Investigation of an increased DA amount in the nerve cell. The four diagrams show the flux changes while the tyrosine input flux is increased from 0 to 100 μM·h−1. Sub-diagram A and B depict the results of the FBA with target function maxDeg. Sub-diagram C and D display the results of the FBA with target function minApo. The tyrosine input reaction acts as precursor flux for the DA synthesis and metabolism in the nerve cell model. If this flux is increased, the DA content in the cell rises. Sub-diagram A and C summarize all fluxes that produce ROS and/or cause damage in the cell. In contrast, sub-diagram B and D contain all fluxes that are considered responses or consequences of fluxes shown in sub-diagram A to retain the normal cellular function.