scholarly journals Dorsal Root Ganglion Neurons Innervating Skeletal Muscle Respond to Physiological Combinations of Protons, ATP, and Lactate Mediated by ASIC, P2X, and TRPV1

2008 ◽  
Vol 100 (3) ◽  
pp. 1184-1201 ◽  
Author(s):  
Alan R. Light ◽  
Ronald W. Hughen ◽  
Jie Zhang ◽  
Jon Rainier ◽  
Zhuqing Liu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Dorsal Root Ganglion ◽  
Calcium Imaging ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Drg Neurons ◽  
Molecular Receptors ◽  
Trpv1 Receptors ◽  
Ganglion Neurons ◽  
Two Populations

The adequate stimuli and molecular receptors for muscle metaboreceptors and nociceptors are still under investigation. We used calcium imaging of cultured primary sensory dorsal root ganglion (DRG) neurons from C57Bl/6 mice to determine candidates for metabolites that could be the adequate stimuli and receptors that could detect these stimuli. Retrograde DiI labeling determined that some of these neurons innervated skeletal muscle. We found that combinations of protons, ATP, and lactate were much more effective than individually applied compounds for activating rapid calcium increases in muscle-innervating dorsal root ganglion neurons. Antagonists for P2X, ASIC, and TRPV1 receptors suggested that these three receptors act together to detect protons, ATP, and lactate when presented together in physiologically relevant concentrations. Two populations of muscle-innervating DRG neurons were found. One responded to low metabolite levels (likely nonnoxious) and used ASIC3, P2X5, and TRPV1 as molecular receptors to detect these metabolites. The other responded to high levels of metabolites (likely noxious) and used ASIC3, P2X4, and TRPV1 as their molecular receptors. We conclude that a combination of ASIC, P2X5 and/or P2X4, and TRPV1 are the molecular receptors used to detect metabolites by muscle-innervating sensory neurons. We further conclude that the adequate stimuli for muscle metaboreceptors and nociceptors are combinations of protons, ATP, and lactate.

GABAA-receptor-activated current in dorsal root ganglion neurons freshly isolated from adult rats

1990 ◽  
Vol 64 (1) ◽  
pp. 57-63 ◽  
Author(s):  
G. White
Keyword(s):  
Dorsal Root Ganglion ◽  
Action Potential ◽  
Gabaa Receptor ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Drg Neurons ◽  
Ganglion Neurons ◽  
Two Populations

1. gamma-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter affecting dorsal root ganglion (DRG) neurons. This study compares properties of current activated by the GABAA receptor in two populations of DRG neurons. DRG neurons were isolated from adult rat with the use of enzymatic and mechanical means. Within hours of being isolated, neurons were recorded from with the use of the whole-cell variant of the patch-clamp technique. 2. One population of neurons exhibited an afterdepolarizing potential (ADP), a low threshold for action-potential generation (-45 to -50 mV), a short-duration action potential (less than 2 ms) that was abolished in the presence of 1-2 microM tetrodotoxin (TTX), and an insensitivity to 50 nM capsaicin. The second population of neurons exhibited a high threshold for action-potential generation (less than -40 mV), a shoulder on the falling phase of the action potential, insensitivity of action-potential generation to TTX (1-2 microM), and a depolarizing response to application of 50 nM capsaicin. 3. Sensitivity to GABA (over the range of 1–1,000 microM) was comparable for the two populations of neurons. 4. GABA-activated current was greater in ADP neurons than in non-ADP-type neurons of a comparable diameter (30-50 microns). The mean +/- SE amplitude of current activated by 10 microM GABA in ADP neurons was 0.310 +/- 0.050 nA (range = 0.110-0.460 nA, n = 8), and 0.037 +/- 0.016 nA (range = 0.010-0.130 pA, n = 7) in non-ADP neurons. Ten microM GABA elicited cell firing in ADP neurons but not in non-ADP neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Parvalbumin and TRPV1 receptor expression in dorsal root ganglion neurons after acute peripheral inflammation

2009 ◽  
pp. 305-309 ◽  
Author(s):  
G Zachařová ◽  
J Paleček
Keyword(s):  
Dorsal Root Ganglion ◽  
Synaptic Transmission ◽  
Dorsal Root ◽  
Receptor Expression ◽  
Dorsal Root Ganglion Neurons ◽  
Peripheral Inflammation ◽  
Transient Receptor Potential Vanilloid ◽  
Drg Neurons ◽  
Trpv1 Receptors ◽  
Ganglion Neurons

Expression of parvalbumin (PV) and transient receptor potential vanilloid (TRPV1) receptors in the lumbar dorsal root ganglion neurons (DRG) was evaluated in control animals and in rats after acute carageenan-induced knee joint inflammation. PV is a calcium binding protein that acts as a calcium buffer, affects intracellular calcium homeostasis and may thus influence signal transduction and synaptic transmission. TRPV1 receptors are viewed as molecular integrators of nociceptive stimuli and modulate spinal cord synaptic transmission beside their function in the peripheral nerve endings. In naive rats, 13 % of the L4 DRG neurons had PV immunopositivity (PV+) and 36 % expressed TRPV1 receptors (TRPV1+). The soma of the PV+ neurons was of medium to large size, while the TRPV1 receptors were expressed in small diameter neurons. The co-localization of the PV and TRPV1 immunoreactivity was minimal (0.2 %). There was no significant change in the PV+ (11 %), TRPV1+ (42 %) and PV+TRPV1+ (0.25 %) expression, or shift in the neuronal size distribution 28 h after the unilateral peripheral inflammation, both when compared to controls and when ipsilateral to contralateral sides were evaluated. Thus under the given experimental conditions, no change in somatic TRPV1 receptors and PV expression in L4 DRG neurons was found.

scholarly journals On the inhibition of capsaicin response in dorsal root ganglion neurons by nobilamide B and analogues: a structure–activity relationship study

MedChemComm ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 1673-1678
Author(s):  
Oliver John V. Belleza ◽  
Jortan O. Tun ◽  
Gisela P. Concepcion ◽  
Aaron Joseph L. Villaraza
Keyword(s):  
Dorsal Root Ganglion ◽  
Primary Culture ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
Activity Relationship ◽  
Drg Neurons ◽  
Structure Activity ◽  
Relationship Study ◽  
Trpv1 Antagonist ◽  
Ganglion Neurons

Nobilamide B, a TRPV1 antagonist, and a series of Ala-substituted analogues were synthesized and their neuroactivity was assessed in a primary culture of dorsal root ganglion (DRG) neurons.

Variation in IH, IIR, and ILEAK between acutely isolated adult rat dorsal root ganglion neurons of different size

1994 ◽  
Vol 71 (1) ◽  
pp. 271-279 ◽  
Author(s):  
R. S. Scroggs ◽  
S. M. Todorovic ◽  
E. G. Anderson ◽  
A. P. Fox
Keyword(s):  
Dorsal Root Ganglion ◽  
Action Potentials ◽  
Dorsal Root ◽  
Membrane Surface ◽  
Small Diameter ◽  
Reversal Potential ◽  
Dorsal Root Ganglion Neurons ◽  
Time Dependent ◽  
Drg Neurons ◽  
Ganglion Neurons

1. The distribution of IH, IIR, and ILEAK was studied in different diameter rat dorsal root ganglion (DRG) neuron cell bodies (neurons). DRG neurons were studied in three diameter ranges: small (19–27 microns), medium (33–37 microns), and large (44-54 microns). IH was defined as a slowly activating inward current evoked by hyperpolarizing voltage steps from a holding potential (HP) of -60 mV, and blocked by 1 mM Cs2+ but not 1 mM Ba2+. Inward rectifier current (IIR) was defined as a rapidly activating current evoked by hyperpolarizations from HP -60 mV, which rectified inwardly around the reversal potential for potassium (EK), and was completely blocked by 100 microM Ba2+. ILEAK was defined as an outward resting current at HP -60 mV, which did not rectify and was blocked by 100 microM Ba2+ but not by 2 mM Cs+. 2. IH was observed in 23 of 23 large, 11 of 12 medium, and in 9 of 20 small diameter DRG neurons tested. Peak IH normalized to membrane surface area was significantly greater in large than in medium or small diameter DRG neurons expressing IH. All neurons exhibiting IH under voltage clamp conditions had short duration action potentials and exhibited time-dependent rectification under current clamp conditions, properties similar to A-type DRG neurons. The 11 small diameter neurons not expressing IH had long duration action potentials and did not exhibit time-dependent rectification, properties similar to C-type DRG neurons. 3. IIR was detected in 18 of 22 medium diameter neurons tested.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals An integrated cell isolation and purification method for rat dorsal root ganglion neurons

2019 ◽  
Vol 47 (7) ◽  
pp. 3253-3260
Author(s):  
Huaishuang Shen ◽  
Minfeng Gan ◽  
Huilin Yang ◽  
Jun Zou
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Root Ganglion ◽  
Primary Culture ◽  
Dorsal Root ◽  
Cell Isolation ◽  
Dorsal Root Ganglion Neurons ◽  
Drg Neurons ◽  
Purification Method ◽  
Isolation And Purification ◽  
Ganglion Neurons

Objective Neurobiology studies are increasingly focused on the dorsal root ganglion (DRG), which plays an important role in neuropathic pain. Existing DRG neuron primary culture methods have considerable limitations, including challenging cell isolation and poor cell yield, which cause difficulty in signaling pathway studies. The present study aimed to establish an integrated primary culture method for DRG neurons. Methods DRGs were obtained from fetal rats by microdissection, and then dissociated with trypsin. The dissociated neurons were treated with 5-fluorouracil to promote growth of neurons from the isolated cells. Then, reverse transcription polymerase chain reaction and immunofluorescence assays were used to identify and purify DRG neurons. Results Isolated DRGs were successfully dissociated and showed robust growth as individual DRG neurons in neurobasal medium. Both mRNA and protein assays confirmed that DRG neurons expressed neurofilament-200 and neuron-specific enolase. Conclusions Highly purified, stable DRG neurons could be easily harvested and grown for extended periods by using this integrated cell isolation and purification method, which may help to elucidate the mechanisms underlying neuropathic pain.

Interaction of opioids and membrane potential to modulate Ca2+ channels in rat dorsal root ganglion neurons

1995 ◽  
Vol 73 (5) ◽  
pp. 1793-1798 ◽  
Author(s):  
M. D. Womack ◽  
E. W. McCleskey
Keyword(s):  
Dorsal Root Ganglion ◽  
Sensory Neurons ◽  
Action Potentials ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
High Threshold ◽  
Partial Recovery ◽  
Drg Neurons ◽  
Ganglion Neurons ◽  
Ca2 Channels

1. Using patch-clamp methods, we show that brief prepulses to very positive voltages increase (facilitate) the amplitude of current through Ca2+ channels during a subsequent test pulse in some, but not all, dorsal root ganglion (DRG) sensory neurons. The amplitude of this facilitated current generally increases when the Ca2+ channels are inhibited by activation of the mu-opioid receptor. 2. The facilitated current is blocked by omega-conotoxin GVIA, activates in the range of high-threshold Ca2+ channels, and inactivates at relatively negative holding voltages. Thus facilitated current passes through N-type Ca2+ channels, the same channels that are inhibited by opioids and control neurotransmitter release in sensory neurons. 3. Although maximal facilitation occurs only at unphysiologically high membrane potentials (above +100 mV), some facilitation is seen after prepulses to voltages reached during action potentials. After return to the holding potential, facilitation persists for hundreds of milliseconds, considerably longer than in other neurons. Brief trains of pulses designed to mimic action potentials caused small facilitation (19% of maximal) in a fraction (8 of 24) of opioid-inhibited neurons. 4. We conclude that 1) prepulses to extremely positive voltages can cause partial recovery of Ca2+ channels inhibited by opioids; and 2) small, but detectable, facilitation is also seen after physiological stimulation in some DRG neurons. Facilitation, largely considered a biophysical epiphenomenon because of the extreme voltages used to induce it, appears to be physiologically relevant during opioid inhibition of Ca2+ channels in DRG neurons.

GABA-Induced Cl− Current in Cultured Embryonic Human Dorsal Root Ganglion Neurons

1999 ◽  
Vol 82 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Alexander Y. Valeyev ◽  
John C. Hackman ◽  
Alice M. Holohean ◽  
Patrick M. Wood ◽  
Jennifer L. Katz ◽  
...  
Keyword(s):  
Dorsal Root Ganglion ◽  
Dorsal Root ◽  
Single Channel ◽  
Dorsal Root Ganglion Neurons ◽  
Hill Coefficient ◽  
Equilibrium Potential ◽  
Single Channels ◽  
Drg Neurons ◽  
Whole Cell ◽  
Ganglion Neurons

γ-Aminobutyric acid (GABA)-activated channels in embryonic (5–8 wk old) human dorsal root ganglion (DRG) neurons in dissociated culture were characterized by whole cell and single-channel techniques. All DRG neurons when held at negative holding membrane potentials displayed inward current to micromolar concentrations of GABA applied by pressure pulses from closely positioned micropipettes. The current was directly proportional to the concentration of GABA (EC50, 111 μM; Hill coefficient, 1.7). DRG neurons also responded to micromolar concentrations of pentobarbital and alphaxalone but not to cis-4-aminocrotonic acid (CACA), glycine, or taurine. Baclofen (100 μM) affected neither the holding currents nor K+ conductance (when patch pipettes were filled with 130 mM KCl) caused by depolarizing pulses. Whole cell GABA-currents were blocked by bicuculline, picrotoxin, and t-butylbicyclophosphorothionate (TBPS; all at 100 μM). The reversal potential of whole cell GABA-currents was close to the theoretical Cl− equilibrium potential, shifting with changes in intracellular Cl− concentration in a manner expected for Cl−-selective channels. The whole cell I-V curve for GABA-induced currents demonstrated slight outward rectification with nearly symmetrical outside and inside Cl− concentrations. Spectral analysis of GABA-induced membrane current fluctuations showed that the kinetic components were best fitted by a triple Lorentzian function. The apparent elementary conductance for GABA-activated Cl− channels determined from the power spectra was 22.6 pS. Single-channel recordings from cell-attached patches with pipettes containing 10 μM GABA indicated that GABA-activated channels have a main and a subconductance level with values of 30 and 19 pS, respectively. Mean open and closed times of the channel were characterized by two or three exponential decay functions, suggesting two or three open channel states and two closed states. Single channels showed a lack of rectification. The actions of GABA on cultured human embryonic DRG neurons are mediated through the activation of GABAA receptors with properties corresponding to those found in the CNS of human and other mammalian species but differing from those of cultured human adult DRG neurons.

scholarly journals Systematic Administration of B Vitamins Alleviates Diabetic Pain and Inhibits Associated Expression of P2X3 and TRPV1 in Dorsal Root Ganglion Neurons and Proinflammatory Cytokines in Spinal Cord in Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Duan-Duan He ◽  
Yu Gao ◽  
Shan Wang ◽  
Zhong Xie ◽  
Xue-Jun Song
Keyword(s):  
Spinal Cord ◽  
Blood Glucose ◽  
Dorsal Root Ganglion ◽  
Proinflammatory Cytokines ◽  
Dorsal Root ◽  
B Vitamins ◽  
Dorsal Root Ganglion Neurons ◽  
Drg Neurons ◽  
B Vitamin ◽  
Ganglion Neurons

Background. Treatment of diabetic neuropathic pain (DNP) continues to be a major challenge, and underlying mechanisms of DNP remain elusive. We investigated treatment effects of B vitamins on DPN- and DNP-associated alterations of neurochemical signaling in the nociceptive dorsal root ganglion (DRG) neurons and the spinal cord in rats. Methods. DNP was produced in male, adult, Sprague Dawley rats by single i.p. streptozotocin (STZ). Western blot analysis and immunohistochemistry were used to analyze protein expressions in DRG and ELISA to measure the proinflammatory cytokines in the spinal cord. Behaviorally expressed DNP was determined by measuring the sensitivity of hindpaw skin to mechanical and thermal stimulation. Results. There were 87.5% (77/88) rats which developed high blood glucose within 1-2 weeks following STZ injection. Of which, 70.13% (n = 54/77) animals exhibited DNP manifested as mechanical allodynia and/or thermal hyperalgesia. Intraperitoneal administration of vitamins B1/B6/B12 (100/100/2 mg/kg, one or multiple doses) significantly attenuated DNP without affecting the blood glucose. Expressions of P2X3 and TRPV1 in CGRP-positive and IB4-positive DRG neurons as well as the interleukin-1β, tumor necrosis factor-α, and nerve growth factor in the lumbar spinal cord were greatly increased in DNP rats. Such DNP-associated neurochemical alterations were also greatly suppressed by the B-vitamin treatment. Conclusions. B-vitamin treatment can greatly suppress chronic DNP and DNP-associated increased activities of P2X3 and TRPV1 in DRG and the spinal proinflammatory cytokines, which may contribute to the pathogenesis of DNP. Systematic administration of B vitamins can be a strategy for DNP management in clinic.

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