THE DECREMENT OF MUSCARINIC RECEPTOR-MEDIATED CALCIUM INFLUX BY OVEREXPRESSION OF APP IN A MOUSE CHOLINERGIC CELL-LINE

The effects of beta-amyloid precursor protein (APP) overexpressing on cell metabolisms of cholinergic neuronal hybridoma cell line (SN49) mere examined. The cells stably overexpressing APP contained higher amount of GTP binding protein Go and cytosolic inactive protein kinase C epsilon, and showed less Ca2+ influx through muscarinic acetylcholine receptor ml compared to original and mock cells which had been transfected with a vector alone. The contents of sn-1, 2-diacylglycerol and cycilc AMP were also reduced in the APP transfectants, although the similar changes were observed in the mock cells. These findings strongly suggest that the overexpression of APP affect the transient receptor-mediated ion channel and calcium-related cell metabolisms in neuronal cells.