Comparative analysis of monoaminergic cerebrospinal fluid-contacting cells in Osteichthyes (bony vertebrates). - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Comparative Neurology Année : 2017

Comparative analysis of monoaminergic cerebrospinal fluid-contacting cells in Osteichthyes (bony vertebrates).

Résumé

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.

Dates et versions

hal-01572232 , version 1 (05-08-2017)

Identifiants

Citer

Anna L Xavier, Romain Fontaine, Solal Bloch, Pierre Affaticati, Armin Jenett, et al.. Comparative analysis of monoaminergic cerebrospinal fluid-contacting cells in Osteichthyes (bony vertebrates).. Journal of Comparative Neurology, 2017, 525 (9), pp.2265-2283. ⟨10.1002/cne.24204⟩. ⟨hal-01572232⟩
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