28493
In MOR mRNA expression study , cotreatment of morphine with mitragynine significantly reduced the down - regulation of MOR mRNA expression as compared to morphine treatment only .
 Chemical: morphine; Chemical: mitragynine; Chemical: morphine
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: morphine, mitragynine, morphine 
Answer:
 Chemical: morphine; Chemical: mitragynine; Chemical: morphine