Fig. 4.

Increase in the enzymatic activity and protein expression of calcineurin after extinction training. A, Rats were assigned into three groups (naive, unpaired, and paired; 12 rats in each group), and each group was trained according to its own protocol. After training, six rats in each group were killed, and the release of Pi from LA and BLA was measured. Next, the remaining six rats in each group were subjected to extinction training, and calcineurin activity was measured after training. After extinction training, the release of Pi was enhanced only in the paired rats. ***p < 0.001 versus naive or unpaired groups.B, Time course of calcineurin expression induced by light-alone trials in cytosolic fraction. Shown are representative blots and mean ± SE of calcineurin immunoreactivities from rats decapitated at various time points (n = 6 rats in each time point) after extinction training (α-actin was used as internal control). **p < 0.01 and ***p < 0.001 versus paired.