Hemodynamic effects of endothelin in anesthetized dogs

: The purpose of the present study was to investigate and compare the hemodynamic responses that can be elicited in anesthetized dogs by intravenous administration of endothelin at rates of 300 (group E-I, n = 9) and 600 pmol.kg-1 (group E-II, n = 9) for 15 minutes. In group E-I, no significant pressure response was observed after administration of endothelin and cardiac index remained unchanged throughout the experiment. However, right and left ventricular work indices increased significantly but left ventricular maximum dp/dt and pulmonary vascular resistance decreased significantly. In group E-II, mean arterial pressure increased significantly by elevating systemic vascular resistance with marked decrease in cardiac index. However, right and left ventricular work indices remained unchanged throughout the experiment. On the other hand, each dose of endothelin significantly increased pulmonary capillary wedge pressure and left ventricular end-diastolic pressure but decreased heart rate. The present data revealed that the hemodynamic effects were different according to the doses of endothelin infused. In conclusion, our results show that endothelin (600 pmol.kg-1 BW) produces a long lasting increase in arterial pressure and endothelin-induced pressure responses are caused by an elevation in systemic vascular resistance.