This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intravenous Anesthetic Agents, Subject name: Anaesthesia
[{'content': 'Which of the following intravenous anaesthetic agent causes decrease in postoperative nausea and vomiting : \nSelect and explain. \nA. Propofol, B. Thiopentone, C. Etomidate, D. Ketamine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Propofol is known to posses direct antiemetic effects. However its mechanism of action in this context still not well understood. The possible effects of Propofol on the cerebral coex, its interactions with the dopaminergic and serotonergic systems.', 'role': 'assistant'}]