Paes de Almeida O, Bohm C M, de Paula Carvalho M, Paes de Carvalho A
J Morphol. 1975 Apr;145(4):409-33. doi: 10.1002/jmor.1051450403.
The pulmonary veins of albino Wistar rats were studied by means of light and electron microscopy. The media of larger veins consists of cardiac muscle fibers which extend until the vessels attain about 100 mu in diameter. This coat consists of external longitudinal fibers and internal circular fibers. The vasa vasorum are well developed and the capillaries show pseudofenestrations. The numerous adrenergic and cholinergic nerve endings do not form typical motor end-plates as seen in skeletal muscles. The ultrastructure of these media muscle fibers is similar to that of the rat hearts. The smooth muscle layer of larger pulmonary veins is not continuous as it is in smaller veins where it forms cushions. Comparison of albino rats and other rodents reveal striking differences. Action potential shape and propagation velocity (0.5-1.2 m/s) along the myocardial coat of the pulmonary vein were similar to those observed in the left atrium and so was their sensitivity to locally applied acetylcholine. The physiological direction of propagation in rat pulmonary veins is toward the lung. This fingind lends support to the hypothesis of a rhythmic, valve-like action of the striated musculature of the pulmonary venous wall during the systole and a possible role in the capacitance of the pulmonary circulation.
采用光镜和电镜对白化Wistar大鼠的肺静脉进行了研究。较大静脉的中膜由心肌纤维组成，这些纤维一直延伸到血管直径达到约100微米。该层由外部纵向纤维和内部环形纤维组成。血管滋养管发育良好，毛细血管可见假窗孔。众多的肾上腺素能和胆碱能神经末梢不像在骨骼肌中那样形成典型的运动终板。这些中膜肌纤维的超微结构与大鼠心脏的相似。较大肺静脉的平滑肌层不像较小静脉那样连续，较小静脉的平滑肌层形成垫状结构。白化大鼠与其他啮齿动物的比较显示出显著差异。沿肺静脉心肌层的动作电位形状和传播速度（0.5 - 1.2米/秒）与左心房观察到的相似，它们对局部应用乙酰胆碱的敏感性也相似。大鼠肺静脉的生理传播方向是朝向肺部。这一发现支持了关于肺静脉壁横纹肌在收缩期具有节律性、瓣膜样作用以及在肺循环容量方面可能发挥作用的假说。
