• The Korean Journal of Zoology
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• v.39 no.1
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• pp.54-64
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• 1996

Normal development of the olfactory placode was studied to describe the sequence of events involved in the development of the olfactory placode. It has been primarily concerned with the morphological differentiation of the sensory neurons, their initial growth, maturation patterns and the contacts of their axons with the primitive prosencephalic vesicle. The olfactory organ first appears at stage 23 as a paired thickening of the two ectodermal layers: the superficial non-nervous layer (NNL) and the inner nervous layer (NL). Receptor cells differentiate from the NL and the supporting cells develop from the NNL. After stage 26 the placodal cells begin to migrate toward the epithelial surface between the NNL cells and their apical processes reach the surface at stage 28. As the apical process reaches the epithelial surface, basal processes (presumptive axons) sprout from the base of the NL cells at stage 29/30. They penetrate the underlying telencephalon by stage 32. Sensory synaptic contacts first appear at stage 37/38. Some placodal cells remain at the olfactory epithelium as basal cells while other placodal cells differentiate into olfactory neurons. The results confirmed that neurons originate exclusively from the nervous layer of the ectoderm while supporting cells originate from the NNL layer. The results also indicate that the development of olfactory neuron is independent of information from the target ftssue.

• Korean Journal of Ichthyology
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• v.34 no.3
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• pp.153-159
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• 2022

The olfactory organ of a Korean endemic species, Pseudobagrus koreanus, was investigated to describe its morphology and histology and analyze correlation between habitat environment and its ecological habits and characters, using a stereo microscope, a light microscope, and a scanning electron microscope. Its external morphology showed tubular anterior nostril at the tip of the snout and slit posterior nostril at the base of the nasal barbel. The olfactory chamber showed the rosette structure consisting of numerous lamellae radial and parallel to the medium raphe. The olfactory lamella has the sensory epithelium with olfactory receptor nuerons, supporting cells, basal cells, lymphatic cells, plasma cells and the non-sensory epithelium with stratified epithelial cells, mucous cells, lymphatic cells. In particular, 1) 41~43 (n=20) lamellae, 2) lymphatic cells and plasma cells, 3) mucous cells including neutral polysaccharid may be olfactory characteristics relevant to a stagnant or a standing habitat environment, nocturnal habit dependent on olfaction, and taxonomic characters compared at least to other catfish species.

• Biomolecules & Therapeutics
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• v.20 no.6
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• pp.506-512
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• 2012

Although pruritus is the critical symptom of atopic dermatitis that profoundly affect the patients' quality of life, controlling and management of prurirtus still remains as unmet needs mainly due to the distinctive multifactorial pathogenesis of pruritus in atopic dermatitis. Based on the distinct feature of atopic dermatitis that psychological state of patients substantially influence on the intensity of pruritus, various psychotropic drugs have been used in clinic to relieve pruritus of atopic dermatitis patients. Only several psychotropic drugs were reported to show real antipruritic effects in atopic dermatitis patients including naltrexone, doxepin, trimipramine, bupropion, tandospirone, paroxetine and fluvoxamine. However, the precise mechanisms of antipruritic effect of these psychotropic drugs are still unclear. In human skin, serotonin receptors and serotonin transporter protein are expressed on skin cells such as keratinocytes, melanocytes, dermal fibroblasts, mast cells, T cells, natural killer cells, langerhans cells, and sensory nerve endings. It is noteworthy that serotonergic drugs, as well as serotonin itself, showed immune-modulating effect. Fenfluramine, fluoxetine and 2, 5-dimethoxy-4-iodoamphetamine significantly decreased lymphocyte proliferation. It is still questionable whether these serotonergic drugs exert the immunosuppressive effects via serotonin receptor or serotonin transporter. All these clinical and experimental reports suggest the possibility that antipruritic effects of selective serotonin reuptake inhibitors in atopic dermatitis patients might be at least partly due to their suppressive effect on T cells. Further studies should be conducted to elucidate the precise mechanism of neuroimmunological interaction in pruritus of atopic dermatitis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.3
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• pp.158-163
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• 2005

This paper deals with the histology of the barbels of striped sea catfish, Plotosus lineatus (Thunberg). This fish have eight noticeable barbels of two pairs on their maxillary and mandibular. Each barbel is composed of an epidermis, dermis and a central rod of cartilage. The epidermis in the middle part of the maxillary barbel is thicker than those on other parts, and formed of stratified epithelium which contains many cutaneous taste buds and a few small club cells. Number of taste buds increase on the middle and posterior part of each barbel. The dermis consists of loose connective tissue fibers which encloses blood vessels and bundles of nerve fibers. The barbels of this fish can be categorized into stiff and flexible types and are accessory, feeding and sensory structures. Thus we substantiate that they are gustatory receptor organs for this fish.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.14-23
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• 2002

Development of oligodendrocytes and the generation of myelin internodes within the spinal cord depends on regional signals derived from the notochord and axonally derived signals. Neuregulin (NRG)-1, localized in the floor plate as well as in motor and sensory neurons, is necessary for normal oligodendrocyte development. Oligodendrocytes respond to NRGs by activating members of the erbB receptor tyrosine kinase family. Here, we show that erbB2 is not necessary for the early stages of oligodendrocyte precursor development, but is essential for proligodendroblasts to differentiate into galactosylcerebroside-positive (GalC+) oligodendrocytes. In the presence of erbB2, oligodendrocyte development is normal. In the absence of erbB2 (erbB2-/-), however, oligodendrocyte development is halted at the proligodendroblast stage with a >10-fold reduction in the number of GalC+ oligodendrocytes. ErbB2 appears to function in the transition of proligodendroblast to oligodendrocyte by transducing a terminal differentiation signal, since there is no evidence of increased oligodendrocyte death in the absence of erbB2. Furthermore, known survival signals for oligodendrocytes increase oligodendrocyte numbers in the presence of erbB2, but fail to do so in the absence of erbB2. Of the erbB2-/- oligodendrocytes that do differentiate, all fail to ensheath neurites. These data suggest that erbB2 is required for the terminal differentiation of oligodendrocytes and for development of myelin.

• International Journal of Oral Biology
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• v.31 no.4
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• pp.135-140
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• 2006

Temperature signaling can be initiated by members of transient receptor potential (thermo-TRP) channels. Hot and cold substances applied to teeth usually elicit pain sensation. Since odontoblasts constitute a well-defined layer between the pulp and the mineralized dentin, being first to encounter thermal stimulation from oral cavity, they may be involved in sensory transduction process, in addition to their primary function as formation of dentin. We investigated whether thermo-TRP channels are expressed in a odontoblast cell line, MDPC-23. The expressions of thermo-TRP channels were examined using reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, fluorometric calcium imaging. Analysis of RT-PCR revealed mRNA expression of TRPV1, TRPV2, TRPV4 and TRPM8, but no TRPV3, TRPA1. Immunohistochemical approach failed to detect TRPV1 expression. Whereas the application of 4-phorbol-12,13-didecanoate($10\;{\mu}M$, a TRPV4 agonist), menthol(1 mM, a TRPM8 agonist) and icilin($10\;{\mu}M$, a TRPM8 agonist) produced the enhancement of intracellular calcium concentration, capsaicin($1\;{\mu}M$, a TRPV1 agonist) did not. Our results suggest that subfamily of thermo-TRP channels expressed in odontoblasts may serve as thermal or mechanical transducer in teeth.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.3
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• pp.211-217
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• 2012

Recent studies have demonstrated that nitric oxide (NO) activates transient receptor potential vanilloid subtype 1 (TRPV1) via S-nitrosylation of the channel protein. NO also modulates various cellular functions via activation of the soluble guanylyl cyclase (sGC)/protein kinase G (PKG) pathway and the direct modification of proteins. Thus, in the present study, we investigated whether NO could indirectly modulate the activity of TRPV1 via a cGMP/PKG-dependent pathway in cultured rat dorsal root ganglion (DRG) neurons. NO donors, sodium nitroprusside (SNP) and S-nitro-N-acetylpenicillamine (SNAP), decreased capsaicin-evoked currents ($I_{cap}$). NO scavengers, hemoglobin and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO), prevented the inhibitory effect of SNP on $I_{cap}$. Membrane-permeable cGMP analogs, 8-bromoguanosine 3', 5'-cyclic monophosphate (8bromo-cGMP) and 8-(4chlorophenylthio)-guanosine 3',5'-cyclic monophosphate (8-pCPT-cGMP), and the guanylyl cyclase stimulator YC-1 mimicked the effect of SNP on $I_{cap}$. The PKG inhibitor KT5823 prevented the inhibition of $I_{cap}$ by SNP. These results suggest that NO can downregulate the function of TRPV1 through activation of the cGMP/PKG pathway in peripheral sensory neurons.

• Biomolecules & Therapeutics
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• v.30 no.1
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• pp.38-47
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• 2022

The present study focused on lithocholic acid (LCA), a secondary bile acid that contributes to cholestatic pruritus. Although recent studies have found that LCA acts on MAS-related G protein-coupled receptor family member X4 (MRGPRX4) in humans, it is unclear which subtypes of MRGPRs are activated by LCA in mice since there is no precise ortholog of human MRGPRX4 in the mouse genome. Using calcium imaging, we found that LCA could activate mouse Mrgpra1 when transiently expressed in HEK293T cells. Moreover, LCA similarly activates mouse Mrgprb2. Importantly, LCA-induced responses showed dose-dependent effects through Mrgpra1 and Mrgprb2. Moreover, treatment with QWF (an antagonist of Mrgpra1 and Mrgprb2), YM254890 (Gα_q inhibitor), and U73122 (an inhibitor of phospholipase C) significantly suppressed the LCA-induced responses, implying that the LCA-induced responses are indeed mediated by Mrgpra1 and Mrgprb2. Furthermore, LCA activated primary cultures of mouse sensory neurons and peritoneal mast cells, suggesting that Mrgpra1 and Mrgprb2 contribute to LCA-induced pruritus. However, acute injection of LCA did not induce noticeable differences in scratching behavior, implying that the pruritogenic role of LCA may be marginal in non-cholestatic conditions. In summary, the present study identified for the first time that LCA can activate Mrgpra1 and Mrgprb2. The current findings provide further insight into the similarities and differences between human and mouse MRGPR families, paving a way to understand the complex roles of these pruriceptors.

• Journal of Korean Medical Ki-Gong Academy
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• v.22 no.1
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• pp.1-27
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• 2023

Objective : This paper provides a narrative review of the research literature on the neurophysiological and neurochemical mechanisms of local vibration while studying the treatment principles and mechanisms of Whidam's vibrator Sugi therapy. Methods : Searches related to vibration therapy research were conducted in PUBMED using "Vibration", "Whole Body Vibration", "Localized Vibration", and "Focal Vibration". The Conditions were limited to review and systematic review. Results : Roberto Casale's paper was selected as an inquiry task and reviewed critically and narratively by referring to other papers. The stimulation process of local vibration (LV) was broadly classified into receptor transmission (pain reception phase), ascending sensory pathway to the spinal cord (segmental phase), and action of the cortex and subcortical structures (systemic control phase) according to the pain pathway. In addition, the role of C-tactile mechanoreceptors, changes in neurotransmitters and neurohormones, LV stimulation below perception threshold (lower threshold), pain control and kinesiologic illusions were specially addressed. In addition, the expression and function of Piezo Channels were added to supplement the human pain and tactile sensing mechanism. Conclusions : LV exerts pain control mechanisms through different interactions that can interfere with pain transmission and pain perception. Since LV provides sufficient neurophysiological reasons for clinical application, it is necessary to expand the use of Whidam's vibrator Sugi therapy to a wider range of clinical applications.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.1-7
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• 2021

Using stereo, light, and scanning electron microscopes, we researched the anatomical and histological structure of Chaenogobius gulosus's olfactory organ and compared it to those of sympatric gobies Luciogobius guttatus and Favonigobius gymnauchen. Results revealed the following common characteristics: i) tubular anterior nostril (AN) and flat posterior nostril (PN), ii) a single longitudinal lamella, iii) two accessory nasal sacs (ANS, ethmoidal and lacrimal), iv) abundant sensory epithelium lymphatic cells (LC), v) an eosinophil cell, and vi) a ciliary length a quarter of the knob diameter in the olfactory receptor neuron (ORN). Some characteristics are specific to C. gulosus and different from the other two gobies: i) 0.5~1.0 mm AN and 0.2~0.5 mm PN (vs. 0.2~0.3 mm and 0.2~0.3 mm in L. guttatus; 0.2~0.4 mm and 0.1~0.3 mm in F. gymnauchen), ii) two ANS (vs. absence in L. guttatus; two in F. gymnauchen), iii) abundant LC (vs. low in L. guttatus and F. gymnauchen), iv) low density non-sensory cilia on the lamellar surface (vs. high in L. guttatus; low in F. gymnauchen), and v) a quarter ciliary length to knob diameter ratio in the ORN (vs. mixture of a quarter to equal ratio in L. guttatus; two or three times in F. gymnauchen). From these results, we confirmed the C. gulosus olfactory organ has adapted anatomically and histologically to the sand-rock tidal zone.