Expression of Long-Term Plasticity at Individual Synapses in Hippocampus Is Graded, Bidirectional, and Mainly Presynaptic: Optical Quantal Analysis
Expression of Long-Term Plasticity at Individual Synapses in Hippocampus Is Graded, Bidirectional, and Mainly Presynaptic: Optical Quantal Analysis
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DOI：
10.1016/j.neuron.2009.02.026
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发表时间：
2009-04-30
期刊：
影响因子：
16.2
通讯作者：
Fine, Alan
中科院分区：
文献类型：
--
作者：
Enoki, Ryosuke;Hu, Yi-ling;Fine, Alan
尽管经过了数十年的研究，长时程增强（LTP）和长时程抑制（LTD）表达的关键方面仍未得到解决。人们认为突触后谷氨酸受体的改变有助于各种形式的LTP和LTD的表达，但突触前机制的相对重要性存在争议。此外，虽然对一个细胞的总突触输入可以经历连续的和分级的（增量的）LTP和LTD，但有人提出单个突触可能只支持在初始强度水平和改变后的强度水平之间的二元变化。我们通过将电生理方法与对青春期大鼠海马急性切片中CA1锥体神经元上单个活性（非沉默）谢弗侧支突触可塑性的双光子光学量子分析相结合来解决这些问题。我们发现这些突触维持分级的、双向的长期可塑性。值得注意的是，效能的变化很小且不显著；这些突触的长期可塑性主要通过突触前递质释放可靠性的改变来表达。
Key aspects of the expression of long-term potentiation (LTP) and long-term depression (LTD) remain unresolved despite decades of investigation. Alterations in postsynaptic glutamate receptors are believed to contribute to the expression of various forms of LTP and LTD, but the relative importance of presynaptic mechanisms is controversial. In addition, while aggregate synaptic input to a cell can undergo sequential and graded (incremental) LTP and LTD, it has been suggested that individual synapses may only support binary changes between initial and modified levels of strength. We have addressed these issues by combining electrophysiological methods with two-photon optical quantal analysis of plasticity at individual active (non-silent) Schaffer collateral synapses on CA1 pyramidal neurons in acute slices of hippocampus from adolescent rats. We find that these synapses sustain graded, bidirectional long-term plasticity. Remarkably, changes in potency are small and insignificant; long-term plasticity at these synapses is expressed overwhelmingly via presynaptic changes in reliability of transmitter release.