Effects of dibutyryl cyclic AMP on Na+,K(+)-ATPase activity and intracellular Na+ and K+ in primary cultures of astrocytes from DBA and C57 mice.
Effects of chronic treatment of dibutyryl cyclic AMP (db-cyclic AMP) on Na+,K(+)-ATPase activity in cell homogenates and intracellular Na+ and K+ contents [(Na+)i and (K+)i] were studied in primary cultures of astrocytes derived from cerebral cortex of neonatal audiogenic seizure-susceptible DBA and audiogenic seizure-resistant C57 mice. Na+,K(+)-ATPase activity in cell homogenates was greater and (Na+)i was less in DBA astrocytes than in C57 astrocytes. There was no difference in (K+)i between astrocytes from DBA and C57 mice. Addition of db-cyclic AMP to the medium from day 14 to day 21 in culture (final concentration 0.25 mM) increased Na+,K(+)-ATPase activity in cell homogenates and decreased (Na+)i, but had no significant effect on (K+)i in astrocytes from either DBA or C57 mice. Chronic treatment with db-cyclic AMP altered cell growth. Protein and DNA content of cultured astrocytes from both DBA and C57 mice was decreased. DNA was more affected than protein. Modifying K+ and Na+ concentration in medium altered Na+,K(+)-ATPase activity in cell homogenates as well as (Na+)i and (K+)i in cultured astrocytes of both DBA and C57 mice. Changes in (Na+)i and (K+)i at different K+ concentrations in medium paralleled those in Na+,K(+)-ATPase activity in cell homogenates. Results indicate that the ability to transport Na+ across the cell membrane and the response of Na+,K(+)-ATPase to db-cyclic AMP and to the changes in K+ in medium of cultured astrocytes from audiogenic seizure-susceptible DBA mice are sufficient.
Li
J
J
Department of Physiology, University of Utah School of Medicine, Salt Lake City.
Chow
S Y
SY
D000161:Acoustic Stimulation; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology*; D002478:Cells, Cultured; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D011188:Potassium / Q000378:metabolism*; D012640:Seizures / Q000209:etiology / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D003994:Bucladesine; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium