Dubé L, Smith A D, Bolam J P
Department of Pharmacology, Oxford, England.
J Comp Neurol. 1988 Jan 22;267(4):455-71. doi: 10.1002/cne.902670402.
In order to determine what types of neurons in the striatum receive direct synaptic input from corticostriatal and thalamostriatal fibres and whether these afferents converge on individual striatal neurons, double anterograde labelling of axon terminals was combined with Golgi impregnation at both the light and electron microscopic levels. The area of the central neostriatum that receives input from both the parafascicular nucleus of the thalamus and the somatosensory cortex was identified by retrograde transport of a conjugate of horseradish peroxidase and wheat germ agglutinin (HRP-WGA). The same region of the neostriatum was studied in rats that had received multiple electrolytic lesions in the somatosensory cortex and also an injection of HRP-WGA in different parts of the parafascicular nucleus. Sections of this part of the neostriatum were impregnated by the single-section Golgi procedure after revealing anterogradely transported HRP-WGA. Twelve Golgi-impregnated spiny neurons were recovered and examined in the light and electron microscope after gold-toning. Ten of these neurons were typical very densely spiny medium-size neurons and they were all found to receive asymmetric synaptic input on dendritic spines from degenerating corticostriatal boutons. However, even though numerous boutons labelled anterogradely by HRP-WGA from the parafascicular nucleus were found within the dendritic fields of neurons that received cortical input, none of the terminals from the thalamus made synaptic contact with these neurons. Instead, all 96 thalamostriatal boutons studied were found in asymmetric synaptic contact with dendritic shafts of other neurons. Two such neurons that received input from the parafascicular nucleus were Golgi-impregnated and appeared to be medium-size spiny neurons, but they had a lower density of spines than the typical very densely spiny neurons. An independent confirmation that the targets of thalamostriatal neurons originating in the parafascicular nucleus are dendritic shafts was provided by studying the boutons labelled following electrolytic lesioning or injection of the lectin Phaseolus vulgaris-leucoagglutinin (PHA-L) into this nucleus: these boutons were also found to form asymmetric synaptic contacts with dendritic shafts within the neostriatum. It is concluded that although afferents from the somatosensory cortex and from the parafascicular nucleus converge upon the same part of the neostriatum, they probably do not converge upon the same spiny neurons.(ABSTRACT TRUNCATED AT 400 WORDS)
为了确定纹状体内哪些类型的神经元接受来自皮质纹状体和丘脑纹状体纤维的直接突触输入，以及这些传入纤维是否汇聚于单个纹状体神经元，在光学和电子显微镜水平上，将轴突终末的双重顺行标记与高尔基染色法相结合。通过辣根过氧化物酶与小麦胚凝集素（HRP-WGA）的复合物逆行运输，确定了接受来自丘脑束旁核和体感皮层输入的新纹状体中央区域。在体感皮层接受多次电解损伤且在束旁核不同部位注射HRP-WGA的大鼠中，对同一新纹状体区域进行了研究。在显示顺行运输的HRP-WGA后，用单切片高尔基法对该部分新纹状体切片进行染色。经金调色后，在光学和电子显微镜下观察并恢复了十二个高尔基染色的棘状神经元。其中十个神经元是典型的棘突非常密集的中等大小神经元，并且发现它们都在树突棘上接受来自退化的皮质纹状体终扣的不对称突触输入。然而，尽管在接受皮质输入的神经元树突区域内发现了许多由HRP-WGA顺行标记的来自束旁核的终扣，但来自丘脑的终末与这些神经元没有形成突触联系。相反，所研究的所有96个丘脑纹状体终扣都与其他神经元的树突干形成了不对称突触联系。通过研究在束旁核进行电解损伤或注射菜豆凝集素（PHA-L）后标记的终扣发现，来自束旁核的丘脑纹状体神经元的靶标是树突干，这为上述结果提供了独立验证：这些终扣也被发现与新纹状体内树突干形成不对称突触联系。得出的结论是，尽管来自体感皮层和束旁核的传入纤维汇聚于新纹状体的同一部分，但它们可能不会汇聚于同一棘状神经元。（摘要截取自400字）
