Remote astroglial response associated with synaptic degeneration results in a net increase of perisynaptic glial fibrillary acidic protein.

Remote astroglial response was evoked in the adult rat visual cortex by unilateral destruction of the corpus geniculatum laterale. Homogenates of ipsi- and contralateral (operated and control) visual cortices were analysed by immunoblotting. A peak increase in glial fibrillary acidic protein (GFAP) was observed 2 weeks after lesion which then declined but did not return to normal showing a time course similar to that of previously observed immunohistochemical changes. Findings prove that the mechanism underlying the enhanced immunoreactivity during remote astroglial response is an up-regulation of GFAP synthesis in the astroglial processes surrounding degenerating synapses.