Localization of the M2 muscarinic cholinergic receptor in dendrites, cholinergic terminals, and noncholinergic terminals in the rat basolateral amygdala: An ultrastructural analysis.
Localization of the M2 muscarinic cholinergic receptor in dendrites, cholinergic terminals, and noncholinergic terminals in the rat basolateral amygdala: An ultrastructural analysis.
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M2 毒蕈碱胆碱能受体在大鼠基底外侧杏仁核树突、胆碱能末端和非胆碱能末端的定位：超微结构分析。
DOI：
10.1002/cne.23959
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
McDonald,AlexanderJ
中科院分区：
文献类型：
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作者：
Muller,JayF;Mascagni,Franco;Zaric,Violeta;Mott,DavidD;McDonald,AlexanderJ
大鼠前基底外侧核(BLA)M2受体(M2Rs)的激活对于巩固情绪唤起事件的记忆至关重要。本研究利用免疫细胞化学在电子显微镜水平上确定BLA中的哪些结构表达M2Rs。此外，对M2R和胆碱能轴突的标志物-囊泡乙酰胆碱转运蛋白(Vacht)进行双重定位，以确定M2R是否是支配BLA的胆碱能轴突中的自身受体。除高尔基复合体外，锥体神经元的核周膜无M2R免疫反应阳性(M2R-ir)，而发自这些神经元的近端树突和轴突起始段有密集的M2R免疫反应。大多数非锥体细胞核膜也呈M2R阴性。约95%的树突和60%的树突棘为M2免疫反应阳性(M2R+)。一些M2R+树突有棘突，提示它们属于锥体细胞，而另一些则具有典型的非锥体神经元的形态特征。M2R-ir也见于轴突终末，大部分轴突终末形成非对称性突触。M2R+终末形成非对称性(可能是兴奋性)突触的主要靶点是树突棘，其中大部分是M2R+。形成对称性(抑制性或神经调节性)突触的M2R+终末的主要靶点是未标记的核周膜和M2R+树突。Vacht+胆碱能终末也可见M2R-ir，提示可能存在自身受体作用。这些发现表明，M2R介导的BLA机制非常复杂，涉及树突的突触后效应以及调节突触前轴突终末释放谷氨酸、γ-氨基丁酸和乙酰胆碱。J.Comp.神经。2016年524：2400-2417。©2016 Wiley期刊，Inc.
Activation of M2 muscarinic receptors (M2Rs) in the rat anterior basolateral nucleus (BLa) is critical for the consolidation of memories of emotionally arousing events. The present investigation used immunocytochemistry at the electron microscopic level to determine which structures in the BLa express M2Rs. In addition, dual localization of M2R and the vesicular acetylcholine transporter protein (VAChT), a marker for cholinergic axons, was performed to determine whether M2R is an autoreceptor in cholinergic axons innervating the BLa. M2R immunoreactivity (M2R‐ir) was absent from the perikarya of pyramidal neurons, with the exception of the Golgi complex, but was dense in the proximal dendrites and axon initial segments emanating from these neurons. Most perikarya of nonpyramidal neurons were also M2R–negative. About 95% of dendritic shafts and 60% of dendritic spines were M2 immunoreactive (M2R+). Some M2R+dendrites had spines, suggesting that they belonged to pyramidal cells, whereas others had morphological features typical of nonpyramidal neurons. M2R‐ir was also seen in axon terminals, most of which formed asymmetrical synapses. The main targets of M2R+terminals forming asymmetrical (putative excitatory) synapses were dendritic spines, most of which were M2R+. The main targets of M2R+terminals forming symmetrical (putative inhibitory or neuromodulatory) synapses were unlabeled perikarya and M2R+dendritic shafts. M2R‐ir was also seen in VAChT+cholinergic terminals, indicating a possible autoreceptor role. These findings suggest that M2R‐mediated mechanisms in the BLa are very complex, involving postsynaptic effects in dendrites as well as regulating release of glutamate, γ‐aminobutyric acid, and acetylcholine from presynaptic axon terminals. J. Comp. Neurol. 524:2400–2417, 2016. © 2016 Wiley Periodicals, Inc.