5699
Furthermore , using an unbiased place conditioning procedure ( CPP ) , intra - PLC D ( 1 ) receptor activation blocks the spontaneous expression of an associative morphine ( 5 mg / kg ; i . p . ) reward memory , while leaving morphine - primed memory expression intact .
 Chemical: morphine; Chemical: morphine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: morphine; Chemical: morphine