Beal J A, Bice T N
Department of Cellular Biology and Anatomy, Louisiana State University Medical Center, Shreveport 71130-3932.
Brain Res Dev Brain Res. 1994 Mar 18;78(1):49-56. doi: 10.1016/0165-3806(94)90008-6.
The temporal and spatial neurogenic patterns of spinothalamic and spinocerebellar neurons were determined in spinal cord segment L1 of the rat. Neurogenic patterns were demonstrated with [3H]thymidine administered to fetal rats during the period when neurons with supraspinal projections are known to be generated, i.e. on one of embryonic (E) days E13, E14, or E15. The animals were allowed to survive 50 to 100 days postpartum, then neurons with spinothalamic and spinocerebellar projections were retrogradely filled with fluorescent axonal tracers, Fluoro-Gold or True blue, which were pressure injected into the dorsal thalamus and cerebellum in various combinations in the same and in separate animals. Neurons labeled with each retrograde tracer and [3H]thymidine and neurons labeled with retrograde tracers alone were counted in spinal cord segment L1 in each of the animals. Spinothalamic and spinocerebellar neurons were found to be separate and distinct populations. Statistical analysis of the data showed that spinothalamic and spinocerebellar neurons also have distinctly different patterns of neurogenesis which suggest early determination in each cell line. The temporal neurogenic pattern followed a projection-distance gradient, such that spinothalamic neurons, which have longer axons than spinocerebellar neurons, completed neurogenesis prior to spinocerebellar neurons in each region of the spinal gray.
在大鼠脊髓L1节段确定了脊髓丘脑束和脊髓小脑束神经元的时空神经发生模式。在已知具有脊髓上投射的神经元产生的时期，即胚胎（E）期的E13、E14或E15中的一天，给胎鼠注射[³H]胸腺嘧啶核苷来显示神经发生模式。让动物在产后存活50至100天，然后用荧光轴突示踪剂（氟金或真蓝）逆行标记具有脊髓丘脑束和脊髓小脑束投射的神经元，这些示踪剂以不同组合通过压力注射到同一动物和不同动物的背侧丘脑和小脑中。在每只动物的脊髓L1节段中，对用每种逆行示踪剂和[³H]胸腺嘧啶核苷标记的神经元以及仅用逆行示踪剂标记的神经元进行计数。发现脊髓丘脑束和脊髓小脑束神经元是不同的群体。对数据的统计分析表明，脊髓丘脑束和脊髓小脑束神经元也具有明显不同的神经发生模式，这表明每个细胞系早期就已确定。时间神经发生模式遵循投射距离梯度分布，即与脊髓小脑束神经元相比轴突更长的脊髓丘脑束神经元，在脊髓灰质的每个区域中比脊髓小脑束神经元更早完成神经发生。
