Long-lasting LTP requires neither repeated trains for its induction nor protein synthesis for its development.
Current thinking about LTP triggered in the area CA1 of hippocampal slices is ruled by two "dogmas": (1) A single train of high-frequency stimulation is sufficient to trigger short-lasting LTP (1-3 h), whereas multiple trains are required to induce long-lasting LTP (L-LTP, more than 4 h). (2) The development of the late phase of L-LTP requires the synthesis of new proteins. In this study, we found that a single high-frequency train could trigger an LTP lasting more than 8 h that was not affected by either anisomycin or cycloheximide (two inhibitors of protein synthesis). We ascertained that the induction of this L-LTP made use of the same mechanisms as those usually reported to be involved in LTP induction: it was dependent on NMDA receptors and on the activation of two "core" kinases, CaMKII and PI3K. These findings call into question the two "dogmas" about LTP.
Department of Neurosciences, University of Mons, Mons, Belgium.
Agnès
A
Villers
Emile
E
Godaux
Laurence
L
Ris
D000818:Animals; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism; D004558:Electric Stimulation; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D017774:Long-Term Potentiation / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D051379:Mice; D016202:N-Methylaspartate / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism
D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D016202:N-Methylaspartate; D019869:Phosphatidylinositol 3-Kinases; D011500:Protein Synthesis Inhibitors; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate