Amyloid beta protein does not interact with tachykinin receptors coupled to inositol phospholipid hydrolysis in human astrocytoma cells.

We have tested the interaction between amyloid beta protein (A beta P) and tachykinin receptors in cultured UC-11MG astrocytoma cells, which express high affinity substance P receptors and respond to substance P with an unusually large stimulation of polyphosphoinositide hydrolysis. Both the full-length A beta P (A beta P1-40) and the fragment 25-35 (A beta P25-35) did not affect the stimulation of [3H]inositolmonophosphate (InsP) formation by substance P. A beta P25-35 was also inactive when applied to the cultures 18 or 72 h prior to the assay. In addition, A beta P25-35 did not displace specifically bound [3H]SarMet substance P from its recognition sites in intact UC-11MG cells. These results suggest that, at least in this specific cell type, amyloid peptides do not interact with substance P receptors.