Slow presynaptic and fast postsynaptic components of compound long-term Potentiation
Slow presynaptic and fast postsynaptic components of compound long-term Potentiation
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DOI：
10.1523/jneurosci.3077-07.2007
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发表时间：
2007-10-24
影响因子：
5.3
通讯作者：
Zakharenko, Stanislav S.
中科院分区：
文献类型：
--
作者：
Bayazitov, Ildar T.;Richardson, Robert J.;Zakharenko, Stanislav S.
长时程增强（LTP）介导哺乳动物海马的学习和记忆。突触前或突触后神经元是否主要增强LTP期间的突触传递仍然存在争议。用在神经元中表达synaptophorin的转基因小鼠株制备急性海马切片。synaptophorin是突触囊泡循环的指标；因此，我们通过测量突触氟荧光的变化来监测CA3锥体细胞突触前钮扣的功能变化。同时，我们记录了场兴奋性突触后电位，以监测CA3和CA1锥体神经元之间兴奋性突触强度的变化。我们发现LTP由两个组成部分组成，一个是缓慢的突触前组成部分，一个是快速的突触后组成部分。突触前机制在复合LTP的后期阶段起主要作用，而突触后机制在LTP的早期阶段起关键作用。我们还发现蛋白激酶A （PKA）和l型电压门控钙通道对于复合LTP突触前组分的表达至关重要，而NMDA通道对于LTP突触后组分的表达至关重要。这些数据是第一个直接证据，证明LTP的突触前和突触后成分在时间和机制上是不同的。
Long-term potentiation (LTP) mediates learning and memory in the mammalian hippocampus. Whether a presynaptic or postsynaptic neuron principally enhances synaptic transmission during LTP remains controversial. Acute hippocampal slices were made from transgenic mouse strains that express synaptopHluorin in neurons. SynaptopHluorin is an indicator of synaptic vesicle recycling; thus, we monitored functional changes in presynaptic boutons of CA3 pyramidal cells by measuring changes in synaptopHluorin fluorescence. Simultaneously, we recorded field excitatory postsynaptic potentials to monitor changes in the strength of excitatory synapses between CA3 and CA1 pyramidal neurons. We found that LTP consists of two components, a slow presynaptic component and a fast postsynaptic component. The presynaptic mechanisms contribute mostly to the late phase of compound LTP, whereas the postsynaptic mechanisms are crucial during the early phase of LTP. We also found that protein kinase A ( PKA) and L-type voltage-gated calcium channels are crucial for the expression of the presynaptic component of compound LTP, and NMDA channels are essential for that of the postsynaptic component of LTP. These data are the first direct evidence that presynaptic and postsynaptic components of LTP are temporally and mechanistically distinct.