7797
In addition , the expression of 5 - HT ( 1A ) mRNA was lower in the hippocampus , 5 - HT ( 1B ) mRNA was higher in the hippocampus and brainstem and SERT mRNA was higher in the brain stem of MRL / MpJ mice .
 Chemical: 5 - HT; Chemical: 5 - HT
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: 5 - HT, 5 - HT 
Answer:
 Chemical: 5 - HT; Chemical: 5 - HT