Gap junction uncoupling of neonatal rat astroglial cultures does not affect their expression of fibroblast growth factor 2.

Fibroblast growth factor (FGF)-2 is expressed by astroglial cells and regulates astroglial proliferation, differentiation, and gap junction communication. We show now that uncoupling of astroglial cells cultured from neonatal rat cortex, striatum and mesencephalon by 18alpha-glycirrhetinic acid (AGA) or arachidonic acid (AA) (demonstrated by intracellular injections of Lucifer Yellow) does affect neither levels of FGF-2 mRNA (investigated by a competitive RT-PCR method), nor protein (as revealed by Western blot analysis). This suggests that expression of FGF-2, which reduces gap junction communication of cortical and striatal astroglial cells [15], is not affected when astroglial cells are uncoupled. Regulation of FGF-2 expression and coupling in astroglial cells are thus not reciprocal suggesting more complex interrelationships between these two important parameters of astroglial cell differentiation.