Long-term astroglial reaction to serotonergic fiber degeneration.

Glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS) expression were analysed by Western and Northern blotting in the hippocampus, the frontal and occipital cortex, and the cerebellum of the adult rat, as a manifestation of the astroglial reaction, 2 and 3 months after 5,7-dihydroxytryptamine injection into the lateral ventricule. 5HT injury stimulated GFAP and GS expression in a temporally and regionally specific fashion. At 2 months postlesion, the GFAP-mRNA and GFAP levels appeared enhanced but returned to control levels at 3 months. The GFAP-mRNA and GS-mRNA levels increased in the frontal cortex at 3 months. Such a delayed astroglial reactivity might implicate astrocytes in neurodegenerative disorders.