Choroid plexus is an additional source of melatonin in the brain

Telma Quintela, Isabel Maria Theriaga Gonçalves, Marco Silva, Ana Catarina Duarte, Paula Guedes, Késsia Andrade, Flávia Freitas, Daniela Talhada, Tânia Albuquerque, Sara Tavares, Luis A. Passarinha, José Cipolla-Neto, Cecília R. A. Santos

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


The cerebrospinal fluid melatonin is released from the pineal gland, directly into the third ventricle, or produced de novo in the brain from extrapineal melatonin sources leading to a melatonin concentration gradient in the cerebrospinal fluid. Despite the interest on this topic, the brain areas capable of producing melatonin are not yet clear. Bearing this in mind, we hypothesized that the choroid plexus (CP) could be one of these melatonin sources. We analyzed and confirmed the presence of the four enzymes required for melatonin synthesis in rat CP and demonstrated that arylalkylamine N-acetyltransferase shows a circadian expression in female and male rat CP. Specifically, this enzyme colocalizes with mitochondria in rat CP epithelial cells, an organelle known to be involved in melatonin function and synthesis. Then, we demonstrated that melatonin is synthesized by porcine CP explants, although without a circadian pattern. In conclusion, our data show that the CP is a local source of melatonin to the central nervous system, probably contributing to its high levels in the cerebrospinal fluid. We believe that in the CP, melatonin might be regulated by its endogenous clock machinery and by the hormonal background.

Original languageEnglish
Article numbere12528
JournalJournal of Pineal Research
Issue number4
Publication statusPublished - 1 Nov 2018


  • arylalkylamine N-acetyltransferase
  • cerebrospinal fluid
  • choroid plexus
  • melatonin
  • mitochondria


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