Martinez-Palomo A, Alanis J, Benitez D
J Cell Biol. 1970 Oct;47(1):1-17. doi: 10.1083/jcb.47.1.1.
Cardiac cells with distinctive electrophysiological and morphological features were found at the junctional region between Purkinje and ventricular cells of the dog heart. The electrophysiological exploration of these "transitional" cells revealed action potentials markedly different in configuration from those generated by Purkinje or by ventricular cells. The impaled cardiac cells which generated transitional action potentials were identified in serial sections and studied with the light and the electron microscopes. The transitional cells were found to be characterized cytologically by: (a) their subendocardial location, (b) their small diameter, (c) the absence of T system and sarcoplasmic reticulum, and (d) the lack of intercalated discs under the light microscope and the sparsity of specialized intercellular junctions under the electron microscope. Purkinje, transitional, and ventricular cells were found to be joined by gap junctions permeable to lanthanum. A quantitative difference in the extent and distribution of specialized intercellular junctions may be one of the factors responsible for the slow velocity of conduction characteristic of the Purkinje-ventricular junctional region.
在犬心脏的浦肯野细胞与心室细胞的交界区域发现了具有独特电生理和形态特征的心脏细胞。对这些“过渡”细胞的电生理研究显示，其动作电位的形态与浦肯野细胞或心室细胞产生的动作电位明显不同。在连续切片中识别出产生过渡性动作电位的刺入心脏细胞，并通过光学显微镜和电子显微镜进行研究。发现过渡细胞在细胞学上具有以下特征：（a）它们位于心内膜下，（b）直径较小，（c）缺乏T系统和肌浆网，（d）在光学显微镜下没有闰盘，在电子显微镜下特殊细胞间连接稀疏。发现浦肯野细胞、过渡细胞和心室细胞通过对镧可通透的缝隙连接相连。特殊细胞间连接的范围和分布的定量差异可能是导致浦肯野 - 心室交界区域传导速度缓慢的因素之一。
