Organization and synaptic ultrastructure of glomeruli in the antennal lobes of the moth Manduca sexta: a study using thin sections and freeze-fracture
Organization and synaptic ultrastructure of glomeruli in the antennal lobes of the moth Manduca sexta: a study using thin sections and freeze-fracture
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蛾天蛾触角叶肾小球的组织和突触超微结构：利用薄片和冷冻断裂的研究
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
J. Hildebrand
中科院分区：
文献类型：
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作者：
L. Tolbert;J. Hildebrand
天蛾触角叶的大脑包括一个中心区域的粗糙神经元周围的致密，球状肾小球，在那里所有的触角神经轴突和二级神经元的叶之间的突触相互作用发生。肾小球中的神经元相互作用是复杂的，涉及几种类型的神经炎的配置文件和介导的突触与一对多的比例的前突触后的元素。在肾小球中的突触前分布已被分为三种类型，分别包含圆形透明小泡、大量的大致密核心小泡和多形透明小泡。对充满辣根过氧化物酶的轴突和神经元的初步研究表明，触角神经轴突形成的突触没有大量的致密核心囊泡，触角叶神经元不仅接受突触，而且还可能与触角叶中的其他元件形成突触。一个典型的突触接触包括多个突触后元件成对地与一个单独的突触前元件并列。突触前元件包含一个棒状的膜相关密度，它沿着膜上的浅槽，两侧是突触小泡。突触后元件在突触杆的对面区域由膜相关密度排列，并且可以观察到参与串联突触。肾小球神经元的冷冻断裂复制品包含许多被认为是突触前的膜特化，其中一些类似于脊椎动物兴奋性突触。在这些明显的突触前区域，大颗粒聚集在膜的P面，通常被质膜变形包围，推测代表外吞或内吞作用的位点。突触前膜特化的主要类型（斑块）的形状与突触前膜相关密度（条形）的形状不匹配;这就提出了囊泡释放发生在沿突触前条形沿着孤立的“活动区”的可能性。突触后位点由突触后膜E面的大颗粒簇表示。
The antennal lobe of the brain of Manduca sexta comprises a central area of coarse neuropil surrounded by dense, spheroidal glomeruli, where all synaptic interactions between antennal-nerve axons and the second-order neurons of the lobe occur. Neuronal interactions in the glomeruli are complex, involving several types of neuritic profiles and mediated by synapses with a one-to-many ratio of pre- to postsynaptic elements. Presynaptic profiles in the glomeruli have been categorized into three types, containing round clear vesicles, large numbers of large dense-cored vesicles, and pleiomorphic clear vesicles, respectively. Preliminary studies of horseradish peroxidase-filled axons and neurons indicate that antennal-nerve axons form synapses without large numbers of dense-cored vesicles and that antennal-lobe neurons not only receive synapses but also may synapse onto other elements in the antennal lobe. A typical synaptic contact involves multiple postsynaptic elements apposed in pairs to an individual presynaptic element. The presynaptic element contains a bar-shaped membrane-associated density, which follows a shallow groove in the membrane and is flanked by synaptic vesicles. Postsynaptic elements are lined by membrane-associated densities in the region opposite to the synaptic bar, and may be observed to participate in serial synapses. Freeze-fracture replicas of the glomerular neuropil contain many membrane specializations that are thought to be presynaptic, some of which resemble those of vertebrate excitatory synapses. At these apparently presynaptic regions, large particles cluster in the P face of the membrane and are often surrounded by plasmalemmal deformations presumably representing sites of exo- or endocytosis. The shape of the predominant type of presynaptic membrane specialization (a plaque) does not match the shape of the presynaptic membrane-associated density (a bar); this raises the possibility that vesicle release occurs at isolated ‘active zones’ along the presynaptic bar. Postsynaptic sites are represented by clusters of large particles in the E face of the postsynaptic membrane.