ANTIBODIES TO POSTSYNAPTIC PKC SUBSTRATE NEUROGRANIN PREVENT LONG-TERM POTENTIATION IN HIPPOCAMPAL CA1 NEURONS

Both pre- and postsynaptic protein kinase C have been implicated in lo ng-term potentiation. Neurogranin (also known as BICKs and RC3) is a n euronal postsynaptic protein kinase C substrate. In the present study we injected monoclonal IgGs that recognize the protein kinase C phosph orylation site in neurogranin and B-50 (GAP-43), and that have been sh own to inhibit protein kinase C-mediated B-50 phosphorylation, through a whole-cell clamp pipette into CA1 pyramidal neurons in rat hippocam pal slices. Injection of neurogranin IgGs, but not of control IgGs, pr evented the induction of tetanus-induced long-term potentiation withou t affecting posttetanic potentiation. Our results suggest that neurogr anin is involved in mechanisms of activity-dependent synaptic plastici ty.