海马CA3区突触结构在记忆中的变化

Alterations of the synaptic structure in hippocampal CA, during the retention of memory

目的探讨突触结构的可塑性变化与记忆保持的关系。方法昆明品系1月龄小白鼠60只,进行一次性被动回避反应学习,在记忆形成前与后的不同时期取脑海马CA3区,用电子透镜检测其突触结构的变化。结果在学习后24h、记忆保持良好(步人潜伏期>300s)时,穿孔突触由学习前占突触总数的6. 3％增加到40.8％(P<0.01,其中轴棘穿孔突触为31.2％,轴树穿孔突触为9.6％);突触活性区长度(>320nm)由学习前占6.2％增至30.8％(P<0.05)。记忆减退(学习后6d)、消退(学习后12d)变化均逐渐减至接近学习前的水平。

Objective To investigate the relationship between synaptic structure plasticity and memory retention. Methods One-trial passive avoidance response was used in young mice aged 30 days. Hippocampal CA3 area was taken before or after the memory formation at different phase, and the changes of synaptic structure were examined under the electron microscope. Results 24 hours after animal learning with the good memory retention (Step Through Latency, STL >300sec) , the number of perforated synapses (perforated axospinous synapses 31. 2% , axodendritic synapses 9. 6% ) significantly increased to 40. 8% compared with the number before learning (6. 3% , P<0. 01). The length of synaptic active zone also increased 30. 8% compared with the number before learning (6. 2% , P<0. 05). These changes gradually degreased to the level of before learning with the memory decay (6 days after learning) or extinction (12 days after learning) . Conclusions The synaptic structure plasticity of hippocampal CA3 was found in the retention of one-trial passive avoidance response.