11546
Thus , SN mDA neurons are represented by at least two distinct subpopulations including MPTP - resistant Pitx3 - autonomous , calbindin - positive neurons , and calbindin - negative Pitx - 3 - dependent cells that display elevated vulnerability to toxic injury , and probably correspond to the subpopulation that degenerates in PD .
 Chemical: MPTP
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: MPTP