6364
Initially , this study confirmed that co - administration of A317491 ( 60 mu g / paw ) , a selective P2X3 receptor antagonist , or pre - treatment with dexamethasone ( 1 mg / mL / kg ) prevents the mechanical hyperalgesia induced by carrageenan ( 300 mu g / paw ) in the rat ' s hind paw .
 Chemical: A317491; Chemical: dexamethasone
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: A317491; Chemical: dexamethasone