20525
In the present study , we report that ethanol significantly and dose - dependently reduced the antinociceptive tolerance produced by morphine and the cross tolerance between DAMGO and morphine in the mouse tail - flick test .
 Chemical: ethanol; Chemical: morphine; Chemical: DAMGO; 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: ethanol; Chemical: morphine; Chemical: DAMGO; Chemical: morphine