Cellular and paracellular resistances of theNecturus proximal tubule

Guggino, William B.; Windhager, Erich E.; Boulpaep, Emile L.; Giebisch, Gerhard

doi:10.1007/bf01868657

Cited by 50 publications

(35 citation statements)

References 18 publications

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“…For TEER measurements, as previously described in detail (13,14,25,32), we used a commercially available electrode chamber (Endohm-24, WPI, Sarasota, FL) that can house an individual filter cup (Fig. 1).…”

Section: Methodsmentioning

confidence: 99%

The electrical resistance breakdown assay determines the role of proteinases in tumor cell invasion

Ludwig¹,

Ossig²,

Graessel

et al. 2002

American Journal of Physiology-Renal Physiology

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The electrical resistance breakdown of the Madin-Darby canine kidney (MDCK) cell monolayer provides a continuous assay system for cancer invasion that detects functional changes before morphological alterations. In this study, we address the question of whether physical contact between tumor cell and epithelial monolayer is a prerequisite for tumor cell invasion. When human melanoma cells were seeded directly (i.e., physical contact) on top of an electrically tight epithelial cell layer (5,800 ± 106 Ω · cm2), electrical monolayer leakage led to an 18 ± 3% reduction of transepithelial electrical resistance within 24 h. However, when melanoma cells were seeded close to the basolateral surface of the epithelial cell monolayer but separated by a filter membrane (i.e., no physical contact), electrical leakage occurred even more quickly (42 ± 3% reduction in 24 h). Atomic force microscopy detected discrete structural changes between cells. Electrical leakage was effectively blocked by α2-macroglobulin or ilomastat, inhibitors of matrix metalloproteinases. We conclude that exocytosis of soluble proteases causes electrical breakdown of the MDCK monolayer, independently of physical contact between tumor cells and the monolayer.

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Section: Methodsmentioning

confidence: 99%

The electrical resistance breakdown assay determines the role of proteinases in tumor cell invasion

Ludwig¹,

Ossig²,

Graessel

et al. 2002

American Journal of Physiology-Renal Physiology

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“…The distance between current electrode and potential-recording electrode was measured with an ocular micrometer. From these measurements the length constant k~u and Rte can be determined as described in detail previously [2,3,6,13].…”

Section: Resistance Measurementsmentioning

confidence: 99%

Resistance properties of the diluting segment ofAmphiuma kidney: Influence of potassium adaptation

1985

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Chronic exposure to high potassium stimulates K+-secretory mechanisms in the diluting segment of the amphibian kidney (K+ adaptation). Since K+ net flux depends critically on the passive cell membrane permeabilities for K+ ions, cable analysis and K+-concentration step changes were applied in this nephron segment to assess the individual resistances of the epithelium and the K+ conductance of the luminal cell membrane. Experiments were performed in the isolated, doubly-perfused kidney of both control and K+-adapted Amphiuma. In control animals transepithelial resistance was 290 +/- 27 omega cm2, which decreased significantly to 199 +/- 17 omega cm2 after K+ adaptation. The resistance in parallel of the luminal and peritubular cell membrane decreased from a control value of 157 +/- 14 to 108 +/- 6 omega cm2 after chronic K+ treatment. This was paralleled by a decrease of the ratio of the luminal to peritubular cell membrane resistance from 2.5 +/- 0.1 to 1.9 +/- 0.1, respectively. Estimation of the individual cell membrane resistances reveals that the combined resistance of the luminal and peritubular cell membrane is in the same order of magnitude as the paracellular shunt resistance in diluting segments of both control and K+-adapted animals. The luminal cell membrane is K+ selective under both conditions, but the absolute luminal K+ conductance increases by some 60% with K+ adaptation. This leads to an increased back-leak of K+ from cell to lumen and may explain stimulated K+ net secretion found after chronic K+ loading.

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“…The surface of junctional network per unit area of epithelium is very small relative to that of the cell membranes (Spring, 1991). However, the high ionic permeability of the junctions in this class of epithelia (Frrmter, 1972;Guggino, Windhager, Boulpaep, and Giebisch, 1982) suggests the possibility that their osmotic water permeability is also high, and hence junctional osmotic water flow cannot be ruled out a priori.…”

Section: Introductionmentioning

confidence: 98%

“…Therefore, these observations correspond to apparent streaming potentials, which in principle could be explained by coupling between water and ion fluxes in an ion-selective pathway (true streaming potential) or by a salt concentration gradient produced across the epithelium because of the water flow elicited by the osmotic gradient. Regardless of which of these mechanisms is responsible for the observed voltage changes, it is likely that the site of production of the apparent streaming potential is paracellular, because in gallbladder epithelium and in renal proximal tubules the paracellular ion conductance is much higher than the ion conductances of the cell membranes (Frrmter, 1972;Reuss and Finn, 1975a, b;Guggino et al, 1982;Stoddard and Reuss, 1988a). However, definitive conclusions on the site of origin of the apparent streaming potential require measurements of cell membrane voltages and conductances.…”

Section: General Characteristics Of Apparent Streaming Potentials In mentioning

confidence: 99%

Pseudo-streaming potentials in Necturus gallbladder epithelium. I. Paracellular origin of the transepithelial voltage changes.

Reuss

Simon

1992

The Journal of General Physiology

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A B S T g A C T Apparent streaming potentials were elicited across Necturus gallbladder epithelium by addition or removal of sucrose from the apical bathing solution. In NaCl Ringer's solution, the transepithelial voltage (I'm,) change (reference, basolateral solution) was positive with sucrose addition and negative with sucrose removal. Bilateral CI-removal (cyclamate replacement) had no effect on the polarity or magnitude of the Vm, change elicited by addition of 100 mM sucrose. In contrast, bilateral Na + removal (tetramethylammonium [TMA +] replacement) inverted the Vm~ change (from 2.7 +-0.3 to -3.2 _+ 0.2 mV). Replacement of Na ÷ and C1-with TMA ÷ and cyclamate, respectively, abolished the change in V~,. Measurements of cell membrane voltages and relative resistances during osmotic challenges indicate that changes in cell membrane parameters do not explain the transepithelial voltage changes. The initial changes in Vm, were slower than expected from concomitant estimates of the time course of sucrose concentration (and hence osmolality) at the membrane surface. Paired recordings of the time courses of paracellular bi-ionic potentials (partial substitution of apical Na ÷ with tetrabutylammonium [TBA*]) revealed much faster time courses than those produced by sucrose addition, although the diffusion coefficients of sucrose and TBACI are similar. Hyperosmotic and hypoosmotic challenges yielded initial Vm, changes at the same rate; thereafter, the voltage increased with hypoosmotic solution and decreased with hyperosmotic solution. These late voltage changes appear to result from changes in width of the lateral intercellular spaces. The early time courses of the I'm, changes produced by osmotic challenge are inconsistent with the expectations for water-ion flux coupling in the junctions. We propose that they are pseudo-streaming potentials, i.e., junctional diffusion potentials caused by salt concentration changes in the lateral intercellular spaces secondary to osmotic water flow.

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Cellular and paracellular resistances of theNecturus proximal tubule

Cited by 50 publications

References 18 publications

The electrical resistance breakdown assay determines the role of proteinases in tumor cell invasion

The electrical resistance breakdown assay determines the role of proteinases in tumor cell invasion

Resistance properties of the diluting segment ofAmphiuma kidney: Influence of potassium adaptation

Pseudo-streaming potentials in Necturus gallbladder epithelium. I. Paracellular origin of the transepithelial voltage changes.

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