The pyridoindole derivative (DH 1011), a new antiarrhythmic agent, and quinidine were examined for teratogenic and embryotoxic activity in chick embryos. The tested substance was injected into egg albumen on incubation days 5, 6 or 7 in doses of 0.4, 0.8 or 1.6 mg per egg. All embryos were examined on day 19. A significantly decreased survival rate of embryos was recorded only after the dose of 1.6 mg DH 1011 per egg administered on incubation day 5. Correlation between body and heart weight was found in all surviving embryos after administration of each agent on incubation days 5 and 6. Chondrodystrophy was the major deformity in chick embryos treated on incubation day 5. The results of this investigation suggest that neither quinidine nor DH 1011 have adverse effects on the late embryonal development of chickens.

Centre of Physiological Sciences Slovak Academy of Sciences Bratislava Czechoslovakia