Flohr H, Breull W
Arzneimittelforschung. 1975 Sep;25(9):1400-3.
The distribution of blood flow to the subendocardial, medium and subepicardial layers of the left ventricular free wall was studied in anaesthetized dogs under normoxic (A), hypoxic (B) conditions and under pharmacologically induced (etafenone) coronary vasodilation (C). Regional myocardial blood flow was determined by means of the particle distribution method. In normoxia a transmural gradient of flow was observed, with the subendocardial layers receiving a significantly higher flow rate compared with the subepicardial layers. In hypoxia induced vasodilation this transmural gradient of flow was persistent. In contrast a marked redistribution of regional flow was observed under pharmacologically induced vasodilation. The transmural gradient decreased. In contrast to some findings these experiments demonstrate that a considerable vasodilatory capacity exists in all layers of the myocardium and can be utilized by drugs. The differences observed for the intramural distribution pattern of flow under hypoxia and drug induced vasodilation support the hypothesis that this pattern reflects corresponding gradients of regional myocardial metabolism.
在麻醉犬身上，研究了在常氧（A）、低氧（B）条件下以及在药物诱导（乙胺碘呋酮）的冠状动脉扩张（C）情况下，左心室游离壁的心内膜下、中层和心外膜下层的血流分布。通过颗粒分布法测定局部心肌血流量。在常氧状态下观察到血流的跨壁梯度，与心外膜下层相比，心内膜下层的血流速率显著更高。在低氧诱导的血管扩张时，这种血流的跨壁梯度持续存在。相比之下，在药物诱导的血管扩张时观察到局部血流有明显的重新分布。跨壁梯度减小。与一些研究结果相反，这些实验表明心肌的所有层均存在相当大的血管舒张能力，并且药物可以利用这种能力。在低氧和药物诱导的血管扩张情况下观察到的壁内血流分布模式的差异支持了这样的假说，即这种模式反映了局部心肌代谢的相应梯度。
