| Project/Area Number |
10640656
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生物形態・構造
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| Research Institution | Teikyo University |
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Principal Investigator |
NAGAI Takatsohi TEIKYO UNIVERSITY SCHOOL OF MEDICINE, DEPARTMENT OF PHYSIOLOGY, LECTURER, 医学部, 講師 (50130026)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI Hiroaki SHIZUOKA UNIVERSITY, FACULTY OF SCIENCE, ASSOCIATE PROFESSOR, 理学部, 助教授 (90216854)
KOYAMA Hiromichi YOKOHAMA CITY UNIVERSITY, COLLEGE OF NURSING, ASSOCIATE PROFESSOR, 看護短期大学部, 助教授 (00170407)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2000: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | toad / skin epithelium / chemoreception / sodium channel / fluorescent dye / electron microscope / antibody / spinal nerve / カエル / カーリウムチャネル / アミロライド |
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| Research Abstract |
Our previous project showed chemosensory function of the ventral skin in desert toads (Bufo alvarius) by combined approaches in behavior, physiology and anatomy. We reported putative chemosensory cells in the toad skin. In the present project we extended anatomical approaches to associate the structure of chemosensory cells with proposed sensory transduction in the skin. Those cells labeled with fluorescencent dye were photoconverted in the presence of DAB for electron microscopic examination. Cytological features of the cells were neither reminiscent of Merkel cells and flask cells, but rather similar to those of surrounding non-specialized epithelial cells. Such cells were distributed in the germinativum and spinosum layers, but none of them were seen in the outermost layer of living cells, i.e., the granulosum layer. Some of those cells had close contact with spinal nerve endings. However, synapses were not revealed in the contact area because of limited quality in the present fixat
… More
ion protocol for electron microscopy. These findings suggest that stimulants such as Na^+ ions need to flow through epithelial cell layers to putative chemosensory cells and/or nerve endings to induce neural excitation. The antibody was generated against peptide of alpha subunit of epithelial Na^+ channels (ENaC) in renal tissues of Xenopus. The antibody reacted positively to the apical cell membrane of granulosum cells. Therefore, Na^+ ions possibly flow into the cell through ENaC in the membrane and are pumped out through the basal membrane. Previous physiological experiments showed that the spinal nerve responses were reduced by amiloride, a specific blocker for ENaC. However, the reduction was only partial. Residual neural responses were probably mediated by the ions passing through intercellular spaces in the granulosum layer, because the spinal nerve responses were also reduced by lanthanum and because occulusion of the intercellular spaces with precipitates of lanthanum was revealed by subsequent histological examination. Less
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