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 MARÍA VICTORIA; PAULA ABATE; PAGLINI GABRIELA; ARIAS CARLOS

New Orleans, LA

Congreso; 44th Annual Meeting of the International Society for Developmental Psychobiology (ISDP); 2012

ISDP

INVOLVEMENT OF NMDA RECEPTORS IN THE ACQUISITION OF CONTEXTUAL FEAR MEMORY IN PREWEANLING AND WEANLING RATS, TRAINED IN THE CONTEXT PREEXPOSURE FACILITATION EFFECT PARADIGM. M. V. Pisano, G. Paglini, P. Abate, C. Arias. 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. A recent 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 weanling 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 weanling 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. We conclude that NMDAr modulate the acquisition of contextual fear conditioning in preweanling and weanling rats.