18623
One hundred and twenty male mice were randomly divided into 6 groups : control , Pb , low - dose verapamil , high - dose verapamil , low - dose nimodipine and high - dose nimodipine ( n = 20 per group ) .
 Chemical: Pb; Chemical: verapamil; Chemical: verapamil; Chemical: nimodipine; Chemical: nimodipine
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: Pb; Chemical: verapamil; Chemical: verapamil; Chemical: nimodipine; Chemical: nimodipine