Institute of Anatomy I: Cellular Neurobiology, University Medical Center, Martinistr. 52, 20246 Hamburg, Germany.
Psychoneuroendocrinology. 2009 Dec;34 Suppl 1:S123-9. doi: 10.1016/j.psyneuen.2009.08.013.
Estrogen-induced synaptic plasticity was frequently shown by an increase of spines at apical dendrites of CA1 pyramidal neurons after systemic application of estradiol to ovariectomized rats. Surprisingly, exogenous application of estradiol to hippocampal cultures had no effect on spines and on spine synapses, although quantitative immunohistochemistry revealed an upregulation of spinophilin and of synaptophysin, in these cultures. The role of synaptophysin as a presynaptic marker and of spinophilin as a postsynaptic marker, appears questionable from these discrepancies. In contrast, synaptopodin, a marker protein of "mature" mushroom-shaped spines, was downregulated after treatment of hippocampal cultures with estradiol. Synaptopodin is strongly associated to the spine apparatus, a spine-specific cell organelle, which is present in 80% of all mushroom-shaped spines. Consistently, we found a reduction in the number of spines, containing a spine apparatus in response to estradiol, suggesting that the presence of a spine apparatus in many but not all spines is very likely a result of their dynamic character. In summary, synaptic proteins appear to be regulated by estradiol, independent of its function on spine and spine synapse formation.
雌激素诱导的突触可塑性通常表现为，给去卵巢大鼠全身施用雌二醇后，CA1 锥体神经元的树突顶部长出更多的棘突。令人惊讶的是，尽管定量免疫组织化学显示这些培养物中的突触小泡相关蛋白和突触素的表达上调，但外源性应用雌二醇对棘突和棘突触没有影响。从这些差异来看，突触小泡相关蛋白作为突触前标记物和突触磷蛋白作为突触后标记物的作用似乎值得怀疑。相比之下，蘑菇形棘突的“成熟”标志物突触足蛋白在用雌二醇处理海马培养物后下调。突触足蛋白与棘突小体强烈相关，棘突小体是一种棘突特异性细胞细胞器，存在于 80%的蘑菇形棘突中。一致地，我们发现，响应雌二醇，含有棘突小体的棘突数量减少，这表明棘突小体的存在（在许多棘突中，但不是所有棘突中）很可能是其动态特性的结果。总之，突触蛋白似乎受雌二醇调节，而与雌二醇对棘突和棘突触形成的作用无关。
