Implication of protein kinase C in mechanisms of potassium-induced long-term potentiation in rat hippocampal slices.
The involvement of Ca2+/phospholipid-dependent (alpha, beta, gamma, PKCs) and Ca(2+)-independent PKC (epsilon and zeta isoforms) in mechanisms of long-term potentiation was investigated in CA1 hippocampal slices, using a brief high potassium pulse (50 mM, 40 s) to induce long-term potentiation (K+/LTP). The K+ pulse induced first, in 15 s a translocation of PKC activity to the membrane. This was rapidly followed, from 1 to 60 min after the pulse, by a selective activation of PKC in the cytosol. This activation, which could be blocked by the NMDA (N-methyl-D-aspartate) receptor antagonist 2-amino-5-phosphonovalerate (APV), was associated with a significant increase n immunoreactivity for gamma PKC in he cytosol, and also to a less degree for beta PKC. In contrast, application of the phorbol ester PMA (phorbol 12-mirystate 13 acetate) to other slices induced a rapid and persistent translocation to the membrane of alpha, beta, epsilon and zeta PKCs. A major role for the activation role for the activation of cytosolic gamma PKC in the maintenance of LTP is discussed.
Roisin
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MP
Université René Descartes, Paris C, INSERM U 29, Hopital de Port-Royal, Paris, France.
Leinekugel
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Tremblay
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D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D004558:Electric Stimulation; D004594:Electrophysiology; D004789:Enzyme Activation / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000201:enzymology; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000378:metabolism*; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D010703:Phorbol Esters / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007527:Isoenzymes; D010703:Phorbol Esters; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D011188:Potassium