This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
Sodium nitroprusside acts by activation of 
Select and explain. 
A. Guanylate cyclase, B. K+ chanells, C. Ca++ chanells, D. Cyclic AMP
A: Guanylate cyclase
Answer: A: Guanylate cyclase 
Explanation: Nitroprusside generates NO that relaxes the vascular smooth muscle by activating Guanylate cyclase Refer kDT 6/e p548