BETA-AMYLOID INCREASES ENZYME-ACTIVITY AND PROTEIN-LEVELS OF GLUTAMINE-SYNTHETASE IN CULTURED ASTROCYTES

Previous studies have reported that beta-amyloid peptides induce prope rties of reactivity in cultured astrocytes, We report here that aggreg ated A beta peptides increase expression of the enzyme glutamine synth etase in cultured astrocytes, as assessed by enzyme assay, Western blo t analysis, and immunocytochemistry. The enhanced enzyme levels occur gradually over a period of 4 days after A beta exposure and maintain p eak values for at least several days thereafter. These data suggest th at A beta-related reactive astrocytosis in Alzheimer's disease brain m ay benefit local neurons by enhancing glial capacity to regulate level s of the excitotoxin glutamate. (C) 1996 Academic Press, Inc.