Molecular Dynamics Simulation of Dopamine Diffusion within and Permeation through POPC Phospholipid Bilayer Membrane

Abstract

Dopamine, which is an important neural transmitter in brain tissue, needs to move freely within and through cell membranes to fulfill its function. The molecular dynamics of dopamine diffusion within and permeation through, cell membranes are involved in smoothing dopamine molecular protective channels, associated with schizophrenia and Parkinson′s disease. In the present work, using a 1palmitoyl2oleoylglycero3phosphatedylcholine (POPC) phospholipid bilayer membrane to model the cell membrane, we obtained the freeenergy changes (ΔG) for dopamine diffusion within and permeation through the cell membrane, using molecular dynamics simulations, and probed the molecular dynamics of dopamine diffusion and permeation. The obtained values of ΔG for dopamine diffusion within the cell membrane were 10-54 kJ∙mol-1 at 310 K, which implies that dopamine diffuses easily horizontally and vertically within the cell membrane to protect smoothing of the protective channel. However, it is not easy for dopamine to permeate through the cell membrane, because ΔG for this process was 117-125 kJ∙mol-1 (310 K). Superfluous dopamine passes through the dopamine molecular protective channel and enters the middle region of the phospholipid bilayer membrane, and then diffuses easily along the horizontal and vertical orientations within the cell membrane, even permeating through the cell membrane, preventing 183 Acta Phys. -Chim. Sin. 2014 Vol.30 schizophrenia. It is therefore important for the normal function of a biological cell membrane to protect smoothing of dopamine molecular protective channels, preventing schizophrenia. These results are in agreement with other experimental observations.