Capacitative transients in voltage-clamped epithelia

García-Díaz, J. Fernando; Essig, Alvin

doi:10.1016/s0006-3495(85)83807-8

Cited by 9 publications

(9 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, estimates of intracellular CI activities (Nagel, Garcla-Diaz, and Armstrong, 1981;Gir~tldez and Ferreira, 1984) indicate that for a CI current the reversal should occur at a V v some 38 mV more positive than Vc. Although the actual values of Vc for these experiments were not measured, they are likely to be near the observed reversal potentials (Garcia-Diaz et al, 1985), suggesting that K is the major ion crossing this channel.…”

Section: Single Channel Currentsmentioning

confidence: 84%

“…These structural observations, together with the demonstration of the syncytial behavior of the epithelium (Rick et al, 1978) and the large capacitance of the basolateral membrane of the intact epithelium (Smith, 1971 ;Garcia-Dfaz and Essig, 1985;Schoen and Erlij, 1985) indicates that, functionally, all innermost cell membranes behave as basolateral membrane. This implies that the majority of isolated cells will exhibit macroscopic properties that correspond to the basolateral membrane of the intact epithelium and there would be a much higher probability of recording single channels of basolateral origin/ One can also make the argument that, since the apical membrane of R. pipiens skin does not exhibit any significant conductive permeability to ions other than Na (Helman and Fisher, 1977;Nagel, 1977;Garcia-Diaz et al, 1985;Stoddard, Jakobsson, and Helman, 1985;D6rge, Beck, Wienecke, and Rick, 1989) the K and CI selective channels found in this study are necessarily of basolateral origin.…”

Section: Origin Of K and CL Channelsmentioning

confidence: 99%

“…This conductance is not involved in the transepithelial absorption of C1 that takes place in the frog skin in vivo or in vitro under open circuit conditions. Movement of CI does not occur through the Natransporting principal cells of the epithelium (Garcia-Diaz et al, 1985;D6rge et al, 1989) but seems to be localized either in the mitochondria-rich cells (Vo~te and Meier, 1978;Foskett and Ussing, 1986;Larsen et al, 1987) or in the tight junctions between Stratum granulosum cells (Nagel, 1989;Nagel and D6rge, 1990). …”

Section: Currents"mentioning

confidence: 99%

See 2 more Smart Citations

Whole-cell and single channel K+ and Cl- currents in epithelial cells of frog skin.

1991

The Journal of General Physiology

View full text Add to dashboard Cite

A B S T R A C T Whole-cell and single channel currents were studied in cells from frog (R. pipiens and R. catesbiana) skin epithelium, isolated by collagenase and trypsin treatment, and kept in primary cultures up to three days. Whole-cell currents did not exhibit any significant time-dependent kinetics under any ionic conditions used. With an external K gluconate Ringer solution the currents showed slight inward rectification with a reversal potential near zero and an average conductance of 5 nS at reversal. Ionic substitution of the external medium showed that most of the cell conductance was due to K and that very little, if any, Na conductance was present. This confirmed that most cells originate from inner epithelial layers and contain membranes with basolateral properties. At voltages more positive than 20 mV outward currents were larger with K in the medium than with Na or N-methyl-Dglucamine. Such behavior is indicative of a multi-ion transport mechanism. Wholecell K current was inhibited by external Ba and quinidine. Blockade by Ba was strongly voltage dependent, while that by quinidine was not. In the presence of high external CI, a component of outward current that was inhibited by the anion channel blocker diphenylamine-2-carboxylate (DPC) appeared in 70% of the cells. This component was strongly outwardly rectifying and reversed at a potential expected for a C1 current. At the single channel level the event most frequently observed in the cell-attached configuration was a K channel with the following characteristics: inward-rectifying I-V relation with a conductance (with 112.

show abstract

Section: Single Channel Currentsmentioning

confidence: 84%

Section: Origin Of K and CL Channelsmentioning

confidence: 99%

Section: Currents"mentioning

confidence: 99%

See 1 more Smart Citation

Whole-cell and single channel K+ and Cl- currents in epithelial cells of frog skin.

1991

The Journal of General Physiology

View full text Add to dashboard Cite

show abstract

“…By averaged 33 msec so that by 100 msec (3 • r) capacitative transients are essentially (95%) dissipated. Employing a similar approach, Garcia-Diaz and Essig (1985) have found that r is approximately 50 msec for Necturus gallbladder cells.…”

Section: Discussionmentioning

confidence: 99%

“…polarization) take place. This was accomplished as follows: Assuming that, to a first approximation, the transcellular pathway can be represented by two linear resistancecapacitance (RC) circuits arranged in series, then when a current pulse is passed across the tissue sufficient to clamp ~jms from zero to a new value (Sqjms) (within 2 msec) ~mc will change with a time course given by DeLong & Civan, 1984;Garcia-Diaz & Essig, 1985) Thus, at t = 0, f(t) is equal to f~ (i.e., the fractional capacitance of the basolateral membrane) and when t = ~, f(t) = f,. (i.e., the fractional resistance of the apical membrane).…”

Section: Capacitative Transients: Determination Of the Fractional Capmentioning

confidence: 99%

Current-voltage relations of sodium-coupled sugar transport across the apical membrane ofNecturus small intestine

Lapointe¹,

Hudson²,

Schultz³

1986

J. Membrain Biol.

View full text Add to dashboard Cite

The current-voltage (I-V) relations of the rheogenic Na-sugar cotransport mechanism at the apical membrane of Necturus small intestine were determined from the relations between the electrical potential difference across the apical membrane, psi mc, and that across the entire epithelium, psi ms, when the latter was varied over the range +/- 200 mV, under steady conditions in the presence of galactose and after the current across the apical membrane carried by the cotransporter, ImSNa, is blocked by the addition of phloridzin to the mucosal solution. ImSNa was found to be strongly dependent upon psi mc over the range -50 mV less than psi mc less than EmSNa where EmSNa is the "zero current" or "reversal" potential. Over the range of values of psi mc encountered under physiological conditions the cotransporter may be modeled as a conductance in series with an electromotive force so that ImSNa = gmSNa (EmSNa - psi mc) where gmSNa is the contribution of this mechanism to the conductance of the apical membrane and is "near constant." In several instances ImSNa "saturated" at large hyperpolarizing or depolarizing values of psi mc. The values of EmSNa determined in the presence of 1, 5, and 15 mM galactose strongly suggest that if the Na-galactose cotransporters are kinetically homogeneous, the stoichiometry of this coupled process is unity. Finally, the shapes of the observed I-V relations are consistent with the predictions of a simple kinetic model which conforms with current notions regarding the mechanico-kinetic properties of this cotransport process.

show abstract

The Use of Ion-Selective Microelectrodes to Study Cellular Transport Processes

García-Díaz

Giráldez

1991

Cell Membrane Transport

View full text Add to dashboard Cite

Capacitative transients in voltage-clamped epithelia

Cited by 9 publications

References 13 publications

Whole-cell and single channel K+ and Cl- currents in epithelial cells of frog skin.

Whole-cell and single channel K+ and Cl- currents in epithelial cells of frog skin.

Current-voltage relations of sodium-coupled sugar transport across the apical membrane ofNecturus small intestine

The Use of Ion-Selective Microelectrodes to Study Cellular Transport Processes

Contact Info

Product

Resources

About