Adult and Reparative Neurogenesis in Fish Brain

Abstract

The fish brain has a unique feature of vertebrates-it grows with the growth of body over a lifetime. In this regard, fishes are a convenient model for the study of embryonic and postembryonic development of the central nervous system and of the influence of different factors on these processes. Currently, the mechanisms of adult brain morphogenesis of fish, which retain larval stage for a long time, are poorly understood. This is particularly true for participation of radial glia during morphogenesis of the brain, as well as the presence and distribution of the proliferative zone in the adult fish brain. Another interesting and little known aspect is the posttraumatic ability of fish to form active neurogenic niches. Investigation of the structural organizations of neurogenic niches and special conditions of the extracellular environment, as well as the interactions between neighboring cells in a neurogenic niche, is interesting and relevant direction in the study of the neuronal stem cells biology. Injury of fish brain creates special conditions for the implementation of genetic programs aimed at strengthening the proliferation of progenitor cells, as well as the activation and proliferation activity in the neuronal stem cells.

Hydrogen Sulfide Modulates Adult and Reparative Neurogenesis in the Cerebellum of Juvenile Masu Salmon, Oncorhynchus masou

“…Salmonids, which are a phylogenetically ancient group, have a high concentration of undifferentiated elements, both in the matrix zones of the brain and in the parenchyma [ 11 ]. Their ontogenesis is characterized by such phenomena as developmental delay and retention of signs of the embryonic organization of CNS which occur at the stage of active brain growth, where the morphogenesis processes are most clearly and fully expressed [ 11 ].…”

“…Salmonids, which are a phylogenetically ancient group, have a high concentration of undifferentiated elements, both in the matrix zones of the brain and in the parenchyma [ 11 ]. Their ontogenesis is characterized by such phenomena as developmental delay and retention of signs of the embryonic organization of CNS which occur at the stage of active brain growth, where the morphogenesis processes are most clearly and fully expressed [ 11 ]. This feature of salmon CNS development, referred to as embrionalization, is confirmed by the presence of a large number of embryonic neuronal stem cells (NSCs) corresponding to cells of the neuroepithelial (NE) type, as well as radial glial (RG) cells corresponding to adult progenitors [ 12 , 13 , 14 , 15 ].…”

Adult Neurogenesis of Teleost Fish Determines High Neuronal Plasticity and Regeneration

“…Juveniles in the first year are an extremely actively growing stage in the development of Pacific salmon. In natural conditions, they are preparing for the process of smoltification, accompanied by the activation of extremely adverse environmental conditions, including the transition from a freshwater environment to a marine one, which is in turn accompanied by the restructuring of all body systems [30,31]. In the life cycle of Pacific salmon, researchers distinguish four stages, which differ significantly from each other both in the combination and ratio of limiting factors, which affect each of them and the level of natural mortality [32].…”