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Cell volume (CV) responses of adherent cells and cell suspensions of guinea‐pig fresh tracheal epithelial cells (EC) to hyperosmolar challenge
Author(s) -
Fedan J S,
Ismailoglu I B,
Dowdy J A,
Roberts J R
Publication year - 2007
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.21.6.a1170
Subject(s) - guinea pig , cell , microbiology and biotechnology , chemistry , biology , biochemistry , endocrinology
In the isolated, perfused trachea contracted with serosally‐applied methacholine (MCh, 3õ10 −7 M), mucosal application of D‐mannitol (D‐M) elicits relaxation mediated by epithelium‐derived relaxing factor (EpDRF), a decrease in the transepithelial (TE) potential difference (V t ), and an increase in TE resistance (R t ). Our previous indirect evidence suggested that EpDRF release is triggered by osmolar jump, rather than osmolar concentration or a decrease in CV. We evaluated D‐M‐induced CV decreases using two direct methods. First, fresh segments of trachea were mounted in a device for simultaneously measuring V t and CV, using calcein(15 μM, 30 min)‐loaded EC and confocal microscopy. Serosal application of MCh increased V t but had little effect on CV (5.2 ± 5.5 %). Mucosal application of D‐M (120–266 mosM) elicited depolarization and a decrease in CV. Second, EC that excluded trypan blue and showed beating cilia were isolated by protease digestion (0.2%, 1 h); CV was measured with a cell sizer. MCh had a negligible effect on CV, whereas D‐M decreased CV concentration‐dependently. Thus, hyperosmolar challenge of EC with D‐M causes cell shrinkage. DISCLAIMER. The findings and conclusions in this abstract have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination of policy. Funding: NIOSH