Glucocorticoid receptor expression in the different cell types of the neonatal rat hippocampus and cortex

Glucocorticoids (GC) are crucial regulator of organism homeostasis and function. Despite severe outcome glucocorticoid therapy in neonates is widely used antenataly for accelerating fetal lung maturation in cases of preterm birth. GC action mediated via glucocorticoid receptors – ligand activated transcription factors. Despite broad range of information concerning GR expression in the brain, not so much known about GR expression in the neonatal brain in aspects of cell specificity and identity. In this work we perform comparative study of GR expression together with panel of main neuronal and astrocytic cell markers in the neonatal rat brain. We immunohistochemically studied GR expression in the hippocampal CA1 field and enthorinal cortex together with cortical projection neuron markers – SATB2, NURR1; Calretenin – interneurons marker, and GFAP – astrocytic marker. The highest calocalization coefficients observed for GR with Calrtetenin. With projection neuron markers that are also transcription factors calocalization coefficients increased to the same values as for GR-Calretenin 6h after dexamethasone injection and GR were translocated to the nucleus. Our analysis showed that in the neonatal rat brain GR are more localized in neurons than in astocytes.