Sommer J R, Johnson E A
J Cell Biol. 1968 Mar;36(3):497-526. doi: 10.1083/jcb.36.3.497.
With light and electron microscopy a comparison has been made of the morphology of ventricular (V) and Purkinje (P) fibers of the hearts of guinea pig, rabbit, cat, dog, goat, and sheep. The criteria, previously established for the rabbit heart, that V fibers are distinguished from P fibers by the respective presence and absence of transverse tubules is shown to be true for all animals studied. No evidence was found of a permanent connection between the sarcoplasmic reticulum and the extracellular space. The sarcoplasmic reticulum (SR) of V fibers formed couplings with the sarcolemma of a transverse tubule (interior coupling) and with the peripheral sarcolemma (peripheral coupling), whereas in P fibers the SR formed only peripheral couplings. The forms of the couplings were identical. The significance, with respect to excitation-contraction coupling, of the difference in the form of the couplings in cardiac versus skeletal muscle is discussed together with the electrophysiological implications of the differing geometries of bundles of P fibers from different animals.
通过光学显微镜和电子显微镜，对豚鼠、兔子、猫、狗、山羊和绵羊心脏的心室（V）纤维和浦肯野（P）纤维的形态进行了比较。先前针对兔心脏确立的标准，即通过横管的有无来区分V纤维和P纤维，在所有研究的动物中都得到了证实。未发现肌浆网与细胞外空间之间存在永久连接的证据。V纤维的肌浆网（SR）与横管的肌膜形成耦合（内部耦合），并与外周肌膜形成耦合（外周耦合），而在P纤维中，SR仅形成外周耦合。耦合的形式是相同的。讨论了心脏与骨骼肌中耦合形式差异在兴奋 - 收缩偶联方面的意义，以及不同动物P纤维束不同几何形状的电生理影响。
