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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2004-11-8
pubmed:abstractText
Submucosal glands are the primary source of airway mucus, a critical component of lung innate defenses. Airway glands are defective in cystic fibrosis (CF), showing a complete absence of secretion to vasoactive intestinal peptide or forskolin, which increase intracellular cAMP concentration. This defect is attributed to gland serous cells, which express the cystic fibrosis transmembrane conductance regulator. Calu-3 cells, which mimic many features of serous cells, secrete Cl(-) and HCO(3)(-), with HCO(3)(-) secretion predominating for forskolin stimulation and Cl(-) secretion predominating for stimuli that open basolateral K(+) channels to hyperpolarize the cells. We used pH stat and ion substitution experiments to clarify the mechanisms and consequences of these two modes of secretion. We confirm that Calu-3 cells secrete primarily HCO(3)(-) in response to forskolin. Unexpectedly, HCO(3)(-) secretion continued in response to K(+) channel openers, with Cl(-) secretion being added to it. Secretion of HCO(3)(-) from hyperpolarized cells occurs via the conversion of CO(2) to HCO(3)(-) and is reduced by approximately 50% with acetazolamide. A gap between the base equivalent current and short-circuit current was observed in all experiments and was traced to secretion of H(+) via a ouabain-sensitive, K(+)-dependent process (possibly H(+)-K(+)-ATPase), which partially neutralized the secreted HCO(3)(-). The conjoint secretion of HCO(3)(-) and H(+) may help explain the puzzling finding that mucus secreted from normal and CF glands has the same acidic pH as does mucus from glands stimulated with forskolin or ACh. It may also help explain how human airway glands produce mucus that is hypotonic.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1040-0605
pubmed:author
pubmed:issnType
Print
pubmed:volume
287
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
L1274-83
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
Acid and base secretion in the Calu-3 model of human serous cells.
pubmed:affiliation
Cystic Fibrosis Research Laboratory, Stanford University, Stanford, CA 94305, USA. mauri@psych.stanford.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't