5615
Interestingly , the degree of additional lever - presses negatively correlated with serotonin - transporter binding in the prefrontal cortex , even in saline - pretreated controls .
 Chemical: serotonin
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: serotonin 
Answer:
 Chemical: serotonin