[Effect of kynurenine and its metabolites on the vascular effects of serotonin, noradrenaline, and acetylcholine].

In female albino rats anesthetized with urethane, the depressor effect of serotonin was basically diminished by kynurenine, 3-hydroxyanthranilic acid (3-HAA), and anthranilic acid and was potentiated by quinolinic and picolinic acids (PA). All kynurenines were injected in a dose of 200 micrograms. 3-Hydroxykynurenine and nicotinic acid (NA) had a dual action. The pressor effect of noradrenaline was largely diminished by 3-HAA, PA and NA. Each of the rest kynurenines exerted an opposite action in different experiments. The pressor effect of acetylcholine was not affected by kynurenines.