Potentiating effects of forskolin on the cardiovascular teratogenicity of ephedrine in chick embryos.

The effects of forskolin on the teratogenicity of ephedrine in the developing chick heart were studied. Forskolin was administered to 4-day chick embryos (Hamburger-Hamilton stage 24) together with ephedrine at doses at which each agent alone caused minimal embryotoxicity. The embryos were examined for malformations on day 14 of incubation. The frequency of malformed embryos exposed to ephedrine (0.5 or 5 mumol) alone was 8 and 26%, respectively, and significantly increased to 47-72% in the presence of 1 nmol forskolin. Forskolin (1 nmol) alone did not induce a significant number of cardiac malformations. These results suggest that the increase in cAMP through stimulation of adenylate cyclase by forskolin is associated with the potentiation of ephedrine-induced cardiovascular malformations in the chick.