Participation of hippocampal cholinergic system in memory persistence for inhibitory avoidance in rats

Gustavo M. Parfitt, Renan C. Campos, Ândrea K. Barbosa, André P. Koth, Daniela M. Barros
Neurobiology of Learning and Memory. 2012-02-01; 97(2): 183-188
DOI: 10.1016/j.nlm.2011.12.001

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Parfitt GM(1), Campos RC, Barbosa AK, Koth AP, Barros DM.

Author information:
(1)Programa de Pós-graduação em Ciências Fisiológicas, Fisiologia Animal
Comparada, Laboratório de Neurociências (FURG), Brazil.

Memory persistence needs a new event of consolidation 12h after the acquisition.
We investigated the role of the cholinergic activity on the persistence of
memory. For this purpose, we performed the treatments 9 or 12h after acquisition
and the memory tested 2 or 7 days after inhibitory avoidance (IA) training. Here
we report that activity of medial septum, by transitorily inactivating this
structure with lidocaine 12h after IA training, is essential for memory
persistence at the 7th day, but not for the formation at the 2nd day. We also
report that muscarinic and nicotinic cholinergic receptors of CA1 area are
engaged on memory persistence. Since scopolamine (mAChRs antagonist) and
mecamylamine (nAChRs blocker) infusions, 12h post-training, demonstrated
impairment on long term memory (LTM), persistence on the 7th day but no effect
on LTM formation was found on the 2nd day in the IA test. The same effects were
found with pirenzepine, an M1 antagonist. No effects on the formation and
persistence of memory on the 2nd and 7th days were demonstrated after DHβE
infusions (nAChRs subtype antagonist α4β2, α3β2). These findings suggest that
mAChR and nAChR at the CA1 area, and also MS activation, are required for the
persistence of memory.