1729
The study was performed in Langendorff isolated perfused guinea - pig hearts by bufadienolides infusion in the absence and presence of verapamil ( 250 , 500ng / ml ) .
 Chemical: bufadienolides; Chemical: verapamil
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: bufadienolides; Chemical: verapamil