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Expression of Cl/HCO3 Exchanger AE2 and Na‐K‐2Cl Cotransporter NKCC1 in Amphibian Stomach
Author(s) -
Talbot Colleen,
Ballesteros Jessica,
Kindervater Ryan,
Lytle Christian
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1239.20
Subject(s) - cotransporter , secretion , mucus , gastric glands , amphibian , antrum , biology , epithelial polarity , epithelium , rana , chemistry , stomach , microbiology and biotechnology , anatomy , endocrinology , gastric mucosa , sodium , biochemistry , ecology , genetics , organic chemistry
The gastric mucosa secretes Cl − with or without H + (acidic and nonacidic Cl − secretion) by macroscopically electroneutral and electrogenic processes, respectively, that utilize 2 mechanisms for basolateral Cl − uptake: Cl/HCO 3 exchange via AE2 and Na‐K‐2Cl cotransport via NKCC1. The relative contribution these transporters to acidic and nonacidic Cl − secretion and the anatomical origin of these secretions in different animal models remains unclear. We localized AE2 and NKCC1 proteins in the corpus and antrum of the anuran frog Rana catesbeiana and urodele salamanders Necturus maculosus and Ambystoma spp by quantitative confocal immunofluorescence microscopy. In the salamanders, basolateral labeling of AE2 and NKCC1 was exceptionally prominent in mucus cells at the base of antral glands and in oxyntopeptic cells in gastric glands throughout the corpus. In the frog, mucus cells in the antral gland base likewise contained abundant AE2 and NKCC1, whereas oxyntopeptic cells contained high levels of only AE2. Our results support the concept that antral gland base cells contribute importantly to nonacidic Cl − secretion and suggest that this process in amphibians, but not in rodents, involves AE2 in addition to NKCC1. Our data reconcile previous functional evidence that in the frog, in contrast to urodele amphibians and rodents, NKCC1 plays a minor role in gastric Cl − secretion. Supported by NIH GM076981 .