1724
Receptor binding studies confirmed that UMB24 and ( + / - ) - SM 21 display preferential affinity for sigma2 over sigma1 receptors .
 Chemical: UMB24; Chemical: SM 21
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: UMB24; Chemical: SM 21