2810
Rats , tolerant to ketamine - dominant combinations , were cross - tolerant to both drugs , while those tolerant to morphine - dominant combinations were cross - tolerant to morphine but showed either no cross - tolerance or an augmented response to ketamine .
 Chemical: ketamine; Chemical: morphine; Chemical: morphine; Chemical: ketamine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: ketamine; Chemical: morphine; Chemical: morphine; Chemical: ketamine