Jankowska E, Maxwell D J, Dolk S, Krutki P, Belichenko P V, Dahlström A
Department of Physiology and Pharmacology, Göteborg University, Sweden.
Neuroscience. 1995 Jul;67(2):477-87. doi: 10.1016/0306-4522(95)00059-r.
Contacts between serotoninergic nerve fibres and dorsal horn dorsal spinocerebellar tract neurons were analysed in order to investigate the morphological basis of actions of serotonin upon dorsal spinocerebellar tract neurons. In a series of experiments dorsal spinocerebellar tract neurons were labelled with intracellularly injected rhodamine-dextran in the cat. The neurons were monosynaptically excited by group II muscle afferents and cutaneous afferents and were identified by antidromic activation following stimuli applied in the cerebellum. In the second series of experiments dorsal spinocerebellar tract neurons were labelled by retrograde transport of Fluorogold injected into the cerebellum in the rat. In both series, serotoninergic fibres were labelled by using a specific anti-serotonin antiserum and were revealed by immunofluorescence. Appositions between the serotoninergic fibres and the cells were inspected with a dual channel confocal microscope. The merged images obtained with the two channels of the microscope were viewed in single optical planes 2 microns apart and in rotated three-dimensional reconstructions. Serotoninergic nerve fibres were found in apposition to cell bodies of all feline dorsal spinocerebellar tract neurons (n = 7) and of 75% of rat dorsal spinocerebellar tract neurons (n = 90). The numbers of putative contacts on cell bodies varied between less than 100 and nearly 300 (mean 160) in the cat and between about five and 30 in the rat. Contacts with dendrites of feline neurons were seen on 96% of 72 dendrites within 300 microns from soma and on 91% of 23 dendrites at distances of 300-500 microns. The number of such contacts varied from less than five to 150 on a single dendrite within these ranges of distances. Their total number within 100 microns from the soma was comparable or exceeded the number of contacts on the soma.
为了研究5-羟色胺对脊髓背小脑束神经元作用的形态学基础，对5-羟色胺能神经纤维与脊髓背角脊髓背小脑束神经元之间的接触进行了分析。在一系列实验中，用细胞内注射罗丹明-葡聚糖的方法标记猫的脊髓背小脑束神经元。这些神经元由Ⅱ类肌传入纤维和皮肤传入纤维单突触兴奋，并通过在小脑施加刺激后的逆向激活来识别。在第二系列实验中，通过向大鼠小脑注射荧光金的逆行转运来标记脊髓背小脑束神经元。在这两个系列中，使用特异性抗5-羟色胺抗血清标记5-羟色胺能纤维，并通过免疫荧光显示。用双通道共聚焦显微镜检查5-羟色胺能纤维与细胞之间的并置情况。用显微镜的两个通道获得的合并图像在相隔2微米的单个光学平面以及旋转的三维重建中观察。发现5-羟色胺能神经纤维与所有猫脊髓背小脑束神经元（n = 7）以及75%的大鼠脊髓背小脑束神经元（n = 90）的细胞体并置。猫的细胞体上假定接触的数量在不到100个到近300个之间（平均160个），大鼠的则在约5个到30个之间。在距猫神经元胞体300微米内的72个树突中有96%观察到与树突的接触，在300 - 500微米距离的23个树突中有91%观察到。在这些距离范围内，单个树突上这种接触的数量从不到5个到150个不等。在距胞体100微米内它们的总数与细胞体上接触的数量相当或超过了细胞体上接触的数量。
