29448
METHODS : Resident animals were intracerebroventricularly ( icv ) administered with different doses of synthetic oxytocin and oxytocin receptor antagonist , alone and in combination , in order to manipulate brain oxytocin functioning and to assess their behavioral response to an intruder .
 oxytocin, oxytocin, oxytocin
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 oxytocin, oxytocin, oxytocin