4397
Methisergide ( 0 . 5 mg / kg , i . p . ) , a blocker of serotonin receptors , prevented the development of the antinociceptive effect of serotonin .
 GENE: serotonin receptors
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
 Entities: serotonin receptors 
Answer:
 GENE: serotonin receptors