Hippocampal M1 and M2 muscarinic acetylcholine receptors modulate memory reconsolidation of an inhibitory avoidance task in mice

KRAWCZYK MC; BLAKE MG; BARATTI CM; BOCCIA MM

Huerta Grande, Córdoba

Congreso; XXVIII CONGRESO ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACION EN NEUROCIENCIAS & Reunión satélite sobre Neurobiología del Comportamiento: ?NeuroetologÍa y Neurobiología de la Memoria en el cono sur? Un homenaje a Héctor Maldonado; 2013

Sociedad Argentina de Neurociencias

Previous experiments from our laboratory demonstrated that hippocampalmuscarinic acetylcholine receptors (mAChRs) play a critical role in reconsolidationof an inhibitory avoidance response in mice. However, the specific type of mAChRinvolved in this process is still unknown. To further investigate it, we trained CF-1male mice in an inhibitory avoidance (IA) task using either a mild or a highfootshock. A retention test was given 48 hours later. Immediately after it, micewere given intra-dorsal hippocampus infusions of oxotremorine (OXO, a muscarinicacetylcholine receptor agonist, 1?10 μg/hip), scopolamine (SCO, a muscarinicacetylcholine receptor antagonist, 1?10 μg/hip), pirenzepine (a specific M1muscarinic acetylcholine receptor antagonist, 1-10 μg/hip), solifenacin (a specificM3 muscarinic acetylcholine receptor antagonist, 1.5-15 μg/hip) or AF-DX116 (aspecific M2 muscarinic acetylcholine receptor antagonist, 1-7 μg/hip). Memoryretention was tested again 24 h later. Pirenzepine impaired retentionperformances regardless of footshock intensity. AF-DX116 impaired retentionperformances in mice trained with a high footshock, while enhanced retentionperformances in mice trained with a mild footshock. These effects were dose- andtime-dependent. There was no effect of solifenacin on retention performances, atleast, at the administered doses. Our results suggest that specific hippocampalmAChR M1 and M2 would be essential for the modulation of memoryreconsolidation processes of an IA task in mice.