Solutions to the inequality given in Equation (6) for two different values of the model parameter C . A) C0 = 1.044; B) C0 = .044. The overlapping shaded regions of these figures illustrate the parameter ranges for D and D0 where the model predicts the possibility of cAMP oscillation. The black region is Γ = 33.6, the Γ value for Ma et al. wt; the blue region is Γ = 3.36; and the red region is Γ = .336. In both cases, M = .01.