Influence of the Light Schedule on the Toxicity of Amitriptyline in Chick Embryos

Influence of Hypothyroidism Induced by Thiamazole on the Toxic Interaction between Propranolol and Disopyramide in Chick Embryos

The effect of the hypothyroidism induced by thiamazole on toxic interactions between propranolol and disopyramide were studied in chick embryos. Fertilized eggs of White Leghorns were incubated and investigated. 1.2 mg/0.2 ml/egg of thiamazole was injected into the albumen of fertilized eggs on the 9th day of incubation. The control group was given 0.2 ml/egg of physiological saline in the same manner. Propranolol at 0.1 mg/egg and disopyramide at 0.3 mg/egg were injected into the air sac of fertilized eggs on the 16th day of incubation. Electrocardiograms were recorded 0 to 60 min after the injection. After the injection of propranolol and disopyramide into the thiamazole treated eggs, the heart rate was significantly decreased compared with the thiamazole untreated eggs. These findings indicate that hypothyroidism induced by thiamazole has a marked influence on the toxic interaction between propranolol and disopyramide in chick embryos.