• The Korean Journal of Pain
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• v.28 no.3
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• pp.185-192
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• 2015

Background: Neuropathic pain is a global clinical problem; nevertheless, nerve injury treatment methods remain limited. Olanzapine has antinociceptive and anti-nueropathic properties; however, its preventive effects have not been assessed in nerve injury models. Methods: We prepared a partial sciatic nerve ligation (Seltzer model) or sham-operated model in male Sprague-Dawley rats under isoflurane anesthesia. In a pre-treatment study, we administered olanzapine (10 mg/kg) intraperitoneally 1 h before nerve ligation. In post-treatment and dose-dependent studies, we injected 3 different doses of olanzapine intraperitoneally 1 h after nerve ligation. Mechanical allodynia was measured before and 7 days after surgery. Immunohistochemical analysis using anti-Iba-1 antibody was used to assess the effect of olanzapine at the spinal level. Results: In the pre-treatment study, median withdrawal thresholds of the normal saline groups were significantly lower than those of the sham-operated groups; however, those of the olanzapine (10 mg/kg) and sham-operated groups were not different. In the post-treatment and dose-dependent studies, the median withdrawal thresholds of the olanzapine (2.5 mg/kg) and normal saline groups were not different; however, those of the olanzapine (10 and 50 mg/kg) groups were significantly higher than those of the normal saline groups. Olanzapine did not have a significant effect on the density of Iba-1 staining. Conclusions: Olanzapine attenuated mechanical allodynia dose-dependently in the Seltzer model. This anti-allodynic effect of olanzapine was observed even when injected 1 h after nerve ligation. This effect of olanzapine appeared to be unrelated to microglia activation in the ipsilateral dorsal horn of the lumbar spinal cord.

• 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.11 no.1
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• pp.1-6
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• 1998

Background: The role of nitric oxide(NO) in analgesia from opioids is controversial. On the one hand, IV morphine analgesia is enhanced by IV injection of NO synthase inhibitors. On the other hand, IV morphine results in increased release of NO in the spinal cord. There have been no behavioral studies examining the interaction between IV morphine and intrathecal injection of drugs which affect NO synthesis. Method: Rats were prepared with chronic lumbar intrathecal catheters and were tested withdrawal latency on the hot plate after 3~5 days of surgery. Antinociception was determinined in response to a heat stimulus to the hind paw before and after IV injection of morphine, 2.5 mg/kg. Twenty minutes after morphine injection, rats received intrathecal injection of saline or the NO synthase inhibitors, L-NMMA or TRIM, the NO scavenger, PTIO, or the NO synthase substrate, L-Arginine. Intrathecal injections, separated by 15 min, were made in each rats and measurements were obtained every 5 min. Result: Mophine produced a 60~70% maximal antinociceptive response to a heat stimulus in all animals for 60 min in control experiments. Intrathecal injection of idazoxane decreased antinociception of IV morphine. The NO synthase inhibitors and the NO scavenger produced dose-dependent decreases in antinociceptive effect of morphine, whereas saline as a control group and L-Arginine as the NO substrate had no effect on antinociception of morphine. Conclusion: The present study supports the evidences that systemic morphine increase the nitrite in cerebrospinal fluid and dorsal horn. These data suggest that the synthesis of NO in the spinal cord may be important to the analgesic effect of IV morphine and increased NO in spinal cord has different action from the supraspinal NO.

• Korean Journal of Acupuncture
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• v.23 no.3
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• pp.55-71
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• 2006

Objectives : The present study was investigated the effect and pathway of heterotopic electroacupuncture (EA) on pain induced by formalin in rats. Methods : Acupoints in the right forepaws, $HT_7$ and $PC_7$, were stimulated with 3 mA, 2 ms, and 10 Hz before subcutaneously formalin injection (5%, $50{\mu}l$) to the left hind paw. Moreover, it was investigated whether the dorsolateral funiculus (DLF), as known to the descending inhibition, mediates analgesia of the heterotopic EA, and an administration of naltrexone blocks the effect of EA. Results : In the immunohistochemistry of cFos-like protein (cFL), there were inhibitory effects of EA on the increased expression of cFL in the lumbar spinal dorsal horn neurons following formalin injection. Especially, EA inhibited the expression of cFL on the superficial laminae than that on the deep laminae at 1 hr after, but that on the deep laminae than that on the superficial laminae at 2 hr after. Also, EA suppressed the increased expression of nitric oxide (NO) and neuronal nitric oxide synthase (nNOS) in the lumbosacral spinal cord after formalin injection, but not Sham-EA. Suppressed expressions of cFL, NO and nNOS in the spinal cord were eliminated after transection of the ipsilateral DLF at $T_{10}{\sim}T_{11}$ levels. However, pretreatment of naltrexone could not prevent the suppressive expressions of cFL, NO and nNOS at the spinal cord. Conclusions : These results suggest that the analgesia of heterotopic EA may be modulated through the DLF constituting the descending inhibition.

• 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.

• The Journal of Korean Physical Therapy
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• v.14 no.2
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• pp.16-25
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• 2002

Low energy laser irradiation(LELI) therapy in physical therapy is widespread but the mechanisms are not fully understood. The purpose of the present study was to examine the epidermal growth factor(EGF)'s expression within lumbar spinal cord which corresponding with crushed extensor digitorum longus(EDL) of rats after low-power laser irradiation applied. After a crushed injury on the right EDL, low-power laser irradiation was applied by using 2000mW, 2000Hz, 830nm GaAlAs(Gallium-aluminum-arsenide) semiconductor diode laser. The laser treatment was performed with 10 minutes daily for 3days. After EDL crush injury, EGF immunoreactive positive neurons in experimental group were progressively decreased from the first to third days. Especially 1 day subgroup is highly expressed in dorsal horn(Lamina I, II, III) and around of central cannal of spinal cord(Lamina VII). Control group was only expressed slightly at 3 days. This study suggests that LELI stimulate that release and migration of EGF in spinal cord, which distict to wound site, therfore promote wound healing of EDL crush injury.

• International Journal of Oral Biology
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• v.41 no.3
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• pp.141-147
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• 2016

Reactive oxygen species (ROS) and nitrogen species (RNS) are both important signaling molecules involved in pain transmission in the dorsal horn of the spinal cord. Xanthine oxidase (XO) is a well-known enzyme for the generation of superoxide anions ($O_2^{\bullet-}$), while S-nitroso-N-acetyl-DL-penicillamine (SNAP) is a representative nitric oxide (NO) donor. In this study, we used patch clamp recording in spinal slices of rats to investigate the effects of $O_2^{\bullet-}$ and NO on the excitability of substantia gelatinosa (SG) neurons. We also used confocal scanning laser microscopy to measure XO- and SNAP-induced ROS and RNS production in live slices. We observed that the ROS level increased during the perfusion of xanthine and xanthine oxidase (X/XO) compound and SNAP after the loading of 2',7'-dichlorofluorescin diacetate ($H_2DCF-DA$), which is an indicator of intracellular ROS and RNS. Application of ROS donors such as X/XO, ${\beta}-nicotinamide$ adenine dinucleotide phosphate (NADPH), and 3-morpholinosydnomimine (SIN-1) induced a membrane depolarization and inward currents. SNAP, an RNS donor, also induced membrane depolarization and inward currents. X/XO-induced inward currents were significantly decreased by pretreatment with phenyl N-tert-butylnitrone (PBN; nonspecific ROS and RNS scavenger) and manganese(III) tetrakis(4-benzoic acid) porphyrin (MnTBAP; superoxide dismutase mimetics). Nitro-L-arginine methyl ester (NAME; NO scavenger) also slightly decreased X/XO-induced inward currents, suggesting that X/XO-induced responses can be involved in the generation of peroxynitrite ($ONOO^-$). Our data suggest that elevated ROS, especially $O_2^{\bullet-}$, NO and $ONOO^-$, in the spinal cord can increase the excitability of the SG neurons related to pain transmission.

• 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.

• The Korean Journal of Pain
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• v.29 no.3
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• pp.164-171
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• 2016

Background: Nefopam has been known as an inhibitor of the reuptake of monoamines, and the noradrenergic and/or serotonergic system has been focused on as a mechanism of its analgesic action. Here we investigated the role of the spinal dopaminergic neurotransmission in the antinociceptive effect of nefopam administered intravenously or intrathecally. Methods: The effects of intravenously and intrathecally administered nefopam were examined using the rat formalin test. Then we performed a microdialysis study to confirm the change of extracellular dopamine concentration in the spinal dorsal horn by nefopam. To determine whether the changes of dopamine level are associated with the nefopam analgesia, its mechanism was investigated pharmacologically via pretreatment with sulpiride, a dopaminergic D2 receptor antagonist. Results: When nefopam was administered intravenously the flinching responses in phase I of the formalin test were decreased, but not those in phase II of the formalin test were decreased. Intrathecally injected nefopam reduced the flinching responses in both phases of the formalin test in a dose dependent manner. Microdialysis study revealed a significant increase of the level of dopamine in the spinal cord by intrathecally administered nefopam (about 3.8 fold the baseline value) but not by that administered intravenously. The analgesic effects of intrathecally injected nefopam were not affected by pretreatment with sulpiride, and neither were those of the intravenous nefopam. Conclusions: Both the intravenously and intrathecally administered nefopam effectively relieved inflammatory pain in rats. Nefopam may act as an inhibitor of dopamine reuptake when delivered into the spinal cord. However, the analgesic mechanism of nefopam may not involve the dopaminergic transmission at the spinal level.

• Journal of Acupuncture Research
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• v.17 no.2
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• pp.153-168
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• 2000

Introduction : In spite of the use of Bee Venom aqua-acupuncture in the clinics, the scientific evaluation on effects is not enough. Bee Venom aqua-acupuncture is used according to the stimulation of acupuncture point and the chemical effects of Bee Venom. The aims of this study is to investigate the analgegic effects of the Bee Venom aqua-acupuncture, through the change of writhing reflex and the change of c-fos in secondary neurons in the spinal cord. Materials and Methods : Pain animal model was used acetic acid method. The changes of writhing reflex of the mice which were derived pain by injecting acetic acid into the abdomen, after stimulating Bee Venom aqua-acupuncture on Chungwan(CV12) were measured. We used Fos immunohistochemical technique to study the neuronal activity in the spinal cord. Results : 1. Expression of c-fos in superficial dorsal horn(SDH), nucleus proprius(NP) and neck of dorsal hom(N) on 6~9th thoracic spine decreased significantly at $2.5{\times}10-4$g/kg Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 2. The numeral change of Fos-LI neurons on the NP, N, and ventral gray(V) on 6-9th thoracic spine, SDH on 9-11th thoracic spine, and SDH and V on 11~13th thoracic spine decreased significantly at Chungwan(CV12) Bee Venom aqua-acupuncture, compared with saline-acetic acid group. 3. The correlation between the numbers of writhing refleax and Fos-LI neurons in T6-13 segment was statistically statistically significant at Chungwan(CV12) Bee Venom aqua-acupuncture. Conclusion : This study shows that the Bee Venom aqua-acupuncture on Chungwan(CV12) decreases the numbers of Fos-LI neurons. As the analgegic effects of Bee Venom aqua-acupuncture is recognized. Bee Venom aqua-acupuncture treatment is expected for pain modulation. In order to use it in many ways, more researches are needed for the dose and stability of Bee Venom aqua-acupuncture.