[Participation of kynurenine and its derivatives in disorders of the cardiac rhythm].

The influence of tryptophan derivatives: L-kynurenine, 3-hydroxy-DL-kynurenine, kynurenic, xanthurenic, 3-hydroxy-anthranilic and quinolinic acids has been investigated in isolated frog heart. It has been established that L-kynurenine, 3-hydroxy-DL-kynurenine, xanthurenic acid and quinolinic acid at a concentration of 10(-6)-10(-3) mol/l initiate bradycardia. In some cases xanthurenic and quinolinic acids cause a one-minute cardiac arrest in early diastole. 3-hydroxy-anthranilic acid at a concentration of 10(-5) and 5 X 10(-5) mol/l produces premature beats and attacks of tachycardia. In the experiments, using 10(-6)-10(-3) mol/l of kynurenic acid, no impairment of the cardiac rhythm was observed in the isolated frog heart.