Metabotropic glutamate receptor 8-expressing nerve terminals target subsets of GABAergic neurons in the hippocampus
Metabotropic glutamate receptor 8-expressing nerve terminals target subsets of GABAergic neurons in the hippocampus
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DOI：
10.1523/jneurosci.2547-05.2005
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发表时间：
2005-11-09
影响因子：
5.3
通讯作者：
Dalezios, Y
中科院分区：
文献类型：
--
作者：
Ferraguti, F;Klausberger, T;Dalezios, Y
突触前代谢型谷氨酸受体（mGluRs）在神经末梢中显示高度选择性表达和亚细胞定位，调节神经递质的释放。我们已经证明，mGluR 8，mGluR 8a和mGluR 8b的选择性剪接变体在海马中具有重叠分布，并且除了穿通通路末端，它们在终扣的突触前活性区中表达，从而选择性地与几种类型的GABA能中间神经元形成突触，主要在定向层中。标记为mGluR 8的结形成I型或II型突触，后者是GABA能的。一些mGluR 8阳性终末也表达mGluR 7或血管活性肠多肽。中间神经元强烈免疫阳性的毒蕈碱M2或mGlu 1受体的mGluR 8-含终端在层oriens的主要目标，但只有神经化学不同的子集受神经支配的mGluR 8丰富的终端。大多数的M2阳性神经元mGluR 8支配，但少数，表达生长抑素，没有。罕见的神经元共表达calretinin和M2一致的mGluR 8阳性终扣的目标。在体内记录和标记的mGluR 8装饰和强烈的M2阳性中间神经元显示了一个三层细胞与复杂的尖峰脉冲在θ振荡和强烈的放电过程中的尖锐波/涟漪事件。三层细胞有一个大的投影从CA 1区的下托和一个优先的神经支配的中间神经元在CA 1区除了锥体细胞胞体和树突。突触后interneuron类型特异性表达的高效能突触前mGluR 8在推定的谷氨酸能和确定的GABA能终端预测的作用，在调整的活动，interneuron取决于网络活动的水平。
Presynaptic metabotropic glutamate receptors (mGluRs) show a highly selective expression and subcellular location in nerve terminals modulating neurotransmitter release. We have demonstrated that alternatively spliced variants of mGluR8, mGluR8a and mGluR8b, have an overlapping distribution in the hippocampus, and besides perforant path terminals, they are expressed in the presynaptic active zone of boutons making synapses selectively with several types of GABAergic interneurons, primarily in the stratum oriens. Boutons labeled for mGluR8 formed either type I or type II synapses, and the latter were GABAergic. Some mGluR8-positive boutons also expressed mGluR7 or vasoactive intestinal polypeptide. Interneurons strongly immunopositive for the muscarinic M2 or the mGlu1 receptors were the primary targets of mGluR8-containing terminals in the stratum oriens, but only neurochemically distinct subsets were innervated by mGluR8-enriched terminals. The majority of M2-positive neurons were mGluR8 innervated, but a minority, which expresses somatostatin, was not. Rare neurons coexpressing calretinin and M2 were consistently targeted by mGluR8-positive boutons. In vivo recording and labeling of an mGluR8-decorated and strongly M2-positive interneuron revealed a trilaminar cell with complex spike bursts during theta oscillations and strong discharge during sharp wave/ripple events. The trilaminar cell had a large projection from the CA1 area to the subiculum and a preferential innervation of interneurons in the CA1 area in addition to pyramidal cell somata and dendrites. The postsynaptic interneuron type-specific expression of the high-efficacy presynaptic mGluR8 in both putative glutamatergic and in identified GABAergic terminals predicts a role in adjusting the activity of interneurons depending on the level of network activity.