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) me re examined. The cells stably overexpressing APP contained higher amou nt of GTP binding protein Go and cytosolic inactive protein kinase C e psilon, and showed less Ca2+ influx through muscarinic acetylcholine r eceptor ml compared to original and mock cells which had been transfec ted with a vector alone. The contents of sn-1, 2-diacylglycerol and cy cilc AMP were also reduced in the APP transfectants, although the simi lar changes were observed in the mock cells. These findings strongly s uggest that the overexpression of APP affect the transient receptor-me diated ion channel and calcium-related cell metabolisms in neuronal ce lls.