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 Investigación en Neurociencias; 2013

Sociedad Argentina de Investigación en Neurociencias

Previous experiments from our laboratory demonstrated that hippocampal muscarinic acetylcholine receptors (mAChRs) play a critical role in reconsolidation of an inhibitory avoidance response in mice. However, the specific type of mAChR involved in this process is still unknown. To further investigate it, we trained CF-1 male mice in an inhibitory avoidance (IA) 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 oxotremorine (OXO, a muscarinic acetylcholine receptor agonist, 1?10 μg/hip), scopolamine (SCO, a muscarinic acetylcholine receptor antagonist, 1?10 μg/hip), pirenzepine (a specific M1 muscarinic acetylcholine receptor antagonist, 1-10 μg/hip), solifenacin (a specific M3 muscarinic acetylcholine receptor antagonist, 1.5-15 μg/hip) or AF-DX116 (a specific M2 muscarinic acetylcholine receptor antagonist, 1-7 μg/hip). Memory retention was tested again 24 h later. Pirenzepine impaired retention performances regardless of footshock intensity. AF-DX116 impaired retention performances in mice trained with a high footshock, while enhanced retention performances in mice trained with a mild footshock. These effects were dose- and time-dependent. There was no effect of solifenacin on retention performances, at least, at the administered doses. Our results suggest that specific hippocampal mAChR M1 and M2 would be essential for the modulation of memory reconsolidation processes of an IA task in mice.