Halliday G M, Törk I
School of Anatomy, University of New South Wales, Kensington, Sydney, Australia.
Brain Res Bull. 1989 Apr;22(4):725-35. doi: 10.1016/0361-9230(89)90092-0.
The distribution and morphology of serotonin-like immunoreactive (5HT-IR) nerve cells, fibres and terminals in the rat ventromedial mesencephalic tegmentum (VMT) was studied using qualitative and quantitative immunohistochemical methods at light and electron microscopic levels. All five component nuclei were examined and the size, number and density of immunoreactive neurons and terminals determined. Thirty percent of all neurons in the caudal linear nucleus and 1% in the interfascicular nucleus were immunoreactive for serotonin. Different regions of the VMT had morphologically distinct 5HT-IR fibres and quantitative differences between the VMT nuclei were seen in the density of 5HT-IR terminals. In the lateral VMT, many thick, nonvaricose 5HT-IR fibres were found in the parabrachial pigmented nucleus while many fine, varicose 5HT-IR fibres were found in the paranigral nucleus. Fine, varicose 5HT-IR fibres were also seen in the rostral and caudal linear nuclei. Many 5HT-IR axon profiles formed synapses with small calibre dendrites. 5HT-IR fibres in the interfascicular nucleus were thick with variable sized varicosities at irregular intervals. Few 5HT-IR axon profiles formed synapses in this nucleus. A comparison between the number of 5HT-IR terminals and the total number of axon terminals in the VMT (25) reveals that the majority of all terminals in the paranigral and rostral linear nuclei can be labelled with serotonin. The effect of serotonin on VMT cells is therefore likely to be mediated by different types of 5HT-IR fibres which preferentially innervate particular VMT nuclei.
采用定性和定量免疫组织化学方法，在光镜和电镜水平上研究了大鼠中脑腹内侧被盖区（VMT）中5-羟色胺样免疫反应性（5HT-IR）神经细胞、纤维和终末的分布及形态。对所有五个组成核进行了检查，并确定了免疫反应性神经元和终末的大小、数量和密度。尾侧线性核中所有神经元的30%以及束间核中1%的神经元对5-羟色胺呈免疫反应性。VMT的不同区域具有形态上不同的5HT-IR纤维，并且在5HT-IR终末的密度方面，VMT各核之间存在数量差异。在VMT外侧，臂旁色素核中发现许多粗大、无曲张的5HT-IR纤维，而黑质旁核中发现许多细小、有曲张的5HT-IR纤维。在头侧和尾侧线性核中也可见细小、有曲张的5HT-IR纤维。许多5HT-IR轴突轮廓与小口径树突形成突触。束间核中的5HT-IR纤维粗大，有大小不一的曲张，间隔不规则。在该核中很少有5HT-IR轴突轮廓形成突触。VMT中5HT-IR终末数量与轴突终末总数（25个）的比较显示，黑质旁核和头侧线性核中所有终末的大多数都可以用5-羟色胺标记。因此，5-羟色胺对VMT细胞的作用可能是由不同类型的5HT-IR纤维介导的，这些纤维优先支配特定的VMT核。
