Adrenergic signaling mediates mechanical hyperalgesia through activation of P2X3 receptors in primary sensory neurons of rats with chronic pancreatitis

2015 ◽  
Vol 308 (8) ◽  
pp. G710-G719 ◽  
Author(s):  
Shusheng Wang ◽  
Hong-Yan Zhu ◽  
Yi Jin ◽  
Youlang Zhou ◽  
Shufen Hu ◽  
...  
Keyword(s):  
Chronic Pancreatitis ◽  
Receptor Antagonist ◽  
Sensory Neurons ◽  
Adrenergic Receptor ◽  
Receptor Expression ◽  
Mechanical Hyperalgesia ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Adrenergic Signaling ◽  
Pancreatic Pain

The mechanism of pain in chronic pancreatitis (CP) is poorly understood. The aim of this study was designed to investigate roles of norepinephrine (NE) and P2X receptor (P2XR) signaling pathway in the pathogenesis of hyperalgesia in a rat model of CP. CP was induced in male adult rats by intraductal injection of trinitrobenzene sulfonic acid (TNBS). Mechanical hyperalgesia was assessed by referred somatic behaviors to mechanical stimulation of rat abdomen. P2XR-mediated responses of pancreatic dorsal root ganglion (DRG) neurons were measured utilizing calcium imaging and whole cell patch-clamp-recording techniques. Western blot analysis and immunofluorescence were performed to examine protein expression. TNBS injection produced a significant upregulation of P2X3R expression and an increase in ATP-evoked responses of pancreatic DRG neurons. The sensitization of P2X3Rs was reversed by administration of β-adrenergic receptor antagonist propranolol. Incubation of DRG neurons with NE significantly enhanced ATP-induced intracellular calcium signals, which were abolished by propranolol, and partially blocked by protein kinase A inhibitor H-89. Interestingly, TNBS injection led to a significant elevation of NE concentration in DRGs and the pancreas, an upregulation of β2-adrenergic receptor expression in DRGs, and amplification of the NE-induced potentiation of ATP responses. Importantly, pancreatic hyperalgesia was markedly attenuated by administration of purinergic receptor antagonist suramin or A317491 or β2-adrenergic receptor antagonist butoxamine. Sensitization of P2X3Rs, which was likely mediated by adrenergic signaling in primary sensory neurons, contributes to pancreatic pain, thus identifying a potential target for treating pancreatic pain caused by inflammation.

Age-related changes in afferent responses in sensory neurons to mechanical stimulation of osteoblasts in coculture system

2012 ◽  
Vol 302 (5) ◽  
pp. C757-C765 ◽  
Author(s):  
Keiji Asada ◽  
Koji Obata ◽  
Kazuhide Horiguchi ◽  
Miyako Takaki
Keyword(s):  
Receptor Antagonist ◽  
Bone Tissue ◽  
Sensory Neurons ◽  
Satellite Cells ◽  
Mechanical Stimulation ◽  
P2x Receptor ◽  
Bone Homeostasis ◽  
Drg Neurons ◽  
Coculture System ◽  
Sensory Mechanism

Bone homeostasis is regulated by mechanical stimulation (MS). The sensory mechanism of bone tissue for MS remains unknown in the maintenance of bone homeostasis. We aimed to investigate the sensory mechanism from osteoblasts to sensory neurons in a coculture system by MS of osteoblasts. Primary sensory neurons isolated from dorsal root ganglia (DRG) of neonatal, juvenile, and adult mice and osteoblasts isolated from calvaria of neonatal mice were cocultured for 24 h. The responses in DRG neurons elicited by MS of osteoblasts with a glass micropipette were detected by increases in intracellular Ca2+ concentration ([Ca2+]i) with fluo 3-AM. In all developmental stages mice, [Ca2+]i-increasing responses in osteoblasts were promptly elicited by MS. After a short delay, [Ca2+]i-increasing responses were observed in neurites of DRG neurons. The osteoblastic response to second MS was largely attenuated by a stretch-activated Ca2+ channel blocker, gadolinium. The increases of [Ca2+]i in DRG neurons were abolished by a P2 receptor antagonist; suramin, a P2X receptor antagonist, pyridoxal-phosphate-6-azophenyl-2′,4′-disulfonate; and an ATP-hydrolyzing enzyme, apyrase. Satellite cells were found around DRG neurons in cocultured cells of only neonatal and juvenile mice. After satellite cells were removed, excessive abnormal responses to MS of osteoblasts were observed in neonatal neurites with unchanged osteoblast responses. The present study indicated that MS of bone tissue elicited afferent P2X receptor-mediated purinergic transmission to sensory neurons in all stages mice. This transmission is modulated by satellite cells, which may have protective actions on sensory neurons.

scholarly journals Roles for substance P and gastrin-releasing peptide as neurotransmitters released by primary afferent pruriceptors

2013 ◽  
Vol 109 (3) ◽  
pp. 742-748 ◽  
Author(s):  
Tasuku Akiyama ◽  
Mitsutoshi Tominaga ◽  
Auva Davoodi ◽  
Masaki Nagamine ◽  
Kevin Blansit ◽  
...  
Keyword(s):  
Substance P ◽  
Receptor Antagonist ◽  
Sensory Neurons ◽  
Intrathecal Administration ◽  
Primary Sensory Neurons ◽  
Gastrin Releasing Peptide ◽  
Behavioral Studies ◽  
Neurokinin 1 ◽  
Protease Activated Receptor 2 ◽  
Grp Receptor

Recent studies support roles for neurokinin-1 (NK-1) and gastrin-releasing peptide (GRP) receptor-expressing spinal neurons in itch. We presently investigated expression of substance P (SP) and GRP in pruritogen-responsive primary sensory neurons and roles for these neuropeptides in itch signaling. Responses of dorsal root ganglion (DRG) cells to various pruritogens were observed by calcium imaging. DRG cells were then processed for SP, GRP, and isolectin B-4 (IB4; a marker for nonpeptidergic neurons) immunofluorescence. Of pruritogen-responsive DRG cells, 11.8–26.8%, 21.8–40.0%, and 21.4–26.8% were immunopositive for SP, GRP, and IB4, respectively. In behavioral studies, both systemic and intrathecal administration of a NK-1 receptor antagonist significantly attenuated scratching evoked by chloroquine and a protease-activated receptor 2 agonist, SLIGRL, but not histamine, bovine adrenal medulla peptide 8-22 (BAM8-22), or serotonin. Systemic or intrathecal administration of a GRP receptor antagonist attenuated scratching evoked by chloroquine and SLIGRL but not BAM8-22 or histamine. The GRP receptor antagonist enhanced scratching evoked by serotonin. These results indicate that SP and GRP expressed in primary sensory neurons are partially involved as neurotransmitters in histamine-independent itch signaling from the skin to the spinal cord.

Vasoinhibin Suppresses the Neurotrophic Effects of VEGF and NGF in Newborn Rat Primary Sensory Neurons

2017 ◽  
Vol 106 (3) ◽  
pp. 221-233 ◽  
Author(s):  
Ximena Castillo ◽  
Zesergio Melo ◽  
Alfredo Varela-Echavarría ◽  
Elisa Tamariz ◽  
Rodrigo M. Aroña ◽  
...  
Keyword(s):  
Growth Factor ◽  
Neurite Outgrowth ◽  
Sensory Neurons ◽  
Target Cells ◽  
Vascular Endothelial ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Newborn Rat ◽  
Akt Phosphorylation ◽  
Endothelial Growth Factor

Background/Aims: Studies on the biological actions of vasoinhibins have focused mainly on endothelial cells. However, there is incipient knowledge about how vasoinhibins affect the nervous system, even if the target cells and mechanisms of action involved in these effects are unknown. Methods: In order to determine if neurons are direct targets of vasoinhibins, we examined cellular outcomes and the intracellular pathways involved in the neuronal actions of vasoinhibins using newborn rat dorsal root ganglion (DRG) neurons as a model system. Results: Vascular endothelial growth factor (VEGF) or nerve growth factor (NGF) treatment for 48 h resulted in neurite outgrowth stimulation in both DRG cultured explants and isolated primary sensory neurons. Interestingly, a recombinant vasoinhibin containing the first 123 amino acids of human prolactin antagonized the VEGF- and NGF-induced stimulation of neurite outgrowth. Vasoinhibin significantly reduced the density of neurites in DRG explants and obliterated neuritogenesis in isolated DRG neurons in primary culture, supporting a direct neuronal effect of vasoinhibin. In cultures of isolated DRG cells, virtually all β3-tubulin-labeled cells express TrkA, and the majority of these cells also express VEGFR2. Short-term VEGF or NGF treatment of DRG explants resulted in increased ERK1/2 and AKT phosphorylation, whereas incubation of DRG with the combination of either VEGF or NGF together with vasoinhibin resulted in blunted VEGF- or NGF-induced phosphorylation of both ERK1/2 and AKT. Conclusion: Our results show that primary sensory neurons are direct targets of vasoinhibin, and suggest that vasoinhibin inhibition of neurite outgrowth involves the disruption of ERK and AKT phosphorylation cascades.

scholarly journals Bilateral Neuropathy of Primary Sensory Neurons by the Chronic Compression of Multiple Unilateral DRGs

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Ya-Bin Xie ◽  
Huan Zhao ◽  
Ying Wang ◽  
Kai Song ◽  
Ming Zhang ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Spontaneous Pain ◽  
Activating Transcription Factor 3 ◽  
Thermal Preference ◽  
Primary Sensory Neurons ◽  
Nerve Root Compression ◽  
Drg Neurons ◽  
Cold Allodynia ◽  
Activating Transcription Factor ◽  
Intervertebral Foramina

To mimic multilevel nerve root compression and intervertebral foramina stenosis in human, we established a new animal model of the chronic compression of unilateral multiple lumbar DRGs (mCCD) in the rat. A higher occurrence of signs of spontaneous pain behaviors, such as wet-dog shaking and spontaneous hind paw shrinking behaviors, was firstly observed from day 1 onward. In the meantime, the unilateral mCCD rat exhibited significant bilateral hind paw mechanical and cold allodynia and hyperalgesia, as well as a thermal preference to 30°C plate between 30 and 35°C. The expression of activating transcription factor 3 (ATF3) was significantly increased in the ipsilateral and contralateral all-sized DRG neurons after the mCCD. And the expression of CGRP was significantly increased in the ipsilateral and contralateral large- and medium-sized DRG neurons. ATF3 and CGRP expressions correlated to evoked pain hypersensitivities such as mechanical and cold allodynia on postoperative day 1. The results suggested that bilateral neuropathy of primary sensory neurons might contribute to bilateral hypersensitivity in the mCCD rat.

A-Type Voltage-Gated K+ Currents Influence Firing Properties of Isolectin B4-Positive But Not Isolectin B4-Negative Primary Sensory Neurons

2005 ◽  
Vol 93 (6) ◽  
pp. 3401-3409 ◽  
Author(s):  
Amaresh Vydyanathan ◽  
Zi-Zhen Wu ◽  
Shao-Rui Chen ◽  
Hui-Lin Pan
Keyword(s):  
Sensory Neurons ◽  
Action Potentials ◽  
Neuronal Excitability ◽  
Cell Voltage ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Voltage Gated ◽  
The Difference ◽  
Firing Properties ◽  
Isolectin B4

Voltage-gated K+ channels (Kv) in primary sensory neurons are important for regulation of neuronal excitability. The dorsal root ganglion (DRG) neurons are heterogeneous, and the types of native Kv currents in different groups of nociceptive DRG neurons are not fully known. In this study, we determined the difference in the A-type Kv current and its influence on the firing properties between isolectin B4 (IB4)-positive and -negative DRG neurons. Whole cell voltage- and current-clamp recordings were performed on acutely dissociated small DRG neurons of rats. The total Kv current density was significantly higher in IB4-positive than that in IB4-negative neurons. Also, 4-aminopyridine (4-AP) produced a significantly greater reduction in Kv currents in IB4-positive than in IB4-negative neurons. In contrast, IB4-negative neurons exhibited a larger proportion of tetraethylammonium-sensitive Kv currents. Furthermore, IB4-positive neurons showed a longer latency of firing and required a significantly larger amount of current injection to evoke action potentials. 4-AP significantly decreased the latency of firing and increased the firing frequency in IB4-positive but not in IB4-negative neurons. Additionally, IB4-positive neurons are immunoreactive to Kv1.4 but not to Kv1.1 and Kv1.2 subunits. Collectively, this study provides new information that 4-AP–sensitive A-type Kv currents are mainly present in IB4-positive DRG neurons and preferentially dampen the initiation of action potentials of this subpopulation of nociceptors. The difference in the density of A-type Kv currents contributes to the distinct electrophysiological properties of IB4-positive and -negative DRG neurons.

scholarly journals Serum From Diabetic BB/W Rats Enhances Calcium Currents in Primary Sensory Neurons

1998 ◽  
Vol 80 (3) ◽  
pp. 1236-1244 ◽  
Author(s):  
Helen Ristic ◽  
Shanthi Srinivasan ◽  
Karen E. Hall ◽  
Anders A. F. Sima ◽  
John W. Wiley
Keyword(s):  
Calcium Channel ◽  
G Protein ◽  
Sensory Neurons ◽  
Calcium Influx ◽  
Surface Membrane ◽  
Calcium Currents ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Patch Clamp Technique ◽  
Inhibitory G Protein

Ristic, Helen, Shanthi Srinivasan, Karen E. Hall, Anders A. F. Sima, and John W. Wiley. Serum from diabetic BB/W rats enhances calcium currents in primary sensory neurons. J. Neurophysiol. 80: 1236–1244, 1998. We examined the hypothesis that exposure of nondiabetic rat dorsal root ganglion (DRG) neurons to sera from diabetic BB/W rats would produce an increase in calcium currents associated with impaired regulation of the inhibitory G protein–calcium channel complex. Acutely dissociated rat DRGs were incubated for 18–24 h in medium supplemented with sera (10% vol/vol) from either diabetic rats with neuropathy or age-matched, nondiabetic controls. Exposure of DRG neurons to sera from diabetic BB/W rats resulted in a surface membrane immunofluorescence pattern when treated with an anti-rat light-chain antibody that was not observed in neurons exposed to control sera. Calcium current density ( I DCa) was assessed with the use of the whole cell variation of the patch-clamp technique. I DCa in neurons exposed to diabetic sera was significantly increased compared with neurons exposed to control sera. Guanine nucleotide-binding (G) protein regulation of calcium channel function was examined with the use of a two-pulse “facilitation” or I DCa enhancement protocol in the presence of activators [guanosine 5′-O-(3-thiotriphosphate) (GTPγS)] or antagonists [guanosine 5′-O-(2-thiodiphosphate) (GDPβS) and pertussis toxin (PTX)] of G protein function. Facilitation was significantly decreased in neurons exposed to diabetic sera. Intracellular diffusion of neurons with GDPβs blocked facilitation, whereas dialysis with GTPγs increased facilitation to a similar magnitude in neurons exposed to either diabetic or control sera. Treatment with PTX resulted in a significant increase in I DCa and ∼50% decrease in facilitation in neurons treated with control sera but no significant changes in neurons exposed to diabetic sera. We conclude that serum from diabetic BB/W rats with neuropathy contains an autoimmune immunoglobulin that impairs regulation of the inhibitory G protein–calcium channel complex, resulting in enhanced calcium influx. Regulation of the inhibitory G protein–calcium channel complex involves PTX-sensitive and -insensitive G proteins.

scholarly journals Histone methyltransferase G9a diminishes expression of cannabinoid CB1 receptors in primary sensory neurons in neuropathic pain

2020 ◽  
Vol 295 (11) ◽  
pp. 3553-3562 ◽  
Author(s):  
Yi Luo ◽  
Jixiang Zhang ◽  
Lin Chen ◽  
Shao-Rui Chen ◽  
Hong Chen ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Nerve Injury ◽  
Sensory Neurons ◽  
Analgesic Effect ◽  
Spinal Cord Dorsal Horn ◽  
Epigenetic Mechanism ◽  
Mrna Levels ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Histone 3

Type 1 cannabinoid receptors (CB1Rs) are expressed in the dorsal root ganglion (DRG) and contribute to the analgesic effect of cannabinoids. However, the epigenetic mechanism regulating the expression of CB1Rs in neuropathic pain is unknown. G9a (encoded by the Ehmt2 gene), a histone 3 at lysine 9 methyltransferase, is a key chromatin regulator responsible for gene silencing. In this study, we determined G9a's role in regulating CB1R expression in the DRG and in CB1R-mediated analgesic effects in an animal model of neuropathic pain. We show that nerve injury profoundly reduced mRNA levels of CB1Rs but increased the expression of CB2 receptors in the rat DRG. ChIP results indicated increased enrichment of histone 3 at lysine 9 dimethylation, a G9a-catalyzed repressive histone mark, at the promoter regions of the CB1R genes. G9a inhibition in nerve-injured rats not only up-regulated the CB1R expression level in the DRG but also potentiated the analgesic effect of a CB1R agonist on nerve injury-induced pain hypersensitivity. Furthermore, in mice lacking Ehmt2 in DRG neurons, nerve injury failed to reduce CB1R expression in the DRG and to decrease the analgesic effect of the CB1R agonist. Moreover, nerve injury diminished the inhibitory effect of the CB1R agonist on synaptic glutamate release from primary afferent nerves to spinal cord dorsal horn neurons in WT mice but not in mice lacking Ehmt2 in DRG neurons. Our findings reveal that nerve injury diminishes the analgesic effect of CB1R agonists through G9a-mediated CB1R down-regulation in primary sensory neurons.

Expression of Galanin in Rat Primary Sensory Afferents After Moxibustion to the Skin

1992 ◽  
Vol 20 (02) ◽  
pp. 103-114 ◽  
Author(s):  
Hitoshi Kashiba ◽  
Ayahiko Nishigori ◽  
Yoshihiro Ueda
Keyword(s):  
Substance P ◽  
Dorsal Root Ganglion ◽  
Sensory Neurons ◽  
Untreated Control ◽  
Dorsal Root ◽  
Primary Sensory Neurons ◽  
Drg Neurons ◽  
Sensory Afferents ◽  
Retrograde Tracer ◽  
Control Skin

We examined the effects of moxibustion on primary sensory neurons in the skin of rats using immunocytochemistry combined with a fluorescent retrograde tracer dye, fluoro gold (FG). Galanin-like immunoreactive (IR) fibers were often observed in the dermis of treated skin at 18 hours after moxibustion, while such fibers were rarely detected in untreated (control) skin. Moreover, most of galanin-IR fibers also displayed substance P(SP)-like immunoreactivity. About 20-30% of the dorsal root ganglion (DRG) neurons labeled when FG was injected intradermally into the moxibustion-treated skin showed galanin-like immunoreactivity, while the proportion of FG-labeled neurons with such immunoreactivity was < 10% in control DRGs. These results show that moxibustion induced galanin expression by primary sensory neurons containing SP. The possible functions of this peptide are discussed in relation to the effects of moxibustion.

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