Arrechedera H, Strauss M, Argüello C, Ayesta C, Anselmi G
J Mol Cell Cardiol. 1984 Oct;16(10):885-95. doi: 10.1016/s0022-2828(84)80025-5.
In the early stages of chick embryo development (days 3-5) the myocardium of the atrio-ventricular canal (AV) is continuous with the atrial and ventricular muscles; however, interruption of muscular continuity is observed at later stages (from day 6 to day 8). The most relevant event occurring at the AV canal region is the dissociation of the myocytes due to the loss of their cellular attachments, rather than an invasion of connective tissue cells (endocardial and sub-epicardial) located on both sides of the myocardium. In this study, particular attention was paid to the sequential changes that take place in the myocardium of this region, these being (1) a reduction in the number of desmosomes and intercalated discs with the subsequent appearance of large, inter-cellular spaces between myocytes; (2) migration of these cells through a complex extra-cellular matrix, to which it appears to be closely related, suggesting that the macromolecules of this matrix may be being synthesized by the myocytes, and may take part in the process of cardiac cell separation; (3) incorporation of the myocytes in the developing tricuspid valve, where they co-exist with fibroblasts. The results of the study correspond remarkably well to those previously carried out on the left AV canal myocardium, suggesting that the behaviour of the muscle is the same, at all points around the AV canal.
在鸡胚发育的早期阶段（第3 - 5天），房室管（AV）的心肌与心房和心室肌相连；然而，在后期阶段（从第6天到第8天）观察到肌肉连续性中断。在房室管区域发生的最相关事件是心肌细胞由于细胞连接丧失而解离，而非心肌两侧的结缔组织细胞（心内膜和心外膜下细胞）的侵入。在本研究中，特别关注了该区域心肌中发生的一系列变化，这些变化包括：（1）桥粒和闰盘数量减少，随后心肌细胞之间出现大的细胞间隙；（2）这些细胞通过与之似乎密切相关的复杂细胞外基质迁移，这表明该基质的大分子可能由心肌细胞合成，并可能参与心脏细胞分离过程；（3）心肌细胞并入正在发育的三尖瓣，在那里它们与成纤维细胞共存。该研究结果与先前对左房室管心肌进行的研究结果非常吻合，表明在房室管周围所有点上肌肉的行为都是相同的。
