Chloride transport in mitochondrion-rich cells of euryhaline tilapia (Oreochromis mossambicus) larvae

Jiun Lin Horng, Pung Pung Hwang, Tin Han Shih, Zhi Hong Wen, Chan Shing Lin, Li Yih Lin

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48 Citations (Scopus)


A noninvasive scanning ion-selective electrode technique (SIET) was applied to measure Cl- transport at individual mitochondrion-rich cells (MRCs) in the skin of euryhaline tilapia (Oreochromis mossambicus) larvae. In seawater (SW)-acclimated larvae, outward Cl- gradients (20-80 mM higher than the background) were measured at the surface, indicating a secretion of Cl- from the skin. By serial probing over the surface of MRCs and adjacent keratinocytes (KCs), a significant outward flux of Cl- was detected at the apical opening (membrane) of MRCs. Treatment with 100 μM ouabain or bumetanide inhibited the Cl- secretion by ∼75%. In freshwater (FW)-acclimated larvae, a lower level of outward Cl- gradients (0.2-1 mM) was measured at the skin surface. Low-Cl- water (<0.005 mM) acclimation increased the apical Na+-Cl- cotransporter (NCC) immunoreactivity of MRCs in the larval skin. An inward flux of Cl- was detected when probing the exterior surface of a group of MRCs (convex-MRCs) that express the NCC. An NCC inhibitor (100 μM metolazone) reduced the flux by ∼90%. This study provides direct and convincing evidence for Cl- transport by MRCs of SW- and FW-acclimated euryhaline tilapia and the involvement of an apical NCC in Cl- uptake of MRCs of FW-acclimated fish.

Original languageEnglish
Pages (from-to)C845-C854
JournalAmerican Journal of Physiology - Cell Physiology
Issue number4
Publication statusPublished - 2009
Externally publishedYes


  • Gills
  • Ionocytes
  • Ionoregulation
  • Na-Cl cotransporter
  • Osmoregulation

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


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