Villar M J, Vitale M L, Hökfelt T, Verhofstad A A
Department of Histology and Neurobiology, Karolinska Institutet, Stockholm, Sweden.
J Comp Neurol. 1988 Nov 1;277(1):126-40. doi: 10.1002/cne.902770109.
Injections of HRP into the superior colliculus labelled cells in the lateral cell groups of the dorsal raphe nucleus. The cytoarchitectural features and location of these cells showed remarkable similarities with those known to project to the lateral geniculate body, and, therefore, the possible existence of branching neurons in the dorsal raphe nucleus projecting to these two visual structures was tested. Injections into the lateral geniculate body and the superior colliculus of several fluorescent tracers--namely, Fast Blue, Fluoro-Gold, propidium iodide, rhodamine-B-isothiocyanate, and Diamidino Yellow, used in different combinations, showed single- and double-labelled neurons in the lateral wings of the dorsal raphe nucleus. In order to verify the chemical nature of these cells, the tissue was processed for immunofluorescence with serotonin antibodies. The results obtained showed several triple-labelled cells exhibiting two fluorescent tracers as well as 5-hydroxytryptamine-like immunoreactivity. Some immunonegative tracer-positive cells were also observed, suggesting their nonserotoninergic nature. Finally, electrolytic lesions of the lateral wings of the dorsal raphe nucleus caused a gradual disappearance of serotonin-immunoreactive fibers in these visual areas following different survival times. This correlated well with a decrease in the serotonin content studied by high-pressure liquid chromatography. These results support a role of the serotoninergic dorsal raphe projection to the lateral geniculate body and to the superior colliculus in the processing of visual information, and they suggest that serotonin may have a coordinating influence on primary visual centers.
将辣根过氧化物酶注射到上丘中，标记了中缝背核外侧细胞群中的细胞。这些细胞的细胞结构特征和位置与已知投射到外侧膝状体的细胞表现出显著相似性，因此，测试了中缝背核中可能存在投射到这两个视觉结构的分支神经元。将几种荧光示踪剂——即快蓝、荧光金、碘化丙啶、异硫氰酸罗丹明B和双脒基黄，以不同组合注射到外侧膝状体和上丘中，结果显示中缝背核外侧翼中有单标记和双标记神经元。为了验证这些细胞的化学性质，用血清素抗体对组织进行免疫荧光处理。所得结果显示有几个三重标记细胞，它们表现出两种荧光示踪剂以及5-羟色胺样免疫反应性。还观察到一些免疫阴性的示踪剂阳性细胞，表明它们是非血清素能性质的。最后，对中缝背核外侧翼进行电解损伤，导致在不同存活时间后这些视觉区域中血清素免疫反应性纤维逐渐消失。这与通过高压液相色谱法研究的血清素含量降低密切相关。这些结果支持血清素能中缝背核投射到外侧膝状体和上丘在视觉信息处理中的作用，并且表明血清素可能对初级视觉中枢有协调影响。
