3774
GPR18 was heterologously expressed in rat sympathetic neurons , and the modulation of N - type ( Ca ( v ) 2 . 2 ) calcium channels was examined .
 Chemical: N; Chemical: Ca; Chemical: calcium
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: N; Chemical: Ca; Chemical: calcium