8903
The affinity of these new compounds for chicken brain melatonin receptors and recombinant human MT ( 1 ) and MT ( 2 ) receptors was evaluated using 2 - [ ( 125 ) I ] - iodomelatonin as radioligand .
 Chemical: melatonin; Chemical: 2 - [ ( 125 ) I ] - iodomelatonin
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: melatonin; Chemical: 2 - [ ( 125 ) I ] - iodomelatonin