Fischer M, Kaech S, Knutti D, Matus A
Friedrich Miescher Institute, Basel, Switzerland.
Neuron. 1998 May;20(5):847-54. doi: 10.1016/s0896-6273(00)80467-5.
Dendritic spines have been proposed as primary sites of synaptic plasticity in the brain. Consistent with this hypothesis, spines contain high concentrations of actin, suggesting that they might be motile. To investigate this possibility, we made video recordings from hippocampal neurons expressing actin tagged with green fluorescent protein (GFP-actin). This reagent incorporates into actin-containing structures and allows the visualization of actin dynamics in living neurons. In mature neurons, recordings of GFP fluorescence revealed large actin-dependent changes in dendritic spine shape, similar to those inferred from previous studies using fixed tissues. Visible changes occurred within seconds, suggesting that anatomical plasticity at synapses can be extremely rapid. As well as providing a molecular basis for structural plasticity, the presence of motile actin in dendritic spines implicates the postsynaptic element as a primary site of this phenomenon.
树突棘被认为是大脑中突触可塑性的主要位点。与这一假说相符的是，树突棘含有高浓度的肌动蛋白，这表明它们可能具有运动性。为了探究这种可能性，我们对表达绿色荧光蛋白标记的肌动蛋白（GFP-肌动蛋白）的海马神经元进行了视频记录。这种试剂会整合到含肌动蛋白的结构中，并能使我们观察活神经元中肌动蛋白的动态变化。在成熟神经元中，对GFP荧光的记录显示，树突棘形状发生了大量依赖于肌动蛋白的变化，这与之前使用固定组织的研究所推断的结果相似。可见的变化在数秒内就会出现，这表明突触处的解剖学可塑性可能极其迅速。除了为结构可塑性提供分子基础外，树突棘中可运动肌动蛋白的存在表明突触后元件是这一现象的主要位点。
