Abstract
Cellular element concentrations and dry weight contents in A6 cells were determined using electron microprobe analysis to establish whether these cells exhibit a regulatory volume increase (post-RVD-RVI) when re-establishing isotonicity following a hypotonically induced regulatory volume decrease (RVD). Hypotonic stress was induced by reducing basolateral [NaCl], and hence, osmolarity fell from 260 to 140 mosmol/l. The alterations in cell volume after re-establishing isotonicity, calculated from the cellular dry weight changes, indicate within the first 2 min cell shrinkage from 120 to 76% of control, compatible with almost ideal osmometric behaviour of A6 cells, and thereafter a post-RVD-RVI to 94%. The cellular uptake of osmolytes necessary to explain the post-RVD-RVI could be accounted for solely by a gain in cellular K and Cl. The involvement of a Na-K-2Cl cotransporter in most of the KCl uptake seems plausible since basolateral bumetanide blocked KCl uptake and post-RVD-RVI. The net uptake of cations (K uptake of 185.2, Na loss of 8.2 mmol/kg dry wt) during the isotonic period exceeded the Cl uptake by 38.2 mmol/kg dry wt, suggesting the uptake of another anion and/or the alteration of cellular buffer capacity. The relatively low Na concentration maintained during the isotonic period (13.3 vs. 20.4 mmol/kg wet wt under control conditions) might favour electrolyte uptake via the Na-K-2Cl cotransporter.
Similar content being viewed by others
References
Banderali U, Ehrenfeld J (1996) Heterogeneity of volume-sensitive chloride channels in basolateral membranes of A6 epithelial cells in culture. J Membr Biol 154:23–33
Bauer R, Rick R (1978) Computer analysis of X-ray spectra (EDS) from thin biological specimens. X-Ray Spectrom 7:63–69
Brochiero E, Banderali U, Lindenthal S, Raschi C, Ehrenfeld J (1995) Basolateral membrane chloride permeability of A6 cells: implication in cell volume regulation. Pflugers Arch 431:32–45
Broillet MC, Horisberger JD (1991) Basolateral membrane potassium conductance of A6 cells. J Membr Biol 124:1–12
Civan MM, Shporer M (1989) Physical state of cell Na. Curr Topics Membr Transp 34:1–19
Crowe WE, Ehrenfeld J, Brochiero E, Wills NK (1995) Apical membrane sodium and chloride entry during osmotic swelling of renal (A6) epithelial cells. J Membr Biol 144:81–91
De Smet P, Simaels J, Declercq PE, Van Driessche W (1995) Regulatory volume decrease in cultured kidney cells (A6): role of amino acids. J Gen Physiol 106:525–542
De Smet P, Simaels J, Van Driessche W (1995) Regulatory volume decrease in a renal distal tubular cell line (A6). I. Role of K+ and Cl−. Pflugers Arch 430:936–944
De Smet P, Li J, Van Driessche W (1998) Hypotonicity activates a lanthanide-sensitive pathway for K+ release in A6 epithelia. Am J Physiol 275:C189–C199
Dörge A, Rick R, Gehring K, Thurau K (1978) Preparation of freeze-dried cryosections for quantitative X-ray microanalysis of electrolytes in biological soft tissues. Pflugers Arch 373:85–97
Ehrenfeld J, Raschi C, Brochiero E (1994) Basolateral potassium membrane permeability of A6 cells and cell volume regulation. J Membr Biol 138:181–195
Freedman JC, Hoffman JF (1979) The relation between dicarbocyanine dye fluorescence and the membrane potential of human red blood cells set at varying Donnan equilibria. J Gen Physiol 74:187–212
Grosse T, Heid I, Simaels J, Beck FX, Nagel W, Van Driessche W, Dörge A (2001) Changes in element composition of A6 cells following hypotonic stress. Pflugers Arch 442:297–303
Hall AC, Bush PG (2001) The role of swelling-activated taurine transport pathways in the regulation of chondrocyte volume. Pflugers Arch 442:771–781
Hoffmann EK (1983) Volume regulation by animal cells. Semin Ser Soc Exp Biol 17:55–80
Hoffmann EK, Dunham PB (1995) Membrane mechanisms and intracellular signaling in cell volume regulation. Int Rev Cytol 161:173–262
Hougaard C, Jørgensen F, Hoffmann EK (2001) Modulation of the volume-sensitive K+ current in Ehrlich ascites tumour cells by pH. Pflugers Arch 442:622–631
Lewis SA, Donaldson P (1990) Ion channels and cell volume regulation: chaos in an organized system. News Physiol Sci 5:112–119
Lytle C, McManus T (2002) Coordinate modulation of Na-K-2Cl cotransport and K-Cl cotransport by cell volume and chloride. Am J Physiol 283:C1422–C1431
Matthews JB, Smith JA, Mun EC, Sicklick JK (1998) Osmotic regulation of intestinal epithelia Na+-K+-Cl− cotransport: role of Cl− and F-actin. Am J Physiol 274:C697–C706
Niisato N, Marunaka Y (1999) Activation of Na+-K+-pump by hypoosmolality through tyrosine kinase-dependent Cl− conductance in Xenopus renal epithelial A6 cells. J Physiol (Lond) 518.2:417–432
Rick R, Dörge A, Thurau K (1982) Quantitative analysis of electrolytes in frozen dried sections. J Microsc 125:239–247
Ussing HH (1982) Pathways for transport in epithelia. In: Corrandino RA (ed) Functional regulation at the cellular and molecular levels. Elsevier/North-Holland, Amsterdam, pp 285–297
Van Driessche W, De Smet P, Raskin G (1993) An automatic monitoring system for epithelial cell height. Pflugers Arch 425:164–171
Van Driessche W, De Smet P, Li J, Allen S, Zizi M, Mountian I (1997) Isovolumetric regulation in a distal nephron cell line (A6). Am J Physiol 272:C1890–C1898
Wehner F, Olsen H, Tinel H, Kinne-Saffran E, Kinne RK (2003) Cell volume regulation: osmolytes, osmolyte transport, and signal transduction. Rev Physiol Biochem Pharmacol (in press)
Acknowledgements
The work was supported by grants from the Deutsche Forschungsgemeinschaft.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Grosse, T., Heid, I., Öztürk, I. et al. Recovery of cell volume and electrolytes of A6 cells after re-establishing isotonicity following hypotonic stress. Pflugers Arch - Eur J Physiol 447, 29–34 (2003). https://doi.org/10.1007/s00424-003-1139-3
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00424-003-1139-3