26087
METHODS : Rats were administered 1 . 0 mg / kg intravenous cocaine and placed into a distinctive environment either immediately or 15 - min after injection , alternating daily with pairings of a second environment with saline .
 cocaine
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 cocaine