Morphological plasticity of cultured astrocytes derived from the subfornical organ of the adult rat

The morphological plasticity of astrocytes from the subfornical organ of the adult rat has been examined using an explant culture preparation. Astrocytes migrate out of the explant and form a monolayer of amorphous, non-stellate cells. This non-stellate form was maintained when cultures were incubated in a HEPES buffered salt solution (HBSS) for 50 minutes. The fraction of cells that was stellate in these cultures was significantly increased when cultures were incubated in HBSS supplemented with forskolin (5 M; but not 1,9-dideoxyforskolin) or with nitroprusside (10–100M)indicating that elevation of intracellular cAMP or cGMP mediates stellation. The stellation responses induced by forskolin and by nitroprusside were blocked by inclusion of serum (0.5%) or of LY83,583 (10M), an inhibitor of soluble guanylate cyclase, in the incubation medium. The relevance of the data to neuroglial plasticity in the subfornical organ in vivo is discussed.