The role of the IKK / NF-kappa B signaling pathways in the extinction of auditory fear condition

Abstract

Objective To identify the role of the IKK / NF-kappa B signaling pathways in the acquisition and consolidation of extinction memory in conditioning fear. Methods Adult SD rats were treated with nuclei buried surgery. After a week recovery from nuclei buried surgery, adult SD rats accepted auditory fear conditioning training. Before the extinction training, bilateral intra-BLA infusion of sulfasalazine(SSZ), an inhibitor of IKK/NF-κ B, and Vehicle were done. The freezing time were tested on the 24h and 1w after the extinction. Results After training, all the rats showed higher percentage of freezing time than the baseline(Vehicle: pre-CS 21.16%, post-CS 71.23%, P 0.05)between Vehicle and SSZ at the end of extinction training. However, SSZ groups showed significantly higher percentage of freezing time than the control group on the 24h(Vehicle 41.03%, SSZ 60.51%, P<0.01) and the same was found on 1 week test(Vehicle 34.17%, SSZ 57.21%, P<0.01). The rats injection with SSZ showed significant fear response for the auditory fear condition. Conclusion All above results suggest that interference of IKK/NF-κ B signaling pathway impaire the consolidation but have no effect on the acquisition of fear extinction memory in conditioning fear.The available date could provide us some clinical guidance in the treatment of post-traumatic stress disorder and panic disorder. Key words: Auditory fear condition; Extinction; IKK/NF-kappa B signaling pathways; Sulfasalazine