Distribution of tight junctions in the primate cochlear lateral wall

Research output: Contribution to journalArticle

Abstract

The blood-labyrinth barrier (BLB) is a major structure that separates the inner ear from the systemic blood circulation. Many drugs cannot access the inner ear because of their inability to cross the BLB. In the cochlea, the BLB is mainly distributed in the lateral wall. However, the ultrastructure of the cochlear lateral wall, including the distribution of tight junctions (TJs), which are its main component, has not been thoroughly examined in primates. This study investigated the distribution of TJs in the cochlear lateral wall of the common marmoset by performing immunohistochemistry for TJ markers and transmission electron microscopy. As previously reported in rodents, TJs were distributed at the lumenal side of stria marginal cells and basal cells. In outer sulcus cells, which are more developed in primates than in rodents, TJs were distributed at the side with the endolymph but not at the side with the spiral ligament, where many capillaries were located. These findings indicate that drugs and small compounds circulating systemically in the blood can easily access outer sulcus cells, but have a limited ability to enter endolymph. No structural differences were detected between species, indicating that the in vivo distribution of drugs in cochlear lateral wall cells, including outer sulcus cells, in primates can be predicted by performing rodent experiments.

Original languageEnglish
Article number134686
JournalNeuroscience Letters
Volume717
DOIs
Publication statusPublished - 2020 Jan 19

Fingerprint

Tight Junctions
Cochlea
Inner Ear
Primates
Endolymph
Rodentia
Spiral Ligament of Cochlea
Pharmaceutical Preparations
Callithrix
Blood Circulation
Transmission Electron Microscopy
Cell Wall
Immunohistochemistry

Keywords

  • Blood-labyrinth barrier
  • Endolymph
  • Marmoset
  • Outer sulcus cell
  • Tight junction

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

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title = "Distribution of tight junctions in the primate cochlear lateral wall",
abstract = "The blood-labyrinth barrier (BLB) is a major structure that separates the inner ear from the systemic blood circulation. Many drugs cannot access the inner ear because of their inability to cross the BLB. In the cochlea, the BLB is mainly distributed in the lateral wall. However, the ultrastructure of the cochlear lateral wall, including the distribution of tight junctions (TJs), which are its main component, has not been thoroughly examined in primates. This study investigated the distribution of TJs in the cochlear lateral wall of the common marmoset by performing immunohistochemistry for TJ markers and transmission electron microscopy. As previously reported in rodents, TJs were distributed at the lumenal side of stria marginal cells and basal cells. In outer sulcus cells, which are more developed in primates than in rodents, TJs were distributed at the side with the endolymph but not at the side with the spiral ligament, where many capillaries were located. These findings indicate that drugs and small compounds circulating systemically in the blood can easily access outer sulcus cells, but have a limited ability to enter endolymph. No structural differences were detected between species, indicating that the in vivo distribution of drugs in cochlear lateral wall cells, including outer sulcus cells, in primates can be predicted by performing rodent experiments.",
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AU - Saeki, Tsubasa

AU - Hosoya, Makoto

AU - Shibata, Shinsuke

AU - Okano, Hideyuki

AU - Fujioka, Masato

AU - Ogawa, Kaoru

PY - 2020/1/19

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