Send to:

Choose Destination
See comment in PubMed Commons below
J Neurosci. 2011 Jun 15;31(24):8841-50. doi: 10.1523/JNEUROSCI.1358-11.2011.

Persistent long-term synaptic plasticity requires activation of a new signaling pathway by additional stimuli.

Author information

  • 1Department of Neuroscience, Columbia University College of Physicians and Surgeons, New York State Psychiatric Institute, New York, New York 10032, USA.


Most memories are strengthened by additional stimuli, but it is unclear how additional stimulation or training reinforces long-term memory. To address this we examined whether long-term facilitation (LTF) of Aplysia sensorimotor synapses in cell culture-a cellular correlate of long-term sensitization of defensive withdrawal reflexes in Aplysia californica-can be prolonged by additional stimulation. We found that 1 d treatment with serotonin (5-HT; five brief applications at 20 min intervals) produced LTF lasting ∼3 d, whereas 2 d of such 5-HT treatments induced a persistent LTF lasting >7 d. Incubation with the protein synthesis inhibitor rapamycin during the second set of 5-HT treatments abolished all facilitation, and synapse strength returned prematurely to baseline. Persistent LTF required more persistent elevation in the expression of the neurotrophin-like peptide sensorin and its secretion. Activation of protein kinase C (PKC) during the second day of 5-HT treatments, not required for LTF or changes in sensorin expression during the first set of 5-HT treatments, is critical for persistent LTF and replaces phosphoinositide 3 kinase (PI3K) activity in mediating the increase in sensorin expression. In contrast, activations of PKC during the first day of 5-HT treatments and PI3K during the second day of 5-HT treatments are unnecessary for persistent LTF or the increases in sensorin expression. Thus, additional stimuli make preexisting plasticity labile as they recruit a new signaling cascade to regulate the synthesis of a neurotrophin-like peptide required for persistent alterations in synaptic efficacy.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk