Gibson, S J; Polak, J M; Allen, J M; Adrian, T E; Kelly, J S; Bloom, S R

1984-07-20

The distribution of neuropeptide Y [NPY]-immunoreactive material was examined in the spinal cord and dorsal root ganglia of rat, guinea-pig, cat, marmoset, and horse. Considerable concentrations of NPY and similar distribution patterns of immunoreactive nerve fibres were found in the spinal cord of all species investigated. The dorsal root ganglia of the cat and the horse contained numerous immunoreactive nerve fibres, but in these species, as in the other three studied [rat, guinea-pig, marmoset], no positively stained cell bodies were found. Neuropeptide Y-immunoreactive nerves were observed at all levels of the spinal cord, being most concentrated in the dorsal horn. In the rat, guinea-pig, and marmoset, there was a marked increase of NPY-immunoreactive fibres in the lumbosacral regions of the spinal cord, and this was reflected by a considerable increase of extractable NPY. Estimations of NPY-immunoreactive material in the various regions of the rat spinal cord were as follows: cervical, 13.8 +/- 1.0; thoracic, 21.1 +/- 2.5; lumbar, 16.3 +/- 2.9; sacral, 92.4 +/- 8.5 pmol/gm wet weight of tissue +/- SEM. In the ventral portion of the guinea-pig spinal cord they were as follows: cervical, 7.1 +/- 1.2; thoracic, 8.2 +/- 3.6; lumbar, 22.6 +/- 7.0; sacral, 36.7 +/- 9.5 pmol/gm wet weight of tissue +/- SEM. Analysis of spinal cord extracts by reverse phase high performance liquid chromatography [HPLC] demonstrated that NPY-immunoreactive material elutes in the position of pure NPY standard. No changes in the concentration and distribution of the NPY-like material in the rat spinal cord were observed following a variety of surgical and pharmacological manipulations, including cervical rhizotomy, sciatic nerve section and ligation, and local application of capsaicin [50 mM] to one sciatic nerve. It is therefore suggested that most of the NPY-immunoreactive material in the spinal cord is derived either from intrinsic nerve cell bodies or from supraspinal tracts.

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.

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

UNMEDULLATED FIBERS ORIGINATING IN DORSAL ROOT GANGLIA

PubMed Central

Gasser, Herbert S.

1950-01-01

The compound action potential of the unmedullated fibers arising from dorsal root ganglia, as recorded in cat skin nerves after conduction of simultaneously initiated impulses, shows among its components a temporal dispersion corresponding to velocities between 2.3 and 0.7 M.P.S. The maximum representation of the component velocities is at about 1.2 M.P.S. On both sides of the maximum the representation falls off irregularly, in such a way that groupings in the distribution produce in the action potential a configuration in which successive features appear always in the same positions at a given conduction distance. Through this demonstration of a characteristic configuration the system of the unmedullated fibers is brought into analogy with that of the medullated fibers. The unmedullated fibers originating in the dorsal root ganglia have distinctive physiological properties, among which is a large positive potential which reaches its maximum immediately after the spike and decrements to half relaxation in about 50 msec., at 37°C. The positive phases of the unit potentials in the compound action potential, owing to their duration, sum to a much greater extent than the temporally dispersed spikes; and, since they have sizes such that one equivalent to 25 per cent of the spike height would not be at the limit, in the summation process the major portion of the compound action potential is caused to be written at a potential level positive to the starting base line. The position of the spikes in the sequence can be seen in the analyses in Section III. The course of the activity in unit fibers is subject to variation in ways affecting the positive potential. Preliminary descriptions, based on orienting experiments, of how these variations are conditioned are given in Section I. Two of the findings are particularly noteworthy. One is the high sensitivity of the dimensions of the postspike positivity to temperature in the range of temperatures at which skin nerves may be expected to function, even when the environmental temperatures of an animal are moderate. The other is the high sensitivity to conditioning by previous activity. The positivity is first decreased, then replaced by a negative potential of similar duration. Reasons have been given why it is inadvisable at the present time to call the postspike potential an after-potential. A comparison has been made of the properties of the unmedullated fibers arising from dorsal root ganglia with those of fibers arising from sympathetic ganglia. The differences are so great that, in the interest of precision in designation, a division of the C group of fibers into two subgroups is indicated. It is suggested that the two subgroups be named respectively d.r.C and s.C. Measurements have been made of the diameters of the d.r.C fibers in a saphenous nerve stained with silver. Graphs showing the number of fibers at each diameter are presented in Section II. In Section III there are shown constructions, from histological data, of the action potential as it would appear, after 3 cm. of conduction, with the correlation between diameter and velocity in strict linearity. The degree of fit between the constructed and recorded potentials can be seen in Fig. 18. PMID:15428610

Auxin effects on Pb phytoextraction from polluted soils by Tegetes minuta L. and Bidens pilosa L.: Extractive power of their root exudates.

PubMed

Salazar, María Julieta; Rodriguez, Judith Hebelen; Cid, Carolina Vergara; Pignata, María Luisa

2016-07-05

The principal impediment for Pb uptake by plants is the Casparian strip in roots. It prevents metals reaching the xylem, thereby hampering translocation to the aerial organs. In the root apices, young root cells have thin cell walls and the Casparian strip is not completely developed, which could facilitate Pb uptake by roots at these vulnerable points. However, as the phytotoxic effects of Pb reduce root growth and enhance suberization, entry of Pb into the plant is avoided. We propose that the application of root growth promotors could be an important complement in the phytoextraction of Pb from polluted soils, due to their effects on produced biomass, Pb toxicity, and root exudate production. A greenhouse experiment was carried on to evaluate the auxin application effect on the Pb uptake of Bidens pilosa and Tagetes minuta. These species were sensitive to auxins, but the phytotoxic effect of Pb was not reversed by this treatment. Root exudates capable of extracting Pb were produced only when the species were grown in highly polluted soils, indicating a behavioral response to Pb exposure which is desirable for phytoremediation. Copyright © 2016 Elsevier B.V. All rights reserved.

Innervation of the rabbit cardiac ventricles.

PubMed

Pauziene, Neringa; Alaburda, Paulius; Rysevaite-Kyguoliene, Kristina; Pauza, Audrys G; Inokaitis, Hermanas; Masaityte, Aiste; Rudokaite, Gabriele; Saburkina, Inga; Plisiene, Jurgita; Pauza, Dainius H

2016-01-01

The rabbit is widely used in experimental cardiac physiology, but the neuroanatomy of the rabbit heart remains insufficiently examined. This study aimed to ascertain the architecture of the intrinsic nerve plexus in the walls and septum of rabbit cardiac ventricles. In 51 rabbit hearts, a combined approach involving: (i) histochemical acetylcholinesterase staining of intrinsic neural structures in total cardiac ventricles; (ii) immunofluorescent labelling of intrinsic nerves, nerve fibres (NFs) and neuronal somata (NS); and (iii) transmission electron microscopy of intrinsic ventricular nerves and NFs was used. Mediastinal nerves access the ventral and lateral surfaces of both ventricles at a restricted site between the root of the ascending aorta and the pulmonary trunk. The dorsal surface of both ventricles is supplied by several epicardial nerves extending from the left dorsal ganglionated nerve subplexus on the dorsal left atrium. Ventral accessing nerves are thicker and more numerous than dorsal nerves. Intrinsic ventricular NS are rare on the conus arteriosus and the root of the pulmonary trunk. The number of ventricular NS ranged from 11 to 220 per heart. Four chemical phenotypes of NS within ventricular ganglia were identified, i.e. ganglionic cells positive for choline acetyltransferase (ChAT), neuronal nitric oxide synthase (nNOS), and biphenotypic, i.e. positive for both ChAT/nNOS and for ChAT/tyrosine hydroxylase. Clusters of small intensely fluorescent cells are distributed within or close to ganglia on the root of the pulmonary trunk, but not on the conus arteriosus. The largest and most numerous intrinsic nerves proceed within the epicardium. Scarce nerves were found near myocardial blood vessels, but the myocardium contained only a scarce meshwork of NFs. In the endocardium, large numbers of thin nerves and NFs proceed along the bundle of His and both its branches up to the apex of the ventricles. The endocardial meshwork of fine NFs was approximately eight times denser than the myocardial meshwork. Adrenergic NFs predominate considerably in all layers of the ventricular walls and septum, whereas NFs of other neurochemical phenotypes were in the minority and their amount differed between the epicardium, myocardium and endocardium. The densities of NFs positive for nNOS and ChAT were similar in the epicardium and endocardium, but NFs positive for nNOS in the myocardium were eight times more abundant than NFs positive for ChAT. Potentially sensory NFs positive for both calcitonin gene-related peptide and substance P were sparse in the myocardial layer, but numerous in epicardial nerves and particularly abundant within the endocardium. Electron microscopic observations demonstrate that intrinsic ventricular nerves have a distinctive morphology, which may be attributed to remodelling of the peripheral nerves after their access into the ventricular wall. In conclusion, the rabbit ventricles display complex structural organization of intrinsic ventricular nerves, NFs and ganglionic cells. The results provide a basic anatomical background for further functional analysis of the intrinsic nervous system in the cardiac ventricles. © 2015 Anatomical Society.

Effectiveness of a computer-aided neuroanatomy program for entry-level physical therapy students: anatomy and clinical examination of the dorsal column-medial lemniscal system.

PubMed

McKeough, D Michael; Mattern-Baxter, Katrin; Barakatt, Edward

2010-01-01

The purpose of this study was to determine if a computer-aided instruction learning module improves students' knowledge of the neuroanatomy/physiology and clinical examination of the dorsal column-medial lemniscal (DCML) system. Sixty-one physical therapy students enrolled in a clinical neurology course in entry-level PT educational programs at two universities participated in the study. Students from University-1 (U1;) had not had a previous neuroanatomy course, while students from University-2 (U2;) had taken a neuroanatomy course in the previous semester. Before and after working with the learning module, students took a paper-and-pencil test on the neuroanatomy/physiology and clinical examination of the DCML system. Kruskal-Wallis one-way ANOVA and Mann-Whitney tests were used to determine if differences existed between neuroanatomy/physiology examination scores and clinical examination scores before and after taking the learning module, and between student groups based on university attended. For students from U1, neuroanatomy/physiology post-test scores improved significantly over pre-test scores (p < 0.001), while post-test scores of students from U2 did not (p = 0.60). Neuroanatomy/physiology pre-test scores from U2 were significantly better than those from U1 (p < 0.001); there was no significant difference in post-test scores (p = 0.062). Clinical examination pre-test and post-test scores from U2 were significantly better than those from U1 (p < 0.001). Clinical examination post-test scores improved significantly from the pre-test scores for both U1 (p < 0.001) and U2 (p < 0.001).

Effects of cholinergic system of dorsal hippocampus of rats on MK-801 induced anxiolytic-like behavior.

PubMed

Zarrindast, Mohammad Reza; Nasehi, Mohammad; Piri, Morteza; Heidari, Negar

2011-11-14

Some investigations have shown that the glutamate receptors play a critical role in cognitive processes such as learning and anxiety. The possible involvement of the cholinergic system of the dorsal hippocampus in the anxiolytic-like response induced by MK-801, NMDA receptor antagonist, was investigated in the present study. Male Wistar rats were used in the elevated plus maze apparatus to test the parameters: open arm time (%OAT), open arm entries (%OAE), close arm time (%CAT), close arm entries (%CAE) and other exploratory behaviors (locomotor activity, grooming, rearing and defecation) of anxiety-like response. The data indicated that intra-CA1 administration of MK-801 increased %OAT (2μg/rat) and %OAE (1 and 2μg/rat) while decreased %CAT and %CAE and did not alter other exploratory behaviors, indicating an anxiolytic-like effect. Moreover, intra-hippocampal injections of mecamylamine, a cholinergic receptor antagonists (2μg/rat) and scopolamine (4μg/rat), by themselves, 5min before testing, increased %OAT and %OAE but decreased %CAT and %CAE and did not alter locomotor activity and other exploratory behaviors, suggesting an anxiolytic-like effect. On the other hand, intra-CA1 co-administration of an ineffective dose of scopolamine (3μg/rat), but not mecamylamine (1μg/rat), with an ineffective dose of MK-801 (0.5μg/rat) increased %OAT and %OAE and decreased %CAT and %CAE. The data may indicate the possible involvement of the cholinergic system of the CA1 in the anxiolytic-like response induced by MK-801. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Wen-Luo-Tong Prevents Glial Activation and Nociceptive Sensitization in a Rat Model of Oxaliplatin-Induced Neuropathic Pain.

PubMed

Deng, Bo; Jia, Liqun; Pan, Lin; Song, Aiping; Wang, Yuanyuan; Tan, Huangying; Xiang, Qing; Yu, Lili; Ke, Dandan

2016-01-01

One of the main dose-limiting complications of the chemotherapeutic agent oxaliplatin (OXL) is painful neuropathy. Glial activation and nociceptive sensitization may be responsible for the mechanism of neuropathic pain. The Traditional Chinese Medicine (TCM) Wen-luo-tong (WLT) has been widely used in China to treat chemotherapy induced neuropathic pain. However, there is no study on the effects of WLT on spinal glial activation induced by OXL. In this study, a rat model of OXL-induced chronic neuropathic pain was established and WLT was administrated. Pain behavioral tests and morphometric examination of dorsal root ganglia (DRG) were conducted. Glial fibrillary acidic protein (GFAP) immunostaining was performed, glial activation was evaluated, and the excitatory neurotransmitter substance P (SP) and glial-derived proinflammatory cytokine tumor necrosis factor-α (TNF-α) were analyzed. WLT treatment alleviated OXL-induced mechanical allodynia and mechanical hyperalgesia. Changes in the somatic, nuclear, and nucleolar areas of neurons in DRG were prevented. In the spinal dorsal horn, hypertrophy and activation of GFAP-positive astrocytes were averted, and the level of GFAP mRNA decreased significantly. Additionally, TNF-α mRNA and protein levels decreased. Collectively, these results indicate that WLT reversed both glial activation in the spinal dorsal horn and nociceptive sensitization during OXL-induced chronic neuropathic pain in rats.

Xanthofulvin, a novel semaphorin inhibitor produced by a strain of Penicillium.

PubMed

Kumagai, Kazuo; Hosotani, Nobuo; Kikuchi, Kaoru; Kimura, Toru; Saji, Ikutaro

2003-07-01

A new semaphorin inhibitor xanthofulvin was isolated from the cultured broth of a fungus Penicillium sp. SPF-3059 along with a known compound vinaxanthone by solvent extraction and bioassay-guided fractionation. The tautomeric structure of xanthofulvin was determined by spectroscopic analyses. The two compounds exhibited significant semaphorin inhibitory activity with IC50 values of 0.09 and 0.1 microg/ml, respectively, in semaphorin3A-induced growth cone collapse assay using cultured chick dorsal root ganglia neurons.

A neurite quality index and machine vision software for improved quantification of neurodegeneration.

PubMed

Romero, Peggy; Miller, Ted; Garakani, Arman

2009-12-01

Current methods to assess neurodegradation in dorsal root ganglion cultures as a model for neurodegenerative diseases are imprecise and time-consuming. Here we describe two new methods to quantify neuroprotection in these cultures. The neurite quality index (NQI) builds upon earlier manual methods, incorporating additional morphological events to increase detection sensitivity for the detection of early degeneration events. Neurosight is a machine vision-based method that recapitulates many of the strengths of NQI while enabling high-throughput screening applications with decreased costs.

Root Architecture Responses: In Search of Phosphate1

PubMed Central

Kanno, Satomi; Nussaume, Laurent

2014-01-01

Soil phosphate represents the only source of phosphorus for plants and, consequently, is its entry into the trophic chain. This major component of nucleic acids, phospholipids, and energy currency of the cell (ATP) can limit plant growth because of its low mobility in soil. As a result, root responses to low phosphate favor the exploration of the shallower part of the soil, where phosphate tends to be more abundant, a strategy described as topsoil foraging. We will review the diverse developmental strategies that can be observed among plants by detailing the effect of phosphate deficiency on primary and lateral roots. We also discuss the formation of cluster roots: an advanced adaptive strategy to cope with low phosphate availability observed in a limited number of species. Finally, we will put this work into perspective for future research directions. PMID:25341534

Upper-limb muscle responses to epidural, subdural and intraspinal stimulation of the cervical spinal cord

NASA Astrophysics Data System (ADS)

Sharpe, Abigail N.; Jackson, Andrew

2014-02-01

Objective. Electrical stimulation of the spinal cord has potential applications following spinal cord injury for reanimating paralysed limbs and promoting neuroplastic changes that may facilitate motor rehabilitation. Here we systematically compare the efficacy, selectivity and frequency-dependence of different stimulation methods in the cervical enlargement of anaesthetized monkeys. Approach. Stimulating electrodes were positioned at multiple epidural and subdural sites on both dorsal and ventral surfaces, as well as at different depths within the spinal cord. Motor responses were recorded from arm, forearm and hand muscles. Main results. Stimulation efficacy increased from dorsal to ventral stimulation sites, with the exception of ventral epidural electrodes which had the highest recruitment thresholds. Compared to epidural and intraspinal methods, responses to subdural stimulation were more selective but also more similar between adjacent sites. Trains of stimuli delivered to ventral sites elicited consistent responses at all frequencies whereas from dorsal sites we observed a mixture of short-latency facilitation and long-latency suppression. Finally, paired stimuli delivered to dorsal surface and intraspinal sites exhibited symmetric facilitatory interactions at interstimulus intervals between 2-5 ms whereas on the ventral side interactions tended to be suppressive for near-simultaneous stimuli. Significance. We interpret these results in the context of differential activation of afferent and efferent roots and intraspinal circuit elements. In particular, we propose that distinct direct and indirect actions of spinal cord stimulation on motoneurons may be advantageous for different applications, and this should be taken into consideration when designing neuroprostheses for upper-limb function.

Increased thrombospondin-4 after nerve injury mediates disruption of intracellular calcium signaling in primary sensory neurons

PubMed Central

Guo, Yuan; Zhang, Zhiyong; Wu, Hsiang-en; Luo, Z. David; Hogan, Quinn H.; Pan, Bin

2017-01-01

Painful nerve injury disrupts Ca2+ signaling in primary sensory neurons by elevating plasma membrane Ca2+-ATPase (PMCA) function and depressing sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) function, which decreases endoplasmic reticulum (ER) Ca2+ stores and stimulates store-operated Ca2+ entry (SOCE). The extracellular matrix glycoprotein thrombospondin-4 (TSP4), which is increased after painful nerve injury, decreases Ca2+ current (ICa) through high-voltage–activated Ca2+ channels and increases ICa through low-voltage–activated Ca2+ channels in dorsal root ganglion neurons, which are events similar to the effect of nerve injury. We therefore examined whether TSP4 plays a critical role in injury-induced disruption of intracellular Ca2+ signaling. We found that TSP4 increases PMCA activity, inhibits SERCA, depletes ER Ca2+ stores, and enhances store-operated Ca2+ influx. Injury-induced changes of SERCA and PMCA function are attenuated in TSP4 knock-out mice. Effects of TSP4 on intracellular Ca2+ signaling are attenuated in voltage-gated Ca2+ channel α2δ1 subunit (Cavα2δ1) conditional knock-out mice and are also Protein Kinase C (PKC) signaling dependent. These findings suggest that TSP4 elevation may contribute to the pathogenesis of chronic pain following nerve injury by disrupting intracellular Ca2+ signaling via interacting with the Cavα2δ1 and the subsequent PKC signaling pathway. Controlling TSP4 mediated intracellular Ca2+ signaling in peripheral sensory neurons may be a target for analgesic drug development for neuropathic pain. PMID:28232180

Netrin1 establishes multiple boundaries for axon growth in the developing spinal cord.

PubMed

Varadarajan, Supraja G; Butler, Samantha J

2017-10-01

The canonical model for netrin1 function proposed that it acted as a long-range chemotropic axon guidance cue. In the developing spinal cord, floor-plate (FP)-derived netrin1 was thought to act as a diffusible attractant to draw commissural axons to the ventral midline. However, our recent studies have shown that netrin1 is dispensable in the FP for axon guidance. We have rather found that netrin1 acts locally: netrin1 is produced by neural progenitor cells (NPCs) in the ventricular zone (VZ), and deposited on the pial surface as a haptotactic adhesive substrate that guides Dcc + axon growth. Here, we further demonstrate that this netrin1 pial-substrate has an early role orienting pioneering spinal axons, directing them to extend ventrally. However, as development proceeds, commissural axons choose to grow around a boundary of netrin1 expressing cells in VZ, instead of continuing to extend alongside the netrin1 pial-substrate in the ventral spinal cord. This observation suggests netrin1 may supply a more complex activity than pure adhesion, with netrin1-expressing cells also supplying a growth boundary for axons. Supporting this possibility, we have observed that additional domains of netrin1 expression arise adjacent to the dorsal root entry zone (DREZ) in E12.5 mice that are also required to sculpt axonal growth. Together, our studies suggest that netrin1 provides "hederal" boundaries: a local growth substrate that promotes axon extension, while also preventing local innervation of netrin1-expressing domains. Copyright © 2017 Elsevier Inc. All rights reserved.

Water entry for the black locust (Robinia pseudoacacia L.) seeds observed by dedicated micro-magnetic resonance imaging.

PubMed

Koizumi, Mika; Kano, Hiromi

2016-07-01

Water entry at germination for black locust (Robinia pseudoacacia L.) seeds which are known as hard seeds with impermeable seed coat to water, was examined using micro-magnetic resonance imaging (MRI). The MRI apparatus equipped with a low-field (1 T; Tesla) permanent magnet was used, which is open access, easy maintenance, operable and transportable. The excellent point of the apparatus is that T 1-enhancement of water signals absorbed in dry seeds against steeping free water is stronger than the apparatuses with high-field superconducting magnets, which enabled clear detection of water entry. Water hardly penetrated into the seeds for more than 8 h but approximately 60 % of seeds germinated by incubating on wet filter papers for several days. Hot water treatments above 75 °C for 3 min effectively induced water gap; scarification was 70 % at 100 °C and 75 °C, declined to 15 % at 50 °C and decreased further at room temperature. Water entered into the scarified seeds exclusively through the lens, spread along the dorsal side of the seeds and reached the hypocotyl, whereas water migrated slowly through hilum side to radicle within 3 h.

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 Inc. All rights reserved.

HL7 Structured Product Labeling - electronic prescribing information for provider order entry decision support.

PubMed

Schadow, Gunther

2005-01-01

Prescribing errors are an important cause of adverse events, and lack of knowledge of the drug is a root cause for prescribing errors. The FDA is issuing new regulations that will make the drug labels much more useful not only to physicians, but also to computerized order entry systems that support physicians to practice safe prescribing. For this purpose, FDA works with HL7 to create the Structured Product Label (SPL) standard that includes a document format as well as a drug knowledge representation, this poster introduces the basic concepts of SPL.

A construction of unimodular equiangular tight frames from resolvable Steiner systems

NASA Astrophysics Data System (ADS)

Jasper, John

2013-09-01

An equiangular tight frame (ETF) is an M x N matrix which has orthogonal equal norm rows, equal norm columns, and the inner products of all pairs of columns have the same modulus. In this paper we study ETFs in which all of the entries are unimodular, and in particular pth roots of unity. A new construction of unimodular ETFs based on resolvable Steiner systems is presented. This construction gives many new examples of unimodular ETFs. In particular, an new infinite class of ETFs with entries in f1;-1g is presented.

Intraganglionic AAV6 results in efficient and long-term gene transfer to peripheral sensory nervous system in adult rats.

PubMed

Yu, Hongwei; Fischer, Gregory; Ferhatovic, Lejla; Fan, Fan; Light, Alan R; Weihrauch, Dorothee; Sapunar, Damir; Nakai, Hiroyuki; Park, Frank; Hogan, Quinn H

2013-01-01

We previously demonstrated safe and reliable gene transfer to the dorsal root ganglion (DRG) using a direct microinjection procedure to deliver recombinant adeno-associated virus (AAV) vector. In this study, we proceed to compare the in vivo transduction patterns of self-complementary (sc) AAV6 and AAV8 in the peripheral sensory pathway. A single, direct microinjection of either AAV6 or AAV8 expressing EGFP, at the adjusted titer of 2×10(9) viral particle per DRG, into the lumbar (L) 4 and L5 DRGs of adult rats resulted in efficient EGFP expression (48±20% for AAV6 and 25±4% for AAV8, mean ± SD) selectively in sensory neurons and their axonal projections 3 weeks after injection, which remained stable for up to 3 months. AAV6 efficiently transfers EGFP to all neuronal size groups without differential neurotropism, while AAV8 predominantly targets large-sized neurons. Neurons transduced with AAV6 penetrate into the spinal dorsal horn (DH) and terminate predominantly in superficial DH laminae, as well as in the dorsal columns and deeper laminae III-V. Only few AAV8-transduced afferents were evident in the superficial laminae, and spinal EGFP was mostly present in the deeper dorsal horn (lamina III-V) and dorsal columns, with substantial projections to the ventral horn. AAV6-mediated EGFP-positive nerve fibers were widely observed in the medial plantar skin of ipsilateral hindpaws. No apparent inflammation, tissue damage, or major pain behaviors were observed for either AAV serotype. Taken together, both AAV6 and AAV8 are efficient and safe vectors for transgene delivery to primary sensory neurons, but they exhibit distinct functional features. Intraganglionic delivery of AAV6 is more uniform and efficient compared to AAV8 in gene transfer to peripheral sensory neurons and their axonal processes.

A role for protein kinase intracellular messengers in substance P- and nociceptor afferent-mediated excitation and expression of the transcription factor Fos in rat dorsal horn neurons in vitro.

PubMed

Badie-Mahdavi, H; Worsley, M A; Ackley, M A; Asghar, A U; Slack, J R; King, A E

2001-08-01

Expression of the inducible transcription factor Fos in the spinal dorsal horn in vivo is associated with nociceptive afferent activation, but the underlying stimulation-transcription pathway is less clear. This in vitro spinal cord study concerns the role of protein kinase A and C second messengers in substance P receptor (NK1R)-mediated or nociceptive afferent-evoked neuronal excitation and Fos expression. Nociceptive afferent (dorsal root) stimulation of isolated spinal cords (10-14 day old rats) evoked a 'prolonged' excitatory polysynaptic potential (DR-EPSP) that was attenuated (P < 0.05) by: the protein kinase A inhibitor, Rp-cAMP; the protein kinase C inhibitor, bisindolymaleimide I; and the selective NK1R antagonist, GR82334. Neuronal excitations induced by the NK1R agonist [Sar9,Met(O2)11]-SP were attenuated by Rp-cAMP, bisindolymaleimide I and GR82334. Effects of the protein kinase A and C inhibitors on the DR-EPSP or the [Sar9,Met(O2)11]-SP-induced depolarization were nonadditive, suggesting convergence of these intracellular signalling pathways onto a common final target. Nociceptor afferent-induced Fos, detected by immunohistochemistry in superficial and deep dorsal horn laminae, was attenuated by Rp-cAMP, bisindolymaleimide I and GR82334. In spinal cords pretreated with TTX to eliminate indirect neuronal activation, [Sar9,Met(O2)11]-SP (1-20 microM) elicited a dose-related expression of Fos that was reduced by Rp-cAMP, bisindolymaleimide I and GR82334. The effects of these inhibitors were most pronounced in the deep laminae. These data support a causal relationship between protein kinase A- or C-dependent signal transduction, nociceptive afferent- or NK1R-induced neuronal excitation and Fos expression in dorsal horn. Implications for short- versus long-term modulation of nociceptive circuitry are discussed.

Paired motor cortex and cervical epidural electrical stimulation timed to converge in the spinal cord promotes lasting increases in motor responses

PubMed Central

Mishra, Asht M.; Pal, Ajay; Gupta, Disha

2017-01-01

Key points Pairing motor cortex stimulation and spinal cord epidural stimulation produced large augmentation in motor cortex evoked potentials if they were timed to converge in the spinal cord.The modulation of cortical evoked potentials by spinal cord stimulation was largest when the spinal electrodes were placed over the dorsal root entry zone.Repeated pairing of motor cortex and spinal cord stimulation caused lasting increases in evoked potentials from both sites, but only if the time between the stimuli was optimal.Both immediate and lasting effects of paired stimulation are likely mediated by convergence of descending motor circuits and large diameter afferents onto common interneurons in the cervical spinal cord. Abstract Convergent activity in neural circuits can generate changes at their intersection. The rules of paired electrical stimulation are best understood for protocols that stimulate input circuits and their targets. We took a different approach by targeting the interaction of descending motor pathways and large diameter afferents in the spinal cord. We hypothesized that pairing stimulation of motor cortex and cervical spinal cord would strengthen motor responses through their convergence. We placed epidural electrodes over motor cortex and the dorsal cervical spinal cord in rats; motor evoked potentials (MEPs) were measured from biceps. MEPs evoked from motor cortex were robustly augmented with spinal epidural stimulation delivered at an intensity below the threshold for provoking an MEP. Augmentation was critically dependent on the timing and position of spinal stimulation. When the spinal stimulation was timed to coincide with the descending volley from motor cortex stimulation, MEPs were more than doubled. We then tested the effect of repeated pairing of motor cortex and spinal stimulation. Repetitive pairing caused strong augmentation of cortical MEPs and spinal excitability that lasted up to an hour after just 5 min of pairing. Additional physiology experiments support the hypothesis that paired stimulation is mediated by convergence of descending motor circuits and large diameter afferents in the spinal cord. The large effect size of this protocol and the conservation of the circuits being manipulated between rats and humans makes it worth pursuing for recovery of sensorimotor function after injury to the central nervous system. PMID:28752624

Paired motor cortex and cervical epidural electrical stimulation timed to converge in the spinal cord promotes lasting increases in motor responses.

PubMed

Mishra, Asht M; Pal, Ajay; Gupta, Disha; Carmel, Jason B

2017-11-15

Pairing motor cortex stimulation and spinal cord epidural stimulation produced large augmentation in motor cortex evoked potentials if they were timed to converge in the spinal cord. The modulation of cortical evoked potentials by spinal cord stimulation was largest when the spinal electrodes were placed over the dorsal root entry zone. Repeated pairing of motor cortex and spinal cord stimulation caused lasting increases in evoked potentials from both sites, but only if the time between the stimuli was optimal. Both immediate and lasting effects of paired stimulation are likely mediated by convergence of descending motor circuits and large diameter afferents onto common interneurons in the cervical spinal cord. Convergent activity in neural circuits can generate changes at their intersection. The rules of paired electrical stimulation are best understood for protocols that stimulate input circuits and their targets. We took a different approach by targeting the interaction of descending motor pathways and large diameter afferents in the spinal cord. We hypothesized that pairing stimulation of motor cortex and cervical spinal cord would strengthen motor responses through their convergence. We placed epidural electrodes over motor cortex and the dorsal cervical spinal cord in rats; motor evoked potentials (MEPs) were measured from biceps. MEPs evoked from motor cortex were robustly augmented with spinal epidural stimulation delivered at an intensity below the threshold for provoking an MEP. Augmentation was critically dependent on the timing and position of spinal stimulation. When the spinal stimulation was timed to coincide with the descending volley from motor cortex stimulation, MEPs were more than doubled. We then tested the effect of repeated pairing of motor cortex and spinal stimulation. Repetitive pairing caused strong augmentation of cortical MEPs and spinal excitability that lasted up to an hour after just 5 min of pairing. Additional physiology experiments support the hypothesis that paired stimulation is mediated by convergence of descending motor circuits and large diameter afferents in the spinal cord. The large effect size of this protocol and the conservation of the circuits being manipulated between rats and humans makes it worth pursuing for recovery of sensorimotor function after injury to the central nervous system. © 2017 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

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

Resveratrol protects bupivacaine-induced neuro-apoptosis in dorsal root ganglion neurons via activation on tropomyosin receptor kinase A.

PubMed

Guo, Zhiliang; Liu, Yuanyuan; Cheng, Min

2018-07-01

General anesthesia in spinal cord may lead to unexpected but irreversible neurotoxicity. We investigated whether resveratrol (RSV) may protect bupivacaine (BUP)-induced neuro-apoptosis in spinal cord dorsal root ganglia (DRG). Mouse DRG cells were cultured in vitro, pre-treated with RSV and then 5 mM BUP. A concentration-dependent effect of RSV on reducing BUP-induced apoptosis of DRG neurons (DRGNs) was evaluated using a TUNEL assay. QRT-PCR and western blot assays were also conducted to evaluate gene and protein expressions of tropomyosin receptor kinase A/B/C (TrkA/B/C) and activated (phosphorylated) Trk receptors, phospho-TrkA/B/C. In addition, a functional TrkA blocking antibody MNAC13 was applied in DRG culture to further measure the functional role of Trk receptor in RSV-initiated apoptotic protection on BUP-damaged DRGNs. BUP promoted significant apoptosis in DRG. RSV exhibited protective effects against BUP-induced neuro-apoptosis in a concentration-dependent manner. qRT-PCR and western blot showed that RSV did not alter TrkA/B/C gene or protein expression, but significantly upregulated phospho-TrkA. Conversely, application of MNAC13 decreased phospho-TrkA and reversed RSV-initiated neuro-protection on BUP-induced DRGN apoptosis. Resveratrol may protect anesthesia-induced DRG neuro-apoptosis, and activation of TrkA signaling pathway may be the underlying mechanism in this process. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

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.

Collodictyon triciliatum and Diphylleia rotans (=Aulacomonas submarina) form a new family of flagellates (Collodictyonidae) with tubular mitochondrial cristae that is phylogenetically distant from other flagellate groups.

PubMed

Brugerolle, Guy; Bricheux, Geneviève; Philippe, Hervé; Coffea, Gérard

2002-03-01

Comparative electron microscopic studies of Collodictyon triciliatum and Diphylleia rotans (=Aulacomonas submarina) showed that they share a distinctive flagellar transitional zone and a very similar flagellar apparatus. In both species, the basic couple of basal bodies and flagella #1 and #2 are connected to the dorsal and ventral roots, respectively. Collodictyon triciliatum has two additional basal bodies and flagella, #3 and #4, situated on each side of the basic couple, each of which also bears a dorsal root. The horseshoe-shaped arrangement of dictyosomes, mitochondria with tubular cristae and the deep ventral groove are very similar to those of Diphylleia rotans. These two genera have very specific features and are placed in a new family, Collodictyonidae, distinct from other eukaryotic groups. Electron microscopic observation of mitotic telophase in Diphylleia rotans revealed two chromosomal masses, surrounded by the nuclear envelope, within the dividing parental nucleus, as in the telophase stage of the heliozoan Actinophrys and the helioflagellate Dimorpha. Spindle microtubules arise from several MTOCs outside the nucleus, and several microtubules penetrate within the dividing nucleus, via pores at the poles. This semi-open type of orthomitosis is reminiscent of that of actinophryids. The SSU rDNA sequence of Diphylleia rotans was compared with that of all the eukaryotic groups that have a slow-evolving rDNA. Diphylleia did not strongly assemble with any group and emerged in a very poorly resolved part of the eukaryotic phylogenetic tree.

Galectin-3 Inhibition Is Associated with Neuropathic Pain Attenuation after Peripheral Nerve Injury

PubMed Central

Ai, Zisheng; Zheng, Yongjun

2016-01-01

Neuropathic pain remains a prevalent and persistent clinical problem because it is often poorly responsive to the currently used analgesics. It is very urgent to develop novel drugs to alleviate neuropathic pain. Galectin-3 (gal3) is a multifunctional protein belonging to the carbohydrate-ligand lectin family, which is expressed by different cells. Emerging studies showed that gal3 elicits a pro-inflammatory response by recruiting and activating lymphocytes, macrophages and microglia. In the study we investigated whether gal3 inhibition could suppress neuroinflammation and alleviate neuropathic pain following peripheral nerve injury. We found that L5 spinal nerve ligation (SNL) increases the expression of gal3 in dorsal root ganglions at the mRNA and protein level. Intrathecal administration of modified citrus pectin (MCP), a gal3 inhibitor, reduces gal3 expression in dorsal root ganglions. MCP treatment also inhibits SNL-induced gal3 expression in primary rat microglia. SNL results in an increased activation of autophagy that contributes to microglial activation and subsequent inflammatory response. Intrathecal administration of MCP significantly suppresses SNL-induced autophagy activation. MCP also inhibits lipopolysaccharide (LPS)-induced autophagy in cultured microglia in vitro. MCP further decreases LPS-induced expression of proinflammatory mediators including IL-1β, TNF-α and IL-6 by regulating autophagy. Intrathecal administration of MCP results in adecreased mechanical and cold hypersensitivity following SNL. These results demonstrated that gal3 inhibition is associated with the suppression of SNL-induced inflammatory process andneurophathic pain attenuation. PMID:26872020

Morphological Study of the Persian Leopard (Panthera pardus saxicolor) Tongue.

PubMed

Sadeghinezhad, J; Sheibani, M T; Memarian, I; Chiocchetti, R

2017-06-01

This study described the morphological features of the Persian leopard (Panthera pardus saxicolor) tongue using light and scanning electron microscopy techniques. The keratinized filiform papillae were distributed all over the entire dorsal surface of the tongue and contained small processes. They were changed into a cylindrical shape in the body and conical shape in the root. The fungiform papillae were found on the apex and margin of the tongue. Few taste pores were observed on the dorsal surface of each papilla. The foliate papillae on the margins of the tongue were composed of several laminae and epithelial fissures. Taste buds were not seen within the non-keratinized epithelium. The vallate papillae were six in total and arranged in a "V" shape just rostral to the root. Each papilla was surrounded by a groove and pad. Taste buds were seen within their lateral walls. Lyssa was visible on the ventral surface of the tongue tip and was found as cartilaginous tissue surrounded by thin connective tissue fibres. The core of the tongue was composed of lingual glands, skeletal muscle and connective tissue. These glands were confined to the posterior portion of the tongue and were composed of many serous cells and a few mucous cells. The results of this study contributed to the knowledge of the morphological characteristics of the tongue of wild mammals and provided data for the comparison with other mammals. © 2017 Blackwell Verlag GmbH.

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.

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.

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.

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

PubMed Central

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

2016-01-01

Dorsal root ganglia (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. PMID:26383867

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.

Time Course of Substance P Expression in Dorsal Root Ganglia Following Complete Spinal Nerve Transection

PubMed Central

Weissner, Wendy; Winterson, Barbara J.; Stuart-Tilley, Alan; Devor, Marshall; Bove, Geoffrey M.

2008-01-01

Recent evidence suggests that substance P (SP) is upregulated in primary sensory neurons following axotomy, and that this change occurs in larger neurons that do not usually produce SP. If so, this upregulation may allow normally neighboring, uninjured, and non-nociceptive dorsal root ganglion (DRG) neurons to become effective in activating pain pathways. Using immunohistochemistry, we performed a unilateral L5 spinal nerve transection upon male Wistar rats, and measured SP expression in ipsilateral L4 and L5 DRGs and contralateral L5 DRGs, at 1 to 14 days postoperatively (dpo), and in control and sham operated rats. In normal and sham operated DRGs, SP was detectable almost exclusively in small neurons (≤ 800 μm2). Following surgery, the mean size of SP-positive neurons from the axotomized L5 ganglia was greater at 2, 4, 7 and 14 dpo. Among large neurons (> 800 μm2) from the axotomized L5, the percentage of SP-positive neurons increased at 2, 4, 7, and 14 dpo. Among small neurons from the axotomized L5, the percentage of SP-positive neurons was increased at 1 and 3 dpo, but was decreased at 7 and 14 dpo. Thus, SP expression is affected by axonal damage, and the time course of the expression is different between large and small DRG neurons. These data support a role of SP-producing, large DRG neurons in persistent sensory changes due to nerve injury. PMID:16680762

MiR-34a Regulates Axonal Growth of Dorsal Root Ganglia Neurons by Targeting FOXP2 and VAT1 in Postnatal and Adult Mouse.

PubMed

Jia, Longfei; Chopp, Michael; Wang, Lei; Lu, Xuerong; Zhang, Yi; Szalad, Alexandra; Zhang, Zheng Gang

2018-04-10

Hyperglycemia impairs nerve fibers of dorsal root ganglia (DRG) neurons, leading to diabetic peripheral neuropathy (DPN). However, the molecular mechanisms underlying DPN are not fully understood. Using a mouse model of type II diabetes (db/db mouse), we found that microRNA-34a (miR-34a) was over-expressed in DRG, sciatic nerve, and foot pad tissues of db/db mice. In vitro, high glucose significantly upregulated miR-34a in postnatal and adult DRG neurons, which was associated with inhibition of axonal growth. Overexpression and attenuation of miR-34a in postnatal and adult DRG neurons suppressed and promoted, respectively, axonal growth. Bioinformatic analysis suggested that miR-34a putatively targets forkhead box protein P2 (FOXP2) and vesicle amine transport 1 (VAT1), which were decreased in diabetic tissues and in cultured DRG neurons under high glucose conditions. Dual-luciferase assay showed that miR-34a downregulated FOXP2 and VAT1 expression by targeting their 3' UTR. Gain-of- and loss-of-function analysis showed an inverse relation between augmentation of miR-34a and reduction of FOXP2 and VAT1 proteins in postnatal and adult DRG neurons. Knockdown of FOXP2 and VAT1 reduced axonal growth. Together, these findings suggest that miR-34a and its target genes of FOXP2 and VAT1 are involved in DRG neuron damage under hyperglycemia.

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.

Regulate axon branching by the cyclic GMP pathway via inhibition of glycogen synthase kinase 3 in dorsal root ganglion sensory neurons.

PubMed

Zhao, Zhen; Wang, Zheng; Gu, Ying; Feil, Robert; Hofmann, Franz; Ma, Le

2009-02-04

Cyclic GMP has been proposed to regulate axonal development, but the molecular and cellular mechanisms underlying the formation of axon branches are not well understood. Here, we report the use of rodent embryonic sensory neurons from the dorsal root ganglion (DRG) to demonstrate the role of cGMP signaling in axon branching and to identify the downstream molecular pathway mediating this novel regulation. Pharmacologically, a specific cGMP analog promotes DRG axon branching in culture, and this activity can be achieved by activating the endogenous soluble guanylyl cyclase that produces cGMP. At the molecular level, the cGMP-dependent protein kinase 1 (PrkG1) mediates this activity, as DRG neurons isolated from the kinase-deficient mouse fail to respond to cGMP activation to make branches, whereas overexpression of a PrkG1 mutant with a higher-than-normal basal kinase activity is sufficient to induce branching. In addition, cGMP activation in DRG neurons leads to phosphorylation of glycogen synthase kinase 3 (GSK3), a protein that normally suppresses branching. This interaction is direct, because PrkG1 binds GSK3 in heterologous cells and the purified kinase can phosphorylate GSK3 in vitro. More importantly, overexpression of a dominant active form of GSK3 suppresses cGMP-dependent branching in DRG neurons. Thus, our study establishes an intrinsic signaling cascade that links cGMP activation to GSK3 inhibition in controlling axon branching during sensory axon development.

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

Real-time control of walking using recordings from dorsal root ganglia

NASA Astrophysics Data System (ADS)

Holinski, B. J.; Everaert, D. G.; Mushahwar, V. K.; Stein, R. B.

2013-10-01

Objective. The goal of this study was to decode sensory information from the dorsal root ganglia (DRG) in real time, and to use this information to adapt the control of unilateral stepping with a state-based control algorithm consisting of both feed-forward and feedback components. Approach. In five anesthetized cats, hind limb stepping on a walkway or treadmill was produced by patterned electrical stimulation of the spinal cord through implanted microwire arrays, while neuronal activity was recorded from the DRG. Different parameters, including distance and tilt of the vector between hip and limb endpoint, integrated gyroscope and ground reaction force were modelled from recorded neural firing rates. These models were then used for closed-loop feedback. Main results. Overall, firing-rate-based predictions of kinematic sensors (limb endpoint, integrated gyroscope) were the most accurate with variance accounted for >60% on average. Force prediction had the lowest prediction accuracy (48 ± 13%) but produced the greatest percentage of successful rule activations (96.3%) for stepping under closed-loop feedback control. The prediction of all sensor modalities degraded over time, with the exception of tilt. Significance. Sensory feedback from moving limbs would be a desirable component of any neuroprosthetic device designed to restore walking in people after a spinal cord injury. This study provides a proof-of-principle that real-time feedback from the DRG is possible and could form part of a fully implantable neuroprosthetic device with further development.

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.

[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.

Study of the damage rate caused by intervertebral foramen type inside and outside and the pass of the intervertebral DRG RF puncture way.

PubMed

Sun, Jiashu; Zhang, Haitao

2014-09-01

This paper was to analyze and contrast the damage rate on the thoracic segment different position of the dorsal root ganglion(dorsal root ganglion, DRG) caused by different puncture path in radiofrequency ablation, thus the best RF target way for the thoracic segment of different types of DRG was confirmed. According to the difference of puncture and ablation damage way, 14 segmental spinal specimens were randomly divided into three groups, and then conducted DRG radiofrequency damage on percutaneous puncture path according to the type of DRG position.The damage effect of different puncture path by the judgment standard of the result of pathology analyzed. The experiment showed that RF damage of group A were 72.58 ± 18.88%, 54.16 ± 24.84% and 32.85 ± 28.11%; that of group B were 771.86 ± 15.15% and 72.02 ± 17.86%, 57.14 ± 18.02% and 52.47 ± 20.64%, 68.75 ± 14.63% and 71.78 ± 16.00%; and that of group C were 82.46 ± 14.10%, 81.53 ± 11.81% and 80.83 ± 13.33%. It was concluded that the singleness of DRG puncture route is one of the important reasons for the poor thoracic segments DRG radiofrequency (RF) ablation effect. While according to the type of DRG different positions with double joint puncture path can significantly improve the rate of DRG RF damage.

Effect of artemisinin on neuropathic pain mediated by P2X4 receptor in dorsal root ganglia.

PubMed

Ying, Mofeng; Liu, Hui; Zhang, Tengling; Jiang, Chenxu; Gong, Yingxin; Wu, Bing; Zou, Lifang; Yi, Zhihua; Rao, Shenqiang; Li, Guilin; Zhang, Chunping; Jia, Tianyu; Zhao, Shanhong; Yuan, Huilong; Shi, Liran; Li, Lin; Liang, Shangdong; Liu, Shuangmei

2017-09-01

Neuropathic pain is a type of chronic pain caused by nervous system damage and dysfunction. The pathogenesis of chronic pain is complicated, and there are no effective therapies for neuropathic pain. Studies show that the P2X 4 receptor expressed in the satellite glial cells (SGCs) of dorsal root ganglia (DRG) is related to neuropathic pain. Artemisinin is a monomeric component extracted from traditional Chinese medicine and has a variety of important pharmacological effects and potential applications. This study observed the effect of artemisinin on neuropathic pain and delineated its possible mechanism. The chronic constriction injury (CCI) rat model was used in this study. The results demonstrated that artemisinin relieved pain behaviors in the CCI rats, inhibited the expression of P2X 4 receptor in the DRG, and decreased the ATP-activated currents in HEK293 cells transfected with P2X 4 plasmid. Dual-labeling immunofluorescence showed that the coexpression of P2X 4 receptor and glial fibrillary acidic protein (GFAP) in the DRG of CCI rats was increased compared to control rats. After CCI rats were treated with artemisinin, the coexpression of P2X 4 receptor and GFAP in the DRG was significantly decreased compared to the CCI group. This finding suggested that artemisinin could inhibit the nociceptive transmission mediated by P2X 4 receptor in the DRG SGCs and thus relieve pain behaviors in the CCI rats. Copyright © 2017 Elsevier Ltd. All rights reserved.

P2X₇ receptor of rat dorsal root ganglia is involved in the effect of moxibustion on visceral hyperalgesia.

PubMed

Liu, Shuangmei; Shi, Qingming; Zhu, Qicheng; Zou, Ting; Li, Guilin; Huang, An; Wu, Bing; Peng, Lichao; Song, Miaomiao; Wu, Qin; Xie, Qiuyu; Lin, Weijian; Xie, Wei; Wen, Shiyao; Zhang, Zhedong; Lv, Qiulan; Zou, Lifang; Zhang, Xi; Ying, Mofeng; Li, Guodong; Liang, Shangdong

2015-06-01

Irritable bowel syndrome (IBS) and inflammatory bowel disease often display visceral hypersensitivity. Visceral nociceptors after inflammatory stimulation generate afferent nerve impulses through dorsal root ganglia (DRG) transmitting to the central nervous system. ATP and its activated-purinergic 2X7 (P2X7) receptor play an important role in the transmission of nociceptive signal. Purinergic signaling is involved in the sensory transmission of visceral pain. Moxibustion is a therapy applying ignited mugwort directly or indirectly at acupuncture points or other specific parts of the body to treat diseases. Heat-sensitive acupoints are the corresponding points extremely sensitive to moxa heat in disease conditions. In this study, we aimed to investigate the relationship between the analgesic effect of moxibustion on a heat-sensitive acupoint "Dachangshu" and the expression levels of P2X7 receptor in rat DRG after chronic inflammatory stimulation of colorectal distension. Heat-sensitive moxibustion at Dachangshu acupoint inhibited the nociceptive signal transmission by decreasing the upregulated expression levels of P2X7 mRNA and protein in DRG induced by visceral pain, and reversed the abnormal expression of glial fibrillary acidic protein (GFAP, a marker of satellite glial cells) in DRG. Consequently, abdominal withdrawal reflex (AWR) score in a visceral pain model was reduced, and the pain threshold was elevated. Therefore, heat-sensitive moxibustion at Dachangshu acupoint can produce a therapeutic effect on IBS via inhibiting the nociceptive transmission mediated by upregulated P2X7 receptor.

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.

Sensory Symptom Profiles and Co-Morbidities in Painful Radiculopathy

PubMed Central

Gockel, Ulrich; Brosz, Mathias; Freynhagen, Rainer; Tölle, Thomas R.; Baron, Ralf

2011-01-01

Painful radiculopathies (RAD) and classical neuropathic pain syndromes (painful diabetic polyneuropathy, postherpetic neuralgia) show differences how the patients express their sensory perceptions. Furthermore, several clinical trials with neuropathic pain medications failed in painful radiculopathy. Epidemiological and clinical data of 2094 patients with painful radiculopathy were collected within a cross sectional survey (painDETECT) to describe demographic data and co-morbidities and to detect characteristic sensory abnormalities in patients with RAD and compare them with other neuropathic pain syndromes. Common co-morbidities in neuropathic pain (depression, sleep disturbance, anxiety) do not differ considerably between the three conditions. Compared to other neuropathic pain syndromes touch-evoked allodynia and thermal hyperalgesia are relatively uncommon in RAD. One distinct sensory symptom pattern (sensory profile), i.e., severe painful attacks and pressure induced pain in combination with mild spontaneous pain, mild mechanical allodynia and thermal hyperalgesia, was found to be characteristic for RAD. Despite similarities in sensory symptoms there are two important differences between RAD and other neuropathic pain disorders: (1) The paucity of mechanical allodynia and thermal hyperalgesia might be explained by the fact that the site of the nerve lesion in RAD is often located proximal to the dorsal root ganglion. (2) The distinct sensory profile found in RAD might be explained by compression-induced ectopic discharges from a dorsal root and not necessarily by nerve damage. These differences in pathogenesis might explain why medications effective in DPN and PHN failed to demonstrate efficacy in RAD. PMID:21573064

Perturbing NR2B-PSD-95 interaction relieves neuropathic pain by inactivating CaMKII-CREB signaling.

PubMed

Xu, Fangxia; Zhao, Xin; Liu, Lin; Song, Jia; Zhu, Yingjun; Chu, Shuaishuai; Shao, Xueming; Li, Xiuxiu; Ma, Zhengliang; Gu, Xiaoping

2017-09-06

Neuropathic pain is characterized by central sensitization. The interaction between N-methyl-D-aspartate receptors (NMDARs) and postsynaptic density protein-95 (PSD-95) plays a major role in central sensitization. Here, we aimed to investigate the analgesic effect of disruption of the interaction between NMDAR and PSD-95. Chronic dorsal root ganglia compression model rats were used to mimic sciatica. Thermal hyperalgesia and mechanical allodynia were evaluated. The expression of spinal phospho-NR2B, PSD-95, calcium/calmodulin-dependent protein kinase II (CaMKII), and cAMP response element binding protein (CREB) was measured using western blotting. A mimetic peptide Myr-NR2B9c was injected intrathecally to disrupt the interaction between PSD-95 and NR2B and detected by coimmunoprecipitation. Chronic dorsal root ganglia compression surgery induced thermal hyperalgesia and mechanical allodynia, and upregulated pain-related proteins such as phospho-NR2B, PSD-95, CaMKII, and CREB expressions in the spinal cord. Myr-NR2B9c disrupted the interaction between NR2B-containing NMDARs and PSD-95 in the spinal cord. Intrathecal administration of Myr-NR2B9c attenuated neuropathic pain behaviors and downregulated the expressions of phospho-NR2B, PSD-95, CaMKII, and CREB in the spinal cord. The present study indicates that dissociation of NR2B-containing NMDARs from PSD-95 inactivates CaMKII and CREB signaling and relieves pain.

An ensemble of regulatory elements controls Runx3 spatiotemporal expression in subsets of dorsal root ganglia proprioceptive neurons.

PubMed

Appel, Elena; Weissmann, Sarit; Salzberg, Yehuda; Orlovsky, Kira; Negreanu, Varda; Tsoory, Michael; Raanan, Calanit; Feldmesser, Ester; Bernstein, Yael; Wolstein, Orit; Levanon, Ditsa; Groner, Yoram

2016-12-01

The Runx3 transcription factor is essential for development and diversification of the dorsal root ganglia (DRGs) TrkC sensory neurons. In Runx3-deficient mice, developing TrkC neurons fail to extend central and peripheral afferents, leading to cell death and disruption of the stretch reflex circuit, resulting in severe limb ataxia. Despite its central role, the mechanisms underlying the spatiotemporal expression specificities of Runx3 in TrkC neurons were largely unknown. Here we first defined the genomic transcription unit encompassing regulatory elements (REs) that mediate the tissue-specific expression of Runx3. Using transgenic mice expressing BAC reporters spanning the Runx3 locus, we discovered three REs-dubbed R1, R2, and R3-that cross-talk with promoter-2 (P2) to drive TrkC neuron-specific Runx3 transcription. Deletion of single or multiple elements either in the BAC transgenics or by CRISPR/Cas9-mediated endogenous ablation established the REs' ability to promote and/or repress Runx3 expression in developing sensory neurons. Our analysis reveals that an intricate combinatorial interplay among the three REs governs Runx3 expression in distinct subtypes of TrkC neurons while concomitantly extinguishing its expression in non-TrkC neurons. These findings provide insights into the mechanism regulating cell type-specific expression and subtype diversification of TrkC neurons in developing DRGs. © 2016 Appel et al.; Published by Cold Spring Harbor Laboratory Press.

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.

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

Characteristics of dorsal root ganglia neurons sensitive to Substance P.

PubMed

Moraes, Eder Ricardo; Kushmerick, Christopher; Naves, Ligia Araujo

2014-11-27

Substance P modulates ion channels and the excitability of sensory neurons in pain pathways. Within the heterogeneous population of Dorsal Root Ganglia (DRG) primary sensory neurons, the properties of cells that are sensitive to Substance P are poorly characterized. To define this population better, dissociated rat DRG neurons were tested for their responsiveness to capsaicin, ATP and acid. Responses to ATP were classified according to the kinetics of current activation and desensitization. The same cells were then tested for modulation of action potential firing by Substance P. Acid and capsaicin currents were more frequently encountered in the largest diameter neurons. P2X3-like ATP currents were concentrated in small diameter neurons. Substance P modulated the excitability in 20 of 72 cells tested (28%). Of the Substance P sensitive cells, 10 exhibited an increase in excitability and 10 exhibited a decrease in excitability. There was no significant correlation between sensitivity to capsaicin and to Substance P. Excitatory effects of Substance P were strongly associated with cells that had large diameters, fired APs with large overshoots and slowly decaying after hyperpolarizations, and expressed acid currents at pH 7. No neurons that were excited by Substance P presented P2X3-like currents. In contrast, neurons that exhibited inhibitory effects of Substance P fired action potentials with rapidly decaying after hyperpolarizations. We conclude that excitatory effects of Substance P are restricted to a specific neuronal subpopulation with limited expression of putative nociceptive markers.

Neuro-fuzzy decoding of sensory information from ensembles of simultaneously recorded dorsal root ganglion neurons for functional electrical stimulation applications

NASA Astrophysics Data System (ADS)

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

2011-08-01

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

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

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.

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)

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.

Microbe-independent entry of oomycete RxLR effectors and fungal RxLR-like effectors into plant and animal cells is specific and reproducible.

PubMed

Tyler, Brett M; Kale, Shiv D; Wang, Qunqing; Tao, Kai; Clark, Helen R; Drews, Kelly; Antignani, Vincenzo; Rumore, Amanda; Hayes, Tristan; Plett, Jonathan M; Fudal, Isabelle; Gu, Biao; Chen, Qinghe; Affeldt, Katharyn J; Berthier, Erwin; Fischer, Gregory J; Dou, Daolong; Shan, Weixing; Keller, Nancy P; Martin, Francis; Rouxel, Thierry; Lawrence, Christopher B

2013-06-01

A wide diversity of pathogens and mutualists of plant and animal hosts, including oomycetes and fungi, produce effector proteins that enter the cytoplasm of host cells. A major question has been whether or not entry by these effectors can occur independently of the microbe or requires machinery provided by the microbe. Numerous publications have documented that oomycete RxLR effectors and fungal RxLR-like effectors can enter plant and animal cells independent of the microbe. A recent reexamination of whether the RxLR domain of oomycete RxLR effectors is sufficient for microbe-independent entry into host cells concluded that the RxLR domains of Phytophthora infestans Avr3a and of P. sojae Avr1b alone are NOT sufficient to enable microbe-independent entry of proteins into host and nonhost plant and animal cells. Here, we present new, more detailed data that unambiguously demonstrate that the RxLR domain of Avr1b does show efficient and specific entry into soybean root cells and also into wheat leaf cells, at levels well above background nonspecific entry. We also summarize host cell entry experiments with a wide diversity of oomycete and fungal effectors with RxLR or RxLR-like motifs that have been independently carried out by the seven different labs that coauthored this letter. Finally we discuss possible technical reasons why specific cell entry may have been not detected by Wawra et al. (2013).

The Early Entry of Al into Cells of Intact Soybean Roots (A Comparison of Three Developmental Root Regions Using Secondary Ion Mass Spectrometry Imaging).

PubMed Central

Lazof, D. B.; Goldsmith, J. G.; Rufty, T. W.; Linton, R. W.

1996-01-01

Al localization was compared in three developmental regions of primary root of an Al-sensitive soybean (Glycine max) genotype using secondary ion mass spectrometry. In cryosections obtained after a 4-h exposure to 38 [mu]M [Al3+], Al had penetrated across the root and into the stele in all three regions. Although the greatest localized Al concentration was consistently at the root periphery, the majority of the Al in each region had accumulated in cortical cells. It was apparent that the secondary ion mass spectrometry 27Al+ mass signal was spread throughout the intracellular area and was not particularly intense in the cell wall. Inclusion of some cell wall in determinations of the Al levels across the root radius necessitated that these serve as minimal estimates for intracellular Al. Total accumulation of intracellular Al for each region was 60, 73, and 210 nmol g-1 fresh weight after 4 h, increasing with root development. Early metabolic responses to external Al, including those that have been reported deep inside the root and in mature regions, might result directly from intracellular Al. These responses might include ion transport events at the endodermis of mature roots or events associated with lateral root emergence, as well as events within the root tip. PMID:12226447

Intractable Pruritus After Traumatic Spinal Cord Injury

PubMed Central

Crane, Deborah A; Jaffee, Kenneth M; Kundu, Anjana

2009-01-01

Background: This report describes a young woman with incomplete traumatic cervical spinal cord injury and intractable pruritus involving her dorsal forearm. Method: Case report. Findings: Anatomic distribution of the pruritus corresponded to the dermatomal distribution of her level of spinal cord injury and vertebral fusion. Symptoms were attributed to the spinal cord injury and possible cervical root injury. Pruritus was refractory to all treatments, including topical lidocaine, gabapentin, transcutaneous electrical nerve stimulation, intravenous Bier block, stellate ganglion block, and acupuncture. Conclusions: Further understanding of neuropathic pruritus is needed. Diagnostic workup of intractable pruritus should include advanced imaging to detect ongoing nerve root compression. If diagnostic studies suggest radiculopathy, epidural steroid injection should be considered. Because the autonomic nervous system may be involved in complex chronic pain or pruritic syndromes, sympatholysis via such techniques as stellate ganglion block might be effective. PMID:19777867

Prostatic acid phosphatase is an ectonucleotidase and suppresses pain by generating adenosine

PubMed Central

Zylka, Mark J.; Sowa, Nathaniel A.; Taylor-Blake, Bonnie; Twomey, Margaret A.; Herrala, Annakaisa; Voikar, Vootele; Vihko, Pirkko

2008-01-01

SUMMARY Thiamine monophosphatase (TMPase, also known as Fluoride-Resistant Acid Phosphatase) is a classic histochemical marker of small-diameter dorsal root ganglia neurons. The molecular identity of TMPase is currently unknown. We found that TMPase is identical to the transmembrane isoform of Prostatic Acid Phosphatase (PAP), an enzyme with unknown molecular and physiological functions. We then found that PAP knockout mice have normal acute pain sensitivity but enhanced sensitivity in chronic inflammatory and neuropathic pain models. In gain-of-function studies, intraspinal injection of PAP protein has potent anti-nociceptive, anti-hyperalgesic and anti-allodynic effects that last longer than the opioid analgesic morphine. PAP suppresses pain by functioning as an ecto-5’-nucleotidase. Specifically, PAP dephosphorylates extracellular adenosine monophosphate (AMP) to adenosine and activates A1-adenosine receptors in dorsal spinal cord. Our studies reveal molecular and physiological functions for PAP in purine nucleotide metabolism and nociception and suggest a novel use for PAP in the treatment of chronic pain. PMID:18940592

Theoretical performance and clinical evaluation of transverse tripolar spinal cord stimulation.

PubMed

Struijk, J J; Holsheimer, J; Spincemaille, G H; Gielen, F L; Hoekema, R

1998-09-01

A new type of spinal cord stimulation electrode, providing contact combinations with a transverse orientation, is presented. Electrodes were implanted in the cervical area (C4-C5) of two chronic pain patients and the stimulation results were subsequently simulated with a computer model consisting of a volume conductor model and active nerve fiber models. For various contact combinations a good match was obtained between the modeling results and the measurement data with respect to load resistance (less than 20% difference), perception thresholds (16% difference), asymmetry of paresthesia (significant correlation) and paresthesia distributions (weak correlation). The transversally oriented combinations provided the possibility to select either a preferential dorsal column stimulation, a preferential dorsal root stimulation or a mixed stimulation. The (a)symmetry of paresthesia could largely be affected in a predictable way by the selection of contact combinations as well. The transverse tripolar combination was shown to give a higher selectivity of paresthesia than monopolar and longitudinal dipolar combinations, at the cost of an increased current (more than twice).

Modified Posterior C1 Lateral Mass Screw Insertion for Type II Odontoid Process Fractures Using Intraoperative Computed Tomography-Based Spinal Navigation to Minimize Postoperative Occipital Neuralgia.

PubMed

Ishak, Basem; Schneider, Till; Tubbs, R Shane; Gimmy, Valerie; Younsi, Alexander; Unterberg, Andreas W; Kiening, Karl L

2017-11-01

Various surgical techniques have been described for treating odontoid instability and achieving effective stabilization. The earliest technique to be described proposed a C1 lateral mass entry point including neurectomy of the C2 nerve roots to ensure hemostasis. Because C2 neurectomy remains controversial, preservation of the C2 nerve root as described in Goel-Harms technique can lead to intractable occipital neuralgia and significant blood loss. The aim of this study was to modify the Goel-Harms technique with a high C1 lateral mass screw entry point to enhance overall intraoperative safety. Sixty-three patients (average age, 70 ± 16 years) with acute traumatic odontoid fracture type II underwent posterior stabilization with a modified posterior C1 lateral mass entry point using intraoperative computed tomography (CT)-guided spinal navigation. Complications were recorded, especially bleeding from the epidural venous plexus and development of occipital neuralgia. All patients were followed up for a minimum of 6 months. None of the patients developed occipital neuralgia or numbness. Blood transfusion was necessary in 1 patient because of a coagulation disorder. There was no bleeding from the epidural venous plexus. All screws were correctly placed. Two patients needed surgical revision (wound infection, dural tear). Two developed cardiopulmonary complications. Solid bony fusion was achieved in all patients. This study confirms that changing the C1 entry point to the junction of the posterior arch and superior-posterior part of the C1 lateral mass by using intraoperative CT navigation yields a safe and effective procedure with few complications. The overall complication rate was 6%. Copyright © 2017 Elsevier Inc. All rights reserved.

Root Systems of Individual Plants, and the Biotic and Abiotic Factors Controlling Their Depth and Distribution: a Synthesis Using a Global Database.

NASA Astrophysics Data System (ADS)

Tumber-Davila, S. J.; Schenk, H. J.; Jackson, R. B.

2017-12-01

This synthesis examines plant rooting distributions globally, by doubling the number of entries in the Root Systems of Individual Plants database (RSIP) created by Schenk and Jackson. Root systems influence many processes, including water and nutrient uptake and soil carbon storage. Root systems also mediate vegetation responses to changing climatic and environmental conditions. Therefore, a collective understanding of the importance of rooting systems to carbon sequestration, soil characteristics, hydrology, and climate, is needed. Current global models are limited by a poor understanding of the mechanisms affecting rooting, carbon stocks, and belowground biomass. This improved database contains an extensive bank of records describing the rooting system of individual plants, as well as detailed information on the climate and environment from which the observations are made. The expanded RSIP database will: 1) increase our understanding of rooting depths, lateral root spreads and above and belowground allometry; 2) improve the representation of plant rooting systems in Earth System Models; 3) enable studies of how climate change will alter and interact with plant species and functional groups in the future. We further focus on how plant rooting behavior responds to variations in climate and the environment, and create a model that can predict rooting behavior given a set of environmental conditions. Preliminary results suggest that high potential evapotranspiration and seasonality of precipitation are indicative of deeper rooting after accounting for plant growth form. When mapping predicted deep rooting by climate, we predict deepest rooting to occur in equatorial South America, Africa, and central India.

Nanomolar Oxytocin Synergizes with Weak Electrical Afferent Stimulation to Activate the Locomotor CPG of the Rat Spinal Cord In Vitro

PubMed Central

Dose, Francesco; Zanon, Patrizia; Coslovich, Tamara; Taccola, Giuliano

2014-01-01

Synergizing the effect of afferent fibre stimulation with pharmacological interventions is a desirable goal to trigger spinal locomotor activity, especially after injury. Thus, to better understand the mechanisms to optimize this process, we studied the role of the neuropeptide oxytocin (previously shown to stimulate locomotor networks) on network and motoneuron properties using the isolated neonatal rat spinal cord. On motoneurons oxytocin (1 nM–1 μM) generated sporadic bursts with superimposed firing and dose-dependent depolarization. No desensitization was observed despite repeated applications. Tetrodotoxin completely blocked the effects of oxytocin, demonstrating the network origin of the responses. Recording motoneuron pool activity from lumbar ventral roots showed oxytocin mediated depolarization with synchronous bursts, and depression of reflex responses in a stimulus and peptide-concentration dependent fashion. Disinhibited bursting caused by strychnine and bicuculline was accelerated by oxytocin whose action was blocked by the oxytocin antagonist atosiban. Fictive locomotion appeared when subthreshold concentrations of NMDA plus 5HT were coapplied with oxytocin, an effect prevented after 24 h incubation with the inhibitor of 5HT synthesis, PCPA. When fictive locomotion was fully manifested, oxytocin did not change periodicity, although cycle amplitude became smaller. A novel protocol of electrical stimulation based on noisy waveforms and applied to one dorsal root evoked stereotypic fictive locomotion. Whenever the stimulus intensity was subthreshold, low doses of oxytocin triggered fictive locomotion although oxytocin per se did not affect primary afferent depolarization evoked by dorsal root pulses. Among the several functional targets for the action of oxytocin at lumbar spinal cord level, the present results highlight how small concentrations of this peptide could bring spinal networks to threshold for fictive locomotion in combination with other protocols, and delineate the use of oxytocin to strengthen the efficiency of electrical stimulation to activate locomotor circuits. PMID:24658101

MrgC agonism at central terminals of primary sensory neurons inhibits neuropathic pain

PubMed Central

He, Shao-Qiu; Li, Zhe; Chu, Yu-Xia; Han, Liang; Xu, Qian; Li, Man; Yang, Fei; Liu, Qin; Tang, Zongxiang; Wang, Yun; Hin, Niyada; Tsukamoto, Takashi; Slusher, Barbara; Tiwari, Vinod; Shechter, Ronen; Wei, Feng; Raja, Srinivasa N; Dong, Xinzhong; Guan, Yun

2014-01-01

Chronic neuropathic pain is often refractory to current pharmacotherapies. The rodent Mas-related G-protein-coupled receptor subtype C (MrgC) shares substantial homogeneity with its human homolog, MrgX1, and is located specifically in small-diameter dorsal root ganglion (DRG) neurons. However, evidence regarding the role of MrgC in chronic pain conditions has been disparate and inconsistent. Accordingly, the therapeutic value of MrgX1 as a target for pain treatment in humans remains uncertain. Here, we found that intrathecal injection of BAM8-22 (a 15-amino acid peptide MrgC agonist) and JHU58 (a novel dipeptide MrgC agonist) inhibited both mechanical and heat hypersensitivity in rats after an L5 spinal nerve ligation (SNL). Intrathecal JHU58-induced pain inhibition was dose-dependent in SNL rats. Importantly, drug efficacy was lost in Mrg-cluster gene knockout (Mrg KO) mice and was blocked by gene silencing with intrathecal MrgC siRNA and by a selective MrgC receptor antagonist in SNL rats, suggesting that the drug action is MrgC-dependent. Further, in a mouse model of trigeminal neuropathic pain, microinjection of JHU58 into ipsilateral subnucleus caudalis inhibited mechanical hypersensitivity in wild-type but not Mrg KO mice. Finally, JHU58 attenuated the mEPSC frequency both in medullary dorsal horn neurons of mice after trigeminal nerve injury and in lumbar spinal dorsal horn of mice after SNL. We provide multiple lines of evidence that MrgC agonism at spinal but not peripheral sites may constitute a novel pain inhibitory mechanism that involves inhibition of peripheral excitatory inputs onto postsynaptic dorsal horn neurons in different rodent models of neuropathic pain. PMID:24333779

MiR-203 involves in neuropathic pain development and represses Rap1a expression in nerve growth factor differentiated neuronal PC12 cells.

PubMed

Li, Haixia; Huang, Yuguang; Ma, Chao; Yu, Xuerong; Zhang, Zhiyong; Shen, Le

2015-01-01

Although microRNAs (miRNAs) have been shown to play a role in numerous biological processes, their function in neuropathic pain is not clear. The rat bilateral sciatic nerve chronic constriction injury (bCCI) is an established model of neuropathic pain, so we examined miRNA expression and function in the spinal dorsal horn in bCCI rats. Microarray and real-time polymerase chain reaction were used to examine the expression of miRNA in nerve system of bCCI rats, and the targets of miRNA were predicted by bioinformatic approaches. The function of specific miRNA was estimated through the methods of gene engineering. This study revealed substantially (∼10-fold) decreased miR-203 expression in the spinal dorsal horns but not the dorsal root ganglions, hippocampus, or anterior cingulate cortexes of bCCI rats. Rap1a protein expression was upregulated in bCCI rat spinal dorsal horns. We further verified that miR-203 directly targeted the 3'-untranslated region of the rap1a gene, thereby decreasing rap1a protein expression in neuron-like cells. Rap1a has diverse neuronal functions and their perturbation is responsible for several mental disorders. For example, Rap1a/MEK/ERK is involved in peripheral sensitization. These data suggest a potential role for miR-203 in regulating neuropathic pain development, and Rap1a is a validated target gene in vitro. Results from our study and others indicate the possibility that Rap1a may be involved in pain. We hope that these results can provide support for future research into miR-203 in gene therapy for neuropathic pain.

The distribution of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) in the medulla oblongata, spinal cord, cranial and spinal nerves of frog, Microhyla ornata.

PubMed

Jadhao, Arun G; Biswas, Saikat P; Bhoyar, Rahul C; Pinelli, Claudia

2017-04-01

Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) enzymatic activity has been reported in few amphibian species. In this study, we report its unusual localization in the medulla oblongata, spinal cord, cranial nerves, spinal nerves, and ganglions of the frog, Microhyla ornata. In the rhombencephalon, at the level of facial and vagus nerves, the NADPH-d labeling was noted in the nucleus of the abducent and facial nerves, dorsal nucleus of the vestibulocochlear nerve, the nucleus of hypoglossus nerve, dorsal and lateral column nucleus, the nucleus of the solitary tract, the dorsal field of spinal grey, the lateral and medial motor fields of spinal grey and radix ventralis and dorsalis (2-10). Many ependymal cells around the lining of the fourth ventricle, both facial and vagus nerves and dorsal root ganglion, were intensely labeled with NADPH-d. Most strikingly the NADPH-d activity was seen in small and large sized motoneurons in both medial and lateral motor neuron columns on the right and left sides of the brain. This is the largest stained group observed from the caudal rhombencephalon up to the level of radix dorsalis 10 in the spinal cord. The neurons were either oval or elongated in shape with long processes and showed significant variation in the nuclear and cellular diameter. A massive NADPH-d activity in the medulla oblongata, spinal cord, and spinal nerves implied an important role of this enzyme in the neuronal signaling as well as in the modulation of motor functions in the peripheral nervous systems of the amphibians. Copyright © 2017 Elsevier B.V. All rights reserved.

Dense transient receptor potential cation channel, vanilloid family, type 2 (TRPV2) immunoreactivity defines a subset of motoneurons in the dorsal lateral nucleus of the spinal cord, the nucleus ambiguus and the trigeminal motor nucleus in rat.

PubMed

Lewinter, R D; Scherrer, G; Basbaum, A I

2008-01-02

The transient receptor potential cation channel, vanilloid family, type 2 (TRPV2) is a member of the TRPV family of proteins and is a homologue of the capsaicin/vanilloid receptor (transient receptor potential cation channel, vanilloid family, type 1, TRPV1). Like TRPV1, TRPV2 is expressed in a subset of dorsal root ganglia (DRG) neurons that project to superficial laminae of the spinal cord dorsal horn. Because noxious heat (>52 degrees C) activates TRPV2 in transfected cells this channel has been implicated in the processing of high intensity thermal pain messages in vivo. In contrast to TRPV1, however, which is restricted to small diameter DRG neurons, there is significant TRPV2 immunoreactivity in a variety of CNS regions. The present report focuses on a subset of neurons in the brainstem and spinal cord of the rat including the dorsal lateral nucleus (DLN) of the spinal cord, the nucleus ambiguus, and the motor trigeminal nucleus. Double label immunocytochemistry with markers of motoneurons, combined with retrograde labeling, established that these cells are, in fact, motoneurons. With the exception of their smaller diameter, these cells did not differ from other motoneurons, which are only lightly TRPV2-immunoreactive. As for the majority of DLN neurons, the densely-labeled populations co-express androgen receptor and follow normal DLN ontogeny. The functional significance of the very intense TRPV2 expression in these three distinct spinal cord and brainstem motoneurons groups remains to be determined.

Neto2 Assembles with Kainate Receptors in DRG Neurons during Development and Modulates Neurite Outgrowth in Adult Sensory Neurons.

PubMed

Vernon, Claire G; Swanson, Geoffrey T

2017-03-22

Peripheral sensory neurons in the dorsal root ganglia (DRG) are the initial transducers of sensory stimuli, including painful stimuli, from the periphery to central sensory and pain-processing centers. Small- to medium-diameter non-peptidergic neurons in the neonatal DRG express functional kainate receptors (KARs), one of three subfamilies of ionotropic glutamate receptors, as well as the putative KAR auxiliary subunit Neuropilin- and tolloid-like 2 (Neto2). Neto2 alters recombinant KAR function markedly but has yet to be confirmed as an auxiliary subunit that assembles with and alters the function of endogenous KARs. KARs in neonatal DRG require the GluK1 subunit as a necessary constituent, but it is unclear to what extent other KAR subunits contribute to the function and proposed roles of KARs in sensory ganglia, which include promotion of neurite outgrowth and modulation of glutamate release at the DRG-dorsal horn synapse. In addition, KARs containing the GluK1 subunit are implicated in modes of persistent but not acute pain signaling. We show here that the Neto2 protein is highly expressed in neonatal DRG and modifies KAR gating in DRG neurons in a developmentally regulated fashion in mice. Although normally at very low levels in adult DRG neurons, Neto2 protein expression can be upregulated via MEK/ERK signaling and after sciatic nerve crush and Neto2 -/- neurons from adult mice have stunted neurite outgrowth. These data confirm that Neto2 is a bona fide KAR auxiliary subunit that is an important constituent of KARs early in sensory neuron development and suggest that Neto2 assembly is critical to KAR modulation of DRG neuron process outgrowth. SIGNIFICANCE STATEMENT Pain-transducing peripheral sensory neurons of the dorsal root ganglia (DRG) express kainate receptors (KARs), a subfamily of glutamate receptors that modulate neurite outgrowth and regulate glutamate release at the DRG-dorsal horn synapse. The putative KAR auxiliary subunit Neuropilin- and tolloid-like 2 (Neto2) is also expressed in DRG. We show here that it is a developmentally downregulated but dynamic component of KARs in these neurons, that it contributes to regulated neurite regrowth in adult neurons, and that it is increased in adult mice after nerve injury. Our data confirm Neto2 as a KAR auxiliary subunit and expand our knowledge of the molecular composition of KARs in nociceptive neurons, a key piece in understanding the mechanistic contribution of KAR signaling to pain-processing circuits. Copyright © 2017 the authors 0270-6474/17/373352-12$15.00/0.

Neto2 Assembles with Kainate Receptors in DRG Neurons during Development and Modulates Neurite Outgrowth in Adult Sensory Neurons

PubMed Central

Vernon, Claire G.

2017-01-01

Peripheral sensory neurons in the dorsal root ganglia (DRG) are the initial transducers of sensory stimuli, including painful stimuli, from the periphery to central sensory and pain-processing centers. Small- to medium-diameter non-peptidergic neurons in the neonatal DRG express functional kainate receptors (KARs), one of three subfamilies of ionotropic glutamate receptors, as well as the putative KAR auxiliary subunit Neuropilin- and tolloid-like 2 (Neto2). Neto2 alters recombinant KAR function markedly but has yet to be confirmed as an auxiliary subunit that assembles with and alters the function of endogenous KARs. KARs in neonatal DRG require the GluK1 subunit as a necessary constituent, but it is unclear to what extent other KAR subunits contribute to the function and proposed roles of KARs in sensory ganglia, which include promotion of neurite outgrowth and modulation of glutamate release at the DRG–dorsal horn synapse. In addition, KARs containing the GluK1 subunit are implicated in modes of persistent but not acute pain signaling. We show here that the Neto2 protein is highly expressed in neonatal DRG and modifies KAR gating in DRG neurons in a developmentally regulated fashion in mice. Although normally at very low levels in adult DRG neurons, Neto2 protein expression can be upregulated via MEK/ERK signaling and after sciatic nerve crush and Neto2−/− neurons from adult mice have stunted neurite outgrowth. These data confirm that Neto2 is a bona fide KAR auxiliary subunit that is an important constituent of KARs early in sensory neuron development and suggest that Neto2 assembly is critical to KAR modulation of DRG neuron process outgrowth. SIGNIFICANCE STATEMENT Pain-transducing peripheral sensory neurons of the dorsal root ganglia (DRG) express kainate receptors (KARs), a subfamily of glutamate receptors that modulate neurite outgrowth and regulate glutamate release at the DRG–dorsal horn synapse. The putative KAR auxiliary subunit Neuropilin- and tolloid-like 2 (Neto2) is also expressed in DRG. We show here that it is a developmentally downregulated but dynamic component of KARs in these neurons, that it contributes to regulated neurite regrowth in adult neurons, and that it is increased in adult mice after nerve injury. Our data confirm Neto2 as a KAR auxiliary subunit and expand our knowledge of the molecular composition of KARs in nociceptive neurons, a key piece in understanding the mechanistic contribution of KAR signaling to pain-processing circuits. PMID:28235897

A Novel Approach for Effectively Treating SCI Pain, Improving Opioid Efficacy, and Preventing Opioid-Induced Constipation: Key Role of Toll-Like Receptor 4 (TLR4)

DTIC Science & Technology

2014-10-01

RESPONSIBLE PERSON USAMRMC a. REPORT U b. ABSTRACT U c. THIS PAGE U UU 17 19b. TELEPHONE NUMBER (include area code ) 2 Table of Contents...after dorsal root avulsion, during the acute stages of injury? 3b. SNAP surgery and testing (Hargreaves, motor function and constipation tests during the...first week post- surgery with co-administration of morphine and (+)-naltrexone (vs. vehicles) starting 1 or 24 hr post surgery ; von Frey and motor

Clinical response to dorsal duct drainage via the minor papilla in refractory obstructing chronic calcific pancreatitis

PubMed Central

Kwon, Chang-Il; Gromski, Mark A.; Sherman, Stuart; El Hajj, Ihab I.; Easler, Jeffrey J.; Watkins, James; McHenry, Lee; Lehman, Glen A.; Fogel, Evan L.

2017-01-01

Background and study aims Complete stone removal from the main pancreatic duct might not be achieved in all patients with obstructive chronic calcific pancreatitis. We report our results for endoscopic dorsal pancreatic duct (DPD) bypass of obstructing stones in the ventral pancreatic duct (VPD). Patients and methods 16 patients with obstructive chronic calcific pancreatitis were treated with a DPD bypass. Clinical success was defined as significant pain relief and no hospital admissions for pain management during the ongoing treatment period. Results Among 16 patients meeting entry criteria, 10 (62.5%) had a history of unsuccessful endoscopic therapy, and 8 had failed extracorporeal shockwave lithotripsy (ESWL). Clinical success was achieved in 12 patients (75 %). Among these responders, 10 patients (83.3 %) had markedly improved or complete pain relief after the first stent placement, which persisted throughout the follow-up period; 11 patients (91.7 %) were able to discontinue their daily analgesics. Conclusions In selected patients with obstructive chronic calcific pancreatitis, the DPD bypass may be considered as a rescue endoscopic therapy, potentially obviating the need for surgery when standard endoscopic methods and ESWL fail. PMID:28201840

Dorsal hippocampal opioidergic system modulates anxiety-like behaviors in adult male Wistar rats.

PubMed

Solati, Jalal; Zarrindast, Mohammad-Reza; Salari, Ali-Akbar

2010-12-01

In the present study, we investigated the possible influence of the opioidergic system of the dorsal hippocampus on anxiety-like behaviors. Elevated plus-maze, which is one of the methods used for testing anxiety, was used in the present study. Rats were anesthetized with ketamine and xylazine and special cannulas were inserted stereotaxically into the CA1 region of the dorsal hippocampus. After 1 week of recovery, the effects of intra-CA1 administration of morphine (0.25, 0.5, 1 and 2 µg/rat; 1 µl/rat; 0.5 µl/in each side), naloxone (2, 4, 6 and 8 µg/rat), enkephalin (1, 2, 5 and 10 µg/rat) and naltrindole (0.25, 0.5, 1 and 2 µg/rat) on percentage open arm time (%OAT) and percentage open arm entries (%OAE) were determined. Bilateral administration of morphine into CA1 decreases %OAT and %OAE, indicating an anxiogenic-like effect. Intra-CA1 injection of naloxone, an opioid receptor antagonist, increased both %OAT and %OAE, parameters of anxiolytic-like behavior. Bilateral administration of δ-opioid receptor agonist, [D-Pen(2,5) ]-enkephalin acetate hydrate into the CA1, induced an anxiolytic-like effect. Furthermore, intra-CA1 injection of δ-opioid receptor antagonist, naltrindole hydrochloride, increased anxiety-related behaviors. The results of the present study demonstrate that activation of μ-opioid receptors in this area produce an anxiogenic response while activation of δ-opioid receptors produces an anxiolytic response. © 2010 The Authors. Psychiatry and Clinical Neurosciences © 2010 Japanese Society of Psychiatry and Neurology.

The Toll-Dorsal Pathway Is Required for Resistance to Viral Oral Infection in Drosophila

PubMed Central

Ferreira, Álvaro Gil; Naylor, Huw; Esteves, Sara Santana; Pais, Inês Silva; Martins, Nelson Eduardo; Teixeira, Luis

2014-01-01

Pathogen entry route can have a strong impact on the result of microbial infections in different hosts, including insects. Drosophila melanogaster has been a successful model system to study the immune response to systemic viral infection. Here we investigate the role of the Toll pathway in resistance to oral viral infection in D. melanogaster. We show that several Toll pathway components, including Spätzle, Toll, Pelle and the NF-kB-like transcription factor Dorsal, are required to resist oral infection with Drosophila C virus. Furthermore, in the fat body Dorsal is translocated from the cytoplasm to the nucleus and a Toll pathway target gene reporter is upregulated in response to Drosophila C Virus infection. This pathway also mediates resistance to several other RNA viruses (Cricket paralysis virus, Flock House virus, and Nora virus). Compared with control, viral titres are highly increased in Toll pathway mutants. The role of the Toll pathway in resistance to viruses in D. melanogaster is restricted to oral infection since we do not observe a phenotype associated with systemic infection. We also show that Wolbachia and other Drosophila-associated microbiota do not interact with the Toll pathway-mediated resistance to oral infection. We therefore identify the Toll pathway as a new general inducible pathway that mediates strong resistance to viruses with a route-specific role. These results contribute to a better understanding of viral oral infection resistance in insects, which is particularly relevant in the context of transmission of arboviruses by insect vectors. PMID:25473839

Oral Application of Magnesium-L-Threonate Attenuates Vincristine-induced Allodynia and Hyperalgesia by Normalization of Tumor Necrosis Factor-α/Nuclear Factor-κB Signaling.

PubMed

Xu, Ting; Li, Dai; Zhou, Xin; Ouyang, Han-Dong; Zhou, Li-Jun; Zhou, Hang; Zhang, Hong-Mei; Wei, Xu-Hong; Liu, Guosong; Liu, Xian-Guo

2017-06-01

Antineoplastic agents, including vincristine, often induce neuropathic pain and magnesium deficiency clinically, but the causal link between them has not been determined. No drug is available for treating this form of neuropathic pain. Injection of vincristine (0.1 mg · kg · day, intraperitoneally, for 10 days) was used to induce nociceptive sensitization, which was accessed with von Frey hairs and the plantar tester in adult male Sprague-Dawley rats. Magnesium-L- threonate was administered through drinking water (604 mg · kg · day). Extracellular and intracellular free Mg were measured by Calmagite chromometry and flow cytometry. Molecular biologic and electrophysiologic experiments were performed to expose the underlying mechanisms. Vincristine injection induced allodynia and hyperalgesia (n = 12), activated tumor necrosis factor-α/nuclear factor-κB signaling, and reduced free Mg in cerebrospinal fluid by 21.7 ± 6.3% (mean ± SD; n = 13) and in dorsal root ganglion neurons by 27 ± 6% (n = 11). Reducing Mg activated tumor necrosis factor-α/nuclear factor-κB signaling in cultured dorsal root ganglion neurons. Oral application of magnesium-L-threonate prevented magnesium deficiency and attenuated both activation of tumor necrosis factor-α/nuclear factor-κB signaling and nociceptive sensitization (n = 12). Mechanistically, vincristine induced long-term potentiation at C-fiber synapses, up-regulated N-methyl-D-aspartate receptor type 2B subunit of N-methyl-D-aspartate receptor, and led to peptidergic C-fiber sprouting in spinal dorsal horn (n = 6 each). The vincristine-induced pathologic plasticity was blocked by intrathecal injection of nuclear factor-κB inhibitor (n = 6), mimicked by tumor necrosis factor-α, and substantially prevented by oral magnesium-L-threonate (n = 5). Vincristine may activate tumor necrosis factor-α/nuclear factor-κB pathway by reduction of intracellular magnesium, leading to spinal pathologic plasticity and nociceptive sensitization. Oral magnesium-L-threonate that prevents the magnesium deficiency is a novel approach to prevent neuropathic pain induced by chemotherapy.

Phenotypic plasticity in haptoral structures of Ligophorus cephali (Monogenea: Dactylogyridae) on the flathead mullet (Mugil cephalus): a geometric morphometric approach.

PubMed

Rodríguez-González, Abril; Míguez-Lozano, Raúl; Llopis-Belenguer, Cristina; Balbuena, Juan Antonio

2015-04-01

Evaluating phenotypic plasticity in attachment organs of parasites can provide information on the capacity to colonise new hosts and illuminate evolutionary processes driving host specificity. We analysed the variability in shape and size of the dorsal and ventral anchors of Ligophorus cephali from Mugil cephalus by means of geometric morphometrics and multivariate statistics. We also assessed the morphological integration between anchors and between the roots and points in order to gain insight into their functional morphology. Dorsal and ventral anchors showed a similar gradient of overall shape variation, but the amount of localised changes was much higher in the former. Statistical models describing variations in shape and size revealed clear differences between anchors. The dorsal anchor/bar complex seems more mobile than the ventral one in Ligophorus, and these differences may reflect different functional roles in attachment to the gills. The lower residual variation associated with the ventral anchor models suggests a tighter control of their shape and size, perhaps because these anchors seem to be responsible for firmer attachment and their size and shape would allow more effective responses to characteristics of the microenvironment within the individual host. Despite these putative functional differences, the high level of morphological integration indicates a concerted action between anchors. In addition, we found a slight, although significant, morphological integration between roots and points in both anchors, which suggests that a large fraction of the observed phenotypic variation does not compromise the functional role of anchors as levers. Given the low level of genetic variation in our sample, it is likely that much of the morphological variation reflects host-driven plastic responses. This supports the hypothesis of monogenean specificity through host-switching and rapid speciation. The present study demonstrates the potential of geometric morphometrics to provide new and previously unexplored insights into the functional morphology of attachment and evolutionary processes of host-parasite coevolution. Copyright © 2015 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

Characterization of Macrophage/Microglial Activation and Effect of Photobiomodulation in the Spared Nerve Injury Model of Neuropathic Pain.

PubMed

Kobiela Ketz, Ann; Byrnes, Kimberly R; Grunberg, Neil E; Kasper, Christine E; Osborne, Lisa; Pryor, Brian; Tosini, Nicholas L; Wu, Xingjia; Anders, Juanita J

2017-05-01

Neuropathic pain is common and debilitating with limited effective treatments. Macrophage/microglial activation along ascending somatosensory pathways following peripheral nerve injury facilitates neuropathic pain. However, polarization of macrophages/microglia in neuropathic pain is not well understood. Photobiomodulation treatment has been used to decrease neuropathic pain, has anti-inflammatory effects in spinal injury and wound healing models, and modulates microglial polarization in vitro. Our aim was to characterize macrophage/microglia response after peripheral nerve injury and modulate the response with photobiomodulation. Adult male Sprague-Dawley rats were randomly assigned to sham (N = 13), spared nerve injury (N = 13), or injury + photobiomodulation treatment groups (N = 7). Mechanical hypersensitivity was assessed with electronic von Frey. Photobiomodulation (980 nm) was applied to affected hind paw (output power 1 W, 20 s, 41cm above skin, power density 43.25 mW/cm 2 , dose 20 J), dorsal root ganglia (output power 4.5W, 19s, in skin contact, power density 43.25 mW/cm 2 , dose 85.5 J), and spinal cord regions (output power 1.5 W, 19s, in skin contact, power density 43.25 mW/cm 2 , dose 28.5 J) every other day from day 7-30 post-operatively. Immunohistochemistry characterized macrophage/microglial activation. Injured groups demonstrated mechanical hypersensitivity 1-30 days post-operatively. Photobiomodulation-treated animals began to recover after two treatments; at day 26, mechanical sensitivity reached baseline. Peripheral nerve injury caused region-specific macrophages/microglia activation along spinothalamic and dorsal-column medial lemniscus pathways. A pro-inflammatory microglial marker was expressed in the spinal cord of injured rats compared to photobiomodulation-treated and sham group. Photobiomodulation-treated dorsal root ganglion macrophages expressed anti-inflammatory markers. Photobiomodulation effectively reduced mechanical hypersensitivity, potentially through modulating macrophage/microglial activation to an anti-inflammatory phenotype. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. 2016. This work is written by US Government employees and is in the public domain in the US.

Hereditary sensory ataxic neuropathy associated with proximal muscle weakness in the lower extremities.

PubMed

Murakami, Tatsufumi; Fukai, Yuta; Rikimaru, Mitsue; Henmi, Shoji; Ohsawa, Yutaka; Sunada, Yoshihide

2010-04-15

We describe three patients from the same family with hereditary sensory ataxic neuropathy followed by proximal muscle weakness in the lower extremities. Sensory ataxic gait began as an initial symptom when patients were in their 50s. Mild proximal weakness in the lower extremities appeared several years later. Serum creatine kinase was mildly elevated. Nerve conduction studies revealed sensory dominant axonal neuropathy, and short sensory evoked potentials showed involvement of the sensory nerve axon, dorsal root ganglia and posterior funiculus of the spinal cord. Needle electromyography showed fibrillation, positive sharp waves, and multiple giant motor unit potentials, suggesting the involvement of anterior horn motor neurons or the anterior root. Autosomal recessive inheritance was considered, because of consanguinity. The disorder described here may be a new clinical entity with unique clinical manifestations. Copyright 2009 Elsevier B.V. All rights reserved.

Identifying motor and sensory myelinated axons in rabbit peripheral nerves by histochemical staining for carbonic anhydrase and cholinesterase activities

NASA Technical Reports Server (NTRS)

Riley, Danny A.; Sanger, James R.; Matloub, Hani S.; Yousif, N. John; Bain, James L. W.

1988-01-01

Carbonic anhydrase (CA) and cholinesterase (CE) histochemical staining of rabbit spinal nerve roots and dorsal root ganglia demonstrated that among the reactive myeliated axons, with minor exceptions, sensory axons were CA positive and CE negative whereas motor axons were CA negative and CE positive. The high specificity was achieved by adjusting reaction conditions to stain subpopulations of myelinated axons selectively while leaving 50 percent or so unstained. Fixation with glutaraldehyde appeared necessary for achieving selectivity. Following sciatic nerve transection, the reciprocal staining pattern persisted in damaged axons and their regenerating processes which formed neuromas within the proximal nerve stump. Within the neuromas, CA-stained sensory processes were elaborated earlier and in greater numbers than CE-stained regenerating motor processes. The present results indicate that histochemical axon typing can be exploited to reveal heterogeneous responses of motor and sensory axons to injury.

Tachykinin actions on deep dorsal horn neurons in vitro: an electrophysiological and morphological study in the immature rat.

PubMed

King, A E; Slack, J R; Lopez-Garcia, J A; Ackley, M A

1997-05-01

To assess whether functional neurokinin receptors exist in the deep dorsal horn of the rat, the actions of the selective neurokinin-1 receptor (NK1R) agonist [Sar9,Met(O2)11]substance P ([Sar9,Met(O2)11]SP), the neurokinin-2 receptor (NK2R) agonists [beta-Ala8]NKA(4-10) and GR64349 and the neurokinin-3 receptor (NK3R) agonist senktide were examined intracellularly in vitro. [Sar9,Met(O2)11]SP (1-4 microM) and senktide (1-2 microM) elicited slow depolarizations (<10 mV) associated with increased synaptic activity and cell firing. [beta-Ala8]NKA(4-10) (10-20 microM) and GR64349 (0.25-10 microM) caused small depolarizations (<2.0 mV) and no firing. Neurons were categorized as either 'tonic' or 'phasic' depending on their firing response to direct current step depolarizations. Tonic neurons, which, unlike phasic neurons, display no spike firing accommodation, generated a significantly larger depolarization to the NK1R and NK3R agonists. The putative contribution of these receptors to primary afferent-mediated synaptic transmission was assessed by testing the NK1R antagonist GR82334 (1 microM), the NK2R antagonist MEN10,376 (1 microM) and the NK3R antagonist [Trp7,beta-Ala8]NKA(4-10) (1 microM) against the dorsal root-evoked excitatory postsynaptic potential (DR-EPSP). GR82334 and [Trp7,beta-Ala8]NKA(4-10) significantly reduced (P < or = 0.05) the duration but not the amplitude of the DR-EPSP. MEN10,376 (1 microM) had no effect on DR-EPSP amplitude or duration. Morphological detail was obtained for seven biocytin-filled deep dorsal horn neurons tested with [Sar9,Met(O2)11]SP. Five neurons responded to the NK1R agonist, and two of these had dorsally directed dendrites into the substantia gelatinosa. The other three [Sar9,Met(O2)11]SP-sensitive neurons had dendrites within deeper laminae. These data support the existence of functional NK1Rs and NK3Rs in the deep dorsal horn which may be involved in mediating sensory afferent inputs from nociceptors.

Implant-derived magnesium induces local neuronal production of CGRP to improve bone-fracture healing in rats

PubMed Central

Zhang, Yifeng; Xu, Jiankun; Ruan, Ye Chun; Yu, Mei Kuen; O’Laughlin, Micheal; Wise, Helen; Chen, Di; Tian, Li; Shi, Dufang; Wang, Jiali; Chen, Sihui; Feng, Jian Q; Chow, Dick Ho Kiu; Xie, Xinhui; Zheng, Lizhen; Huang, Le; Huang, Shuo; Leung, Kwoksui; Lu, Na; Zhao, Lan; Li, Huafang; Zhao, Dewei; Guo, Xia; Chan, Kaiming; Witte, Frank; Chan, Hsiao Chang; Zheng, Yufeng; Qin, Ling

2017-01-01

Orthopedic implants containing biodegradable magnesium have been used for fracture repair with considerable efficacy; however, the underlying mechanisms by which these implants improve fracture healing remain elusive. Here we show the formation of abundant new bone at peripheral cortical sites after intramedullary implantation of a pin containing ultrapure magnesium into the intact distal femur in rats. This response was accompanied by substantial increases of neuronal calcitonin gene-related polypeptide-α (CGRP) in both the peripheral cortex of the femur and the ipsilateral dorsal root ganglia (DRG). Surgical removal of the periosteum, capsaicin denervation of sensory nerves or knockdown in vivo of the CGRP-receptor-encoding genes Calcrl or Ramp1 substantially reversed the magnesium-induced osteogenesis that we observed in this model. Overexpression of these genes, however, enhanced magnesium-induced osteogenesis. We further found that an elevation of extracellular magnesium induces magnesium transporter 1 (MAGT1)-dependent and transient receptor potential cation channel, subfamily M, member 7 (TRPM7)-dependent magnesium entry, as well as an increase in intracellular adenosine triphosphate (ATP) and the accumulation of terminal synaptic vesicles in isolated rat DRG neurons. In isolated rat periosteum-derived stem cells, CGRP induces CALCRL-and RAMP1-dependent activation of cAMP-responsive element binding protein 1 (CREB1) and SP7 (also known as osterix), and thus enhances osteogenic differentiation of these stem cells. Furthermore, we have developed an innovative, magnesium-containing intramedullary nail that facilitates femur fracture repair in rats with ovariectomy-induced osteoporosis. Taken together, these findings reveal a previously undefined role of magnesium in promoting CGRP-mediated osteogenic differentiation, which suggests the therapeutic potential of this ion in orthopedics. PMID:27571347

NT-3 promotes proprioceptive axon regeneration when combined with activation of the mTor intrinsic growth pathway but not with reduction of myelin extrinsic inhibitors

PubMed Central

Liu, Yingpeng; Kelamangalath, Lakshmi; Kim, Hyukmin; Han, Seung Baek; Tang, Xiaoqing; Zhai, Jinbin; Hong, Jee W; Lin, Shen; Son, Young-Jin; Smith, George M.

2016-01-01

Although previous studies have identified several strategies to stimulate regeneration of CNS axons, extensive regeneration and functional recovery have remained a major challenge, particularly for large diameter myelinated axons. Within the CNS, myelin is thought to inhibit axon regeneration, while modulating activity of the mTOR pathway promotes regeneration of injured axons. In this study, we examined NT-3 mediated regeneration of sensory axons through the dorsal root entry zone in a triple knockout of myelin inhibitory proteins or after activation of mTOR using a constitutively active (ca) Rheb in DRG neurons to determine the influence of environmental inhibitory or activation of intrinsic growth pathways could enhance NT-3-mediate regeneration. Loss of myelin inhibitory proteins showed modest enhancement of sensory axon regeneration. In mTOR studies, we found a dramatic age related decrease in the mTOR activation as determined by phosphorylation of the downstream marker S6 ribosomal subunit. Expression of caRheb within adult DRG neurons in vitro increased S6 phosphorylation and doubled the overall length of neurite outgrowth, which was reversed in the presence of rapamycin. In adult female rats, combined expression of caRheb in DRG neurons and NT-3 within the spinal cord increased regeneration of sensory axons almost 3 fold when compared to NT-3 alone. Proprioceptive assessment using a grid runway indicates functionally significant regeneration of large-diameter myelinated sensory afferents. Our results indicate that caRheb-induced increase in mTOR activation enhances neurotrophin-3 induced regeneration of large-diameter myelinated axons. PMID:27264357

SU-E-T-669: Radiosurgery Failure for Trigeminal Neuralgia: A Study of Radiographic Spatial Fidelity

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

Howe, J; Spalding, A

Purpose: Management of Trigeminal Neuralgia with radiosurgery is well established, but often met with limited success. Recent advancements in imaging afford improvements in target localization for radiosurgery. Methods: A Trigeminal Neuralgia radiosurgery specific protocol was established for MR enhancement of the trigeminal nerve using a CISS scan with slice spacing of 0.7mm. Computed Tomography simulation was performed using axial slices on a 40 slice CT with slice spacing of 0.6mm. These datasets were registered using a mutual information algorithm and localized in a stereotactic coordinate system. Image registration between the MR and CT was evaluated for each patient by amore » Medical Physicist to ensure accuracy. The dorsal root entry zone target was defined on the CISS MR by a Neurosurgeon and dose calculations performed on the localized CT. Treatment plans were reviewed and approved by a Radiation Oncologist and Neurosurgeon. Image guided radiosurgery was delivered using positioning tolerance of 0.5mm and 1°. Eight patients with Trigeminal Neuralgia were treated with this protocol. Results: Seven patients reported a favorable response to treatment with average Barrow Neurological Index pain score of four before treatment and one following treatment. Only one patient had a BNI>1 following treatment and review of the treatment plan revealed that the CISS MR was registered to the CT via a low resolution (5mm slice spacing) T2 MR. All other patients had CISS MR registered directly with the localized CT. This patient was retreated 6 months later using direct registration between CISS MR and localized CT and subsequently responded to treatment with a BNI of one. Conclusion: Frameless radiosurgery offers an effective solution to Trigeminal Neuralgia management provided appropriate technology and imaging protocols (utilizing submillimeter imaging) are established and maintained.« less

The pentose cycle (hexose monophosphate shunt). Rigorous evaluation of limits to the flux from glucose using 14CO2 data, with applications to peripheral ganglia of chicken embryos.

PubMed

Larrabee, M G

1989-09-25

The difference between the 14CO2 outputs from [1-14C]glucose and [6-14C]glucose has frequently been used as a measure of activity in the hexose monophosphate shunt without considering the exact significance of this difference. Assuming only 1) that all C-1 of glucose is released to CO2 on entry to the shunt and 2) that the shunt provides the only mechanism for increasing C-1 of glucose over C-6 of glucose in CO2, it is very simply shown that the flux from glucose to the shunt is not less than the difference between the 14CO2 outputs at any time after adding labeled glucose nor more than the steady-state output of 14CO2 from [1-14C]glucose. Moreover, absence of a 14CO2 difference does not prove that the shunt is absent or inactive. The value for the minimum flux rate can be maximized by following the time course of the C-1 - C-6 difference in 14CO2 during the transient phase before isotopic equilibration is complete, but useful values can be obtained when the time course is not available. The above relationships are applicable to gluconeogenic as well as non-gluconeogenic tissues. Applications of these relationships to peripheral ganglia from chicken embryos, in which the 14CO2 difference passes through a maximum during incubation, show that 27-37% of the glucose taken up enters the pentose cycle in sympathetic ganglia from 10-day-old embryos, while 17-36% enters the cycle in 15-day-old dorsal root ganglia.

Metal-based nanoparticle interactions with the nervous system: the challenge of brain entry and the risk of retention in the organism.

PubMed

Yokel, Robert; Grulke, Eric; MacPhail, Robert

2013-01-01

This review of metal-based nanoparticles focuses on factors influencing their distribution into the nervous system, evidence they enter brain parenchyma, and nervous system responses. Gold is emphasized as a model metal-based nanoparticle and for risk assessment in the companion review. The anatomy and physiology of the nervous system, basics of colloid chemistry, and environmental factors that influence what cells see are reviewed to provide background on the biological, physical-chemical, and internal milieu factors that influence nervous system nanoparticle uptake. The results of literature searches reveal little nanoparticle research included the nervous system, which about equally involved in vitro and in vivo methods, and very few human studies. The routes of uptake into the nervous system and mechanisms of nanoparticle uptake by cells are presented with examples. Brain nanoparticle uptake inversely correlates with size. The influence of shape has not been reported. Surface charge has not been clearly shown to affect flux across the blood-brain barrier. There is very little evidence for metal-based nanoparticle distribution into brain parenchyma. Metal-based nanoparticle disruption of the blood-brain barrier and adverse brain changes have been shown, and are more pronounced for spheres than rods. Study concentrations need to be put in exposure contexts. Work with dorsal root ganglion cells and brain cells in vitro show the potential for metal-based nanoparticles to produce toxicity. Interpretation of these results must consider the ability of nanoparticles to distribute across the barriers protecting the nervous system. Effects of the persistence of poorly soluble metal-based nanoparticles are of particular concern. Copyright © 2013 Wiley Periodicals, Inc.

African trypanosome infections of the nervous system: parasite entry and effects on sleep and synaptic functions.

PubMed

Kristensson, Krister; Nygård, Mikael; Bertini, Giuseppe; Bentivoglio, Marina

2010-06-01

The extracellular parasite Trypanosoma brucei causes human African trypanosomiasis (HAT), also known as sleeping sickness. Trypanosomes are transmitted by tsetse flies and HAT occurs in foci in sub-Saharan Africa. The disease, which is invariably lethal if untreated, evolves in a first hemo-lymphatic stage, progressing to a second meningo-encephalitic stage when the parasites cross the blood-brain barrier. At first, trypanosomes are restricted to circumventricular organs and choroid plexus in the brain outside the blood-brain barrier, and to dorsal root ganglia. Later, parasites cross the blood-brain barrier at post-capillary venules, through a multi-step process similar to that of lymphocytes. Accumulation of parasites in the brain is regulated by cytokines and chemokines. Trypanosomes can alter neuronal function and the most prominent manifestation is represented by sleep alterations. These are characterized, in HAT and experimental rodent infections, by disruption of the sleep-wake 24h cycle and internal sleep structure. Trypanosome infections alter also some, but not all, other endogenous biological rhythms. A number of neural pathways and molecules may be involved in such effects. Trypanosomes secrete prostaglandins including the somnogenic PGD2, and they interact with the host's immune system to cause release of pro-inflammatory cytokines. From the sites of early localization of parasites in the brain and meninges, such molecules could affect adjacent brain areas implicated in sleep-wakefulness regulation, including the suprachiasmatic nucleus and its downstream targets, to cause the changes characteristic of the disease. This raises challenging issues on the effects of cytokines on synaptic functions potentially involved in sleep-wakefulness alterations. (c) 2009 Elsevier Ltd. All rights reserved.

Root-hair endophyte stacking in finger millet creates a physicochemical barrier to trap the fungal pathogen Fusarium graminearum.

PubMed

Mousa, Walaa K; Shearer, Charles; Limay-Rios, Victor; Ettinger, Cassie L; Eisen, Jonathan A; Raizada, Manish N

2016-09-26

The ancient African crop, finger millet, has broad resistance to pathogens including the toxigenic fungus Fusarium graminearum. Here, we report the discovery of a novel plant defence mechanism resulting from an unusual symbiosis between finger millet and a root-inhabiting bacterial endophyte, M6 (Enterobacter sp.). Seed-coated M6 swarms towards root-invading Fusarium and is associated with the growth of root hairs, which then bend parallel to the root axis, subsequently forming biofilm-mediated microcolonies, resulting in a remarkable, multilayer root-hair endophyte stack (RHESt). The RHESt results in a physical barrier that prevents entry and/or traps F. graminearum, which is then killed. M6 thus creates its own specialized killing microhabitat. Tn5-mutagenesis shows that M6 killing requires c-di-GMP-dependent signalling, diverse fungicides and resistance to a Fusarium-derived antibiotic. Further molecular evidence suggests long-term host-endophyte-pathogen co-evolution. The end result of this remarkable symbiosis is reduced deoxynivalenol mycotoxin, potentially benefiting millions of subsistence farmers and livestock. Further results suggest that the anti-Fusarium activity of M6 may be transferable to maize and wheat. RHESt demonstrates the value of exploring ancient, orphan crop microbiomes.

Mitochondrial Respiratory Chain Dysfunction in Dorsal Root Ganglia of Streptozotocin-Induced Diabetic Rats and Its Correction by Insulin Treatment

PubMed Central

Chowdhury, Subir K. Roy; Zherebitskaya, Elena; Smith, Darrell R.; Akude, Eli; Chattopadhyay, Sharmila; Jolivalt, Corinne G.; Calcutt, Nigel A.; Fernyhough, Paul

2010-01-01

OBJECTIVE Impairments in mitochondrial physiology may play a role in diabetic sensory neuropathy. We tested the hypothesis that mitochondrial dysfunction in sensory neurons is due to abnormal mitochondrial respiratory function. RESEARCH DESIGN AND METHODS Rates of oxygen consumption were measured in mitochondria from dorsal root ganglia (DRG) of 12- to- 22-week streptozotocin (STZ)-induced diabetic rats, diabetic rats treated with insulin, and age-matched controls. Activities and expression of components of mitochondrial complexes and reactive oxygen species (ROS) were analyzed. RESULTS Rates of coupled respiration with pyruvate + malate (P + M) and with ascorbate + TMPD (Asc + TMPD) in DRG were unchanged after 12 weeks of diabetes. By 22 weeks of diabetes, respiration with P + M was significantly decreased by 31–44% and with Asc + TMPD by 29–39% compared with control. Attenuated mitochondrial respiratory activity of STZ-diabetic rats was significantly improved by insulin that did not correct other indices of diabetes. Activities of mitochondrial complexes I and IV and the Krebs cycle enzyme, citrate synthase, were decreased in mitochondria from DRG of 22-week STZ-diabetic rats compared with control. ROS levels in perikarya of DRG neurons were not altered by diabetes, but ROS generation from mitochondria treated with antimycin A was diminished compared with control. Reduced mitochondrial respiratory function was associated with downregulation of expression of mitochondrial proteins. CONCLUSIONS Mitochondrial dysfunction in sensory neurons from type 1 diabetic rats is associated with impaired rates of respiratory activity and occurs without a significant rise in perikaryal ROS. PMID:20103706

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

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

Surgical intestinal manipulation increases gene expression of TrkA, CGRP, and PAR-2 IN dorsal root ganglia in the rat.

PubMed

Berdún, S; Rychter, J; Vergara, P

2016-06-01

Surgical handling of the bowel evokes degranulation of peritoneal mast cells (PMC). Nonetheless, role of PMCs in postoperative ileus (POI) is somewhat controversial. We aimed to investigate if intestinal manipulation elicits changes in afferent mediators related to MC activation and alteration of gastrointestinal (GI) motility. Postoperative ileus was induced by intestinal manipulation in Sprague-Dawley rats. Additionally, compound 48/80 (C48/80) and ketotifen were used to modulate MC activity. Rat mast cell protease 6 (RMCP-6, ELISA) release was determined in peritoneal lavage 20 min after intestinal manipulation. At 24 h, GI transit was determined. Gene expression of calcitonin gene-related peptide (CGRP), protease-activated receptor-2 (PAR-2), nerve growth factor (NGF), and TrkA receptor was determined (PCR) in dorsal root ganglia (DRG). Ileal wall inflammation was assessed by myeloperoxidase (MPO) activity, interleukin-6 expression (IL-6). Intestinal manipulation and exposure to C48/80-induced degranulation of PMCs delayed GI transit and up-regulated IL-6 and MPO activity. Intestinal manipulation, but not C48/80, up-regulated CGRP, PAR-2, and NGF/TrkA in DRGs. Ketotifen only improved gastric emptying and fecal output. Up-regulation of CGRP and TrkA expression in DRG was not prevented by ketotifen. Postoperative ileus is accompanied by activation of CGRP, NGF-TrkA, and PAR-2 in DRGs. Our results suggest that these mediators could be a target in further POI studies in order to find new therapeutic targets for this medical condition. © 2016 John Wiley & Sons Ltd.

Swimming Training Reduces Neuroma Pain by Regulating Neurotrophins

PubMed Central

TIAN, JINGE; YU, TINGTING; XU, YONGMING; PU, SHAOFENG; LV, YINGYING; ZHANG, XIN; DU, DONGPING

2018-01-01

ABSTRACT Introduction Neuroma formation after peripheral nerve transection leads to severe neuropathic pain in amputees. Previous studies suggested that physical exercise could bring beneficial effect on alleviating neuropathic pain. However, the effect of exercise on neuroma pain still remained unclear. In addition, long-term exercise can affect the expression of neurotrophins (NT), such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), which play key roles in nociceptor sensitization and nerve sprouting after nerve injury. Here, we investigated whether long-term swimming exercise could relieve neuroma pain by modulating NT expression. Methods We used a tibial neuroma transposition (TNT) rat model to mimic neuroma pain. After TNT surgery, rats performed swimming exercise for 5 wk. Neuroma pain and tactile sensitivities were detected using von Frey filaments. Immunofluorescence was applied to analyze neuroma formation. NGF and BDNF expressions in peripheral neuroma, dorsal root ganglion, and the spinal cord were measured using enzyme-linked immunosorbent assay and Western blotting. Results TNT led to neuroma formation, induced neuroma pain, and mechanical allodynia in hind paw. Five-week swimming exercise inhibited neuroma formation and relieved mechanical allodynia in the hind paw and neuroma pain in the lateral ankle. The analgesic effect lasted for at least 1 wk, even when the exercise ceased. TNT elevated the expressions of BDNF and NGF in peripheral neuroma, dorsal root ganglion, and the spinal cord to different extents. Swimming also decreased the elevation of NT expression. Conclusions Swimming exercise not only inhibits neuroma formation induced by nerve transection but also relieves pain behavior. These effects might be associated with the modulation of NT. PMID:28846565

Upregulated TLR3 Promotes Neuropathic Pain by Regulating Autophagy in Rat With L5 Spinal Nerve Ligation Model.

PubMed

Chen, Weijia; Lu, Zhijun

2017-02-01

Microglia, rapidly activated following peripheral nerve injury (PNI), accumulate within the spinal cord and adopt inflammation that contributes to development and maintenance of neuropathic pain. Microglia express functional Toll-like receptors (TLRs), which play pivotal roles in regulating inflammatory processes. However, little is known about the role of TLR3 in regulating neuropathic pain after PNI. Here TLR3 expression and autophagy activation was assayed in dorsal root ganglions and in microglia following PNI by using realtime PCR, western blot and immunohistochemistry. The role of TLR3/autophagy signaling in regulating tactile allodynia was evaluated by assaying paw mechanical withdrawal threshold and cold allodynia after intrathecal administration of Poly (I:C) and 3-methyladenine (3-MA). We found that L5 spinal nerve ligation (SNL) induces the expression of TLR3 in dorsal root ganglions and in primary rat microglia at the mRNA and protein level. Meanwhile, L5 SNL results in an increased activation of autophagy, which contributes to microglial activation and subsequent inflammatory response. Intrathecal administration of Poly (I:C), a TLR3 agonist, significantly increases the activation of microglial autophagy, whereas TLR3 knockdown markedly inhibits L5 SNL-induced microglial autophagy. Poly (I:C) treatment promotes the expression of proinflammatory mediators, whereas 3-MA (a specific inhibitor of autophagy) suppresses Poly (I:C)-induced secretion of proinflammatory cytokines. Autophagy inhibition further inhibits TLR3-mediated mechanical and cold hypersensitivity following SNL. These results suggest that inhibition of TLR3/autophagy signaling contributes to alleviate neurophathic pain triggered by SNL.

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.

Upregulation of Ryk expression in rat dorsal root ganglia after peripheral nerve injury.

PubMed

Li, Xin; Li, Yao-hua; Yu, Shun; Liu, Yaobo

2008-10-22

To study changes of Ryk expression in dorsal root ganglia (DRG) after peripheral nerve injury, we set up an animal model of unilateral sciatic nerve lesioned rats. Changes of Ryk protein expression in DRG neurons after unilateral sciatic nerve injury were investigated by immunostaining. Changes of Ryk mRNA were also tested by semi-quantitative PCR concurrently. We found, both at the level of protein and mRNA, that Ryk could be induced in cells of ipsilateral DRG after unilateral sciatic nerve lesion. Further investigation by co-immunostaining confirmed that the Ryk-immunoreactive (Ryk-IR) cells were NeuN-immunoreactive (NeuN-IR) neurons of DRG. We also showed the pattern of Ryk induction in DRG neurons after sciatic nerve injury: the number of Ryk IR neurons peaked at 2 weeks post-lesion and decreased gradually by 3 weeks post-lesion. The proportions of different sized Ryk IR neurons were also observed and counted at various stages after nerve lesion. Analysis of Ryk mRNA by RT-PCR showed the same induction pattern as by immunostaining. Ryk mRNA was not expressed in normal or contralateral DRG, but was expressed 1, 2 and 3 weeks post-lesion in the ipsilateral DRG. Ryk mRNA levels increased slightly from 1 to 2 weeks, decreased then by 3 weeks post-lesion. These results indicate that Ryk might be involved in peripheral nerve plasticity after injury. This is a novel function apart from its well-known fundamental activity as a receptor mediating axon guidance and outgrowth.

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

Dync1h1 Mutation Causes Proprioceptive Sensory Neuron Loss and Impaired Retrograde Axonal Transport of Dorsal Root Ganglion Neurons.

PubMed

Zhao, Jing; Wang, Yi; Xu, Huan; Fu, Yuan; Qian, Ting; Bo, Deng; Lu, Yan-Xin; Xiong, Yi; Wan, Jun; Zhang, Xiang; Dong, Qiang; Chen, Xiang-Jun

2016-07-01

Sprawling (Swl) is a radiation-induced mutation which has been identified to have a nine base pair deletion in dynein heavy chain 1 (DYNC1H1: encoded by a single gene Dync1h1). This study is to investigate the phenotype and the underlying mechanism of the Dync1h1 mutant. To display the phenotype of Swl mutant mice, we examined the embryos of homozygous (Swl/Swl) and heterozygous (Swl/+) mice and their postnatal dorsal root ganglion (DRG) of surviving Swl/+ mice. The Swl/+ mice could survive for a normal life span, while Swl/Swl could only survive till embryonic (E) 8.5 days. Excessive apoptosis of Swl/+ DRG neurons was revealed during E11.5-E15.5 days, and the peak rate was at E13.5 days. In vitro study of mutated DRG neurons showed impaired retrograde transport of dynein-driven nerve growth factor (NGF). Mitochondria, another dynein-driven cargo, demonstrated much slower retrograde transport velocity in Swl/+ neurons than in wild-type (WT) neurons. Nevertheless, the Swl, Loa, and Cra mutations did not affect homodimerization of DYNC1H1. The Swl/Swl mutation of Dync1h1 gene led to embryonic mal-development and lethality, whereas the Swl/+ DRG neurons demonstrated deficient retrograde transport in dynein-driven cargos and excessive apoptosis during mid- to late-developmental stages. The underlying mechanism of the mutation may not be due to impaired homodimerization of DYNC1H1. © 2016 John Wiley & Sons Ltd.

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.

Standardized Profiling of The Membrane-Enriched Proteome of Mouse Dorsal Root Ganglia (DRG) Provides Novel Insights Into Chronic Pain.

PubMed

Rouwette, Tom; Sondermann, Julia; Avenali, Luca; Gomez-Varela, David; Schmidt, Manuela

2016-06-01

Chronic pain is a complex disease with limited treatment options. Several profiling efforts have been employed with the aim to dissect its molecular underpinnings. However, generated results are often inconsistent and nonoverlapping, which is largely because of inherent technical constraints. Emerging data-independent acquisition (DIA)-mass spectrometry (MS) has the potential to provide unbiased, reproducible and quantitative proteome maps - a prerequisite for standardization among experiments. Here, we designed a DIA-based proteomics workflow to profile changes in the abundance of dorsal root ganglia (DRG) proteins in two mouse models of chronic pain, inflammatory and neuropathic. We generated a DRG-specific spectral library containing 3067 DRG proteins, which enables their standardized quantification by means of DIA-MS in any laboratory. Using this resource, we profiled 2526 DRG proteins in each biological replicate of both chronic pain models and respective controls with unprecedented reproducibility. We detected numerous differentially regulated proteins, the majority of which exhibited pain model-specificity. Our approach recapitulates known biology and discovers dozens of proteins that have not been characterized in the somatosensory system before. Functional validation experiments and analysis of mouse pain behaviors demonstrate that indeed meaningful protein alterations were discovered. These results illustrate how the application of DIA-MS can open new avenues to achieve the long-awaited standardization in the molecular dissection of pathologies of the somatosensory system. Therefore, our findings provide a valuable framework to qualitatively extend our understanding of chronic pain and somatosensation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

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.

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.

Increased TRPV4 expression in urinary bladder and lumbosacral dorsal root ganglia in mice with chronic overexpression of NGF in urothelium.

PubMed

Girard, Beatrice M; Merrill, Liana; Malley, Susan; Vizzard, Margaret A

2013-10-01

Transient receptor potential vanilloid (TRPV) family member 4 (TRPV4) expression has been demonstrated in urothelial cells and dorsal root ganglion (DRG) neurons, and roles in normal micturition reflexes as well as micturition dysfunction have been suggested. TRP channel expression and function is dependent upon target tissue expression of growth factors. These studies expand upon the target tissue dependence of TRPV4 expression in the urinary bladder and lumbosacral DRG using a recently characterized transgenic mouse model with chronic overexpression of nerve growth factor (NGF-OE) in the urothelium. Immunohistochemistry with image analyses, real-time quantitative polymerase chain reaction, and Western blotting were used to determine TRPV4 protein and transcript expression in the urinary bladder (urothelium + suburothelium, detrusor) and lumbosacral DRG from littermate wild-type (WT) and NGF-OE mice. Antibody specificity controls were performed in TRPV4(-/-) mice. TRPV4 transcript and protein expression was significantly (p ≤ 0.001) increased in the urothelium + suburothelium and suburothelial nerve plexus of the urinary bladder and in small- and medium-sized lumbosacral (L1, L2, L6-S1) DRG cells from NGF-OE mice compared to littermate WT mice. NGF-OE mice exhibit significant (p ≤ 0.001) increases in NGF transcript and protein in the urothelium + suburothelium and lumbosacral DRG. These studies demonstrate regulation of TRPV4 expression by NGF in lower urinary tract tissues. Ongoing studies are characterizing the functional roles of TRPV4 expression in the sensory limb (DRG, urothelium) of the micturition reflex.

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

PubMed

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

2015-12-01

Platinum-based anticancer drugs cause peripheral neurotoxicity by damaging sensory neurons within the dorsal root ganglia (DRG), but the mechanisms are incompletely understood. The roles of platinum DNA binding, transcription inhibition and altered cell size were investigated in primary cultures of rat DRG cells. Click chemistry quantitative fluorescence imaging of RNA-incorporated 5-ethynyluridine showed high, but wide ranging, global levels of transcription in individual neurons that correlated with their cell body size. Treatment with platinum drugs reduced neuronal transcription and cell body size to an extent that corresponded to the amount of preceding platinum DNA binding, but without any loss of neuronal cells. The effects of platinum drugs on neuronal transcription and cell body size were inhibited by blocking platinum DNA binding with sodium thiosulfate, and mimicked by treatment with a model transcriptional inhibitor, actinomycin D. In vivo oxaliplatin treatment depleted the total RNA content of DRG tissue concurrently with altering DRG neuronal size. These findings point to a mechanism of chemotherapy-induced peripheral neurotoxicity, whereby platinum DNA damage induces global transcriptional arrest leading in turn to neuronal atrophy. DRG neurons may be particularly vulnerable to this mechanism of toxicity because of their requirements for high basal levels of global transcriptional activity. Findings point to a new stepwise mechanism of chemotherapy-induced peripheral neurotoxicity, whereby platinum DNA damage induces global transcriptional arrest leading in turn to neuronal atrophy. Dorsal root ganglion neurons may be particularly vulnerable to this neurotoxicity because of their high global transcriptional outputs, demonstrated in this study by click chemistry quantitative fluorescence imaging. © 2015 International Society for Neurochemistry.

Comparison of dorsal root ganglion gene expression in rat models of traumatic and HIV-associated neuropathic pain

PubMed Central

Maratou, Klio; Wallace, Victoria C.J.; Hasnie, Fauzia S.; Okuse, Kenji; Hosseini, Ramine; Jina, Nipurna; Blackbeard, Julie; Pheby, Timothy; Orengo, Christine; Dickenson, Anthony H.; McMahon, Stephen B.; Rice, Andrew S.C.

2009-01-01

To elucidate the mechanisms underlying peripheral neuropathic pain in the context of HIV infection and antiretroviral therapy, we measured gene expression in dorsal root ganglia (DRG) of rats subjected to systemic treatment with the anti-retroviral agent, ddC (Zalcitabine) and concomitant delivery of HIV-gp120 to the rat sciatic nerve. L4 and L5 DRGs were collected at day 14 (time of peak behavioural change) and changes in gene expression were measured using Affymetrix whole genome rat arrays. Conventional analysis of this data set and Gene Set Enrichment Analysis (GSEA) was performed to discover biological processes altered in this model. Transcripts associated with G protein coupled receptor signalling and cell adhesion were enriched in the treated animals, while ribosomal proteins and proteasome pathways were associated with gene down-regulation. To identify genes that are directly relevant to neuropathic mechanical hypersensitivity, as opposed to epiphenomena associated with other aspects of the response to a sciatic nerve lesion, we compared the gp120 + ddC-evoked gene expression with that observed in a model of traumatic neuropathic pain (L5 spinal nerve transection), where hypersensitivity to a static mechanical stimulus is also observed. We identified 39 genes/expressed sequence tags that are differentially expressed in the same direction in both models. Most of these have not previously been implicated in mechanical hypersensitivity and may represent novel targets for therapeutic intervention. As an external control, the RNA expression of three genes was examined by RT-PCR, while the protein levels of two were studied using western blot analysis. PMID:18606552

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

Koike, Taro, E-mail: koiket@hirakata.kmu.ac.jp; Wakabayashi, Taketoshi; Mori, Tetsuji

Sox2 is a transcriptional factor expressed in neural stem cells. It is known that Sox2 regulates cell differentiation, proliferation and survival of the neural stem cells. Our previous study showed that Sox2 is expressed in all satellite glial cells of the adult rat dorsal root ganglion. In this study, to examine the role of Sox2 in satellite glial cells, we establish a satellite glial cell-enriched culture system. Our culture method succeeded in harvesting satellite glial cells with the somata of neurons in the dorsal root ganglion. Using this culture system, Sox2 was downregulated by siRNA against Sox2. The knockdown ofmore » Sox2 downregulated ErbB2 and ErbB3 mRNA at 2 and 4 days after siRNA treatment. MAPK phosphorylation, downstream of ErbB, was also inhibited by Sox2 knockdown. Because ErbB2 and ErbB3 are receptors that support the survival of glial cells in the peripheral nervous system, apoptotic cells were also counted. TUNEL-positive cells increased at 5 days after siRNA treatment. These results suggest that Sox2 promotes satellite glial cell survival through the MAPK pathway via ErbB receptors. - Highlights: • We established satellite glial cell culture system. • Function of Sox2 in satellite glial cell was examined using siRNA. • Sox2 knockdown downregulated expression level of ErbB2 and ErbB3 mRNA. • Sox2 knockdown increased apoptotic satellite glial cell. • Sox2 promotes satellite glial cell survival through ErbB signaling.« less

CYTOLOGICAL STUDIES OF ORGANOTYPIC CULTURES OF RAT DORSAL ROOT GANGLIA FOLLOWING X-IRRADIATION IN VITRO

PubMed Central

Masurovsky, Edmund B.; Bunge, Mary Bartlett; Bunge, Richard P.

1967-01-01

Long-term organotypic cultures of rat dorsal root ganglia were exposed to a single 40 kR dose of 184 kvp X-rays and studied in the living and fixed states by light or electron microscopy at 1–14 day intervals thereafter. Within the first 4 days following irradiation, over 30% of the neurons display chromatolytic reactions (eccentric nuclei, peripheral dispersal of Nissl substance, central granular zone) as well as abnormal nucleolar changes and dissociation of ribosomes from endoplasmic reticulum cisternae. Some satellite cells undergo retraction or acute degeneration, leaving only basement membrane to cover the neuron in these areas. 8 days after irradiation, neurons also exhibit (a) areas in which ribosomes are substantially reduced, (b) regions of cytoplasmic sequestration, (c) extensive vacuolization of granular endoplasmic reticulum and Golgi complex, and (d) diversely altered mitochondria (including the presence of ribosome-like particles or association with abnormal glycogen and lipid deposits). Nucleolar components become altered or reoriented and may form abnormal projections and ringlike configurations. Sizeable areas of the neuronal soma are now denuded of satellite cells; underlying these areas, nerve processes are found abnormally invaginated into the neuronal cytoplasm. By the 14th day following irradiation, most neurons display marked degenerative changes including extensive regions of ribosome depletion, sequestration, vacuolization, autolysis, and, in some areas, swirls of filaments, myelin figures, and heterogeneous dense bodies. These observations demonstrate that X-irradiation produces profound cytopathological changes in nervous tissue isolated from the host and that many of these changes resemble the effects of radiation on nervous tissue in vivo. PMID:10976234

INCREASED TRPV4 EXPRESSION IN URINARY BLADDER AND LUMBOSACRAL DORSAL ROOT GANGLIA IN MICE WITH CHRONIC OVEREXPRESSION OF NGF IN UROTHELIUM

PubMed Central

Girard, Beatrice M.; Merrill, Liana; Malley, Susan; Vizzard, Margaret A.

2013-01-01

Transient receptor potential vanilloid (TRPV) family member 4 (TRPV4) expression has been demonstrated in urothelial cells and dorsal root ganglion (DRG) neurons and roles in normal micturition reflexes as well as micturition dysfunction have been suggested. TRP channel expression and function is dependent upon target tissue expression of growth factors. These studies expand upon the target tissue dependence of TRPV4 expression in the urinary bladder and lumbosacral DRG using a recently characterized transgenic mouse model with chronic overexpression of nerve growth factor (NGF-OE) in the urothelium. Immunohistochemistry with image analyses, real-time quantitative polymerase chain reaction (Q-PCR) and western blotting were used to determine TRPV4 protein and transcript expression in the urinary bladder (urothelium + suburothelium, detrusor) and lumbosacral DRG from littermate wildtype (WT) and NGF-OE mice. Antibody specificity controls were performed in TRPV4-/- mice. TRPV4 transcript and protein expression was significantly (p ≤ 0.001) increased in the urothelium + suburothelium and suburothelial nerve plexus of the urinary bladder and in small- and medium-sized lumbosacral (L1, L2, L6-S1) DRG cells from NGF-OE mice compared to littermate WT mice. NGF-OE mice exhibit significant (p ≤ 0.001) increases in NGF transcript and protein in the urothelium + suburothelium and lumbosacral DRG. These studies demonstrate regulation of TRPV4 expression by NGF in lower urinary tract tissues. Ongoing studies are characterizing the functional roles of TRPV4 expression in the sensory limb (DRG, urothelium) of the micturition reflex. PMID:23690258

Suppression of asparaginyl endopeptidase attenuates breast cancer-induced bone pain through inhibition of neurotrophin receptors.

PubMed

Yao, Peng; Ding, Yuanyuan; Han, Zhenkai; Mu, Ying; Hong, Tao; Zhu, Yongqiang; Li, Hongxi

2017-01-01

Objective Cancer-induced bone pain is a common clinical problem in breast cancer patients with bone metastasis. However, the mechanisms driving cancer-induced bone pain are poorly known. Recent studies show that a novel protease, asparaginyl endopeptidase (AEP) plays crucial roles in breast cancer metastasis and progression. We aim to determine the functions and targeted suppress of AEP in a mouse model of breast cancer-induced bone pain. Methods Breast cancer cells with AEP knocked-down or overexpression were constructed and implanted into the intramedullary space of the femur to induce pain-like behavior in mice. AEP-specific inhibitors or purified AEP proteins were further used in animal model. The histological characters of femur and pain ethological changes were measured. The expressions of AEP and neurotrophin receptors (p75NTR and TrkA) in dorsal root ganglion and spinal cord were examined. Results Femur radiographs and histological analysis revealed that cells with AEP knocked-down reduced bone destruction and pain behaviors. However, cells with AEP overexpression elevated bone damage and pain behaviors. Further, Western blot results found that the expressions of p75NTR and TrkA in dorsal root ganglions and spinal cords were reduced in mice inoculated with AEP knocked-down cells. Targeted suppression of AEP with specific small compounds significantly reduced the bone pain while purified recombinant AEP proteins increased bone pain. Conclusions AEP aggravate the development of breast cancer bone metastasis and bone pain by increasing the expression of neurotrophin receptors. AEP might be an effective target for treatment of breast cancerinduced bone pain.

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.

Swimming Training Reduces Neuroma Pain by Regulating Neurotrophins.

PubMed

Tian, Jinge; Yu, Tingting; Xu, Yongming; Pu, Shaofeng; Lv, Yingying; Zhang, Xin; DU, Dongping

2018-01-01

Neuroma formation after peripheral nerve transection leads to severe neuropathic pain in amputees. Previous studies suggested that physical exercise could bring beneficial effect on alleviating neuropathic pain. However, the effect of exercise on neuroma pain still remained unclear. In addition, long-term exercise can affect the expression of neurotrophins (NT), such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), which play key roles in nociceptor sensitization and nerve sprouting after nerve injury. Here, we investigated whether long-term swimming exercise could relieve neuroma pain by modulating NT expression. We used a tibial neuroma transposition (TNT) rat model to mimic neuroma pain. After TNT surgery, rats performed swimming exercise for 5 wk. Neuroma pain and tactile sensitivities were detected using von Frey filaments. Immunofluorescence was applied to analyze neuroma formation. NGF and BDNF expressions in peripheral neuroma, dorsal root ganglion, and the spinal cord were measured using enzyme-linked immunosorbent assay and Western blotting. TNT led to neuroma formation, induced neuroma pain, and mechanical allodynia in hind paw. Five-week swimming exercise inhibited neuroma formation and relieved mechanical allodynia in the hind paw and neuroma pain in the lateral ankle. The analgesic effect lasted for at least 1 wk, even when the exercise ceased. TNT elevated the expressions of BDNF and NGF in peripheral neuroma, dorsal root ganglion, and the spinal cord to different extents. Swimming also decreased the elevation of NT expression. Swimming exercise not only inhibits neuroma formation induced by nerve transection but also relieves pain behavior. These effects might be associated with the modulation of NT.

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.

Virus spread and initial pathological changes in the nervous system in genital herpes simplex virus type 2 infection in mice. A correlative immunohistochemical, light and electron microscopic study.

PubMed

Georgsson, G; Martin, J R; Stoner, G L; Webster, H F

1987-01-01

Mice were infected by the vaginal route with the MS strain of herpes simplex virus type 2 (HSV-2). Serial vaginal cultures were used to confirm infection and to select mice for this study. Two mice were killed by perfusion on days 2-6 post infection (p.i.) and lumbar and sacral cord with cauda were fixed and embedded for electron microscopy. Semithin Epon-sections were stained for viral antigen using a rabbit anti-HSV-2 antiserum and the Avidin-Biotin (ABC) method. Thin sections from antigen-positive blocks were examined by electron microscopy, and the number and types of infected cells detected by these two methods were compared. A good correlation was found between detection of infected cells by these methods. Infected cells included neurons of dorsal root ganglia and spinal cord, satellite cells of dorsal root ganglia, non-myelinating Schwann cells, astrocytes, oligodendrocytes and arachnoidal cells. Infected cells were first detected in the cauda on day 3 p.i. and in the spinal cord on day 5 p.i. The temporal and spatial distribution of infected cells was consistent with neural spread to and within the CNS. The pathological lesions showed a good correlation with the distribution and number of infected cells and are probably due to a direct virus effect. The similar sensitivity of the Epon-ABC method to electron microscopy in detecting infected cells indicates that this method may have useful applications in both experimental and diagnostic work.

Glutamatergic modulation of synaptic-like vesicle recycling in mechanosensory lanceolate nerve terminals of mammalian hair follicles

PubMed Central

Banks, Robert W; Cahusac, Peter M B; Graca, Anna; Kain, Nakul; Shenton, Fiona; Singh, Paramjeet; Njå, Arild; Simon, Anna; Watson, Sonia; Slater, Clarke R; Bewick, Guy S

2013-01-01

Our aim in the present study was to determine whether a glutamatergic modulatory system involving synaptic-like vesicles (SLVs) is present in the lanceolate ending of the mouse and rat hair follicle and, if so, to assess its similarity to that of the rat muscle spindle annulospiral ending we have described previously. Both types of endings are formed by the peripheral sensory terminals of primary mechanosensory dorsal root ganglion cells, so the presence of such a system in the lanceolate ending would provide support for our hypothesis that it is a general property of fundamental importance to the regulation of the responsiveness of the broad class of primary mechanosensory endings. We show not only that an SLV-based system is present in lanceolate endings, but also that there are clear parallels between its operation in the two types of mechanosensory endings. In particular, we demonstrate that, as in the muscle spindle: (i) FM1-43 labels the sensory terminals of the lanceolate ending, rather than the closely associated accessory (glial) cells; (ii) the dye enters and leaves the terminals primarily by SLV recycling; (iii) the dye does not block the electrical response to mechanical stimulation, in contrast to its effect on the hair cell and dorsal root ganglion cells in culture; (iv) SLV recycling is Ca2+ sensitive; and (v) the sensory terminals are enriched in glutamate. Thus, in the lanceolate sensory ending SLV recycling is itself regulated, at least in part, by glutamate acting through a phospholipase D-coupled metabotropic glutamate receptor. PMID:23440964

Transcriptome analysis of dorsal root ganglia's diabetic neuropathy reveals mechanisms involved in pain and regeneration.

PubMed

Athie, Maria Carolina Pedro; Vieira, Andre Schwambach; Teixeira, Juliana Maia; Dos Santos, Gilson Gonçalves; Dias, Elayne Vieira; Tambeli, Claudia Herrera; Sartori, Cesar Renato; Parada, Carlos A

2018-05-08

Peripheral diabetic neuropathy (DN) manifests in nearly 60% of diabetic patients, being pain its most debilitating symptom. Although electrophysiological and morphological aspects are well described, little is known about its development and progression, undermining effective therapies. Hyperglycemia and insulin signaling impairment are considered the triggering events of oxidative stress observed in the dying nerves, however there are still many gaps in the knowledge of intracellular plastic changes it generates. In this study we aimed to evaluate the early transcriptome changes in DN when the first symptoms of the disease start to appear. Next-Generation Sequencing of messenger RNA (RNA-Seq) of L4 and L5 dorsal root ganglia (DRG) four weeks post-diabetes induction in a rat model for type 1 diabetes. RNA sequencing found 66 transcripts differentially expressed between diabetic and control groups, related mainly to the following biological processes: inflammation, hyperalgesia/analgesia, cell growth and cell survival. Given their roles, the differentially expressed genes suggest an attempt to switch to a survival/regenerative program. Our results show that changes in the transcriptome profile start to appear early in the course of DN and might be related to secure cell homeostasis. Hence, the present data may indicate how DRG cells are responding to hyperglycemia in its early stages and which mechanisms first fail to respond, further leading to cell damage and cell death. Early screening of cell alterations in DN might lead to more concrete targets for pharmaceutical interventions, which could more efficiently delay cell damage. Copyright © 2017. Published by Elsevier Inc.

Immunohistochemical demonstration of keratins in the epidermal layers of the Malayan pangolin (Manis javanica), with remarks on the evolution of the integumental scale armour.

PubMed

Meyer, W; Liumsiricharoen, M; Suprasert, A; Fleischer, L G; Hewicker-Trautwein, M

2013-09-16

Using immunohistochemistry, the study demonstrates the distribution of keratins (pan-keratin with CK1-8, 10, 14-16, 19; keratins CK1, 5, 6, 9, 10; hair keratins AE13, AE14) in the epidermis of the Malayan pangolin (Manis javanica). A varying reaction spectrum was observed for pan-keratin, with body region-dependent negative to very strong reaction intensities. The dorsolateral epidermis exhibited positive reactions only in its vital layers, whereas the abdominal epidermis showed strong positive reactions in the soft two outer strata. The single acidic and basic-to-neutral (cyto)keratins produced clear variations compared to the pan-keratin tinging. E.g., CK1 appeared in all epidermal layers of both body regions, except for the ventral stratum corneum, whereas CK5, 6, 9, 10 were restricted to the soft ventral epidermis. Here, distinctly positive reactions were confined to the stratum granulosum, except for CK6 that appeared in the soft stratum corneum. A different staining pattern was obvious for the hair keratins, i.e., positive reactions of AE13 concentrated only in the granular layer of the dorsal epidermis. In the abdominal epidermis, remarkable tinging for AE14 was visible in the stratum basale, decreasing toward the corneal layer, but was also found in the outer root sheath cells of the hair follicles in the ventral body part. Our findings are discussed related to the evolution of the horny dorsal scales of the pangolin, which may have started from the tail root, projecting forward to the head.

Growth hormone regulates the sensitization of developing peripheral nociceptors during cutaneous inflammation

PubMed Central

Liu, Xiaohua; Green, Kathryn J.; Ford, Zachary K.; Queme, Luis F.; Lu, Peilin; Ross, Jessica L.; Lee, Frank B.; Shank, Aaron T.; Hudgins, Renita C.; Jankowski, Michael P.

2016-01-01

Cutaneous inflammation alters the function of primary afferents and gene expression in the affected dorsal root ganglia (DRGs). However specific mechanisms of injury-induced peripheral afferent sensitization and behavioral hypersensitivity during development are not fully understood. Recent studies in children suggest a potential role for growth hormone (GH) in pain modulation. GH modulates homeostasis and tissue repair after injury, but how GH effects nociception in neonates is not known. To determine if GH played a role in modulating sensory neuron function and hyper-responsiveness during skin inflammation in young mice, we examined behavioral hypersensitivity and the response properties of cutaneous afferents using an ex vivo hairy skin-saphenous nerve-dorsal root ganglion (DRG)-spinal cord preparation. Results show that inflammation of the hairy hindpaw skin initiated at either postnatal day 7 (P7) or P14 reduced GH levels specifically in the affected skin. Furthermore, pretreatment of inflamed mice with exogenous GH reversed mechanical and thermal hypersensitivity in addition to altering nociceptor function. These effects may be mediated via an upregulation of insulin-like growth factor 1 receptor (IGFr1) as GH modulated the transcriptional output of IGFr1 in DRG neurons in vitro and in vivo. Afferent-selective knockdown of IGFr1 during inflammation also prevented the observed injury-induced alterations in cutaneous afferents and behavioral hypersensitivity similar to that following GH pretreatment. These results suggest that GH can block inflammation-induced nociceptor sensitization during postnatal development leading to reduced pain-like behaviors, possibly by suppressing the upregulation of IGFr1 within DRGs. PMID:27898492

The antipsychotic drug loxapine is an opener of the sodium-activated potassium channel slack (Slo2.2).

PubMed

Biton, B; Sethuramanujam, S; Picchione, Kelly E; Bhattacharjee, A; Khessibi, N; Chesney, F; Lanneau, C; Curet, O; Avenet, P

2012-03-01

Sodium-activated potassium (K(Na)) channels have been suggested to set the resting potential, to modulate slow after-hyperpolarizations, and to control bursting behavior or spike frequency adaptation (Trends Neurosci 28:422-428, 2005). One of the genes that encodes K(Na) channels is called Slack (Kcnt1, Slo2.2). Studies found that Slack channels were highly expressed in nociceptive dorsal root ganglion neurons and modulated their firing frequency (J Neurosci 30:14165-14172, 2010). Therefore, Slack channel openers are of significant interest as putative analgesic drugs. We screened the library of pharmacologically active compounds with recombinant human Slack channels expressed in Chinese hamster ovary cells, by using rubidium efflux measurements with atomic absorption spectrometry. Riluzole at 500 μM was used as a reference agonist. The antipsychotic drug loxapine and the anthelmintic drug niclosamide were both found to activate Slack channels, which was confirmed by using manual patch-clamp analyses (EC(50) = 4.4 μM and EC(50) = 2.9 μM, respectively). Psychotropic drugs structurally related to loxapine were also evaluated in patch-clamp experiments, but none was found to be as active as loxapine. Loxapine properties were confirmed at the single-channel level with recombinant rat Slack channels. In dorsal root ganglion neurons, loxapine was found to behave as an opener of native K(Na) channels and to increase the rheobase of action potential. This study identifies new K(Na) channel pharmacological tools, which will be useful for further Slack channel investigations.

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.

Advances in understanding of soil biogeochemical cycles: the mechanism of HS entry into the root interior

NASA Astrophysics Data System (ADS)

Aleksandrova, Olga

2017-04-01

Humic substances represent the major reservoir of carbon (C) in ecosystems, and their turnover is crucial for understanding the global C cycle. As shown by some investigators [1-2], the phenomenon of the uptake of the whole humic particles by plant roots is a significant step of biogeochemical cycle of carbon in soils. The mechanism of HS entry the root interior remained unknown for a long time. However recently, the last one was discovered [3]. An advanced model [3] includes two hypotheses. These hypotheses are as follows: (1) each nano-size particle possesses a quantum image that can be revealed as a packet of electromagnetic waves; (2) the interaction of nano-size particle with the membrane (plasma membrane) of living cells, on which it is adsorbed, occurs via the development of the Rayleigh-Taylor (RT) instability on the membrane surface. An advanced model allows us to look insight some into some phenomena that were observed by experiments but remained not understood [2]. The authors [2] applied tritium autoradiography to wheat seedlings cultivated with tritium-labeled HS to consider the uptake of humic particles by plant roots. They found a significant increase in the content of some polar (monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfoquinovosyl diacylglycerol (SQDG) and phosphatidylcholine (PC)) and neutral (free fatty acids, FFA) lipids which were detected in the wheat seedlings treated with humic particles. Authors [2] pointed that lipids MGDG, DGDG, SQDG are crucial for functional and structural integrity of the photosystem complex. Therefore, a stimulating action of adsorbed humic particles evoked phenomena like photosynthesis in root cells that can be interpreted using an advanced model: humic particles being nano-size particles become adsorbed on the plant roots in soils, and influence their micro environment, where they are located, with the specific electromagnetic exposure. Another finding of authors consisted in the uneven partitioning of penetrated humic particles in the root interior as well as a dependence of the amount of penetrated particles on their size. The results showed that the cortex region was colored with the lower intensity of humic particles labeled with tritium, whereas both epiblema and endodermis were darkly colored [2]. An advanced model highlights the uneven partition of penetrated humic particles as a result of the development of RT instability. It seems that instability involves the whole cortex region that results in the delivery of humic particles from epiblema directly to endodermis. A decrease in the amount of penetrated humic particles in dependence on their weight is explained as a gradual loss of the specific quantum property by humic particles with an increase in their size that can be calculated using an approach of quantum biology. References: 1. Smirnov A.I., Yaiumchenko O.E., Golovina H.A., Bekova S.Kh., Lebedev Y.S., EPR Imaging with Natural Spin Probes/ Journal of magnetic resonance, 1991, 91, 386 - 391. 2. Kulikova et al. 2016. Scientific reports | 6:28869| DOI: 10.1038/srep28869 3. Alexanderova O.N. 2016. An advanced model of the viral entry the cell of living organism and its prospect for the future biotechnology in healthcare and pharmaceutics. Conference SGEM, Vienna, November 2016.

Morphological study of the lingual papillae in the ferret (Mustela putorius furo).

PubMed

Takemura, Akimichi; Uemura, Mamoru; Toda, Isumi; Fang, Gang; Hikida, Masaya; Suwa, Fumihiko

2009-05-01

We used four ferrets (Mustela putorius furo) and observed these animals dorsal tongue surface morphology via scanning electron microscope and light microscope. In this investigation, we focused on the food habits and discussed the morphology of the lingual papillae from the viewpoint of comparative anatomy. The ferret has conically-shaped filiform papillae in the posterior, middle and anterior region of the tongue body, and circular-distributed filiform papillae in the lingual apex region. The ferret has fungiform papillae with hemispheric shaped summits in the posterior and middle region with square-shaped summits in the anterior and the lingual apex region. The ferret has V-shaped vallate papillae with eight papillae in two lines or 12 papillae in three lines on the tongue root. No foliate papillae were observed on the dorsal tongue surface of the ferret. The ferret belongs to the carnivore family but has a highly developed vallate papillae which are taste bud papillae and many taste glands. Thus we conclude that the ferrets need a large amount of saliva to swallow food because it demonstrates a large number of taste glands.

[Fractal research of neurite growth in immunofluorescent images].

PubMed

Tang, Min; Wang, Huinan

2008-12-01

Fractal dimension has been widely used in medical images processing and analysis. The neurite growth of cultured dorsal root ganglion (DRG) was detected by fluorescent immunocytochemistry treated with nerve regeneration factor (0.1, 0.5, 2.0 mg/L). A novel method based on triangular prism surface area (TPSA) was introduced and adopted to calculate the fractal dimension of the two-dimensional immunofluorescent images. Experimental results demonstrate that this method is easy to understand and convenient to operate, and the quantititve results are concordant with the observational findings under microscope. This method can be guidelines for analyzing and deciding experimental results.

Isl-1 down-regulates DRG cell proliferation during chicken embryo development.

PubMed

Chen, Dawei; Wang, Guoxin; Luo, Haoshu; Liu, Jiali; Cui, Sheng

2010-01-01

Protein Isl-1 RNA interference and over expression in early chicken embryo dorsal root ganglia (DRG) were used to investigate the function of Isl-1 in DRG cell proliferation. Isl-1 targeted shRNA expression vector and Isl-1 over-expression vector were transfected into chicken embryo DRG by in ovo electroporation. Then, the DRG proliferation rate was detected by BrdU immunohistochemistry. The rate of DRG cell proliferation increased after Isl-1 knock-down and decreased after Isl-1 over-expression. In this study, we found that Isl-1 negatively modulates DRG cell proliferation.

NMNAT1 inhibits axon degeneration via blockade of SARM1-mediated NAD+ depletion

PubMed Central

Sasaki, Yo; Nakagawa, Takashi; Mao, Xianrong; DiAntonio, Aaron; Milbrandt, Jeffrey

2016-01-01

Overexpression of the NAD+ biosynthetic enzyme NMNAT1 leads to preservation of injured axons. While increased NAD+ or decreased NMN levels are thought to be critical to this process, the mechanism(s) of this axon protection remain obscure. Using steady-state and flux analysis of NAD+ metabolites in healthy and injured mouse dorsal root ganglion axons, we find that rather than altering NAD+ synthesis, NMNAT1 instead blocks the injury-induced, SARM1-dependent NAD+ consumption that is central to axon degeneration. DOI: http://dx.doi.org/10.7554/eLife.19749.001 PMID:27735788

Evidence for the tonic inhibition of spinal pain by nicotinic cholinergic transmission through primary afferents

PubMed Central

Matsumoto, Misaki; Xie, Weijiao; Inoue, Makoto; Ueda, Hiroshi

2007-01-01

Background We have proposed that nerve injury-specific loss of spinal tonic cholinergic inhibition may play a role in the analgesic effects of nicotinic acetylcholine receptor (nAChR) agonists on neuropathic pain. However, the tonic cholinergic inhibition of pain remains to be well characterized. Results Here, we show that choline acetyltransferase (ChAT) signals were localized not only in outer dorsal horn fibers (lamina I–III) and motor neurons in the spinal cord, but also in the vast majority of neurons in the dorsal root ganglion (DRG). When mice were treated with an antisense oligodeoxynucleotide (AS-ODN) against ChAT, which decreased ChAT signals in the dorsal horn and DRG, but not in motor neurons, they showed a significant decrease in nociceptive thresholds in paw pressure and thermal paw withdrawal tests. Furthermore, in a novel electrical stimulation-induced paw withdrawal (EPW) test, the thresholds for stimulation through C-, Aδ- and Aβ-fibers were all decreased by AS-ODN-pretreatments. The administration of nicotine (10 nmol i.t.) induced a recovery of the nociceptive thresholds, decreased by the AS-ODN, in the mechanical, thermal and EPW tests. However, nicotine had no effects in control mice or treated with a mismatch scramble (MS)-ODN in all of these nociception tests. Conclusion These findings suggest that primary afferent cholinergic neurons produce tonic inhibition of spinal pain through nAChR activation, and that intrathecal administration of nicotine rescues the loss of tonic cholinergic inhibition. PMID:18088441

Pulsed radiofrequency reduced complete Freund's adjuvant-induced mechanical hyperalgesia via the spinal c-Jun N-terminal kinase pathway.

PubMed

Chen, Kuan-Hung; Yang, Chien-Hui; Juang, Sin-Ei; Huang, Hui-Wen; Cheng, Jen-Kun; Sheen-Chen, Shyr-Ming; Cheng, Jiin-Tsuey; Lin, Chung-Ren

2014-03-01

Pulsed radiofrequency (PRF) treatment involves the pulsed application of a radiofrequency electric field to a nerve. The technology offers pain relief for patients suffering from chronic pain who do not respond well to conventional treatments. We tested whether PRF treatment attenuated complete Freund's adjuvant (CFA) induced inflammatory pain. The profile of spinal c-Jun N-terminal kinases (JNKs) phosphorylation was evaluated to elucidate the potential mechanism. Injection of CFA into the unilateral hind paw of rats induced mechanical hyperalgesia in both the ipsilateral and contralateral hind paws. We administered 500-kHz PRF treatment in 20-ms pulses, at a rate of 2 Hz (2 pulses per second) either to the sciatic nerve in the mid-thigh, or to the L4 anterior primary ramus just distal to the intervertebral foramen in both the CFA group and no-PRF group rats. Tissue samples were examined at 1, 3, 7, and 14 days following PRF treatments. Behavioral studies showed that PRF applied close to the dorsal root ganglion (DRG) significantly attenuated CFA-induced mechanical hyperalgesia compared to no-PRF group (P < .05). And western blotting revealed significant attenuation of the activation of JNK in the spinal dorsal horn compared to no-PRF group animals (P < .05). Application of PRF close to DRG provides an effective treatment for CFA-induced persistent mechanical hyperalgesia by attenuating JNK activation in the spinal dorsal horn.

Sustained neurochemical plasticity in central terminals of mouse DRG neurons following colitis.

PubMed

Benson, Jessica R; Xu, Jiameng; Moynes, Derek M; Lapointe, Tamia K; Altier, Christophe; Vanner, Stephen J; Lomax, Alan E

2014-05-01

Sensitization of dorsal root ganglia (DRG) neurons is an important mechanism underlying the expression of chronic abdominal pain caused by intestinal inflammation. Most studies have focused on changes in the peripheral terminals of DRG neurons in the inflamed intestine but recent evidence suggests that the sprouting of central nerve terminals in the dorsal horn is also important. Therefore, we examine the time course and reversibility of changes in the distribution of immunoreactivity for substance P (SP), a marker of the central terminals of DRG neurons, in the spinal cord during and following dextran sulphate sodium (DSS)-induced colitis in mice. Acute and chronic treatment with DSS significantly increased SP immunoreactivity in thoracic and lumbosacral spinal cord segments. This increase developed over several weeks and was evident in both the superficial laminae of the dorsal horn and in lamina X. These increases persisted for 5 weeks following cessation of both the acute and chronic models. The increase in SP immunoreactivity was not observed in segments of the cervical spinal cord, which were not innervated by the axons of colonic afferent neurons. DRG neurons dissociated following acute DSS-colitis exhibited increased neurite sprouting compared with neurons dissociated from control mice. These data suggest significant colitis-induced enhancements in neuropeptide expression in DRG neuron central terminals. Such neurotransmitter plasticity persists beyond the period of active inflammation and might contribute to a sustained increase in nociceptive signaling following the resolution of inflammation.

Efficacy of transverse tripolar spinal cord stimulator for the relief of chronic low back pain from failed back surgery.

PubMed

Buvanendran, Asokumar; Lubenow, Timothy J

2008-01-01

Failed back surgery syndrome is a common clinical entity for which spinal cord stimulation has been found to be an effective mode of analgesia, but with variable success rates. To determine if focal stimulation of the dorsal columns with a transverse tripolar lead might achieve deeper penetration of the electrical stimulus into the spinal cord and therefore provide greater analgesia to the back. Case report. We describe a 42-year-old female with failed back surgery syndrome that had greater back pain than leg pain. The tripolar lead configuration was achieved by placing percutaneously an octapolar lead in the spinal midline followed by 2 adjacent quadripolar leads, advanced to the T7-T10 vertebral bodies. Tripolar stimulation pattern resulted in more than 70% pain relief in this patient during the screening trial, while stimulation of one or 2 electrodes only provided 20% pain relief. After implantation of a permanent tripolar electrode system with a single rechargeable battery, the pain relief was maintained for one year. This is case report describing a case of a patient with chronic low back pain with a diagnosis of failed back surgery syndrome in which transverse tripolar stimulation using an octapolar and 2 quadripolar leads appeared to be beneficial. The transverse tripolar system consists of a central cathode surrounded by anodes, using 3 leads. This arrangement may contribute to maximum dorsal column stimulation with minimal dorsal root stimulation and provide analgesia to the lower back.

Effects of proinflammatory cytokines on axonal outgrowth from adult rat lumbar dorsal root ganglia using a novel three-dimensional culture system.

PubMed

Kim, Hyunchul; W Caspar, Tyler; Shah, Sameer B; Hsieh, Adam H

2015-08-01

Degeneration of the intervertebral disc is often associated with low back pain and increased infiltration of nerve fibers originating from dorsal root ganglia (DRG). The degenerated disc is also characterized by the presence of proinflammatory cytokines, which may influence axonal outgrowth. Toward an improved understanding of the growth of DRG neurons into compliant extracellular matrices, we developed a novel experimental system to measure axonal outgrowth of adult rat lumbar DRG neurons within three-dimensional (3D) collagen hydrogels and used this system to examine the effects of interleukin 1β (IL-1β) and tumor necrosis factor (TNF)-α treatment. The aim was to investigate the effects of proinflammatory cytokines on 3D neuronal growth into collagen matrices. This was an in vitro study of neurite outgrowth from adult rat lumbar DRG into collagen gels in response to IL-1β and TNF-α. Lumbar DRG were obtained from adult Sprague Dawley rats, bisected to expose cell bodies and placed onto collagen gel constructs prepared in 24-well Transwell inserts. Dorsal root ganglia were then treated with nerve growth factor (NGF)-free Neurobasal media (negative control) or NGF-supplemented media containing 0, 1, and 10 ng/mL of IL-1β and TNF-α. After 7 days, collagen gel-DRG constructs were immunostained for phosphorylated neurofilament, an axonal marker. Simple Neurite Tracer (Fiji/ImageJ) was used to quantify 3D axonal outgrowth from confocal image stacks. Data were analyzed using one-way analysis of variance, with Tukey HSD post hoc correction at a level of p<.05. Immunostaining showed robust axonal outgrowth into collagen gels from all NGF-treated DRG. The negative control demonstrated very few and short neurites. Tumor necrosis factor-α (1 and 10 ng/mL) significantly inhibited axonal outgrowth compared with NGF-only media (p<.026 and p<.02, respectively). After IL-1β treatment, average axon length was 10% lower at 1 ng/mL and 7.5% higher at 10 ng/mL, but these differences were not statistically significant. Among cytokine treatments, however, average axon length in the IL-1β (10 ng/mL) group was significantly higher than that in the other groups (p<.05). A novel 3D collagen gel culture system was used to investigate factors modulating neuronal ingrowth. Our results showed that NGF was necessary to promote neurite growth into collagen gels. In the presence of proinflammatory cytokines, high concentrations of IL-1β induced significantly higher axonal outgrowth than TNF-α and low levels of IL-1β. Copyright © 2015 Elsevier Inc. All rights reserved.

Dorsal hippocampal microinjection of chlorpheniramine reverses the anxiolytic-like effects of l-histidine and impairs emotional memory in mice.

PubMed

Canto-de-Souza, L; Garção, D C; Romaguera, F; Mattioli, R

2015-02-05

Several findings have pointed to the role of histaminergic neurotransmission in the modulation of anxiety-like behaviors and emotional memory. The elevated plus-maze (EPM) test has been widely used to investigate the process of anxiety and also has been used to investigate the process of learning and memory. Visual cues are relevant to the formation of spatial maps, and as the hippocampus is involved in this task, experiment 1 explored this issue. Experiment 2 investigated the effects of intraperitoneal (i.p.) injections of l-histidine (LH, a precursor of histamine) and of intra-dorsal hippocampus (intra-DH) injections of chlorpheniramine (CPA, an H1 receptor antagonist) on anxiety and emotional memory in mice re-exposed to the EPM. Mice received saline (SAL) or LH i.p. and SAL or CPA (0.016, 0.052, and 0.16 nmol/0.1 μl) intra-DH prior to Trial 1 (T1) and Trial 2 (T2). No significant changes were observed in the number of enclosed-arm entries (EAE) in T1, an EPM index of general exploratory activity. LH had an anxiolytic-like effect that was reversed by intra-DH injections of CPA. T2 versus T1 analysis revealed that only the lower dose of CPA resulted in impaired emotional memory. Combined injections of LH and CPA revealed that higher doses of CPA impair emotional memory. Taken together, these results suggest that LH and H1 receptors present in the dorsal hippocampus are involved in anxiety-related behaviors and emotional memory in mice submitted to EPM. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Hair cycle control by leptin as a new anagen inducer.

PubMed

Sumikawa, Yasuyuki; Inui, Shigeki; Nakajima, Takeshi; Itami, Satoshi

2014-01-01

Our purpose is to clarify the physiological role of leptin in hair cycle as leptin reportedly causes activation of Stat3, which is indispensable for hair cycling. While hair follicles in dorsal skin of 5-week-old C57/BL6 mice had progressed to late anagen phase, those in dorsal skin of 5-week-old leptin receptor deficient db/db mice remained in the first telogen and later entered the anagen at postnatal day 40, indicating that deficiency in leptin receptor signalling delayed the second hair cycle progression. Next, we shaved dorsal hairs on wild-type mice at postnatal 7 weeks and injected skin with mouse leptin or a mock. After 20 days, although mock injection showed no effect, hair growth occurred around leptin injection area. Human leptin fragment (aa22-56) had similar effects. Although the hair cycle of ob/ob mice was similar to that of wild-type mice, injection of mouse leptin on ob/ob mice at postnatal 7 weeks induced anagen transition. Immunohistochemically, leptin is expressed in hair follicles from catagen to early anagen in wild-type mice, suggesting that leptin is an anagen inducer in vivo. Phosphorylation of Erk, Jak2 and Stat3 in human keratinocytes was stimulated by leptin and leptin fragment. In addition, RT-PCR and ELISA showed that the production of leptin by human dermal papilla cells increased under hypoxic condition, suggesting that hypoxia in catagen/telogen phase promotes leptin production, preparing for entry into the next anagen. In conclusion, leptin, a well-known adipokine, acts as an anagen inducer and represents a new player in hair biology. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Patterns of motor activity in the isolated nerve cord of the octopus arm.

PubMed

Gutfreund, Yoram; Matzner, Henry; Flash, Tamar; Hochner, Binyamin

2006-12-01

The extremely flexible octopus arm provides a unique opportunity for studying movement control in a highly redundant motor system. We describe a novel preparation that allows analysis of the peripheral nervous system of the octopus arm and its interaction with the muscular and mechanosensory elements of the arm's intrinsic muscular system. First we examined the synaptic responses in muscle fibers to identify the motor pathways from the axial nerve cord of the arm to the surrounding musculature. We show that the motor axons project to the muscles via nerve roots originating laterally from the arm nerve cord. The motor field of each nerve is limited to the region where the nerve enters the arm musculature. The same roots also carry afferent mechanosensory information from the intrinsic muscle to the axial nerve cord. Next, we characterized the pattern of activity generated in the dorsal roots by electrically stimulating the axial nerve cord. The evoked activity, although far reaching and long lasting, cannot alone account for the arm extension movements generated by similar electrical stimulation. The mismatch between patterns of activity in the isolated cord and in an intact arm may stem from the involvement of mechanosensory feedback in natural arm extension.

Structural and functional diversity of CLAVATA3/ESR (CLE)-like genes from the potato cyst nematode Globodera rostochiensis.

PubMed

Lu, Shun-Wen; Chen, Shiyan; Wang, Jianying; Yu, Hang; Chronis, Demosthenis; Mitchum, Melissa G; Wang, Xiaohong

2009-09-01

Plant CLAVATA3/ESR-related (CLE) peptides have diverse roles in plant growth and development. Here, we report the isolation and functional characterization of five new CLE genes from the potato cyst nematode Globodera rostochiensis. Unlike typical plant CLE peptides that contain a single CLE motif, four of the five Gr-CLE genes encode CLE proteins with multiple CLE motifs. These Gr-CLE genes were found to be specifically expressed within the dorsal esophageal gland cell of nematode parasitic stages, suggesting a role for their encoded proteins in plant parasitism. Overexpression phenotypes of Gr-CLE genes in Arabidopsis mimicked those of plant CLE genes, and Gr-CLE proteins could rescue the Arabidopsis clv3-2 mutant phenotype when expressed within meristems. A short root phenotype was observed when synthetic GrCLE peptides were exogenously applied to roots of Arabidopsis or potato similar to the overexpression of Gr-CLE genes in Arabidopsis and potato hairy roots. These results reveal that G. rostochiensis CLE proteins with either single or multiple CLE motifs function similarly to plant CLE proteins and that CLE signaling components are conserved in both Arabidopsis and potato roots. Furthermore, our results provide evidence to suggest that the evolution of multiple CLE motifs may be an important mechanism for generating functional diversity in nematode CLE proteins to facilitate parasitism.

Human Mas-Related G Protein-Coupled Receptors-X1 Induce Chemokine Receptor 2 Expression in Rat Dorsal Root Ganglia Neurons and Release of Chemokine Ligand 2 from the Human LAD-2 Mast Cell Line

PubMed Central

Solinski, Hans Jürgen; Petermann, Franziska; Rothe, Kathrin; Boekhoff, Ingrid; Gudermann, Thomas; Breit, Andreas

2013-01-01

Primate-specific Mas-related G protein-coupled receptors-X1 (MRGPR-X1) are highly enriched in dorsal root ganglia (DRG) neurons and induce acute pain. Herein, we analyzed effects of MRGPR-X1 on serum response factors (SRF) or nuclear factors of activated T cells (NFAT), which control expression of various markers of chronic pain. Using HEK293, DRG neuron-derived F11 cells and cultured rat DRG neurons recombinantly expressing human MRGPR-X1, we found activation of a SRF reporter gene construct and induction of the early growth response protein-1 via extracellular signal-regulated kinases-1/2 known to play a significant role in the development of inflammatory pain. Furthermore, we observed MRGPR-X1-induced up-regulation of the chemokine receptor 2 (CCR2) via NFAT, which is considered as a key event in the onset of neuropathic pain and, so far, has not yet been described for any endogenous neuropeptide. Up-regulation of CCR2 is often associated with increased release of its endogenous agonist chemokine ligand 2 (CCL2). We also found MRGPR-X1-promoted release of CCL2 in a human connective tissue mast cell line endogenously expressing MRGPR-X1. Thus, we provide first evidence to suggest that MRGPR-X1 induce expression of chronic pain markers in DRG neurons and propose a so far unidentified signaling circuit that enhances chemokine signaling by acting on two distinct yet functionally co-operating cell types. Given the important role of chemokine signaling in pain chronification, we propose that interruption of this signaling circuit might be a promising new strategy to alleviate chemokine-promoted pain. PMID:23505557

Bidirectional crosstalk between the sensory and sympathetic motor systems innervating brown and white adipose tissue in male Siberian hamsters.

PubMed

Ryu, Vitaly; Watts, Alan G; Xue, Bingzhong; Bartness, Timothy J

2017-03-01

The brain networks connected to the sympathetic motor and sensory innervations of brown (BAT) and white (WAT) adipose tissues were originally described using two transneuronally transported viruses: the retrogradely transported pseudorabies virus (PRV), and the anterogradely transported H129 strain of herpes simplex virus-1 (HSV-1 H129). Further complexity was added to this network organization when combined injections of PRV and HSV-1 H129 into either BAT or WAT of the same animal generated sets of coinfected neurons in the brain, spinal cord, and sympathetic and dorsal root ganglia. These neurons are well positioned to act as sensorimotor links in the feedback circuits that control each fat pad. We have now determined the extent of sensorimotor crosstalk between interscapular BAT (IBAT) and inguinal WAT (IWAT). PRV152 and HSV-1 H129 were each injected into IBAT or IWAT of the same animal: H129 into IBAT and PRV152 into IWAT. The reverse configuration was applied in a different set of animals. We found single-labeled neurons together with H129+PRV152 coinfected neurons in multiple brain sites, with lesser numbers in the sympathetic and dorsal root ganglia that innervate IBAT and IWAT. We propose that these coinfected neurons mediate sensory-sympathetic motor crosstalk between IBAT and IWAT. Comparing the relative numbers of coinfected neurons between the two injection configurations showed a bias toward IBAT-sensory and IWAT-sympathetic motor feedback loops. These coinfected neurons provide a neuroanatomical framework for functional interactions between IBAT thermogenesis and IWAT lipolysis that occurs with cold exposure, food restriction/deprivation, exercise, and more generally with alterations in adiposity. Copyright © 2017 the American Physiological Society.

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

PubMed

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

2008-09-10

We compared the distribution of the alpha-subunit mRNAs of voltage-gated sodium channels Nav1.1-1.3 and Nav1.6-1.9 and a related channel, Nax, in histochemically identified neuronal subpopulations of the rat dorsal root ganglia (DRG). In the naïve DRG, the expression of Nav1.1 and Nav1.6 was restricted to A-fiber neurons, and they were preferentially expressed by TrkC neurons, suggesting that proprioceptive neurons possess these channels. Nav1.7, -1.8, and -1.9 mRNAs were more abundant in C-fiber neurons compared with A-fiber ones. Nax was evenly expressed in both populations. Although Nav1.8 and -1.9 were preferentially expressed by TrkA neurons, other alpha-subunits were expressed independently of TrkA expression. Actually, all IB4(+) neurons expressed both Nav1.8 and -1.9, and relatively limited subpopulations of IB4(+) neurons (3% and 12%, respectively) expressed Nav1.1 and/or Nav1.6. These findings provide useful information in interpreting the electrophysiological characteristics of some neuronal subpopulations of naïve DRG. After L5 spinal nerve ligation, Nav1.3 mRNA was up-regulated mainly in A-fiber neurons in the ipsilateral L5 DRG. Although previous studies demonstrated that nerve growth factor (NGF) and glial cell-derived neurotrophic factor (GDNF) reversed this up-regulation, the Nav1.3 induction was independent of either TrkA or GFRalpha1 expression, suggesting that the induction of Nav1.3 may be one of the common responses of axotomized DRG neurons without a direct relationship to NGF/GDNF supply. (c) 2008 Wiley-Liss, Inc.

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.

Ethanol Reversal of Oxycodone Tolerance in Dorsal Root Ganglia Neurons.

PubMed

Jacob, Joanna C; Sakakibara, Kensuke; Mischel, Ryan A; Henderson, Graeme; Dewey, William L; Akbarali, Hamid I

2018-05-01

Oxycodone is a semisynthetic opioid compound that is widely prescribed, used, and abused today, and has a well-established role in shaping the current opioid epidemic. Previously, we have shown that tolerance develops to the antinociceptive and respiratory depressive effects of oxycodone in mice, and that a moderate dose of acute ethanol or a protein kinase C (PKC) inhibitor reversed that tolerance. To investigate further if tolerance was occurring through neuronal mechanisms, our aims for this study were to assess the effects of acute and prolonged oxycodone in isolated dorsal root ganglia (DRG) neurons and to determine if this tolerance was reversed by either ethanol or a PKC inhibitor. We found that an acute exposure to 3 μ M oxycodone reduced neuronal excitability, as measured by increased threshold potentials and reduced action potential amplitude, without eliciting measurable changes in resting membrane potential. Exposure to 10 μ M oxycodone for 18-24 hours prevented oxycodone's effect on neuronal excitability, indicative of tolerance development. The development of opioid tolerance was mitigated in DRG neurons from β -arrestin 2 knockout mice. Oxycodone tolerance was reversed in isolated DRG neurons by the acute application of either ethanol (20 mM) or the PKC inhibitor, bisindolylmaleimide XI hydrochloride (Bis XI), when a challenge of 3 µ M oxycodone significantly reduced neuronal excitability following prolonged exposure. Through these studies, we concluded that oxycodone acutely reduced neuronal excitability, tolerance developed to this effect, and reversal of that tolerance occurred at the level of a single neuron, suggesting that reversal of oxycodone tolerance by either ethanol or Bis XI involves cellular mechanisms. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Different types of spinal afferent nerve endings in stomach and esophagus identified by anterograde tracing from dorsal root ganglia.

PubMed

Spencer, Nick J; Kyloh, Melinda; Beckett, Elizabeth A; Brookes, Simon; Hibberd, Tim

2016-10-15

In visceral organs of mammals, most noxious (painful) stimuli as well as innocuous stimuli are detected by spinal afferent neurons, whose cell bodies lie in dorsal root ganglia (DRGs). One of the major unresolved questions is the location, morphology, and neurochemistry of the nerve endings of spinal afferents that actually detect these stimuli in the viscera. In the upper gastrointestinal (GI) tract, there have been many anterograde tracing studies of vagal afferent endings, but none on spinal afferent endings. Recently, we developed a technique that now provides selective labeling of only spinal afferents. We used this approach to identify spinal afferent nerve endings in the upper GI tract of mice. Animals were anesthetized, and injections of dextran-amine were made into thoracic DRGs (T8-T12). Seven days post surgery, mice were euthanized, and the stomach and esophagus were removed, fixed, and stained for calcitonin gene-related peptide (CGRP). Spinal afferent axons were identified that ramified extensively through many rows of myenteric ganglia and formed nerve endings in discrete anatomical layers. Most commonly, intraganglionic varicose endings (IGVEs) were identified in myenteric ganglia of the stomach and varicose simple-type endings in the circular muscle and mucosa. Less commonly, nerve endings were identified in internodal strands, blood vessels, submucosal ganglia, and longitudinal muscle. In the esophagus, only IGVEs were identified in myenteric ganglia. No intraganglionic lamellar endings (IGLEs) were identified in the stomach or esophagus. We present the first identification of spinal afferent endings in the upper GI tract. Eight distinct types of spinal afferent endings were identified in the stomach, and most of them were CGRP immunoreactive. J. Comp. Neurol. 524:3064-3083, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Paclitaxel-induced painful neuropathy is associated with changes in mitochondrial bioenergetics, glycolysis, and an energy deficit in dorsal root ganglia neurons

PubMed Central

Duggett, Natalie A.; Griffiths, Lisa A.; Flatters, Sarah J.L.

2017-01-01

Abstract Painful neuropathy is the major dose-limiting side effect of paclitaxel chemotherapy. Mitochondrial dysfunction and adenosine triphosphate (ATP) deficit have previously been shown in peripheral nerves of paclitaxel-treated rats, but the effects of paclitaxel in the dorsal root ganglia (DRGs) have not been explored. The aim of this study was to determine the bioenergetic status of DRG neurons following paclitaxel exposure in vitro and in vivo. Utilising isolated DRG neurons, we measured respiratory function under basal conditions and at maximal capacity, glycolytic function, and Adenosine diphosphate (ADP)/ATP levels at 3 key behavioural timepoints; prior to pain onset (day 7), peak pain severity and pain resolution. At day 7, maximal respiration and spare reserve capacity were significantly decreased in DRG neurons from paclitaxel-treated rats. This was accompanied by decreased basal ATP levels and unaltered ADP levels. At peak pain severity, respiratory function was unaltered, yet glycolytic function was significantly increased. Reduced ATP and unaltered ADP levels were also observed at the peak pain timepoint. All these effects in DRG neurons had dissipated by the pain resolution timepoint. None of these paclitaxel-evoked changes could be replicated from in vitro paclitaxel exposure to naive DRG neurons, demonstrating the impact of in vivo exposure and the importance of in vivo models. These data demonstrate the nature of mitochondrial dysfunction evoked by in vivo paclitaxel in the DRG for the first time. Furthermore, we have identified paclitaxel-evoked changes in the bioenergetics of DRG neurons, which result in a persistent energy deficit that is causal to the development and maintenance of paclitaxel-induced pain. PMID:28541258

Spike propagation through the dorsal root ganglia in an unmyelinated sensory neuron: a modeling study

PubMed Central

Sundt, Danielle; Gamper, Nikita

2015-01-01

Unmyelinated C-fibers are a major type of sensory neurons conveying pain information. Action potential conduction is regulated by the bifurcation (T-junction) of sensory neuron axons within the dorsal root ganglia (DRG). Understanding how C-fiber signaling is influenced by the morphology of the T-junction and the local expression of ion channels is important for understanding pain signaling. In this study we used biophysical computer modeling to investigate the influence of axon morphology within the DRG and various membrane conductances on the reliability of spike propagation. As expected, calculated input impedance and the amplitude of propagating action potentials were both lowest at the T-junction. Propagation reliability for single spikes was highly sensitive to the diameter of the stem axon and the density of voltage-gated Na+ channels. A model containing only fast voltage-gated Na+ and delayed-rectifier K+ channels conducted trains of spikes up to frequencies of 110 Hz. The addition of slowly activating KCNQ channels (i.e., KV7 or M-channels) to the model reduced the following frequency to 30 Hz. Hyperpolarization produced by addition of a much slower conductance, such as a Ca2+-dependent K+ current, was needed to reduce the following frequency to 6 Hz. Attenuation of driving force due to ion accumulation or hyperpolarization produced by a Na+-K+ pump had no effect on following frequency but could influence the reliability of spike propagation mutually with the voltage shift generated by a Ca2+-dependent K+ current. These simulations suggest how specific ion channels within the DRG may contribute toward therapeutic treatments for chronic pain. PMID:26334005

[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.

[Effect of partial ganglionectomy and acupuncture on culturing spared DRG in vitro].

PubMed

Wang, Te-Wei; Wang, Ting-Hua; Zhou, Xue; Zhang, Lian-Shuang; Xu, Xin-Yun

2005-09-01

To explore the effect of partial dorsal root rhizotomy and Acup on culturing dorsal root ganglion(DRG) in vitro. Ten adult cats were divided into 2 groups: normal control group; Acup spared DRG 7 d group, in which bilateral L1-L5, L7-S2 DRG were removed; and L6DRG were spared; then unilaterally two sets of acupoints [Zusanlily (St. 36) and Xuanzhong (G. B. 39): Futu (St. 32) and Sanyinjiao (Sp. 6) located in the distribution area of spinal nerve L6] were electro-stimulated alternatively 30 min everyday by electro-needling. Five cats were used in every group. Bilateral L6 DRGs of every group were taken out on the condition of asepsis and were cultured respectively in vitro. Cultures were terminated after day 7. Then the cultured cells were stained under the same condition using specific NSE (1 : 200) antibody, a neuron-specific marker, by the immunohistochemistry ABC method. The neurite length was measured by micro-measured ruler in upside-down light microscope on the 1st, 3rd, 5th, 7th day. Immunocytochemical staining revealed that over 95% cells were NSE positive cells which were the typical neuron of DRG in vitro; on the 1st, 3rd, 5th, 7th day, the average neurite length of the normal group was shorter than that of the spared DRG group(P < 0. 05), and the spared DRG group's was shorter than the Acup group's at each time stage (P < 0.05). These results indicated that DRG had plasticity and acupuncture probably promoted the plasticity, which were probably in close relation with the spinal plasticity.

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

Effects of Hindlimb Unweighting on MBP and GDNF Expression and Morphology in Rat Dorsal Root Ganglia Neurons.

PubMed

Zhang, Heng; Ren, Ning-Tao; Zhou, Fang-Qiang; Li, Jie; Lei, Wei; Liu, Ning; Bi, Long; Wu, Zi-Xiang; Zhang, Ran; Zhang, Yong-Gang; Cui, Geng

2016-09-01

With the development of technology and space exploration, studies on long-duration space flights have shown that microgravity induces damage to multiple organs, including the dorsal root ganglia (DRG). However, very little is known about the effects of long-term microgravity on DRG neurons. This study investigated the effects of microgravity on lumbar 5 (L5) DRG neurons in rats using the hindlimb unweighting (HU) model. Male (M) and female (F) Sprague-Dawley rats were randomly divided into M- and F-control (CON) groups and M- and F-HU groups, respectively (n = 10). At the end of HU treatment for 4 weeks, morphological changes were detected. Myelin basic protein (MBP) and degenerated myelin basic protein (dgen-MBP) expressions were analyzed by immunofluorescence and western blot assays. Glial cell line-derived neurotrophic factor (GDNF) protein and mRNA expressions were also analyzed by immunohistochemistry, western blot, and RT-PCR analysis, respectively. Compared with the corresponding CON groups, the HU groups exhibited slightly loose junctions between DRG neurons, some separated ganglion cells and satellite cells, and lightly stained Nissl bodies that were of smaller size and had a scattered distribution. High levels of dgen-MBP and low MBP expressions were appeared and GDNF expressions were significantly decreased in both HU groups. Changes were more pronounced in the F-HU group than in the M-HU group. In conclusion, HU treatment induced damage of L5 DRG neurons, which was correlated with decreased total MBP protein expression, increased dgen-MBP expression, and reduced GDNF protein and mRNA expression. Importantly, these changes were more severe in F-HU rats compared with M-HU rats.

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.

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

Purification and culture of adult rat dorsal root ganglia neurons.

PubMed

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

1989-06-01

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

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.

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

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.

Dopamine modulation of transient receptor potential vanilloid type 1 (TRPV1) receptor in dorsal root ganglia neurons.

PubMed

Chakraborty, Saikat; Rebecchi, Mario; Kaczocha, Martin; Puopolo, Michelino

2016-03-15

The transient receptor potential vanilloid type 1 (TRPV1) receptor plays a key role in the modulation of nociceptor excitability. To address whether dopamine can modulate the activity of TRPV1 channels in nociceptive neurons, the effects of dopamine and dopamine receptor agonists were tested on the capsaicin-activated current recorded from acutely dissociated small diameter (<27 μm) dorsal root ganglia (DRG) neurons. Dopamine or SKF 81297 (an agonist at D1/D5 receptors), caused inhibition of both inward and outward currents by ∼60% and ∼48%, respectively. The effect of SKF 81297 was reversed by SCH 23390 (an antagonist at D1/D5 receptors), confirming that it was mediated by activation of D1/D5 dopamine receptors. In contrast, quinpirole (an agonist at D2 receptors) had no significant effect on the capsaicin-activated current. Inhibition of the capsaicin-activated current by SKF 81297 was mediated by G protein coupled receptors (GPCRs), and highly dependent on external calcium. The inhibitory effect of SKF 81297 on the capsaicin-activated current was not affected when the protein kinase A (PKA) activity was blocked with H89, or when the protein kinase C (PKC) activity was blocked with bisindolylmaleimide II (BIM). In contrast, when the calcium-calmodulin-dependent protein kinase II (CaMKII) was blocked with KN-93, the inhibitory effect of SKF 81297 on the capsaicin-activated current was greatly reduced, suggesting that activation of D1/D5 dopamine receptors may be preferentially linked to CaMKII activity. We suggest that modulation of TRPV1 channels by dopamine in nociceptive neurons may represent a way for dopamine to modulate incoming noxious stimuli. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

HMG-CoA synthase isoenzymes 1 and 2 localize to satellite glial cells in dorsal root ganglia and are differentially regulated by peripheral nerve injury.

PubMed

Wang, Fei; Xiang, Hongfei; Fischer, Gregory; Liu, Zhen; Dupont, Matthew J; Hogan, Quinn H; Yu, Hongwei

2016-12-01

In dorsal root ganglia (DRG), satellite glial cells (SGCs) tightly ensheathe the somata of primary sensory neurons to form functional sensory units. SGCs are identified by their flattened and irregular morphology and expression of a variety of specific marker proteins. In this report, we present evidence that the 3-hydroxy-3-methylglutaryl coenzyme A synthase isoenzymes 1 and 2 (HMGCS1 and HMGCS2) are abundantly expressed in SGCs. Immunolabeling with the validated antibodies revealed that both HMGCS1 and HMGCS2 are highly colabeled with a selection of SGC markers, including GS, GFAP, K ir 4.1, GLAST1, GDNF, and S100 but not with microglial cell marker Iba1, myelin sheath marker MBP, and neuronal marker β3-tubulin or phosphorylated CaMKII. HMGCS1 but not HMGCS2 immunoreactivity in SGCs is reduced in the fifth lumbar (L5) DRGs that contain axotomized neurons following L5 spinal nerve ligation (SNL) in rats. Western blot showed that HMGCS1 protein level in axotomized L5 DRGs is reduced after SNL to 66±8% at 3 days (p<0.01, n=4 animals in each group) and 58±13% at 28 days (p<0.001, n=9 animals in each group) of its level in control samples, whereas HMGCS2 protein was comparable between injured and control DRGs. These results identify HMGCSs as the alternative markers for SGCs in DRGs. Downregulated HMGCS1 expression in DRGs after spinal nerve injury may reflect a potential role of abnormal sterol metabolism of SGCs in the nerve injured-induced neuropathic pain. Copyright © 2016 Elsevier B.V. All rights reserved.