The hypothalamic neuropeptides oxytocin (OT) and arginine-vasopressin (AVP) are important factors involved in the control of socio-emotional behaviors via their modulation of amygdala functions. Since anatomical pathways of magnocellular projections to limbic structures in the human brain have not been dissected, we infused ethanol-dissolved tracer DiI into three amygdala nuclei - medial, central and lateral nuclei, and into the mammillary bodies of postmortem fixed human brains. With this modification, lipophilic diffusion of DiI occurred much faster than with conventional DiI crystals. After staining of resliced sections with antibodies against OT or AVP, we detected DiI/OT-positive neurons and their axons, specifically in the supraoptic nucleus (SON), but not in other hypothalamic nuclei producing OT or AVP. DiI fluorescence was found in the lateral portion of the paraventricular nucleus (PVN) and in the fornix columns, together with VP- immunoreactivity, only after DiI injections into the mammillary bodies. Our findings indicate that OT and AVP may have distinct neuronal pathways to the limbic system, and they are different from those previously reported in rodents.

中文翻译：

---

催产素，但不是精氨酸 - 加压素神经元从下丘脑投射到人的杏仁核：死后大脑中基于 DiI 的追踪研究

下丘脑神经肽催产素 (OT) 和精氨酸加压素 (AVP) 是通过调节杏仁核功能参与控制社会情绪行为的重要因素。由于大细胞投射到人脑边缘结构的解剖学途径尚未被解剖，我们将乙醇溶解的示踪剂 DiI 注入三个杏仁核 - 内侧核、中央核和外侧核，并注入死后固定人脑的乳头体。通过这种修改，DiI 的亲脂扩散比传统的 DiI 晶体发生得快得多。在用抗 OT 或 AVP 抗体对重新切片的切片染色后，我们检测到 DiI/OT 阳性神经元及其轴突，特别是在视上核 (SON) 中，但在其他产生 OT 或 AVP 的下丘脑核中未检测到。只有在将 DiI 注射到乳头体后，才能在室旁核 (PVN) 的外侧部分和穹窿柱中发现 DiI 荧光以及 VP 免疫反应性。我们的研究结果表明 OT 和 AVP 可能有不同的神经元通路到边缘系统，它们与之前在啮齿动物中报道的不同。