Dual effect of N-ethylmaleimide on Cl? transport across the thin ascending limb of Henle's loop

Masashi Imai; Yoshiaki Kondo; Chizuko Koseki; Koji Yoshitomi

doi:10.1007/bf00582373

Effect of pH on Cl- transport in TAL of Henle's loop

AJP Renal Physiology ◽

10.1152/ajprenal.1987.253.6.f1216 ◽

1987 ◽

Vol 253 (6) ◽

pp. F1216-F1222 ◽

Cited By ~ 1

Author(s):

Y. Kondo ◽

K. Yoshitomi ◽

M. Imai

Keyword(s):

Choline Chloride ◽

Chloride Diffusion ◽

Ph Titration ◽

Cl Transport ◽

Henle's Loop ◽

Basolateral Side ◽

Diffusion Voltage ◽

Bathing Fluid ◽

Cl Permeability

To further characterize the mechanism of Cl- transport across the hamster thin ascending limb (TAL) of Henle's loop, we examined effects of pH on Cl- permeability as determined by either the choline chloride diffusion voltage or the lumen-to-bath 36Cl flux in the isolated segments perfused in vitro. When pH of the bathing fluid or the perfusate was reduced from 7.4 to 5.8, the Cl(-)-Na+ permeability ratio (PCl/PNa) was reduced from 2.77 +/- 0.21 to 0.48 +/- 0.02 (n = 7, P less than 0.01) or from 2.55 +/- 0.15 to 0.81 +/- 0.11 (n = 6, P less than 0.01), respectively. At 37 degrees C, when the pH of the bathing fluid was reduced from 7.4 to 6.2, the lumen-to-bath flux coefficient for 36Cl (X10(-7) cm2/s) was reduced from 84.8 +/- 7.5 to 20.4 +/- 3.2 (n = 7, P less than 0.01), whereas the value for 22Na was unchanged (27.3 +/- 2.9 vs. 25.3 +/- 2.5, n = 5). From the pH titration curves for PCl/PNa, pKa values for proton binding were 6.31 and 5.78, and Hill's coefficients were 2.1 and 2.3 on the basolateral side and on the luminal side, respectively. Alkalinization had little or no effect on the Cl- permeability. At room temperature, the acid pH did not affect the Cl- permeability. Intracellular acidification with o-nitrophenylacetate also decreased the Cl- permeability.(ABSTRACT TRUNCATED AT 250 WORDS)

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Effects of arginine vasopressin on the thin ascending limb of Henle's loop of hamsters

AJP Renal Physiology ◽

10.1152/ajprenal.1982.243.2.f167 ◽

1982 ◽

Vol 243 (2) ◽

pp. F167-F172 ◽

Cited By ~ 8

Author(s):

M. Imai ◽

E. Kusano

Keyword(s):

Adenylate Cyclase ◽

Arginine Vasopressin ◽

Chloride Transport ◽

Cyclase Activity ◽

Adenylate Cyclase Activity ◽

Renal Tubules ◽

Thick Ascending Limb ◽

Cl Transport ◽

Henle's Loop ◽

Perfusion Studies

Arginine vasopressin (AVP) has been shown to stimulate active Cl transport across the medullary thick ascending limb of Henle's loop (MAL) in association with an increase in adenylate cyclase activity. To determine whether the failure to demonstrate active Cl transport across the thin ascending limb of Henle's loop (TAL) in previous in vitro perfusion studies was due to the absence of AVP in the preparation, we examined the effect of AVP on adenylate cyclase activity and Cl transport in the hamsters TAL. AVP (1 mU/ml) increased adenylate cyclase activity in the hamster TAL (20.7 +/- 5.2 control vs. 46.2 +/- 10.1 fmol . mm-1 . 30 min-1, n = 6, P less than 0.05) but not in the descending limb (27.8 +/- 7.0 control vs. 20.4 +/- 2.7, n = 4, P less than 0.05). When both MAL and TAL were perfused, a lumen-positive transepithelial voltage (Vt) was observed. The Vt was increased by adding 1 or 10 mU/ml AVP to the bath. When only the TAL was perfused, the Vt was not different from zero. Similar results were obtained in mouse renal tubules. In other experiments, AVP did not affect the diffusion potential generated when a transepithelial NaCl gradient was present. AVP or dibutyryl cAMP caused little or no change in efflux of radioactive chloride across the hamster TAL. These findings suggest that electrogenic chloride transport is not demonstrable in the TAL even in the presence of AVP. The physiologic role of AVP-sensitive adenylate cyclase in the TAL remains to be established.

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Vasopressin stimulates Cl- transport in ascending thin limb of Henle's loop in hamster.

Journal of Clinical Investigation ◽

10.1172/jci117836 ◽

1995 ◽

Vol 95 (4) ◽

pp. 1623-1627 ◽

Cited By ~ 19

Author(s):

N Takahashi ◽

Y Kondo ◽

O Ito ◽

Y Igarashi ◽

K Omata ◽

...

Keyword(s):

Cl Transport ◽

Henle's Loop ◽

Thin Limb

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Effects of anion transport inhibitors and ion substitution on Cl- transport in TAL of Henle's loop

AJP Renal Physiology ◽

10.1152/ajprenal.1987.253.6.f1206 ◽

1987 ◽

Vol 253 (6) ◽

pp. F1206-F1215 ◽

Cited By ~ 4

Author(s):

Y. Kondo ◽

K. Yoshitomi ◽

M. Imai

Keyword(s):

Inhibitory Effect ◽

Anion Transport ◽

Diffusion Potential ◽

Disulfonic Acid ◽

Cl Transport ◽

Ionic Substitution ◽

Henle's Loop ◽

Transport Inhibitors ◽

Diffusion Voltage

To identify the mechanism of Cl- transport across the thin ascending limb of Henle's loop (TAL), we examined effects of anion transport inhibitors and ionic substitution in the isolated segments of hamsters using the in vitro microperfusion technique. 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) at 10(-3) M changed the NaCl diffusion voltage (Vt) to the orientation that corresponds to the decrease in the Cl(-)-Na+ permeability ratio when it was added either to the bath or to the lumen. DIDS, added to the bath or to the lumen decreased the lumen-to-bath flux coefficient for 36Cl, KCl-(1----b) (X10(-7) cm2/s), from 74.5 +/- 2.1 to 17.9 +/- 3.6 and from 77.7 +/- 3.6 to 51.1 +/- 5.4, respectively, whereas it had little effect on the flux coefficient for 22Na, KNa+(1----b). Elimination of HCO3- slightly increased rather than decreased both NaCl diffusion potential and KCl-(1----b), indicating that Cl- transport is independent of HCO3- transport. Phloretin at 10(-3) M inhibited both diffusion potential and KCl-(1----b) to a similar extent as DIDS did. KNa+(1----b) was also changed little. The inhibitory effect of phloretin was rapid and reversible. Phloridzin was ineffective. Furosemide added to the bath at 10(-3) M decreased Vt and KCl-(1----b) from 29 +/- 0.9 to 5.3 +/- 0.7 mV and from 75.7 +/- 3.9 to 62.8 +/- 4.1 X 10(-7) cm2/s, respectively; but it was ineffective when added to the lumen. Elimination of Na+ caused only a small decrease in KCl-(1----b) from 119.2 +/- 6.9 to 107.3 +/- 8.5 X 10(-7) cm2/s. Elimination of K+ and addition of Ba2+ did not change KCl-(1----b). From these observations, we conclude that Cl- transport across the TAL is distinct from Na+ and is not coupled with Na+, K+, or HCO3-.

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Dual actions of N ethylmaleimide (NEM) on Cl- transport across the thin ascending limb of Henle’s loop (TAL)

The Japanese Journal of Pharmacology ◽

10.1016/s0021-5198(19)58190-2 ◽

1987 ◽

Vol 43 ◽

pp. 128

Author(s):

Masashi Imai ◽

Yoshiaki Kondo ◽

Chizuko Koseki ◽

Koji Yoshitomi

Keyword(s):

Cl Transport ◽

Henle's Loop

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Effect of Ca2+ on Cl- transport in thin ascending limb of Henle's loop

AJP Renal Physiology ◽

10.1152/ajprenal.1988.254.2.f232 ◽

1988 ◽

Vol 254 (2) ◽

pp. F232-F239 ◽

Cited By ~ 3

Author(s):

Y. Kondo ◽

K. Yoshitomi ◽

M. Imai

Keyword(s):

Small Reduction ◽

Na Transport ◽

Ph Titration ◽

Cl Transport ◽

Titration Curves ◽

Henle's Loop ◽

Diffusion Voltage ◽

Bathing Fluid ◽

Cl Permeability

Effects of ambient Ca2+ concentration on Cl- transport across the thin ascending limb of Henle's loop (TAL) were examined by the in vitro microperfusion technique. When Ca2+ concentration in the bathing fluid was decreased from 1.5 mM to nominally 0 mM at 37 degrees C, the relative permeability of Cl- to Na+ (PCl/PNa) estimated from the NaCl diffusion voltage changed from 2.44 +/- 0.20 to 1.27 +/- 0.16 (n = 7, P less than 0.01). When Ca2+ concentration of the luminal fluid was reduced, PCl/PNa was unchanged. When Ca2+ concentration in the bathing fluid was changed from 4.5 to nominally 0 mM, the lumen-to-bath flux coefficient for 36Cl (K36Cl(l----b)) was decreased, whereas the value for 22Na was unchanged, indicating that the reduction of Ca2+ concentration in the bathing fluid selectively inhibits Cl- transport without affecting Na+ transport. By contrast, at 23 degrees C, the elimination of Ca2+ from the bathing fluid caused only a small reduction of PCl/PNa. Although at 23 degrees C acidification of the bathing fluid caused only little or no decrease in Cl- permeability, the elimination of Ca2+ from the bathing fluid under acid pH markedly suppressed the (K36Cl(l----b)) (10(-7) cm2/s). The pH titration curves of relative Cl- permeability examined at three different Ca2+ concentrations at 37 degrees C revealed that the interaction between proton and Ca2+ was noncompetitive. Addition of quin 2-AM, which reduced intracellular Ca2+ concentration, to the bath caused an irreversible suppression of Cl- permeability, suggesting that the decrease in intracellular Ca2+ concentration also inhibits the Cl- transport across the TAL.(ABSTRACT TRUNCATED AT 250 WORDS)

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The Use of the Human Erythrocyte as a Model for Studying the Action of Diuretics on Sodium and Chloride Transport

Clinical Science ◽

10.1042/cs0540679 ◽

1978 ◽

Vol 54 (6) ◽

pp. 679-683 ◽

Cited By ~ 2

Author(s):

B. A. Brooks ◽

A. F. Lant

Keyword(s):

Transport System ◽

Human Erythrocyte ◽

Chloride Transport ◽

Transport Systems ◽

Na Transport ◽

Cl Transport ◽

Henle's Loop ◽

Low Concentrations ◽

Biochemical Action ◽

Chemical Analogue

1. The Na+ and Cl− transport systems of human erythrocytes have been compared for their sensitivities to diuretics known to act in the ascending limb of Henle's loop. In addition, chemical analogues of ‘loop’ compounds and also diuretics which act in other areas of the nephron have been examined. 2. The Na+ transport system lacks specificity with respect to inhibition by ‘loop’ diuretics and also a related chemical analogue studied at equivalent concentrations. 3. The Cl− transport system is inhibited, at low concentrations, by diuretics known to act in the ascending limb of Henle's loop. 4. Erythrocyte Cl− transport offers a useful model with which to study the biochemical action of diuretics.

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