Computer simulations aid the discovery of disorders of signal transmission in the nervous system
The March issue of The Journal of Physical Chemistry B published an article co-authored by Dr. Magdalena Krupa, assistant professor in the Computational Biology Group of the Institute of Computer Science PAS, entitled: "Unusual Robustness of Neurotransmitter Vesicle Membranes against Serotonin-Induced Perturbations". The figure contained in the article was chosen for the cover of this issue of the magazine.
Our body stores neurotransmitters, like serotonin, in synaptic vesicles. However, scientists have been puzzled about how the lipid bilayer membrane in these vesicles remains stable despite the high concentration of serotonin. To understand this phenomenon, researchers studied a mixture of phospholipids in ratios similar to those found in natural vesicles. They found that this mixture was barely affected by serotonin, even at physiological concentrations. This suggests that nature has evolved to use a specific mixture of lipids that have emergent mechanical properties to regulate the effects of serotonin.
To understand this on a molecular level, researchers performed molecular dynamics (MD) simulations to observe the mechanical changes caused by serotonin on the lipid bilayer membranes of synaptic vesicles. Additionally, they used a technique called steered molecular dynamics (SMD) simulation to mimic the force exerted by atomic force microscopy (AFM) during indentation experiments. Through these simulations, they were able to gain insights into the opposite mechanical perturbations of phosphatidylcholine (POPC) and phosphatidylserine (POPS) membranes caused by serotonin.
The interaction between neurotransmitters and the lipid bilayers of neurons is a crucial aspect of signal transmission in the nervous system. Our study demonstrates that proper lipid composition is necessary to prevent the negative impact of certain neurotransmitters, such as serotonin and dopamine, on neurons and imperfections in lipid composition can lead to disturbances in neurotransmitter signaling, which may contribute to various health problems.