PT  - JOURNAL ARTICLE
AU  - Lian Zhang
AU  - Timo Kirschstein
AU  - Britta Sommersberg
AU  - Malte Merkens
AU  - Denise Manahan-Vaughan
AU  - Ype Elgersma
AU  - Heinz Beck
TI  - Hippocampal Synaptic Metaplasticity Requires Inhibitory Autophosphorylation of Ca<sup>2+</sup>/Calmodulin-Dependent Kinase II
AID  - 10.1523/JNEUROSCI.2086-05.2005
DP  - 2005 Aug 17
TA  - The Journal of Neuroscience
PG  - 7697--7707
VI  - 25
IP  - 33
4099  - http://www.jneurosci.org/content/25/33/7697.short
4100  - http://www.jneurosci.org/content/25/33/7697.full
SO  - J. Neurosci.2005 Aug 17; 25
AB  - Virtually all CNS synapses display the potential for activity-dependent long-term potentiation (LTP) and/or long-term depression (LTD). Intriguingly, the potential to exhibit LTP or LTD at many central synapses itself is powerfully modulated by previous synaptic activity. This higher-order form of plasticity has been termed metaplasticity. Here, we show that inhibitory autophosphorylation of Ca2+/calmodulin-dependent kinase II (CaMKII) is required for hippocampal metaplasticity at the lateral perforant path-dentate granule cell synapse. Brief 10 Hz priming, which does not affect basal synaptic transmission, caused a dramatic, pathway-specific and long-lasting (up to 18 h) reduction in subsequently evoked LTP at lateral perforant path synapses. In contrast, LTD was unaffected by priming. The induction of lateral perforant path metaplasticity required the activation of NMDA receptors during priming. In addition, metaplasticity was absent in knock-in mice expressing αCaMKII that cannot undergo inhibitory phosphorylation, indicating that inhibitory autophosphorylation of αCaMKII at threonines 305/306 is required for metaplasticity. Metaplasticity was not observed in the medial perforant pathway, consistent with the observation that CaMKII activity was not required for the induction of LTP at this synapse. Thus, modulation of αCaMKII activity via autophosphorylation at Thr305/Thr306 is a key mechanism for metaplasticity that may be of importance in the integration of temporally separated episodes of activity.