6784
Finally , the development of cross - tolerance to methamphetamine and R - ( - ) - NPA bolsters previous evidence of interplay between CB ( 1 ) and DA D ( 2 ) signaling mechanisms .
 Chemical: methamphetamine; Chemical: R - ( - ) - NPA
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: methamphetamine; Chemical: R - ( - ) - NPA