21667
CONCLUSIONS : Our results indicate that hippocampal synaptic depression is involved in ketamine - induced memory impairment , and this is modulated by D1 / D5 receptors activation and AMPA receptors endocytosis .
 ketamine, AMPA
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 ketamine, AMPA