Variation of the relative size of the alkaline vesicle population can be predicted by modeling.

<p>For simulation, the time constants for endocytosis and for reacidification were modeled to be variable to the stimulus condition. (A) Relative size of the alkaline vesicle population depending on the action potential number according to the “ideal” model. Endocytosis time constants were derived by deconvolution. The relative alkaline vesicle population size decreased with rising number of action potentials. The stimulus 50ap20Hz was omitted, as it was not possible to calculate an endocytosis time constant by deconvolution due to low signal-to-noise ratio. (B) Relative size of the alkaline vesicle population depending on the action potential frequency according to the “ideal” model. Endocytosis time constants were derived by deconvolution. The relative alkaline vesicle population size increased with rising number of action potential frequency. (C) Relative size of the alkaline vesicle population depending on the action potential number according to the “ideal” model. Endocytosis time constants were derived by monoexponential curve fitting from the decaying surface pool time course. The calculated relative alkaline vesicle population size reflects the experimentally defined alkaline vesicle population dynamics (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102723#pone-0102723-g003" target="_blank">Figure 3</a>) except for stimulation with 50ap20Hz. (D) Relative size of the alkaline vesicle population depending on the action potential frequency according to the “ideal” model. Endocytosis time constants were derived by monoexponential curve fitting from the decaying surface pool time course. The calculated relative alkaline vesicle population size reflects the experimentally defined alkaline vesicle population dynamics (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102723#pone-0102723-g004" target="_blank">Figure 4</a>) except for stimulation with 200ap80Hz.