Distribution of GABAergic Neurons in the Neocortex in Rats during the Postnatal Period after Perinatal Hypoxia

The distribution of GABAergic neurons in different areas of the neocortex (frontal, sensorimotor, and visual) was studied in Wistar rats at different time points in the postnatal period of development after exposure to perinatal hypoxia. These neurons were detected using antibodies to GAD-67, a marker for GABAergic neurons. Perinatal hypoxia was found to lead to significant decreases in the numbers of GAD-67-expressing neurons in both the upper and the deep layers of the cortex at juvenile age (at day 20 of postnatal development), persisting to the pubertal period (day 40). The number of GAD-67-synthesizing neurons in each of the neocortical layers in experimental animals on day 40 were half those in controls. The sharp decrease in the number of GABAergic neurons in the neocortex is probably due to the harmful action of acute perinatal hypoxia on precursor cell migration from the subventricular zone or on the synthesis of the factors controlling these migration processes and the maturation of GABAergic neurons, and thus decreasing the late expression of GAD-67. © 2015, Springer Science+Business Media New York.