Have no fear, erythropoietin is here: erythropoietin protects fear conditioning performances after functional inactivation of the amygdala

This study investigated the capacity of erythropoietin (EPO) to protect fear conditioning performances against functional inactivation of the amygdala. We infused an excitotoxic dose of glutamate in the lateral nucleus of the amygdala (LA) of adult rats in order to block the output projections to brainstem areas controlling the expression of conditioned fear responses. Subsequently, animals with excitotoxic lesions in the LA displayed altered short and long-term fear conditioned responses, but the integrity of their general emotional reactivity was preserved, as indicated by their open-field behavior. EPO infused immediately after glutamate succeeded to protect the conditioned fear performances of rats. This effect was reliably represented on both short, and long-term memory tests of conditioned fear. This and other studies have supported the potent neuroprotective activity of EPO, discriminable both morphologically, and behaviorally. (C) 2004 Elsevier B.V. All rights reserved.