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
Which of the following anesthetic agent may have cerebroprotective affect : 
Select and explain. 
A. Barbiturates, B. Ketamine, C. Etomidate, D. All show cerebroprotective effect
D: All show cerebroprotective effect
Answer: D: All show cerebroprotective effect 
Explanation: CBF ICP CMRO2 Thiopentone ||| ||| ||| Ketamine || || | etomidate ||| ||| | propofol ||| ||| ||| ketamine also has antiemetic effect through NMDA receptor. It also has cerebroprotective effect. JOURNAL : Ketamine is said to increase intracranial pressure (ICP), cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) and hence to be unsuitable for neuroanaesthesia. This may require reconsideration in the light of the neuroprotective propeies mediated by the interaction of ketamine with the N-methyl-D-aspaate receptor (NMDA).