Hippocampal ERK2 differential activation after memory reconsolidation processes are modulated by alpha7-nicotinic acetylcholine receptors

KRAWCZYK M; NAVARRO N; BARATTI CM; BLAKE MG; ROMANO A; FELD M; BOCCIA MM

Mar del Plata, Buenos Aires

Congreso; XXX Reunión anual de la Sociedad Argentina de Investigaciones en Neurociencias; 2015

Sociedad Argentina de Investigaciones en Neurociencias

We have previously reported not only that hippocampal alpha7-nicotinic acetylcholine receptors (nAChRs) play a critical role in reconsolidation processes but also that there is a differential activation of extracellular signal-regulated kinases (ERK1/2) after a reconsolidation process in mice trained in an inhibitory avoidance task. Next, we determined whether nAChRs activation/inactivation is able to modulate ERK1/2; responsible of, at least in part, the behavioral changes observed in subsequent tests after memory reconsolidation.With these in mind, CF-1 male mice were trained in an inhibitory avoidance task using either a mild (0.8 mA, 1s) or a strong (1.2 mA, 1 s) footshock. A reactivation test (T1) was given 48 hours later. Immediately after it, mice were given intra-dorsal hippocampal infusions of choline, an alpha7-nAchRs agonist (Ch, 0.80 g/hippocampus), methyllycaconitine, an alpha7-nAchRs antagonist (MLA, 10.00 ug/hippocampus) or vehicle. Fifteen or forty-five minutes afterwards, the hippocampi were dissected and ERK1/2 activation was determined in nuclear and cytosolic fractions. Ch or MLA, given immediately after memory reactivation, modified ERK2 pattern of activation depending on both, training conditions and time elapsed after memory reactivation.Altogether, our results point for the first time to an alpha7-nAChRs-related ERK2 pattern of activation induced during memory reconsolidation modulation.