30594
All the tested substances exhibited notable synergistic effects with trace amounts of nerve growth factor ( NGF , 1 ng / mL ) or brain - derived neurotrophic factor ( BDNF , 0 . 1 ng / mL ) .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None