Matus A, Brinkhaus H, Wagner U
Friedrich Miescher Institute, Basel, Switzerland.
Hippocampus. 2000;10(5):555-60. doi: 10.1002/1098-1063(2000)10:5<555::AID-HIPO5>3.0.CO;2-Z.
Dendritic spines form the postsynaptic element at most excitatory synapses in the brain. The spine cytoskeleton consists of actin filaments which, in time-lapse recordings of living neurons expressing actin labeled with green fluorescent protein, can be seen to undergo rapid, dynamic changes. Because actin dynamics are associated with changes in cell shape, these cytoskeletal rearrangements may form a molecular basis for the morphological plasticity at brain synapses. The rapidity of these dynamic events in dendritic spines raises new questions. First, do the changes in actin cytoskeleton that are visible by light microscopy really correspond to changes in spine morphology, or do they represent changes in the relationship between actin and its many binding partners at postsynaptic sites? Second, how are these changes regulated by synaptic transmission? Third, to what extent do these changes occur in organized brain tissue? Answers to these questions are now beginning to emerge.
树突棘构成了大脑中大多数兴奋性突触的突触后元件。棘突细胞骨架由肌动蛋白丝组成，在表达用绿色荧光蛋白标记的肌动蛋白的活神经元的延时记录中，可以看到这些肌动蛋白丝会经历快速、动态的变化。由于肌动蛋白动力学与细胞形状的变化相关，这些细胞骨架重排可能为脑突触的形态可塑性形成分子基础。树突棘中这些动态事件的快速性引发了新的问题。首先，通过光学显微镜可见的肌动蛋白细胞骨架的变化真的与棘突形态的变化相对应吗，还是它们代表了肌动蛋白与其在突触后位点的许多结合伙伴之间关系的变化？其次，这些变化是如何由突触传递调节的？第三，这些变化在有组织的脑组织中发生的程度如何？现在这些问题的答案开始浮现出来。
