Effect of alpha-MSH on the reconsolidation of a contextual fear memory; melanocortinergic receptors and mechanisms involved.

Mar del Plata

Congreso; XXX Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias (SAN); 2015

SAN Sociedad Argentina de Investigación en Neurociencias

Melanocortins are important modulators of the immune response, and they have diverse and important effects in the central nervous system. Between them, alpha-MSH can modulate the consolidation and reconsolidation of a contextual fear memory during inflammatory processes. However, the effect of alpha-MSH on these processes, in physiological conditions, is not clearly established yet. The objective of the present study was to determine the effect of alpha-MSH on the reconsolidation of a contextual fear memory, the melanocortinergic receptors involved and possible molecular mechanisms. Our results showed that the intrahippocampal administration of alpha-MSH after memory reactivation can increase the percent of freezing during the test. This effect would be specific to the reconsolidation process because it is only observed when the memory was reactivated. The effect of alpha-MSH is mediated by the activation of the MC4R. Our results also demonstrated that the treatment with alpha-MSH didn?t produce changes in the expression of zif-268, a transcription factor specifically involved in memory reconsolidation. Our results demonstrated that alpha-MSH has an effect on memory reconsolidation through the activation of MC4R.