猫丘脑中央外侧核内丘脑皮质投射神经元的超微结构及其突触联系——HRP法电镜研究

本文应用HRP逆行追踪法在电镜水平上对猫丘脑中央外侧核内皮质投射神经元的超微结构及其突触联系首次进行了研究,该核内皮质投射神经元以中型多见,胞核较大,核仁清晰,偏位,核膜有凹陷,常染色质较多,胞质内含丰富的线粒体、游离核糖体和粗面内质网,标记树突直径变化较大,从0.68μm到4.4μm,含较多的线粒体、微管及滑面内质网,未见突触小泡,标记的皮质投射神经元胞体和树突做为突触后成份,与非标记的突触前成份形成下列突触:①轴-树突触,突触前轴突终末以SR型和F型居多;②轴-体突触,突触前终末中有F型和RF型;③树-树突触;④轴-轴-树突触;⑤突触复合体,许多标记树突做为中央树突参与形成汇聚型突触复合体。

The Ultrastructure and Synaptic Connections of the Thalamocortical ProfectingNeurons in the Thalamic Central Lateral Nucleus of the Cat-An ElectronMicorscopic Study with HRP Method

The ultrastructure and synaptic connections of the thalamocortical projecting neurons (TCPNs) in the thalamic central lateral nucleus (CL) were studied by using HRP retrograde tracing method and electron microscope. The labelled TCPNs are common in middle styles and characterized by a large nucleus and abundant cytoplsm with a large amount of free ribosome, rough surfaced endoplasmic reticula and mitochondria. The nuclei have infolded nuclear membran and contain much more enchromatin. The diameter of the labelled TCPN's dendrites, which contain more mitochondria, microtubules and smooth surfaced endoplasmic reticulas, is from 0.68μm to 4.4 μm. No synaptic vesicles are found in the labelled dendrites. The labelled dendrites and somas of the TCPNs make following synapses with nulabelled presynaptic elements: (1) axo - dendritic synapses, the 'SR' and ' F' styles are common in the presynaptic axonal terminals; (2) axo-somatic synapses, the 'F' and 'RF' styles can be found in the presynaptic axonal terminals; (3) dendro-dendritic synapses; (4) axo - axo - dendritic synapses. The labelled dendrites take part in convergent synaptic complex in which the labeleed dendrite is surrounded by unlabelled presynaptic terminals.