摘要
使用生后18～20天龄的幼年大鼠视皮层脑片标本，在LTP出现后半小时进行超微结构观察。运用白象分析仪分别对以下参数进行测量：（1）突触间隙的宽度；（2）突触后致密物（PSD）的厚度；（3）活性区的长度；（4）突触界面曲率。用双官法对突触数目进行计量，并用立体计量学方法对各种突触类型进行定量，结果显示：（1）LTP形成后半小时之内，突触反应增强，最大可达基础反应的516％；（2）PSD的厚度明显增厚；（3）活性区的面密度及突触界面曲率在备组间无明显差异；（4）穿孔性突触的数密度与对照组相比无显著差异；（5）总突触数目和棘突触数目的数密度较对照组明显增高。结果提示，PSD的增厚可能是LTI，诱导过程的形态学特征。在LTP的诱导过程中，突触数目有明显增加的趋势。
The present study examined the ultrastructure of synapses half an hour after formation of LTP in the visual conical brain slices of young rats aged 18-20 days. The following parameters was examined by using the image analyzer: (1)the width of the synaptic cleft I (2)the thickness of the postsynaptic densities (PSD) 3 (3)the length of the active zones land (4)the curvature of the synaptic interface. Double-blind scoring procedures were used to quantify the number of synapse of different types. These counts were converted to the number of synapses per unit volume (Nv) using stereological morphometric techniques. Our results suggest that: (1)field potentials recorded in layer n / m of visual cortex are potentiated gradually in half an hour after tetanus,with the largest extent of potentiation reaching 516% relative to baseline; (2)the thickness of thepostsynaptic densities(PSD) increased significantly I (3)the Sv of active zones and the curvature of the synaptic interface do not show significant change4 (4)the Nc of the perforated synapses do not show significant change I (5)the Nv of total synapses and spine synapses,especially negatively curved spine synapses,increased significantly. These data suggest that the thickness of PSD underlies the induction of LTP. There is a tendency that the number of synapse increases with the induction of LTP.
基金
广东省自然科学基金!960775
广东省卫生厅五个一科教兴医重点项目
关键词
视皮层
突触
长时程增强
LTP visual cortical brain slice synaptic cleft postsynaptic densities(PSD) the curvature of the synaptic interface spine synapse perforated synapse
