左冠状動脈の基始部と中隔枝における血流波形よりみたdipyridamole，nitroglycerinおよびnifedipineの効果

Effects of nitroglycerin, nifedipine and dipyridamole on the left coronary blood flow patterns and the myocardial blood flow in the left ventricle

　nitroglycerinは，古くから狭心症治療薬として用いられており，心筋内の比較的，太い動脈を選択的に拡張させる作用が，その臨床効果の1つの原因ではないかとも考えられている。また，冠状動脈血流量を著明に増加させることで知られているdipyridamoleが，虚血性心疾患に対してあまり効果が期待できないことでも明らかなように，冠状動脈血流量を増加させることが必ずしも虚血性心疾患の治療につながるとは言えないようである。むしろ，血流量よりも，心筋内の血流配分が重要な意味を持つと考えられている。

　そこで，著者らは，nitroglycerin,dipyridamoleそれに，最近，その効果が注目されているnifedipineについて，左冠状動脈の基始部と中隔枝の血流速度波形の変化，ならびに，低酸素吸入のもとにおける効果から，心筋内の血流配分におよぼすこれら薬剤の影響を検討した。

Changes in the blood flow patterns of canine left coronary artery caused by an intravenous administration of nitroglycerin (0.1 mg/kg), nifedipine (5μg/kg) or dipyridamole (0.5 mg/kg) were observed during light morphine anesthesia, and the effects of these drugs on the distribution of the myocardial blood flow were discussed in the paper.

The studies were carried out in three groups. In the first group, consist of 8 canines, the effects of the haemodynamic alterations on the blood flow patterns through the trunk and septal branch of the left coronary artery were observed. In 13 animals of the second group, the changes in theleft coronary blood flow rate and the flow pattern of the left main coronary artery and septal branch due to intravenous administration of nitrogly-cerin, nifedipine or dipyridamole were measured, respectively. The last group, in which 17 cases were included, the experiments were performed under hypoxic circumstances. The dogs were anesthetized with morphine and tranquilizer, and inhaled with mixed gases of 15% oxygen and 85% nitrogen. The parameters observed were the same as did in the second group.