Calcium signals in long-term potentiation and long-term depression
Calcium signals in long-term potentiation and long-term depression
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DOI：
10.1139/cjpp-77-9-722
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发表时间：
1999-09-01
影响因子：
2.1
通讯作者：
Otani, S
中科院分区：
文献类型：
--
作者：
Connor, JA;Petrozzino, J;Otani, S
我们描述了突触后Ca 2+信号，有助于诱导两种形式的神经元可塑性，长时程增强（LTP）和长时程抑制（LTD），在大鼠海马神经元。常见的诱导协议LTP，1秒，50赫兹强直，产生Ca 2+增加约50 μ M的树突棘的CA 1神经元。这些非常大的增加，使用低亲和力指示剂（镁呋喃5），只发现在棘和三级树突，并依赖于通过N-甲基-D-天冬氨酸（NMDA）门控通道流入。高亲和力Ca 2+指示剂（例如，Fura 2）无法证明这些事件。在急性切片中，相邻的树突分支对破伤风的反应往往非常不同，在某些情况下，同一树突上的相邻棘的反应也不同。LTD在成熟的CA 1神经元诱导的低频刺激协议（2 Hz，900脉冲），在GABA和NMDA受体阻滞剂的存在下。该LTD方案产生< 1 μ M的树突状Ca 2+增加。Ca 2+增加的持续时间与30 s相似，是由于电压门控Ca 2+内流。最后，在CA 3神经元中研究了突触寻址的Ca 2+商店释放Ca 2+的能力，发现需要立即预加载和高强度突触前刺激，与正常LTP-LTD协议不同的条件。
We describe postsynaptic Ca2+ signals that subserve induction of two forms of neuronal plasticity, long-term potentiation (LTP) and long-term depression (LTD), in rat hippocampal neurons. The common induction protocol for LTP, a 1-s, 50-Hz tetanus, generates Ca2+ increases of about 50 mu M in dendritic spines of CA1 neurons. These very large increases, measured using a low affinity indicator (Mg fura 5), were found only in the spines and tertiary dendrites, and were dependent upon influx through N-methyl-D-aspartate (NMDA) gated channels. High affinity Ca2+ indicators (e.g., fura 2) are unable to demonstrate these events. In acute slices, neighboring dendritic branches often showed very different responses to a tetanus, and in some instances, neighboring spines on the same dendrite responded differently. LTD in mature CA1 neurons was induced by a low frequency stimulus protocol (2 Hz, 900 pulses), in the presence of GABA- and NMDA-receptor blockers. This LTD protocol produced dendritic Ca2+ increases of < 1 mu M. Duration of the Ca2+ increase was similar to 30 s and was due to voltage-gated Ca2+ influx. Finally, the ability of synaptically addressed Ca2+ stores to release Ca2+ was studied in CA3 neurons and was found to require immediate preloading and high intensity presynaptic stimulation, conditions unlike normal LTP-LTD protocols.