LOCALIZATION OF GLUCOCORTICOID RECEPTORS AND GLUCOCORTICOID RECEPTOR MESSENGER-RNAS IN THE RAT COCHLEA

The distribution of glucocorticoid (GR) receptor messenger RNAs (mRNAs ) and GR receptors was studied by in situ hybridization histochemistry and immunocytochemistry, respectively. In situ hybridization histoche mistry was performed with a biotin-labeled riboprobe complementary to rat GR receptor mRNA. GR receptor mRNAs were demonstrated in spiral li gament cells, spiral limbus cells, and spiral ganglion cells. GR recep tor mRNAs were demonstrated neither in cells of the stria vascularis n or in cells of the organ of Corti region. With the use of a monoclonal and a polyclonal antibody, GR receptors were observed in the spiral l igament cells, stria vascularis cells, spiral limbus cells, and spiral ganglion cells by immunocytochemistry. Binding of anti-GR-receptor an tibodies to a lesser extent was observed in the organ of Corti region; however, cellular distribution of the GR receptors could not be resol ved with the applied techniques. These results suggest that the GR rec eptor is expressed differently in the heterogeneous cochlear tissues.