FIGURE 6.

Occlusion of synaptic plasticity following elevation of presynaptic cAMP levels. (A) Time course of changes in normalized mEPSC frequency produced by electrical activity (50 Hz, 2 s stimulation) in TWT neurons in control conditions (black), as well as in the presence of forskolin (FSK; 10 μM; red) and IBMX (green). Points indicate mean values of mEPSC frequency (n = 5), normalized to baseline values measured prior to the stimulus train, and error bars indicate ±SEM. (B) Peak amount of augmentation of mEPSC frequency, calculated from exponential fits to the data in panel (A), in control (black), forskolin (red), and IBMX (green). (C) Amount of potentiation of mEPSC frequency in same conditions described in panel (B). Values in panels (B,C) indicate means and error bars indicate ±SEM, while asterisks indicate significant differences between control and forskolin or control and IBMX.