IDENTIFICATION OF FUNCTIONAL IONOTROPIC GLUTAMATE-RECEPTOR PROTEINS IN PANCREATIC BETA-CELLS AND IN ISLETS OF LANGERHANS

The presence of ionotropic glutamate receptor proteins in islets of La ngerhans and pancreatic beta-cell Lines (MIN6, HIT T15, RINm5F) was in vestigated, For this purpose immunoblot analysis of beta-cell membrane s was performed with subunit-specific antibodies, We identified NMDAR1 subunits of the NMDA and KA-2 subunits of the kainate receptors, but did not detect GluR1 subunits of the AMPA receptor, The receptor subun its present were shown to be glycosylated. beta-cell membranes contain ed specific binding sites for glutamate receptor ligands, and NMDA inc reased insulin secretion, These results demonstrate that ionotropic gl utamate receptor proteins, similar to those in the central nervous sys tem, are expressed in rat pancreatic beta-cells.