A population of prenatally generated cells in the rat paleocortex maintains an immature neuronal phenotype into adulthood.
New neurons in the adult brain transiently express molecules related to neuronal development, such as the polysialylated form of neural cell adhesion molecule, or doublecortin (DCX). These molecules are also expressed by a cell population in the rat paleocortex layer II, whose origin, phenotype, and function are not clearly understood. We have classified most of these cells as a new cell type termed tangled cell. Some cells with the morphology of semilunar-pyramidal transitional neurons were also found among this population, as well as some scarce cells resembling semilunar, pyramidal. and fusiform neurons. We have found that none of these cells in layer II express markers of glial cells, mature, inhibitory, or principal neurons. They appear to be in a prolonged immature state, confirmed by the coexpression of DCX, TOAD/Ulip/CRMP-4, A3 subunit of the cyclic nucleotide-gated channel, or phosphorylated cyclic adenosine monophosphate response element-binding protein. Moreover, most of them lack synaptic contacts, are covered by astroglial lamellae, and fail to express cellular activity markers, such as c-Fos or Arc, and N-methyl-d-aspartate or glucocorticoid receptors. We have found that none of these cells appear to be generated during adulthood or early youth and that most of them have been generated during embryonic development, mainly in E15.5.
Gómez-Climent
María Angeles
MA
Neurobiology Unit and Program in Basic and Applied Neurosciences, Cell Biology Dpt., Universitat de València, Spain.
Castillo-Gómez
Esther
E
Varea
Emilio
E
Guirado
Ramón
R
Blasco-Ibáñez
José Miguel
JM
Crespo
Carlos
C
Martínez-Guijarro
Francisco José
FJ
Nácher
Juan
J
D000367:Age Factors; D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D015415:Biomarkers / Q000378:metabolism; D001973:Bromodeoxyuridine / Q000494:pharmacology; D000089662:Doublecortin Protein; D018728:Entorhinal Cortex / Q000166:cytology* / Q000196:embryology*; D005260:Female; D016130:Immunophenotyping; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008854:Microscopy, Electron; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism; D011247:Pregnancy; D017966:Pyramidal Cells / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism
D000963:Antimetabolites; D015415:Biomarkers; C000714847:Dcx protein, mouse; C000714848:Dcx protein, rat; D000089662:Doublecortin Protein; D039842:Neural Cell Adhesion Molecule L1; D011965:Receptors, Glucocorticoid; D016194:Receptors, N-Methyl-D-Aspartate; D012794:Sialic Acids; C103469:polysialyl neural cell adhesion molecule; D001973:Bromodeoxyuridine