The localization of glucocorticoid receptor (GR) immunoreactivity and mRNA in the adult rat brain was examined by light microscopic and electron microscopic immunohistochemistries
and in situ hybridization. For the purpose of detailed investigation of the distribution and comparison of GR immunoreactivities and mRNAs
specific polyclonal antibodies against a part of the transcription modulation (TR) domain of rat GR were used in the immunohistochemistry
whereas fluorescein-labeled RNA probes
complementary to the TR domain in the GR cDNA were used in the in situ hybridization. In the rat brain
GR immunoreactivity was predominantly localized in the cell nucleus
and the expression of GR mRNA was detected in the cytoplasm. GR-immunoreactive and GR mRNA-containing cells were widely distributed from the olfactory bulb of the forebrain to the gracile-cuneate nuclei of the medulla oblongata. The highest densities of GR-immunoreactive and mRNA-containing cells were observed in the subfields of cerebral cortex
olfactory cortex
hippocampal formation
amygdala
septal region
dorsal thalamus
hypothalamus
trapezoid body
cerebellar cortex
locus coeruleus and dorsal nucleus raphe. The distributional pattern of GR immunoreactivity in many regions was well-correlated with that of GR mRNA
but in the CA3 and CA4 pyramidal layers of the hippocampus
different localization was noted. The present study provides the groundwork for elucidating the role of GRs in brain function.
