Figure 6 of Chee, Mol Vis 2010; 16:800-812.


Figure 6. Modulation of ion transport pathways has specific effects on fiber cell morphology in the rat lens cortex. Schematic diagrams summarizing the distinctly different damage phenotypes induced in the outer cortex of rat lenses organ cultured in the presence of modulators of cation chloride cotransporters and Cl channels for 18 h. A: The NKCC inhibitor bumetanide (2 μM) caused peripheral cell shrinkage and extracellular space dilations in the deeper influx zone. B: The Cl- channel inhibitor NPPB (10 μM) had no effect on peripheral fiber cells at this concentration, but did induce extracellular space dilations between deeper fiber cells. C: The KCC inhibitor DIOA (10 μM) caused peripheral cell swelling and deeper extracellular space dilations. D: The KCC activator NEM (1 mM) caused shrinkage of peripheral fiber cells but swelling of deeper fiber cells in the influx zone. E: The observed spatially distinct damage phenotypes can be explained by differential changes in the electrochemical ion gradients for Cl- (ECl) and Na+ (ENa) that occur with radial distance into the lens [40] and their effects on the direction of ion flux mediated by transporters in the two regions of the lens. In peripheral fiber cells outwardly directed Cl- gradients favor Cl- efflux mediated predominately by KCC [11], while in deeper fiber cells the lower transmembrane potential results in a shift in ECl that favors influx mediated by KCC and Cl- channels located in this zone of the lens. In contrast ENa is expected to favor ion influx throughout the entire lens cortex.