The cyclic production of 5-hydroxytryptamine in the opilionid.
D000818:Animals; D002940:Circadian Rhythm; D066298:In Vitro Techniques; D009489:Neurosecretion / Q000502:physiology*; D012701:Serotonin / Q000096:biosynthesis*; D013112:Spiders / Q000378:metabolism*
D012701:Serotonin