Cestodes are common gastrointestinal parasites of humans and livestock. They attach to the host gut and, without a mouth or intestinal system, absorb nutrients through their epidermis. Here we show that despite this simplified anatomy and sessile lifestyle, they maintain a complex neuromuscular system. We used fluorescently labelled phalloidin as a specific probe for filamentous actin to define the overall organisation of several distinct muscle systems in the cyclophyllidean Moniezia expansa. Like all flatworms, the body wall musculature below the neodermis of this intestinal parasite of sheep is characterised by outer circular and inner longitudinal muscle fibres. Diagonal fibres, typically found in free-living and trematode platyhelminths, on the other hand, are notably absent. Prominent longitudinal sheaths dominate the parenchyma and provide retractor muscles to the four acetabula in the scolex; they attach at the bottom of each cup-shaped holdfast. Within sexually mature proglottids, circular fibres dominate the duct walls of the male and female reproductive systems. Nerve cells and fibres that express serotonin or neuropeptide F supply well-developed innervation to several of the described muscle systems: emanating from the central nervous system, fibres in the periphery develop pervasive nerve nets that anastomose within body wall musculature as well as the parenchymal longitudinal and oblique muscle fibres, and innervate the sexual organs and gonopore in mature proglottids. Using homology searches, we provide evidence for 20 neuropeptide precursors together with four prepropeptide processing enzymes as well as several 5-HT signalling components to be represented in the Moniezia transcriptome.

绦虫是人类和牲畜常见的胃肠道寄生虫。它们附着在宿主肠道上，没有口腔或肠道系统，通过表皮吸收营养。在这里，我们表明，尽管有这种简化的解剖结构和固着的生活方式，但它们仍然保持着复杂的神经肌肉系统。我们使用荧光标记的鬼笔环肽作为丝状肌动蛋白的特异性探针来定义环叶莫尼齐亚扩张中几个不同肌肉系统的整体组织。与所有扁虫一样，这种羊肠道寄生虫的新真皮下方的体壁肌肉组织的特征是外部圆形和内部纵向肌纤维。另一方面，通常在自由生活的扁形动物和吸虫扁形动物中发现的对角纤维却明显缺失。突出的纵向鞘支配实质，并为头节的四个髋臼提供牵缩肌；它们固定在每个杯形固定器的底部。在性成熟的节片中，圆形纤维主导着雄性和雌性生殖系统的导管壁。表达血清素或神经肽 F 的神经细胞和纤维为所述的几个肌肉系统提供发育良好的神经支配：从中枢神经系统发出，周围的纤维发育出普遍的神经网，在体壁肌肉组织以及实质纵向上吻合和斜肌纤维，并支配成熟节片中的性器官和性孔。通过同源性搜索，我们提供了莫尼齐亚转录组中 20 种神经肽前体以及四种前肽加工酶以及几种 5-HT 信号传导成分的证据。