PT  - JOURNAL ARTICLE
AU  - Geoffrey T. Swanson
AU  - Sunjeev K. Kamboj
AU  - Stuart G. Cull-Candy
TI  - Single-Channel Properties of Recombinant AMPA Receptors Depend on RNA Editing, Splice Variation, and Subunit Composition
AID  - 10.1523/JNEUROSCI.17-01-00058.1997
DP  - 1997 Jan 01
TA  - The Journal of Neuroscience
PG  - 58--69
VI  - 17
IP  - 1
4099  - http://www.jneurosci.org/content/17/1/58.short
4100  - http://www.jneurosci.org/content/17/1/58.full
SO  - J. Neurosci.1997 Jan 01; 17
AB  - Non-NMDA glutamate receptor subunits of the AMPA-preferring subfamily combine to form ion channels with heterogeneous functional properties. We have investigated the effects of RNA editing at the Q/R site, splice variation of the “flip/flop” cassette, and multimeric subunit assembly on the single-channel conductance and kinetic properties of the recombinant AMPA receptors formed from GluR2 and GluR4 expressed in HEK 293 cells. We found that AMPA receptor single-channel conductance was dependent on the Q/R site editing state of the subunits comprising the channel. Calcium-permeable (unedited) channels had resolvable single-channel events with main conductance states of 7–8 pS, whereas fully edited GluR2 channels had very low conductances of ∼300 fS (estimated from noise analysis). Additionally, the flip splice variant of GluR4 conferred agonist-dependent conductance properties reminiscent of those found for a subset of AMPA receptors in cultured cerebellar granule cells. These results provide a description of the single-channel properties of certain recombinant AMPA receptors and suggest that the single-channel conductance may be determined by the expression of edited GluR2 subunits in neurons.