• International Journal of Oral Biology
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• 제43권4호
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• pp.209-216
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• 2018

Reactive oxygen species (ROS) and nitrogen species (RNS) are involved in cellular signaling processes as a cause of oxidative stress. According to recent studies, ROS and RNS are important signaling molecules involved in pain transmission through spinal mechanisms. In this study, a patch clamp recording was used in spinal slices of rats to investigate the action mechanisms of $O_2{^{{\bullet}_-}}$ and NO on the excitability of substantia gelatinosa (SG) neuron. The application of xanthine and xanthine oxidase (X/XO) compound, a ROS donor, induced inward currents and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in slice preparation. The application of S-nitroso-N-acetyl-DL-penicillamine (SNAP), a RNS donor, also induced inward currents and increased the frequency of sEPSC. In a single cell preparation, X/XO and SNAP had no effect on the inward currents, revealing the involvement of presynaptic action. X/XO and SNAP induced a membrane depolarization in current clamp conditions which was significantly decreased by the addition of thapsigargin to an external calcium free solution for blocking synaptic transmission. Furthermore, X/XO and SNAP increased the frequency of action potentials evoked by depolarizing current pulses, suggesting the involvement of postsynaptic action. According to these results, it was estblished that elevated ROS and RNS in the spinal cord can sensitize the dorsal horn neurons via pre- and postsynaptic mechanisms. Therefore, ROS and RNS play similar roles in the regulation of the membrane excitability of SG neurons.

• Journal of Acupuncture Research
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• 제15권2호
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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.

• International Journal of Oral Biology
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• 제41권3호
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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 Physiology and Pharmacology
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• 제5권3호
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• pp.213-221
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• 2001

The amygdala is known as a site for inducing analgesia, but its action on the trigeminal nucleus has not been known well. Little information is available on the effect of dynorphin on NMDA receptor-mediated electrophysiological events in the trigeminal nucleus. The purpose of this study was to investigate the changes in the single neuron spikes at the trigeminal nucleus caused by the amygdala and the action of dynorphin on the trigeminal nucleus. In the present study, extracellular single unit recordings were made in the dorsal horn of the medulla (trigeminal nucleus caudalis) and the effects of microiontophoretically applied compounds were examined. When [D-Ala2, N-Me-Phe4, Glys5-ol]enkephalin (DAMGO, 10-25 mM), a ${\mu}-opioid$ receptor agonist, was infused into the amygdala, the number of NMDA-evoked spikes at the trigeminal nucleus decreased. However, the application of naloxone into the trigeminal nucleus while DAMGO being infused into the amygdala increased the number of spikes. Low dose (1 mM) of dynorphin in the trigeminal nucleus produced a significant decrease in NMDA-evoked spikes of the trigeminal nucleus but the NMDA-evoked responses were facilitated by a high dose (5 mM) of dynorphin. After the ${\kappa}$ receptors were blocked with naloxone, dynorphin induced hyperalgesia. After the NMDA receptors were blocked with AP5, dynorphin induced analgesia. In conclusion, dynorphin A exerted dose-dependent dual effects (increased & decreased spike activity) on NMDA-evoked spikes in the trigeminal nucleus. The inhibitory effect of the dynorphin at a low concentration was due to the activation of ${\kappa}$ receptors and the excitatory effect at a high concentration was due to activation of NMDA receptors in the trigeminal neurons.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제16권3호
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• pp.321-347
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• 1994

교근의 근방추에서 유래하여 단일 연접성 고유수용성 악반사에 관여하는 구심성 신경섬유를 단일 축삭내 HRP 주입기법으로 염색해서 삼차신경 운동핵에서의 type I a 및 type II 신경 섬유 종말부의 미세 구조 및 연접양상을 분석한 결과는 다음과 같았다. ${\cdot}$ 대부분의 표식 종말지는 dome, 길쭉한 형태 혹은 둥근 모양을 나타내었으며, scalloped 형태 혹은 glomerulus 형태는 관찰되지 않았다. ${\cdot}$ 표식 종말지는 다수의 균일한 형태 및 크기(49-52nm) 의 투명한 구형의 소포와 때때로 소수의 치밀소포(직경:87-114nm)를 함유하고 있었다. ${\cdot}$ 표식 종말지의 크기는 type I a가 장경($1.91{\pm}0.63{\mu}m$), 단경($0.94{\pm}0.28{\mu}m$) 및 평균 직경($1.42{\pm}0.40{\mu}m$)에서 type II보다 작았다(p<0.05). ${\cdot}$ 표식 종말지는 신경원체 혹은 가지돌기와 비대칭 연접을 이루었으며, 다형소포와 같은 연접소포들을 함유하는 종말부와의 연접은 관찰되지 않았다. ${\cdot}$ 대부분의 type I a (94.9%) 및 type II(85.9%) 종말지는 단지 1개의 neuronal propile과 연접을 이루었으며, 4개 이상의 neuronal propile들과 연접을 이루는 경우는 관찰되지 않았다. ${\cdot}$ type I a 종말지에 있어서 대부분(87.2%)은 신경원체 및 근심부 가지돌기와 연접을 이루는데 반해 type II 종말지는 다수가(64.8%) 원심부 가지돌기와 연접을 이루었으며 신경원체 및 근심부 가지돌기와 연접을 이루는 경우는 35.2%에 그쳤다. 이상을 종합해 보면 단일 연접성 악반사를 일으키는 구심성 신경섬유 종말부는 삼차운동신경핵에서, 동통 및 촉각 또는 감각분별등 복잡한 감각을 처리하는 감각핵에서 보다 연접후신경원에 강력한 흥분성 신호를 전달하며 또한 대단히 단순한 연접양상을 이루는 것으로 나타났다.