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The identification of 5 - HT7 , but not of 5 - HT1 receptors in the rabbit iris , suggests that this population of serotonergic receptors is involved in the relaxation of the sphincter of the pupil .
 Anatomy: iris; Anatomy: sphincter; Anatomy: pupil
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Anatomy 
Text: {0} 
Answer:
 Anatomy: iris; Anatomy: sphincter; Anatomy: pupil