Synaptic depression in the CA1 region of freely behaving mice is highly dependent on afferent stimulation parameters.
Synaptic depression in the CA1 region of freely behaving mice is highly dependent on afferent stimulation parameters.
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DOI：
10.3389/fnint.2013.00001
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发表时间：
2013
影响因子：
3.5
通讯作者：
Manahan-Vaughan D
中科院分区：
文献类型：
--
作者：
Goh JJ;Manahan-Vaughan D
持续性突触可塑性自首次被描述以来，几十年来一直受到广泛的研究。它以长时程增强（LTP）和长时程抑制（LTD）的形式存在，与海马区依赖的持久记忆形式有许多细胞和分子特性。最近的报告都LTP和LTD发生内源性在特定的学习条件下提供了进一步的支持，这些形式的突触可塑性可能包括记忆的细胞相关。大多数突触可塑性的研究都是使用体外或体内制剂进行的，其中对传入纤维进行图案化的电刺激以诱导突触强度的变化。这种策略已被证明在诱导LTP方面非常有效，即使在体内条件下也是如此。LTD在体内已被证明更难以捉摸：虽然LTD在大鼠和小鼠的特定学习条件下内源性发生，但其诱导尚未成功地证明与传入电刺激单独。在这项研究中，我们筛选了一个大的频谱的协议，是已知的诱导LTD无论是在海马切片或在完整的大鼠海马，以澄清LTD是否可以诱导小鼠CA1区在体内的唯一传入刺激。在100至1800个脉冲范围内给予1、2、3、5、7或10 Hz的低频刺激，最多产生持续长达60分钟的短期抑制（STD）。900次脉冲，间隔5 min，或改变刺激强度，均不能改善突触抑制的持续性。在小鼠的学习条件下，LTD至少持续24小时。我们的结论是，因素的巧合，如传入活动与神经调节输入一起，在更自然的情况下（例如，学习）条件。
Persistent synaptic plasticity has been subjected to intense study in the decades since it was first described. Occurring in the form of long-term potentiation (LTP) and long-term depression (LTD), it shares many cellular and molecular properties with hippocampus-dependent forms of persistent memory. Recent reports of both LTP and LTD occurring endogenously under specific learning conditions provide further support that these forms of synaptic plasticity may comprise the cellular correlates of memory. Most studies of synaptic plasticity are performed using in vitro or in vivo preparations where patterned electrical stimulation of afferent fibers is implemented to induce changes in synaptic strength. This strategy has proven very effective in inducing LTP, even under in vivo conditions. LTD in vivo has proven more elusive: although LTD occurs endogenously under specific learning conditions in both rats and mice, its induction has not been successfully demonstrated with afferent electrical stimulation alone. In this study we screened a large spectrum of protocols that are known to induce LTD either in hippocampal slices or in the intact rat hippocampus, to clarify if LTD can be induced by sole afferent stimulation in the mouse CA1 region in vivo. Low frequency stimulation at 1, 2, 3, 5, 7, or 10 Hz given in the range of 100 through 1800 pulses produced, at best, short-term depression (STD) that lasted for up to 60 min. Varying the administration pattern of the stimuli (e.g., 900 pulses given twice at 5 min intervals), or changing the stimulation intensity did not improve the persistency of synaptic depression. LTD that lasts for at least 24 h occurs under learning conditions in mice. We conclude that a coincidence of factors, such as afferent activity together with neuromodulatory inputs, play a decisive role in the enablement of LTD under more naturalistic (e.g., learning) conditions.