6847
Neither the superoxide radical scavenger , tiron , nor the inhibitor of the dopamine ( DA ) transporter , GBR 12909 , prevented the metabolites ' toxicity .
 superoxide, dopamine, GBR 12909
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 superoxide, dopamine, GBR 12909