Involvement of M1-muscarinic acetylcholine receptors, protein kinase C and mitogen-activated protein kinase in the effect of huperzine A on secretory amyloid precursor protein-alpha

Abstract

This study is to explore the involvement of muscarinic acetylcholine receptors/protein kinase C cascade and the mitogen-activated protein kinase pathway in the effect of huperzine A on the secretory amyloid precursor protein-alpha. Upregulation of secretory amyloid precursor protein-alpha by huperzine A was attenuated by muscarinic acetylcholine receptor antagonist (specifically by M1-muscarinic acetylcholine receptor antagonist), and markedly blocked (-37.7%) by protein kinase C inhibitor as well. Meanwhile, huperzine A can activate the phosphorylation of mitogen-activated protein kinase and, accordingly, partly restored PD98059-decreased secretory amyloid precursor protein-alpha secretion. In addition, huperzine A largely inhibited (-55.4%) acetylcholinesterase activity of the cell line. Our results suggest that activated M1-muscarinic acetylcholine receptor/protein kinase C pathway and mitogen-activated protein kinase signaling are involved in the process of huperzine A enhancing the secretory amyloid precursor protein-alpha secretion.