The effect of aluminum on markers for synaptic neurotransmission, cyclic AMP, and neurofilaments in a neuroblastoma × glioma hybridoma (NG108-15)

The effects of the neurotoxin aluminum on markers of synaptic neurotransmission, adenosine 3′,5′-monophosphate, and neurofilaments have been evaluated in a neuroblastoma × glioma hybridoma (NG108-15). Cells were exposed for 4 days to 2 mM aluminum lactate, a concentration that did not suppress growth. Compared to controls, the activity of choline acetyltransferase was significantly increased by 37% associated with an up-regulation in enzyme activity (V_max). Muscarinic receptors, measured by [³H]QNB binding, were reduced by 41%. In contrast, the activities of acetylcholinesterase and glutamate decarboxylase were not significantly changed. Aluminum raised the level of cyclic AMP by 20%, although adenylate cyclase activity was unchanged. Small amounts of both phosphorylated and non-phosphorylated neurofilaments were detected in NG108-15 cells. Aluminum intoxication, however, did not alter the quantity, ultrastructure, or immunoreactivity of neurofilaments. Our results demonstrate the capability of aluminum to produce selected changes in cholinergic markers and levels of cyclic AMP in a rapidly dividing cell line.