This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: A.N.S., Subject name: Pharmacology
[{'content': 'Mechanism of action of aminophylline in bronchial asthma: \nSelect and explain. \nA. Decreasing phosphodiesterase activity, B. Direct action on smooth muscles, C. Releasing catecholamines, D. Stabilizing membrane of mast cells', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Aminophylline and other methylxanthines act byInhibiting phosphodiesterase enzyme causing - cAMPBlocking adenosine receptorsReleasing Ca2+ from sarcoplasmic reticulum in cardiac and skeletal muscles.Use-Asthma, COPD, chronic bronchitis', 'role': 'assistant'}]