No evidence for a physiological role of 5-hydroxykynuramine in chicken hemostasis.

Pharmacological effects of 5-hydroxykynuramine (5-HK) were investigated in chicken whole blood. It was shown that 5-HK had a time-depending inhibiting activity on platelet aggregation induced by 5-hydroxytryptamine (5-HT). Experiments were carried out in order to determine whether the inhibitory effect of chicken aorta upon 5-HT-induced aggregation of chicken whole blood could be explained by the formation of 5-HK, a metabolite of 5-HT. Using high performance liquid chromatography (HPLC) in combination with sensitive electrochemical detection, the presence of 5-HK could not be confirmed in chicken blood or aortic tissue, despite the fact that 5-HT levels of chicken blood (6.78 +/- 0.54 micrograms/ml) and aorta (0.69 +/- 0.11 micrograms/g of tissue wet weight) could be determined. These results do not point to a physiological role of 5-HK in chicken whole blood aggregation.