Abstract：
It is presumed that the unusual central location of mesencephalic trigeminal neurons is a specialization that allows them to receive synaptic input. However, relatively few synaptic terminals were observed on the somata of mesencephalic trigeminal neurons in macaque monkeys via electron microscopy. This leaves the question of dendritic synaptic terminals open. Unlike the pseudounipolar neurons found in the trigeminal ganglion, some mesencephalic trigeminal neurons have been reported to be multipolar cells exhibiting a number of dendritic processes in non-primate species. To examine whether this morphological feature was also present in macaque monkeys, we retrogradely filled these cells with biotinylated dextran amine by injecting it into the trigeminal nerve entry zone. A portion of the mesencephalic trigeminal neurons exhibited short, poorly branched, dendritic processes. They also exhibited very fine, short processes believed to be somatic spines. Thus, primate trigeminal mesencephalic neurons appear to have specializations aimed at increasing the membrane surface area available for synaptic input.
摘要：
据推测，中脑三叉神经神经元的异常中央位置是一种专业化，使它们能够接收突触输入。然而,通过电子显微镜在猕猴中脑三叉神经神经元的躯体上观察到相对较少的突触末端。这就留下了树突状突触终末的问题。与在三叉神经节中发现的假单极神经元不同，据报道，一些中脑三叉神经神经元是多极细胞，在非灵长类物种中表现出许多树突状过程。为了检查这种形态特征是否也存在于猕猴中，我们通过将生物素化的右旋糖酐胺注射到三叉神经进入区逆行填充这些细胞。部分中脑三叉神经神经元表现出短，分枝差,树突过程。他们也表现得很好，短过程被认为是体细胞刺。因此，灵长类三叉神经中脑神经元似乎具有旨在增加可用于突触输入的膜表面积的专业化。
