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

KRAWCZYK MC; BOCCIA MM; BLAKE MG; BARATTI CM

Huerta Grane, Córdoba

Congreso; II Reunión Conjunta de Neurociencias; 2010

Sociedad Argentina de Investigación en 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 alpha7 nicotinic acetylcholine receptor agonist, 0.08 - 1.30 ug/hippocampus), or methyllicaconitine (MLA, an alpha7 nicotinic acetylcholine receptor antagonist, 1.0 - 30.0 ug/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. Methyllicaconitine effects 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 dynamic memory processes.