Abstract
Two kinds of inspiratory gases, 100% O2 and 81% O2+19% CO2, were used for the artificial respiration. Elevating the inspiratory CO2 tension enhanced the decrease in coronary vascular resistance caused by isosorbide dinitrate (100 μg/kg), without any change in heart rate and systemic arterial pressure. Such a change in coronary vascular resistance was prevented by indomethacin. The results suggested an interaction between isosorbide dinitrate and CO2, which was mediated by prostaglandins.
