Helle K B, Miralto A, Pihl K E, Tota B
Cell Tissue Res. 1983;231(2):399-414. doi: 10.1007/BF00222190.
The general and ultrastructural organization of the heart of the elasmobranch, Scyllium stellare, was studied in normal and in anoxic animals. The rich coronary supply was revealed three-dimensionally by the use of corrosion casts, showing a thebesian system of coronary arterioles and capillaries in the thin, outer compact layer as well as in the predominant, inner spongy layer of trabeculae. Only the sinus venosus received a neuronal input of large bundles of granule-containing axons terminating at fenestrated regions of the endocardium and suggesting a neurohormonal function. A simple, tubular sarcoplasmic reticulum with flattened junctional cisternae was present in myocardial cells of 1-5 microns diameter, which contained one or two bundles of myofibrils. The latter were closely apposed to the inner aspect of the plasmalemma. Mitochondria were located centrally in the cells, which were joined by unfolded desmosomes involving Z-band material. Long periods of anoxia were tolerated without loss of heart function, but at the expense of cytoplasmic glycogen. Lipid granules were abundant in all layers and chambers, notably in animals prepared in the summer. The lipid granules displayed a marked increased in electron density when the heart was incubated in a buffered oxalate solution prior to fixation. A glycogen-sparing effect of the lipids during anoxia was observed.
对星鲨（Scyllium stellare）正常及缺氧状态下心脏的大体和超微结构组织进行了研究。通过铸型腐蚀法对丰富的冠状动脉供应进行了三维显示，结果表明，在薄的外层致密层以及主要的内层小梁海绵层中存在冠状动脉小动脉和毛细血管的希氏系统。只有静脉窦接受了大量含颗粒轴突的神经输入，这些轴突终止于心内膜的有窗区域，提示其具有神经激素功能。在直径为1 - 5微米的心肌细胞中存在一种简单的管状肌浆网，其连接池扁平，细胞内含有一或两束肌原纤维。后者紧密贴附于质膜内侧。线粒体位于细胞中央，细胞通过涉及Z带物质的未折叠桥粒相连。心脏能够耐受长时间缺氧而不丧失心脏功能，但代价是细胞质糖原减少。脂质颗粒在所有层和腔室中都很丰富，尤其是在夏季制备的动物中。在固定前将心脏置于缓冲草酸盐溶液中孵育时，脂质颗粒的电子密度显著增加。观察到在缺氧期间脂质对糖原具有节省作用。
