HIPPOCAMPAL LONG-TERM POTENTIATION IN-VIVO INDUCES TRANSLOCATION OF PROTEIN-KINASE C-GAMMA

THE possible involvement of the Ca2+-dependent protein kinase C (PKC) isoenzymes alpha/beta and gamma in mechanisms of long-term potentiatio n (LTP) was investigated after tetanic stimulation of the perforant pa th in vivo. Brief tetanic stimulation of the perforant path resulted i n a 150% increase in population spike amplitude recorded from the dent ate gyrus synapses in response to test stimuli 5 and 10 min after teta nization. Immunoblot analysis of PKC immunoreactivity in cytosolic and membrane fractions revealed a LTP-induced translocation of gamma PKC but not alpha/beta PKC into the cytosol in dentate gyrus but also in t he other ipsilateral hippocampal regions. These data suggest different physiological roles of Ca2+-dependent PKC isoenzymes in activity-depe ndent synaptic plasticity.