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': 'All of the following acts on GABA receptor except:- \nSelect and explain. \nA. Thiopentone, B. Propofol, C. Zolpidem, D. Ketamine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ketamine acts on NMDA receptor. Xenon and nitrous oxide also acts on NMDA receptor. Rest other intravenous and inhalational agents act on GABA receptor.', 'role': 'assistant'}]