Differentiation of the cardiac outflow tract components in alevins of the sturgeon Acipenser naccarii (Osteichthyes, acipenseriformes):: Implications for heart evolution
Differentiation of the cardiac outflow tract components in alevins of the sturgeon Acipenser naccarii (Osteichthyes, acipenseriformes):: Implications for heart evolution
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DOI：
10.1002/jmor.10200
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发表时间：
2004-05-01
影响因子：
1.5
通讯作者：
Sans-Coma, V
中科院分区：
文献类型：
--
作者：
Guerrero, A;Icardo, JM;Sans-Coma, V
先前的研究表明，在成年鲟鱼中，心包内的非心肌节段位于心脏的动脉圆锥和腹主动脉之间。本报告说明了纳卡里鲟鱼这一中间节段的个体发育。研究样本由178只孵化后第1天至24天的绵羊组成。用光学显微镜和电子显微镜对它们进行了检查。我们的观察表明，整个心脏流出道在早期发育过程中表现出心肌特征。在孵化后的第四天到第六天之间，心脏流出道的远端部分经历了一个表型转变，从心肌表型转变为平滑肌样表型。在随后的发育阶段，这一区域相对于整个流出道的长度仅适度增加，变得越来越细胞化。这些细胞很快就会形成一种类似于动脉壁的模式。出生后第7天，弹性蛋白出现在这个部位。因此，两个不同的成分，近端和远端，可以从第四天后在心脏流出道识别纳卡里亚。近端的部分是动脉圆锥，其特点是心肌性质和心内膜垫的存在。远端成分转化为上述心包内的非心肌节段，明确为心脏起源。我们建议将该节段命名为“动脉球”，因为它在形态上等同于硬骨鱼的动脉球。目前的发现和文献数据一起指出，来自心脏神经脊的细胞可能参与了发生在心脏流出道远端的表型转变，导致动脉球的出现。此外，他们还提出，心脏流出道是由脊椎动物进化早期的动脉球和动脉圆锥形成的。最后，我们假设鸟类和哺乳动物的胚胎干与鱼类的动脉球同源。(C)2004年Wiley-Liss公司
Previous work showed that in the adult sturgeon an intrapericardial, nonmyocardial segment is interposed between the conus arteriosus of the heart and the ventral aorta. The present report illustrates the ontogeny of this intermediate segment in Acipenser naccarii. The sample studied consisted of 178 alevins between I and 24 days posthatching. They were examined using light and electron microscopy. Our observations indicate that the entire cardiac outflow tract displays a myocardial character during early development. Between the fourth and sixth days posthatching, the distal portion of the cardiac outflow tract undergoes a phenotypical transition, from a myocardial to a smooth muscle-like phenotype. The length of this region with regard to the whole outflow tract increases only moderately during subsequent developmental stages, becoming more and more cellularized. The cells soon organize into a pattern that resembles that of the arterial wall. Elastin appears at this site by the seventh day posthatching. Therefore, two distinct components, proximal and distal, can be recognized from the fourth day posthatching in the cardiac outflow tract of A. naccarii. The proximal component is the conus arteriosus, characterized by its myocardial nature and the presence of endocardial cushions. The distal component transforms into the intrapericardial, nonmyocardial segment mentioned above, which is unequivocally of cardiac origin. We propose to designate this segment the "bulbus arteriosus" because it is morphogenetically equivalent to the bulbus arteriosus of teleosts. The present findings, together with data from the literature, point to the possibility that cells from the cardiac neural crest are involved in the phenotypical transition that takes place at the distal portion of the cardiac outflow tract, resulting in the appearance of the bulbus arteriosus. Moreover, they suggest that the cardiac outflow tract came to be formed by a bulbus arteriosus and a conus arteriosus from an early period of the vertebrate evolutionary story. Finally, we hypothesize that the embryonic truncus of birds and mammals is homologous to the bulbus arteriosus of fish. (C) 2004 Wiley-Liss, Inc.