EXPRESSION OF IONOTROPIC GLUTAMATE-RECEPTOR SUBUNIT MESSENGER-RNAS BYPARAVENTRICULAR CORTICOTROPIN-RELEASING FACTOR (CRF) NEURONS

To determine whether paraventricular corticotropin-releasing factor (C RF) neurons express NMDA, AMPA or kainate-preferring glutamate recepto rs, we have colocalized, by in situ hybridization (ISH), transcripts o f various glutamate receptor subunit genes with the CRF messenger RNA on doublet adjacent sections of the rat hypothalamus. We found that mo re than 70% of CRF-positive neurons contain the NMDA receptor subunit NR1 mRNA whereas NR2A and NR2B subunit mRNAs were not detectable in CR F cells. A significant proportion of identified CRF cells express AMPA receptor subunit GluRA (46%), GluRB (21%) as well as the kainate-pref erring receptor subunit KA2 (31%) mRNAs. These results support the hyp othesis that the excitatory transmitter glutamate may directly influen ce CRF neurons through NMDA as well as non-NMDA receptors.