The role of glutamate in neuronal ion homeostasis: A case study of spreading depolarization
Fig 4
SD simulations with reduced uptake rates.
Panel (a) and (b) show SD for K+ perfusion with uptake rates reduced to 20% and 18% of the normal value from Table C in S1 Text. The plots show that repolarization and recovery are delayed and the delay is longer for more reduced glutamate uptake. The repolarization time with normal uptake is indicated by the vertical dashed line. Before repolarization, the system shows low amplitude membrane potential oscillations. Panel (c) shows the evolution of the glutamate concentration in the synaptic clefts during the two simulations. Delayed recovery correlates with slower glutamate clearance. Before repolarization, there are glutamate spikes because of the membrane potential oscillations. Panel (d) gives an overview of SD durations for reduced uptake rates. In our model, the effect becomes noticeable only for rates of 35% and less. Extreme durations can be up to 500 sec, and recovery fails for uptake rates of less than 16%.