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CONCLUSIONS : The discussions focus on the following : ( 1 ) the doses and time - course over which ketamine is associated with damage to , or protection of , neural cells , ( 2 ) how ketamine directs or signals neural cells to undergo apoptosis or necrosis , ( 3 ) how such exposures can trigger mitochondrial dysfunction , ( 4 ) how antioxidants and knockdowns of specific transcription modulators or receptors affect neurotoxicity induced by ketamine , and ( 5 ) whether the potential neural damage can be monitored after ketamine exposure in living animals using positron emission tomography .
 Chemical: ketamine; Chemical: ketamine; Chemical: ketamine; Chemical: ketamine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: ketamine; Chemical: ketamine; Chemical: ketamine; Chemical: ketamine