Mechanism of acid adaptation of a fish living in a ph 3.5 lake

Taku Hirata, Toyoji Kaneko, Toshihiro Ono, Takeru Nakazato, Norihisa Furukawa, Sanae Hasegawa, Shigeo Wakabayashi, Munekazu Shigekawa, Min Hwang Chang, Michael F. Romero, Shigehisa Hirose

Research output: Contribution to journalArticlepeer-review

190 Scopus citations


Despite unfavorable conditions, a single species of fish, Osorezan dace, lives in an extremely acidic lake (pH 3.5) in Osorezan, Aomori, Japan. Physiological studies have established that this fish is able to prevent acidification of its plasma and loss of Na+. Here we show that these abilities are mainly attributable to the chloride cells of the gill, which are arranged in a follicular structure and contain high concentrations of Na+-K+-ATPase, carbonic anhydrase II, type 3 Na+/H+ exchanger (NHE3), type 1 Na+-HCO3- cotransporter, and aquaporin-3, all of which are upregulated on acidification. Immunohistochemistry established their chloride cell localization, with NHE3 at the apical surface and the others localized to the basolateral membrane. These results suggest a mechanism by which Osorezan dace adapts to its acidic environment. Most likely, NHE3 on the apical side excretes H+ in exchange for Na+, whereas the electrogenic type 1 Na+-HCO3- cotransporter in the basolateral membrane provides HCO3- for neutralization of plasma using the driving force generated by Na+-K+-ATPase and carbonic anhydrase II. Increased expression of glutamate dehydrogenase was also observed in various tissues of acid-adapted dace, suggesting a significant role of ammonia and bicarbonate generated by glutamine catabolism.

Original languageEnglish (US)
Pages (from-to)R1199-R1212
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number5 53-5
StatePublished - May 1 2003


  • Aquaporin
  • Carbonic anhydrase
  • Glutamine catabolism
  • Sodium-bicarbonate cotransporter
  • Sodium/proton exchanger

ASJC Scopus subject areas

  • General Medicine


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