TY - JOUR AU - Kawahara Shigenori PY - 2016 TI - Erasing fear memories — key receptor and essential timeframe discovered JF - Acta Pharmacologica Sinica; Vol 32, No 1 (January 2011): Acta Pharmacologica Sinica Y2 - 2016 KW - N2 - It is clinically important to suppress or inhibit traumatic memories, which are formed after fearful experiences. In animal models, fear memory is formed by repetitive presentation of a tone paired with an electrical foot-shock 1 . It is well known that an extinction protocol, in which the tone is repeatedly presented without the foot-shock, gradually decreases the pre-acquired fear response to the tone. However, this fear extinction protocol is not sufficient to erase the fear memory; fear responses may recover spontaneously or relapse under some conditions. If the fear memory is retrieved or reactivated by a single presentation of the tone without the shock 1 h before the extinction session, the fear responses are permanently removed by this retrieval–extinction protocol 2 . This suggests that a critical brain state is caused by the retrieval procedure, in which the fear memory becomes labile and can be destroyed by the subsequent extinction procedure. Clem and Huganir 3 have found a critical receptor for the permanent erasure of fear memories by this retrieval–extinction protocol. They focused on the Ca 2+ -permeable type of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor (Ca 2+ -permeable-AMPAR) located in the lateral amygdala, an essential region of the brain for learning. They suggested that removal of Ca 2+ -permeable-AMPARs, the content of which in the synapses is elevated for a few days after fear conditioning, is responsible for the permanent erasure of the fear memory by that protocol. UR - http://www.chinaphar.com/article/view/4853