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NMDA receptor‐dependent long‐term potentiation in mouse hippocampal interneurons shows a unique dependence on Ca 2+ /calmodulin‐dependent kinases
Author(s) -
Lamsa Karri,
Irvine Elaine E.,
Giese K. Peter,
Kullmann Dimitri M.
Publication year - 2007
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2007.137380
Subject(s) - long term potentiation , nmda receptor , ltp induction , hippocampal formation , neuroscience , excitatory postsynaptic potential , chemistry , postsynaptic potential , neurotransmission , biology , inhibitory postsynaptic potential , microbiology and biotechnology , receptor , biochemistry
Long‐term potentiation (LTP) of excitatory synaptic transmission plays a major role in memory encoding in the cerebral cortex. It can be elicited at many synapses on principal cells, where it depends on Ca 2+ influx through postsynaptic N ‐methyl‐ d ‐aspartic acid (NMDA) receptors. Ca 2+ influx triggers phosphorylation of several kinases, in particular Ca 2+ /calmodulin‐dependent kinase type II (CaMKII). Auto‐phosphorylation of CaMKII is a key step in the LTP induction cascade, as revealed by the absence of LTP in hippocampal pyramidal neurons of αCaMKII T286A‐mutant mice, where auto‐phosphorylation of the α isoform at residue T286 is prevented. A subset of hippocampal interneurons mediating feed‐forward inhibition also exhibit NMDA receptor‐dependent LTP, which shows all the cardinal features of Hebbian LTP in pyramidal neurons. This is unexpected, because αCaMKII has not been detected in interneurons. Here we show that pathway‐specific NMDA receptor‐dependent LTP is intact in hippocampal inhibitory interneurons of αCaMKII T286A‐mutant mice, although in pyramidal cells it is blocked. However, LTP in interneurons is blocked by broad‐spectrum pharmacological inhibition of Ca 2+ /calmodulin‐dependent kinases. The results suggest that non‐α Ca 2+ /calmodulin‐dependent kinases substitute for the α isoform in NMDA receptor‐dependent LTP in interneurons.