• BMB Reports
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• 제49권9호
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• pp.474-487
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• 2016

Itch is one of the most distressing sensations that substantially impair quality of life. It is a cardinal symptom of many skin diseases and is also caused by a variety of systemic disorders. Unfortunately, currently available itch medications are ineffective in many chronic itch conditions, and they often cause undesirable side effects. To develop novel therapeutic strategies, it is essential to identify primary afferent neurons that selectively respond to itch mediators as well as the central nervous system components that process the sensation of itch and initiate behavioral responses. This review summarizes recent progress in the study of itch, focusing on itch-selective receptors, signaling molecules, neuronal pathways from the primary sensory neurons to the brain, and potential decoding mechanisms based on which itch is distinguished from pain.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제15권4호
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• pp.281-301
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• 1993

단일축삭내 HRP 주입기법에 의해 서순응형 치근막 기계적자극수용기에서 오는 일차구심성 신경섬유증 무수축삭에 의해 연결되어 있는 종말지의 시냅양상 및 미세구조에 대한 연구결과는 다음과 같았다. 1. 표식된 stem collateral은 첫 bouton을 형성할 때까지는 수질을 함유하고 있었으며, 그 직경은 약 $0.81-1.38{\mu}m$이었고, 각 terminal bouton은 특징적으로 모두가 무수축삭에 의해 연결되어 있었다. 2. 대부분의 표식 bouton은 dome형태를 나타내었으며, 때때로 길쭉한 모양 혹은 둥근모양의 bouton도 다소 관찰되었으나 scalloped 형태 혹은 glomerulus 형태의 bouton은 전혀 나타나지 않았으며 각 표식 bouton은 균일한 형태 및 크기(직경 $47.60{\pm}3.58{\mu}m$)를 가진 밝은 타원 및 원형의 소포들을 함유하고 있었다. 3. 표식 bouton은 평균직경 $1.15{\pm}0.24{\mu}m$로서 비교적 작았고 평균 $1.11{\pm}0.31$개의 다른 neuronal propile과 시냅스를 이루었는데 그중 단 1개의 neuronal propile과 시냅스를 이루는 것이 89.4%, 2개의 neuronal propile과 시냅스를 이루는 것이 10.6%로서 대단히 단순한 형태의 시냅스를 이루는 것이 특징적으로 나타났으며, 그중 대부분(80.03%)이 dendritic shaft 혹은 spine과만 시냅스를 이루었으며 p-ending과 시냅스를 이루는 것은 6.1%였고 synaptic triad는 전혀 관찰되지 않았다.

• Applied Microscopy
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• 제38권4호
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• pp.375-382
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• 2008

삼차신경주감각핵에서 치수유래 일차들신경섬유의 종말과 그에 연접하는 연접이전신경종말에 함유된 연접소포들을 형태학적으로 비교하기 위하여 신경추적자(WGA-HRP)를 흰쥐 앞니의 치수강에 주입하여 치수 유래 일차들신경종말을 표식한 후, 투과형 전자현미경을 통한 미세구조적 정량 분석을 실시하였다. 표식된 치수유래 일차들신경종말은 직경이 $45{\sim}55\;nm$인 구형의 소포를 함유하고 있었으며, 일부 직경이 $80{\sim}120\;nm$ 큰 치밀소포가 관찰되기도 하였다. 또한 표식된 신경종말은 다형성 연접소포를 함유하고 있는 연접이전신경종말과 대칭연접을 이루고 있었다. 일차들신경종말의 연접소포들은 긴 지름에 대한 짧은 지름의 비율(form factor)이 $0.6{\sim}0.99$의 분포를 보인 반면, 연접이 전신경종말의 연접소포들은 $0.25{\sim}0.99$까지 다양하게 나타났다. 또한 대부분의 연접이전신경종말은 GABA에 대한 면역양성반응을 보였다. 이상의 결과는 표식된 신경종말과 그에 연접하는 연접이전신경종말의 연접소포는 서로 다른 형태를 보이고 있으며, 또한 그 연접이전신경종말이 억제성 신경전달물질인 GABA를 함유하고 있음을 나타낸다.

• Biomolecules & Therapeutics
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• 제3권4호
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• pp.256-259
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• 1995

Antinociceptive and desensitizing effects of systemically administered capsaicinoids (capsaicin and KR25018) were investigated in guinea pig. Nociceptive sensitivity to chemical stimulus was examined to test sensory function, and the content of substance P-like immunorractivity (SP-LI) in bronchi was determined as a peripheral marker of capsaicin-sensitive primary afferent neurons. Guinea pigs were pretreated s.c. with several doses of capsaicin (1,2.5,5, 10 mg/kg) or KR25018 (1, 2.5, 5, 10 mg/kg) one week prior to the experiments. Frequency of eye wiping was significantly decreased by capsaicin and KR25018 in a pretreatment dosedependent manner. In capsaicin- or KR25018-pretreated guinea pigs, there was a significant loss of SP-LI in bronchial tissue extracts. In summary, a newly synthesized capsaicin analogue H725018 exhibited antinociceptive effect against chemical stimulus in guinea pig, with comparable potency to capsaicin. This desensitizing activity of capsaicin or KR25018 might be related to the loss of SP-LI in peripheral afferent nerves.

• 대한치과의사협회지
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• 제48권5호
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• pp.365-370
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• 2010

Herpes virus family is highly infectious to patients, their families and dentists. The diagnosis of herpes infection is based on the characteristic clinical appearance and the location of the lesions. Herpes Simplex Virus(HSV) usually acquired through direct contact with infected lesions or body fluids, and the prevalence of HSV infection increases progressively from childhood. Primary infections provoke herpetic gingivostomatis typically affects the tongue, lips, gingival, buccal mucosa and palate. Recurrent infections give rise to vesiculo-ulcerative lesions at vermilion border of lip(herpes labialis). In the form of chickenpox, Varicella Zoster Virus(VZV) usually is infected in childhood. VZV spreads in the affected primary afferent nerve to the skin and produces a vesicular rash and pain. Epstein-Barr Virus(EBV) infects B cells and cause infectious mononucleosis. Latent EBV infection has also been implicated in Burkitt lymphoma, nasopharyngeal carcinoma. Cytomegalovirus(CMV) is associated with immune-compromised patient such as organ transplantation and AIDS patients.

• 한국식품영양과학회지
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• 제32권4호
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• pp.645-653
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• 2003

Taste receptor cells respond to gustatory stimuli using a complex arrangement of receptor molecules, signaling cascades and ion channels. When stimulated, these cells produce action potentials that result in the release of neurotransmitter onto an afferent nerve fiber that in turn relays the identity and intensity of the gustatory stimuli to tie brain. A variety of mechanisms are used in transducing the four primary tastes. Direct interaction of the stimuli with ion channels appears to be of particular importance in transducing stimuli reported as salty or sour, whereas tile second messenger systems cyclic AMP and inositol trisphosphate are important in transducing bitter and sweet stimuli. In addition to the four basic tastes, specific mechanisms exist for the amino acid glutamate, which is sometimes termed the fifth primary taste. The emerging picture is that not only do individual taste qualities use more than one mechanism, but multiple pathways are available for individual tastants as well.

• Journal of Oral Medicine and Pain
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• 제30권1호
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• pp.87-106
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• 2005

삼차신경계의 일차연접부위에서 구강 및 악안면 영역의 저역치기계자극수용기에서 유래하는 감각정보의 전달 및 처리 기전을 이해하고자, 고양이 콧수염에서 유래하는 들신경섬유를 사용하여 단일축삭 내 기록법에 의해 HRP를 표식한 후, 삼차신경중간핵에서 시편을 제작하고 표식종말에 대한 연속절편을 형성하였다. 총 30개의 표식 신경종말을 대상으로 전자현미경을 이용하여 삼차신경중간핵에서의 신경섬유 종말 및 연접이전축삭종말의 미세구조적 특징, 발현빈도, 연접양식 등을 분석하여 다음과 같은 결과를 얻었다. 1. 표식종말은 직경 45$\sim$55 ㎚의 균일한 형태의 밝고 둥근 모양의 연접소포를 함유하고 있었으며, 가지돌기와는 연접이후 치밀질이 잘 발달되어 있고, 연접틈새가 크며, 여러 곳에서 넓은 연접구조를 보이는 비대칭연접을, 다형의 연접소포를 함유하는 비표식 축삭종말과는 연접이후 치밀질이 뚜렷하게 발달되지 않으며, 연접면적이 좁은 대칭연접을 형성하였다. 2. 각 표식종말은 인접한 신경구조물들과 최소 1개에서부터 최대 15개까지 신경연접을 형성하여 단위 표식종말 당 평균 4.77$\pm$3.37개의 신경연접이 관찰되었으며, 5개 이상의 신경구조물들과 연접을 형성하는 비교적 복잡한 연접양상이 다수의 표식종말(46.7%, n=14)에서 관찰되었다. 3. 표식종말이 세포체와 직접 연접하는 양상은 관찰되지 않았으며, 가지돌기와는 단위 표식종말 당 1.83$\pm$1.37개의 신경연접을 형성하였다. 가지돌기와 연접을 이루는 표식종말의 대부분(85.0%)은 원위부 가지돌기인 가지돌기체와 연접을 이루었으며(n=47, 1.57$\pm$1.38/1 bouton), 근위부 가지돌기(n=6, 0.20$\pm$0.41/1 bouton)나 가지돌기 가시(n=2, 0.07$\pm$0.25/1 bouton)와 연접을 이루는 경우는 드물었다. 4. 표식종말의 76.7%(n=23)에서 다양한 형태의 연접소포를 함유하는 축삭종말인 p-ending과 축삭사이연접을 형성하였으며 (2.93$\pm$2.36/1 bouton), p-ending이 표식종말 및 이에 연접하는 가지돌기와 동시에 연접을 형성하는 연접세동이도 60.0% (n=18)에서 관찰되었다. 이상의 결과를 종합하여 보았을 때, 고양이 콧수염에서 유래하는 들신경섬유 종말은 삼차신경중간핵에서 특징적인 연접양상을 나타내었으며, 이는 감각정보의 분별, 통각의 정동반응 등 복잡한 감각정보의 처리에 관여하는 삼차신경중간핵의 기능과 밀접한 상관관계가 있는 것으로 사료되며, 향후 신경종말의 미세구조에 대한 정량적인 분석과 연접이전 억제에 관여하는 신경전달물질의 동정 등 생리학적인 기능에 대한 더욱 광범위한 연구가 필요하리라고 사료된다.

• Journal of Korean Neurosurgical Society
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• 제43권2호
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• pp.97-104
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• 2008

Objective: Transient receptor potential vanilloid subfamily type 1 (TRPV1), a most specific marker of the nociceptive primary afferent, is expressed in peptidergic and non-peptidergic primary afferents innervating skin and viscera. However, its expression in sensory fibers to skeletal muscle is not well known. In this study, we studied the neurochemical characteristics of TRPV1-positive primary afferents to skeletal muscles. Methods: Sprague-Dawley rats were injected with total $20{\mu}l$ of 1% fast blue (FB) into the gastrocnemius and erector spinae muscle and animals were perfused 4 days after injection. FB-positive cells were traced in the L4-L5 (for gastrocnemius muscle) and L2-L4 (for erector spinae muscle) dorsal root ganglia. The neurochemical characteristics of the muscle afferents were studied with multiple immunofluorescence with TRPV1, calcitonin gene-related peptide (CGRP) and $P2X_3$. To identify spinal neurons responding to noxious stimulus to the skeletal muscle, 10% acetic acids were injected into the gastrocnemius and erector spinae muscles and expression of phospho extracellular signal-regulated kinase (pERK) in spinal cords were identified with immunohistochemical method. Results: TRPVl was expressed in about 49% of muscle afferents traced from gastrocnemius and 40% of erector spinae. Sixty-five to 60% of TRPV1-positive muscles afferents also expressed CGRP. In contrast, expression of $P2X_3$ immnoreaction in TRPV1-positive muscle afferents were about 20%. TRPV1-positive primary afferents were contacted with spinal neurons expressing pERK after injection of acetic acid into the muscles. Conclusion: It is consequently suggested that nociception from skeletal muscles are mediated by TRPV1-positive primary afferents and majority of them are also peptidergic.

• The Korean Journal of Physiology and Pharmacology
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• 제8권5호
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• pp.281-288
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• 2004

The present study was undertaken to confirm whether melittin, a major constituent of whole bee venom (WBV), had the ability to produce the same nociceptive responses as those induced by WBV. In the behavioral experiment, changes in mechanical threshold, flinching behaviors and paw thickness (edema) were measured after intraplantar (i.pl.) injection of WBV (0.1 mg & 0.3 mg/paw) and melittin (0.05 mg & 0.15 mg/paw), and intrathecal (i.t.) injection of melittin $(6{\mu}g)$. Also studied were the effects of i.p. (2 mg & 4 mg/kg), i.t. $(0.2{\mu}g\;&\;0.4{\mu}g)$ or i.pl. (0.3 mg) administration of morphine on melittin-induced pain responses. I.pl. injection of melittin at half the dosage of WBV strongly reduced mechanical threshold, and increased flinchings and paw thickness to a similar extent as those induced by WBV. Melittin- and WBV-induced flinchings and changes in mechanical threshold were dose- dependent and had a rapid onset. Paw thickness increased maximally about 1 hr after melittin and WBV treatment. Time-courses of nociceptive responses induced by melittin and WBV were very similar. Melittin-induced decreases in mechanical threshold and flinchings were suppressed by i.p., i.t. or i.pl. injection of morphine. I.t. administration of melittin $(6{\mu}g)$ reduced mechanical threshold of peripheral receptive field and induced flinching behaviors, but did not cause any increase in paw thickness. In the electrophysiological study, i.pl. injection of melittin increased discharge rates of dorsal horn neurons only with C fiber inputs from the peripheral receptive field, which were almost completely blocked by topical application of lidocaine to the sciatic nerve. These findings suggest that pain behaviors induced by WBV are mediated by melittin-induced activation of C afferent fiber, that the melittin-induced pain model is a very useful model for the study of pain, and that melittin-induced nociceptive responses are sensitive to the widely used analgesics, morphine.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• 제60권6호
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• pp.322-325
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• 2017

Otalgia consists of primary otalgia associated with disorders of the ear itself and referred otalgia due to disorders of organs that share the same innervation with the ear. Disorders of the oral cavity and laryngopharynx served by the glossopharyngeal and vagus nerves are common causes of referred otalgia. Chest pain from myocardial infarction spreads through the afferent pain pathway, especially through the sympathetic nerves in the cardiac plexus and the phrenic nerve, resulting in a typical chest pain or referred pain in the left upper extremity. However, pain spreading through the vagus nerve can theoretically cause referred otalgia. This association between the heart and ear has not been widely acknowledged, even though a referred otalgia can occasionally be the only symptom of the tragic disease, myocardial infarction, and should be taken seriously. We report a patient who complained of left otalgia as the only symptom of myocardial infarction.