10921
Histamine transiently increased cAMP and c-fos expression through H2 receptors .
 c-fos, H2 receptors
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 c-fos, H2 receptors