Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California 94158, USA.
J Neurosci. 2013 Aug 14;33(33):13312-9. doi: 10.1523/JNEUROSCI.0678-13.2013.
The extensive dendritic arbor of a pyramidal cell introduces considerable complexity to the integration of synaptic potentials. Propagation of dendritic potentials is largely passive, in contrast to regenerative axonal potentials that are maintained by voltage-gated sodium channels, leading to a declination in amplitude as dendritic potentials travel toward the soma in a manner that disproportionally affects distal synaptic inputs. To counteract this amplitude filtering, Schaffer collateral synapses onto CA1 pyramidal cells contain a varying number of AMPA receptors (AMPARs) per synapse that increases with distance from the soma, a phenomenon known as distance-dependent scaling. Here, we undertake an investigation into the molecular mechanisms of distance-dependent scaling. Using dendritic recordings from rat pyramidal neurons, we confirm the basic scaling phenomenon and find that it is expressed and can be manipulated cell autonomously. Finally, we show that it depends on the presence of both a reserve pool of AMPARs and the AMPAR subunit GluA2.
树突状树突的广泛分支为突触电位的整合带来了相当大的复杂性。与由电压门控钠通道维持的再生轴突电位相反，树突状电位的传播在很大程度上是被动的，这导致随着树突状电位向胞体传播，幅度逐渐降低，这种方式不成比例地影响远端突触输入。为了抵消这种幅度滤波，Schaffer 侧枝突触到 CA1 锥体神经元的每个突触中含有数量不等的 AMPA 受体 (AMPAR)，这些受体从胞体的距离增加而增加，这种现象称为距离依赖性缩放。在这里，我们对距离依赖性缩放的分子机制进行了研究。使用来自大鼠锥体神经元的树突状记录，我们证实了基本的缩放现象，并发现它可以自主表达和操纵。最后，我们表明它依赖于 AMPAR 储备池和 AMPAR 亚基 GluA2 的存在。
