• Restorative Dentistry and Endodontics
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• v.26 no.5
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• pp.436-442
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• 2001

Neuropeptide such as calcitonin gene-related peptide and substance P may mediate neurogenic inflammation, but little is known about the regulation of neuropeptide release from rat spinal cord. Eugenol has been reported to reduce odontogenic pain and is known to have a structure similar to capsaicin, a potent stimulant of certain nociceptors. This study was done to examine the effect of capsaicin and eugenol on immunoreactive calcitonin gene-related peptide (iCGRP) release from rat spinal cord and whether eugenol regulates capsaicin-sensitive release of iCCRP or it evokes capsaicin-sensitive release of iCGRP. The dor-sal half of rat lumbar spinal cord was chopped into 200$\mu$m slices. They were superfused (500$\mu$l/min) in vitro with an oxygenated Kreb's buffer. The EC$_{50}$ of capsaicin on iCGRP release was measured. Eugenol (600$\mu$M and 1.2mM) and vehicle (0.02% 2-hydroxyl-$\beta$-cyclodextrin) were administered prior to stimulation of rat lumbar spinal cord with capsaicin. The amount of iCGRP release from rat lumbar spinal cord was measured by radioimmunoassay. The results were as follows : 1. iCGRP release from rat lumbar spinal cord was dependent on concentration of capsaicin. The EC$_{50}$ of capsaicin on iCGRP release was 3$\mu$M. 2. In the vehicle treated group, capsaicin (3$\mu$M) evoked a 14-fold increase over basal iCGRP level. 3. Administration of 600$\mu$M and 1.2mM eugenol evoked a 2.2-fold increase and a 2.3-fold increase over basal iCGRP level respectively. 4. Administration of 600$\mu$M and 1.2mM eugenol increased capsaicin evoked release of iCGRP by more than 50%. These results indicate that eugenol evoke CGRP release from central nervous system and potentiate the pain-inducing action of capsaicin on it.

• Animal cells and systems
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• v.4 no.4
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• pp.353-359
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• 2000

Location of the neurons in the lateral reticular nucleus projecting to dorsal horn of the cervical, thoracic, or lumbar spinal cord was investigated in the rat using the technique of retrograde transport of horseradish peroxidase. The projection was bilateral with ipsilateral predominance. Neurons projecting to the cervical spinal cord were located near the medial, dorsal, and lateral perimeter of the magnocellular division of the lateral reticular nucleus, whereas cells projecting to the thoracic and lumbar spinal cord were localized in the medial and dorsal boundaries of the magnocellular division. The labeled neurons were distinctly multipolar in shape and measured approximately 10-15 $\mu m$ in their greatest transverse diameter. A few neurons were also observed in the subtrigeminal nucleus, whereas few cells were in the parbocellular division. These observations provide an anatomical substrate for the functional implication of the lateral reticular nucleus in the regulation of spinal nociceptive transmission and vascular hemodynamics via the descending pathway into the spinal cord.

• Journal of Magnetics
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• v.16 no.3
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• pp.253-258
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• 2011

The purpose of this study was to identify the effect of pulsed electromagnetic fields on the expression of neurotrophic factors after spinal cord injury. Sprague-Dawley male rats were given a spinal cord hemisection and randomly divided into 2 groups, the control and experimental groups. The experimental group was administered a fifteen minutes session of pulsed electromagnetic field once a day, five days a week. In order to observe the effect of these pulsed electromagnetic fields, this study observed the BDNF expression in the rat's lumbar spinal cord and the H&E staining in the gastrocnemius at 3, 7, 14, 21 days group after spinal cord hemisection. The results of this showed that the immunoreactivity of the BDNF in the rat's spinal cord gradually increased in each group. At 21 days, there is a significant difference between the control and experimental groups. The morphological shape of the gastrocnemius was gradually changed from 3days to 21days, and the gastrocnemius at 21 days was significantly degraded. However, the experimental group showed a slightly more organized gastrocnemius than the control group at 21days. The Results of this study suggest that pulsed electromagnetic field application decreases the degeneration of a rat's gastrocnemius morphology, and increases the immunoreactivity of the BDNF in the rat's spinal cord after spinal cord hemisection.

• Physical Therapy Korea
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• v.14 no.2
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• pp.11-20
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• 2007

The development of neonatal neuromuscular system is accomplished by the functional interaction between the spinal neurons and its target cells, skeletal muscle cells, and the intrinsic and extrinsic factors affecting this process. The aim of this study was to identify the effect of suspension unloading (SU) and neuromuscular electrical stimulation (NMES) upon the development of the neonatal spinal cord. For this study, the neonatal rats were randomly divided into three groups: a control group, an experimental group I, and an experimental group II. The SU for experimental group I and II was applied from postnatal day (PD) 5 to PD 30, and the NMES for experimental group II was applied from PD 16 to PD 30 using NMES that gave isometric contraction with 10 Hz for 30 minutes twice a day. In order to observe the effect of SU and NMES, this study observed neutrophin-3 (NT-3) and microtubule associated protein 2 (MAP2) immunoreactivity in the lumbar spinal cord (L4-5) at the PD 15 and PD 30. The results are as follows. At PD 15, lumbar spinal cord of experimental group I and II had significantly lower NT-3 and MAP2 immunoreactivity than control group. It proved that a microgravity condition restricted the spinal development. At PD 30, lumbar spinal cord of control group and experimental group II had significantly higher NT-3 and MAP2 immunoreactivity than experimental group I. It proved that the NMES facilitated the spinal development by spinal cord-skeletal muscle interaction. These results suggest that weight bearing during the neonatal developmental period is essential for the development of neuromuscular development. Also, the NMES on its target skeletal muscle can encourage the development of the spinal cord system with a full supplementation of the effect of weight bearing, which is an essential factor in neonatal developmental process.

• Journal of Chest Surgery
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• v.45 no.2
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• pp.73-79
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• 2012

Background: Aortic cross clamping is associated with spinal cord ischemia. This study used a rat spinal cord ischemia model to investigate the effect of distal aortic pressure on spinal cord perfusion. Materials and Methods: Male Sprague-Dawley rats (n=12) were divided into three groups. In group A (n=4), the aorta was not occluded. In groups B (n=4) and C (n=4), the aorta was occluded. In group B the distal aortic pressures dropped to around 20 mmHg. In group C, the distal aortic pressure was decreased to near zero. The carotid artery and tail artery were cannulated to monitor the proximal aortic pressure and the distal aortic pressure. Fluorescent microspheres were used to measure the regional blood flow in the spinal cord. Results: After aortic occlusion, blood flow to the cervical spinal cord showed no significant difference among the three groups. In groups B and C, the thoracic and lumbar spinal cord and renal blood flow decreased. No microspheres were detected in the thoracic and lumbar spinal cord of group C. Conclusion: The spinal cord blood flow is dependent on the distal aortic pressure after thoracic aortic occlusion.

• Journal of Korean Neurosurgical Society
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• v.61 no.4
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• pp.434-440
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• 2018

Objective : The purpose of this study was to find an optimal delivery route for clinical trials of intrathecal cell therapy for spinal cord injury in preclinical stage. Methods : We compared in vivo distribution of Cy5.5 fluorescent dye in the spinal cord region at various time points utilizing in vivo optical imaging techniques, which was injected into the lateral ventricle (LV) or cisterna magna (CM) of rats. Results : Although CM locates nearer to the spinal cord than the LV, significantly higher signal of Cy5.5 was detected in the thoracic and lumbar spinal cord region at all time points tested when Cy5.5 was injected into the LV. In the LV injection Cy5.5 signal in the thoracic and lumbar spinal cord was observed within 12 hours after injection, which was maintained until 72 hours after injection. In contrast, Cy5.5 signal was concentrated at the injection site in the CM injection at all time points. Conclusion : These data suggested that the LV might be suitable for preclinical injection route of therapeutics targeting the spinal cord to test their treatment efficacy and biosafety for spinal cord diseases in small animal models.

• The Korean Journal of Physiology
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• v.28 no.2
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• pp.113-122
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• 1994

The present study was carried out to characterize the functional properties of spinomesencephalic tract (SMT) neurons in the lumbar spinal cord of urethane anesthetized rats. Extracellular single unit recordings were made from neurons antidromically activated by stimulation of the midbrain area, including the deep layers of superior colliculus, periaqueductal gray and midbrain reticular formation. Recording sites were located in laminae I-VII of spinal cord segments of L2-L5. Receptive field properties and responses to calibrated mechanical stimulation were studied in 78 SMT cells. Mean conduction velocity of SMT neurons was $19.1{\pm}1.04\;m/sec$. SMT units were classified according to their response profiles into four groups: wide dynamic range (58%), deep/tap (23%), high threshold (9%) and low threshold (3%). A simple excitatory receptive field was found for most SMT neurons recorded in superficial dorsal horn (SDH). Large complex inhibitory and/or excitatory receptive fields were found for cells in lateral reticulated area which usually showed long after-discharge. Most of SMT cells received inputs from $A{\delta}$ and C afferent fiber types. These results suggest that sensory neurons in the rat SMT may have different functional roles according to their location in the spinal cord in integrating and processing sensory inputs including noxious mechanical stimuli.

• Journal of Korean Neurosurgical Society
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• v.49 no.2
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• pp.83-91
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• 2011

Objective : Minocycline, a second-generation tetracycline-class antibiotic, has been well established to exert a neuroprotective effect in animal models and neurodegenerative disease through the inhibition of microglia. Here, we investigated the effects of minocycline on motor recovery and neuropathic pain in a rat model of spinal cord injury. Methods : To simulate spinal cord injury, the rats' spinal cords were hemisected at the 10th thoracic level (T10). Minocycline was injected intraperitoneally, and was administered 30 minutes prior surgery and every second postoperative day until sacrifice 28 days after surgery. Motor recovery was assessed via the Basso-Beattie-Bresnahan test Mechanical hyperalgesia was measured throughout the 28-day post -operative course via the von Frey test Microglial and astrocyte activation was assessed by immunohistochemical staining for ionized calcium binding adaptor molecule 1 (lba1) and glial fibrillary acidic protein (GFAP) at two sites: at the level of hemisection and at the 5th lumbar level (L5). Results : In rats, spinal cord hemisection reduced locomotor function and induced a mechanical hyperalgesia of the ipsilateral hind limb. The expression of lba1 and GFAP was also increased in the dorsal and ventral horns of the spinal cord at the site of hemisection and at the L5 level. Intraperitoneal injection of minocycline facilitated overall motor recovery and attenuated mechanical hyperalgesia. The expression of lba1 and GFAP in the spinal cord was also reduced in rats treated with minocycline. Conclusion : By inhibiting microglia and astrocyte activation, minocycline may facilitate motor recovery and attenuate mechanical hyperalgesia in individuals with spinal cord injuries.

• Korean Journal of Acupuncture
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• v.34 no.1
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• pp.1-7
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• 2017

Objectives : The purpose of this study was to evaluate effects of taping therapy on recovery of behavioral symptoms and neural excitability of the lumbar spinal cord in rat model for ankle sprain. Methods : Adult Sprague-Dawley rats was used and divided into 3 experimental groups: normal group(n=6), ankle sprain(n=6), and ankle sprain with taping treatment(n=6). In order to induce ankle sprain the right ankle joint was injured with 4~5 repetitive over-flexions and over-extensions manually. The severity of joint pain was evaluated by measuring foot weight bearing force ratio(FWBRF) of the hind limb and the injury-induced edema formation by diameter of the joint following ankle sprain. The changes of neural excitability in the lumbar spinal cord was tested by observation of cFos protein expression, a metabolic marker for neural excitation. Results : Severity of ankle injury induced in this experiment coincided with Grade 1 ankle sprain. Compared with ankle sprain group, ankle sprain＋taping showed a significant reductions of joint pain as well as of edema formation at the ankle joint following ankle sprain. There was significant upregulation of cFos-immunoreactive neurons in the lumbar spinal cord 24 hours after ankle sprain. In contrast, taping therapy resulted in significant inhibition of cFos-immunoreactive neurons in the lumbar spinal cord. Conclusions : Collectively, these results suggest that taping therapy may be an alternative therapeutic intervention for symptom recovery of the mild ankle sprain.

• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.877-885
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• 2000

Objective : The NOS inhibitors exhibit antinociceptive activity in rat model of neuropathic pain. NOS activity increases in the dorsal root ganglia(DRG) in neurop-athic pain. However, NOS activity decreases in the dorsal horn of spinal cord in the nerve injury models of neuropathic pain. To investigate whether the mechanism of decrease of NOS expression in the dorsal horn is related to a secondary effect resulting from increased NO production and likewise in the spinal DRG in the spinal nerve ligation model of neuropathic pain. Methods : We conducted behavioral tests for neuropathic pain, and nNOS immunohistochemistry and NADPH-diaphorase histochemistry after tight ligation of the 5th lumbar(L5) and 6th lumbar(L6) spinal nerves and L5 dorsal rhizotomy. Results : Typical neuropathic pain behaviors occurred 7 days after post-ligation in the neuropathic surgery group, but neuropathic pain behaviors in the dorsal rhizotomy group were absent or weak 7 days after post-operation. There was a decrease in the number of nNOS immunoreactive dorsal horn neurons on the both side(especially ipsilateral side) 7 days after post-ligation. The number of nNOS immunoreactive neurons in both side of the dorsal horn was not decreased 7 days after L5 dorsal rhizotomy. Conclusion : These data indicate that the changes in the injured DRG is essential for development and maintenance of neuropathic pain, and mechanism of decrease of nNOS expression in the dorsal horn is a secondary effect against the changes in the DRG including increased NO production in the spinal nerve ligation model of neuropathic pain.