α2A-adrenergic receptors are present in μ-opioid receptor containing neurons in rat medial nucleus tractus solitarius
α2A-adrenergic receptors are present in μ-opioid receptor containing neurons in rat medial nucleus tractus solitarius
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DOI：
10.1002/syn.10036
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发表时间：
2002-03-01
期刊：
影响因子：
2.3
通讯作者：
Pickel, VM
中科院分区：
文献类型：
--
作者：
Glass, MJ;Pickel, VM
α-2A-肾上腺素能-（α（2A）-AR）和μ-阿片受体（muOR）的激动剂共同影响自主神经功能，所述自主神经功能在经历从长期施用muOR激动剂吗啡戒断的动物中也失调。心血管和胃肠道反射部分由孤束内侧核（mNTS）在尾侧（cNTS）和中间（iNTS）亚区介导。总之，这一证据表明，α（2A）-AR和muOR可以共定位在许多相同的神经元配置文件中的中间和尾部mNTS。为了检查α（2A）-AR和muOR是否存在于共同的胞体，树突，或轴突终末的mNTS，我们使用电子显微镜免疫细胞化学检测抗血清对每个受体在中间和尾部水平的这个大脑区域。大多数的双重标记的轮廓是胞体和树突。在iNTS的所有双标记谱中，49%是胞体，47%是树突，而在cNTS中，61%是胞体，32%是树突。在双标记谱中，α（2A）-AR和muOR的细胞内分布不同。muOR更常与质膜相关，而α（2A）-AR通常与囊泡细胞器相关。少数轴突终端，甚至更少的神经胶质细胞，包含这两个标记。我们还经常观察到单标记的α（2A）-AR神经胶质细胞，专门贴附muOR含树突或轴突终端。这些发现表明，胞体和树突含有会聚muOR和α（2A）-AR激活的功能位点。此外，每个受体的位置参与并列的神经元和神经胶质细胞之间的细胞间信号传导。α（2A）-AR在含muOR的胞体或树突上或在与含muOR的神经元并列的神经胶质上的激活可能有助于解释α（2A）-AR激动剂在缓解阿片类戒断的一些自主症状中的疗效。Synapse 43：208-218，2002. (C)2002 Wiley-Liss，Inc.
Agonists of the alpha-2A-adrenergic- (alpha(2A)-AR) and the mu-opioid-receptor (muOR) jointly affect autonomic functions that are also disregulated in animals undergoing withdrawal from chronic administration of the muOR agonist morphine. Cardiovascular and gastrointestinal reflexes are mediated, in part, by the medial nucleus of the solitary tract (mNTS) at caudal (cNTS) and intermediate (iNTS) subregions. Together, this evidence suggests that alpha(2A)-AR and muOR may be colocalized within many of the same neuronal profiles in both the intermediate and caudal mNTS. In order to examine whether alpha(2A)-AR and muOR are present within common somata, dendrites, or axon terminals in the mNTS, we used electron microscopic immunocytochemistry for the detection of antisera against each receptor at intermediate and caudal levels of this brain region. Most of the dually labeled profiles were somata and dendrites. Of all dual-labeled profiles in the iNTS 49% were somata and were 47% dendrites, whereas in the cNTS 61% were somata and 32% were dendrites. Within dual-labeled profiles, the intracellular distribution of alpha(2A)-AR and muOR differed. muOR was more frequently associated with the plasmalemma, whereas alpha(2A)-AR was often affiliated with vesicular organelles. Few axon terminals, and even fewer glia, contained both markers. We also frequently observed single-labeled alpha(2A)-AR glia that apposed exclusively muOR-containing dendrites or axon terminals. These findings indicate that somata and dendrites contain functional sites for convergent muOR and alpha(2A)-AR activation. In addition, each receptor is positioned for involvement in intercellular signaling between apposed neurons and glia. Activation of alpha(2A)-AR on muOR-containing somata or dendrites, or on glia apposed to muOR-containing neurons, may help to account for the efficacy of alpha(2A)-AR agonists in relieving some of the autonomic symptoms of opiate withdrawal. Synapse 43:208-218, 2002. (C) 2002 Wiley-Liss, Inc.