• The Journal of Korean Physical Therapy
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• v.22 no.3
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• pp.93-98
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• 2010

Purpose: To investigate temporal changes in IL-1${\beta}$ mRNA expression in spinal dorsal horn (DH) and dorsal root ganglion (DRG) in a rat lumbar disc herniation (LDH) model. Methods: Autologous nucleus pulposus, harvested from the tail disc between the second and third coccygeal vertebrae (Co2-3), was implanted next to the left L5 nerve root just proximal to the DRG after partial laminectomy. IL-1${\beta}$ mRNA expression was investigated in DRG and DH in our LDH model. Real-time PCR assays were done using a 7500 Real Time PCR system (Applied Biosystems, USA). Results: Expression of IL-1${\beta}$ in DRG and DH was observed for 30 days postoperatively. Expression of IL-1${\beta}$ mRNA in the ipsilateral DRG of the LDH group gradually increased from 5 to 30 days after surgery. The amount of IL-1${\beta}$ in the contralateral DRG peaked 10 days after surgery and then gradually decreased. However, there was no difference in IL-1${\beta}$ mRNA expression in spinal DH between the LDH group and the sham-operated group. Conclusion: Long-term expression of IL-1${\beta}$ in the LDH model may worsen the chronic pain state. Future studies on inhibition of IL-1${\beta}$ expression in the LDH model will be needed to develop selective treatment strategies for patients with LDH.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.6
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• pp.553-558
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• 2013

Spinal dorsal horn nociceptive neurons have been shown to undergo long-term synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD). Here, we focused on the spinothalamic tract (STT) neurons that are the main nociceptive neurons projecting from the spinal cord to the thalamus. Optical technique using fluorescent dye has made it possible to identify the STT neurons in the spinal cord. Evoked fast mono-synaptic, excitatory postsynaptic currents (eEPSCs) were measured in the STT neurons. Time-based tetanic stimulation (TBS) was employed to induce long-term potentiation (LTP) in the STT neurons. Coincident stimulation of both pre- and postsynaptic neurons using TBS showed immediate and persistent increase in AMPA receptor-mediated EPSCs. LTP can also be induced by postsynaptic spiking together with pharmacological stimulation using chemical NMDA. TBS-induced LTP observed in STT neurons was blocked by internal BAPTA, or $Ni^{2+}$, a T-type VOCC blocker. However, LTP was intact in the presence of L-type VOCC blocker. These results suggest that long-term plastic change of STT neurons requires NMDA receptor activation and postsynaptic calcium but is differentially sensitive to T-type VOCCs.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.1
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• pp.117-123
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• 2002

To investigate the antiinflammatory and analgesic effects of Sophorae radix extracts administered to the arthritic rat model, immunohistochemical stains for CGRP in the L4, L5 and L6 spinal cord and ganglia were done, and paw swelling thickness were measured. Complete Freund,s Adjuvant(CFA) were injected to subcutaneous tissue of left foot paw of rats to induce arthritis. Sophorae radix extracts was administered immediately after CFA injection for 10 days. The spinal cord and ganglia were frozen sectioned(30㎛). These sections were stained by CGRP immunohistochemical staining method, and observed with light microscope. The results were as follows : 1. The change of paw swelling thickness of experimental group decreased from 4 day to 10day after CFA injection compared to control group. 2. The change of differential leukocytes counts of experimental group increased the ratio of lymphocytes. and decreased the ratio of neutrophils compared to control group. 3. The change of CGRP immunoreactive nerve fiber of dorsal horn of experimental group was dense stained compared to control group. 4. The number of CGRP immunoreactive neurons of L4 and L5 spinal cord of experimental group was less than in those control group. These results suggested that Sophorae radix extracts reduces the number of CGRP immunoreactive neurons and nerve fibers of spinal cord and ganglia, and decrease paw swelling thickness in arthritic rat model, which may be closely related to analgesic and antiinflammatory effects of Sophorae radix.

• The Korean Journal of Pain
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• v.14 no.1
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• pp.1-6
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• 2001

Background: Subcutaneous injection of 5% formalin into the hind paw of the rat produces a biphasic nociceptive response. The second phase depends on changes in the dorsal horn cell function that occur shortly after an initial C-fiber discharge, spinal sensitization, or windup phenomenon. This study was performed to investigate the role of glutamate during spinal sensitization. Methods: Sprague-Dawley rats weighing 200 to 250 g were used for this study. Under light anesthesia (0.5% isoflurane) the rats were segregated in a specially designed cage and $50{\mu}l$ 0.5% formalin was injected subcutaneously in the foot dorsum of right hindlimb. Forty minutes after the formalin injection, the rat was quickly decapitated and spinal cord was removed. The spinal segments at the level of L3 (largest area) was collected and stored in a deep freezer ($-70^{\circ}C$). The mRNA gene expression of N-methyl-D-aspartate receptor (NMDAR) and the metabotropic glutamate receptor subtype 5 (mGluR5) were determined by the polymerase chain reaction. Results: The number of flinches was $19.8{\pm}2.3/min$. at one minute after formalin injection and decreased to zero after then. The second peak appeared at 35 and 40 minutes after formalin injection. The values were $17.8{\pm}2.2$ and $17.2{\pm}3.0/min$. The mRNA gene expressions of NMDAR and mGluR5 were increased by $459.0{\pm}46.8%$ (P < 0.01) and $111.1{\pm}4.8%$ (P > 0.05) respectively at 40 minutes after formalin injection. The increased rate of NMDAR was significantly higher than that of mGluR5 (P < 0.01). Conclusions: From these results it suggested that NMDAR partly contributed to the mechanism of central sensitization after the formalin test but mGluR5 did not.

• Korean Journal of Acupuncture
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• v.36 no.4
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• pp.264-273
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• 2019

Objectives : Microglia play a crucial role in electroacupuncture (EA) analgesia on neuropathic pain. The role of chemokines in producing analgesic effects of EA, however, is largely unknown. In the present study, we investigated the role of chemokines in producing analgesic effects of EA in the neuropathic pain model. Methods : Sprague-Dawley rats were randomly assigned into three groups (anesthetized group (ANE), non-acupoint EA group (NAP), and ST36 - GB34 EA group (ACU)). Neuropathic pain was induced by tight ligation of L5 spinal nerve. Mechanical and thermal hypersensitivity of hind paw was tested. Western blot tests and immunofluorescence assay for C-C motif chemokine ligand 2 (CCL2) levels and microglia activation were performed on spinal cord L5/6. EA was treated once daily from the 3rd day after surgery for 5 days. Results : EA treatments applied to ST36 and GB34 significantly reduced both mechanical and thermal hypersensitivity after two and three times of treatment, respectively. While CCL2 expression significantly increased in neuropathic rats, it was significantly reduced in the ACU. In addition, co-localization of CCL2 and activated microglia significantly decreased in the ACU compared to those of ANE and NAP in the spinal cord L5/L6 dorsal horn. Conclusions : The present results suggest that EA applied to ST36 and GB34 modulates the reduction of CCL2 release from the injured neurons and consequently decreases microglia activation in the spinal cord. Regulation of chemokine induced spinal activation of microglia plays a key role in analgesic effects of EA in the rat model of neuropathic pain.

• International Journal of Oral Biology
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• v.40 no.2
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• pp.71-77
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• 2015

The activation of glial cells in the spinal cord has been contribute to the initiation and maintenance of pain facilitation induced by peripheral inflammation and nerve injury. The present study investigated effects of botulinum toxin type A (BoNT-A), injected subcutaneously or intracisternally, on the expression of microglia and astrocytes in rats. Complete Freund's Adjuvant (CFA)-induced inflammation was employed as an orofacial chronic inflammatory pain model. A subcutaneous injection of $40{\mu}L$ CFA into the vibrissa pad was performed under 3% isoflurane anesthesia in SD rats. Immunohistochemical analysis for changes in Iba1 (a microglia marker) and GFAP (an astrocyte marker), were performed 5 days after CFA injection. Subcutaneous injection of CFA produced increases in Iba1 and GFAP expression, in the ipsilateral superficial lamia I and II in the medullary dorsal horn of rats. Subcutaneous treatment with BoNT-A attenuated the up-regulation of Iba1 and GFAP expressions induced by CFA injection. Moreover, intracisternal injection of BoNT-A also attenuated the up-regulated Iba1 and GFAP expressions. These results suggest that the anti-nociceptive action of BoNT-A is mediated by modulation activation of glial cells, including microglia and astrocyte.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.17-28
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• 1998

The present study was designed to investigate the effect of different stimulation-duration of high frequency electroacupuncturet(EA) treatment on the neuronal activities in the spinal cord and brainstem using Fos immunohistochemical technique. Three different stimulus-duration was used in this experiment : 30minutes, 1 hour and 2 hours. The summerized results were summerized as follow : 1. The number of Fos expression was significantly increased in the spinal cord dorsal horn depending upon the increase of stimulus-duration (P<0.05). Otherwise, there was no significant difference between 30 minutes EA treated group and anesthetic control. 2. High frequency EA biphasic stimulation significantly enhanced the Fos expression in the DR, middle and rostral portion of PAG LD, and caudal PAG LV after 1 hour and 2 hours treatment. The number of Fos immunoreactive neuron in the brainstem was increased accorcting to the length of stimulus-duration. Those results indicate that at least 1 hour EA treatment was necessary to increase the neuronal activities in the spinal cord and brainstem. Those basic data from this study can be applied to establish the effective treatment of EA for pain control in the clinical field.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.4
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• pp.805-817
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• 2009

This study was to investigate central localization of neurons projecting to the urinary bladder and urinary bladder-related acupoints(Wijung, $BL_{40}$) and neurons of immunoreactive to hormones and hormone receptors regulating urinary bladder function by using peudorabies virus(PRV). In this experiment, Bartha's strain of pseudorabies virus was used in rats to trace central localization of urinary bladder-related neurons and urinary bladder-related acupoints($BL_{40}$) which can regulate urinary system. PRV was injected into the urinary bladder and acupoints($BL_{40}$) related urinary system. After six days survival of rats, mainly common labeled neurons projecting to the urinary bladder and urinary bladder-related acupoints were identified in spinal cord, medulla, pons and diencephalon by PRV immunohistochemical staining method. First-order PRV labeled neurons projecting to urinary bladder and urinary bladder-related acupoints were found in the cervical, thoracic, lumbar and sacral spinal cord. Commonly labeled preganglionic neurons were labeled in the lumbosacral spinal cord and thoracic spinal cord. They were found in the lateral horn area(sacral parasympathetic nucleus and intermediolateral nucleus), lamina V-X, intermediomedial nucleus and dorsal column area. The area of sensory neurons projecting to urinary bladder and Wijung($BL_{40}$) was L5-S2 spinal ganglia and T12-L1 spinal ganglia, respectively. In the brainstem, the neurons were labeled most evidently and consistently in the nucleus of tractus solitarius, area postrema, dorsal motor nucleus of vagus nerve, reticular nucleus, raphe nuclei(obscurus, magnus and pallidus), C3 adrenalin cells, parapyramidal area(lateral paragigantocellular nucleus), locus coeruleus, subcoeruleus nucleus, A5 cell group, Barrington's nucleus and periaqueductal gray matter. In the diencephalon, PRV labeled neurons were marked mostly in the paraventricular nucleus and a few ones were in the lateral hypothalamic nucleus, posterior hypothalamic nucleus, ventromedial hypothalamic nucleus, arcuate nucleus, median eminence, perifornical nucleus, periventricular nucleus and suprachiasmatic nucleus. In cerebral cortex, PRV labeled neurons were marked mostly in the frontal cortex, 1,2 area, hind limb area, agranular insular cortex. Immunoreactive neurons to Corticotropin releasiing factor(CRF), Corticotropin releasiing factor-receptor(CRF-R), c-fos and serotonin were a part of labeled areas among the virus-labeled neurons of urinary bladder and Wijung($BL_{40}$). The commonly labeled areas were nucleus tractus solitarius, area postrema, reticular nucleus, raphe nuclei(obscurus, magnus and pallidus), locus coeruleus, A5 cell group, Barrington,s nucleus, arcuate nucleus, paraventricular nucleus, frontal cortex 1, 2 area, hind limb, and perirhinal(agranular insular) cortex. These results suggest that overlapped CNS locations are related with autonomic nuclei which regulate the functions of urinary bladder-relate organs and it was revealed by tracing PRV labeled neurons projecting urinary bladder and urinary bladder-related acupoints. These commonly labeled areas often overlap with the neurons connected with hormones and hormone receptors related to urination.

• The Korean Journal of Pain
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• v.7 no.2
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• pp.282-286
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• 1994

The central antihypertensive agent clonidine is an ${\alpha}_2$-adrenergic agonist that possesses pain-relieving properties. It has been administered epidurally in the treatment of cancer pain and for postoperative analgesia. 1) Case 1, 62-year-old woman who suffered from neurogenic pain syndrome due to metastatic squamous cell carcinoma of spinal canal was treated. 2) Case 2, 51-year-old woman undergoing lower abdominal surgery, epidurally administered morphine did not produced postoperative analgesia. In these cases, continuous epidural administeration of clonidine (200ug/day) and 0.3% bupivacaine(12 ml/day) produce high quality pain relief. These results suggest that antinociceptive effect of epidural clonidine is assumed to result from activation of ${\alpha}_2$-adrenergic receptors in the dorsal horn of the spinal cord.

• International Journal of Oral Biology
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• v.42 no.2
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• pp.55-61
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• 2017

Recent studies indicate that mitochondria are an important source of reactive oxygen species (ROS) in the spinal dorsal horn. In our previous study, application of malate, a mitochondrial electron transport complex I substrate, induced a membrane depolarization, which was inhibited by pretreatment with ROS scavengers. In the present study, we used patch clamp recording in the substantia geletinosa (SG) neurons of spinal slices, to investigate the cellular mechanism of mitochondrial ROS on neuronal excitability. DNQX (an AMPA receptor antagonist) and AP5 (an NMDA receptor antagonist) decreased the malate-induced depolarization. In an external calcium free solution and addition of tetrodotoxin (TTX) for blockade of synaptic transmission, the malate-induced depolarization remained unchanged. In the presence of DNQX, AP5 and AP3 (a group I metabotropic glutamate receptor (mGluR) antagonist), glutamate depolarized the membrane potential, which was suppressed by PBN. However, oligomycin (a mitochondrial ATP synthase inhibitor) or PPADS (a P2 receptor inhibitor) did not affect the substrates-induced depolarization. These results suggest that mitochondrial substrate-induced ROS in SG neuron directly acts on the postsynaptic neuron, therefore increasing the ion influx via glutamate receptors.