11523
Morphine pharmacology in beta - arrestin - 2 knockout mice suggested that a ligand that promotes coupling of the mu - opioid receptor ( MOR ) to G proteins , but not beta - arrestins , would result in higher analgesic efficacy , less gastrointestinal dysfunction , and less respiratory suppression than morphine .
 Chemical: Morphine; 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, morphine 
Answer:
 Chemical: Morphine; Chemical: morphine