Short communicationInjections of the somatostatin receptor type 2 agonist L-054,264 into the amygdala block expression but not acquisition of conditioned fear in rats

- The amygdala is important for acquisition and expression of conditioned fear.
- SSTR2 is expressed in the amygdala, however, its role is poorly understood.
- We show that amygdaloid SSTR2 is important for the expression of conditioned fear.
- However, amygdaloid SSTR2 seems to play no role in fear acquisition.

The amygdala is a crucial brain site for acquisition and expression of conditioned fear. Neuropeptides such as somatostatin play a critical role in regulating the activity of the amygdala. In the present study, the specific somatostatin receptor type 2 (SSTR2) agonist L-054,264 was injected into the amygdala of rats either before fear acquisition or before the expression test on conditioned fear measured by fear-potentiated startle. L-054,264 injections strongly attenuated fear expression but did not affect fear acquisition. This suggests that amygdaloid SSTR2 plays an important role in the modulation of fear memory expression.