Masani F
Department of Anatomy, Niigata University School of Medicine, Japan.
J Anat. 1986 Apr;145:133-42.
The myocardial layer of the pulmonary vein of adult rats was examined by electron microscopy. Among ordinary myocardial cells resembling those of the atrial myocardium, clear cells with structural features similar to those of sinus node cells were identified. They were distributed in the intrapulmonary, preterminal portion of the pulmonary vein. They appeared singly or in small groups among the ordinary myocardial cells. Their cytoplasm was characterised by a paucity of myofilaments, irregular disposition of myofilament bundles, small and oval mitochondria, absence of atrial specific granules and a wide cytoplasmic matrix between intracellular organelles. The intercalated discs of node-like cells were composed of small junctional specialisations. Nerve fibres containing small and large vesicles with and without dense cores were juxtaposed to the node-like cells over an intercellular space of more than 200 nm. Taking into consideration physiological data, the possibility is discussed that the node-like cells may have a potential pacemaking activity and represent an ectopic pacemaker centre in the pulmonary vein.
通过电子显微镜检查成年大鼠肺静脉的心肌层。在类似于心房肌心肌细胞的普通心肌细胞中，鉴定出具有与窦房结细胞相似结构特征的透明细胞。它们分布在肺静脉的肺内、终末前部分。它们单个或成小群地出现在普通心肌细胞之间。其细胞质的特征是肌丝稀少、肌丝束排列不规则、线粒体小且呈椭圆形、无心房特异性颗粒以及细胞器之间有宽阔的细胞质基质。结节样细胞的闰盘由小的连接特化组成。含有有致密核心和无致密核心的大小囊泡的神经纤维在超过200nm的细胞间隙与结节样细胞并列。考虑到生理学数据，讨论了结节样细胞可能具有潜在起搏活性并代表肺静脉中的异位起搏中心的可能性。
