11148
Acute tolerance to analgesia ( p < 0 . 01 ) and effects on respiratory frequency ( p < 0 . 05 ) was observed in mice pre - treated with 100 mg / kg morphine in comparison to saline .
 Chemical: morphine
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: morphine