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Normal Mucus Release Requires Both Ca2+‐mediated Exocytosis and cAMP Mediated HCO3‐ Transport
Author(s) -
Yang Ning,
Quinton Paul M
Publication year - 2011
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.25.1_supplement.1065.7
Subject(s) - exocytosis , mucus , chemistry , microbiology and biotechnology , biophysics , secretion , biology , biochemistry , ecology
Mounting evidence indicates that the formation of normal mucus depends critically on the environment into which it is discharged. We applied histology, Ussing chamber pH‐stat assays, and mucus collection methods to examine the links between mucin release and ion transport. In wild type mouse (C57BL/6) small intestine, the Ca 2+ mediated agonist (carbachol) did not stimulate sustained HCO 3 − secretion, but induced mucin exocytosis (histologically) and a short circuit current (Isc) increase (possibly due to Cl − secretion). In contrast, cAMP mediated agonists (vasoactive intestinal peptide, isoproterenol) induced both HCO 3 − secretion and Isc increase, but little, if any, exocytosis. cAMP mediated agonists combined with carbachol discharged more mucus into the luminal perfusate than carbachol alone, but the cAMP enhancing effect was absent without HCO 3 − . In CF (ΔF508/ΔF508) mouse small intestine, neither Ca 2+ nor cAMP mediated agonists induced significant HCO 3 − secretion, Isc increase or significant mucus discharge. These results indicate that normal mucus release requires Ca 2+ mediated exocytosis, possibly Cl − secretion, and apparently post‐exocytotic cAMP‐mediated HCO 3 − secretion to affect normal mucin discharge. Concept : Mucus discharge requires Ca 2+ mediated exocytosis + cAMP mediated HCO 3 − secretion. We thank the CFRI, CF Foundation, NIH‐RO1 HL084042 and Dr. Hui Dong.