@ARTICLE{10.3389/fnmol.2012.00022, AUTHOR={Rozov, Andrei and Sprengel, Rolf and Seeburg, Peter}, TITLE={GluA2-lacking AMPA receptors in hippocampal CA1 cell synapses: evidence from gene-targeted mice}, JOURNAL={Frontiers in Molecular Neuroscience}, VOLUME={5}, YEAR={2012}, URL={https://www.frontiersin.org/articles/10.3389/fnmol.2012.00022}, DOI={10.3389/fnmol.2012.00022}, ISSN={1662-5099}, ABSTRACT={The GluA2 subunit in heteromeric alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor channels restricts Ca2+ permeability and block by polyamines, rendering linear the current-voltage relationship of these glutamate-gated cation channels. Although GluA2-lacking synaptic AMPA receptors occur in GABA-ergic inhibitory neurons, hippocampal CA1 pyramidal cell synapses are widely held to feature only GluA2 containing AMPA receptors. A controversy has arisen from reports of GluA2-lacking AMPA receptors at hippocampal CA3-to-CA1 cell synapses and a study contesting these findings. Here we sought independent evidence for the presence of GluA2-lacking AMPA receptors in CA1 pyramidal cell synapses by probing the sensitivity of their gated cation channels in wild-type (WT) mice and gene-targeted mouse mutants to philanthotoxin, a specific blocker of GluA2-lacking AMPA receptors. The mutants either lacked GluA2 for maximal philanthotoxin sensitivity, or, for minimal sensitivity, expressed GluA1 solely in a Q/R site-edited version or not at all. Our comparative electrophysiological analyses provide incontrovertible evidence for the presence in wild-type CA1 pyramidal cell synapses of GluA2-less AMPA receptor channels. This article is part of a Special Issue entitled “Calcium permeable AMPARs in synaptic plasticity and disease.”} }