Regulatory Role of Intracellular Calcium Ions in Epithelial Na Transport

Windhager, Erich E.; Taylor, Ann

doi:10.1146/annurev.ph.45.030183.002511

Cited by 78 publications

(33 citation statements)

References 29 publications

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“…In these studies, using fluorescent dyes to measure Ca2+, the high transient levels of Ca2+ ranged from 200 to -500 nM. Despite this information on the behavior of intracellular calcium there are numerous reports (see reference 23 for review) that suggest that chronic increases in Ca4+ down-regulate apical sodium channels and reduce transepithelial movement of sodium in epithelial cells, in contrast to the rise in electrogenic sodium transport found in this study. Because the design of those studies involved chronic sustained elevations of Ca4+ after addition ofcalcium ionophores in concentrations of 1 ,uM or more to the outside bathing solution, it was of interest to determine the effect of ionophores in various doses on Ca2+ and the effect ofchronic elevations ofCa2+ on basal and stimulated electrogenic sodium transport in cultured A6 cells.…”

Section: Discussioncontrasting

confidence: 66%

Correlates of aldosterone-induced increases in Cai2+ and Isc suggest that Cai2+ is the second messenger for stimulation of apical membrane conductance.

Petzel

Ganz²,

Nestler³

et al. 1992

J. Clin. Invest.

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Section: Discussioncontrasting

confidence: 66%

Correlates of aldosterone-induced increases in Cai2+ and Isc suggest that Cai2+ is the second messenger for stimulation of apical membrane conductance.

Petzel

Ganz²,

Nestler³

et al. 1992

J. Clin. Invest.

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“…When the rate of Na' absorption was increased by isoproterenol, the calcium ionophore A-23 187 decreased the Isc. An inhibition of Na' absorption by an increase in the intracellular Ca2" concentration has also been observed in renal epithelia and is thought to result from inhibition of apical Na' channels (15)(16)(17).…”

Section: Resultsmentioning

confidence: 95%

“…Subsequent addition of phenylephrine (10-6 M, submucosal solution) did not alter the Isc: Isc was 34.7±6.0 before and 34.3±8.0 after the addition of phenylephrine (n = 7). An increase in cell calcium concentration is thought to inhibit Na+ absorption in a variety of epithelia (15,16), primarily by inhibiting Na+ entry at the apical membrane (17). To determine if an increase in cell calcium might inhibit Na+ absorption in airway epithelium, we first stimulated Isc with 8-Br-cAMP and then added A-23 187.…”

Section: Resultsmentioning

confidence: 99%

Regulation of sodium absorption by canine tracheal epithelium.

Cullen¹,

Welsh²

1987

J. Clin. Invest.

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To regulate the quantity of respiratory tract fluid, the airway epithelium either secretes chloride, Cl-, or reabsorbs sodium, Na'. Many secretagogues inhibit Na' absorption, but the decrease may result from a fall in the electrochemical gradient for Na' absorption. We examined regulation of Na' absorption independent of CL-secretion, by bathing canine tracheal epithelium in Cl--free, gluconate Ringers solution. Prostaglandin E2, 2-chloroadenosine, and isoproterenol increased short-circuit current (Isc) and the rate of Na' absorption. In contrast, indomethacin, which inhibits endogenous prostaglandin production, decreased Isc. These agents regulate cellular levels ofcAMPY, direct addition of 8-Br-cAMP also acutely increased Isc. We examined chronic regulation of Na' absorption in cell monolayers grown on permeable supports in serum-free media. Exposure to aldosterone for two days increased baseline Isc by 50% and the amilorideinhibitable current by 55%. These data indicate that Na' absorption is both acutely and chronically regulated in the airway epithelium.

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“…However, it is also possible that these blockers have other effects. For example, quinidine has been shown to block Ca channels in other epithelia (WINDHAGER, 1983). The inhibition of the SCC by quinidine may be due to the blockage of the Ca channels.…”

Section: Discussionmentioning

confidence: 99%

Potassium channel blockers inhibit anion secretion in cultured rat epididymal epithelium.

Wong

1989

Jpn.J.Physiol

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The effect of putative K channel blockers on anion secretion has been studied in primary monolayer cultures of rat epididymal cells using the short circuit current technique. Under basal conditions, monolayers had a transepithelial potential difference of about 2-3 mV, apical side negative and a short circuit current (SCC) of about 2 pA • cm-2. The transepithelial resistance was about 500 Q • cm2. Addition of adrenaline (0.23 pM, basolaterally) caused the SCC to rise to a peak value of about 10.5pA • cm-2 and then stabilized at about 4pA • cm-2 after 15 min. This rise in the short circuit current has previously been shown to be due to an increase in net anion secretion from the basolateral to the apical medium. In tissues stimulated with adrenaline, addition of barium (Ba) to the apical side did not affect the adrenaline-induced SCC, but addition to the basolateral side caused a dose-dependent inhibition of the current with an IC50 value (concentration required to inhibit 5000 of the current) of 0.92 mM. At Ba concentration of 5 mM, the adrenaline-induced SCC was completely abolished. There was no effect on transepithelial resistance. Addition of tetraethylamonium (TEA) (16 mM) to the apical or basolateral side had no significant effect on the adrenaline-stimulated SCC. Lidocaine and quinidine inhibited the adrenaline-stimulated SCC when added either to the apical or basolateral bathing solution. The IC50 values for lidocaine were 0.42 mM and 0.35 mM for basolateral and apical application, respectively. The IC50 values for quinidine were 0.062 mM and 0.050 mM for basolateral and apical application, respectively. In all cases there was no change in tissue resistance. It is proposed that in the basolateral membrane of the epididymal cells, there is a component which is sensitive to putative K channel blockers. It is likely that it is a K channel. As in other secretory cells, this channel plays an important role in secretion.

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Regulatory Role of Intracellular Calcium Ions in Epithelial Na Transport

Cited by 78 publications

References 29 publications

Correlates of aldosterone-induced increases in Cai2+ and Isc suggest that Cai2+ is the second messenger for stimulation of apical membrane conductance.

Correlates of aldosterone-induced increases in Cai2+ and Isc suggest that Cai2+ is the second messenger for stimulation of apical membrane conductance.

Regulation of sodium absorption by canine tracheal epithelium.

Potassium channel blockers inhibit anion secretion in cultured rat epididymal epithelium.

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