猫丘脑腹后外侧核内皮质投射神经元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腹后外侧核内皮质投射神经元的超微结构及其突触联系进行了研究。该核内投射神经元超微结构特点为胞核较大,核仁清晰,核膜常有凹陷,常染色质较多,异染色质较少,胞浆丰富,含有大量的游离核糖体、粗面内质网及线粒体。标记的皮质投射神经元胞体和树突与非标记轴突形成轴-体突触和轴-树突触;标记树突还可以和突触前树突形成树-树突触,并做为中央树突参与形成汇聚型突触复合体。此外在标记的胞体与非标记的树突之间,标记的树突与非标记的树突之间,两标记的树突之间还存在着非突触丝状连接。

THE ULTRASTRUCTURE AND SYNAPTIC CONNECTIONS OF THE THALAMOCORTICAL PROJECTING NEURONS IN THE VENTROPOSTEROLATERAL THALAMIC NUCLEUS OF THE CAT-AN ELECTRON MICROSCOPIC STUDY WITH HRP METHOD

The ultrastructure and synaptic connections of the thalamocortical projecting neurons (TPNs) in the ventroposterolateral thalamic nucleus (VPL) were studied by using HRP retrograde tracing method. When HRP was injected into the somatosensory cortical areas of neck, trunk and limbs (posterior sigmoid gyrus), the labelled TPNs were observed with electron microscope. The labelled TPNs are characterized by large nuclei with infolded nuclear membrane containing much euchromatin and abundant cytoplasm with a large amount of free ribosomes, rough endoplasmic reticula and mitochondria. The labelled soma and dendrites of the TPNs usually make axe-somatic and axo-dendritic synapses with unlabelled axonal terminals. The labelled dendrites also make dendrodendritic synapses with unlabelled presynaptie dendrites and take part in convergent synaptic complex in which the labelled dendrite is surrounded by unlabelled axonal terminals. In addition, filamentous contacts are found between two labelled dendrites, labelled dendrite and unlabelled dendrite, as well as labelled neuronal soma and unlabelled dendrite.