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Water and Electrolyte Contents, Cell pH, and Membrane Potential of Primary Cultures of Astrocytes from DBA, C57, and SW Mice
Author(s) -
Chow SenYao,
Li Jun,
Woodbury Dixon M.
Publication year - 1992
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/j.1528-1157.1992.tb01683.x
Subject(s) - astrocyte , bumetanide , intracellular , chemistry , microbiology and biotechnology , ouabain , neuroglia , intracellular ph , sodium , biophysics , biochemistry , ion transporter , nuclear chemistry , membrane , endocrinology , biology , central nervous system , organic chemistry
Summary: Some basic properties of primary cultures of astrocytes derived from the cerebral cortex of an audiogenic seizure‐sensitive strain of mice, DBA/2J (DBA), were studied with different approaches. The results were compared with those of audiogenic seizure‐resistant strains, C57BL/6J (C57) and Swiss Webster (SW). Contents of intracellular water, protein, and DNA of DBA astrocytes were 0.673 ± 0.019 ml/g cells, 0.082 ± 0.006 g/g cells, and 0.0072 ± 0.0005 g/g cells, respectively. These results are not different from those of either C57 or SW astrocytes. Intracellular concentration of K + , Na + , and Cl − ([K + ] 1 , [Na + ] 1 , and [Cl − ] 1 ) derived from the flame photometric and from the radioisotope uptake data of DBA astrocytes were 120.4 ± 8.5,25.9 ± 3.2, and 26.8 ± 1.8 mM/L cell H 2 O, respectively. [Na + ] 1 and [Cl − ] 1 in DBA astrocytes were lower than those in C57 and SW astrocytes. In DBA astrocytes, SITS decreased the cell/ medium ratio (C/M) of 36 Cl − and increased the C/M of 125 I − ; ouabain increased the C/M of 22 Na + and decreased the C/M of 125 I − ; bumetanide decreased the C/M of both 36 Cl − and 22 Na + ; and NaClO 4 decreased the C/M of 125 I − . Similar results were observed in both C57 and SW astrocytes. Intracellular pH (pH i ) as determined with 14 C‐DMO of astrocytes in HEPES‐buffered saline solution averaged 7.04 ± 0.03 for DBA, 7.01 ± 0.02 for C57, and 6.97 ± 0.02 for SW mice when pH of medium was maintained at 7.4. Modification of ion (HCO 3 ‐, Cl − , Na + , and K + ) concentration and pH of culture medium all changed the pH i of astrocytes. Membrane potential as derived from the distribution of Tl‐204 in cells of DBA astrocytes was ‐78.2 ± 1.8 mV, lower than that of C57 and SW astrocytes. In cultured astrocytes of these three strains of mice, membrane potential was correlated with K + of medium [K + ] o between 1.2 and 90 mM. A 10‐fold increase in [K + ] o depolarized the astrocytes by ∼54–58 mV. The results of this study demonstrate that primary cultures of astrocytes derived from the cerebral cortex of DBA mice have biochemical and biophysical properties similar to those of the C57 and SW mice except that they have slightly lower membrane potentials despite lower concentrations of [Na + ] 1 and [Cl − ] 1 . Their responses to various transport inhibitors and environmental changes of electrolytes are similar.