Breisch E A, White F, Jones H M, Laurs R M
Cell Tissue Res. 1983;233(2):427-38. doi: 10.1007/BF00238308.
The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4-6 microns diameter) than the spongy layer (2.5-5 microns diameter). Ultrastructurally the myocardium displays normal arrangements of myofibrils and mitochondria. The sarcoplasmic reticulum is poorly developed. The intercalated discs are simple with the fascia adherens being the most frequent junctional type observed; occasionally a desmosome was seen. Nexus type junctions are present but are unassociated with the intercalated discs. There are no t-tubules evident but the plasmalemma exhibits numerous caveolae which rarely form couplings with the sarcoplasmic reticulum. A morphometric analysis of the volume percent of mitochondria and myofibrils showed that the myocardial cells in the spongy layer of the heart have a significantly greater volume percentage of mitochondria than the compact layer. No significant differences were found between myocardial regions when the volume percentages of myofibrils were compared. The physiological studies revealed that the albacore tuna has heart rates (120 bpm) and ventricular blood pressures (100 mmHg) that are among the highest reported for fish.
对长鳍金枪鱼心脏的共同心室进行了研究。心室心肌由外层致密层和较厚的内层海绵层组成。致密层的细胞（直径4 - 6微米）比海绵层的细胞（直径2.5 - 5微米）略大。超微结构上，心肌显示出肌原纤维和线粒体的正常排列。肌浆网发育不良。闰盘简单，粘着小带是观察到的最常见连接类型；偶尔可见桥粒。缝隙连接存在，但与闰盘无关。未见明显的横小管，但质膜上有大量小窝，很少与肌浆网形成偶联。对线粒体和肌原纤维体积百分比进行的形态计量分析表明，心脏海绵层的心肌细胞中线粒体的体积百分比明显高于致密层。比较肌原纤维体积百分比时，心肌区域之间未发现显著差异。生理学研究表明长鳍金枪鱼的心率（120次/分钟）和心室血压（100毫米汞柱）在鱼类中是报道的最高值之一。
