Calcitonin gene-related peptide released within the amygdala is involved in pavlovian auditory fear conditioning

The effects of CGRP and the CGRP receptor antagonist hCGRP(8-37) injected i nto the amygdala on both the acquisition and expression of fear behavior to a discrete auditory conditional stimulus (CS) and the training context wer e assessed. In Experiment 1, pretraining injections of CGRP but not hCGRP(8 -37) produced fear-like behavior before any aversive stimuli were presented . While both compounds attenuated freezing to the contextual CS on the test day, neither affected learning about the auditory CS. In Experiment 2, pre testing injections of hCGRP(8-37) (0.63 mM) selectively attenuated freezing to the auditory CS but left freezing to the contextual CS intact. These da ta suggest that CGRP in the amygdala may selectively contribute to the expr ession of learning about auditory stimuli during fear conditioning. (C) 200 1 Academic Press.