8634
On the other hand , pretreatment with the selective cGMP - preferring phosphodiesterase PDE9 inhibitor BAY 73 - 6691 , increased locomotor activity induced by caffeine , but not paraxanthine .
 Chemical: cGMP; Chemical: BAY 73 - 6691; Chemical: caffeine; Chemical: paraxanthine
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: cGMP; Chemical: BAY 73 - 6691; Chemical: caffeine; Chemical: paraxanthine