12016
The mRNA levels of dopamine receptors , which have functions such as cognition , motor activity , motivation and reward , mood , attention and learning , were significantly down - regulated by TBT exposure .
 Chemical: dopamine; Chemical: TBT
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: dopamine; Chemical: TBT