Input-specific long-term potentiation in the rat lateral amygdala of horizontal slices
Input-specific long-term potentiation in the rat lateral amygdala of horizontal slices
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DOI：
10.1016/j.nlm.2005.11.004
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发表时间：
2006-05-01
影响因子：
2.7
通讯作者：
Albrecht, Doris
中科院分区：
文献类型：
--
作者：
Drephal, Christian;Schubert, Manja;Albrecht, Doris
杏仁核外侧核（LA）输入突触的长时程增强（LTP）是恐惧学习记忆储存的一种可能机制。LTP的细胞机制几乎只在冠状脑切片中进行了研究。在我们的实验中，我们使用了大鼠的水平脑切片，保留了大部分与皮层区域和海马体的连接。刺激电极位于外囊（EC）或LA内。本研究的目的是探讨弱θ波群刺激（TBS）和强高频刺激（HFS）两种不同刺激部位诱发LTP的机制。而TBS和HFS的传入纤维通过LA引起稳定的LTP，TBS未能诱导LTP的EC输入到LA。目前的研究结果还表明，LTP在LA表现出脆弱性在不同的时间窗口后诱导。时间窗依赖于刺激的传入纤维的种类。后来LTP变得抵抗低频刺激的破坏。我们可以证明，这两种使用的输入依赖于NMDA受体的LTP诱导。硝苯地平（10 μ M）不改变由刺激LA内的纤维诱导的LTP。相反，EC诱导的LTP依赖于L型电压门控钙通道（VGCC）。最后，我们发现一个更高的幅度的LTP在女性使用TBS，而HFS没有造成性别特异性差异。我们的研究支持的结论是，LA-LTP的形式取决于哪些传入纤维被激活，什么样的刺激模式被用来诱导LTP。(c)2005年爱思唯尔公司All rights reserved.
Long-term potentiation (LTP) at input synapses to the lateral nucleus of the amygdala (LA) is a candidate mechanism for memory storage during fear learning. Cellular mechanisms of LTP have been nearly exclusively investigated in coronal brain slices. In our experiments, we used a horizontal brain slice preparation of rats that preserved most of the connections to cortical areas and the hippocampus. The stimulation electrodes were located either within the external capsule (EC) or the LA. The aim of the present study was to investigate the mechanisms of LTP induced either by weak theta burst stimulation (TBS) or strong high frequency stimulation (HFS) using the two different stimulation sites. Whereas both TBS and HFS of afferences running through the LA induced stable LTP, TBS failed to induce LTP of EC-inputs to the LA. The present findings also show that LTP in the LA exhibits vulnerability at different time windows after induction. The time window was dependent on the kind of stimulated afferences. Later LTP becomes resistant to disruption by low frequency stimulation. We could show that both used inputs depended on NMDA receptors for LTP-induction. LTP induced by stimulation of fibers within the LA was not altered by nifedipine (10 mu M). In contrast, EC-induced LTP was dependent on L-type voltage-gated calcium channels (VGCC). Finally, we found a higher magnitude of LTP in females using TBS, whereas HFS did not cause gender-specific differences. Our study supports the conclusion that the form of LA-LTP depend on which afferences are activated and what pattern of stimulation is used to induce LTP. (c) 2005 Elsevier Inc. All rights reserved.