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Immunohistological classification of ionocytes in the external gills of larval Japanese black salamander, Hynobius nigrescens Stejneger
Author(s) -
Uchiyama Minoru,
Kumano Tomoko,
Komiyama Makiko,
Yoshizawa Hideki,
Matsuda Kouhei
Publication year - 2011
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.10977
Subject(s) - gill , biology , salamander , caudata , epithelium , apical membrane , anatomy , larva , metamorphosis , microbiology and biotechnology , zoology , ecology , fishery , fish <actinopterygii> , genetics
In this cytological and immunohistological study, we clarified the localization of the membrane transporters Na + , K + ‐ATPase (NKA), vacuolar‐type H + ‐ATPase (VHA), and epithelial sodium channel (ENaC) and distinguished ionocyte subtypes in the gill of the Japanese salamander ( Hynobius nigrescens ). In larvae (IY stages 43–65), NKA immunoreactivity was observed on the basolateral plasma membrane in more than 60% cells and less than 20% cells in the primary filaments and secondary lamellae of the external gills, respectively. VHA immunoreactivity was observed on the apical membrane of some epithelial cells in the secondary lamellae of the external gills. High ENaCα immunoreactivity was widely observed on the apical cell membrane of a population of squamous cells, presumably pavement cells (PVCs), and mitochondria‐rich cells (MRCs), in the primary filaments and secondary lamellae of the external gills. Using double immunofluorescence microscopy, epithelial cell types involved in ionic regulation were characterized and divided into three ionocyte types: NKA‐, NKA‐ and ENaC‐, and VHA‐positive cells. VHA‐immunoreactive cells as well as NKA‐positive cells were observed during IY stages 43–65 of the salamander larvae. During late stages of metamorphosis, NKA, VHA, and ENaCα immunoreactivities in the external gills decreased and finally disappeared during the completion of metamorphosis (IY stage 68). PVCs and MRCs in the external gills are probably involved in acid–base balance regulation and osmoregulation in urodele amphibian larvae. The results are discussed in relation to the ionocytes previously reported in fish gills and the frog skin epithelium. J. Morphol., 2011. © 2011Wiley‐Liss, Inc.