Role of microglial activation on neuronal excitability in rat substantia gelatinosa

Areum,Park,Sang,Woo,Chun 대한구강생물학회 2020 International Journal of Oral Biology Vol.45 No.4

Glial cells, including astrocytes and microglia, interact closely with neurons and modulate pain transmission, particularly under pathological conditions. In this study, we examined the excitability of substantia gelatinosa (SG) neurons of the spinal dorsal horn using a patch clamp recording to investigate the roles of microglial activation in the nociceptive processes of rats. We used xanthine/xanthine oxidase (X/XO), a generator of superoxide anion (O2∙–), to induce a pathological pain condition. X/XO treatment induced an inward current and membrane depolarization. The inward current was significantly inhibited by minocycline, a microglial inhibitor, and fluorocitrate, an astrocyte inhibitor. To examine whether toll-like receptor 4 (TLR4) in microglia was involved in the inward current, we used lipopolysaccharide (LPS), a highly specific TLR4 agonist. The LPS induced inward current, which was decreased by pretreatment with Tak-242, a TLR4-specific inhibitor, and phenyl N-t-butylnitrone, a reactive oxygen species scavenger. The X/XO-induced inward current was also inhibited by pretreatment with Tak-242. These results indicate that the X/XO-induced inward current of SG neurons occurs through activation of TLR4 in microglial cells, suggesting that neuroglial cells modulate the nociceptive process through central sensitization.

흰쥐의 위축된 저작근에 대한 간헐적 전기자극 효과

천상우,박병림,한두석 대한구강생물학회 1992 International Journal of Oral Biology Vol.16 No.2

This study was designed to evaluate the effect of intermittent electrical stimulation on atrophied masseter muscle in the rat(230-250g). Growing Sprague-Dawley rats(80g) were assigned to either a control(CONT), a soft dieted(SOFT), or a soft dieted plus intermittent electrical stimulation(SOFT-ES) group. CONT group was continued to receive an ordinary hard rat diet and SOFT group received an ordinary diet in a ground form, mixed with water in a proportion of 2:5, for 6 weeks. After 6 weeks of soft diet feeding in SOFT group, mechanical properties of contraction in the masseter muscle were measured by means of isometric force transducer and then electrodes were implanted to the masseter muscle for intermittent electrical stimulation(SOFT-ES group). In SOFT-ES group, electrical stimulation was applied directly to the masseter muscle for 2 weeks at supramaximal intensity, 0.3ms, 20Hz for 15 minutes every 6 hours. After electrical stimulation for 2 weeks, mechanical properties and fatigue tendency of the masseter muscle were observed. The results were as follows. 1. Twitch tension was no significant difference according to the mandibular position, however, tetanic tension at 11㎜ interincisal distance was larger than at 7㎜. 2. In SOFT group, tetanic tension and contraction time were decreased, and fatigue tendency was increased compared with the control group. 3. In SOFT-ES group, tetanic tension was increased and fatigue tendency was decresed compared with the soft dieted group, however, all mechanical properties of muscle contraction were similiar to those of the control group. 4. Effects of electrical stimulation in atrophied muscle were more prominant in tension-related properties than speed-related properties. These data suggest that intermittent electrical stimulation may be useful in prevention and treatment of muscle atrophy.

Capsaicin과 Paradol이 구강내 유해자극에 의한 개구반사와 신경흥분 전달에 미치는 영향

최동주,신일영,김중수,이종흔 대한구강생물학회 1988 International Journal of Oral Biology Vol.12 No.2

This study was performed to elucidate the analgesic mechanism of paradol and to compare effects of paradol with those of dihidrocapscaicin(DHC). Rabbits(2-2.5kg both sexes) were anesthetized with pentobarbital sodium(30mg/kg I.V.), and cannulated in trachea and external jugular vein. To observe effects on jaw opening reflex, inferior alveolar nerve(IAN) of both sides were exposed for drug application, and wire electrodes were inserted in anterior belly of digastric muscle for recording of EMGs of anterior belly of digastric muscle(dEMG) and in oral mucosa covering mental foramen for applying noxious stimulation. dEMGs evoked by noxious stimulation with double intensity of threshold for digastric EMG were recorded in magnetic tape recorder. To observe effects on action potential, saphenous nerve were exposed, and three tissue pools were made from surrounding tissue. The most distal pool was used for applying stimulation, the most proximal one for recording of action potentials, and the other on for drug application. Action potentials evoked by 200 folds intensity of threshold for most sensitive fiber were recorded in magnetic tape recorder. One side of IAN and saphenous nerves were used for DHC or paradol applications, the other side of nerves for control experiments(only vehicle application). Vehicle consisted of 10% Tween 80, 10% ethanol and 80% physiological saline(v/v), and drugs were solubilized in vehicle for 1.5% concentration(w/v). dEMGs and action potentials were recorded before drug application, immediate after 30 minutes drug application, at 30 and 60 minutes after drug had been washed out. DHC application on IAN could not influence on dEMG, but paradol application decreased the amplitude of dEMG. In action potential experiments, DHC decreased amplitude and conduction velocity of only C fiber, while paradol did those of C-fiber and Aδ-fiber.

삼차신경 감각핵의 세포활성도와 Substance P 유리에 대한 Capsaicin, Paradol 및 Shogaol의 전통작용기전에 관한 연구 : Ⅰ. 유해자극에 의한 개구반사와 삼차신경 척수감각핵의 Substance P에 미치는 영향 Ⅰ. EFFECTS ON JAW OPENING REFLEX BY NOXIOUS STIMULUS AND RELEASE OF SUBSTANCE P

이종흔,김중수,송형근,박수정,함진숙 대한구강생물학회 1990 International Journal of Oral Biology Vol.14 No.1

The purpose of this investigation was to determine the relative analgesic effectiveness of paradol and shogaol compared with capsaicin, and effects of capsaicinoids on substance P of trigeminal spinal sensory nucleus. Under anesthesia, anterior belly of digastric muscle was exposed and a pair of electrodes was inserted to record the electromyograms. Noxious electrical stimulus was applied to oral mucosa around the mental foramen. Inferior alveolar nerves (IAN) and saphenous nerves were carefully exposed for application of vehicle and drugs to evaluate the effects on digastric EMG (dEMG) and neural conduction, and caudal part of brainstem was exposed to determine the substance P. Vehicle and 1.5% of capsaicin, paradol and shogaol were applied to IAN and saphenous nerves for 30 minutes, respectively. EMG_s of digastric muscle evoked by noxious electrical stimulus were recorded before application of drugs or vehicle, immediately after removal and washing of drugs and at 30 minutes after washing. To examine the effects of the peripheral stimulation on the action potential, stimulating electrodes were placed on the peripheral side of drugs application site and recording electrodes were on the proximal side. Substance P of trigeminal spinal sensory nucleus was collected by push-pull perfusion technique and determined by radioimmunoassay. Capsaicin application on IAN could not influence on dEMG, but paradol and shogaol decrease the amplitude of dEMG. Capsaicin applied locally to nerve decreased amplitude and conduction velocity of only C-fiber, while paradol and shogaol inhibited the neural conduction of C-fiber and Aδ-fiber. Substance P in the trigeminal spinal nucleus was reduced by capsaicin but not by paradol and shogaol.

Periaqueductal Gray와 구강 점막 자극이 뇌간의 5-Hydroxy tryptamine 과 Methionine-Enkephalin의 함량에 미치는 영향

김경년,김중수,이종흔 대한구강생물학회 1987 International Journal of Oral Biology Vol.11 No.2

This experiment was carried out to clarify the role of 5-Hydroxytryptamine (5-HT) and methionine-enkephalin (MENK) on the analgesia produced by periaqueductal gray (PAG) or oral mucosa stimulation in orofacial pain. Experimental rats were divided into normal and 5,7-dihydroxytryptamine (DHT) treated group and each group was subdivided into control, oral mucosa stimulation and PAG stimulation group. The DHT treated group were injected DHT creatinine sulfate complex 400㎍ in anterior horn of lateral cerebral ventricle as described by Bjo¨rklund (1975). After two weeks, PAG was stimulated 200μsec, 200Hz, 200㎂ for 15 minutes. and oral mucosa was done five pulses of 500μsec, 200Hz per second for 15 minutes. We determined the content of 5-HT and MENK in midbrain, pons and medulla oblongata with high performance liquid chromatography and radioimmunoassay, respectively. 5-HT and 5-HIAA were significantly increased by PAG or oral mucosa stimulation in pons and medulla oblongata (P<0.05). And MENK was significantly decreased by PAG stimulation in medulla oblongata (P<0.05), but oral mucosa stimulation evoked only slight decrease of MENK content in medulla oblongata. These effects were not observed in DHT treated group.

High dose of QX-314 produces anti-nociceptive effect without capsaicin in rats with inflammatory TMJ pain

Yang,,Kui-Ye,Kim,,Min-Su,Kim,,Eun-Kyung,Kong,,Mi-Sun,Ahn,,Jong-Soo,Lee,,Jong-Hun,Ju,,Jin-Sook,Ahn,,Dong-Kuk 대한구강생물학회 2013 International Journal of Oral Biology Vol.38 No.4

이상의 실험 결과들을 요약하면, 포르말린을 측두하악관절 내로 주입하여 발생한 염증성 통증 행위반응은 QX-314의 투여로 감소할 수 있었다. 저농도의 QX-314의 진통작용은 TRPV1 통로를 이용하여 세포막 내로 이동하여 작용이 나타났으며 고농도의 QX-314는 TRPV1 통로와 무관하게 진통작용을 나타내었다. 이와 같은 결과는 측두하악관절 장애로 인해 발생되는 염증성 통증에 QX-314가 효과적인 치료제로 사용할 수 있다는 것을 말해주며, 특히 고농도의 QX-314가 세포막을 이동하는 경로에 대한 연구가 더 진행된다면 임상에서 QX-314가 진통제로서 사용할 수 있는 계기가 될 것으로 판단된다. The present study investigated the effects of QX-314 on inflammatory pain of the temporomandibular joint (TMJ). Experiments were carried out on male Sprague-Dawley rats weighing 220-280 g. Under anesthesia, the TMJ of each animal was injected with $50{\mu}L$ of formalin (5%). The number of noxious behavioral responses, including rubbing or scratching of the facial region including the TMJ area, was recorded over 9 sequential 5 min intervals for each animal. Although 2.5% QX-314 did not affect formalin-induced nociceptive behavior, administration of 5% QX-314 with formalin significantly decreased the number of scratches produced by the formalin injection. Co-administration of capsaicin, a TRPV1 agonist, with 2.5% QX-314 produced significant anti-nociceptive effects whereas 2.5% QX-314 alone did not. However, the co-administration of capsaicin did not enhance the anti-nociceptive effects in the 5% QX-314-treated rats. Moreover, the co-administration of capsazepine, a TRPV1 antagonist, did not attenuate anti-nociceptive effects in the 5% QX-314-treated rats. These findings suggest that TRPV1 is effective in the transport of low but not high doses of QX-314. Moreover, a high dose of QX-314, which is not mediated by peripheral TRPV1 activity, may be viable therapeutic strategy for inflammatory pain in the TMJ.

Streptococcus mutans gtfD 유전자 발현에 대한 당의 영향

Kim,,Hyun-Jin,Chung,,Jin 대한구강생물학회 2003 International Journal of Oral Biology Vol.28 No.3

수용성 글루캔을 합성하는 효소인 glucosyltransferase D의 mRNA 발현에 대한 각 당의 Flurescent in situ hybridization (FISH)으로 관찰하여 다음의 결과를 얻었다. 1. 설탕의 첨가된 경우 gtfD 유전자의 mRNA가 발현되었다. 2. 1% 설탕이 첨가된 BHI 액체 배지에 당을 첨가한 경우 포도당은 10% 일 때, 과당은 5%, 10%에서 gtfD 유전자의 mRNA 발현이 감소되었다. 3. 자일리톨의 경우 1%에서는 gtfD 유전자의 mRNA 발현이 대조군보다 증가하였으나 5%, 10%에서는 감소하였다. 4. 유당과 솔비돌의 경우 농도에 관계없이 gtfD 유전자의 mRNA 발현에 거의 영향을 주지 않았다. 결론적으로 수용성 글루캔을 합성하는 gtfD 유전자의 발현이 10% 포도당. 5% 와 10%의 과당 및 자일리톨 첨가에 의해 감소됨을 알 수 있었다. Glucan is one of the components of oral biofilm which is synthesized from sucrose through the action of glucosyltransferase (GTF) produced by oral streptococci. The intake and the concentration of sugars in a mouth can affect on the glucan synthesis. In present study, the effects of various sugars on the mRNA expression of gtfD of Streptococcus mutans were examined by Fluorescent in situ hybridization (FISH). The mRNA of gtfD was expressed normally in the BHI broth containing 1% sucrose. The mRNA expression was decreased by the addition of 10% of glucose, and 5 % and 10% of fructose. Lactose and sorbitol had little effect on the mRNA expression of gtfD. 5% and 10% of xylitol reduced the mRNA expression of gtfD, while 1% of xylitol enhanced the expression when compared to the control. In summary, the mRNA expression of gtfD was decreased by the addition of glucose, fructose, or xylitol.

치아우식 저항성군과 감수성군의 Streptococcus mutans에 대한 혈청과 이하선 타액의 자연항체 수준

한철민,송요한,김각균,최선진 대한구강생물학회 1991 International Journal of Oral Biology Vol.15 No.2

The levels of serum and parotid salivary antibodies from dental caries resistant(CR) (DMFT=0) and caries-susceptible(CS) (DMFT≥10) subjects to Streptococcus mutans were determined. In addition, the ability of serum and saliva containing these antibodies to neutralize S. mutans virulence activities was tested. S. mutans cells to be used as antigens were grown in either non-dialyzed or dialyzed Todd-Hewitt medium. The antibody titers were determined by enzyme-linked immunosorbant assay. The level of serum IgG antibody to S. mutans whole cell antigen was significantly higher in CR individuals than in CS subjects. This difference in antibody levels between CR and CS groups was observed only when the whole cell antigen was prepared in dialyzed medium. No difference in salivary antibody levels was detected between the two groups. The sera and salivas were found not to be able to neutralize the virulence activities of this organism. The present study suggests that anti-S. mutans IgG antibodies in human serum have a role in the control of dental caries.

Whole-genome DNA 프로브를 이용한 구강 Bacteroides 균종의 식별

최세원,이정숙,최선진,김각균 대한구강생물학회 1992 International Journal of Oral Biology Vol.16 No.1

The need for a rapid and sensitive microbiological assay has become necessary for both research and clinical diagnostic. This need has become clear as a result of extensive documentation linking specific bacterial species and periodontal destruction. DNA probe technology seems to be able to provide both a sensitive and specific assay and may be able to alleviate the concern for transport of fastidious microorganisms. We have been trying to establish the method of identifying the periodontopathic microorganisms by DNA probe. As the first step we tried to know if whole-genomic DNA probe could differentiate between bacterial species, using three different serotype-strains of both bacteroides gingivalis and bacteroides intermedius. Also we tested if there is any cross-hybridization between bacteroides spp· and Streptococcus spp. The experimental procedures were as follows: anaerobic culture of bacterial cells, preparation of whole-genomic DNA from bacteria and measurement of DNA concentration, immobilization of DNA onto a nitrocellulose filter using dot-blot apparatus after 2-fold serial dilution of DNA, radio-labelling of DNA with ^32P by random oligonucleotide-primed synthesis, which would serve as a DNA probe, blocking unbound nitrocellulose with 0.05×BLOTTO, hybridization of the filter with ^32P-labelled probe, and washing and detection of bound probe by autoradiography. The results were as follows. The whole-genomic DNA probe of B. gingivalis strain 381 (serotype a) was able to hybridize with all three serotypes a, b, and c) of the species. Also, the whole-genomic DNA probe of B. intermedius strain 9336 (serotype b) was able to hybridize with all three serotypes of the species. There was no detectable cross-hybridization between B. gingivalis and B. intermedius or bacteroides DNA probe with streptococcal DNA, within the range of DNA amount used in the experiment. The DNA probe was able to detect 3ng of homologous DNA in a dot. It seems likely that whole-genomic probe could be used for identification of Bacteroides spp, in the clinical samples using DNA probe, if a suitable method to lyse the cell on the filter is provided.

단백 도말한 Hydroxyapatite와 구강 Streptococci와의 상호반응에 관한 연구

신현규,이시영,최선진 대한구강생물학회 1988 International Journal of Oral Biology Vol.12 No.2

Effect of human and animal sera and a serum protein on the adherence of oral streptococci to hydroxyapatite bead was investigated by standard adherence assay procedure. Sucrose effect on bacterial adherence to saliva-coated HA (SHA) bead was also studied. It was examined whether bead-adhered bacterial cells remained attached to or detach from bead in scintillant, because sample self-absorption could take place. Animal sera and BSA decreased bacterial adherence to HA. BSA concentration as high as 10mg/ml inhibited the adherence up to 87%. When HA bead pre-coated with BSA was treated with saliva, no difference in the extent of adherence was observed as compared to the control bead treated only with saliva. S. mutans strain 10449 among several other strains and a strain of S. sanguis showed the fastest agglutination upon addition of sucrose. S. mutans cells exposed to sucrose to permit extracellular polysaccharide synthesis before or during adherence attached in fewer numbers to both HA and SHA than control organisms. This may be due to a formation of large-sized aggregates. HA bead-adhered bacterial cells in scintillation fluid remained attached during scintillation counting, thus raising a possibility of sample self-absorption in radioisotope counting rate.