3811
The results indicate that rat atrial spontaneous beating is more dependent on [ Na ] o than on [ Ca ] o in a range of + / - 50 % of their normal concentration .
 Chemical: Na; Chemical: Ca
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
 Entities: Na, Ca 
Answer:
 Chemical: Na; Chemical: Ca