title: [Initial stages of differentiation of pyramidal neurons in deep layers of the mouse neocortex in the prenatal period].
abstract: The time of initiation of neuron differentiation in deep neocortical layers was determined in mouse embryos and total effect of ionizing radiation on the developing mouse brain was evaluated. The population of cells that form layers V and VI with differentiation occurring in a half of them was shown to be present in mice embryos on d13. This population comprises both non differentiated neuroblasts and juvenile neurons of certain level of differentiation. They make the half of total population and their number remains unchanged on d14. Irradiation of mouse embryos at early postimplantation stage (d12) causes severe disturbances of neocortex development that are conditioned by massive cell death, abnormal development of all the brain structures and reduction of brain volume. Irradiation of mice embryos on d 13 and 14 induces massive death of migrating and mitotic cells in populations responsible for forming deep cortical layers. By the end of prenatal period either lack or insufficient development of layers V and VI was observed manifested in significant decline of cell number, spacing out and loss of neurons in certain regions. In embryos irradiated within these terms upper layers of cortex may form, although density of cell distribution in them is lower than in control.
authors.affiliation: Department of Morphology, Institute of the Experimental Medicine, RAMS, St. Petersburg.
authors.forename: L I
authors.initials: LI
authors.lastname: Khozhaĭ
authors.forename: V A
authors.initials: VA
authors.lastname: Otellin
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008938:Mitosis; D019579:Neocortex / Q000033:anatomy & histology / Q000166:cytology* / Q000196:embryology / Q000528:radiation effects; D017966:Pyramidal Cells / Q000502:physiology* / Q000528:radiation effects; D011839:Radiation, Ionizing