ASTROCYTOSIS IN WOBBLER MOUSE SPINAL-CORD INVOLVES A POPULATION OF ASTROCYTES WHICH IS GLUTAMINE SYNTHETASE-NEGATIVE

Mice affected by the wobbler mutation are characterized by a muscular atrophy associated with motoneuron degeneration. As soon as the first clinical signs of the disease appear, reactive astrocytes, strongly gl ial fibrillary acidic protein (GFAP)-positive, are observed in the spi nal cord grey matter. They become prevalent at all levels with disease progression. Immunostaining of glutamine synthetase (GS) shows that t hese reactive astrocytes are never GS-positive. The activity and prote in amounts of GS remain normal in wobbler spinal cord although astrocy tosis develops. Thus, gliosis in the wobbler mouse seems to involve a subpopulation of astrocytes, which is strongly GFAP-positive but GS-ne gative.