Summary
The surface charge of isolated rat dorsal root ganglion neurones was studied by microelectrophoresis technique. The increase of Ca concentration caused greater reduction of the electrophoretic mobility compared to that produced by an equivalent amount of divalent organic cations, dimethonium or hexamethonium. No charge reversal for Ca concentrations up to 80 mM was observed. These data fit the suggestion that two anion groups of the outer membrane surface can bind one Ca ion with apparent binding constant of about 50 M−1. In solutions of low pH the electrophoretic mobility of cells decreased corresponding to titration of acidic groups with apparent pK=4.2. Trypsin treatment in mild conditions markedly reduced the surface charge: however, neuraminidase and hyaluronidase did not change it. N-bromosuccinimide (a specific reagent for carboxylic groups of proteins) decreased the electrophoretic mobility about 60%. However, no increase of the surface charge after the action of specific reagents for amino groups (2,4,6-trinitrobenzenesulfonic acid and maleic anhydride) was observed. It was shown that the surface charge depends also on the intracellular metabolism. If 1 mM dibutyryl cAMP or theophilline was added to the culture medium (thus, raising the concentration of cAMP inside the cell) the surface charge increased. This effect developed slowly and reached its maximum on the third day of incubation. Treatment of cells by 5 mM tolbutamide (an inhibitor of some protein kinases) did not change cell mobility. Addition of 5 mM N-ethylmaleimide (an inhibitor of adenylate cyclase) to the culture medium produced some decrease of the surface charge. On the basis of data obtained it is suggested that the charge of the outer membrane surface of neurones studied is mainly determined by carboxylic groups of membrane proteins, and changes in intracellular cAMP concentration influence the synthesis and reconstruction of these membrane components.
Similar content being viewed by others
References
Alvarez, O., Brodwick, M., Latorre, R., McLaughlin, A., McLaughlin, S., Szabo, G. 1983. Large divalent cations and electrostatic ptoentials adjacent to membranes. Experimental results with hexamethonium.Biophys. J. 44:333–342
Bolognani, L., Masserini, M., Bodimi, P.A., Bolognani, F.A.M., Ottaviani, E. 1981. Lipid composition in ganglia of mollusca.J. Neurochem. 36:821–825
Dolgaya, E.V., Mironov, S.L., Pogorelaya, N.Ch. 1984. The surface charge of murine neuroblastoma cells during their growth and morphological differentiation.Neirofiziologya (Kiev) 17:168–174
Haydon, D.A., Seaman, G.V.F. 1967. Electrokinetic studies on the ultrastructure of human erythrocyte.Arch. Biochem. Biophys. 122:126–135
Henry, D.G. 1938. A source of error in micro-cataphoretic measurements with a cyclindrical-bore cell.J. Chem. Soc. (1938) pp. 997–999
Kanamori, I., Hayakawa, T.L., Nagatsu, T. 1976. Characterization of protein kinases from bovine parotid glands. The effect of tolbutamide and its derivatives on these partially purified enzymes.Biochim. Biophys. Acta 429:147–162
McLaughlin, S., Mulrine, N., Gresalfi, T., Vio, G., McLaughlin, A. 1981. Adsorption of divalent cations to bilayer membranes containing phosphatidylserine.J. Gen. Physiol. 77:445–473
Means, G.E., Feeny, R.E. 1971. Chemical Modification of Proteins. Holden-Day, San Francisco
Rasmussen, H., Goodman, D.B.P. 1977. Relationships between calcium and cyclic nucleotides in cell activation.Physiol. Rev. 57:421–509
Reilly, T.M., Blecher, M. 1983. On the mechanism of isoproterenol-induced desensitization of adenylate cyclase in cultured differentiated hepatocytes.Biochim. Biophys. Acta 720:126–132
Seaman, G.V.F., Heard, D.H. 1960. The surface of a washed human erythrocyte as a polyanion.J. Gen. Physiol. 44:251–272
Seaman, G.V.F., Vassar, P.S., Kendal, M.J. 1969. Electrophoretic studies of human polynuclear leukocytes and erythrocytes: The binding of calcium ions within the peripheral regions.Arch. Biochem. Biophys. 135:356–363
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Mironov, S.L., Dolgaya, E.V. Surface charge of mammalian neurones as revealed by microelectrophoresis. J. Membrain Biol. 86, 197–202 (1985). https://doi.org/10.1007/BF01870598
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01870598