INVOLVEMENT OF NMDA RECEPTORS IN THE ACQUISITION OF CONTEXTUAL FEAR MEMORY IN PREWEANLING AND WEANLING RATS, TRAINED IN THE CONTEXT PREEXPOSURE FACILITATION EFFECT PARADIGM

PISANO, M.V.; PAGLINI, M.G.; ABATE, P.; ARIAS, C.

New Orleans

Congreso; International society for Developmental Psychobiology; 2012

International society for Developmental Psychobiology

It is thought that the capability to acquire contextual fear learning emerge around weaning in rats, and that this capability is NMDA-type glutamate receptors(NMDAr) dependent.Arecent study using the Context Preexposure Facilitation Effect (CPFE) procedure demonstrated evidences of contextual fear conditioning in preweanling rats (postnatal day 17). Additionally, it was observed that preweanling and weaning rats trained with an immediate-shock procedure showed evidences of fear conditioning. In this study, the observation of contextual fear conditioning at this age was facilitated by the temporal analysis of multiple behaviors. The aim of the present study was (1) to study the involvement of the NMDAr in the acquisition of contextual fear in weaning and preweanling rats (experiments 1a and 1b), and (2) to evaluate the involvement of these receptors in fear conditioning induced by an immediate-shock procedure (Experiment 2). Results obtained in these experiments showed that contextual fear memory is NMDAr-dependent at both ages. The behavioral pattern expressed by preexposed subjects treated with MK-801 (an NMDAr antagonist) during the preexposure phase was identical to the one observed in non-preexposed rats. Finally, fear memory induced by the immediate-shock treatment was not affected by the administration of MK-801. These results allow us to conclude that NMDAr modulate the acquisition of contextual fear conditioning in preweanling and weanling rats.