Influence of high-dose ketamine on the vascular reactivity of human and porcine isolated coronary artery segments

The influence of ketamine on the vasomotor effect of histamine and serotonin was studied in isolated human and porcine coronary artery rings. Ketamine (10^--³ mol L^-1) attenuated the contractile response to both mediators significantly ( P < 0.05 for histamine concentrations of 310^--⁵ mol L^-1 and above as well as for serotonin concentrations of 310^--⁸ mol L^-1 and above). This effect of ketamine was observed in intact and endothelial denuded porcine rings (difference ns.) as well as in coronary arteries from explanted human hearts of patients undergoing heart transplantation. It is concluded that this reduction of the contractile response to histamine and serotonin caused by ketamine is not dependent on the endothelial function (e.g. endotheliumderived relaxing factor).