Corticotropin releasing factor in the median raphe nucleus is involved in the retrieval of fear memory in rats

In the present study, we examined the role of corticotropin releasing factor (CRF) in the median raphe nucleus (MRN) on fear-related behaviors in rats. We employed the contextual fear conditioning test and the elevated plus maze test as memory-dependent and -independent tasks, respectively. Human/rat CRF (10 ng) in 0.5 μl saline was injected into the MRN. Administration of CRF significantly increased memory dependent, but not independent, fear expression. These results suggest that CRF release in the MRN is involved in the retrieval of fear memory.