Disruption of fear memory reconsolidation in ethanol withdrawn rats: influence of d-cycloserine.

Valparaiso

Workshop; . II International Workshop, Motivated behavior, stress and addiction from molecules to behavior.; 2012

We have recently reported that withdrawal from chronic ethanol (ETOH) administration facilitated the formation of contextual fear memory, when anxiety induced by abrupt ethanol discontinuation was no longer evident.Furthermore, a resistance to the disruptive effect of the â-adrenergic receptor antagonist propranolol (PROP) following memory reactivation was observed in ETOH withdrawn rats. This effect was obtained using a strong fear conditioning procedure that induced a similar fear response in control and ETOH groups. Here we examine whether the activation of NMDA receptors before memory reactivation would be effective in inducing instability after retrieval and in turn, promoting vulnerability to the disruptive effect of PROP on fear memory in withdrawn rats. Male Wistar rats made dependent via an ETOH containing liquid diet (6% v/v) for 14 days. Contextual fear conditioning was performed 3 days after withdrawal. The next day, rats received an injection of d-cycloserine (DCS, a NMDA partial agonist; 5 mg/kg i.p, a dose which was ineffective in control rats) or saline (SAL) 30 min before a 5 min reactivation session. Immediately after, animals received PROP (10 mg/kg i.p) or SAL. The freezing response was evaluated 24 h after. An affective attenuation of the fear response was observed in ETOH withdrawn rats treated with DCS/PROP. The freezing levels of DCS/PROP ETOH treated groups were equivalent to those exhibited by SAL/PROP or DCS/PROP control animals. These effects lasted up to one week. Our findings indicate that this protocol is an effective treatment for disrupting fear memory reconsolidation in ETOH dependent rats.