Transient Calcium and Dopamine Increase PKA Activity and DARPP-32 Phosphorylation
Figure 7
Consequences of Pairing Slower Calcium Signals with Dopamine Inputs
(A) The cumulative increase of free PKAc following eight high-amplitude, brief dopamine inputs (green line) is a bit larger than if a slow, low-amplitude calcium signal is paired with the brief dopamine inputs (red line). Also the slower, low-amplitude calcium input alone (blue line) does not give any significant increase in PKAc.
(B) Pairing slow, low-amplitude calcium inputs with dopamine inputs (red line) reduces the cumulative increase in phosphoThr34 compared with a dopamine input alone (green line). A decrease of phosphoThr34 is seen following a calcium input alone (blue line).
(C) The decrease in phosphoThr34 due to the slow, low-amplitude calcium input is due to a prolonged activation of PP2B (dashed line) compared with when a brief, high-amplitude calcium input is given (solid line).
(D) Furthermore, the calcium-activated form of PP2A (PP2Ac) is significantly less activated following a small but slower calcium input (dashed line) than if a high-amplitude calcium input is given (solid line).