SUBUNIT COMPOSITION, KINETIC, AND PERMEATION PROPERTIES OF AMPA RECEPTORS IN SINGLE NEOCORTICAL NONPYRAMIDAL CELLS

Native AMPA receptors (AMPARs) were investigated in neocortical fast-s piking (FS) and regular-spiking nonpyramidal (RSNP) cells. The onset o f and recovery from desensitization as well as current rectification a nd single-channel conductance were studied by using fast glutamate app lication to outside-out patches. The GluR1-4 subunit, flip/flop splici ng, and R/G editing expression patterns of functionally characterized cells were determined by single-cell reverse transcription-PCR to corr elate the subunit composition of native AMPARs with their functional p roperties. Our sample, mostly constituted by RSNP neurons, predominant ly expressed GluR3 flip and GluR2 flop. In individual cells, flip/flop splicing of each subunit appeared to be regulated independently, wher eas for R/G editing all subunits were either almost fully edited or un edited. We confirmed that the relative GluR2 expression controls the p ermeation properties of native AMPARs, whereas none of the single mole cular