• The Korean Journal of Pain
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• v.31 no.3
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• pp.174-182
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• 2018

Background: The trigeminal nucleus caudalis (Vc) is a primary central site for trigeminal transmitting. Noxious stimulation of the trigeminal nociceptors alters the central synaptic releases and neural expression of some inflammatory and trophic agents. Orexin-A and the orexin 1 receptor (OX1R) are expressed in pain pathways including trigeminal pain transmission. However, the the mechanism(s) underling orexin-A effects on trigeminal pain modulation have not been fully clarified. Methods: Trigeminal pain was induced by subcutaneous injection of capsaicin in the upper lip in rats. The effect of trigeminal pain on cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) expression in the Vc of animals was determined by immunofluorescence. Subsequently, OX1R agonist (orexin-A) and antagonist (SB-334867-A) was administrated in the Vc to investigate the possible roles of the Vc OX1R on changes in COX-2 and BDNF levels following pain induction. Results: The data indicated an increase in COX-2 and decrease in BDNF immuno-reactivity in the Vc of capsaicin, and capsaicin- pretreated with SB-334867-A (80 nM), groups of rat. However, the effect of capsaicin on COX-2 and BDNF expressions was reversed by a Vc microinjection of orexin-A (100 pM). Conclusions: Overall, the present data reveals that orexin-A can attenuate capsaicin-induced trigeminal pain through the modulation of pain effects on COX-2 and BDNF expressions in the Vc of rats.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.369-382
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• 1998

The purpose of this study was finding the pain inhibitory effect of acupuncture at $LI_4$. The pain at dentes incisivi was evoked by noxious electric stimulation and EMG changes based on the interval were measured. To do this, the opioid antagonist was administered intraperitoneally. Following are some of results. 1. The pain inhibitory effect of acupuncture at $LI_4$ was 94.35%, 84.56%, 57.62%, 54.40%, at 10, 20, 30 and 40 minutes respectively. All the data were calculated based on 100% at 0 minute. The effect was very significant at 40 minutes. 2. The continuous effect of acupuncture at $LI_4$ after taking out the needle was 58.58%, 57.62%, 66.22%, 73.18%, 83.70%, 92.68%, at 50, 50, 70, 80, 90 and 100 minutes respectively. The overall continuous effect was shown its maximum 20 minutes after taking out the needle and reached to the initial value at 60 minutes. 3. The pain inhibitory effect following the naloxone administration and acupuncture application at $LI_4$ was 95.96%, 96.04%, 94.86%, 94.92% at 10, 20, 30 and 40 minutes respectively. All values showed similar tendency to the initial data. 4. The continuous effect of acupuncture at $LI_4$ after taking out the needle which was preceded by the naloxone administration was 94.48%, 96.02%, 96.02%, 98.00%, 98.46%, 97.18% at 50, 60, 70, 80, 90 and 100 minutes respectively. This trend was not a significant fluctuation. It was concluded that effect of acupuncture at $LI_4$ was shown in conjunction with secretion of analgesic substance. Therefore it is implied that the acupuncture application will play a major role in treating many diseases with more revelation of scientific acupuncture mechanism. Further studies of acupuncture manipulation are needed in the future based on our study.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.319-329
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• 1998

The purpose of this study was finding the pain inhibitory effect of acupuncture based on rataining time at LI -4. The pain at dentes incisor was evoked by noxious electric stimulation and digastric electromyogram(dEMG) changes based on time interval were measured. To do this, the opioid antagonist was administered intraperitoneally and four groups were made for convenience. Without naloxone, dEMG was changed by either retaining the needle for 40 minutes (Group I) or by lifting and thrusting the needle (Group II). With naloxone administration, dEMG was changed by either retaining the needle for 40 minutes (Group III) or by lifting and thrusting the needle (Group IV). The results are as following 1. The pain inhibitory effect of acupuncture at LI -4 was expressed best in Group I. 2. The pain inhibitory effect was somewhat expressed in Group II but the effect was smaller than Group I. 3 .In Groups III and IV, the pain inhibitory effect was not expressed. The overall result should be the foundation for the further studies to figure out the underlying mechanism of acupuncture. In addition, it is assumed that the results will be useful for optimal retaining time of acupucture for its maximal effect.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.287-300
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• 1998

The purpose of this study was finding the pain inhibitory effect of acupuncture at ST-36. The pain at dentes incisor was evoked by noxious electric stimulation and EMG changes based on time interval were measured. To do this, the opioid antagonist was administered intraperitoneally. Followings are some of the results. 1. The pain inhibitory effect of acupuncture at ST-36 was 93.82%, 87.00%, 75.30%, 69.76% at 10 20, 30 and 40 minutes respectively. All the data were calculated based on 100% at 0 minute. The effect was very significant at 40 minutes. 2. The continuous effect of acupuncture at ST-36 after taking out the needle was 77.46%, 79.66%, 87.60%, 91.50%, 95.14%, 99.48% at 50, 60, 70, 80, 90 and 100 minutes respectively. The overall continuous effect was shown its maximum 20 minutes after taking out the needle and reached to the initial value at 60 minutes. 3. The pain inhibitory effect following the naloxone administration and acupuncture application ST-36 was 93.44%, 94.58%, 90.80%, 88.04% at 10, 20, 30 and 40 minutes respectively. All values showed similar tendency to the initial data. 4. The continuous effect of acupuncture at ST-36 after taking out the needle which was preceded by the naloxone administration was 91.26%, 91.90%, 92.06%, 93.66%, 94.12%, 93.50% at 50, 60, 70, 80, 90 and 100 minutes respectively. This trend was not a significant fluctuation. It Was concluded that effect of acupuncture at ST-36 was shown in conjunction with secretion of analgesic substance. Therefore it is implied that the acupuncture application will play a major role in treating many diseases with more revelation of scientific acupuncture mechanism. Further studies of acupuncture manipulation are needed in the future based on our study.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.3
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• pp.717-728
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• 1996

The effects of electro-acupuncture on the pain threshold and the amplitude of dEMG(di-gastric EMG) evoked by the noxious electric stimulation on teeth and gingiva in dogs were studied. Experiments were carried out with 10 dogs weighing 5-8kg. Each animal was anestheticed with Entobar given intraperitoneally in an initial dose of 30mg/kg. Maintenance dose of 5mg/kg/hr was given through a cannula, in the femoral vein, as required to keep up light anesthesia. Bipolar stimulating wire electrodes, 0.1mm in diameter, insulated except for tips, were inserted into the upper canine and palatal gingiva. Rectangular aluminium plate electrodes (15$\times$5mm) were placed on acupuncture points, called Yin-Hsiang, located at both sides of the upper jaw. Rectangular biphasic current pulses of 2Hz, with a $250{\mu}sec$ duration, were delivered for 15 minutes. The dEMG activities were recorded from the anterior belly of the digastric muscle(one of the jaw opening muscles) using bipolar wire electrodes. The magnitude of the jaw opening reflex at different intensties of electro-acupuncture(1volt 4volt and 10volt) was estimated by averaging the 30 superimposed dEMGs recorded on an oscilloscope and audiomonitor. Data were analysed statistically with ANOV A and paired t-test. The obtained results were as follows: 1. Pain thresholds were increased 7.7 %, 15.4 %, 17.3 % in the teeth and 11.1 %, 19.0 %, 25.4 % in the gingiva as the intensities of electro-acupuncture increased incrementally. 2. Amplitudes of dEMG were decreaed 8.3%, 22.4%, 27.4% in the teeth and 9.8%, 36.5%, 42.2 % in the gingiva as the intensities of electro-acupuncture increased incrementally. 3. Inhibition of pain responses by the electroacupuncture was more effective in the gingiva than in the teeth.

• Restorative Dentistry and Endodontics
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• v.24 no.4
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• pp.614-622
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• 1999

Recent studies have implicated that more rostral components of the trigeminal spinal nucleus including subnucleus oralis (Vo) in orofacial nociceptive mechanisms. Since there is only limited electrophysiological evidence, the present study was initiated to characterize the receptive field and response properties of malls nociceptive neurons in chloralose/urethan-anesthetized rats. Single neuronal activity was recorded in right subnucleus oralis, and types of nociceptive neurons classified wide dynamic range (WDR), NS (nociceptive specific) and deep nociceptive (D) and the mechanoreceptive field (RF) and response properties were determined. A total of 34 nociceptive neurons could be subdivided into 17WDR neurons, 12NS neurons and 5D neurons. Vo nociceptive neurons had RF involving maxillary and/or mandibular divisions mainly located in the intraoral and/or perioral regions. Majority of Vo nociceptive neurons showed spontaneous activity less than 1Hz. The NS and D neurons activated only by heavy pressure and/or pinch stimuli had high mechanical thresholds compared to WDR neurons activated also by tactile stimuli. Vo nociceptive neurons showed a progressive increase of response to the graded mechanical stimuli. 39% of Vo nociceptive neurons received C-fiber electrical input as well as A-fiber electrical input from their RF, and 45% of them responded to electrical stimulation of the right maxillary first molar. 41% of Vo nociceptive neurons responded to noxious heat applied to their RF, and 18% of them showed an immediate burst of discharges following MO application to the right maxillary first molar pulp. These results indicate that Vo is involved in the transmission of nociceptive information mainly coming from intraoral or perioral region including tooth pulp.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.307-312
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• 1998

This study was performed to investigate the mechanism of central analgesic effects of antidepressants. Thirty four male rats were anesthetized with pentobarbital sodium (40 mg/kg, ip). A stainless steel guide cannula and a PE tube (PE10) were implanted into the lateral ventricle and cisterna magna area. Stimulating and recording electrodes were implanted into the incisor pulp and anterior digastric muscle. Electrodes were led subcutaneously to the miniature cranial connector sealed on the top of the skull with acrylic resin. The jaw opening reflex was used in freely moving rats, and antidepressants were administered intracisternally in order to eliminate the effects of anesthetic agents on the pain assessment and evaluate the importance of the central action site of antidepressants. After 48 hours of recovery from surgery, digastric electromyogram (dEMG) of freely moving rats was recorded. Electrical shocks (200 ${\mu}sec$ duration, 0.5-2 mA intensity) were delivered at 0.5 Hz to the dental pulp every 2 minute. Intracisternal administration of $15\;{\mu}g$ imipramine suppressed dEMG elicited by noxious electrical stimulation in the tooth pulp to $76{\pm}6%$ control. Intracisternal administration of $30\;{\mu}g$ desipramine, nortriptyline, or imipramine suppressed dEMG remarkably to $48{\pm}2,\;27{\pm}8,\;or\;25{\pm}5%$ of the control, respectively. Naloxone, methysergide, and phentolamine blocked the suppression of dEMG produced by intracisternal antidepressants from $23{\pm}2\;to\;69{\pm}4%,\;from\;32{\pm}5\;to\;80{\pm}9%,\;and\;from\;24{\pm}6\;to\;77{\pm}5%$ of the control, respectively. These results indicate that antidepressants produce antinociception through central mechanisms in the orofacial area. Antinociception of intracisternal antidepressants seems to be mediated by an augmentation of descending pain inhibitory influences on nociceptive pathways.

• Journal of Veterinary Clinics
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• v.27 no.2
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• pp.136-141
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• 2010

The aim of this study is to investigate whether medetomidine (MED) and tiletamine/zolazepam (ZT) combination in dogs provide the sufficient analgesia during the period of the stage of surgical anesthesia determined by the response to the noxious stimuli, which were evaluated by the change of electroencephalogram (EEG) and hemodynamic values. Seven clinically healthy, adult beagle dogs were used. They were used repeatedly at interval of a week, according to a randomized design. This study had 2 experimental groups. In Group 1, dogs received $30\;{\mu}g/kg$ of medetomidine and 10 mg/kg of tiletamine/zolazepam. Both drugs were administered intramuscularly. In Group 2, dogs were medicated with the same method as in Group 1, except the pedal withdrawal reflex test was done. In Group 2, interdigital regions were grasped with a mosquito forceps for 30 seconds, every 5 min from 10 min to 45 min after ZT injection. During all recording stages, the power for each band, mean arterial pressure and heart rates were calculated. On EEG, no significant changes were observed between groups. Although mean arterial pressure and heart rate were increased 10 min after ZT injection, no significant differences were observed between groups. In conclusion, the MED and ZT anesthesia in dogs are seemed to provide a satisfactory analgesic effect during the period of surgical anesthesia based on EEG with pedal withdrawal reflex test.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.698-706
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• 2019

Over the last few decades, there have been a lot of efforts to develop soft actuators, which can be external stimuli-responsive and applied to the human body. In order to fabricate medical soft actuators with a dynamic precision control, the 3D crosslinked poly(acrylic acid) (PAAc)/poly(vinyl alcohol) (PVA)/poly(ethylene glycol) (PEG) hydrogels were synthesized in this study by using a radiation technique without noxious chemical additives or initiators. After irradiation, all hydrogels showed high gel fraction over 75% and the ATR-FTIR spectra indicated that PAAc/PVA/PEG hydrogels were successfully synthesized. In addition, the gel fraction, equilibrium water content, and compressive strength were measured to determine the change in physical properties of PAAc/PVA/PEG hydrogels according to the irradiation dose and content ratio of constituents. As the irradiation dose and amount of poly(ethylene glycol) diacrylate (PEGDA) increased, the PAAc/PVA/PEG hydrogels showed a high crosslinking density and mechanical strength. It was also confirmed that PAAc/PVA/PEG hydrogels responded to electrical stimulation even at a low voltage of 3 V. The bending behavior of hydrogels under an electric field can be controlled by changing the crosslinking density, ionic group content, applied voltage, and ionic strength of swelling solution.

• Journal of Korean Physical Therapy Science
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• v.13 no.2
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• pp.99-119
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• 2006

Endothelin (ET) is a 21 amino acid peptide with multifunctional effects on the vasculature as well as a variety of other cell types such as respiratory, gastrointestinal, urogenital, endocrine, central nervous systems, and others. Endothelin has emerged as a modulator by autocrine and paracrine actions for many cellular activities, including vasoconstriction, cell proliferation, hormone production, neurotransmitter and/or neuromodulator. The endothelin family consists of three closely related peptides, ET-1, ET-2, and ET-3 derived from separate genes, such as chromosome 6, 1, and 20, respectively. ET-1 is the predominant isoform produced in the cardiovascular system and about which most is known. Endothelin receptors are seven-transmembrane GTP-binding protein-coupled receptors, which are classified into endothelin-A (ETA) and endothelin-B (ETB) receptors. Interestingly, recent evidence is accumulating to suggest that ET -1 may contribute to a variety of pain states such as allodynia and hyperalgesia in animals and humans. Therefore, in this review the biological characteristics and contraction-related mechanism of endothelin-1 in mammalian cells will be summarized. Especially, we focus on multifunctional roles for ET-1 in noxious stimulation-induced pain for the study of pain specialized physical therapy.