Figure 1.

Effects of NE and propranolol on the expression of cell-associated APP. Confluent monolayers of astrocytes were incubated for 24 h in serum-free media containing 50 μM NE. (A) Representative immunoblot with mAb 22C11 shows that astrocytes incubated with NE (50 μM) contained significantly more cell-associated APP than untreated cells, and that this increase was inhibited by propranolol (Prop, 50 μM). This experiment was replicated with similar results. (B) Representative Northern blot indicates that either 50 or 100 μM NE was equally effective in stimulating APP mRNA levels above those of controls (Con), and that this effect was mimicked by isoproterenol (Iso, 50 μM). G3PDH mRNA, used as a control for RNA loading, was not affected by drug treatments. (C) The stimulatory effect of NE or isoproterenol on APP mRNA synthesis was significantly inhibited by propranolol (∗, P < 0.05). The graph represents means and SEM obtained from three independent experiments.