Summary
The resting membrane potential of the cultured fibroblasts derived from rabbit subcutaneous tissues was −10.2±0.20 mV (n=390). This potential was affected by the potassium concentration in the culture medium, but not by other chemical or hormonal preparations, such as dibutyryladenosine 3′,5′-cyclic monophosphate (0.5 to 5.0 mmol/l), sodium fluoride (10−5 to 10−4 M), hydrocortisone (10−7 to 10−6 M), parathyroid extract (0.5 to 1.0 U/ml), or thyrotrophin (5 to 10 mU/ml). The Na+, K+, and Cl− concentrations of the cultured fibroblasts were 35.4, 85.7, and 22.6 mmol/l cell water, respectively. The water and protein contents of these cells were 82.1 and 9.18 g/100-g cells, respectively. The intracellular pH of fibroblasts as determined by [14C] dimethyloxazolidine-2, 4-dione, and3H2O ranged between 6.9 and 7.1 when the pH of the culture medium was maintained at 7.4. The activiities of Na+, K+-, HCO3 −-, and Ca++, Mg++-ATPases in these cultured cells were 19.0±2.1, 13.6±2.1, and 6.6±1.2 nmol pi/mg protein per minute, respectively, and the carbonic anhydrase activity was 0.054 U/mg protein. Calculations based on the values for the membrane potential and the electrolyte concentrations observed in this study indicate that Na+, K+, Cl−, and H+ are not distributed according to their electrochemical gradients across the cell membrane. Na+, Cl−, and H+ are actively transported out of the cells and K+ into the cells.
Similar content being viewed by others
References
Michalopoulos, G.; Pitot, H. C. Primary culture of parenchymal liver cells on collagen synthesis. Exp. Cell Res. 94: 70–78; 1975.
Waddell, W. J.; Butler, T. C. Calculation of intracellular pH from the distribution of 5,5′-dimethyl-2,4-oxazolidinedione (DMO). Application to skeletal muscle of the dog. J. Clin. Invest. 38: 720–729; 1959.
Chow, S. Y.; Yen-Chow, Y. C.; Woodbury, D. M. Effects of thyrotropin, acetazolamide, 4-acetamido-4′-isothiocyanostilbene-2,2′-disulfonic acid, perchlorate, ouabain and furosemide on pH and HCO3 − concentrations in cells and luminal fluid of turtle thyroid as calculated from the distribution of [14C] dimethyloxazolidine-2,4-dione. J. Pharmacol. Exp. Ther. 225: 17–23; 1983.
Bonting, S. L. Sodium-potassium activated adenosine-triphosphatase and ion transport. In: Bittar, E. E., ed. Membranes and ion transport. New York: Wiley-Intersciences; 1970: 257–363.
Kimelberg, H. K.; Bourke, R. S. Properties and localization of bicarbonate stimulated ATPase in rat brain. J. Neurochem. 20: 347–359; 1973.
Tamburini, R.; Albuquerque, E. X.; Daly, J. W.; Kauffman, F. C. Inhibition of calcium dependent ATPase from sarcoplasmic reticulum by a new class of indolizidine alkaloids, pumiliotoxins A, B, and2501D. J. Neurochem. 37: 775–780; 1981.
Maren, T. H. A simplified micromethod for the determination of carbonic anhydrase and its inhibitors. J. Pharmacol. Exp. Ther. 130: 26–29; 1960.
Chow, S. Y.; Kemp, J. W.; Woodbury, D. M. Correlation of iodide transport with Na+, K+-ATPase, HCO3 −-ATPase and carbonic anhydrase activities in different functional states of the rat thyroid gland. J. Endocrinol. 92: 371–379; 1982.
Lowry, O. H.; Rosebrough, W. J.; Farr, A. L.; Randall, R. S. Protein measurement with the Folin phenol reagent. J. Biol. Chem. 193: 265–274; 1951.
Chowdbury, T. K. Effects of concanavalin A on cellular dynamics and membrane transport. Adv. Exp. Med. Biol. 55: 187–206; 1975.
Swift, M. R.; Todaro, G. J. Membrane potentials of human fibroblast strains in culture. J. Cell. Physiol. 71: 61–64; 1968.
Bard, J.; Wright, M. D. The membrane potentials of fibroblasts in different environments. J. Cell Physiol. 84: 141–146; 1975.
Lamb, J. F.; MacKinnon, M. G. A. The membrane potential and permeabilities of the L cell membrane to Na, K and chloride. J. Physiol. 213: 683–689; 1971.
Nelson, P. G.; Peacock, J.; Minna, J. An active electrical response in fibroblasts. J. Gen. Physiol. 60: 58–71; 1972.
Borle, A. B.; Loveday, J. Effects of temperature, potassium, and calcium on the electrical potential difference in HeLa cells. J. Cancer Res. 28: 2401–2405; 1968.
Woodbury, J. W. The cell membrane: ion fluxes and the genesis of the resting potential. In: Ruch, T. C.; Patton, H. D. eds. Physiology and biophysics. Philadelphia: W. B. Saunders Co.; 1982: 37–45.
Lamb, J. F.; MacKinnon, M. G. A. Effect of ouabain and metabolic inhibitors on the Na and K movements and nucleotide contents of L cells. J. Physiol. 213: 665–682; 1971.
Sachs, H. G.; McDonald, T. F. Membrane potentials of BHK (baby hamster kidney) cell line: ionic and metabolic determinants. J. Cell Physiol. 80: 347–358; 1973.
Author information
Authors and Affiliations
Additional information
This study was supported by Grant AM20935 from the NIAMDD, NIH, Bethesda, Maryland, and National Aeronautics & Space Administration NASA-Ames Grant NAG 2-108 and U.S. Department of Energy Contract DE-AC02-76-EV-00119. D. M. W. is the recipient of a Research Career Award (5-K6-NB-13838), NINCDS, NIH.
Rights and permissions
About this article
Cite this article
Yen-Chow, Y.C., Chow, S.Y., Jee, W.S.S. et al. Membrane potentials, electrolyte contents, cell pH, and some enzyme activities of fibroblasts. In Vitro 20, 677–684 (1984). https://doi.org/10.1007/BF02618872
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02618872