Rapid brain-derived neurotrophic factor-dependent sequestration of amygdala and hippocampal GABA(A) receptors via different tyrosine receptor kinase B-mediated phosphorylation pathways.
Rapid brain-derived neurotrophic factor-dependent sequestration of amygdala and hippocampal GABA(A) receptors via different tyrosine receptor kinase B-mediated phosphorylation pathways.
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DOI：
10.1016/j.neuroscience.2010.12.041
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发表时间：
2011-03-10
期刊：
影响因子：
3.3
通讯作者：
Ressler KJ
中科院分区：
文献类型：
--
作者：
Mou L;Heldt SA;Ressler KJ
在恐惧记忆的巩固过程中，已经表明杏仁核中的GABAA受体（GABAAR）迅速下调。这种GABAAR功能的快速下降可能允许短暂的过度兴奋，有助于记忆巩固的细胞机制。记忆巩固还需要BDNF激活杏仁核和海马体中的TrkB受体。我们假设GABAAR α 1的快速内化是通过TrkB激活PKA和PKC依赖性过程介导的。原代神经元细胞培养，从出生后第14 - 21天的小鼠杏仁核和海马，进行了分析与免疫荧光使用细胞表面，全细胞透化，抗体内化技术，以及与3H-蝇蕈醇结合试验。在海马和杏仁核培养物中，我们发现BDNF处理5分钟内表面GABAAR α 1减少> 60%。值得注意的是，表面GABAAR α 1的快速减少通过表面生物素化试验和蛋白质印迹法进行生物化学证实。这种快速作用伴随着TrkB磷酸化和增加的内部GABAAR α 1免疫荧光，并被广谱酪氨酸激酶拮抗剂k252a阻断。为了进一步证明TrkB特异性，我们使用了先前表征的TrkBF 616 A小鼠，其中高度选择性的TrkB突变体特异性拮抗剂1NMPP1阻止了BDNF依赖性GABAAR α 1的内化。在海马中，我们发现分别使用Rp-8-Br-cAMP和Calphostin C抑制PKA和PKC可阻断GABAAR α 1的内化，而抑制MAPK（U0126）和PI3K（LY294002）不能阻止快速内化。相反，在杏仁核培养物中，Rp-8-Br-cAMP没有影响。总之，这些数据表明，在记忆巩固期间快速GABAAR内化是BDNF-TrkB依赖的。此外，海马GABAAR内化似乎是PKA和PKC依赖性的，而杏仁核中可能主要是PKC依赖性的，这意味着TrkB依赖性激酶激活在BDNF依赖性记忆形成中的不同作用。
During the consolidation of fear memory, it has been shown that GABAA receptors (GABAAR) are rapidly downregulated in amygdala. This rapid decrease in GABAAR functioning may permit transient hyperexcitablity, contributing to cellular mechanisms of memory consolidation. Memory consolidation also requires BDNF activation of TrkB receptors in the amygdala and hippocampus. We hypothesized that rapid internalization of GABAARα1 is mediated via TrkB activation of PKA and PKC-dependent processes. Primary neuronal cell cultures, from postnatal day 14–21 mouse amygdala and hippocampus, were analyzed with immunofluorescence using cell-surface, whole-cell permeabilization, and antibody internalization techniques, as well as with 3H-muscimol binding assays. In both hippocampal and amygdala cultures, we found a >60% reduction in surface GABAARα1 within 5 minutes of BDNF treatment. Notably, the rapid decrease in surface GABAARα1 was confirmed biochemically using surface biotinylation assays followed by western blotting. This rapid effect was accompanied by TrkB phosphorylation and increased internal GABAARα1 immunofluorescence, and was blocked by k252a, a broad-spectrum tyrosine kinase antagonist. To further demonstrate TrkB specificity, we used previously characterized TrkBF616A mice, in which the highly selective TrkB-mutant specific antagonist, 1NMPP1, prevented the BDNF-dependent GABAARα1 internalization. In hippocampus, we found both PKA and PKC inhibition, using Rp-8-Br-cAMP and Calphostin C, respectively, blocked GABAARα1 internalization, whereas inhibition of MAPK (U0126) and PI3K (LY294002) did not prevent rapid internalization. By contrast in amygdala cultures, Rp-8-Br-cAMP had no effect. Together, these data suggest that rapid GABAAR internalization during memory consolidation is BDNF-TrkB dependent. Further, it appears that hippocampal GABAAR internalization is PKA and PKC dependent, while it may be primarily PKC dependent in amygdala, implying differential roles for TrkB-dependent kinase activation in BDNF-dependent memory formation.