Johnston R N, Shaw C, Brennan G P, Maule A G, Halton D W
Comparative Neuroendocrinology Research Group, School of Clinical Medicine, Queen's University of Belfast, Northern Ireland.
J Comp Neurol. 1995 Jun 19;357(1):76-84. doi: 10.1002/cne.903570108.
Over the past decade it has become clear that the nervous systems of platyhelminths are both complex and highly developed, particularly in peptidergic elements. The central position of an ancestral flatworm in the evolution of the Bilateria has placed a greater importance on the study of modern flatworms. Using antisera generated to the C-terminal region of platyhelminth neuropeptide F and the molluscan neuropeptide, FMRFamide, in immunocytochemistry at both light and ultrastructural levels, immunoreactivities have been localised within the nervous systems of three species of triclad turbellarians, Dugesia lugubris, Dendrocoelum lacteum, and Polycelis nigra, and one species of monogenean trematode, Diclidophora merlangi. Extensive immunostaining was obtained with both antisera throughout the central and peripheral nervous systems of all species studied, but intensity and abundance was significantly greater in the turbellarians. Indirect electron-immunogold labeling demonstrated that immunoreactivity to both neuropeptides was often colocalised in neurosecretory vesicles, although discrete populations of vesicles were also observed. Radioimmunoassay of extracts of all species confirmed that neuropeptide F immunoreactivity was consistently more abundant than FMRFamide immunoreactivity, and that the levels of both in the three turbellarians were several orders of magnitude greater than those found in the monogenean. Chromatographic analyses of turbellarian extracts revealed that neuropeptide F and FMRFamide immunoreactivities were attributable to different peptides. These data imply that the neuropeptidergic systems systems of turbellarians are considerably more extensive than those of monogeneans, and would suggest that a regression has occurred in the latter as a consequence of the adoption of a mere sedentary parasitic lifestyle.
在过去十年中，很明显扁形虫的神经系统既复杂又高度发达，尤其是在肽能元件方面。原始扁虫在两侧对称动物进化中的核心地位使得对现代扁虫的研究变得更加重要。利用针对扁形虫神经肽F的C末端区域和软体动物神经肽FMRF酰胺产生的抗血清，在光镜和超微结构水平的免疫细胞化学研究中，免疫反应性已定位在三种三肠目涡虫（阴暗真涡虫、乳突树涡虫和黑点多盘涡虫）以及一种单殖吸虫（黑线双盘吸虫）的神经系统内。在所研究的所有物种的中枢和外周神经系统中，两种抗血清均获得了广泛的免疫染色，但在涡虫中的强度和丰度明显更高。间接电子免疫金标记表明，对两种神经肽的免疫反应性常常共定位于神经分泌小泡中，尽管也观察到了离散的小泡群体。对所有物种提取物的放射免疫分析证实，神经肽F的免疫反应性始终比FMRF酰胺的免疫反应性更丰富，并且三种涡虫中两者的水平比单殖吸虫中的水平高几个数量级。对涡虫提取物的色谱分析表明，神经肽F和FMRF酰胺的免疫反应性归因于不同的肽。这些数据表明，涡虫的肽能系统比单殖吸虫的肽能系统要广泛得多，这表明单殖吸虫由于仅仅采用了固定的寄生生活方式而发生了退化。
