Figure 6.

Effect of cyclosporin A on APPs secretion and on the increase in cell-associated APP caused by 8Br-cAMP. Astrocytes were prepared as in Fig. 1. (A) Representative immunoblot shows that the increase in cell-associated APP caused by 24-h treatment with 8Br-cAMP (250 μM) was suppressed by cotreatment with 1 μM cyclosporin A, which, by itself, had no effect on basal APP levels. Although astrocytes treated with 8Br-cAMP and cyclosporin A appeared to have slightly lower APP levels than untreated cells, this effect was not significant and was not reproduced in subsequent experiments. (B) The increase in cell-associated APP caused by 24-h treatment with 8Br-cAMP (250 μM) was significantly suppressed (∗, P < 0.05) by the three doses of cyclosporin A (1, 5, or 10 μM) tested. Thr graph represents means and SEM of pooled data obtained from four independent experiments.