16894
The HTR is widely used as a behavioral assay for 5 - HT ( 2A ) activation and to probe for interactions between the 5 - HT ( 2A ) receptor and other transmitter systems .
 Chemical: 5 - HT; Chemical: 5 - HT
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: 5 - HT; Chemical: 5 - HT