Figure 13.

Calculated vesicular steady-state DA concentrations $D{A}_{ves}$ as a function of cytosolic DA levels and DOPA controller accuracy $k_8$ (Equation (15)). At high controller accuracy (low $k_8$, line no. 5), $D{A}_{ves}$ levels are less affected when DA concentrations decrease. At low controller accuracy (high $k_8$, line no. 1), $D{A}_{ves}$ levels decrease rapidly with increased DOPA perturbations and with decreasing DA concentrations. $k_8$ values used: 1, 29 $\mathsf{\mu }$M; 2, 2.9 $\mathsf{\mu }$M; 3, 0.29 $\mathsf{\mu }$M; 4, 0.029 $\mathsf{\mu }$M; and 5, 0.0029 $\mathsf{\mu }$M.