Orexin signaling during social defeat stress influences subsequent social interaction behaviour and recognition memory.

Orexin signaling during social defeat stress influences subsequent social interaction behaviour and recognition memory.
Behav Brain Res. 2018 Jun 11;:
Authors: Eacret D, Grafe LA, Dobkin J, Gotter AL, Rengerb JJ, Winrow CJ, Bhatnagar S
Abstract
Orexins are neuropeptides synthesized in the lateral hypothalamus that influence arousal, feeding, reward pathways, and the response to stress. However, the role of orexins in repeated stress is not fully characterized. Here, we examined how orexins and their receptors contribute to the coping response during repeated social defeat and subsequent anxiety-like and memory-related behaviors. Specifically, we used Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) to stimulate orexins prior to each of five consecutive days of social defeat stress in adult male rats. Additionally, we determined the role of the orexin 2 receptor in these behaviors by using a selective orexin 2 receptor antagonist (MK-1064) administered prior to each social defeat. Following the 5 day social defeat conditioning period, rats were evaluated in social interaction and novel object recognition paradigms to assess anxiety-like behavior and recognition memory, respectively. Activation of orexin neurons by DREADDs prior to each social defeat decreased the average latency to become defeated across 5 days, indicative of a passive coping strategy that we have previously linked to a stress vulnerable phenotype....

Source: Behavioural Brain Research - June 11, 2018 Category: Neurology Authors: Eacret D, Grafe LA, Dobkin J, Gotter AL, Rengerb JJ, Winrow CJ, Bhatnagar S Tags: Behav Brain Res Source Type: research