The interaction of neurotransmitters with lipid bilayer membranes
Recent studies have shown that serotonin, a major neurotransmitter in the mammalian brain, can bind directly to lipid membranes with high affinity. It has been suggested that this can contribute to signal transduction in a receptor independent fashion. We also hypothesize that this may have a role in membrane-amyloid interactions. Here we probe these possibilities by studying the effect of serotonin on an artificial ternary lipid bilayer and also on the membranes of living cells, using AFM and confocal imaging, and force spectroscopy. Our results show that direct interaction of serotonin with lipid bilayer membranes can alter their properties, which can have a significant effect on the ability of a cell to bind disease-associated proteins, and on the activity of generic membrane proteins. We infer that serotonin can effect cellular properties through a receptor-independent membrane mediated pathway.