scholarly journals Channels for water efflux and influx involved in volume regulation of murine spermatozoa

Reproduction ◽  
2008 ◽  
Vol 136 (4) ◽  
pp. 401-410 ◽  
Author(s):  
C Callies ◽  
T G Cooper ◽  
C H Yeung
Keyword(s):  
Water Transport ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Water Influx ◽  
Sodium Dependent ◽  
Water Efflux ◽  
Transport Inhibitors ◽  
Osmolyte Efflux ◽  
Solute Transporters ◽  
Volume Decrease

The nature of the membrane channels mediating water transport in murine spermatozoa adjusting to anisotonic conditions was investigated. The volume of spermatozoa subjected to physiologically relevant hypotonic conditions either simultaneously, or after isotonic pre-incubation, with putative water transport inhibitors was monitored. Experiments in which quinine prevented osmolyte efflux, and thus regulatory volume decrease (RVD), revealed whether water influx or efflux was being inhibited. There was no evidence that sodium-dependent solute transporters or facilitative glucose transporters were involved in water transport during RVD of murine spermatozoa since phloretin, cytochalasin B and phloridzin had no effect on volume regulation. However, there was evidence that Hg2+- and Ag+-sensitive channels were involved in water transport and the possibility that they include aquaporin 8 is discussed. Toxic effects of these heavy metals were ruled out by evidence that mitochondrial poisons had no such effect on volume regulation.

Regulation of cellular volume in rabbit ventricular myocytes: bumetanide, chlorothiazide, and ouabain

1991 ◽  
Vol 260 (1) ◽  
pp. C122-C131 ◽  
Author(s):  
K. Drewnowska ◽  
C. M. Baumgarten
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Ventricular Myocytes ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Volume Response ◽  
Rabbit Ventricular Myocytes ◽  
Cell Volumes ◽  
Measured Volume ◽  
Volume Decrease

Video microscopy was used to study the regulation of cell volume in isolated rabbit ventricular myocytes. Myocytes rapidly (less than or equal to 2 min) swelled and shrank in hyposmotic and hyperosmotic solutions, respectively, and this initial volume response was maintained without a regulatory volume decrease or increase for 20 min. Relative cell volumes (normalized to isosmotic solution, 1T) were as follows: 1.41 +/- 0.01 in 0.6T, 1.20 +/- 0.04 in 0.8T, 0.71 +/- 0.04 in 1.8T, and 0.57 +/- 0.03 in 2.6T. These volume changes were significantly less than expected if all of the measured volume was osmotically active water. Changes in width and thickness were significantly greater than changes in cell length. The idea that cotransport contributes to cell volume regulation was tested by inhibiting Na(+)-K(+)-2Cl- cotransport with bumetanide (BUM) and Na(+)-Cl- cotransport with chlorothiazide (CTZ). Under isotonic conditions, a 10-min exposure to BUM (1 microM), CTZ (100 microM), or BUM (10 microM) plus CTZ (100 microM) decreased relative cell volume to 0.87 +/- 0.01, 0.86 +/- 0.02, and 0.82 +/- 0.04, respectively. BUM plus CTZ also modified the response to osmotic stress. Swelling in 2.6T medium was 76% greater and shrinkage in 0.6T medium was 29% less than in the absence of diuretics. In contrast to the rapid effects of diuretics, inhibition of the Na(+)-K+ pump with 10 microM ouabain for 20 min did not affect cell volume in 1T solution. Nevertheless, ouabain decreased swelling in 0.6T medium by 52% and increased shrinkage in 1.8T medium by 34%. These data suggest that under isotonic conditions Na(+)-K(+)-2Cl- and Na(+)-Cl- cotransport are critical in establishing cell volume, but osmoregulation can compensate for Na(+)-K+ pump inhibition for at least 20 min. Under anisotonic conditions, the Na(+)-K+ pump and Na(+)-K(+)-2Cl- and/or Na(+)-Cl- cotransport are important in myocyte volume regulation.

Role of concentration and size of intracellular macromolecules in cell volume regulation

1997 ◽  
Vol 273 (2) ◽  
pp. C360-C370 ◽  
Author(s):  
J. C. Summers ◽  
L. Trais ◽  
R. Lajvardi ◽  
D. Hergan ◽  
R. Buechler ◽  
...  
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Molecular Physiology ◽  
Average Molecular Mass ◽  
Membrane Stretch ◽  
Ca2 Channels ◽  
Volume Decrease

To gain insight into the mechanism(s) by which cells sense volume changes, specific predictions of the macromolecular crowding theory (A. P. Minton. In: Cellular and Molecular Physiology of Cell Volume Regulation, edited by K. Strange. Boca Raton, FL: CRC, 1994, p. 181-190. A. P. Minton, C. C. Colclasure, and J. C. Parker. Proc. Natl. Acad. Sci. USA 89: 10504-10506, 1992) were tested on the volume of internally perfused barnacle muscle cells. This preparation was chosen because it allows assessment of the effect on cell volume of changes in the intracellular macromolecular concentration and size while maintaining constant the ionic strength, membrane stretch, and osmolality. The predictions tested were that isotonic replacement of large macromolecules by smaller ones should induce volume decreases proportional to the initial macromolecular concentration and size as well as to the magnitude of the concentration reduction. The experimental results were consistent with these predictions: isotonic replacement of proteins or polymers with sucrose induced volume reductions, but this effect was only observed when the replacement was > or = 25% and the particular macromolecule had an average molecular mass of < or = 20 kDa and a concentration of at least 18 mg/ml. Volume reduction was effected by a mechanism identical with that of hypotonicity-induced regulatory volume decrease, namely, activation of verapamil-sensitive Ca2+ channels.

Association of intrinsic pICln with volume-activated Cl− current and volume regulation in a native epithelial cell

1999 ◽  
Vol 276 (1) ◽  
pp. C182-C192 ◽  
Author(s):  
Lixin Chen ◽  
Liwei Wang ◽  
Tim J. C. Jacob
Keyword(s):  
Antisense Oligonucleotides ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Hypotonic Solution ◽  
Dependent Manner ◽  
Nonpigmented Ciliary Epithelial ◽  
The Relationship ◽  
Dose Dependent ◽  
Hypotonic Swelling ◽  
Volume Decrease

We investigated the relationship between pICln, the volume-activated Cl−current, and volume regulation in native bovine nonpigmented ciliary epithelial (NPCE) cells. Immunofluorescence studies demonstrated the presence of pICln protein in the NPCE cells. Exposure to hypotonic solution activated a Cl− current and induced regulatory volume decrease (RVD) in freshly isolated bovine NPCE cells. Three antisense oligonucleotides complementary to human pICln mRNA were used in the experiments. The antisense oligonucleotides were taken up by the cells in a dose-dependent manner. The antisense oligonucleotides, designed to be complementary to the initiation codon region of the human pICln mRNA, “knocked down” the pICln protein immunofluorescence, delayed the activation of volume-activated Cl− current, diminished the value of the current, and reduced the ability of the cells to volume regulate. We conclude that pIClnis involved in the activation pathway of the volume-activated Cl− current and RVD following hypotonic swelling.

Volume regulation initiated by Na(+)-nutrient cotransport in isolated mammalian villus enterocytes

1991 ◽  
Vol 260 (1) ◽  
pp. G26-G33 ◽  
Author(s):  
R. J. MacLeod ◽  
J. R. Hamilton
Keyword(s):  
Guinea Pig ◽  
Volume Regulation ◽  
Brush Border Membrane ◽  
Regulatory Volume Decrease ◽  
Membrane Vesicles ◽  
Relative Volume ◽  
Cell Shrinkage ◽  
K Channels ◽  
Volume Decrease ◽  
Pig Jejunum

We assessed ion transport during regulatory volume decrease (RVD) in jejunal villus enterocytes, isolated in suspension from guinea pig jejunum and swollen by exposure to L-alanine (L-Ala) or D-glucose (D-Glc) in the presence of Na+. Cell volume was measured electronically. Relative volume of cells (rel vol: cell vol/isotonic vol) within 1 min of L-Ala (20 mM) addition increased (1.10 +/- 0.03, P less than 0.005), but by 5 min there was no difference between cells in L-Ala or 20 mM D-Ala (0.95 +/- 0.02). Cell shrinkage after maximal swelling was greater with L-Ala than with D-Ala (14 +/- 4 vs. 2 +/- 1%, P less than 0.01). Initial swelling generated by L-Ala required extracellular Na+ (P less than 0.02). Volume increased 30 s after D-Glc (20 mM), and cells were larger than cells treated with L-Glc (1.04 +/- 0.01 vs. 0.95 +/- 0.01, P less than 0.001); subsequent cell shrinkage was complete in 2 min (8 +/- 2%, P less than 0.05). Swelling generated by methyl alpha-D-glucoside was prevented by 0.1 mM phloridzin (P less than 0.05). RVD after D-Glc swelling was prevented by inhibitors of K+ channels, 5 mM Ba2+ (P less than 0.001), 100 microM quinine (P less than 0.005), or 25 mM TEA (P less than 0.02), but the same inhibitors completely prevented L-Ala swelling. All inhibitors had no effect on L-Ala uptake into brush-border membrane vesicles in presence of Na+ gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

Cation transport in mouse erythrocytes: role of K(+)-Cl- cotransport in regulatory volume decrease

1995 ◽  
Vol 268 (4) ◽  
pp. C894-C902 ◽  
Author(s):  
C. C. Armsby ◽  
C. Brugnara ◽  
S. L. Alper
Keyword(s):  
Volume Regulation ◽  
Inhibitory Concentration ◽  
Inbred Mouse ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Cation Transport ◽  
Hypotonic Medium ◽  
Hypotonic Swelling ◽  
Volume Decrease

We investigated cation transport and cell volume regulation in erythrocytes of CD1 and C57/B6 mice. Swelling of cells from either strain stimulated K+ efflux that was insensitive to ouabain, bumetanide, and clotrimazole. Seventy-five percent of swelling-induced K+ efflux was Cl- dependent (inhibited by sulfamate or methanesulfonate, partially by NO3-, but not by SCN-) and was inhibited by okadaic acid (OA; 50% inhibitory concentration = 18 +/- 6 nM in CD1 and 10 +/- 4 nM in C57/B6). In both strains, K+ efflux into isotonic medium was stimulated by staurosporine or by N-ethylmaleimide, and the latter was partially blocked by pretreatment of cells with OA. When cells of either strain were incubated in hypotonic medium or preswollen isosmotically with nystatin, OA-sensitive regulatory volume decrease (RVD) and K+ loss were observed. RVD produced by hypotonic swelling was prevented by Cl- replacement with sulfamate or methanesulfonate. These properties suggest the presence in outbred and inbred mouse erythrocytes of RVD mediated by K(+)-Cl- cotransport.

Basolateral K+, Cl-, and HCO3- conductances and cell volume regulation in rabbit PCT

1993 ◽  
Vol 264 (2) ◽  
pp. F365-F376 ◽  
Author(s):  
P. Macri ◽  
S. Breton ◽  
J. S. Beck ◽  
J. Cardinal ◽  
R. Laprade
Keyword(s):  
Volume Regulation ◽  
Basolateral Membrane ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Temporal Variations ◽  
Hypotonic Shock ◽  
Control Value ◽  
Water Efflux ◽  
To Come ◽  
Cellular Water

The relationship between changes in cellular volume, intracellular pH (pHi), basolateral membrane potential (VBL), and membrane partial basolateral conductances to K+ (tK) and Cl- (tCl) and mediated by the Na-HCO3 cotransporter (tNaHCO3) was determined in the collapsed proximal convoluted tubule (PCT) submitted to a 125-mosmol/kg hypotonic shock. The shock that produces a rapid swelling followed by partial volume regulation was accompanied by a rapid and transient VBL hyperpolarization of 10.0 +/- 1.5 mV and a second gradual hyperpolarization of 5.0 +/- 0.7 mV with respect to a control value of -44.0 +/- 4.6 mV.tK was 0.12 +/- 0.03 in control, increased transiently to 0.15 +/- 0.03, and then gradually increased to reach 0.32 +/- 0.06 at the end of hypotonic shock. In contrast, tCl was 0.03 +/- 0.01 in control, increased rapidly to a maximum of 0.16 +/- 0.01, and then decreased slowly to 0.08 +/- 0.02. During the same period, tNaHCO3 decreased rapidly from 0.41 +/- 0.04 to a minimum of 0.11 +/- 0.02 and slowly reincreased to reach 0.16 +/- 0.01.pHi increased transiently from 7.09 +/- 0.03 in control to 7.24 +/- 0.05 to come back gradually to 7.15 +/- 0.05 at the end of the hypotonic period. The membrane absolute conductance mediated by the Na-HCO3 cotransporter was found to increase only slightly in hypotonic conditions, whereas that to K+ and Cl-, GK and GCl, increased by at least factors of 8 and 17, respectively, with the increase of GCl being much faster than that of GK. In addition, the temporal variations in GCl followed closely those of the cellular water efflux. We conclude that the hypotonic swelling leads to important increases in the conductive pathways for K+ and Cl- and that the Cl- conductance pathway appears to be the rate limiting step in triggering and supporting regulatory volume decrease.

scholarly journals Relative contribution of chloride channels and transporters to regulatory volume decrease in human glioma cells

2005 ◽  
Vol 288 (6) ◽  
pp. C1451-C1460 ◽  
Author(s):  
Nola Jean Ernest ◽  
Amy K. Weaver ◽  
Lauren B. Van Duyn ◽  
Harald W. Sontheimer
Keyword(s):  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Glioma Cells ◽  
Transport Processes ◽  
Sensitive Volume ◽  
Human Glioma ◽  
Human Glioma Cells ◽  
Experimental Conditions ◽  
Relative Contribution ◽  
Volume Decrease

Primary brain tumors (gliomas) often present with peritumoral edema. Their ability to thrive in this osmotically altered environment prompted us to examine volume regulation in human glioma cells, specifically the relative contribution of Cl− channels and transporters to this process. After a hyposmotic challenge, cultured astrocytes, D54-MG glioma cells, and glioma cells from human patient biopsies exhibited a regulatory volume decrease (RVD). Although astrocytes were not able to completely reestablish their original prechallenge volumes, glioma cells exhibited complete volume recovery, sometimes recovering to a volume smaller than their original volumes (VPost-RVD < Vbaseline). In glioma cells, RVD was largely inhibited by treatment with a combination of Cl− channel inhibitors, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and Cd2+ (VPost-RVD > 1.4*Vbaseline). Volume regulation was also attenuated to a lesser degree by the addition of R-(+)-[(2- n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1 H-inden-5-yl)oxy]acetic acid (DIOA), a known K+-Cl− cotransporter (KCC) inhibitor. To dissect the relative contribution of channels vs. transporters in RVD, we took advantage of the comparatively high temperature dependence of transport processes vs. channel-mediated diffusion. Cooling D54-MG glioma cells to 15°C resulted in a loss of DIOA-sensitive volume regulation. Moreover, at 15°C, the channel blockers NPPB + Cd2+ completely inhibited RVD and cells behaved like perfect osmometers. The calculated osmolyte flux during RVD under these experimental conditions suggests that the relative contribution of Cl− channels vs. transporters to this process is ∼60–70% and ∼30–40%, respectively. Finally, we identified several candidate proteins that may be involved in RVD, including the Cl− channels ClC-2, ClC-3, ClC-5, ClC-6, and ClC-7 and the transporters KCC1 and KCC3a.

Effects of osmotic stresses on isolated rat hepatocytes. II. Modulation of intracellular pH

1990 ◽  
Vol 258 (2) ◽  
pp. G299-G307 ◽  
Author(s):  
D. Gleeson ◽  
J. G. Corasanti ◽  
J. L. Boyer
Keyword(s):  
Intracellular Ph ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Rat Hepatocytes ◽  
Transport Systems ◽  
Disulfonic Acid ◽  
Isolated Rat Hepatocytes ◽  
Intracellular Buffering Capacity ◽  
Volume Decrease

To assess the roles of acid-base transport systems in cell volume regulation in rat hepatocytes, intracellular pH (pHi) was measured in subconfluent monolayers loaded with 2'-7'-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF) after exposure to hypotonic and relative hypertonic media, interventions that stimulate regulatory volume decrease (RVD) and increase (RVI), respectively. During RVD, pHi decreased from 6.98 +/- 0.11 to 6.85 +/- 0.08 in the absence of HCO3- and from 7.26 +/- 0.10 to 7.19 +/- 0.06 in its presence. Omission of Na+ or addition of 1 mM amiloride prevented the decline in pHi. Acute withdrawal or replacement of Na+ in hypotonic medium resulted in a slower rate of fall or recovery in pHi, respectively, than when the same maneuvers were carried out in isotonic medium. In contrast, during RVI, pHi increased from 6.86 +/- 0.11 to 7.15 +/- 0.15 in the absence of HCO3-, a rise in pHi that was also completely abolished by Na+ removal or by 1 mM amiloride. In the presence of HCO3-, the rise in pHi was less marked than in its absence, although net acid efflux was greater because of a greater intracellular buffering capacity. Cl- removal in the presence of HCO3- had no effect on the change in pHi during either RVD or RVI. Perfusion with 0.5 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS) during RVD lowered pHi further and accentuated the subsequent pHi rise seen after the return to isotonic medium. These data suggest that Na(+)-H+ exchange in rat hepatocytes is downregulated during RVD and activated during RVI. Cl(-)-HCO3- exchange does not appear to be involved in hepatocyte volume regulation.

Volume regulation by human lymphocytes: Characterization of the ionic basis for regulatory volume decrease

1982 ◽  
Vol 112 (2) ◽  
pp. 189-196 ◽  
Author(s):  
Roy K. Cheung ◽  
Sergio Grinstein ◽  
Hans-Michael Dosch ◽  
Erwin W. Gelfand
Keyword(s):  
Volume Regulation ◽  
Human Lymphocytes ◽  
Regulatory Volume Decrease ◽  
Ionic Basis ◽  
Volume Decrease

Volume regulation following Na+ pump inhibition in CCT principal cells: apical K+ loss

1990 ◽  
Vol 258 (3) ◽  
pp. F732-F740 ◽  
Author(s):  
K. Strange
Keyword(s):  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
K Channel ◽  
Principal Cells ◽  
Na Pump ◽  
Collecting Tubule ◽  
K Secretion ◽  
K Concentration ◽  
Volume Decrease ◽  
High Conductance

Ouabain caused rabbit cortical collecting tubule (CCT) principal cells to swell 67%. Swollen cells downregulated their volume at a rate of 4%/min to a new volume 16% below control. A qualitatively similar pattern of swelling and volume regulation was observed with peritubular addition of 2.0 microM prostaglandin E2 (PGE2), a putative endogenous Na+ pump inhibitor. Regulatory volume decrease (RVD) in ouabain-swollen cells was inhibited 50-70% by bilateral addition of 2.0 mM Ba2+ or 5.0 mM TEA+. Peritubular TEA+ had no effect on RVD. Luminal addition of 5.0 mM TEA+ or 0.2 mM quinidine inhibited RVD 50-60%, suggesting involvement of an apical K+ channel. This channel appeared to be distinct from the resting apical K+ conductance. Replacement of cellular K+ with Rb+, which is commonly used as a tracer of K+ secretion in the CCT, had little effect on the rate and magnitude of ouabain swelling but inhibited RVD 50-60%. A 10-fold elevation of luminal K+ before ouabain or after completion of RVD caused principal cells to swell 10% and 31%, respectively. In control cells, this K(+)-induced swelling was unaffected by the presence of 1.0 mM quinidine in the perfusate and could be mimicked by elevation of Rb+ instead of K+ concentration. The magnitude of swelling in volume-regulated principal cells, however, was reduced 50-60% by the presence of luminal quinidine or by luminal addition of Rb+ instead of K+. The putative apical RVD K+ channel may be similar to high-conductance K+ channels described in principal cell patch-clamp studies from other laboratories.

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