1082
By contrast , the group II and III mGlu receptor agonists DCG - IV ( 1 mu M ) and l - AP4 ( 3 mu M ) produced an outward current in only 10 - 20 % of PAG neurons tested .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None