Subgranular Zone of the Dentate Gyrus of Young Rabbits As a Secondary Matrix

Abstract

Cell genesis in the subgranular zone of the dentate gyrus of 2-month-old rabbits has been investigated. After incorporation of tritiated thymidine, electron microscopic autoradiography allowed description of the ultrastructure of the cells labelled and the progressive transformation of these cells into granular neurons to be followed. Quantitative evaluation of the time course of this transformation has been performed by light microscope autoradiography using 1-µm sections. Precursor cells, labelled initially with ³H-thymidine, were transformed after 5 days into early neuroblasts, these cells in turn giving rise to neurons some 8 days later. At the latest time period examined (42 days), 80% of the labelled cells were neurons; more than 10% remained as precursor cells. It is suspected that the latter may behave as reserve cells. Small numbers of glial cells, astrocytes, and microglia, scattered throughout the talus of the dentate gyrus and the molecular layer, were found labelled, and it is possible that they arise from a different precursor pool. It is concluded that the subgranular zone functions as a secondary matrix for granule neurons of the dentate gyrus in young rabbits. These late-forming and apparently synaptically uncommitted neurons may be recruited during the development and refinement of postnatal behavioral substrates, by one or other of the dominant afferent systems.

Adult Hippocampal Neurogenesis in Natural Populations of Mammals

“…Using BrdU in combination with Sox2, DCX, NeuN, and S100, the agedependent regulation of AHN in sheep has been investigated in detail (Brus et al 2013b). Hippocampal proliferation has been shown in rabbits (Oryctolagus cuniculus, order Lagomorpha), using 3 H-thymidine (Gueneau et al 1982) and RNR, GFAP, calbindin, neurofilament, and nestin (Zhu et al 2003). Interestingly, rabbits show neurogenesis in more brain regions than rodents (for review, see Bonfanti and Ponti 2008).…”

Enhanced Synaptic Integration of Adult-Born Neurons in the Olfactory Bulb of Lactating Mothers

“…In addition, dendritic morphology (i.e., dendritic length and number of branch points) has been shown to be modulated by motherhood in both CA1 and CA3 neurons (Pawluski and Galea, 2006). Particularly relevant are changes in the hippocampus, which is the other main neurogenic region of the mammalian brain (Altman and Das, 1965;Guéneau et al, 1982;Gross, 2000;Ming and Song, 2005). Although no cell proliferation was reported during pregnancy in the hippocampus (Shingo et al, 2003;Furuta and Bridges, 2005;Pawluski et al, 2010), the possibility of heightened neuronal plasticity of adult generated neurons remains an open matter to explore.…”

Dentate Granule Cell Neurogenesis Is Increased by Seizures and Contributes to Aberrant Network Reorganization in the Adult Rat Hippocampus

“…Among the principal neuronal populations within the hippocampal formation, the dentate granule cells have the unusual property of prolonged postnatal neurogenesis Das, 1965, 1967;Gueneau et al, 1982;Eckenhoff and Rakic, 1988) that persists into adulthood in the rodent (Kaplan and Hinds, 1977;Bayer and Yackel, 1982;Kaplan and Bell, 1984;Cameron et al, 1993b;Seki and Arai, 1993;Kuhn et al, 1996). In the adult rat, neuronal precursors reside in the SGZ of the dentate gyrus, where they proliferate and migrate continuously into the granule cell layer (Cameron et al, 1993b;Seki and Arai, 1993;Kuhn et al, 1996).…”