Hilscher-Conklin C, Conlon J M, Boyd S K
Department of Biological Sciences, University of Notre Dame, Indiana 46556, USA.
J Comp Neurol. 1998 May 4;394(2):139-51.
The amphibian order Gymnophiona contains more than 150 different species of caecilians. The characterization and distribution of neurohypophysial peptides, however, has not been described for any member of this order. By using high-performance liquid chromatography, radioimmunoassay, and mass spectrometry, we identified the peptide arginine vasotocin (AVT) in brain and pituitary extracts from the caecilian Typhlonectes natans. By using immunocytochemistry, we found five populations of AVT-immunoreactive (AVT-ir) cells in the brain of T. natans. AVT-ir cell bodies were located in the preoptic area, amygdala pars medialis, ventral thalamus, dorsal hypothalamic nucleus, and nucleus of the solitary tract. AVT-ir fibers and terminal fields were widespread. We also identified a mesotocin-like peptide. The distribution of this peptide in the brain of T. natans was more restricted than the distribution of AVT. Mesotocin-like-immunoreactive cell bodies were located almost exclusively in the preoptic area, with only a few other cells located in the amygdala pars medialis. This caecilian species, therefore, possesses neurohypophysial peptides that are similar in their structure and distribution to the peptides found in anuran and urodele amphibian orders.
蚓螈目两栖动物包含150多种不同的蚓螈物种。然而，对于该目任何成员的神经垂体肽的特征和分布尚未有描述。通过使用高效液相色谱、放射免疫分析和质谱分析，我们在南美蚓螈（Typhlonectes natans）的脑和垂体提取物中鉴定出了肽精氨酸血管催产素（AVT）。通过免疫细胞化学方法，我们在南美蚓螈的脑中发现了五群AVT免疫反应性（AVT-ir）细胞。AVT-ir细胞体位于视前区、杏仁核内侧部、腹侧丘脑、下丘脑背核和孤束核。AVT-ir纤维和终末场分布广泛。我们还鉴定出了一种中催产素样肽。该肽在南美蚓螈脑中的分布比AVT的分布更局限。中催产素样免疫反应性细胞体几乎仅位于视前区，仅在杏仁核内侧部有少数其他细胞。因此，这种蚓螈物种拥有的神经垂体肽在结构和分布上与无尾目和有尾目两栖动物中发现的肽相似。
