10990
Among them , the cardiac M ( 3 ) muscarinic acetylcholine receptor ( M ( 3 ) - mAChR ) has been studied for more than 2 decades since its first discovery in mammalian heart in 1990s .
 Chemical: acetylcholine
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: acetylcholine