Cell Cl and transepithelial Na transport in toad urinary bladder

Abstract

Relationships between short-circuit current (Isc), cell Cl and the mechanism(s) of Cl accumulation in toad bladder epithelial cells were investigated. In serosal Cl-free gluconate Ringer, 80% of the cell Cl (measured by x-ray microanalysis) was lost over 30-60 min with an associated decrease in cell water content. concomitantly, Isc fell to 20% of its initial value within 10 min but then recovered to 45% of its initial value despite continued Cl loss. With the reintroduction of Cl, cell Cl and Isc both recovered within 10 min. Serosal SITS (4-acetamido-4'-isothiocyano-stilbene-2,2'-disulfonate; 0.5 mM) plus bumetanide (0.1 mM), did not prevent the fall in Isc or the loss of cell Cl in gluconate medium, although they did inhibit subsequent recovery of Isc in this medium. They also prevented the recovery of Isc in Cl medium but not the reaccumulation of Cl by the cells. Although SITS and bumetanide did not prevent the loss or recovery of Cl, they modified the pattern of the ion changes. In their absence, changes in cellular Cl were twice that of the changes in measured cellular cations implicating basolateral Cl/HCO3 exchange in Cl movement. With SITS plus bumetanide present, changes of similar magnitude in Cl were associated with equivalent changes in cation, consistent with the inhibition of Cl/HCO3 exchange.

Selective Role of Intracellular Chloride in the Regulation of the Intrinsic but Not Extrinsic Pathway of Apoptosis in Jurkat T-cells

“…Furthermore, our studies evaluate the effect of a medium with reduced chloride to modulate the intracellular chloride content during programmed cell death. Chloride-reduced media have been widely used to study volume regulatory mechanisms because cells respond to this environment with a depletion of chloride within minutes (21)(22)(23)(24). In accordance with these reports, we measured a significant decrease in intracellular chloride for cells cultured in RPMI with reduced chloride content.…”

“…intracellular chloride. Furthermore, inhibition of chloride flux by application of the chloride channel inhibitor SITS or intracellular chloride depletion via use of medium with reduced chloride content (21)(22)(23)(24) attenuates UV-C-but not FasL-induced apoptotic characteristics in Jurkat T-cells. Moreover, the activation of the MAP kinase family members JNK and MKK4 following UV-C stimulation was abolished by chloride flux modulation, indicating a specific role of chloride flux in the regulation of signaling cascades.…”

Phagosomal chloride dynamics in the alveolar macrophage

“…This required depletion of intracellular Cl − in AMs before presenting them with cargo for phagocytic uptake. Previous studies focused on Cl − regulation of intracellular processes have evaluated the depletion of intracellular Cl − concentration as a function of a reduction in extracellular Cl − concentration ( Lambert and Lowe, 1978 ) ( Butt et al., 1994 ) ( Takeuchi et al., 1997 ) ( Heimlich and Cidlowski, 2006 ). In our studies, cells were exposed to Cl − -depleted medium for >2 h to ensure maximum intracellular Cl − depletion.…”