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Behavioural Brain Research


The opiate-receptor antagonist naloxone was administered to rats after passive-avoidance training either alone or in combination with forced-swim stress. A retention test revealed that while naloxone enhanced retention when administered alone, it impaired retention when administered in combination with forced-swim stress. The findings provide evidence for a “protective” endogenous opioid-based system that, when not blocked pharmacologically, limits enhancement or impairment of retention under conditions of mild and intense stress, respectively.


This work is a preprint that has been provided to PubMed Central courtesy of Elsevier.

This paper was originally presented at the 2009 Society for Neuroscience meeting.

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