Previous stress attenuates the suceptibility to midazolam’s disruptive effect on fear memory reconsolidation: influence of D-cycloserine

SILVIA G. BUSTOS, MARCELO GIACHERO, HÉCTOR MALDONADO Y VÍCTOR A. MOLINA

Rosario, Argentina

Congreso; XLI Reunión Anual de Sociedad Argentina de Farmacología Experimental (SAFE); 2009

Sociedad Argentina de Farmacología Experimental (SAFE)

The retrieval of a consolidated memory results into a labile phase, vulnerable to interference by benzodiazepines. The aims of the present study was to assess MDZ vulnerability after reactivation of recent and remote contextual fear memories in animals that had experienced a stressful situation prior to acquisition. Male Wistar rats were subjected on day 1 to a stressful session and on day 2 submitted to a contextual fear conditioning paradigm and 1, 7 or 21 days after training re-exposed to the training context (A) for 3 or 5 min. Immediately after retrieval rats were administered (i.p.) either with SAL, MDZ 1.5 mg/kg, or MDZ 3 mg/kg. One day later, rats were tested in A. The results showed that MDZ does not affect reconsolidation of a 7-day and 21-day fear memory in stressed animals regardless of the duration of the re-exposure period and the MDZ doses used. In addition, we tested the influence of pre-reactivation D-cycloserine (DCS) on MDZ´s effect on fear memory reconsolidation in stressed animals. Our evidence showed that: a) Previous stress prevents MDZ’s disruptive effect on memory reconsolidation of a fear memory and b). DCS prior to reactivation promotes retrieval-induced lability in resistant memory traces.