Electrophysiological correlates of fluid transport in cultured porcine thyroid cells

1988 ◽  
Vol 119 (2) ◽  
pp. 309-314 ◽  
Author(s):  
J. Pearson ◽  
J. R. Bourke ◽  
S. W. Manley ◽  
G. J. Huxham ◽  
T. Matainaho ◽  
...  
Keyword(s):  
Sodium Transport ◽  
Fluid Transport ◽  
Chloride Transport ◽  
Chloride Ion ◽  
Prostaglandin E ◽  
Culture Dish ◽  
Thyroid Cells ◽  
Ion Substitution ◽  
Basal Pole ◽  
Sodium Extrusion

ABSTRACT Confluent monolayers of cultured porcine thyroid cells transport fluid from the apical to the basal surface, forming circumscribed zones of detachment from the culture dish substrate (domes). The transepithelial potential (TEP), positive on the basal side, was 12·9 ± 0·4 (s.e.m.) mV (n = 93) under control conditions, increasing to 38·9 ± 0·3 mV (n = 281) when fluid transport was stimulated by prostaglandin E2 (PGE2; 1 μmol/l). Forskolin (1 μmol/l) and 8-(4-chlorophenylthio) adenosine 3′,5′-cyclic monophosphate (0·5 mmol/l) were also effective in increasing TEP. Addition of amiloride in concentrations sufficient to block fluid transport (100 μmol/l) reduced the TEP to 5·8 ± 0·3 mV (n=76). Substitution of N-methyl-d-glucamine for sodium in the medium reduced the PGE2-stimulated TEP to 13·4 ± 0·8 mV (n = 32). Substitution of gluconate for chloride increased the TEP to 40·3 ± 0·4 mV (n = 160). Removal of bicarbonate or potassium from the medium, or addition of ouabain (200 μmol/l) were also effective in reducing the TEP. In media of low bicarbonate concentration (1 mmol NaHCO3/l), acetazolamide (1 mmol/l) reduced the TEP. Fluid transport by the monolayer as measured by the change in height of domes was increased by PGE2 (1 μmol/l). PGE2-stimulated fluid transport was inhibited by sodium or chloride ion substitution, bicarbonate removal or the addition of ouabain (200 μmol/l) or amiloride (100 μmol/l). It was concluded that fluid transport in thyroid monolayers is mediated by rheogenic sodium transport with chloride transport being passive, electrogenically coupled to sodium transport. Sodium entry to the apical pole of the cells occurs by an amiloride-sensitive mechanism, and sodium extrusion at the basal pole depends on the Na+/K+ ATPase. J. Endocr. (1988) 119, 309–314

Cyclic AMP-stimulated fluid transport in the thyroid: influence of thyroid stimulators, amiloride and acetazolamide on the dynamics of domes in monolayer cultures of porcine thyroid cells

1987 ◽  
Vol 115 (1) ◽  
pp. 19-NP ◽  
Author(s):  
J. R. Bourke ◽  
T. Matainaho ◽  
G. J. Huxham ◽  
S. W. Manley
Keyword(s):  
Cyclic Amp ◽  
Fluid Transport ◽  
Dome Height ◽  
Prostaglandin E ◽  
Culture Dish ◽  
Thyroid Cells ◽  
Monolayer Cultures ◽  
Dome Growth ◽  
Basal Pole ◽  
Methyl Xanthine

ABSTRACT Confluent monolayer cultures of porcine thyroid cells form dome-shaped elevations by local separation from the plastic culture dish. Formation of domes by epithelial cells in culture is generally considered to be evidence of fluid transport. A computer-controlled data acquisition system was developed to quantitate fluid transport in thyroid cultures by serial measurements of dome elevation. Thyrotrophin (10 mU/ml), prostaglandin E2 (PGE2; 0-01-1 μmol/l), forskolin (1 μmol/l), 8-(4-chlorophenylthio)adenosine 3′:5′-cyclic monophosphate (0.5 mmol/l) and 3-isobutyl-1-methyl-xanthine (0.5 mmol/l) promoted increases in dome height over 5–120 min. Dome growth in the presence of PGE2 (1 μmol/l) was inhibited by amiloride (0.1–100 μmol/l), ouabain (200 μmol/l), or by removal of bicarbonate and glucose from the medium. In media of reduced bicarbonate concentration (1 mmol/l compared with the control concentration of 10 mmol/l), dome growth was inhibited by acetazolamide (0.01– 1 mmol/l). These data are consistent with cyclic AMP-stimulated transport of fluid from apical to basal pole of the cells, dependent on sodium entry through the apical pole by an Na+/H+ exchanger. J. Endocr. (1987) 115, 19-26

Inhibitory effects of amiloride and its analogues on prostaglandin E2-stimulated fluid transport by cultured porcine thyroid cells: evidence for apical membrane Na+ channels

1989 ◽  
Vol 123 (1) ◽  
pp. 93-97 ◽  
Author(s):  
T. Matainaho ◽  
E. J. Cragoe ◽  
S. W. Manley ◽  
G. J. Huxham ◽  
J. V. Pearson ◽  
...  
Keyword(s):  
Fluid Transport ◽  
Apical Membrane ◽  
Dome Height ◽  
Prostaglandin E ◽  
Confidence Limits ◽  
Inhibitory Effects ◽  
Culture Dish ◽  
Basal Surface ◽  
Thyroid Cells ◽  
Transport Fluid

ABSTRACT Confluent monolayers of cultured porcine thyroid cells transport fluid from the apical to the basal surface, forming circumscribed zones of detachment (domes) from the culture dish substrate. Fluid transport, as measured by increase in dome height, was stimulated by prostaglandin E2 (PGE2; 1 μmol/l) and inhibited by amiloride (0·1–100 μmol/l). Values of the inhibition constant (Ki) with 95% confidence limits for each of a series of amiloride analogues were: 3′,4′-dichlorobenzamil (DCB), 0·090 (0·045–0·18) μmol/l; 2′,4′;-dimethylbenzamil (DMB), 0·14 (0·074–0·27) μmol/l; amiloride, 0·72 (0·33–1·8) μmol/l; 5-(N,N-hexamethylene)amiloride (HMA), 17 (5·9–43) μmol/l; 5-(N-ethyl-N-isopropyl)amiloride (EIPA), 33 (15–71) μmol/l; and 2-guanidinobenzimidazole, 243 (110–570) μmol/l. Triaminopyrimidine was ineffective at concentrations up to 1 mmol/l. Since DCB and DMB are known to have a higher affinity for Na+ channels, while HMA and EIPA show higher affinity for Na+/H+ antiports, it was concluded that PGE2-stimulated fluid transport involved an apical membrane Na+ channel. Journal of Endocrinology (1989) 123, 93–97

Epidermal growth factor (EGF) inhibits the secretomotor response of the thyroid: effects of EGF on radioiodine turnover and fluid transport in cultured porcine thyroid cells

1991 ◽  
Vol 128 (2) ◽  
pp. 213-218 ◽  
Author(s):  
J. R. Bourke ◽  
S. Murdoch ◽  
S. W. Manley ◽  
T. Matainaho ◽  
G. J. Huxham ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cyclic Amp ◽  
Fluid Transport ◽  
Prostaglandin E ◽  
Thyroid Cell ◽  
Ionophore A23187 ◽  
Maximal Effect ◽  
Thyroid Cells ◽  
Epidermal Growth

ABSTRACT Thyrotrophin (4-256 μU/ml) promoted an increase in the rate of release of radioiodine from the organic iodine pool of cultured porcine thyroid cells in follicular formations. This action of TSH was antagonized by low concentrations of epidermal growth factor (EGF; 0·1–5 nmol/l). The maximal effect of EGF was reached by 0·5 nmol/l. EGF (0·5–5 nmol/l) also inhibited the stimulatory effect of 8-chloro cyclic AMP (0·06–1·0 nmol/l) on radioiodine turnover. Exposure of thyroid cultures to media with a calcium concentration of 17·7 μmol/l (1% of normal) resulted in a very marked increase in the rate of release of radioiodine. The effect of TSH in low-calcium media was to inhibit the increased release of radioiodine, and EGF (0·5 nmol/l) antagonized this inhibitory effect of TSH. The calcium ionophore, A23187, stimulated radioiodine release in a dose-dependent fashion, and EGF (1·7 nmol/l) inhibited this response. Fluid transport in thyroid monolayers was stimulated by prostaglandin E2 (PGE2; 1 μmol/l). EGF (5 nmol/l) also stimulated fluid transport, but antagonized the effect of PGE2 added subsequently. It was concluded that EGF exerted acute antagonistic effects on thyroid cell responses in vitro to cyclic AMP and agents promoting accumulation of cyclic AMP in time-frames too short for these inhibitory effects to be attributable to the dedifferentiative effect of the growth factor. Journal of Endocrinology (1991) 128, 213–218

Ionic requirements of proximal tubular sodium transport. III. Selective luminal anion substitution

1979 ◽  
Vol 236 (3) ◽  
pp. F268-F277 ◽  
Author(s):  
R. Green ◽  
J. H. Bishop ◽  
G. Giebisch
Keyword(s):  
Sodium Transport ◽  
Concentration Gradient ◽  
Fluid Transport ◽  
Chloride Transport ◽  
Chloride Concentration ◽  
Transport Systems ◽  
Sodium Reabsorption ◽  
Perfusion Fluid ◽  
Moderate Amount ◽  
Proximal Tubular

The effect of substitution of luminal anions on sodium and fluid absorption in rat renal proximal convoluted tubules was studied with continuous luminal microperfusion methods. Substitution of bicarbonate in the control Ringer perfusion fluid by 25 mM acetate reduced net sodium reabsorption by 40%; substitution by chloride reduced it by 25%; and substitution by cyclamate reduced it by 70%. Infusion of acetazolamide reduced net sodium and fluid transport in all cases except chloride-Ringer perfusion. Cyanide added to the perfusion fluid inhibited fluid and sodium movement completely when there was no imposed chloride concentration gradient, but only reduced fluid and solute movement by 68% when a nominal 36 mM transepithelial chloride concentration gradient existed. We conclude from these observations that passive forces for sodium reabsorption can account for a moderate amount of sodium transport, that the effects of acetazolamide in low concentrations are dependent on the presence of bicarbonate in the lumen, and that some anions alter net sodium transport either by reducing the availability of permeant anion for co-transport with sodium or by a direct effect on the sodium and/or chloride transport systems.

N-{(2RS)-2-Hydroxy-3-[2-(3-phenylpropanoyl)phenoxy]propyl}propanaminium chloride

2006 ◽  
Vol 62 (5) ◽  
pp. o1694-o1695
Author(s):  
Massimo Bambagiotti-Alberti ◽  
Bruno Bruni ◽  
Ferdinando Costantino ◽  
Massimo Di Vaira ◽  
Valerio Giannellini
Keyword(s):  
Hydrogen Bonds ◽  
Hydroxy Group ◽  
Antiarrhythmic Drug ◽  
Sodium Transport ◽  
Title Compound ◽  
Crystal Packing ◽  
Chloride Ion

The title compound, propafenone hydrochloride, C21H28NO3 +·Cl−, is a potent antiarrhythmic drug, which acts by blocking channels for sodium transport across cell borders. The crystal packing is essentially controlled by a system of hydrogen bonds involving the quaternary N atom, the (disordered) hydroxy group and the chloride ion.

Evidence for electroneutral sodium chloride transport in rat proximal convoluted tubule

1986 ◽  
Vol 250 (4) ◽  
pp. F644-F648
Author(s):  
K. J. Howlin ◽  
R. J. Alpern ◽  
C. A. Berry ◽  
F. C. Rector
Keyword(s):  
Sodium Chloride ◽  
Active Transport ◽  
Sodium Transport ◽  
Chloride Transport ◽  
Proximal Convoluted Tubule ◽  
Organic Solutes ◽  
Nacl Transport ◽  
Proximal Tubular ◽  
High Chloride

One- to two-thirds of NaCl absorption in the late proximal convoluted tubule (no luminal organic solutes present) is inhibited by cyanide and thus is dependent on active transport. To examine whether this active transport-dependent NaCl transport is electrogenic or electroneutral, the effect of cyanide on transepithelial potential difference (PD) was measured in the rat proximal convoluted tubule microperfused in vivo. In the presence of an ultrafiltrate-like luminal perfusate containing glucose and alanine, cyanide addition caused the transepithelial PD to change from -0.44 +/- 0.04 to -0.05 +/- 0.03 mV (P less than 0.001). In the presence of a late proximal tubular fluid (high chloride, low bicarbonate, no organics), the transepithelial PD was 1.23 +/- 0.06 mV and was unchanged at 1.19 +/- 0.05 mV after cyanide addition (NS). To eliminate the possibility that an effect of cyanide on a putative acidification-dependent lumen-positive PD was concealing an effect on an electrogenic sodium transport-dependent lumen-negative PD, the above studies were repeated in the presence of acetazolamide. Cyanide did not affect the transepithelial PD (1.17 +/- 0.05 vs. 1.07 +/- 0.06 mV, NS). We conclude that, although cyanide-inhibitable NaCl transport is electrogenic in the presence of luminal organic solutes, it does not generate a transepithelial PD in their absence and therefore is electroneutral.

Chloride ion substitution in alkali bromide surfaces: cooperative interactions, including a surface transition

1972 ◽  
Vol 327 (1568) ◽  
pp. 97-122 ◽  
Keyword(s):  
Chloride Ion ◽  
Surface Compound ◽  
Compound K ◽  
Two Phase ◽  
Mobile State ◽  
Cooperative Interactions ◽  
Surface Transition ◽  
Halogen Exchange ◽  
Ion Substitution ◽  
Anions And Cations

Thermodynamic information on surfaces of vacuum -sublimed NaBr and KBr has been obtained by stud y in g equilibrium in: ( a ) halogen exchange between HCl(g) and the surfaces; ( b ) adsorption of HCl an d HBr. Both types of study disclose a transition in the pure KBr surface at 293 K, induced by HCl adsorption. From exchange results, Δ H t = + 18.4 kJ mol -1 and Δ S t = + 62.8 J mol -1 K -1 . Adsorption indicates a similar transition in the pure NaBr surface at 268 K. It is proposed that, in the transition, anions acquire free two-dimensional translation. Comparison with exchange studies of Harrison & Siddiqui (1962) on solution-precipitated NaBr suggests that in those surfaces both anions and cations were mobile. Partly exchanged surfaces show non-ideal behaviour which is interpreted in term s of repulsion between like anions up to a threshold distance beyond which they attract each other. In KBr, the effects are large, and lead to formation of a surface compound K 4 Br 3 Cl. Beyond this composition further Cl - does not substitute into the KBr surface below 10 °C at ordinary HCl pressures. The transition temperature of KBr surfaces 5 to 15 % exchanged with Cl - is depressed. This is attributed to a tendency to two-phase separation of the surface as KBr and K 4 Br 3 Cl. In NaBr, corresponding interactions are weaker, and give only slight non-ideality. This has been matched by computations using the 'quasi-chemical’ aproximation, with first-neighbour repulsion of like anions about 2 kJ mol -1 and similar second-neighbour attraction. The effects are believed to be associated with the Verwey distortion. They are smaller in NaBr than in KBr because the former is being studied with anions in the mobile state in which such effects are only residual. Data for KBr suggest that, above its transition, it may lose these enthalpy effects more completely than NaBr and acquire an entropy-dominated non-ideality like that found by Harrison & Siddiqui (1962) in solution-precipitated NaBr.

Mitochondrial permeability to chloride ion

1975 ◽  
Vol 228 (1) ◽  
pp. 122-126 ◽  
Author(s):  
MW Weiner
Keyword(s):  
Rat Liver ◽  
Chloride Transport ◽  
Biological Membranes ◽  
Chloride Ion ◽  
The Other ◽  
Beef Heart ◽  
Inner Membrane ◽  
Mitochondrial Permeability ◽  
Mitochondrial Inner Membrane ◽  
Chloride Salts

It is generally accepted that the inner membrane of the mitchondrion is not penetrated by chloride ion, in contrast to other biological membranes which are chloride permeable. In this report mitochondrial permeablity to chloride ion has been reevaluated by the measurement of passive swelling in isotonic chloride-containing solutions in the presence of an uncoupling agent. Under these conditions, mitochondria prepared from rat liver or beef heart show a definite uptake of wide variety of chloride salts. Mitochondrial chloride transport appears to be electrogenic, as is the transmembrane movement of the other halides. Therefore, the mitochondrial inner membrane shares with other biological membranes a definite permeability to this ubiquitous anion.

scholarly journals Prolactin stimulates sodium and chloride ion channels in A6 renal epithelial cells

2015 ◽  
Vol 308 (7) ◽  
pp. F697-F705 ◽  
Author(s):  
Megan M. Greenlee ◽  
Jeremiah D. Mitzelfelt ◽  
Billie Jeanne Duke ◽  
Otor Al-Khalili ◽  
Hui-Fang Bao ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Chloride Transport ◽  
Anion Channel ◽  
Chloride Ion ◽  
Peptide Hormone ◽  
Open Probability ◽  
Renal Epithelial Cells ◽  
Electrophysiological Properties ◽  
A6 Cells ◽  
Pka Pathway

Many hormonal pathways contribute to the regulation of renal epithelial sodium channel (ENaC) function, a key process for maintaining blood volume and controlling blood pressure. In the present study, we examined whether the peptide hormone prolactin (PRL) regulates ENaC function in renal epithelial cells (A6). Basolateral application of several different concentrations of PRL dramatically stimulated the transepithelial current in A6 cells, increasing both amiloride-sensitive (ENaC) and amiloride-insensitive currents. Using cell-attached patch clamp, we determined that PRL increased both the number ( N) and open probability ( Po) of ENaC present in the apical membrane. Inhibition of PKA with H-89 abolished the effect of PRL on amiloride-sensitive and insensitive transepithelial currents and eliminated the increase in ENaC NPo with PRL exposure. PRL also increased cAMP in A6 cells, consistent with signaling through the cAMP-dependent PKA pathway. We also identified that PRL induced activity of a 2-pS anion channel with outward rectification, electrophysiological properties consistent with ClC4 or ClC5. RT-PCR only detected ClC4, but not ClC5 transcripts. Here, we show for the first time that PRL activates sodium and chloride transport in renal epithelial cells via ENaC and ClC4.

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