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DIDS causes Src‐dependent inhibition of Na,K‐ATPase in the ciliary epithelium and slows aqueous humor secretion by the intact porcine eye
Author(s) -
Delamere Nicholas A,
Mandal Amritlal,
Shahidullah Mohammad
Publication year - 2012
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.26.1_supplement.885.7
Subject(s) - dids , chemistry , ouabain , secretion , ciliary processes , ciliary body , biophysics , ion transporter , epithelium , biochemistry , microbiology and biotechnology , biology , membrane , sodium , genetics , organic chemistry , neuroscience
Aqueous humor secretion is the result of net ion transport that involves the coordinated operation of Na,K‐ATPase in the nonpigmented ciliary epithelium (NPE) with several other basolateral transporters and channels in the ciliary epithelium bilayer. Here, we report on the ability of DIDS to reduce aqueous humor secretion and present studies to examine the mechanism. In an intact pig eye preparation the rate of aqueous secretion was significantly reduced by DIDS added to the blood‐side perfusate. In primary cultured NPE, DIDS inhibited ouabain‐sensitive 86Rb uptake and activated Src family kinase (SFK) and ERK1/2 as judged by Western blot analysis. PP2, a SFK inhibitor, prevented the DIDS effect on 86Rb uptake, SFK and ERK1/2. DIDS was found to reduce cytoplasmic pH in BCECF‐loaded NPE. Parallel studies showed PP2 eliminates activation of SFK and ERK1/2 that occurs upon pH reduction. The ability of DIDS to suppress aqueous humor secretion is consistent with inhibition of Na,K‐ATPase in the NPE following a drop in cytoplasmic pH and SFK and ERK1/2 activation. Funding: NIH Grant EY06915