EXPERIMENTAL INDUCTION OF CARDIOVASCULAR MALFORMATIONS IN THE CHICK-EMBRYO

Experimental induction of cardiovascular malformations in the chick embryo can be successfully accomplished by beta-adrenergic receptor stimulants and methylxanthines. Beta-1 receptor activity plays an important role in the teratogenic process. Isoproterenol is the most potent beta receptor stimulant and is associated with the greater teratogenic effect. Pretreatment with beta receptor blocking agents significantly reduce the incidence of malformations. Synergism of sympathomimetic agent with cocaine has been shown. Cardivascular malformations can be related to alterations in hemodynamic function as shown by a decrease in end-diastolic and end-systolic volumes, stroke volume, and cardiac output and a rapid and sustained increase in ejection fraction. Finally, the exposure to high concentration of calcium chloride solution (100 mM) increased considerably the incidence of cardiovascular malformations.