Neural mechanism underlying regulation of emotional behavior via δ-opioid receptors

Abstract

After the retrieval, consolidated fear memory undergoes reconsolidation to maintain the memory when it still necessary to remember, otherwise extinction to reduce fear response. In pathophysiology of fear-related disorders, such as PTSD and phobia, heightened/persistent fear memory has been well established. Therefore, the development of a method by which facilitates extinction or suppresses reconsolidation seems useful for the treatment of the aforementioned diseases. In this context, we show here that the activation of δ-opioid receptor (DOP) facilitates extinction and disrupts reconsolidation of contextual fear memory in mice. In addition, DOPs in the amygdala and infralimbic subregion of the medial prefrontal cortex (IL) are participate in facilitation of fear extinction. Along with the behavioral changes, excitatory synaptic transmission in the IL, a brain region positively stimulates the extinction, is enhanced by DOP activation. These results suggest that DOPs can be a target molecule for a desirable therapeutic agent for fear-related disorders.