2070
The effect appears to be mediated by central nicotine receptors , possibly located on dopaminergic neurons , and also requires the activation of both D1 and D2 dopamine receptors .
 Chemical: nicotine; Chemical: dopamine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
 Entities: nicotine, dopamine 
Answer:
 Chemical: nicotine; Chemical: dopamine