Kolesová Hana, Lametschwandtner Alois, Rocek Zbynek
Institute of Anatomy, First Faculty of Medicine, Charles University, Prague, Czech Republic.
J Anat. 2007 Apr;210(4):379-93. doi: 10.1111/j.1469-7580.2007.00710.x. Epub 2007 Mar 16.
In order to gain insights into how the aortic arches changed during the transition of vertebrates to land, transformations of the aortic arches during the metamorphosis of Pelobates fuscus were investigated and compared with data from the early development of a recent ganoid fish Amia calva and a primitive caudate amphibian Salamandrella keyserlingi. Although in larval Pelobates, as in other non-pipid anurans, the gill arches serve partly as a filter-feeding device, their aortic arches maintain the original piscine-like arrangement, except for the mandibular and hyoid aortic arches which were lost. As important pre-adaptations for breathing of atmospheric oxygen occur in larval Pelobates (which have well-developed, though non-respiratory lungs and pulmonary artery), transformation of aortic arches during metamorphosis is fast. The transformation involves disappearance of the ductus Botalli, which results in a complete shunting of blood into the lungs and skin, disappearance of the ductus caroticus, which results in shunting of blood into the head through the arteria carotis interna, and disappearance of arch V, which results in shunting blood to the body through arch IV (systemic arch). It is supposed that the branching pattern of the aortic arches of permanently water-dwelling piscine ancestors, of intermediate forms which occasionally left the water and of primitive tetrapods capable of spending longer periods of time on land had been the same as in the prematamorphic anuran larvae or in some metamorphosed caudates in which the ductus caroticus and ductus Botalli were not interrupted, and arch V was still complete.
为了深入了解在脊椎动物向陆地过渡期间主动脉弓是如何变化的，对黄斑蟾变态过程中主动脉弓的转变进行了研究，并与近期的硬鳞鱼雀鳝和原始有尾两栖动物东北小鲵早期发育的数据进行了比较。尽管在黄斑蟾幼虫中，与其他非姬蛙科无尾目动物一样，鳃弓部分用作滤食装置，但它们的主动脉弓保持了原始的鱼类样排列，除了失去的下颌主动脉弓和舌主动脉弓。由于在黄斑蟾幼虫中出现了对大气氧呼吸的重要预适应（其具有发育良好但非呼吸性的肺和肺动脉），变态期间主动脉弓的转变很快。这种转变包括动脉导管的消失，这导致血液完全分流到肺和皮肤；颈动脉导管的消失，这导致血液通过颈内动脉分流到头部；以及第五弓的消失，这导致血液通过第四弓（体动脉弓）分流到身体。据推测，永久生活在水中的鱼类祖先、偶尔离开水的中间形式以及能够在陆地上停留更长时间的原始四足动物的主动脉弓分支模式与变态前的无尾目幼虫或某些变态后的有尾两栖动物相同，在这些动物中，颈动脉导管和动脉导管没有中断，第五弓仍然完整。
