2399
1 - ( 1 - Naphthyl ) piperazine ( 1 - NP ) has been reported to have serotonin antagonist properties at the 5 - HT2 subtype of receptor , and it has been suggested that it may have agonist actions at the 5 - HT1 site .
 5 - HT2 subtype, 5 - HT1 site
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 5 - HT2 subtype, 5 - HT1 site