This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following enzyme is inhibited by Aminophylline ? 
Select and explain. 
A. Monoamine oxidase, B. Alcohol dehydrogenase, C. Cytochrome P-450, D. Phosphodiesterase
D: Phosphodiesterase
Answer: D: Phosphodiesterase 
Explanation: Theophylline is a non selective phosphodiesterase inhibitor. Inhibition of this enzyme cause elevation of cellular cAMP and cGMP and cause bronchodilation. Other mechanism of action of Aminophylline includes: Antagonises adenosine receptor Increase release of IL 10 which has anti inflammatory effect It prevents the translocation of the pro-inflammatory transcription factor NF-kB into the nucleus, potentially reducing the expression of inflammatory genes in asthma and COPD. Side effects: Headache Nausea Vomiting Abdominal discomfo Restlessness Increased acid secretion Diuresis At high concentration it cause cardiac arrhythmias Very high concentration causes seizures Ref: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e chapter 36.