scholarly journals TRPV4 Contributes to Resting Membrane Potential in Retinal Müller Cells: Implications in Cell Volume Regulation

2017 ◽  
Vol 118 (8) ◽  
pp. 2302-2313 ◽  
Author(s):  
Vanina Netti ◽  
Juan Fernández ◽  
Maia Kalstein ◽  
Alejandro Pizzoni ◽  
Gisela Di Giusto ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Cell Volume ◽  
Volume Regulation ◽  
Cell Volume Regulation ◽  
Müller Cells ◽  
Resting Membrane Potential ◽  
Muller Cells

scholarly journals Cell Volume Regulation in Cultured Human Retinal Müller Cells Is Associated with Changes in Transmembrane Potential

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e57268 ◽  
Author(s):  
Juan M. Fernández ◽  
Gisela Di Giusto ◽  
Maia Kalstein ◽  
Luciana Melamud ◽  
Valeria Rivarola ◽  
...  
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Transmembrane Potential ◽  
Cell Volume Regulation ◽  
Müller Cells ◽  
Muller Cells

scholarly journals Release of taurine and glutamate contributes to cell volume regulation in human retinal Müller cells: differences in modulation by calcium

2018 ◽  
Vol 120 (3) ◽  
pp. 973-984 ◽  
Author(s):  
Vanina Netti ◽  
Alejandro Pizzoni ◽  
Martha Pérez-Domínguez ◽  
Paula Ford ◽  
Herminia Pasantes-Morales ◽  
...  
Keyword(s):  
Cell Volume ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Müller Cells ◽  
Anion Channel ◽  
Müller Cell ◽  
Regulatory Mechanisms ◽  
Muller Cells ◽  
Muller Cell ◽  
Volume Decrease

Neuronal activity in the retina generates osmotic gradients that lead to Müller cell swelling, followed by a regulatory volume decrease (RVD) response, partially due to the isoosmotic efflux of KCl and water. However, our previous studies in a human Müller cell line (MIO-M1) demonstrated that an important fraction of RVD may also involve the efflux of organic solutes. We also showed that RVD depends on the swelling-induced Ca2+ release from intracellular stores. Here we investigate the contribution of taurine (Tau) and glutamate (Glu), the most relevant amino acids in Müller cells, to RVD through the volume-regulated anion channel (VRAC), as well as their Ca2+ dependency in MIO-M1 cells. Swelling-induced [3H]Tau/[3H]Glu release was assessed by radiotracer assays and cell volume by fluorescence videomicroscopy. Results showed that cells exhibited an osmosensitive efflux of [3H]Tau and [3H]Glu (Tau > Glu) blunted by VRAC inhibitors 4-(2-butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl)-oxybutyric acid and carbenoxolone reducing RVD. Only [3H]Tau efflux was mainly dependent on Ca2+ release from intracellular stores. RVD was unaffected in a Ca2+-free medium, probably due to Ca2+-independent Tau and Glu release, but was reduced by chelating intracellular Ca2+. The inhibition of phosphatidylinositol-3-kinase reduced [3H]Glu efflux but also the Ca2+-insensitive [3H]Tau fraction and decreased RVD, providing evidence of the relevance of this Ca2+-independent pathway. We propose that VRAC-mediated Tau and Glu release has a relevant role in RVD in Müller cells. The observed disparities in Ca2+ influence on amino acid release suggest the presence of VRAC isoforms that may differ in substrate selectivity and regulatory mechanisms, with important implications for retinal physiology. NEW & NOTEWORTHY The mechanisms for cell volume regulation in retinal Müller cells are still unknown. We show that swelling-induced taurine and glutamate release mediated by the volume-regulated anion channel (VRAC) largely contributes the to the regulatory volume decrease response in a human Müller cell line. Interestingly, the hypotonic-induced efflux of these amino acids exhibits disparities in Ca2+-dependent and -independent regulatory mechanisms, which strongly suggests that Müller cells may express different VRAC heteromers formed by the recently discovered leucine-rich repeat containing 8 (LRRC8) proteins.

scholarly journals Cell volume regulation: the role of taurine loss in maintaining membrane potential and cell pH

2000 ◽  
Vol 523 (1) ◽  
pp. 147-154 ◽  
Author(s):  
H. Guizouarn ◽  
R. Motais ◽  
F. Garcia‐Romeu ◽  
F. Borgese
Keyword(s):  
Membrane Potential ◽  
Cell Volume ◽  
Volume Regulation ◽  
Cell Volume Regulation ◽  
Cell Ph

scholarly journals Volume regulation by Amphiuma red blood cells. The membrane potential and its implications regarding the nature of the ion-flux pathways.

1980 ◽  
Vol 76 (6) ◽  
pp. 683-708 ◽  
Author(s):  
P M Cala
Keyword(s):  
Membrane Potential ◽  
Alkali Metal ◽  
Red Blood Cells ◽  
Cell Volume ◽  
Blood Cells ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Ion Flux ◽  
Regulatory Response

After osmotic perturbation, the red blood cells of Amphiuma exhibited a volume-regulatory response that returned cell volume back to or toward control values. After osmotic swelling, cell-volume regulation (regulatory volume decrease; RVD) resulted from net cellular loss of K, Cl, and osmotically obliged H2O. In contrast, the volume-regulatory response to osmotic shrinkage (regulatory volume increase; RVI) was characterized by net cellular uptake of Na, Cl, and H2O. The net K and Na fluxes characteristic of RVD and RVI are increased by 1-2 orders of magnitude above those observed in studies of volume-static control cells. The cell membrane potential of volume-regulating and volume-static cells was measured by impalement with glass microelectrodes. The information gained from the electrical and ion-flux studies led to the conclusion that the ion fluxes responsible for cell-volume regulation proceed via electrically silent pathways. Furthermore, it was observed that Na fluxes during RVI were profoundly sensitive to medium [HCO3] and that during RVI the medium becomes more acid, whereas alkaline shifts in the suspension medium accompany RVD. The experimental observations are explained by a model featuring obligatorily coupled alkali metal-H and Cl-HCO3 exchangers. The anion- and cation-exchange pathways are separate and distinct yet functionally coupled via the net flux of H. As a result of the operation of such pathways, net alkali metal, Cl, and H2O fluxes proceed in the same direction, whereas H and HCO3 fluxes are cyclic. Data also are presented that suggest that the ion-flux pathways responsible for cell-volume regulation are not activated by changes in cell volume per se but by some event associated with osmotic perturbation, such as changes in intracellular pH.

Mechanisms responsible for cell volume regulation during hyperkalemic cardioplegic arrest

2000 ◽  
Vol 70 (2) ◽  
pp. 633-638
Author(s):  
Xiwu Sun ◽  
Christopher T Ducko ◽  
Eric M Hoenicke ◽  
Karen Reigle ◽  
Ralph J Damiano
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Cell Volume Regulation ◽  
Cardioplegic Arrest
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