27123
To define the calcium blocker nature of the imidazo [ 2 , 1 - b ] thiazole - 1 , 4 - DHPs and their selectivity on Cav1 . 2 and Cav1 . 3 isoforms we performed binding studies on guinea pig atrial and ventricular membranes , on intact cells expressing the cloned Cav1 . 2a subunit and on rat brain cortex .
 Chemical: calcium; Chemical: imidazo [ 2 , 1 - b ] thiazole - 1 , 4 - DHPs
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: calcium; Chemical: imidazo [ 2 , 1 - b ] thiazole - 1 , 4 - DHPs