4768
However , methylphenidate is a dopamine agonist via the inhibition of uptake of dopamine , and therefore dopaminergic systems in the brainstem ( mainly the midbrain ) and the spinal cord were unlikely to participate in the onset of this syndrome .
 Chemical: methylphenidate; Chemical: dopamine; Chemical: dopamine
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: methylphenidate; Chemical: dopamine; Chemical: dopamine