Abstract
The present investigation was conducted to explore the effects of ACTH on the relaxation of guinea pig trachea with various bronchodilators.
1) It was shown that ACTH by itself was a very weak bronchodilator, and that ACTH did not show any relaxation of GPT at the dose of 100ng/ml, 500ng/ml and 1μg/ml.
2) Bronchodilating effects of Isop., Hexop., Salb. and Adr. were markedly potentiated with continuous infusion of ACTH (10ng/ml).
3) Bronchodilating effect of Isop. (5ng/ml) was potentiated, dose-dependently, by ACTH.
4) Bronchodilating effects of PGE2 and Aminoph, were not potentiated with continuous infusion of ACTH.
5) These results suggest that ACTH has a direct effect on GPT by potentiating the bronchodilating effects with various β-stimulators.
