Cl− Influx into Rat Cortical Lens Fiber Cells Is Mediated by a Cl− Conductance That Is Not ClC-2 or -3

Webb, Kevin F.; Merriman-Smith, B. Rachelle; Stobie, Jonelle K.; Kistler, Joerg; Donaldson, Paul J.

Abstract

PURPOSE. Exposure of organ-cultured lenses to C1- channel blockers under isotonic conditions induces a localized cortical zone of extracellular space dilations. The purpose of this study was to investigate whether elongated lens fiber cells from this zone contain an anion conductance that mediates CF influx and whether two chloride channel isoforms known to be expressed in the lens (C1C-2 and -3) are responsible.

METHODS. Fiber cells were isolated by enzymatic dissociation in the presence of Gd3+ and Co2+ and their electrical properties analyzed by whole-cell patch clamping. Cells from the zone of extracellular space dilations were selected for analysis on the basis of cell length. RT-PCR and immunocytochemistry were used to determine whether C1C-2 or -3 channel isoforms are expressed in fiber cells located in the zone of extracellular space dilations.

RESULTS. Cells from the zone of extracellular space dilations were typically >120 μm in length and exhibited an outwardly rectifying CF conductance that was blocked by DIDS (4,4′-diisothiocyanostilbene-2,2′-disulfonic acid) and displayed an anion selectivity sequence of I- > C1- ≫ gluconate. C1C-2 and -3 were found to be expressed at the transcript and protein level in lens fiber cells, but subsequent immunocytochemical studies indicated that expressed proteins did not colocalize with cell membranes in the zone of extracellular space dilations, being predominately cytoplasmic in nature.

CONCLUSIONS. Taken together, the data indicate that extracellular space dilations are due to the inhibition of a C1- channel(s) that normally mediates CF influx into cortical lens fiber cells under isotonic conditions. The molecular identity of this channel remains to be determined.

Citation

Webb, K. F., Merriman-Smith, B. R., Stobie, J. K., Kistler, J., & Donaldson, P. J. (2004). Cl− Influx into Rat Cortical Lens Fiber Cells Is Mediated by a Cl− Conductance That Is Not ClC-2 or -3. Investigative Ophthalmology & Visual Science, 45(12), 4400-4408. https://doi.org/10.1167/iovs.04-0205

• Journal Article Type: Article
• Publication Date: 2004-12
• Deposit Date: Apr 20, 2024
• Print ISSN: 0146-0404
• Electronic ISSN: 1552-5783
• Publisher: Association for Research in Vision and Ophthalmology
• Peer Reviewed: Peer Reviewed
• Volume: 45
• Issue: 12
• Pages: 4400-4408
• DOI: https://doi.org/10.1167/iovs.04-0205
• Public URL: https://nottingham-repository.worktribe.com/output/4831789
• Publisher URL: https://iovs.arvojournals.org/article.aspx?articleid=2163165