title: Serotonin nerve endings and regulation of pupillary diameter.
abstract: On the basis of the effects caused by 5-6-dihydroxytryptamine (5-6-DHT) on the serotonin nerve endings (chronic degeneration with depletion of the mediator), the eventual existence of serotoninergic fiber regulating pupillary diameter (PD) and intraocular pressure (IOP) was studied from a functional point of view. For the miotic effect found after administration of 5-6-DHT in rabbit, not accompanied by any change in the IOP, the hypothesis of a coparticipation of the serotoninergic fibers in the regulation of the PD is proposed, thus sustaining the concept that both PD and IOP respond to mechanisms of autonomous control. A phenomenon of receptorial supersensitivity to serotonin after the lesion of the nerve endings, dependent on 5-6-DHT, was also encountered.
mesh_terms: D015115:5,6-Dihydroxytryptamine / Q000494:pharmacology*; D000818:Animals; D005260:Female; D007275:Injections, Intravenous; D007429:Intraocular Pressure / Q000187:drug effects; D007498:Iris / Q000294:innervation; D008297:Male; D008916:Miotics / Q000494:pharmacology; D011680:Pupil / Q000187:drug effects*; D011817:Rabbits; D011985:Receptors, Serotonin / Q000187:drug effects*
chemical_list: D008916:Miotics; D011985:Receptors, Serotonin; D015115:5,6-Dihydroxytryptamine