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
[{'content': 'The mechanism of action of sodium nitroprusside is? \nSelect and explain. \nA. Increased cAMP, B. Increased guanylate cyclase, C. Calcium channel blockage, D. IC channel opener', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \'b\' i.e., Increases Guanyl Cyclase o "Nitroprusside dilates both aerial and venous vessels, resulting in reduced peripheral vascular resistance and venous return. The action occurs as a result of activation of guanylyl cyclase, either release of nitric oxide or by direct stimulation of enzyme. The result is increased intracellular cGMP, which relaxes vascular smooth muscle".', 'role': 'assistant'}]