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: Physiology
[{'content': 'Action of ANP is? \nSelect and explain. \nA. Bradycardia and hypotension, B. Tachycardia and hypeension, C. Bradycardia and hypeension, D. Tachycardia and hypotension', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The effects of a continuous i.v. infusion of urodilatin at a dose of 30 ng kg-1 min-1 was studied in a patient with congestive hea failure. After 30 min, urodilatin had induced a marked stimulation of plasma cyclic GMP concentrations. In parallel haematocrit increased. No significant diuresis and no change of invasive haemodynamics were observed. After 2 h the patient developed a profuse perspiration. Eighty minutes later he suffered from dizziness due to hypotension (blood pressure 80/40 mmHg) and a sudden bradycardia (50bpm).urodilatin is an ANP.', 'role': 'assistant'}]