TY  - JOUR
A1  - Sanna, Pietro Paolo
A1  - Cammalleri, Maurizio
A1  - Berton, Fulvia
A1  - Simpson, Cindy
A1  - Lutjens, Robert
A1  - Bloom, Floyd E.
A1  - Francesconi, Walter
T1  - Phosphatidylinositol 3-Kinase Is Required for the Expression But Not for the Induction or the Maintenance of Long-Term Potentiation in the Hippocampal CA1 Region
Y1  - 2002/05/01 
JF  - The Journal of Neuroscience 
JO  - The Journal of Neuroscience 
SP  - 3359 
EP  - 3365 
DO  - 10.1523/JNEUROSCI.22-09-03359.2002 
VL  - 22 
IS  - 9 
UR  - http://www.jneurosci.org/content/22/9/3359.abstract 
N2  - Several signal transduction pathways have been implicated in the induction of long-term potentiation (LTP), yet the signal transduction mechanisms behind the maintenance–expression phase of LTP are still poorly understood. We investigated the role of phosphatidylinositol 3-kinase (PI3-kinase) in LTP at Schaffer collateral/commissural fiber–CA1 synapses in rat hippocampal slices using biochemical approaches and extracellular electrophysiological recordings. We observed that PI3-kinase activity was induced in the CA1 region during LTP of field EPSPs (fEPSPs) and that two structurally unrelated PI3-kinase inhibitors, LY294002 and wortmannin, abated established LTP, suggesting that PI3-kinase is involved in the maintenance–expression phase of LTP. However, LTP recovered after washout of the reversible PI3-kinase inhibitor LY294002, confirming that LTP maintenance and expression are distinct events and indicating that PI3-kinase activity is required for LTP expression rather than for its maintenance. Interestingly, preincubation with LY294002 did not prevent LTP induction. In fact, if LY294002 was withdrawn 5 min after high-frequency stimulation, an LTP of fEPSP was seen. Last, a voltage-dependent calcium channel-dependent form of LTP in the CA1 could also be reversibly abated by LY294002, raising the possibility that PI3-kinase could be required for the expression of multiple forms of synaptic potentiation. 
ER  -