2701
Acute morphine ( 30mg / kg , s . c . ) treatment significantly attenuated hippocampal LTP and CCK - 8 ( 1ug , i . c . v . ) restored the amplitude of PS that was attenuated by morphine injection .
 Chemical: morphine; Chemical: CCK - 8; Chemical: morphine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: morphine; Chemical: CCK - 8; Chemical: morphine