{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:41:57Z","timestamp":1760060517004,"version":"build-2065373602"},"reference-count":90,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2025,9,6]],"date-time":"2025-09-06T00:00:00Z","timestamp":1757116800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100011033","name":"MICIU\/AEI\/10.13039\/501100011033","doi-asserted-by":"publisher","award":["PID2023-147266NB-I00"],"award-info":[{"award-number":["PID2023-147266NB-I00"]}],"id":[{"id":"10.13039\/501100011033","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biology"],"abstract":"<jats:p>The African turquoise killifish is a short-lived vertebrate that is gaining interest as a model for understanding degenerative processes associated with aging, including neurodegeneration. However, due to its relatively recent adoption in laboratory research, detailed studies on the adult neuroanatomy of the killifish, particularly regarding the organization of neurotransmitter systems and their age-related changes, remain limited. Here, we study the organization of serotonergic cell populations in the brain and spinal cord of juvenile\/young adult (1\u20133-months-old) and geriatric (5\u20136-months-old) killifish using anti-serotonin immunofluorescence. Our findings reveal that the overall organization of serotonergic cell populations in killifish closely resembles that of most teleosts, including pineal, pretectal, hypothalamic, rapheal and spinal cord neuronal populations. Of note, adult killifish also present a population of serotonergic neurons in the dorsolateral isthmus, which has been only described in a few other fish species. Aged killifish showed a similar organization of serotonergic cell populations to that of juveniles\/young adults, with the major difference being the loss of serotonin immunoreactivity in pretectal cells of 6-month-old fish. Our study provides a neuroanatomical framework for future investigations into the serotonergic system in this emerging vertebrate model of aging.<\/jats:p>","DOI":"10.3390\/biology14091206","type":"journal-article","created":{"date-parts":[[2025,9,8]],"date-time":"2025-09-08T08:06:32Z","timestamp":1757318792000},"page":"1206","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Organization of Serotonergic Cell Populations in the Brain and Spinal Cord of the Short-Lived African Turquoise Killifish"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6664-8980","authenticated-orcid":false,"given":"Laura","family":"Gonz\u00e1lez-Llera","sequence":"first","affiliation":[{"name":"Departamento de Biolox\u00eda Funcional, Facultade de Biolox\u00eda, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain"},{"name":"Aquatic One Health Research Center (ARCUS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9857-3469","authenticated-orcid":false,"given":"\u00c1lvaro J.","family":"Arana","sequence":"additional","affiliation":[{"name":"Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary Science, Universidade de Santiago de Compostela, 27002 Lugo, Spain"},{"name":"Preclinical Animal Models Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7927-5303","authenticated-orcid":false,"given":"Laura","family":"S\u00e1nchez","sequence":"additional","affiliation":[{"name":"Department of Zoology, Genetics and Physical Anthropology, Faculty of Veterinary Science, Universidade de Santiago de Compostela, 27002 Lugo, Spain"},{"name":"Preclinical Animal Models Group, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ram\u00f3n","family":"Anad\u00f3n","sequence":"additional","affiliation":[{"name":"Departamento de Biolox\u00eda Funcional, Facultade de Biolox\u00eda, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7507-080X","authenticated-orcid":false,"given":"Ant\u00f3n","family":"Barreiro-Iglesias","sequence":"additional","affiliation":[{"name":"Departamento de Biolox\u00eda Funcional, Facultade de Biolox\u00eda, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain"},{"name":"Aquatic One Health Research Center (ARCUS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,9,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1126\/science.abq4257","article-title":"Genome structures resolve the early diversification of teleost fishes","volume":"379","author":"Parey","year":"2023","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3","DOI":"10.3374\/014.065.0101","article-title":"Phylogenetic Classification of Living and Fossil Ray-Finned Fishes (Actinopterygii)","volume":"65","author":"Near","year":"2024","journal-title":"Bull. Peabody Mus. Nat. Hist."},{"key":"ref_3","first-page":"281","article-title":"Nothobranchius as a model for aging studies","volume":"5","author":"Mendiola","year":"2013","journal-title":"A Rev. Aging Dis."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"543","DOI":"10.1016\/j.tig.2016.06.006","article-title":"Nothobranchius furzeri: A Model for Aging Research and More","volume":"32","author":"Platzer","year":"2016","journal-title":"Trends Genet."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"15","DOI":"10.1016\/j.ddmod.2018.12.001","article-title":"The African turquoise killifish Nothobranchius furzeri as a model for aging research","volume":"27","author":"Reuter","year":"2018","journal-title":"Drug Discov. Today Dis. Models"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1186\/s13227-020-00170-x","article-title":"Nothobranchius annual killifishes","volume":"11","author":"Cellerino","year":"2020","journal-title":"EvoDevo"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1243","DOI":"10.1016\/S0021-9258(18)57137-4","article-title":"Serum vasoconstrictor, serotonin; isolation and characterization","volume":"176","author":"Rapport","year":"1948","journal-title":"J. Biol. Chem."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"294","DOI":"10.1016\/j.jchemneu.2011.05.009","article-title":"The serotonergic system in fish","volume":"41","author":"Lillesaar","year":"2011","journal-title":"J. Chem. Neuroanat."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"195","DOI":"10.1016\/0891-0618(92)90046-S","article-title":"The serotoninergic system of the brain of the lamprey, Lampetra fluviatilis: An evolutionary perspective","volume":"5","author":"Pierre","year":"1992","journal-title":"J. Chem. Neuroanat."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/j.jchemneu.2007.03.010","article-title":"Development of the serotonergic system in the central nervous system of the sea lamprey","volume":"34","author":"Abalo","year":"2007","journal-title":"J. Chem. Neuroanat."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.jchemneu.2008.06.001","article-title":"Development and organization of the descending serotonergic brainstem-spinal projections in the sea lamprey","volume":"36","author":"Rodicio","year":"2008","journal-title":"J. Chem. Neuroanat."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1002\/cne.21844","article-title":"Neurochemical characterization of sea lamprey taste buds and afferent gustatory fibers: Presence of serotonin, calretinin, and CGRP immunoreactivity in taste bud bi-ciliated cells of the earliest vertebrates","volume":"511","author":"Rodicio","year":"2008","journal-title":"J. Comp. Neurol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1111\/j.1469-7580.2009.01119.x","article-title":"Serotonin and GABA are colocalized in restricted groups of neurons in the larval sea lamprey brain: Insights into the early evolution of neurotransmitter colocalization in vertebrates","volume":"215","author":"Rodicio","year":"2009","journal-title":"J. Anat."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2535","DOI":"10.1089\/neu.2011.1766","article-title":"Spontaneous regeneration of the serotonergic descending innervation in the sea lamprey after spinal cord injury","volume":"28","author":"Ruiz","year":"2011","journal-title":"J. Neurotrauma"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1002\/cne.902210406","article-title":"The distribution of serotonin in the CNS of an elasmobranch fish: Immunocytochemical and biochemical studies in the Atlantic stingray, Dasyatis sabina","volume":"221","author":"Ritchie","year":"1983","journal-title":"J. Comp. Neurol."},{"key":"ref_16","first-page":"385","article-title":"Immunohistochemical demonstration of serotonin neuron system in the central nervous system of the Japanese dogfish, Scyliorhinus torazame (Chondrichthyes)","volume":"31","author":"Yamanaka","year":"1990","journal-title":"J. Hirnforsch."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1002\/cne.903080211","article-title":"Localization of serotonin, tyrosine hydroxylase, and leu-enkephalin immunoreactive cells in the brainstem of the horn shark, Heterodontus francisci","volume":"308","author":"Stuesse","year":"1991","journal-title":"J. Comp. Neurol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"414","DOI":"10.1002\/cne.903580308","article-title":"Raphe nuclei in three cartilaginous fishes, Hydrolagus colliei, Heterodontus francisci, and Squalus acanthias","volume":"358","author":"Stuesse","year":"1995","journal-title":"J. Comp. Neurol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"804","DOI":"10.1002\/cne.21857","article-title":"Development of the serotoninergic system in the central nervous system of a shark, the lesser spotted dogfish Scyliorhinus canicula","volume":"511","author":"Carrera","year":"2008","journal-title":"J. Comp. Neurol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1159\/000358266","article-title":"Organization of the serotonergic system in the central nervous system of two basal actinopterygian fishes: The Cladistians Polypterus senegalus and Erpetoichthys calabaricus","volume":"83","year":"2014","journal-title":"Brain Behav. Evol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"333","DOI":"10.1002\/(SICI)1096-9861(19990510)407:3<333::AID-CNE3>3.0.CO;2-R","article-title":"Distribution of serotonin (5HT)-immunoreactive structures in the central nervous system of two chondrostean species (Acipenser baeri and Huso huso)","volume":"407","author":"Adrio","year":"1999","journal-title":"J. Comp. Neurol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1159\/000505473","article-title":"Neuroanatomical Distribution of the Serotonergic System in the Brain and Retina of Holostean Fishes, The Sister Group to Teleosts","volume":"95","author":"Lozano","year":"2020","journal-title":"Brain Behav. Evol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1007\/BF00213771","article-title":"Serotonin in the brain of the goldfish, Carassius auratus. An immunocytochemical study","volume":"234","author":"Kah","year":"1983","journal-title":"Cell Tissue Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1007\/BF00303149","article-title":"Distribution of serotonin-immunoreactivity in the diencephalon and mesencephalon of the trout, Salmo gairdneri. Cellbodies, fibres and terminals","volume":"169","author":"Nieuwenhuys","year":"1984","journal-title":"Anat. Embryol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1002\/cne.902260302","article-title":"Distribution of 5-hydroxytryptamine (serotonin) in the brain of the teleost Gasterosteus aculeatus L.","volume":"226","year":"1984","journal-title":"J. Comp. Neurol."},{"key":"ref_26","first-page":"201","article-title":"Distribution of serotonin-immunoreactive neurons in the brain of sockeye salmon fry","volume":"2","author":"Ebbesson","year":"1989","journal-title":"J. Chem. Neuroanat."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1002\/cne.902810205","article-title":"Distribution of serotonin in the brain of the mormyrid teleost Gnathonemus petersii","volume":"281","author":"Meek","year":"1989","journal-title":"J. Comp. Neurol."},{"key":"ref_28","first-page":"429","article-title":"The distribution of serotonin in the brain of Apteronotus leptorhynchus: An immunohistochemical study","volume":"3","author":"Johnston","year":"1990","journal-title":"J. Chem. Neuroanat."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/0361-9230(93)90214-V","article-title":"Immunolocalization of catecholamine enzymes, serotonin, dopamine and L-dopa in the brain of Dicentrarchus labrax (Teleostei)","volume":"31","author":"Batten","year":"1993","journal-title":"Brain Res. Bull."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/S0891-0618(99)00049-6","article-title":"Distribution of serotonin in the brain of the Senegalese sole, Solea senegalensis: An immunohistochemical study","volume":"18","author":"Sarasquete","year":"2000","journal-title":"J. Chem. Neuroanat."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1002\/cne.21887","article-title":"Axonal projections originating from raphe serotonergic neurons in the developing and adult zebrafish, Danio rerio, using transgenics to visualize raphe-specific pet1 expression","volume":"10","author":"Lillesaar","year":"2009","journal-title":"J. Comp. Neurol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"3451","DOI":"10.1002\/cne.24938","article-title":"Serotonin distribution in the brain of the plainfin midshipman: Substrates for vocal-acoustic modulation and a reevaluation of the serotonergic system in teleost fishes","volume":"15","author":"Timothy","year":"2020","journal-title":"J. Comp. Neurol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"102033","DOI":"10.1016\/j.jchemneu.2021.102033","article-title":"Serotonin (5-hydroxytryptamine)-immunoreactive neurons in the brain of the viviparous fish Gambusia affinis","volume":"118","author":"Bhat","year":"2021","journal-title":"J. Chem. Neuroanat."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"320","DOI":"10.1002\/ar.25204","article-title":"Serotonin-immunoreactivity in the brain of the cichlid fish Oreochromis mossambicus","volume":"307","author":"Biradar","year":"2024","journal-title":"Anat. Rec."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1007\/s00429-013-0661-0","article-title":"Comparative analysis of the serotonergic systems in the CNS of two lungfishes, Protopterus dolloi and Neoceratodus forsteri","volume":"220","year":"2015","journal-title":"Brain Struct. Funct."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"4854","DOI":"10.1523\/JNEUROSCI.18-13-04854.1998","article-title":"Quantitative evaluation of 5-hydroxytryptamine (serotonin) neuronal release and uptake: An investigation of extrasynaptic transmission","volume":"1","author":"Bunin","year":"1998","journal-title":"J. Neurosci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1007\/s10571-005-3061-z","article-title":"Synaptic and extrasynaptic secretion of serotonin","volume":"25","author":"Trueta","year":"2005","journal-title":"Cell Mol. Neurobiol."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Roth, B.L. (2006). Chemical Neuroanatomy of 5-HT Receptor Subtypes in the Mammalian Brain. The Serotonin Receptors, Humana Press. The Receptors.","DOI":"10.1007\/978-1-59745-080-5"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1146\/annurev.med.60.042307.110802","article-title":"The expanded biology of serotonin","volume":"60","author":"Berger","year":"2009","journal-title":"Annu. Rev. Med."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"2382","DOI":"10.1098\/rstb.2011.0378","article-title":"Probing the diversity of serotonin neurons","volume":"5","author":"Gaspar","year":"2012","journal-title":"Philos. Trans. R. Soc. Lond. B Biol. Sci."},{"key":"ref_41","first-page":"924","article-title":"Serotonin Promotes Development and Regeneration of Spinal Motor Neurons in Zebrafish","volume":"3","author":"Mysiak","year":"2015","journal-title":"Cell Rep."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"317","DOI":"10.1093\/cz\/zow037","article-title":"Role of brain serotonin in modulating fish behavior","volume":"62","author":"Winberg","year":"2016","journal-title":"Curr. Zool."},{"key":"ref_43","first-page":"dmm037085","article-title":"Serotonin inhibits axonal regeneration of identifiable descending neurons after a complete spinal cord injury in lampreys","volume":"20","author":"Robledo","year":"2019","journal-title":"Dis. Models Mech."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1007\/s10522-012-9406-3","article-title":"Serotonin: From top to bottom","volume":"14","author":"Fidalgo","year":"2013","journal-title":"Biogerontology"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/0304-3940(88)90638-6","article-title":"Aberrant morphology of serotonergic fibers in the forebrain of the aged rat","volume":"95","author":"Steinbusch","year":"1988","journal-title":"Neurosci. Lett."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"201","DOI":"10.1016\/0197-4580(92)90032-S","article-title":"Aging of the serotonergic system in the rat forebrain: An immunocytochemical and neurochemical study","volume":"13","author":"Tonnaer","year":"1992","journal-title":"Neurobiol. Aging"},{"key":"ref_47","first-page":"185","article-title":"The effect of age on the monoamines of the hypothalamus","volume":"13","author":"Machado","year":"1995","journal-title":"Mech. Ageing Dev."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1007\/s004010050939","article-title":"Vulnerability to aging in the rat serotonergic system","volume":"96","author":"Nishimura","year":"1998","journal-title":"Acta Neuropathol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/0197-4580(86)90021-7","article-title":"Immunocytochemical changes in serotonin in the forebrain and pituitary of aging fish","volume":"7","author":"Schreibman","year":"1986","journal-title":"Neurobiol. Aging"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"265","DOI":"10.1089\/zeb.2021.0001","article-title":"Effects of Sex and Group Size on Behavior and Brain Biogenic Amines in Short-Lived Turquoise Killifish (Nothobranchius furzeri)","volume":"18","author":"Evsiukova","year":"2021","journal-title":"Zebrafish"},{"key":"ref_51","doi-asserted-by":"crossref","unstructured":"Evsiukova, V.S., Arefieva, A.B., Sorokin, I.E., and Kulikov, A.V. (2023). Age-Related Alterations in the Level and Metabolism of Serotonin in the Brain of Males and Females of Annual Turquoise Killifish (Nothobranchius furzeri). Int. J. Mol. Sci., 6.","DOI":"10.3390\/ijms24043185"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1007\/s00441-023-03845-8","article-title":"Immunohistochemical characterisation of the adult Nothobranchius furzeri intestine","volume":"395","author":"Borgonovo","year":"2024","journal-title":"Cell Tissue Res."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"e12757","DOI":"10.1111\/acel.12757","article-title":"The African turquoise killifish: A research organism to study vertebrate aging and diapause","volume":"17","author":"Hu","year":"2018","journal-title":"Aging Cell"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"463","DOI":"10.1007\/BF01740772","article-title":"The paraventricular and posterior recess organs of elasmobranchs: A system of cerebrospinal fluid-contacting neurons containing immunoreactive serotonin and somatostatin","volume":"259","author":"Meurling","year":"1990","journal-title":"Cell Tissue Res."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1111\/j.1460-9568.2008.06368.x","article-title":"Serotoninergic modulation of sensory transmission to brainstem reticulospinal cells","volume":"28","author":"Antri","year":"2008","journal-title":"Eur. J. Neurosci."},{"key":"ref_56","first-page":"2680","article-title":"Social status differences regulate the serotonergic system of a cichlid fish, Astatotilapia burtoni","volume":"217","author":"Loveland","year":"2014","journal-title":"J. Exp. Biol."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"101708","DOI":"10.1016\/j.jchemneu.2019.101708","article-title":"Serotonin systems in three socially communicating teleost species, the grunting toadfish (Allenbatrachus grunniens), a South American marine catfish (Ariopsis seemanni), and the upside-down catfish (Synodontis nigriventris)","volume":"104","author":"Rosner","year":"2020","journal-title":"J. Chem. Neuroanat."},{"key":"ref_58","doi-asserted-by":"crossref","unstructured":"Borgonovo, J., Ahumada-Galleguillos, P., O\u00f1ate-Ponce, A., Allende-Castro, C., Henny, P., and Concha, M.L. (2021). Organization of the Catecholaminergic System in the Short-Lived Fish Nothobranchius furzeri. Front. Neuroanat., 15.","DOI":"10.3389\/fnana.2021.728720"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"587","DOI":"10.1007\/s00429-012-0412-7","article-title":"The sea lamprey tryptophan hydroxylase: New insight into the evolution of the serotonergic system of vertebrates","volume":"218","author":"Rodicio","year":"2013","journal-title":"Brain Struct. Funct."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1159\/000114378","article-title":"Serotoninergic and enkephalinergic cell groups in the reticular formation of the bat ray and two skates","volume":"38","author":"Stuesse","year":"1991","journal-title":"Brain Behav. Evol."},{"key":"ref_61","first-page":"297","article-title":"Serotonin-immunoreactive neurons in the brain of Eigenmannia lineata (Gymnotiformes, Teleostei)","volume":"31","author":"Bonn","year":"1990","journal-title":"J. Hirnforsch."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/0891-0618(91)90033-9","article-title":"Distribution of serotonin- and dopamine-immunoreactivity in the brain of the teleost Clarias gariepinus","volume":"4","author":"Corio","year":"1991","journal-title":"J. Chem. Neuroanat."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1006\/gcen.1993.1116","article-title":"Immunocytochemical localization of serotonin and gonadotropin-releasing hormone in the brain and pituitary gland of the Atlantic croaker Micropogonias undulatus","volume":"91","author":"Khan","year":"1993","journal-title":"Gen. Comp. Endocrinol."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1111\/j.1474-9726.2011.00781.x","article-title":"Adult neurogenesis in the short-lived teleost Nothobranchius furzeri: Localization of neurogenic niches, molecular characterization and effects of aging","volume":"11","author":"Tozzini","year":"2012","journal-title":"Aging Cell"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"S215","DOI":"10.1016\/S0925-4773(03)00119-9","article-title":"Cloning of two tryptophan hydroxylase genes expressed in the diencephalon of the developing zebrafish brain","volume":"119","author":"Bellipanni","year":"2002","journal-title":"Mech. Dev."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"2265","DOI":"10.1007\/s00429-021-02322-8","article-title":"Distribution of two isoforms of tryptophan hydroxylase in the brain of rainbow trout (Oncorhynchus mykiss). An in situ hybridization study","volume":"226","author":"Chivite","year":"2021","journal-title":"Brain Struct. Funct."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1007\/s004410050621","article-title":"Central projections of the parapineal organ of the adult rainbow trout (Oncorhynchus mykiss)","volume":"285","author":"Meissl","year":"1996","journal-title":"Cell Tissue Res."},{"key":"ref_68","first-page":"171","article-title":"Afferent and efferent connections of the parapineal organ in lampreys: A tract tracing and immunocytochemical study","volume":"11","author":"Pombal","year":"1999","journal-title":"J. Comp. Neurol."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1159\/000265306","article-title":"Photosensitivity and biosynthesis of indole compounds in the cells of the receptor line of the pineal organ of the pike","volume":"16","year":"1984","journal-title":"Ophthalmic Res."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1159\/000109128","article-title":"Three-dimensional reconstruction of serotonin-immunoreactive photoreceptors in the pineal organ of the river lamprey, Lampetra japonica","volume":"6","author":"Tamotsu","year":"1997","journal-title":"Neurosignals"},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1007\/s004410051227","article-title":"Cholinergic and GABAergic neuronal elements in the pineal organ of lampreys, and tract-tracing observations of differential connections of pinealofugal neurons","volume":"295","author":"Pombal","year":"1999","journal-title":"Cell Tissue Res."},{"key":"ref_72","doi-asserted-by":"crossref","unstructured":"Koyanagi, M., Wada, S., Kawano-Yamashita, E., Hara, Y., Kuraku, S., Kosaka, S., Kawakami, K., Tamotsu, S., Tsukamoto, H., and Shichida, Y. (2015). Diversification of non-visual photopigment parapinopsin in spectral sensitivity for diverse pineal functions. BMC Biol., 13.","DOI":"10.1186\/s12915-015-0174-9"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"905","DOI":"10.1210\/endo.139.3.5790","article-title":"Transcripts encoding two melatonin synthesis enzymes in the teleost pineal organ: Circadian regulation in pike and zebrafish, but not in trout","volume":"139","author":"Cahill","year":"1998","journal-title":"Endocrinology"},{"key":"ref_74","first-page":"101905","article-title":"The core circadian component, Bmal1, is maintained in the pineal gland of old killifish brain","volume":"9","author":"Lee","year":"2020","journal-title":"iScience"},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1002\/cne.902810109","article-title":"Serotoninergic neurons in the mormyrid brain and their projection to the preelectromotor and primary electrosensory centers: Immunohistochemical study","volume":"1","author":"Grant","year":"1989","journal-title":"J. Comp. Neurol."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1016\/j.neures.2006.10.004","article-title":"Fiber connections of the periventricular pretectal nucleus in a teleost, tilapia (Oreochromis niloticus)","volume":"57","author":"Xue","year":"2007","journal-title":"Neurosci. Res."},{"key":"ref_77","first-page":"1017","article-title":"Neural connections of the pretectum in zebrafish (Danio rerio)","volume":"15","author":"Quelle","year":"2018","journal-title":"J. Comp. Neurol."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"1127","DOI":"10.1016\/0306-4522(85)90282-9","article-title":"Distribution of serotonergic neurons and processes in the lamprey spinal cord","volume":"14","author":"McPhee","year":"1985","journal-title":"Neuroscience"},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1002\/cne.902240307","article-title":"The descending and intrinsic serotoninergic innervation of an elasmobranch spinal cord","volume":"10","author":"Ritchie","year":"1984","journal-title":"J. Comp. Neurol."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1002\/dneu.22352","article-title":"Intraspinal serotonergic neurons consist of two, temporally distinct populations in developing zebrafish","volume":"76","author":"Montgomery","year":"2016","journal-title":"Dev. Neurobiol."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"807","DOI":"10.1002\/dneu.22606","article-title":"Intraspinal serotonergic signaling suppresses locomotor activity in larval zebrafish","volume":"78","author":"Montgomery","year":"2018","journal-title":"Dev. Neurobiol."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"559","DOI":"10.1007\/BF00228440","article-title":"Serotonin and opsin immunoreactivities in the developing pineal organ of the three-spined stickleback, Gasterosteus aculeatus L.","volume":"237","author":"Nyberg","year":"1984","journal-title":"Cell Tissue Res."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1159\/000113915","article-title":"Immunohistochemical study of the development of serotoninergic neurons in the brain of the brook trout Salvelinus fontinalis","volume":"40","author":"Bolliet","year":"1992","journal-title":"Brain Behav. Evol."},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1002\/cne.20281","article-title":"Relationship of tyrosine hydroxylase and serotonin immunoreactivity to sensorimotor circuitry in larval zebrafish","volume":"29","author":"McLean","year":"2004","journal-title":"J. Comp. Neurol."},{"key":"ref_85","doi-asserted-by":"crossref","first-page":"1072","DOI":"10.1002\/dvdy.21095","article-title":"The serotonergic phenotype is acquired by converging genetic mechanisms within the zebrafish central nervous system","volume":"236","author":"Lillesaar","year":"2007","journal-title":"Dev. Dyn."},{"key":"ref_86","doi-asserted-by":"crossref","first-page":"e13594","DOI":"10.1111\/cpr.13594","article-title":"An in vivo drug screen in zebrafish reveals that cyclooxygenase 2-derived prostaglandin D2 promotes spinal cord neurogenesis","volume":"57","year":"2024","journal-title":"Cell Prolif."},{"key":"ref_87","doi-asserted-by":"crossref","first-page":"1727","DOI":"10.1016\/j.celrep.2019.01.015","article-title":"Age- and \u03b1-Synuclein-Dependent Degeneration of Dopamine and Noradrenaline Neurons in the Annual Killifish Nothobranchius furzeri","volume":"12","author":"Matsui","year":"2019","journal-title":"Cell Rep."},{"key":"ref_88","doi-asserted-by":"crossref","first-page":"e13689","DOI":"10.1111\/acel.13689","article-title":"Quantification of noradrenergic-, dopaminergic-, and tectal-neurons during aging in the short-lived killifish Nothobranchius furzeri","volume":"21","author":"Bagnoli","year":"2022","journal-title":"Aging Cell"},{"key":"ref_89","doi-asserted-by":"crossref","first-page":"102019","DOI":"10.1016\/j.arr.2023.102019","article-title":"Turquoise killifish: A natural model of age-dependent brain degeneration","volume":"90","author":"Valenzano","year":"2023","journal-title":"Ageing Res Rev."},{"key":"ref_90","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1038\/s41514-021-00077-4","article-title":"The killifish visual system as an in vivo model to study brain aging and rejuvenation","volume":"17","author":"Vanhunsel","year":"2021","journal-title":"NPJ Aging Mech. Dis."}],"container-title":["Biology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-7737\/14\/9\/1206\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T18:41:23Z","timestamp":1760035283000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-7737\/14\/9\/1206"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,6]]},"references-count":90,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2025,9]]}},"alternative-id":["biology14091206"],"URL":"https:\/\/doi.org\/10.3390\/biology14091206","relation":{},"ISSN":["2079-7737"],"issn-type":[{"type":"electronic","value":"2079-7737"}],"subject":[],"published":{"date-parts":[[2025,9,6]]}}}