Abstract
An RTโPCR analysis revealed constitutive expression of mRNA for NโmethylโDโaspartate (NMDA) receptor (NR)โ1, NRโ2C, and NRโ2D subunits in rat adrenal and pituitary glands, in addition to brain and retina. Constitutive expression of mRNA was detected for the NRโ2A subunit in pituitary but not adrenal gland. Although on Western blotting assays adrenal medulla exhibited expression of NRโ1 subunit protein without expression of NRโ2C and NRโ2D subunit proteins, an immunohistochemical investigation clearly showed selective localization of proteins for NRโ1, NRโ2C, and NRโ2D subunits in adrenal medulla but not in adrenal cortex. Prior treatment with different glycosidases invariably resulted in a marked increase in immunoreactivity to the antiโNRโ1 antibody in both hippocampus and adrenal medulla. An intraperitoneal injection of a blocker of NMDA receptor channel, but not NMDA itself, led to marked potentiation of DNA binding activity of the transcription factor activator proteinโ1 in adrenal nuclear extracts 2 hr after administration. These results suggest that heteromeric NMDA receptor channels may be constitutively and functionally expressed with glycosylation of NRโ1 subunit under the influence of tonic stimulation by circulating agonists such as Lโglutamate in rat adrenal medulla. ยฉ 2002 WileyโLiss, Inc.