Effects of intrahippocampal administration of the phosphatase inhibitor okadaic acid: Dual effects on memory formation

• Autor(a) principal: Vianna,Monica R.M.
• Data de Publicação: 2010
• Outros Autores: Coitinho,Adriana, Izquierdo,Luciana, Izquierdo,Ivan
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Dementia & Neuropsychologia
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1980-57642010000100023
• topic: hippocampus; PP1; PP2A; okadaic acid; short-term memory; long-term memory

Abstract Protein phosphorylation mediated by serine-threonine kinases in the hippocampus is crucial to the synaptic modifications believed to underlie memory formation. The role of phosphatases has been the focus of comparatively little study. Objectives: Here we evaluate the contribution of the serine-threonine protein phosphatases 1 and 2A (PP1, PP2A) on memory consolidation. Methods: We used immediate post-training bilateral hippocampal infusions of okadaic acid (OA, 0.01 and 10 pmol/side), a potent inhibitor of PP1 and PP2A, and measured short- [3 h] and long-term memory [24 h] (STM, LTM) of step-down inhibitory avoidance. Results: At the lower dose, OA inhibited both STM and LTM whereas at the higher dose it instead enhanced LTM. Pre-test infusion of these two doses of OA had no effect on retrieval. Conclusions: These two doses of OA are known to selectively inhibit PP1 and PP2A respectively. These findings point to the importance of these enzymes in memory formation and also suggest a deleterious influence of endogenous hippocampal PP2A on LTM formation.