27885
In vivo we show nuclear localisation of NPAS4 protein in presumptive melatonin target cells of the PT ( alpha GSU - expressing cells ) , while in situ hybridisation studies identified acute and transient expression in the PT of Npas4 in response to melatonin .
 Chemical: melatonin; Chemical: melatonin
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: melatonin