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Teulon J, Planelles G, Sepúlveda FV, Andrini O, Lourdel S, Paulais M. Renal Chloride Channels in Relation to Sodium Chloride Transport. Compr Physiol 2018; 9:301-342. [DOI: 10.1002/cphy.c180024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Robson L, Hunter M. Mechanisms underlying regulation of a barium-sensitive K+ conductance by ATP in single proximal tubule cells isolated from frog kidney. J Membr Biol 2005; 204:39-47. [PMID: 16007502 DOI: 10.1007/s00232-005-0745-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Accepted: 03/31/2005] [Indexed: 10/25/2022]
Abstract
K(+) channels play an important role in pump-leak coupling and volume regulation in the renal proximal tubule. Previous experiments have identified a barium-sensitive K(+) conductance (G(Ba)) in proximal tubule cells isolated from frog kidneys. In this paper we examine the regulation of G(Ba) by ATP. G(Ba) was measured in single cells isolated from frog kidney using the whole-cell patch-clamp technique. G(Ba) was activated by 2 mM: intracellular ATP. This activation was enhanced by inhibition of protein kinase C and attenuated by inhibition of protein kinase A, indicating reciprocal regulation by these kinases. Activation by ATP was reduced in the presence of a hypertonic bath solution, suggesting that cell swelling was required. However, after activation to steady-state, G(Ba )was not sensitive to cell-volume changes. Hypotonic shock-induced volume regulation was inhibited by barium and quinidine, inhibitors of G(Ba). The effect of maximal inhibitory concentrations of barium and quinidine on volume regulation was similar and addition of both blockers together did not augment the inhibitory response. G(Ba) was also activated by ADP, via a mechanism dependent on the presence of Mg(2+). However, the responses to ADP and ATP were not additive, suggesting that these nucleotides may share a common mechanism of activation. The regulation of G(Ba) by ATP was biphasic, with a half-maximal activating concentration of 0.89 mM and a half maximal inhibitory concentration of 6.71 mM. The sensitivity to nucleotides suggests that G(Ba) may be regulated by the metabolic state of the cell. Furthermore, the sensitivity to solution osmolality, coupled with the blocker profile of inhibition of volume regulation, suggests that G(Ba) could play a role in volume regulation.
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Affiliation(s)
- L Robson
- Department of Biomedical Science, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN, UK.
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Millar ID, Robson L. Na+-alanine uptake activates a Cl- conductance in frog renal proximal tubule cells via nonconventional PKC. Am J Physiol Renal Physiol 2001; 280:F758-67. [PMID: 11292617 DOI: 10.1152/ajprenal.2001.280.5.f758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hyposmotically induced swelling of frog renal proximal tubule cells activates a DIDS-sensitive, outwardly rectifying Cl- conductance via a conventional protein kinase C (PKC). This study examines whether Na+-alanine cotransport similarly activates a DIDS-sensitive Cl- conductance in frog renal proximal tubule cells. On stimulation of Na+-alanine cotransport, the DIDS-sensitive current (I(DIDS-Ala)) increased markedly over time. I(DIDS-Ala) exhibited outward rectification, a Na+/Cl- selectivity ratio of 0.19 +/- 0.03, and an anion selectivity sequence Br- = Cl- > I- > gluconate-. Activation of I(DIDS-Ala) was dependent on ATP hydrolysis and PKC-mediated phosphorylation and was inhibited by hyperosmotic conditions. Activation could be not ascribed to a conventional PKC isoform, as I(DIDS-Ala) was not affected by removing Ca2+ or by phorbol ester treatment, suggesting a role for a nonconventional PKC isoform, either novel or atypical. We conclude that Na+-alanine cotransport activates a DIDS-sensitive Cl- conductance via a nonconventional PKC isoform. This contrasts with the hyposmotically activated Cl- conductance, which requires conventional PKC activation.
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Affiliation(s)
- I D Millar
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
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Mignen O, Egee S, Liberge M, Harvey BJ. Basolateral outward rectifier chloride channel in isolated crypts of mouse colon. Am J Physiol Gastrointest Liver Physiol 2000; 279:G277-87. [PMID: 10915635 DOI: 10.1152/ajpgi.2000.279.2.g277] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Single channel patch-clamp techniques were used to demonstrate the presence of outwardly rectifying chloride channels in the basolateral membrane of crypt cells from mouse distal colon. These channels were rarely observed in the cell-attached mode and, in the inside-out configuration, only became active after a delay and depolarizing voltage steps. Single channel conductance was 23.4 pS between -100 and -40 mV and increased to 90.2 pS between 40 and 100 mV. The channel permeability sequence for anions was: I(-) > SCN(-) > Br(-) > Cl(-) > NO(3)(-) > F(-)>> SO(4)(2-) approximately gluconate. In inside-out patches, the channel open probability was voltage dependent but insensitive to intracellular Ca(2+) concentration. In cell-attached mode, forskolin, histamine, carbachol, A-23187, and activators of protein kinase C all failed to activate the channel, and activity could not be evoked in inside-out patches by exposure to the purified catalytic subunit of cAMP-dependent protein kinase A. The channel was inhibited by 5-nitro-2-(3-phenylpropylamino)benzoate, 9-anthracenecarboxylic acid, and DIDS. Stimulation of G proteins with guanosine 5'-O-(3-thiotriphosphate) decreased the channel open probability and conductance, whereas subsequent addition of guanosine 5'-O-(2-thiodiphosphate) reactivated the channel.
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Affiliation(s)
- O Mignen
- Centre National de la Recherche Scientifique, Unité de Recherche en Physiologie Cellulaire, Université de Bretagne Occidentale, Brest, France
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Robson L, Hunter M. Stimulation of Na+-alanine cotransport activates a voltage-dependent conductance in single proximal tubule cells isolated from frog kidney. J Physiol 1999; 517 ( Pt 1):193-200. [PMID: 10226159 PMCID: PMC2269323 DOI: 10.1111/j.1469-7793.1999.0193z.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
1. The swelling induced by Na+-alanine cotransport in proximal tubule cells of the frog kidney is followed by regulatory volume decrease (RVD). This RVD is inhibited by gadolinium (Gd3+), an inhibitor of stretch-activated channels, but is independent of extracellular Ca2+. 2. In this study, the whole cell patch clamp technique was utilized to examine the effect of Na+-alanine cotransport on two previously identified volume- and Gd3+-sensitive conductances. One conductance is voltage dependent and anion selective (GVD) whilst the other is voltage independent and cation selective (GVI). 3. Addition of 5 mM L-alanine to the bathing solution increased the whole cell conductance and gave a positive (depolarizing) shift in the reversal potential (Vrev, equivalent to the membrane potential in current-clamped cells) consistent with activation of Na+-alanine cotransport. Vrev shifted from -36 +/- 4.9 to +12.9 +/- 4.2 mV (n = 15). 4. In the presence of alanine, the total whole cell conductance had several components including the cotransporter conductance and GVD and GVI. These conductances were separated using Gd3+, which inhibits both GVD and GVI, and the time dependency of GVD. Of these two volume-sensitive conductances, L-alanine elicited a specific increase in GVD, whereas GVI was unaffected. 5. The L-alanine-induced activation of GVD was significantly reduced when cells were incubated in a hypertonic bathing solution. 6. In summary, in single proximal tubule cells isolated from frog kidney, on stimulation of Na+-alanine cotransport GVD is activated, while GVI is unaffected. Taken with other evidence, this suggests that GVD is activated by cell swelling, consequent upon alanine entry, and may play a role as an anion efflux pathway during alanine-induced volume regulation.
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Affiliation(s)
- L Robson
- Department of Biomedical Sciences, University of Leeds, Leeds LS2 9NQ, UK.
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Diaz RJ, Losito VA, Mao GD, Ford MK, Backx PH, Wilson GJ. Chloride channel inhibition blocks the protection of ischemic preconditioning and hypo-osmotic stress in rabbit ventricular myocardium. Circ Res 1999; 84:763-75. [PMID: 10205144 DOI: 10.1161/01.res.84.7.763] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The objective of this study was to examine the role of chloride (Cl-) channels in the myocardial protection of ischemic preconditioning (IP). Isolated rabbit ventricular myocytes were preconditioned with 10-minute simulated ischemia (SI) and 20-minute simulated reperfusion (SR) or not preconditioned (control). The myocytes then received 180-minute SI or 45-minute SI/120-minute SR. Indanyloxyacetic acid 94 (IAA-94, 10 micromol/L) or 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, 1 micromol/L) was administered before IP or before SI or SI/SR to inhibit Cl- channels. Electrophysiological studies indicate that these drugs, at the concentrations used, selectively abolished Cl- currents activated under hypo-osmotic conditions (215 versus 290 mOsm). IP significantly (P<0.001) reduced the percentage of dead myocytes after 60-minute (30.8+/-1.3%, mean+/-SEM), 90-minute (35.3+/-1.3%), and 120-minute (39.2+/-1.7%) SI compared with controls (44.7+/-1.6%, 54.5+/-1.3%, and 58.9+/-1.8%, respectively) and after 45-minute SI/120-minute SR (36.3+/-0.6%) compared with control (56.6+/-2.2%). Hypo-osmotic stress also produced protection similar to IP. IAA-94 or NPPB abolished the protection of both IP and hypo-osmotic stress. In buffer-perfused rabbit hearts preconditioned with three 5-minute ischemia/10-minute reperfusion cycles given before the 40-minute long ischemia and 60-minute reperfusion, IP significantly (P<0.0001) reduced infarct size (IP+vehicle, 4.7+/-0.9%, versus control+vehicle, 26.6+/-3.3%; mean+/-SEM). Again, IAA-94 or NPPB abolished the protection of IP. Our results implicate Cl- channels in the IP protection of the myocardium against ischemic/reperfusion injury and demonstrate that hypo-osmotic stress is capable of preconditioning cardiomyocytes.
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Affiliation(s)
- R J Diaz
- Divisions of Cardiovascular Research and Pathology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Schmid A, Blum R, Krause E. Characterization of cell volume-sensitive chloride currents in freshly prepared and cultured pancreatic acinar cells from early postnatal rats. J Physiol 1998; 513 ( Pt 2):453-65. [PMID: 9806995 PMCID: PMC2231287 DOI: 10.1111/j.1469-7793.1998.453bb.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
1. In freshly prepared and cultured exocrine pancreatic acinar cells from 5- to 7-day-old rats a chloride-selective membrane conductance could be activated by intracellular application of GTPgammaS (40-100 microM), by application of positive pressure (5 cmH2O) to the pipette interior or by challenging the cells with a hyposmolar bath solution. Hyperosmolar bath solutions inhibited the cell volume-sensitive chloride currents. 2. The anion permeability sequence of the cell volume-sensitive chloride conductance was I- > Cl- approximately Br- > F- > methanesulphonate- > glutamate-. I- had a higher permeability but lower conductance than Cl-. The permeability ratio for Pglutamate/PCl was 0.12. 3. The cell volume-sensitive chloride conductance showed outward rectification. Membrane depolarization to high positive voltages (>= +60 mV) caused a time-dependent decay in outward currents. 4. DIDS (4, 4'-diisothiocyanatostilbene-2,2'-disulphonic acid) and SITS (4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonic acid) reversibly inhibited the cell volume-sensitive chloride current in a voltage-dependent manner. NPPB (5-nitro-2-(3-phenylpropylamino)-benzoic acid), quinidine, quinine and tamoxifen caused voltage-independent current inhibition. 5. Combined fura-2 and whole-cell current measurements showed that activation of the cell volume-sensitive chloride current does not involve cytosolic Ca2+ signals. Furthermore, there is no evidence that Ca2+-activated chloride currents play a significant role in cultured pancreatic acinar cells from 5- to 7-day-old rats. 6. Polymerase chain reaction followed by DNA sequence analysis indicated the presence of mRNA homologous to the ClC-3 chloride channel in pancreatic tissue from 5-day-old rats.
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Affiliation(s)
- A Schmid
- 2. Physiologisches Institut, Universitat des Saarlandes, D-66421 Homburg/Saar,
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Mounfield PR, Robson L. The role of Ca2+ in volume regulation induced by Na+-coupled alanine uptake in single proximal tubule cells isolated from frog kidney. J Physiol 1998; 510 ( Pt 1):145-53. [PMID: 9625873 PMCID: PMC2231028 DOI: 10.1111/j.1469-7793.1998.145bz.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
1. It has been suggested that epithelial cells maintain cell volume and function, in the face of changes in the rate of transepithelial transport, by activation of volume-regulatory pathways. 2. The aim of the following study was to examine directly the effect of an alteration in Na+-coupled alanine transport on cell length in single proximal tubule cells isolated from frog kidney. 3. An optical technique was used to examine the change in cell length induced by 5 mM L-alanine. 4. On addition of L-alanine to the bath there was an initial increase in cell length to a peak value. This was followed by two types of response. In eighteen out of thirty-one cells a typical volume-regulatory response was observed. The remaining cells showed no volume regulation. 5. Volume regulation was not affected by the removal of extracellular Ca2+. The mean degrees of recovery were 159 +/- 21 % (n = 18) and 144 +/- 18 % (n = 8) in the presence and absence of Ca2+, respectively. 6. Volume regulation was inhibited by depletion of intracellular Ca2+ stores, or in the presence of either Gd3+ or DIDS. The mean degrees of regulation were 55.4 +/- 9.2 % (n = 7), 68.2 +/- 18.8 % (n = 7) and 69.1 +/- 14.3 % (n = 7), respectively. 7. The alanine-induced increases in cell length were both stereospecific and Na+ dependent. 8. The evidence suggests that volume regulation induced by Na+-coupled alanine uptake may be dependent on the release of Ca2+ from intracellular stores. This is in contrast to volume regulation induced by hypotonic shock, which appears to require extracellular Ca2+. Results obtained using a hypotonic shock should, therefore, be viewed with caution.
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Affiliation(s)
- P R Mounfield
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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Nilius B, Eggermont J, Voets T, Buyse G, Manolopoulos V, Droogmans G. Properties of volume-regulated anion channels in mammalian cells. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1998; 68:69-119. [PMID: 9481145 DOI: 10.1016/s0079-6107(97)00021-7] [Citation(s) in RCA: 274] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- B Nilius
- KU Leuven, Laboratorium voor Fysiologie, Belgium.
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Lang F, Busch GL, Ritter M, Völkl H, Waldegger S, Gulbins E, Häussinger D. Functional significance of cell volume regulatory mechanisms. Physiol Rev 1998; 78:247-306. [PMID: 9457175 DOI: 10.1152/physrev.1998.78.1.247] [Citation(s) in RCA: 1269] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To survive, cells have to avoid excessive alterations of cell volume that jeopardize structural integrity and constancy of intracellular milieu. The function of cellular proteins seems specifically sensitive to dilution and concentration, determining the extent of macromolecular crowding. Even at constant extracellular osmolarity, volume constancy of any mammalian cell is permanently challenged by transport of osmotically active substances across the cell membrane and formation or disappearance of cellular osmolarity by metabolism. Thus cell volume constancy requires the continued operation of cell volume regulatory mechanisms, including ion transport across the cell membrane as well as accumulation or disposal of organic osmolytes and metabolites. The various cell volume regulatory mechanisms are triggered by a multitude of intracellular signaling events including alterations of cell membrane potential and of intracellular ion composition, various second messenger cascades, phosphorylation of diverse target proteins, and altered gene expression. Hormones and mediators have been shown to exploit the volume regulatory machinery to exert their effects. Thus cell volume may be considered a second message in the transmission of hormonal signals. Accordingly, alterations of cell volume and volume regulatory mechanisms participate in a wide variety of cellular functions including epithelial transport, metabolism, excitation, hormone release, migration, cell proliferation, and cell death.
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Affiliation(s)
- F Lang
- Institute of Physiology, University of Tübingen, Germany
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Carpenter E, Peers C. Swelling- and cAMP-activated Cl- currents in isolated rat carotid body type I cells. J Physiol 1997; 503 ( Pt 3):497-511. [PMID: 9379407 PMCID: PMC1159837 DOI: 10.1111/j.1469-7793.1997.497bg.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. In the whole-cell configuration of the patch clamp technique, isolated rat carotid body type I cells exhibited reversible activation of Cl- currents during cell swelling effected by hypotonic extracellular solutions. 2. Hypotonic solutions evoked outwardly rectifying, non-inactivating currents which showed time-independent activation. The reversal potential (E(rev)) for the hypotonically evoked current was 1.6 +/- 0.6 mV (n = 26). Reduction of extracellular Cl- from 133 to 65.5 mM caused a shift in E(rev) of +14.7 +/- 0.4 mV (n = 5). 3. The swelling-activated Cl- current could not activate when ATP was omitted from the patch pipette or when substituted for the non-hydrolysable ATP analogues 5'-adenylylimidodiphosphate, AMP-PNP (2 mM) or beta, gamma-methylene-adenosine 5'-triphosphate. AMP-PCP (2 mM). The current also failed to activate in the absence of free intracellular Ca2+. 4. The swelling-activated Cl- current was sensitive to blockade by the Cl- channel blockers niflumic acid (300 microM) and 4,4'-diisothiocyanatostilbene-2, 2'-disulphonic acid (DIDS; 200 microM), although the blockade by DIDS was voltage dependent. 5. A similar, non-inactivating, outwardly rectifying Cl- current was evoked by the inclusion of cAMP (200 microM) in the patch pipette. This current could be inhibited by niflumic acid (300 microM), DIDS (200 microM) and hypertonic solutions, and was virtually abolished in the absence of intracellular ATP. 6. In conclusion, carotid body type I cells possess Cl- currents activated by cell swelling and rises in intracellular cAMP concentration. These currents may be involved in cell volume regulation, blood volume and osmolarity regulation and the response of the type I cell to chemostimuli.
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Affiliation(s)
- E Carpenter
- Institute for Cardiovascular Research, University of Leeds, UK.
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