3685
Serotonin transporter ( SERT ) immunoreactivity and SERT radioligand binding were comparable between age groups in all three brain regions .
 Chemical: Serotonin
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: Serotonin