Cellular localization of facilitated glucose transporter 1 (GLUT-1) in the cochlear stria vascularis: its possible contribution to the transcellular glucose pathway |
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Authors: | Motonori Ando Midori Edamatsu Sho Fukuizumi Shunji Takeuchi |
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Institution: | (1) Laboratory of Cell Physiology, Department of Science Education, Okayama University, Okayama 700-8530, Japan;(2) Department of Otolaryngology, Kagawa Inoshita Hospital, Kanonji 769-1613, Japan |
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Abstract: | Immunoreactivity for the facilitated glucose transporter 1 (GLUT-1) has been found in the cochlear stria vascularis, but whether
the strial marginal cells are immunopositive for GLUT-1 remains uncertain. To determine the cellular localization of GLUT-1
and to clarify the glucose pathway in the stria vascularis of rats and guinea pigs, immunohistochemistry was performed on
sections, dissociated cells, and whole-tissue preparations. Immunoreactivity for GLUT-1 in sections was observed in the basal
side of the strial tissue and in capillaries in both rats and guinea pigs. However, the distribution of the positive signals
within the guinea pig strial tissue was more diffuse than that in rats. Immunostaining of dissociated guinea pig strial cells
revealed GLUT-1 in the basal cells and capillary endothelial cells, but not in the marginal cells. These results indicated
that GLUT-1 was not expressed in the marginal cells, and that another isoform of GLUT was probably expressed in these cells.
Three-dimensional observation of whole-tissue preparations demonstrated that cytoplasmic prolongations from basal cells extended
upward to the apical surface of the stria vascularis from rats and guinea pigs, and that the marginal cells were surrounded
by these protrusions. We speculate that these upward extensions of basal cells have been interpreted as basal infoldings of
marginal cells in previous reports from other groups. The three-dimensional relationship between marginal cells and basal
cells might contribute to the transcellular glucose pathway from perilymph to intrastrial space.
This study was supported by a grant-in-aid for scientific research (19570058) from The Ministry of Education, Culture, Sports,
Science, and Technology of Japan. |
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Keywords: | Inner ear Glucose transporter Marginal cell Basal cell Confocal laser microscopy Rat (Brown Norway) Guinea pig |
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