ELEMENTAL AND STRUCTURAL ORGANIZATION OF NEURONS AND GLIA

本项目研究钙的生理和发育。 树突和树突中突触活动的调节 中枢神经系统神经元的脊椎。以前，分析和 使用一种新型的海马片培养的结构工作 以内质网的一个亚群为主要钙- CA3神经元树突内的隔离细胞器 在传入突触活动之后。我们现在已经确定 这些钙缓冲细胞器即使不完全相同，也非常相似， 在其他时间起到储存和释放钙的作用 细胞器。研究发现，这些细胞器具有钙的作用。 在1-15分钟的时间范围内设立封存地点，而 线粒体钙隔离与内质网摄取并行运行 仅在突触活动后的第一分钟内。类似的证据 对于强大的线粒体来说，钙隔离已经从 蛙交感神经节分离神经元的新研究。 在此之前，我们已经证明雌激素使树突棘密度增加一倍。 在培养的CA1海马神经元中，从而提供了一种诱人的 解释最近发现的雌激素影响认知和 成体生物的可塑性。使用激酶抑制剂的新实验， 反义寡核苷酸和特异性抗体与 高分辨率共聚焦显微镜现在显示cAMP反应 元件结合蛋白(CREB)必须通过cAMP-1被磷酸化。 依赖蛋白激酶A和CREB结合蛋白(CBP)， 在脊椎发育之前。这表明基因组激活到 转录脊椎蛋白可能是新脊柱发育所必需的。在……里面 关于雌二醇间接作用的平行实验发现 这种激素降低谷氨酸脱羧酶(GAD)的抑制作用 海马神经元，从而减少数量和可获得性 神经递质GABA。这有效地改变了 锥体神经元的兴奋/抑制，细胞内增加 钙，进而导致CREB的磷酸化和合成 新的脊椎。研究结果表明， 雌二醇可以提供一种有效而短暂的方式来控制兴奋性。 活性和形态可塑性。

This project studies the physiology and development of calcium regulation during synaptic activity in the dendrites and dendritic spines of central nervous system neurons. Previously, analytical and structural work using a new type of hippocampal slice culture had characterized a subset of endoplasmic reticulum as the major calcium- sequestering organelle in dendrites of CA3 neurons in the minutes following the afferent synaptic activity. We have now established that these calcium-buffering organelles are very similar, if not identical, to those which at other times act as calcium storage and release organelles. It is found that these organelles function as calcium sequestration sites within a time frame of <1-15 minutes, while mitochondrial calcium sequestration operates in parallel with ER uptake only over the first minute following synaptic activity. Similar evidence for robust mitochondrial calcium sequestration has been obtained from a new study on isolated neurons from frog sympathetic ganglia. Previously we had shown that estradiol doubles dendritic spine density in cultures of CA1 hippocampal neurons, thus providing an attractive explanation for the recent discovery that estrogen affects cognition and plasticity in adult organisms. New experiments using kinase inhibitors, antisense oligonucleotides, and specific antibodies in combination with high-resolution confocal microscopy now show that the cAMP response element binding protein (CREB) is necessarily phosphorylated via cAMP- dependent protein kinase A, and CREB binding protein (CBP) is recruited, prior to spine development. This indicates that genome activation to transcribe spine proteins may be required for new spine development. In parallel experiments on the indirect effects of estradiol, it was found that this hormone lowers glutamic acid decarboxylase (GAD) in inhibitory hippocampal interneurons, thus decreasing the amount and availability of the neurotransmitter GABA. This effectively changes the balance of excitation/inhibition in pyramidal neurons, increasing intracellular calcium which may in turn cause phosphorylation of CREB and synthesis of new spines. The findings suggest that the indirect effects of estradiol can provide a powerful yet transient way to control excitatory activity and morphological plasticity.