Sodium and potassium uptake in primary cultures of rat astroglial cells induced by long-term exposure to the basic astroglial growth factor (AGF2).

Astroglial cell cultures were derived from newborn rat forebrain and cultured for 5 days in serum containing-, and for an additional 4 days in a serum-free, defined medium. At the end of this 9-day-long period, basic astroglial growth factor (AGF2) was administered to the culture medium (10 ng per ml). Cells were subsequently cultured in AGF2 containing serum-free, defined medium for further two weeks. At definite intervals of culturing, unidirectional influx of both Na+ and K+ (INa and IK, respectively) was determined by applying 22Na and 42K. The AGF2-treated cultures showed highly increased, amiloride-sensitive INa at the early exposure period (2-8 hours), similar to that we have reported about cultured astroglia exposed to AGF2 for minutes. They also exhibited significant furosemide-sensitive-, while relatively poor ouabain-sensitive component of INa. However, at later periods of exposure to AGF2, INa was significantly reduced, particularly due to the decrease of its amiloride-sensitive component, while its furosemide-sensitive component further increased with the time of AGF2 treatment. In contrast to INa, the IK in the cultures exposed to AGF2 increased significantly in the course of the long-term exposure period, particularly the ouabain-, and furosemide-sensitive-components, while its amiloride-sensitive component, similarly to that of INa, decreased.(ABSTRACT TRUNCATED AT 250 WORDS)