Figure 8

Influence of the amount of Pde1 and Pde2 on the establishment of cAMP oscillatory regimes. The figure shows the oscillations amplitude of cAMP dynamics resulting from a PSA-2D on the values of the initial amounts of Pde1 and Pde2, varied in the intervals [0, 2, 800] and [0, 13, 000], respectively (being Pde1 = 1,400 and Pde2 = 6,500 molecules the reference values—see Table 2). In the plot, the values on the x- and y-axis were normalized in the interval [0, 1]; a total of 200 initial conditions were sampled from the specified bidimensional parameters space. This analysis shows that the deletion of the high-affinity phosphodiesterase Pde2 fosters the establishment of oscillations of cAMP, whose amplitude increases with the increase of Pde1 amount (from point A to point C); on the contrary, the deletion of the low-affinity cAMP phosphodiesterase Pde1 has the effect of diminishing or even abolishing the oscillations irrespective of the amount of Pde2 (from point A to B). The overexpression of both phosphodiesterases (point D) does not allow the establishment of oscillatory regimes.