16069
RATIONALE : Past research has demonstrated that when an animal changes from a previously drug - naive to an opiate - dependent and withdrawn state , morphine ' s motivational effects are switched from a tegmental pedunculopontine nucleus ( TPP ) - dependent to a dopamine - dependent pathway .
 Chemical: morphine; Chemical: dopamine
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: dopamine