Fig. 4.

Incorporation of Ca²⁺-mediated inhibition of type 5/6 AC into the model. a Graphical notation used by CellDesigner to depict β-AR signaling molecules: cardiac AC subtypes (AC5/6), non-cardiac AC subtypes (AC4/7), cAMP, Ca²⁺, and PKA. A negative feedback loop was not observed. b Computational oscillation loop of β-AR signaling molecules: cAMP, Ca²⁺, AC5/6, PDE, and PKA did not form a continuous negative feedback loop, and then faded. However, essentially no oscillation occurred. The intracellular concentration of cAMP at baseline (0 min) was taken as 1 (arbitrary units)