Comparative analysis of monoaminergic cerebrospinal fluid-contacting cells in Osteichthyes (bony vertebrates).
Cerebrospinal fluid-contacting (CSF-c) cells containing monoamines such as dopamine (DA) and serotonin (5-HT) occur in the periventricular zones of the hypothalamic region of most vertebrates except for placental mammals. Here we compare the organization of the CSF-c cells in chicken, Xenopus, and zebrafish, by analyzing the expression of synthetic enzymes of DA and 5-HT, respectively, tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), and draw an evolutionary scenario for this cell population. Due to the lack of TH immunoreactivity in this region, the hypothalamic CSF-c cells have been thought to take up DA from the ventricle instead of synthesizing it. We demonstrate that a second TH gene (TH2) is expressed in the CSF-c cells of all the three species, suggesting that these cells do indeed synthetize DA. Furthermore, we found that many CSF-c cells coexpress TH2 and TPH1 and contain both DA and 5-HT, a dual neurotransmitter phenotype hitherto undescribed in the brain of any vertebrate. The similarities of CSF-c cells in chicken, Xenopus, and zebrafish suggest that these characteristics are inherited from the common ancestor of the Osteichthyes. A significant difference between tetrapods and teleosts is that teleosts possess an additional CSF-c cell population around the posterior recess (PR) that has emerged in specific groups of Actinopterygii. Our comparative analysis reveals that the hypothalamus in mammals and teleosts has evolved in a divergent manner: placental mammals have lost the monoaminergic CSF-c cells, while teleosts have increased their relative number.
['Xavier|Anna L|AL|', 'Fontaine|Romain|R|', 'Bloch|Solal|S|', 'Affaticati|Pierre|P|', 'Jenett|Arnim|A|', 'Demarque|Michaël|M|', 'Vernier|Philippe|P|', 'Yamamoto|Kei|K|http://orcid.org/0000-0002-8775-9022']
D000818:Animals D015306:Biogenic Monoamines D005075:Biological Evolution D001921:Brain D002555:Cerebrospinal Fluid D002642:Chick Embryo D002645:Chickens D051959:ELAV Proteins D049452:Green Fluorescent Proteins D021621:Imaging, Three-Dimensional D008297:Male D009474:Neurons D012333:RNA, Messenger D014714:Vertebrates D014981:Xenopus D015027:Zebrafish D062826:Zonula Occludens-1 Protein
monoamine dopamine serotonin ventricle hypothalamus CSF-contacting cells RRID: AB_10000240 RRID: AB_2201528 RRID: AB_221448 RRID: AB_2314334 RRID: AB_2314655 RRID: AB_477522 RRID: AB_87181 RRID: AB_94865 evolution paraventricular organ