Hippocampal alpha7 nicotinic receptors modulate memory reconsolidation of an inhibitory avoidance task in mice

KRAWCZYK MC; BOCCIA MM; BLAKE MG; BARATTI CM

HUERTA GRANDE, CÓRDOBA

Congreso;  II RCN II Reunión Conjunta de Neurociencias – Second Joint Meeting of the Argentine Society for Neuroscience and the Argentine Workshop in Neuroscience.; 2010

SOCIEDAD ARGENTINA DE NEUROCIENCIAS

CF-1 male mice were trained in an inhibitory avoidance task using either a mild or a high footshock. A retention test was given 48 hours later. Immediately after it, mice were given intra-dorsal hippocampus infusions of either choline (Ch, an α7 nicotinic acetylcholine receptor agonist, 0.08 – 1.30 μμg/hippocampus), or methyllycaconitine(MLA, an α7 nicotinic acetylcholine receptor antagonist, 1.0  30.0 hippocampus). Memory retention was tested again 24 h later. MLA impaired retention performance regardless of footshock intensity and its effects were long lasting. Ch impaired retention performance only in those mice trained with a high footshock. On the contrary, Ch enhanced retention performance when mice were trained with a mild footshock. These effects were long lasting and dose- and time-dependent. Retention performance was not affected in drug-treated mice that were not subjected to memory reactivation, suggesting that the performance effects could not be attributable to non-specific effects of the drugs. Methyllycaconitineeffects were dose-dependently reversed by choline. Our results suggest that hippocampal a7nAChRs play a critical role in reconsolidation of an inhibitory avoidance response in mice, and may also have important implications for dynamicmemory processes.