CREB Phosphorylation Coincides with Transient Synapse Formation in the Rat Hippocampal Dentate Gyrus Following Avoidance Learning

[摘要] Spine density change in the hippocampaldentate gyrus accompanies memory consolidationand coincides with the increased expression ofribosome-rich, hyperchromatic granule cells.Although this suggests increased protein synthesisto be required for synaptic growth in the 5 to 7 hpost-training period, little temporal mapping ofthe associated molecular mechanisms has beendone. Here, we demonstrate a similar frequencyof hyperchromatic cells in naïve animals and inthose sacrificed 6 h post-training, suggesting atransient repression of protein synthesis in theearly post-training period. Immunoblot analysisof CREB phosphorylation in the dentate gyrussupported this view, with downregulation frombasal levels observed at 2 to 3 h and at 12 h posttraining.Protein synthesis reactivation appears tobe specific forde novospine production as nochange in spine frequency accompanies theimmediate post-training period of depressedprotein synthesis. These findings support the viewthat CREB-mediated gene transcription is arequirement for long-term memory consolidationand may be directly implicated in the process ofsynaptic growth.

[学科分类] 精神健康和精神病学