You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Mechanism of action of theophylline in bronchial asthma is: and explain in detail?
Ans. (A) Phosphodiesterase 4 inhibition(Ref: Katzung 11th/e p345; KDT 8th/e p245)Theophylline is used in bronchial asthma. Its mechanism of action is:Inhibition of phosphodiesterases particularly PDE-4.Antagonism of adenosine receptors.Enhancement of histone deacetylation. Acetylation of histone is required for activation of inflammatory gene transcription. By inhibiting this process, low-dose theophylline may restore responsiveness to corticosteroids.